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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Flapless versus Conventional Flapped Dental Implant Surgery: A Meta-Analysis</title><author><name sortKey="Chrcanovic, Bruno Ramos" sort="Chrcanovic, Bruno Ramos" uniqKey="Chrcanovic B" first="Bruno Ramos" last="Chrcanovic">Bruno Ramos Chrcanovic</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation></author><author><name sortKey="Albrektsson, Tomas" sort="Albrektsson, Tomas" uniqKey="Albrektsson T" first="Tomas" last="Albrektsson">Tomas Albrektsson</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation><affiliation><nlm:aff id="aff2"><addr-line>Department of Biomaterials, Göteborg University, Göteborg, Sweden</addr-line></nlm:aff></affiliation></author><author><name sortKey="Wennerberg, Ann" sort="Wennerberg, Ann" uniqKey="Wennerberg A" first="Ann" last="Wennerberg">Ann Wennerberg</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">24950053</idno><idno type="pmc">4065043</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4065043</idno><idno type="RBID">PMC:4065043</idno><idno type="doi">10.1371/journal.pone.0100624</idno><date when="2014">2014</date><idno type="wicri:Area/Pmc/Corpus">000430</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">000430</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">Flapless versus Conventional Flapped Dental Implant Surgery: A Meta-Analysis</title><author><name sortKey="Chrcanovic, Bruno Ramos" sort="Chrcanovic, Bruno Ramos" uniqKey="Chrcanovic B" first="Bruno Ramos" last="Chrcanovic">Bruno Ramos Chrcanovic</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation></author><author><name sortKey="Albrektsson, Tomas" sort="Albrektsson, Tomas" uniqKey="Albrektsson T" first="Tomas" last="Albrektsson">Tomas Albrektsson</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation><affiliation><nlm:aff id="aff2"><addr-line>Department of Biomaterials, Göteborg University, Göteborg, Sweden</addr-line></nlm:aff></affiliation></author><author><name sortKey="Wennerberg, Ann" sort="Wennerberg, Ann" uniqKey="Wennerberg A" first="Ann" last="Wennerberg">Ann Wennerberg</name><affiliation><nlm:aff id="aff1"><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></nlm:aff></affiliation></author></analytic><series><title level="j">PLoS ONE</title><idno type="eISSN">1932-6203</idno><imprint><date when="2014">2014</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><p>The aim of this study was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants being inserted by a flapless surgical procedure versus the open flap technique, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 23 publications. The I<sup>2</sup> statistic was used to express the percentage of the total variation across studies due to heterogeneity. The inverse variance method was used for random-effects model or fixed-effects model, when indicated. The estimates of relative effect were expressed in risk ratio (RR) and mean difference (MD) in millimeters. Sixteen studies were judged to be at high risk of bias, whereas two studies were considered of moderate risk of bias, and five studies of low risk of bias. The funnel plots indicated absence of publication bias for the three outcomes analyzed. The test for overall effect showed that the difference between the procedures (flapless vs. open flap surgery) significantly affect the implant failure rates (<italic>P</italic> = 0.03), with a RR of 1.75 (95% CI 1.07–2.86). However, a sensitivity analysis revealed differences when studies of high and low risk of bias were pooled separately. Thus, the results must be interpreted carefully. No apparent significant effects of flapless technique on the occurrence of postoperative infection (P = 0.96; RR 0.96, 95% CI 0.23–4.03) or on the marginal bone loss (<italic>P</italic> = 0.16; MD −0.07 mm, 95% CI −0.16–0.03) were observed.</p></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Ozan, O" uniqKey="Ozan O">O Ozan</name></author><author><name sortKey="Turkyilmaz, I" uniqKey="Turkyilmaz I">I Turkyilmaz</name></author><author><name sortKey="Yilmaz, B" uniqKey="Yilmaz B">B Yilmaz</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Rocci, A" uniqKey="Rocci A">A Rocci</name></author><author><name sortKey="Martignoni, M" uniqKey="Martignoni M">M Martignoni</name></author><author><name sortKey="Gottlow, J" uniqKey="Gottlow J">J Gottlow</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Arisan, V" uniqKey="Arisan V">V Arisan</name></author><author><name sortKey="Karabuda, Cz" uniqKey="Karabuda C">CZ Karabuda</name></author><author><name sortKey="Ozdemir, T" uniqKey="Ozdemir T">T Ozdemir</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sunitha, Rv" uniqKey="Sunitha R">RV Sunitha</name></author><author><name sortKey="Sapthagiri, E" uniqKey="Sapthagiri E">E Sapthagiri</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="De Bruyn, H" uniqKey="De Bruyn H">H De Bruyn</name></author><author><name sortKey="Atashkadeh, M" uniqKey="Atashkadeh M">M Atashkadeh</name></author><author><name sortKey="Cosyn, J" uniqKey="Cosyn J">J Cosyn</name></author><author><name sortKey="Van De Velde, T" uniqKey="Van De Velde T">T van de Velde</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Albrektsson, T" uniqKey="Albrektsson T">T Albrektsson</name></author><author><name sortKey="Wennerberg, A" uniqKey="Wennerberg A">A Wennerberg</name></author></analytic></biblStruct><biblStruct></biblStruct><biblStruct></biblStruct><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Cannizzaro, G" uniqKey="Cannizzaro G">G Cannizzaro</name></author><author><name sortKey="Leone, M" uniqKey="Leone M">M Leone</name></author><author><name sortKey="Consolo, U" uniqKey="Consolo U">U Consolo</name></author><author><name sortKey="Ferri, V" uniqKey="Ferri V">V Ferri</name></author><author><name sortKey="Esposito, M" uniqKey="Esposito M">M Esposito</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Covani, U" uniqKey="Covani U">U Covani</name></author><author><name sortKey="Cornelini, R" uniqKey="Cornelini R">R Cornelini</name></author><author><name sortKey="Barone, A" uniqKey="Barone A">A Barone</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lindeboom, Ja" uniqKey="Lindeboom J">JA Lindeboom</name></author><author><name sortKey="Van Wijk, Aj" uniqKey="Van Wijk A">AJ van Wijk</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Van De Velde, T" uniqKey="Van De Velde T">T Van de Velde</name></author><author><name sortKey="Sennerby, L" uniqKey="Sennerby L">L Sennerby</name></author><author><name sortKey="De Bruyn, H" uniqKey="De Bruyn H">H De Bruyn</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Cannizzaro, G" uniqKey="Cannizzaro G">G Cannizzaro</name></author><author><name sortKey="Felice, P" uniqKey="Felice P">P Felice</name></author><author><name sortKey="Leone, M" uniqKey="Leone M">M Leone</name></author><author><name sortKey="Checchi, V" uniqKey="Checchi V">V Checchi</name></author><author><name sortKey="Esposito, M" uniqKey="Esposito M">M Esposito</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Froum, Sj" uniqKey="Froum S">SJ Froum</name></author><author><name sortKey="Cho, Sc" uniqKey="Cho S">SC Cho</name></author><author><name sortKey="Elian, N" uniqKey="Elian N">N Elian</name></author><author><name sortKey="Romanos, G" uniqKey="Romanos G">G Romanos</name></author><author><name sortKey="Jalbout, Z" uniqKey="Jalbout Z">Z Jalbout</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Al Juboori, Mj" uniqKey="Al Juboori M">MJ Al-Juboori</name></author><author><name sortKey="Bin Abdulrahaman, S" uniqKey="Bin Abdulrahaman S">S Bin Abdulrahaman</name></author><author><name sortKey="Jassan, A" uniqKey="Jassan A">A Jassan</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tsoukaki, M" uniqKey="Tsoukaki M">M Tsoukaki</name></author><author><name sortKey="Kalpidis, Cd" uniqKey="Kalpidis C">CD Kalpidis</name></author><author><name sortKey="Sakellari, D" uniqKey="Sakellari D">D Sakellari</name></author><author><name sortKey="Tsalikis, L" uniqKey="Tsalikis L">L Tsalikis</name></author><author><name sortKey="Mikrogiorgis, G" uniqKey="Mikrogiorgis G">G Mikrogiorgis</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Nkenke, E" uniqKey="Nkenke E">E Nkenke</name></author><author><name sortKey="Eitner, S" uniqKey="Eitner S">S Eitner</name></author><author><name sortKey="Radespiel Troger, M" uniqKey="Radespiel Troger M">M Radespiel-Tröger</name></author><author><name sortKey="Vairaktaris, E" uniqKey="Vairaktaris E">E Vairaktaris</name></author><author><name sortKey="Neukam, Fw" uniqKey="Neukam F">FW Neukam</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Villa, R" uniqKey="Villa R">R Villa</name></author><author><name sortKey="Rangert, B" uniqKey="Rangert B">B Rangert</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mal, P" uniqKey="Mal P">P Maló</name></author><author><name sortKey="Nobre, Md" uniqKey="Nobre M">MD Nobre</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Katsoulis, J" uniqKey="Katsoulis J">J Katsoulis</name></author><author><name sortKey="Avrampou, M" uniqKey="Avrampou M">M Avrampou</name></author><author><name sortKey="Spycher, C" uniqKey="Spycher C">C Spycher</name></author><author><name sortKey="Stipic, M" uniqKey="Stipic M">M Stipic</name></author><author><name sortKey="Enkling, N" uniqKey="Enkling N">N Enkling</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Marcelis, K" uniqKey="Marcelis K">K Marcelis</name></author><author><name sortKey="Vercruyssen, M" uniqKey="Vercruyssen M">M Vercruyssen</name></author><author><name sortKey="Naert, I" uniqKey="Naert I">I Naert</name></author><author><name sortKey="Teughels, W" uniqKey="Teughels W">W Teughels</name></author><author><name sortKey="Quirynen, M" uniqKey="Quirynen M">M Quirynen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Meizi, E" uniqKey="Meizi E">E Meizi</name></author><author><name sortKey="Meir, M" uniqKey="Meir M">M Meir</name></author><author><name sortKey="Laster, Z" uniqKey="Laster Z">Z Laster</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kinsel, Rp" uniqKey="Kinsel R">RP Kinsel</name></author><author><name sortKey="Liss, M" uniqKey="Liss M">M Liss</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sennerby, L" uniqKey="Sennerby L">L Sennerby</name></author><author><name sortKey="Rocci, A" uniqKey="Rocci A">A Rocci</name></author><author><name sortKey="Becker, W" uniqKey="Becker W">W Becker</name></author><author><name sortKey="Jonsson, L" uniqKey="Jonsson L">L Jonsson</name></author><author><name sortKey="Johansson, La" uniqKey="Johansson L">LA Johansson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Danza, M" uniqKey="Danza M">M Danza</name></author><author><name sortKey="Zollin, I" uniqKey="Zollin I">I Zollin</name></author><author><name sortKey="Carinci, F" uniqKey="Carinci F">F Carinci</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Berdougo, M" uniqKey="Berdougo M">M Berdougo</name></author><author><name sortKey="Fortin, T" uniqKey="Fortin T">T Fortin</name></author><author><name sortKey="Blanchet, E" uniqKey="Blanchet E">E Blanchet</name></author><author><name sortKey="Isidori, M" uniqKey="Isidori M">M Isidori</name></author><author><name sortKey="Bosson, Jl" uniqKey="Bosson J">JL Bosson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Rousseau, P" uniqKey="Rousseau P">P Rousseau</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shrier, I" uniqKey="Shrier I">I Shrier</name></author><author><name sortKey="Boivin, Jf" uniqKey="Boivin J">JF Boivin</name></author><author><name sortKey="Steele, Rj" uniqKey="Steele R">RJ Steele</name></author><author><name sortKey="Platt, Rw" uniqKey="Platt R">RW Platt</name></author><author><name sortKey="Furlan, A" uniqKey="Furlan A">A Furlan</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sharaf, B" uniqKey="Sharaf B">B Sharaf</name></author><author><name sortKey="Jandali Rifai, M" uniqKey="Jandali Rifai M">M Jandali-Rifai</name></author><author><name sortKey="Susarla, Sm" uniqKey="Susarla S">SM Susarla</name></author><author><name sortKey="Dodson, Tb" uniqKey="Dodson T">TB Dodson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ten Bruggenkate, Cm" uniqKey="Ten Bruggenkate C">CM ten Bruggenkate</name></author><author><name sortKey="Van Der Kwast, Wa" uniqKey="Van Der Kwast W">WA van der Kwast</name></author><author><name sortKey="Oosterbeek, Hs" uniqKey="Oosterbeek H">HS Oosterbeek</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Pedrosa, Ar" uniqKey="Pedrosa A">AR Pedrosa</name></author><author><name sortKey="Martins, Md" uniqKey="Martins M">MD Martins</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Leao, Nlc" uniqKey="Leao N">NLC Leão</name></author><author><name sortKey="Martins, Md" uniqKey="Martins M">MD Martins</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Martins, Md" uniqKey="Martins M">MD Martins</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wennerberg, A" uniqKey="Wennerberg A">A Wennerberg</name></author><author><name sortKey="Albrektsson, T" uniqKey="Albrektsson T">T Albrektsson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Oliveira, Dr" uniqKey="Oliveira D">DR Oliveira</name></author><author><name sortKey="Cust Dio, Al" uniqKey="Cust Dio A">AL Custódio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Van De Velde, T" uniqKey="Van De Velde T">T Van de Velde</name></author><author><name sortKey="Glor, F" uniqKey="Glor F">F Glor</name></author><author><name sortKey="De Bruyn, H" uniqKey="De Bruyn H">H De Bruyn</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Campelo, Ld" uniqKey="Campelo L">LD Campelo</name></author><author><name sortKey="Camara, Jr" uniqKey="Camara J">JR Camara</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chiapasco, M" uniqKey="Chiapasco M">M Chiapasco</name></author><author><name sortKey="Zaniboni, M" uniqKey="Zaniboni M">M Zaniboni</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Annibali, S" uniqKey="Annibali S">S Annibali</name></author><author><name sortKey="Ripari, M" uniqKey="Ripari M">M Ripari</name></author><author><name sortKey="La Monaca, G" uniqKey="La Monaca G">G La Monaca</name></author><author><name sortKey="Tonoli, F" uniqKey="Tonoli F">F Tonoli</name></author><author><name sortKey="Cristalli, Mp" uniqKey="Cristalli M">MP Cristalli</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wood, Dl" uniqKey="Wood D">DL Wood</name></author><author><name sortKey="Hoag, Pm" uniqKey="Hoag P">PM Hoag</name></author><author><name sortKey="Donnenfeld, Ow" uniqKey="Donnenfeld O">OW Donnenfeld</name></author><author><name sortKey="Rosenfeld, Ld" uniqKey="Rosenfeld L">LD Rosenfeld</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Abreu, Mh" uniqKey="Abreu M">MH Abreu</name></author><author><name sortKey="Freire Maia, B" uniqKey="Freire Maia B">B Freire-Maia</name></author><author><name sortKey="Souza, Ln" uniqKey="Souza L">LN Souza</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chrcanovic, Br" uniqKey="Chrcanovic B">BR Chrcanovic</name></author><author><name sortKey="Abreu, Mh" uniqKey="Abreu M">MH Abreu</name></author><author><name sortKey="Freire Maia, B" uniqKey="Freire Maia B">B Freire-Maia</name></author><author><name sortKey="Souza, Ln" uniqKey="Souza L">LN Souza</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">PLoS One</journal-id><journal-id journal-id-type="iso-abbrev">PLoS ONE</journal-id><journal-id journal-id-type="publisher-id">plos</journal-id><journal-id journal-id-type="pmc">plosone</journal-id><journal-title-group><journal-title>PLoS ONE</journal-title></journal-title-group><issn pub-type="epub">1932-6203</issn><publisher><publisher-name>Public Library of Science</publisher-name><publisher-loc>San Francisco, USA</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">24950053</article-id><article-id pub-id-type="pmc">4065043</article-id><article-id pub-id-type="publisher-id">PONE-D-14-12786</article-id><article-id pub-id-type="doi">10.1371/journal.pone.0100624</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Medicine and Health Sciences</subject><subj-group><subject>Oral Medicine</subject><subj-group><subject>Oral Diseases</subject><subj-group><subject>Periodontal Diseases</subject></subj-group></subj-group><subj-group><subject>Dentistry</subject><subject>Oral Health</subject></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physical Sciences</subject><subj-group><subject>Mathematics</subject><subj-group><subject>Statistics (Mathematics)</subject><subj-group><subject>Statistical Methods</subject><subj-group><subject>Meta-Analysis</subject></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Research and Analysis Methods</subject><subj-group><subject>Mathematical and Statistical Techniques</subject></subj-group><subj-group><subject>Research Assessment</subject><subj-group><subject>Systematic Reviews</subject></subj-group></subj-group></subj-group></article-categories><title-group><article-title>Flapless versus Conventional Flapped Dental Implant Surgery: A Meta-Analysis</article-title><alt-title alt-title-type="running-head">Flapless vs. Flapped Dental Implant Surgery: A Meta-Analysis</alt-title></title-group><contrib-group><contrib contrib-type="author"><name><surname>Chrcanovic</surname><given-names>Bruno Ramos</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib><contrib contrib-type="author"><name><surname>Albrektsson</surname><given-names>Tomas</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib><contrib contrib-type="author"><name><surname>Wennerberg</surname><given-names>Ann</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib></contrib-group><aff id="aff1"><label>1</label><addr-line>Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden,</addr-line></aff><aff id="aff2"><label>2</label><addr-line>Department of Biomaterials, Göteborg University, Göteborg, Sweden</addr-line></aff><contrib-group><contrib contrib-type="editor"><name><surname>Glogauer</surname><given-names>Michael</given-names></name><role>Editor</role><xref ref-type="aff" rid="edit1"></xref></contrib></contrib-group><aff id="edit1"><addr-line>University of Toronto, Canada</addr-line></aff><author-notes><corresp id="cor1">* E-mail: <email>bruno.chrcanovic@mah.se</email></corresp><fn fn-type="conflict"><p><bold>Competing Interests: </bold>The authors have declared that no competing interests exist.</p></fn><fn fn-type="con"><p>Contributed to the writing of the manuscript: BRC. Conception and design of the work and acquisition of data: BRC TA AW. Meta-analysis: BRC. Interpretation of data: BRC TA AW. Revised the article critically for important intellectual content: BRC TA AW. Final approval of the version to be published: BRC TA AW.</p></fn></author-notes><pub-date pub-type="collection"><year>2014</year></pub-date><pub-date pub-type="epub"><day>20</day><month>6</month><year>2014</year></pub-date><volume>9</volume><issue>6</issue><elocation-id>e100624</elocation-id><history><date date-type="received"><day>21</day><month>3</month><year>2014</year></date><date date-type="accepted"><day>29</day><month>5</month><year>2014</year></date></history><permissions><copyright-year>2014</copyright-year><copyright-holder>Chrcanovic et al</copyright-holder><license><license-p>This is an open-access article distributed under the terms of the <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution License</ext-link>, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p></license></permissions><abstract><p>The aim of this study was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants being inserted by a flapless surgical procedure versus the open flap technique, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 23 publications. The I<sup>2</sup> statistic was used to express the percentage of the total variation across studies due to heterogeneity. The inverse variance method was used for random-effects model or fixed-effects model, when indicated. The estimates of relative effect were expressed in risk ratio (RR) and mean difference (MD) in millimeters. Sixteen studies were judged to be at high risk of bias, whereas two studies were considered of moderate risk of bias, and five studies of low risk of bias. The funnel plots indicated absence of publication bias for the three outcomes analyzed. The test for overall effect showed that the difference between the procedures (flapless vs. open flap surgery) significantly affect the implant failure rates (<italic>P</italic> = 0.03), with a RR of 1.75 (95% CI 1.07–2.86). However, a sensitivity analysis revealed differences when studies of high and low risk of bias were pooled separately. Thus, the results must be interpreted carefully. No apparent significant effects of flapless technique on the occurrence of postoperative infection (P = 0.96; RR 0.96, 95% CI 0.23–4.03) or on the marginal bone loss (<italic>P</italic> = 0.16; MD −0.07 mm, 95% CI −0.16–0.03) were observed.</p></abstract><funding-group><funding-statement>This work was supported by CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brazil. The supportive institution had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.</funding-statement></funding-group><counts><page-count count="14"></page-count></counts><custom-meta-group><custom-meta id="data-availability"><meta-name>Data Availability</meta-name><meta-value>The authors confirm that all data underlying the findings are fully available without restriction. Not applicable.</meta-value></custom-meta></custom-meta-group></article-meta><notes><title>Data Availability</title><p>The authors confirm that all data underlying the findings are fully available without restriction. Not applicable.</p></notes></front><body><sec id="s1"><title>Introduction</title><p>When placing dental implants, a flap is traditionally elevated to better visualize the implant recipient site, providing that some anatomical landmarks are clearly identified and protected. When a limited amount of bone is available, a flap elevation can help implant placement to reduce the risk of bone fenestrations or perforations <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>. More recently, the concept of flapless implant surgery has been introduced for the patients with sufficient keratinized gingival tissue and bone volume in the implant recipient site. In a flapless procedure, a dental implant is installed through the mucosal tissues without reflecting a flap. The alleged reasons to choose the flapless technique are to minimize the possibility of postoperative peri-implant tissue loss and to overcome the challenge of soft tissue management during or after surgery <xref rid="pone.0100624-Rocci1" ref-type="bibr">[2]</xref>. Other alleged advantages of the flapless implant surgery include less traumatic surgery, decreased operative time, rapid postsurgical healing, fewer postoperative complications and increased patient comfort <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>. A disadvantage of this technique is that the true topography of the underlying available bone cannot be observed because the mucogingival tissues are not raised, which may increase the risk for unwanted perforations which in its turn could lead to esthetical problems or implant losses <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>. Moreover, there is the potential for thermal damage secondary to reduced access for external irrigation during osteotomy preparation <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>.</p><p>Researchers have been trying to evaluate whether the insertion of implants by the flapless technique may influence the survival of dental implants. However, some studies may lack statistical power, given the small number of patients per group in the clinical trials comparing the techniques. Thus, we conducted a meta-analysis of previously published clinical studies to investigate whether there are any positive effects of flapless implant insertion surgery on implant failure rates, postoperative infection, and marginal bone loss in comparison with the more traditional open flap technique. The present study presents a more detailed and profound analysis of the influence of these two techniques on the implant failure rates, previously assessed in a published systematic review <xref rid="pone.0100624-Chrcanovic1" ref-type="bibr">[6]</xref>.</p></sec><sec sec-type="materials|methods" id="s2"><title>Materials and Methods</title><p>This study followed the PRISMA Statement guidelines <xref rid="pone.0100624-Moher1" ref-type="bibr">[7]</xref>. A review protocol does not exist.</p><sec id="s2a"><title>Objective</title><p>The purpose of the present review was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants being inserted by a flapless surgical procedure versus the open flap technique, against the alternative hypothesis of a difference.</p></sec><sec id="s2b"><title>Search strategies</title><p>An electronic search without time or language restrictions was undertaken in March 2014 in the following databases: PubMed, Web of Science, and the Cochrane Oral Health Group Trials Register. The following terms were used in the search strategy on PubMed:</p><p>{Subject AND Adjective}</p><p>{<italic>Subject</italic>: (dental implant OR dental implant failure OR dental implant survival OR dental implant success [text words])</p><p>AND</p><p><italic>Adjective</italic>: (flapless OR flapped OR open flap [text words])}</p><p>Refining the results with the option “Dentistry Oral Surgery Medicine” selected within the filter “Research Areas”, the following terms were used in the search strategy on Web of Science:</p><p>{Subject AND Adjective}</p><p>{<italic>Subject</italic>: (dental implant failure OR dental implant survival OR dental implant success [title])</p><p>AND</p><p><italic>Adjective</italic>: (flapless surgery OR flapped surgery OR open flap surgery [title])}</p><p>The following terms were used in the search strategy on the Cochrane Oral Health Group Trials Register:</p><p>(dental implant OR dental implant failure OR dental implant survival OR dental implant success AND (flapless surgery OR flapped surgery OR open flap surgery))</p><p>A manual search of dental implants-related journals, including <italic>British Journal of Oral and Maxillofacial Surgery, Clinical Implant Dentistry and Related Research, Clinical Oral Implants Research, European Journal of Oral Implantology, Implant Dentistry, International Journal of Oral and Maxillofacial Implants, International Journal of Oral and Maxillofacial Surgery, International Journal of Periodontics and Restorative Dentistry, International Journal of Prosthodontics, Journal of Clinical Periodontology, Journal of Dental Research, Journal of Oral Implantology, Journal of Craniofacial Surgery, Journal of Cranio-Maxillofacial Surgery, and Journal of Maxillofacial and Oral Surgery, Journal of Oral and Maxillofacial Surgery, Journal of Periodontology,</italic> and <italic>Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology</italic>, was also performed.</p><p>The reference list of the identified studies and the relevant reviews on the subject were also scanned for possible additional studies. Moreover, online databases providing information about clinical trials in progress were checked (clinicaltrials.gov; <ext-link ext-link-type="uri" xlink:href="http://www.centerwatch.com/clinicaltrials">www.centerwatch.com/clinicaltrials</ext-link>; <ext-link ext-link-type="uri" xlink:href="http://www.clinicalconnection.com">www.clinicalconnection.com</ext-link>).</p></sec><sec id="s2c"><title>Inclusion and Exclusion Criteria</title><p>Eligibility criteria included clinical human studies, either randomized or not, comparing implant failure rates in any group of patients receiving titanium dental implants by a flapless surgical procedure versus the open flap technique. For this review, implant failure represents the complete loss of the implant. Exclusion criteria were case reports, technical reports, animal studies, <italic>In Vitro</italic> studies, and reviews papers.</p></sec><sec id="s2d"><title>Study selection</title><p>The titles and abstracts of all reports identified through the electronic searches were read independently by the three authors. For studies appearing to meet the inclusion criteria, or for which there were insufficient data in the title and abstract to make a clear decision, the full report was obtained. Disagreements were resolved by discussion between the authors.</p></sec><sec id="s2e"><title>Quality assessment</title><p>The quality assessment was performed by using the recommended approach for assessing risk of bias in studies included in Cochrane reviews <xref rid="pone.0100624-Higgins1" ref-type="bibr">[8]</xref>. The classification of the risk of bias potential for each study was based on the four following criteria: sequence generation (random selection in the population), allocation concealment (steps must be taken to secure strict implementation of the schedule of random assignments by preventing foreknowledge of the forthcoming allocations), incomplete outcome data (clear explanation of withdrawals and exclusions), and blinding (measures to blind study participants and personnel from knowledge of which intervention a participant received). The incomplete outcome data will also be considered addressed when there are no withdrawals and/or exclusions. A study that met all the criteria mentioned above was classified as having a low risk of bias, a study that did not meet one of these criteria was classified as having a moderate risk of bias. When two or more criteria were not met, the study was considered to have a high risk of bias.</p></sec><sec id="s2f"><title>Data extraction and meta-analysis</title><p>From the studies included in the final analysis, the following data was extracted (when available): year of publication, study design (randomized controlled trial – RCT, controlled clinical trial – CCT, retrospective study), unicenter or multicenter study, number of patients, patients' age, follow-up, days of antibiotic prophylaxis, mouth rinse with chlorhexidine, implant healing period, failed and placed implants, postoperative infection, marginal bone loss, implant surface modification, use of grafting procedures, use of a surgical guide, and presence of smokers among the patients. Contact with authors for possible missing data was performed.</p><p>Implant failure and postoperative infection were the dichotomous outcomes measures evaluated. Weighted mean differences were used to construct forest plots of marginal bone loss, a continuous outcome. The statistical unit for ‘implant failure’ and ‘marginal bone loss’ was the implant, and for ‘postoperative infection’ was the patient. Whenever outcomes of interest were not clearly stated, the data were not used for analysis. The I<sup>2</sup> statistic was used to express the percentage of the total variation across studies due to heterogeneity, with 25% corresponding to low heterogeneity, 50% to moderate and 75% to high. The inverse variance method was used for random-effects or fixed-effects model. Where statistically significant (<italic>P</italic><.10) heterogeneity is detected, a random-effects model was used to assess the significance of treatment effects. Where no statistically significant heterogeneity is found, analysis was performed using a fixed-effects model <xref rid="pone.0100624-Egger1" ref-type="bibr">[9]</xref>. In the inverse variance method the weight given to each study is chosen to be the inverse of the variance of the effect estimate (i.e. one over the square of its standard error) <xref rid="pone.0100624-Higgins1" ref-type="bibr">[8]</xref>. Thus larger studies, which have smaller standard errors, are given more weight than smaller studies, which have larger standard errors. This choice of weight minimizes the imprecision (uncertainty) of the pooled effect estimate. The basic data required for the analysis are an estimate of the intervention effect and its standard error from each study <xref rid="pone.0100624-Higgins1" ref-type="bibr">[8]</xref>.</p><p>The estimates of relative effect for dichotomous outcomes were expressed in risk ratio (RR) and in mean difference (MD) in millimeters for continuous outcomes, both with a 95% confidence interval (CI). Only if there were studies with similar comparisons reporting the same outcome measures was meta-analysis to be attempted. In the case where no events (or all events) are observed in both groups the study provides no information about relative probability of the event and is automatically omitted from the meta-analysis. In this (these) case(s), the term ‘not estimable’ is shown under the RR column of the forest plot table. The software used here automatically checks for problematic zero counts, and adds a fixed value of 0.5 to all cells of study results tables where the problems occur.</p><p>A funnel plot (plot of effect size versus standard error) will be drawn. Asymmetry of the funnel plot may indicate publication bias and other biases related to sample size, although the asymmetry may also represent a true relationship between trial size and effect size.</p><p>The data were analyzed using the statistical software Review Manager (version 5.2.8, The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark, 2014).</p></sec></sec><sec id="s3"><title>Results</title><sec id="s3a"><title>Literature search</title><p>The study selection process is summarized in <xref ref-type="fig" rid="pone-0100624-g001">Figure 1</xref>. The search strategy resulted in 1246 papers. The three reviewers independently screened the abstracts for those articles related to the focus question. The initial screening of titles and abstracts resulted in 82 full-text papers; 37 were cited in more than one research of terms. The full-text reports of the remaining 43 articles led to the exclusion of 23 because they did not meet the inclusion criteria; 15 studies were conducted in animals, 2 studies used zirconia implants, 4 studies compared the techniques but did not evaluate implant failures, and 2 articles were the same study published in different journals. Additional hand-searching of the reference lists of selected studies yielded two additional papers. Thus, a total of 23 publications were included in the review.</p><fig id="pone-0100624-g001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g001</object-id><label>Figure 1</label><caption><title>Study screening process – flow diagram.</title></caption><graphic xlink:href="pone.0100624.g001"></graphic></fig></sec><sec id="s3b"><title>Description of the Studies</title><p>Detailed data of the 23 included studies are listed in <xref ref-type="table" rid="pone-0100624-t001">Table 1</xref>. Ten RCTs <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>, <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>–<xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref>, seven CCTs <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref>–<xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref> and six retrospective studies <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref>–<xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> were included in the meta-analysis. Only three studies <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref>, <xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref> were multicenter. In five studies <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>, <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>–<xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref> both patients and operators/outcome assessors were blinded to the tested intervention. Six studies <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>, <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref>, <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref> had a follow-up up to 6 months, and six studies <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref>–<xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>, <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref> with a follow-up up to 1 year.</p><table-wrap id="pone-0100624-t001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.t001</object-id><label>Table 1</label><caption><title>Detailed data of the included studies.</title></caption><alternatives><graphic id="pone-0100624-t001-1" xlink:href="pone.0100624.t001"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col></colgroup><thead><tr><td align="left" rowspan="1" colspan="1">Authors</td><td align="left" rowspan="1" colspan="1">Published</td><td align="left" rowspan="1" colspan="1">Patients (n) (number per group)</td><td align="left" rowspan="1" colspan="1">Patients' Age Range (Average) (years)</td><td align="left" rowspan="1" colspan="1">Follow-up visits (or range)</td><td align="left" rowspan="1" colspan="1">Failed/Placed Implants (n)</td><td align="left" rowspan="1" colspan="1">Implant failure rate (%)</td><td align="left" rowspan="1" colspan="1"><italic>P</italic> value (for failure rate)</td><td align="left" rowspan="1" colspan="1">Antibiotics/mouth rinse (days)</td><td align="left" rowspan="1" colspan="1">Healing period/loading</td><td align="left" rowspan="1" colspan="1">Implant surface modification (brand)</td><td align="left" rowspan="1" colspan="1">Grafting</td><td align="left" rowspan="1" colspan="1">Observations</td></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1">Kinsel and Liss <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">43 (NM)</td><td align="left" rowspan="1" colspan="1">35–80 (58)</td><td align="left" rowspan="1" colspan="1">2–10 years</td><td align="left" rowspan="1" colspan="1">13/196 (G1) 3/148 (G2)</td><td align="left" rowspan="1" colspan="1">6.6 (G1) 2.0 (G2)</td><td align="left" rowspan="1" colspan="1">0.07</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">Immediate</td><td align="left" rowspan="1" colspan="1">TPS (SLA, Straumann, Basel, Switzerland; n = 131), sandblasted and acid-etched (SLA, Straumann, Basel, Switzerland; n = 213)</td><td align="left" rowspan="1" colspan="1">Grafting in 2 patients, with implants placed 5–6 months later</td><td align="left" rowspan="1" colspan="1">12 smokers, surgical guide (G1 and G2)</td></tr><tr><td align="left" rowspan="1" colspan="1">Nkenke et al. <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">10 (5, G1, 5, G2)</td><td align="left" rowspan="1" colspan="1">NM (65±10)</td><td align="left" rowspan="1" colspan="1">1 and 7 days, 12 months</td><td align="left" rowspan="1" colspan="1">0/30 (G1) 0/30 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">6 months</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Only in maxilla, use of CT-guided surgical stents (G1)</td></tr><tr><td align="left" rowspan="1" colspan="1">Ozan et al. <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">12 (5, G1; 7, G2)</td><td align="left" rowspan="1" colspan="1">NM (46±9)</td><td align="left" rowspan="1" colspan="1">6–14 months (mean 9±3)</td><td align="left" rowspan="1" colspan="1">0/14 (G1) 1/45 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 2.2 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">3 months (maxilla) 2 months (mandible)</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SwissPlus, Zimmer Dental, Carlsbad, USA)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of CT-guided surgical stents (G1), healing abutments screwed immediately</td></tr><tr><td align="left" rowspan="1" colspan="1">Villa and Rangert <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">33 (15, G1; 18, G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">10 days, 1, 3, 6 and 12 months</td><td align="left" rowspan="1" colspan="1">1/29 (G1) 1/47 (G2)</td><td align="left" rowspan="1" colspan="1">3.4 (G1) 2.1 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">6/14–21</td><td align="left" rowspan="1" colspan="1">Immediate and early loading</td><td align="left" rowspan="1" colspan="1">Oxidized (Brånemark Mk III and Mk IV and NobelSpeedy, TiUnite, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Implants placed in infected extraction sockets, no use of a surgical guide</td></tr><tr><td align="left" rowspan="1" colspan="1">Cannizzaro et al. <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">40 (20, G1; 20, G2)</td><td align="left" rowspan="1" colspan="1">18–62 (40.1, G1) 19–64 (37.4, G2)</td><td align="left" rowspan="1" colspan="1">3 years</td><td align="left" rowspan="1" colspan="1">0/52 (G1) 0/56 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">3/13</td><td align="left" rowspan="1" colspan="1">Immediate loading (G1), 4 months (maxilla) and 3 months (mandible) (G2)</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SwissPlus, Zimmer Dental, Carlsbad, USA)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of surgical templates based on diagnostic tooth arrangement (G1), 17 smokers (8, G1; 9, G2)</td></tr><tr><td align="left" rowspan="1" colspan="1">Covani et al. <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">20 (10, G1; 10, G2)</td><td align="left" rowspan="1" colspan="1">30–67 (NM)</td><td align="left" rowspan="1" colspan="1">6 months</td><td align="left" rowspan="1" colspan="1">1/10 (G1) 0/10 (G2)</td><td align="left" rowspan="1" colspan="1">10 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">4/21</td><td align="left" rowspan="1" colspan="1">6 months</td><td align="left" rowspan="1" colspan="1">Titanium plasma-sprayed coated (Premium, Sweden & Martina, Padova, Italy)</td><td align="left" rowspan="1" colspan="1">All implants: grafting with a mixture of collagen gel/corticocancellous porcine bone</td><td align="left" rowspan="1" colspan="1">Submerged implants, no use of a surgical guide, heavy smokers (>10 cigarettes/day) were excluded</td></tr><tr><td align="left" rowspan="1" colspan="1">Maló and Nobre <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">41 (20, G1; 21, G2)</td><td align="left" rowspan="1" colspan="1">19–79 (45.5)</td><td align="left" rowspan="1" colspan="1">6 months 1 year</td><td align="left" rowspan="1" colspan="1">1/32 (G1) 0/40 (G2)</td><td align="left" rowspan="1" colspan="1">3.1 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">6/60 (rinse with hyaluronic acid)</td><td align="left" rowspan="1" colspan="1">Immediate loading</td><td align="left" rowspan="1" colspan="1">Oxidized (NobelSpeedy, TiUnite, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide</td></tr><tr><td align="left" rowspan="1" colspan="1">Sennerby et al. <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">43 (NM)</td><td align="left" rowspan="1" colspan="1">NM (50)</td><td align="left" rowspan="1" colspan="1">1–18 months (mean 10.2)</td><td align="left" rowspan="1" colspan="1">6/76 (G1) 0/41 (G2)</td><td align="left" rowspan="1" colspan="1">7.9 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">Immediate/early (n = 95), from 6 weeks to 6 months (n = 22)</td><td align="left" rowspan="1" colspan="1">Anodically oxidized (NobelDirect, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">Minor bone grafting in 8 implants</td><td align="left" rowspan="1" colspan="1">Use of a slide-over guide sleeve to evaluate and determine the position of the implant (G1) Healed sites (n = 99) Extraction sockets (n = 18)</td></tr><tr><td align="left" rowspan="1" colspan="1">Danza et al. <xref rid="pone.0100624-Danza1" ref-type="bibr">[26]</xref></td><td align="left" rowspan="1" colspan="1">2009</td><td align="left" rowspan="1" colspan="1">93 (8, G1; 85, G2)</td><td align="left" rowspan="1" colspan="1">16–89 (48)</td><td align="left" rowspan="1" colspan="1">Mean of 14 months</td><td align="left" rowspan="1" colspan="1">0/66 (G1) 9/225 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 4.0 (G2)</td><td align="left" rowspan="1" colspan="1">0.3311</td><td align="left" rowspan="1" colspan="1">5/NP</td><td align="left" rowspan="1" colspan="1">Immediate or after 3 months</td><td align="left" rowspan="1" colspan="1">? (3D Alpha-Biomedical s.r.l., Pescara, Italy)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of CT-guided surgical template (G1), heavy smokers (>20 cigarettes/day) were excluded</td></tr><tr><td align="left" rowspan="1" colspan="1">Arisan et al. <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">52 (15, G1; 37, G2)</td><td align="left" rowspan="1" colspan="1">28–63 (48.4)</td><td align="left" rowspan="1" colspan="1">4 months</td><td align="left" rowspan="1" colspan="1">3/99 (G1) 5/242 (G2)</td><td align="left" rowspan="1" colspan="1">3.0 (G1) 2.1 (G2)</td><td align="left" rowspan="1" colspan="1">0.946</td><td align="left" rowspan="1" colspan="1">5/before surgery</td><td align="left" rowspan="1" colspan="1">2–4 months</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SPI-Element, Thommen Medical, Waldenburg, Switzerland, n = 180), sandblasted and acid-etched (XiVe, Dentsply-Friadent, Mannheim, Germany, n = 161)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of a stereolithographic surgical guide (G1) In G2: the surgical guide was used in 16 patients (101 implants), whereas in 21 patients it was not used (141 implants), heavy smokers (>10 cigarettes/day) were excluded</td></tr><tr><td align="left" rowspan="1" colspan="1">Berdougo et al. <xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">169 (99, G1; 76 G2)<xref ref-type="table-fn" rid="nt102">a</xref></td><td align="left" rowspan="1" colspan="1">20–84 (53.1±14.5)</td><td align="left" rowspan="1" colspan="1">1–4 years</td><td align="left" rowspan="1" colspan="1">10/271 (G1) 4/281 (G2)</td><td align="left" rowspan="1" colspan="1">3.7 (G1) 1.4 (G2)</td><td align="left" rowspan="1" colspan="1">0.1</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of an image-guided template (G1), 22 patients were smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Lindeboom and van Wijk <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">16 (8, G1; 8, G2)</td><td align="left" rowspan="1" colspan="1">NM (54.6±2.9, G1) NM (58.7±7.2, G2)</td><td align="left" rowspan="1" colspan="1">1 week 1 month 6 months <xref ref-type="table-fn" rid="nt103">b</xref></td><td align="left" rowspan="1" colspan="1">3/48 (G1) 0/48 (G2)<xref ref-type="table-fn" rid="nt103">b</xref></td><td align="left" rowspan="1" colspan="1">4.2 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">5/7</td><td align="left" rowspan="1" colspan="1">The implants were not loaded</td><td align="left" rowspan="1" colspan="1">Oxidized (NobelReplace, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of CT-guided surgical template (G1 and G2) No smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Rousseau <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">219 (121, G1; 98, G2)</td><td align="left" rowspan="1" colspan="1">23–84 (54.3±12.6)</td><td align="left" rowspan="1" colspan="1">4 weeks, 2–3 months, 2 years</td><td align="left" rowspan="1" colspan="1">3/174 (G1) 3/203 (G2)</td><td align="left" rowspan="1" colspan="1">1.7 (G1) 1.5 (G2)</td><td align="left" rowspan="1" colspan="1">0.46</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">2–3 months</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SLA, Straumann, Basel, Switzerland)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide</td></tr><tr><td align="left" rowspan="1" colspan="1">Van de Velde et al. <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">14 (split-mouth design)</td><td align="left" rowspan="1" colspan="1">39–75 (55.7)</td><td align="left" rowspan="1" colspan="1">1 week, 6 weeks, 3, 6, 12 and 18 months</td><td align="left" rowspan="1" colspan="1">1/36 (G1) 0/34 (G2)</td><td align="left" rowspan="1" colspan="1">2.8 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NP/before surgery</td><td align="left" rowspan="1" colspan="1">Immediate loading (G1), 6 weeks (G2)</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SLA, Straumann, Basel, Switzerland)</td><td align="left" rowspan="1" colspan="1">Bone grafts/sinus lifts: performed with a minimum of 6 months before implant installation</td><td align="left" rowspan="1" colspan="1">Use of a stereolithographic surgical guide (G1), heavy smokers (>10 cigarettes/day) were excluded</td></tr><tr><td align="left" rowspan="1" colspan="1">Cannizzaro et al. <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">40 (split-mouth design)</td><td align="left" rowspan="1" colspan="1">22–65 (44.5)</td><td align="left" rowspan="1" colspan="1">3 days, 10 days, 6 weeks, 8 weeks Every 3 months for 1 year</td><td align="left" rowspan="1" colspan="1">2/76 (G1) 2/67 (G2)</td><td align="left" rowspan="1" colspan="1">2.6 (G1) 3.0 (G2)</td><td align="left" rowspan="1" colspan="1">1.0</td><td align="left" rowspan="1" colspan="1">Preoperative/12</td><td align="left" rowspan="1" colspan="1">Immediate loading</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SwissPlus, Zimmer Dental, Carlsbad, USA)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Nonsubmerged implants, 49 extraction sockets implants (25, G1; 24, G2), no use of a surgical guide, 20 patients were smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">De Bruyn et al. <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">49 (NM)</td><td align="left" rowspan="1" colspan="1">20–79 (53)</td><td align="left" rowspan="1" colspan="1">1 and 3 years</td><td align="left" rowspan="1" colspan="1">0/28 (G1) 0/25 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">7/unknown number of days</td><td align="left" rowspan="1" colspan="1">3–6 months</td><td align="left" rowspan="1" colspan="1">Porous anodized surface (TiUnite, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide, 10 patients were smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Froum et al. <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">52 (60)<xref ref-type="table-fn" rid="nt104">c</xref> (27, G1; 25, G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">6 months, 1 year</td><td align="left" rowspan="1" colspan="1">0/27 (G1) 0/25 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">7/NM</td><td align="left" rowspan="1" colspan="1">8–12 weeks</td><td align="left" rowspan="1" colspan="1">Anodically oxidized (NobelDirect, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of a surgical guide (G1 and G2)</td></tr><tr><td align="left" rowspan="1" colspan="1">Al-Juboori et al. <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">9 (split-mouth design)</td><td align="left" rowspan="1" colspan="1">27–62 (50)</td><td align="left" rowspan="1" colspan="1">6 and 12 weeks</td><td align="left" rowspan="1" colspan="1">0/11 (G1) 0/11 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">Before surgery/before surgery</td><td align="left" rowspan="1" colspan="1">The implants were not loaded</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (SLA, Straumann, Basel, Switzerland)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide</td></tr><tr><td align="left" rowspan="1" colspan="1">Katsoulis et al. <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">40 (17, G1; 23, G2)</td><td align="left" rowspan="1" colspan="1">47–78 (61±9)</td><td align="left" rowspan="1" colspan="1">1 week 3 months</td><td align="left" rowspan="1" colspan="1">0/85 (G1) 0/110 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">5/unknown number of days</td><td align="left" rowspan="1" colspan="1">The implants were not loaded</td><td align="left" rowspan="1" colspan="1">Oxidized (NobelReplace Select Tapered, Nobel Biocare, Göteborg, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of a stereolithographic surgical guide (G1), 3 patients were light smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Marcelis et al. <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">29 (NM)</td><td align="left" rowspan="1" colspan="1">NM (48.7±16.4)</td><td align="left" rowspan="1" colspan="1">1 year of functional loading</td><td align="left" rowspan="1" colspan="1">0/16 (G1) 1/18 (G2) <xref ref-type="table-fn" rid="nt105">d</xref></td><td align="left" rowspan="1" colspan="1">0 (G1) 5.6 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">Immediate (n = 9) 2–3 months (n = 24) ≥ 6 months (n = 1)</td><td align="left" rowspan="1" colspan="1">Sandblasted + fluoride (Osseospeed, AstraTech, Mölndal, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Use of a surgical guide (G1 and G2), 3 patients were smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Sunitha and Sapthagiri <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref></td><td align="left" rowspan="1" colspan="1">2013</td><td align="left" rowspan="1" colspan="1">40 (20, G1; 20, G2)</td><td align="left" rowspan="1" colspan="1">25–62 (39±4)</td><td align="left" rowspan="1" colspan="1">1 week, 3 and 6 months, 1 and 2 years</td><td align="left" rowspan="1" colspan="1">0/20 (G1) 0/20 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">5/NP</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide No smokers</td></tr><tr><td align="left" rowspan="1" colspan="1">Tsoukaki et al. <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref></td><td align="left" rowspan="1" colspan="1">2013</td><td align="left" rowspan="1" colspan="1">20 (10, G1; 10, G2)</td><td align="left" rowspan="1" colspan="1">30–62 (47)</td><td align="left" rowspan="1" colspan="1">1, 2, 6, and 12 weeks</td><td align="left" rowspan="1" colspan="1">0/15 (G1) 0/15 (G2)</td><td align="left" rowspan="1" colspan="1">0 (G1) 0 (G2))</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">4/15</td><td align="left" rowspan="1" colspan="1">The implants were not loaded</td><td align="left" rowspan="1" colspan="1">Sandblasted + fluoride (Osseospeed, Astra Tech Dental, Mölndal, Sweden)</td><td align="left" rowspan="1" colspan="1">NP</td><td align="left" rowspan="1" colspan="1">Nonsubmerged implants, use of surgical guides (G1 and G2), heavy smokers (>10 cigarettes/day) were excluded</td></tr><tr><td align="left" rowspan="1" colspan="1">Meizi et al. <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref></td><td align="left" rowspan="1" colspan="1">2014</td><td align="left" rowspan="1" colspan="1">155 (NM)</td><td align="left" rowspan="1" colspan="1">NM (47.5)</td><td align="left" rowspan="1" colspan="1">3–9 months</td><td align="left" rowspan="1" colspan="1">7/237 (G1) 3/107 (G2)</td><td align="left" rowspan="1" colspan="1">2.95 (G1) 2.80 (G2)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">5/NM</td><td align="left" rowspan="1" colspan="1">Immediate (155, G1; 29, G2) 3–6 months (160)</td><td align="left" rowspan="1" colspan="1">Sandblasted and acid-etched (Saturn, Cortex Dental, Shlomi, Israel)</td><td align="left" rowspan="1" colspan="1">NM</td><td align="left" rowspan="1" colspan="1">No use of a surgical guide, 7% of the patients were diabetics, and 8% were smokers, 215 implants in fresh extraction sockets</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="nt101"><label></label><p>NM – not mentioned; G1 – group flapless surgery; G2 – group conventional flapped surgery; NP – not performed</p></fn><fn id="nt102"><label>a</label><p>The total of patients does not equal 169 because of cases treated with both protocols or in two phases of treatment in different years.</p></fn><fn id="nt103"><label>b</label><p>Unpublished information concerning the number of failed implants in each group was obtained by personal communication with one of the authors. In this case 3 implants were lost in the flapless group at the 6-month follow-up</p></fn><fn id="nt104"><label>c</label><p>There were 60 patients at the beginning of the study, but only 52 completed the study with 1 year of follow-up</p></fn><fn id="nt105"><label>d</label><p>Unpublished information concerning the number of failed implants in each group was obtained by personal communication with one of the authors.</p></fn></table-wrap-foot></table-wrap><p>All studies but one <xref rid="pone.0100624-Danza1" ref-type="bibr">[26]</xref> with available data of patients' age included only adult patients. Three split-mouth design studies were performed <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>. Eight studies <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref>, <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref>, <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref>–<xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref> made use of surgical guides when inserting implants through the flapless surgical technique, five studies <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>, <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref> used the surgical guides in both groups, whereas in ten studies <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>–<xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>, <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref>, <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref>, <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> the implants were inserted without any kind of surgical guide.</p><p>Not every article provided information about the number of failed implants or to which group the failed implants belonged to. Unpublished information concerning the number of failed implants in each group was obtained by personal communication with one of the authors in two studies <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>. From the 23 studies, a total of 1648 implants were placed through the flapless technique, with 51 failures (3.09%), and 1848 implants were placed through an open flap surgery, with 32 failures (1.73%). Nine studies <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>–<xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref>, <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>, <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref>, <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref> did not inform whether there was a statistically significant difference or not between the techniques concerning implant failure, whereas the other six studies <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref>, <xref rid="pone.0100624-Danza1" ref-type="bibr">[26]</xref>–<xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> did not find statistically significant difference. There were no implant failures in eight studies <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>, <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>–<xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref>, <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref>.</p><p>Thirteen articles <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>–<xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>–<xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref> did not report the incidence of postoperative infection. From the ten studies <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>, <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>–<xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref>, <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> that provided this information, it was observed 3 occurrences of infection in 265 patients receiving implants through the flapless technique (1.1%), and 3 episodes of postoperative infection in 252 patients receiving implants through the open flap surgery (1.2%).</p></sec><sec id="s3c"><title>Quality Assessment</title><p>Each trial was assessed for risk of bias, and the scores are summarized in <xref ref-type="table" rid="pone-0100624-t002">Table 2</xref>. Sixteen studies were judged to be at high risk of bias <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>, <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref>–<xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref>, whereas two studies were considered of moderate risk of bias <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, and five studies of low risk of bias <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>, <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>–<xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref>.</p><table-wrap id="pone-0100624-t002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.t002</object-id><label>Table 2</label><caption><title>Results of quality assessment.</title></caption><alternatives><graphic id="pone-0100624-t002-2" xlink:href="pone.0100624.t002"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col><col align="center" span="1"></col></colgroup><thead><tr><td align="left" rowspan="1" colspan="1">Authors</td><td align="left" rowspan="1" colspan="1">Published</td><td align="left" rowspan="1" colspan="1">Sequence generation (randomized?)</td><td align="left" rowspan="1" colspan="1">Allocation concealment</td><td align="left" rowspan="1" colspan="1">Incomplete outcome data addressed</td><td align="left" rowspan="1" colspan="1">Blinding</td><td align="left" rowspan="1" colspan="1">Estimated potential risk of bias</td></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1">Kinsel and Liss <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Nkenke et al. <xref rid="pone.0100624-Nkenke1" ref-type="bibr">[18]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Ozan et al. <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Unclear</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Unclear</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Villa and Rangert <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref></td><td align="left" rowspan="1" colspan="1">2007</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Cannizzaro et al. <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Moderate</td></tr><tr><td align="left" rowspan="1" colspan="1">Covani et al. <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Unclear</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Maló and Nobre <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Sennerby et al. <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref></td><td align="left" rowspan="1" colspan="1">2008</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Danza et al. <xref rid="pone.0100624-Danza1" ref-type="bibr">[26]</xref></td><td align="left" rowspan="1" colspan="1">2009</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Arisan et al. <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Berdougo et al. <xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Lindeboom and van Wijk <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate<xref ref-type="table-fn" rid="nt106">*</xref></td><td align="left" rowspan="1" colspan="1">Yes<xref ref-type="table-fn" rid="nt106">*</xref></td><td align="left" rowspan="1" colspan="1">Yes<xref ref-type="table-fn" rid="nt106">*</xref></td><td align="left" rowspan="1" colspan="1">Low</td></tr><tr><td align="left" rowspan="1" colspan="1">Rousseau <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Van de Velde et al. <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref></td><td align="left" rowspan="1" colspan="1">2010</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Low</td></tr><tr><td align="left" rowspan="1" colspan="1">Cannizzaro et al. <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Low</td></tr><tr><td align="left" rowspan="1" colspan="1">De Bruyn et al. <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Froum et al. <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref></td><td align="left" rowspan="1" colspan="1">2011</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Unclear</td><td align="left" rowspan="1" colspan="1">Moderate</td></tr><tr><td align="left" rowspan="1" colspan="1">Al-Juboori et al. <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes<xref ref-type="table-fn" rid="nt106">*</xref></td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Katsoulis et al. <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Marcelis et al. <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref></td><td align="left" rowspan="1" colspan="1">2012</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr><tr><td align="left" rowspan="1" colspan="1">Sunitha and Sapthagiri <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref></td><td align="left" rowspan="1" colspan="1">2013</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Low</td></tr><tr><td align="left" rowspan="1" colspan="1">Tsoukaki et al. <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref></td><td align="left" rowspan="1" colspan="1">2013</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Adequate</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Yes</td><td align="left" rowspan="1" colspan="1">Low</td></tr><tr><td align="left" rowspan="1" colspan="1">Meizi et al. <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref></td><td align="left" rowspan="1" colspan="1">2014</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">Inadequate</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">No</td><td align="left" rowspan="1" colspan="1">High</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="nt106"><label></label><p>* Unpublished information was obtained by personal communication with one of the authors.</p></fn></table-wrap-foot></table-wrap></sec><sec id="s3d"><title>Meta-analysis</title><p>In this study, a fixed-effects model was used to evaluate the implant failure, since statistically significant heterogeneity was not found (<italic>P</italic> = 0.86; I<sup>2</sup> = 0%). The fixed-effects model was also used when the postoperative infection outcomes were evaluated, because statistically significant heterogeneity was also not found (<italic>P</italic> = 0.58; I<sup>2</sup> = 0%).</p><p>The test for overall effect showed that the difference between the procedures (flapless vs. flapped) statistically affected the implant failure rates (<italic>P</italic> = 0.03; <xref ref-type="fig" rid="pone-0100624-g002">Figure 2</xref>). A RR of 1.75 (95% CI 1.07–2.86) for the use of flapless surgery implies that failures when implants are inserted by the flapless surgery are 1.75 times likely to happen than failures when implants are inserted by the open flap technique. Thus, the relative risk reduction (RRR) is −75%. In other words, being the RRR negative, the insertion of implants by the flapless surgery increases the risk of implant failure by 75%. Since the RR could differ depending on the risk of bias of the studies, a sensitivity analysis was performed. The RR was examined for the groups of studies of low and high risk of bias. The reasons to not include studies of moderate risk of bias was that there were only two studies <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, and no events were observed in both. When all low risk of bias studies were pooled, a RR of 1.84 resulted (95% CI 0.44–7.77; <italic>P</italic> = 0.49; I<sup>2</sup> = 0%), whereas when all high risk of bias studies were pooled, a RR of 1.73 was observed (95% CI 1.03–2.93; <italic>P</italic> = 0.04; I<sup>2</sup> = 0%).</p><fig id="pone-0100624-g002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g002</object-id><label>Figure 2</label><caption><title>Forest plot of comparison of flapless versus open flap surgery for the event ‘implant failure’.</title></caption><graphic xlink:href="pone.0100624.g002"></graphic></fig><p>On the other side, the meta-analysis showed that there are no apparent significant effects of flapless surgery on the occurrence of postoperative infection in patients receiving implants (RR 0.96, 95% CI 0.23–4.03; <italic>P</italic> = 0.960; <xref ref-type="fig" rid="pone-0100624-g003">Figure 3</xref>).</p><fig id="pone-0100624-g003" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g003</object-id><label>Figure 3</label><caption><title>Forest plot of comparison of flapless versus open flap surgery for the event ‘postoperative infection’.</title></caption><graphic xlink:href="pone.0100624.g003"></graphic></fig><p>Fifteen studies (1360 implants) provided information about the marginal bone loss with standard deviation, necessary for the calculation of comparisons in continuous outcomes (<xref ref-type="fig" rid="pone-0100624-g004">Figure 4</xref>). A random-effects model was used to evaluate the marginal bone loss, since statistically significant heterogeneity was found (<italic>P</italic> = 0.0002; I<sup>2</sup> = 66%). There was no statistically significant difference (<italic>P</italic> = 0.16) between the different techniques concerning the marginal bone loss.</p><fig id="pone-0100624-g004" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g004</object-id><label>Figure 4</label><caption><title>Forest plot of comparison of immediate nonfunctional versus immediate functional loading for the event ‘marginal bone loss’ (values in millimeters).</title></caption><graphic xlink:href="pone.0100624.g004"></graphic></fig></sec><sec id="s3e"><title>Publication bias</title><p>The funnel plots did not show asymmetry when the studies reporting either the outcome ‘implant failure’ (<xref ref-type="fig" rid="pone-0100624-g005">Figure 5</xref>), ‘postoperative infection’ (<xref ref-type="fig" rid="pone-0100624-g006">Figure 6</xref>), or ‘marginal bone loss’ (<xref ref-type="fig" rid="pone-0100624-g007">Figure 7</xref>) are analyzed, indicating absence of publication bias.</p><fig id="pone-0100624-g005" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g005</object-id><label>Figure 5</label><caption><title>Funnel plot for the studies reporting the outcome event ‘implant failure’.</title></caption><graphic xlink:href="pone.0100624.g005"></graphic></fig><fig id="pone-0100624-g006" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g006</object-id><label>Figure 6</label><caption><title>Funnel plot for the studies reporting the outcome event ‘postoperative infection’.</title></caption><graphic xlink:href="pone.0100624.g006"></graphic></fig><fig id="pone-0100624-g007" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0100624.g007</object-id><label>Figure 7</label><caption><title>Funnel plot for the studies reporting the outcome event ‘marginal bone loss’.</title></caption><graphic xlink:href="pone.0100624.g007"></graphic></fig></sec></sec><sec id="s4"><title>Discussion</title><p>Potential biases are likely to be greater for non-randomized studies compared with RCTs, so results should always be interpreted with caution when they are included in reviews and meta-analyses <xref rid="pone.0100624-Higgins1" ref-type="bibr">[8]</xref>. However, narrowing the inclusion criteria increases homogeneity but also excludes the results of more trials and thus risks the exclusion of significant data <xref rid="pone.0100624-Shrier1" ref-type="bibr">[29]</xref>. This was the reason to include non-randomized studies in the present meta-analysis. The issue is important because meta-analyses are frequently conducted on a limited number of RCTs. In meta-analyses such as these, adding more information from observational studies may aid in clinical reasoning and establish a more solid foundation for causal inferences <xref rid="pone.0100624-Shrier1" ref-type="bibr">[29]</xref>.</p><p>The relevant question is whether the lack of a difference between the flapless and the open flap implant procedures in some studies concerning implant failure rates is a real finding or is due to the lack of statistical power, given the small number of patients per group in many studies <xref rid="pone.0100624-Ozan1" ref-type="bibr">[1]</xref>, <xref rid="pone.0100624-Sunitha1" ref-type="bibr">[4]</xref>, <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Froum1" ref-type="bibr">[15]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>–<xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Marcelis1" ref-type="bibr">[22]</xref>, <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref>. However, there was a statistically and clinically significant difference (<italic>P</italic> = 0.03) favoring the open flap surgery was found after the meta-analyses, stressing the importance of meta-analyses to increase sample size of individual trials to reach more precise estimates of the effects of interventions. However, when studies of low and high risk of bias were pooled separately, there was a difference in the results and in the statistical significance of the RR. Thus, the results must be interpreted carefully.</p><p>One drawback found in six studies <xref rid="pone.0100624-Arisan1" ref-type="bibr">[3]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>, <xref rid="pone.0100624-AlJuboori1" ref-type="bibr">[16]</xref>, <xref rid="pone.0100624-Tsoukaki1" ref-type="bibr">[17]</xref>, <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref> is the fact that the patients were followed for a short period (1–6 months). Thus, only early failures could be assessed. A longer follow-up period can lead to an increase in the failure rate, especially if it extended beyond functional loading, because other prosthetic factors can influence implant failure from that point onward <xref rid="pone.0100624-Sharaf1" ref-type="bibr">[30]</xref>. The success of a dental implant should be defined after a minimal period of 12 months of implant loading. Early, intermediate, and long-term success has been suggested to span 1 to 3 years, 3 to 7 years, and more than 7 years respectively <xref rid="pone.0100624-tenBruggenkate1" ref-type="bibr">[31]</xref>. Moreover, the results found in the studies differed from each other, and this difference could be due to factors such as differences in the patients included in the study or the clinicians placing and restoring the implants.</p><p>The immediate loading only in the flapless group in some studies <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref> is a confounding factor, as well as the presence of smokers among the patients in several trials <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Cannizzaro1" ref-type="bibr">[10]</xref>, <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref>–<xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref>, <xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref>, the use of grafts <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-Kinsel1" ref-type="bibr">[24]</xref>, <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref>, the use or not use of surgical guides, different prosthetic configurations, and the insertion of implants from different brands and surface treatments. Titanium with different surface modifications shows a wide range of chemical, physical properties, and surface topographies or morphologies, depending on how they are prepared and handled <xref rid="pone.0100624-Chrcanovic2" ref-type="bibr">[32]</xref>–<xref rid="pone.0100624-Chrcanovic4" ref-type="bibr">[34]</xref>, and it is not clear whether, in general, one surface modification is better than another <xref rid="pone.0100624-Wennerberg1" ref-type="bibr">[35]</xref>. Also, there is the fact that some studies inserted some <xref rid="pone.0100624-Cannizzaro2" ref-type="bibr">[14]</xref>, <xref rid="pone.0100624-Meizi1" ref-type="bibr">[23]</xref>, <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref> or all implants in fresh extraction sockets <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref>. One of these studies <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref> placed all implants in infected extraction sockets. Moreover, in four studies <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Villa1" ref-type="bibr">[19]</xref>, <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> flapless surgery was only considered in favorable clinical conditions. Flapless surgery was considered a treatment option based on clinical examination and largely depending on the anatomical condition of the bone after clinical and radiographic inspection. Therefore, the allocation to the surgical approach was biased (selection bias), what could have masked substantial intergroup disparity.</p><p>Currently, some software systems using computed tomography scans have been proposed to aid in planning surgery and to produce surgical drilling guides to transfer the planned position to the surgical field. These guides are manufactured in such a way that they match the location, trajectory, and depth of the planned implant with a high degree of precision. As the dental practitioner places the implants, the guides stabilize the drilling by restricting the degrees of freedom of the drill trajectory and depth <xref rid="pone.0100624-Chrcanovic5" ref-type="bibr">[36]</xref>. It was stated that by using computer-assisted surgery predictability, precision and safety in flapless dental implantology are ensured <xref rid="pone.0100624-Lindeboom1" ref-type="bibr">[12]</xref>.</p><p>However, the precision of the whole procedure depends largely on the ability to position accurately the drill guide, and to maintain that stable position during the whole procedure <xref rid="pone.0100624-Chrcanovic5" ref-type="bibr">[36]</xref>. In the case of the placement of implants in completely edentulous jaws, there must be a way to assure the stability of the drill guide, and this is done by fixing the surgical guide onto the bone by osteosynthesis screws. Asymmetric distribution of the screws or uneven tightening of the screws could bring the drilling template out of balance. Furthermore, a certain error is induced as the diameter of the steel tubes is slightly larger than the drill diameter <xref rid="pone.0100624-Chrcanovic5" ref-type="bibr">[36]</xref>. Finally, the largest error is probably due to the fact that the final step in the procedure is carried out manually, depending on the surgical guide used. In these cases, implant placement cannot be done through the surgical drill guide because of present mechanical limitations. The drill guide, therefore, has to be removed before the implant is actually inserted, leaving the possibility of additional deviation <xref rid="pone.0100624-Chrcanovic5" ref-type="bibr">[36]</xref>. Because of these reasons, the surgical drill guide may provide a false security in decreasing the risk of bone fenestrations or perforations. This may be one of the reasons why it was observed, in the present review, a higher percentage of implant failures with the flapless technique when compared with the open flap surgery.</p><p>Still concerning the precision of the implant insertion, it is worth commenting about the technique used by the study of Sennerby et al. <xref rid="pone.0100624-Sennerby1" ref-type="bibr">[25]</xref>. They made use of a slide-over guide sleeve to evaluate and determine the position of the implant. This system is based on the surgeons' imprecise opinion of what is the exact direction of the implants to be placed and it is subjected to flaws, which may have led to an increasing incidence of implant bone plate fenestrations or perforations, and consequently higher implant failure in this group (7.9% versus no failure in the open flap surgery). Correct bur angulation is critical in the procedure <xref rid="pone.0100624-Chrcanovic5" ref-type="bibr">[36]</xref>. With the CT-guide surgery, it is possible to verify in advance the presence of concavities of the vestibular and lingual/palatal bone plates surrounding the planned implant surgical site, thus planning the correct bur angulation and decreasing the chance of implant bone fenestrations or perforations.</p><p>Moreover, one <italic>in vitro</italic> study <xref rid="pone.0100624-VandeVelde2" ref-type="bibr">[37]</xref> analyzed deviations in position and inclination of implants placed with flapless surgery compared with the ideally planned position and examined whether the outcome was affected by the experience level. The authors observed that the three-dimensional location of implants installed with flapless approach differed significantly from the ideal, although neighboring teeth were present and maximal radiographical information was available, and the outcome was not influenced by the level of experience with implant surgery. It was suggested that these deviations would in a clinical situation lead to complications such as loss of implant stability, aesthetical and phonetical consequences. The authors recommended the performance of more precise measurements of soft tissue <italic>in situ</italic> or additional use of guiding systems.</p><p>Since flapless implant placement generally is a “blind” surgical technique, care must be taken when placing implants. Angulation of the implants affected by drilling is critical so as to avoid perforation of the cortical plates, both lingual and buccal, especially on the lingual in the mandibular molar area and the anterior maxilla <xref rid="pone.0100624-Campelo1" ref-type="bibr">[38]</xref>. Therefore, the surgeon must weigh the benefits of the flapless technique in front of the increasing risk of implant bone fenestrations or perforations, which allegedly may impair implant success or increase the implant failure rates <xref rid="pone.0100624-Chiapasco1" ref-type="bibr">[39]</xref>. Violation of the dental implant beyond the alveolar housing may result in infection and ultimate loss of the implant <xref rid="pone.0100624-Annibali1" ref-type="bibr">[40]</xref>. There should be no problem if the patient has been appropriately selected and an appropriate width of bone is available for implant placement <xref rid="pone.0100624-Campelo1" ref-type="bibr">[38]</xref>. Some authors <xref rid="pone.0100624-Campelo1" ref-type="bibr">[38]</xref> suggested a minimum of 7 mm of bone width and substantial training to use the appropriate technique.</p><p>Another hypothetical drawback of the flapless procedure is that it could interfere with osseointegration because of implant surface contamination and the deposition of epithelial and connective cells from the oral mucosa in the bone during surgical preparation <xref rid="pone.0100624-Berdougo1" ref-type="bibr">[27]</xref>.</p><p>On the other hand, a flapless procedure could have a positive effect on the early bone remodeling process, because during the surgical procedure, the bone remains covered by the periosteum. However, the strongly tightened surgical template used in to insert implants in totally edentulous jaws may hinder access of saline water and proper cooling during the drilling procedure, which could negatively influence the implant surrounding the bone and the remodeling process during healing <xref rid="pone.0100624-Katsoulis1" ref-type="bibr">[21]</xref>.</p><p>Concerning the marginal bone loss, one may expect that the open flap surgery may cause higher marginal bone loss due to decreased supraperiosteal blood supply because of the raising the tissue flap during the surgical procedure. Studies have demonstrated that flap reflection often results in bone resorption around natural teeth <xref rid="pone.0100624-Wood1" ref-type="bibr">[41]</xref>. However, it was showed in five studies that the flapless technique generated more marginal bone loss around the implants <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref>, <xref rid="pone.0100624-Covani1" ref-type="bibr">[11]</xref>, <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref>, <xref rid="pone.0100624-Mal1" ref-type="bibr">[20]</xref>, <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref>. The authors of some of the articles here reviewed provided some reasonable explanations for this. De Bruyn et al. <xref rid="pone.0100624-DeBruyn1" ref-type="bibr">[5]</xref> suggested that this was probably caused in their study due to overdoing of the countersinking procedure. More extensive widening of the crestal bone was necessary to remove enough bone as to allow proper placement of the healing abutment. By countersinking wider and deeper, the coronal portion of the implant is not always in intimate contact with the bone. In the flapped sites, the countersinking procedure was more controlled according to the guidelines of the manufacturer because visual inspection <italic>in situ</italic> was possible. Rousseau <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref> discussed that this is due to implants being installed blindly, and thus implants are installed more deeply with the flapless technique than with the open flap technique. Therefore, a portion of the transmucosal (supracrestal) part of the implant is slightly below the crestal bone level. Because the coronal part of the implant is smooth titanium, rearrangement of bone around the neck of the implant is normal. When an open flap technique is used, the implant is installed under visual control directly at the right crestal bone position. This results in less bone rearrangement around the implant neck <xref rid="pone.0100624-Rousseau1" ref-type="bibr">[28]</xref>. The results found in the study of Van de Velde et al. <xref rid="pone.0100624-VandeVelde1" ref-type="bibr">[13]</xref> may be related to the fact that the implants inserted through the flapless technique were immediately loaded, whereas the implants inserted through open flap surgery were loaded only after 6 weeks.</p><p>The results of the present study have to be interpreted with caution because of its limitations. First of all, all confounding factors may have affected the long-term outcomes and not just the use of flapless or open flap surgery, and the impact of these variables on the implant survival rate, postoperative infection and marginal bone loss is difficult to estimate if these factors are not identified separately between the two different procedures in order to perform a meta-regression analysis. The lack of control of the confounding factors limited the potential to draw robust conclusions. Second, some of the included studies had a retrospective design, and the nature of a retrospective study inherently results in flaws. These problems were manifested by the gaps in information and incomplete records. Furthermore, all data rely on the accuracy of the original examination and documentation. Items may have been excluded in the initial examination or not recorded in the medical chart <xref rid="pone.0100624-Chrcanovic6" ref-type="bibr">[42]</xref>, <xref rid="pone.0100624-Chrcanovic7" ref-type="bibr">[43]</xref>.</p><p>The authors of the present study believe that, for a more definite conclusion, future double-blinded RCTs with larger patient samples are required to determine the real effect of flapless implant surgery on patient outcome variables.</p></sec><sec id="s5"><title>Conclusion</title><p>The difference between the procedures (flapless vs. flapped) statistically affected the implant failure rates. However, the results must be interpreted carefully, as a sensitivity analysis revealed differences when the groups of studies of high and low risk of bias were pooled separately. No statistically significant effects of open flap surgery or flapless surgery on the occurrence of postoperative infection and on the marginal bone loss were observed.</p></sec><sec sec-type="supplementary-material" id="s6"><title>Supporting Information</title><supplementary-material content-type="local-data" id="pone.0100624.s001"><label>Checklist S1</label><caption><p><bold>PRISMA checklist.</bold></p><p>(PDF)</p></caption><media xlink:href="pone.0100624.s001.pdf"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material></sec></body><back><ack><p>The authors would like to thank Dr. Mohammed Jasim Al-Juboori, Dr. Georgios Romanos, and Dr. Miguel de Araújo Nobre, for having sent us their articles, and Dr. Jerome A. Lindeboom, Dr. Ignace Naert, and Dr. Wim Teughels, who provided us some missing information about their studies.</p></ack><ref-list><title>References</title><ref id="pone.0100624-Ozan1"><label>1</label><mixed-citation publication-type="journal"><name><surname>Ozan</surname><given-names>O</given-names></name>, <name><surname>Turkyilmaz</surname><given-names>I</given-names></name>, <name><surname>Yilmaz</surname><given-names>B</given-names></name> (<year>2007</year>) <article-title>A preliminary report of patients treated with early loaded implants using computerized tomography-guided surgical stents: flapless versus conventional flapped surgery</article-title>. <source>J Oral Rehabil</source><volume>34</volume>: <fpage>835</fpage>–<lpage>840</lpage>.<pub-id pub-id-type="pmid">17919250</pub-id></mixed-citation></ref><ref id="pone.0100624-Rocci1"><label>2</label><mixed-citation publication-type="journal"><name><surname>Rocci</surname><given-names>A</given-names></name>, <name><surname>Martignoni</surname><given-names>M</given-names></name>, <name><surname>Gottlow</surname><given-names>J</given-names></name> (<year>2003</year>) <article-title>Immediate loading in the maxilla using flapless surgery, implants placed in predetermined positions, and prefabricated provisional restorations: a retrospective 3-year clinical study</article-title>. <source>Clin Implant Dent Relat Res</source><volume>5(Suppl</volume> (<issue>)</issue>) <fpage>29</fpage>–<lpage>36</lpage>.<pub-id pub-id-type="pmid">12691648</pub-id></mixed-citation></ref><ref id="pone.0100624-Arisan1"><label>3</label><mixed-citation publication-type="journal"><name><surname>Arisan</surname><given-names>V</given-names></name>, <name><surname>Karabuda</surname><given-names>CZ</given-names></name>, <name><surname>Ozdemir</surname><given-names>T</given-names></name> (<year>2010</year>) <article-title>Implant surgery using bone- and mucosa-supported stereolithographic guides in totally edentulous jaws: surgical and post-operative outcomes of computer-aided vs. standard techniques</article-title>. <source>Clin Oral Implants Res</source><volume>21</volume>: <fpage>980</fpage>–<lpage>988</lpage>.<pub-id pub-id-type="pmid">20497439</pub-id></mixed-citation></ref><ref id="pone.0100624-Sunitha1"><label>4</label><mixed-citation publication-type="journal"><name><surname>Sunitha</surname><given-names>RV</given-names></name>, <name><surname>Sapthagiri</surname><given-names>E</given-names></name> (<year>2013</year>) <article-title>Flapless implant surgery: a 2-year follow-up study of 40 implants</article-title>. <source>Oral Surg Oral Med Oral Pathol Oral Radiol</source><volume>116</volume>: <fpage>e237</fpage>–<lpage>e243</lpage>.<pub-id pub-id-type="pmid">22819332</pub-id></mixed-citation></ref><ref id="pone.0100624-DeBruyn1"><label>5</label><mixed-citation publication-type="journal"><name><surname>De Bruyn</surname><given-names>H</given-names></name>, <name><surname>Atashkadeh</surname><given-names>M</given-names></name>, <name><surname>Cosyn</surname><given-names>J</given-names></name>, <name><surname>van de Velde</surname><given-names>T</given-names></name> (<year>2011</year>) <article-title>Clinical outcome and bone preservation of single TiUnit implants installed with flapless or flap surgery</article-title>. <source>Clin Implant Dent Relat Res</source><volume>13</volume>: <fpage>175</fpage>–<lpage>183</lpage>.<pub-id pub-id-type="pmid">19744199</pub-id></mixed-citation></ref><ref id="pone.0100624-Chrcanovic1"><label>6</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Albrektsson</surname><given-names>T</given-names></name>, <name><surname>Wennerberg</surname><given-names>A</given-names></name> (<year>2014</year>) <article-title>Reasons for failures of oral implants</article-title>. <source>J Oral Rehabil</source><volume>41</volume>: <fpage>443</fpage>–<lpage>476</lpage>.<pub-id pub-id-type="pmid">24612346</pub-id></mixed-citation></ref><ref id="pone.0100624-Moher1"><label>7</label><mixed-citation publication-type="other">Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Ann Intern Med 151: 264–269, W64.</mixed-citation></ref><ref id="pone.0100624-Higgins1"><label>8</label><mixed-citation publication-type="other">Higgins JPT, Green S (2011) Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. [updated March 2011]. The Cochrane Collaboration. Available: <ext-link ext-link-type="uri" xlink:href="http://www.cochrane-handbook.org">http://www.cochrane-handbook.org</ext-link>. Accessed 2014 Mar 3.</mixed-citation></ref><ref id="pone.0100624-Egger1"><label>9</label><mixed-citation publication-type="other">Egger M, Smith GD (2003) Principles of and procedures for systematic reviews. In: Egger M, Smith GD, Altman DG (eds). Systematic Reviews in Health Care: Meta-analysis in Context. London: BMJ books. 23–42.</mixed-citation></ref><ref id="pone.0100624-Cannizzaro1"><label>10</label><mixed-citation publication-type="journal"><name><surname>Cannizzaro</surname><given-names>G</given-names></name>, <name><surname>Leone</surname><given-names>M</given-names></name>, <name><surname>Consolo</surname><given-names>U</given-names></name>, <name><surname>Ferri</surname><given-names>V</given-names></name>, <name><surname>Esposito</surname><given-names>M</given-names></name> (<year>2008</year>) <article-title>Immediate functional loading of implants placed with flapless surgery versus conventional implants in partially edentulous patients: a 3-year randomized controlled clinical trial</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>23</volume>: <fpage>867</fpage>–<lpage>875</lpage>.<pub-id pub-id-type="pmid">19014156</pub-id></mixed-citation></ref><ref id="pone.0100624-Covani1"><label>11</label><mixed-citation publication-type="journal"><name><surname>Covani</surname><given-names>U</given-names></name>, <name><surname>Cornelini</surname><given-names>R</given-names></name>, <name><surname>Barone</surname><given-names>A</given-names></name> (<year>2008</year>) <article-title>Buccal bone augmentation around immediate implants with and without flap elevation: a modified approach</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>23</volume>: <fpage>841</fpage>–<lpage>846</lpage>.<pub-id pub-id-type="pmid">19014153</pub-id></mixed-citation></ref><ref id="pone.0100624-Lindeboom1"><label>12</label><mixed-citation publication-type="journal"><name><surname>Lindeboom</surname><given-names>JA</given-names></name>, <name><surname>van Wijk</surname><given-names>AJ</given-names></name> (<year>2010</year>) <article-title>A comparison of two implant techniques on patient-based outcome measures: a report of flapless vs. conventional flapped implant placement</article-title>. <source>Clin Oral Implants Res</source><volume>21</volume>: <fpage>366</fpage>–<lpage>370</lpage>.<pub-id pub-id-type="pmid">20128828</pub-id></mixed-citation></ref><ref id="pone.0100624-VandeVelde1"><label>13</label><mixed-citation publication-type="journal"><name><surname>Van de Velde</surname><given-names>T</given-names></name>, <name><surname>Sennerby</surname><given-names>L</given-names></name>, <name><surname>De Bruyn</surname><given-names>H</given-names></name> (<year>2010</year>) <article-title>The clinical and radiographic outcome of implants placed in the posterior maxilla with a guided flapless approach and immediately restored with a provisional rehabilitation: a randomized clinical trial</article-title>. <source>Clin Oral Implants Res</source><volume>21</volume>: <fpage>1223</fpage>–<lpage>1233</lpage>.<pub-id pub-id-type="pmid">20626424</pub-id></mixed-citation></ref><ref id="pone.0100624-Cannizzaro2"><label>14</label><mixed-citation publication-type="journal"><name><surname>Cannizzaro</surname><given-names>G</given-names></name>, <name><surname>Felice</surname><given-names>P</given-names></name>, <name><surname>Leone</surname><given-names>M</given-names></name>, <name><surname>Checchi</surname><given-names>V</given-names></name>, <name><surname>Esposito</surname><given-names>M</given-names></name> (<year>2011</year>) <article-title>Flapless versus open flap implant surgery in partially edentulous patients subjected to immediate loading: 1-year results from a split-mouth randomised controlled trial</article-title>. <source>Eur J Oral Implantol</source><volume>4</volume>: <fpage>177</fpage>–<lpage>188</lpage>.<pub-id pub-id-type="pmid">22043463</pub-id></mixed-citation></ref><ref id="pone.0100624-Froum1"><label>15</label><mixed-citation publication-type="journal"><name><surname>Froum</surname><given-names>SJ</given-names></name>, <name><surname>Cho</surname><given-names>SC</given-names></name>, <name><surname>Elian</surname><given-names>N</given-names></name>, <name><surname>Romanos</surname><given-names>G</given-names></name>, <name><surname>Jalbout</surname><given-names>Z</given-names></name>, <etal>et al</etal> (<year>2011</year>) <article-title>Survival rate of one-piece dental implants placed with a flapless or flap protocol – a randomized, controlled study: 12-month results</article-title>. <source>Int J Periodontics Restorative Dent</source><volume>31</volume>: <fpage>591</fpage>–<lpage>601</lpage>.<pub-id pub-id-type="pmid">22140661</pub-id></mixed-citation></ref><ref id="pone.0100624-AlJuboori1"><label>16</label><mixed-citation publication-type="journal"><name><surname>Al-Juboori</surname><given-names>MJ</given-names></name>, <name><surname>Bin Abdulrahaman</surname><given-names>S</given-names></name>, <name><surname>Jassan</surname><given-names>A</given-names></name> (<year>2012</year>) <article-title>Comparison of flapless and conventional flap and the effect on crestal bone resorption during a 12-week healing period</article-title>. <source>Dent Implantol Update</source><volume>23</volume>: <fpage>9</fpage>–<lpage>16</lpage>.<pub-id pub-id-type="pmid">22338850</pub-id></mixed-citation></ref><ref id="pone.0100624-Tsoukaki1"><label>17</label><mixed-citation publication-type="journal"><name><surname>Tsoukaki</surname><given-names>M</given-names></name>, <name><surname>Kalpidis</surname><given-names>CD</given-names></name>, <name><surname>Sakellari</surname><given-names>D</given-names></name>, <name><surname>Tsalikis</surname><given-names>L</given-names></name>, <name><surname>Mikrogiorgis</surname><given-names>G</given-names></name>, <etal>et al</etal> (<year>2013</year>) <article-title>Clinical, radiographic, microbiological, and immunological outcomes of flapped vs. flapless dental implants: a prospective randomized controlled clinical trial</article-title>. <source>Clin Oral Implants Res</source><volume>24</volume>: <fpage>969</fpage>–<lpage>976</lpage>.<pub-id pub-id-type="pmid">22708917</pub-id></mixed-citation></ref><ref id="pone.0100624-Nkenke1"><label>18</label><mixed-citation publication-type="journal"><name><surname>Nkenke</surname><given-names>E</given-names></name>, <name><surname>Eitner</surname><given-names>S</given-names></name>, <name><surname>Radespiel-Tröger</surname><given-names>M</given-names></name>, <name><surname>Vairaktaris</surname><given-names>E</given-names></name>, <name><surname>Neukam</surname><given-names>FW</given-names></name>, <etal>et al</etal> (<year>2007</year>) <article-title>Patient-centred outcomes comparing transmucosal implant placement with an open approach in the maxilla: a prospective, nonrandomized pilot study</article-title>. <source>Clin Oral Implants Res</source><volume>18</volume>: <fpage>197</fpage>–<lpage>203</lpage>.<pub-id pub-id-type="pmid">17348884</pub-id></mixed-citation></ref><ref id="pone.0100624-Villa1"><label>19</label><mixed-citation publication-type="journal"><name><surname>Villa</surname><given-names>R</given-names></name>, <name><surname>Rangert</surname><given-names>B</given-names></name> (<year>2007</year>) <article-title>Immediate and early function of implants placed in extraction sockets of maxillary infected teeth: A pilot study</article-title>. <source>J Prosthet Dent</source><volume>97</volume>: <fpage>S96</fpage>–<lpage>S108</lpage>.<pub-id pub-id-type="pmid">17618939</pub-id></mixed-citation></ref><ref id="pone.0100624-Mal1"><label>20</label><mixed-citation publication-type="journal"><name><surname>Maló</surname><given-names>P</given-names></name>, <name><surname>Nobre</surname><given-names>MD</given-names></name> (<year>2008</year>) <article-title>Flap vs. flapless surgical techniques at immediate implant function in predominantly soft bone for rehabilitation of partial edentulism: a prospective cohort study with follow-up of 1 year</article-title>. <source>Eur J Oral Implantol</source><volume>1</volume>: <fpage>293</fpage>–<lpage>304</lpage>.<pub-id pub-id-type="pmid">20467636</pub-id></mixed-citation></ref><ref id="pone.0100624-Katsoulis1"><label>21</label><mixed-citation publication-type="journal"><name><surname>Katsoulis</surname><given-names>J</given-names></name>, <name><surname>Avrampou</surname><given-names>M</given-names></name>, <name><surname>Spycher</surname><given-names>C</given-names></name>, <name><surname>Stipic</surname><given-names>M</given-names></name>, <name><surname>Enkling</surname><given-names>N</given-names></name>, <etal>et al</etal> (<year>2012</year>) <article-title>Comparison of implant stability by means of resonance frequency analysis for flapless and conventionally inserted implants</article-title>. <source>Clin Implant Dent Relat Res</source><volume>14</volume>: <fpage>915</fpage>–<lpage>923</lpage>.<pub-id pub-id-type="pmid">21414133</pub-id></mixed-citation></ref><ref id="pone.0100624-Marcelis1"><label>22</label><mixed-citation publication-type="journal"><name><surname>Marcelis</surname><given-names>K</given-names></name>, <name><surname>Vercruyssen</surname><given-names>M</given-names></name>, <name><surname>Naert</surname><given-names>I</given-names></name>, <name><surname>Teughels</surname><given-names>W</given-names></name>, <name><surname>Quirynen</surname><given-names>M</given-names></name> (<year>2012</year>) <article-title>Model-based guided implant insertion for solitary tooth replacement: a pilot study</article-title>. <source>Clin Oral Implants Res</source><volume>23</volume>: <fpage>999</fpage>–<lpage>1003</lpage>.<pub-id pub-id-type="pmid">21722195</pub-id></mixed-citation></ref><ref id="pone.0100624-Meizi1"><label>23</label><mixed-citation publication-type="journal"><name><surname>Meizi</surname><given-names>E</given-names></name>, <name><surname>Meir</surname><given-names>M</given-names></name>, <name><surname>Laster</surname><given-names>Z</given-names></name> (<year>2014</year>) <article-title>New-design dental implants: a 1-year prospective clinical study of 344 consecutively placed implants comparing immediate loading versus delayed loading and flapless versus full-thickness flap</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>29</volume>: <fpage>e14</fpage>–<lpage>e21</lpage>.<pub-id pub-id-type="pmid">24451883</pub-id></mixed-citation></ref><ref id="pone.0100624-Kinsel1"><label>24</label><mixed-citation publication-type="journal"><name><surname>Kinsel</surname><given-names>RP</given-names></name>, <name><surname>Liss</surname><given-names>M</given-names></name> (<year>2007</year>) <article-title>Retrospective analysis of 56 edentulous dental arches restored with 344 single-stage implants using an immediate loading fixed provisional protocol: statistical predictors of implant failure</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>22</volume>: <fpage>823</fpage>–<lpage>830</lpage>.<pub-id pub-id-type="pmid">17974119</pub-id></mixed-citation></ref><ref id="pone.0100624-Sennerby1"><label>25</label><mixed-citation publication-type="journal"><name><surname>Sennerby</surname><given-names>L</given-names></name>, <name><surname>Rocci</surname><given-names>A</given-names></name>, <name><surname>Becker</surname><given-names>W</given-names></name>, <name><surname>Jonsson</surname><given-names>L</given-names></name>, <name><surname>Johansson</surname><given-names>LA</given-names></name>, <etal>et al</etal> (<year>2008</year>) <article-title>Short-term clinical results of Nobel Direct implants: a retrospective multicentre analysis</article-title>. <source>Clin Oral Implant Res</source><volume>19</volume>: <fpage>219</fpage>–<lpage>226</lpage>.</mixed-citation></ref><ref id="pone.0100624-Danza1"><label>26</label><mixed-citation publication-type="journal"><name><surname>Danza</surname><given-names>M</given-names></name>, <name><surname>Zollin</surname><given-names>I</given-names></name>, <name><surname>Carinci</surname><given-names>F</given-names></name> (<year>2009</year>) <article-title>Comparison between implants inserted with and without computer planning and custom model coordination</article-title>. <source>J Craniofac Surg</source><volume>20</volume>: <fpage>1086</fpage>–<lpage>1092</lpage>.<pub-id pub-id-type="pmid">19521258</pub-id></mixed-citation></ref><ref id="pone.0100624-Berdougo1"><label>27</label><mixed-citation publication-type="journal"><name><surname>Berdougo</surname><given-names>M</given-names></name>, <name><surname>Fortin</surname><given-names>T</given-names></name>, <name><surname>Blanchet</surname><given-names>E</given-names></name>, <name><surname>Isidori</surname><given-names>M</given-names></name>, <name><surname>Bosson</surname><given-names>JL</given-names></name> (<year>2010</year>) <article-title>Flapless implant surgery using an image-guided system. A 1- to 4-year retrospective multicenter comparative clinical study</article-title>. <source>Clin Implant Dent Relat Res</source><volume>12</volume>: <fpage>142</fpage>–<lpage>152</lpage>.<pub-id pub-id-type="pmid">19220842</pub-id></mixed-citation></ref><ref id="pone.0100624-Rousseau1"><label>28</label><mixed-citation publication-type="journal"><name><surname>Rousseau</surname><given-names>P</given-names></name> (<year>2010</year>) <article-title>Flapless and traditional dental implant surgery: an open, retrospective comparative study</article-title>. <source>J Oral Maxillofac Surg</source><volume>68</volume>: <fpage>2299</fpage>–<lpage>2306</lpage>.<pub-id pub-id-type="pmid">20728034</pub-id></mixed-citation></ref><ref id="pone.0100624-Shrier1"><label>29</label><mixed-citation publication-type="journal"><name><surname>Shrier</surname><given-names>I</given-names></name>, <name><surname>Boivin</surname><given-names>JF</given-names></name>, <name><surname>Steele</surname><given-names>RJ</given-names></name>, <name><surname>Platt</surname><given-names>RW</given-names></name>, <name><surname>Furlan</surname><given-names>A</given-names></name>, <etal>et al</etal> (<year>2007</year>) <article-title>Should meta-analyses of interventions include observational studies in addition to randomized controlled trials? A critical examination of underlying principles</article-title>. <source>Am J Epidemiol</source><volume>166</volume>: <fpage>1203</fpage>–<lpage>1209</lpage>.<pub-id pub-id-type="pmid">17712019</pub-id></mixed-citation></ref><ref id="pone.0100624-Sharaf1"><label>30</label><mixed-citation publication-type="journal"><name><surname>Sharaf</surname><given-names>B</given-names></name>, <name><surname>Jandali-Rifai</surname><given-names>M</given-names></name>, <name><surname>Susarla</surname><given-names>SM</given-names></name>, <name><surname>Dodson</surname><given-names>TB</given-names></name> (<year>2011</year>) <article-title>Do perioperative antibiotics decrease implant failure?</article-title><source>J Oral Maxillofac Surg</source><volume>69</volume>: <fpage>2345</fpage>–<lpage>2350</lpage>.<pub-id pub-id-type="pmid">21676512</pub-id></mixed-citation></ref><ref id="pone.0100624-tenBruggenkate1"><label>31</label><mixed-citation publication-type="journal"><name><surname>ten Bruggenkate</surname><given-names>CM</given-names></name>, <name><surname>van der Kwast</surname><given-names>WA</given-names></name>, <name><surname>Oosterbeek</surname><given-names>HS</given-names></name> (<year>1990</year>) <article-title>Success criteria in oral implantology: A review of the literature</article-title>. <source>Int J Oral Implantol</source><volume>7</volume>: <fpage>45</fpage>–<lpage>51</lpage>.<pub-id pub-id-type="pmid">2103118</pub-id></mixed-citation></ref><ref id="pone.0100624-Chrcanovic2"><label>32</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Pedrosa</surname><given-names>AR</given-names></name>, <name><surname>Martins</surname><given-names>MD</given-names></name> (<year>2012</year>) <article-title>Chemical and topographic analysis of treated surfaces of five different commercial dental titanium implants</article-title>. <source>Mater Res</source><volume>15</volume>: <fpage>372</fpage>–<lpage>382</lpage>.</mixed-citation></ref><ref id="pone.0100624-Chrcanovic3"><label>33</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Leão</surname><given-names>NLC</given-names></name>, <name><surname>Martins</surname><given-names>MD</given-names></name> (<year>2013</year>) <article-title>Influence of different acid etchings on the superficial characteristics of Ti sandblasted with Al2O3</article-title>. <source>Mater Res</source><volume>16</volume>: <fpage>1006</fpage>–<lpage>1014</lpage>.</mixed-citation></ref><ref id="pone.0100624-Chrcanovic4"><label>34</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Martins</surname><given-names>MD</given-names></name> (<year>2014</year>) <article-title>Study of the influence of acid etching treatments on the superficial characteristics of Ti</article-title>. <source>Mater Res</source><volume>17</volume>: <fpage>373</fpage>–<lpage>380</lpage>.</mixed-citation></ref><ref id="pone.0100624-Wennerberg1"><label>35</label><mixed-citation publication-type="journal"><name><surname>Wennerberg</surname><given-names>A</given-names></name>, <name><surname>Albrektsson</surname><given-names>T</given-names></name> (<year>2010</year>) <article-title>On implant surfaces: a review of current knowledge and opinions</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>25</volume>: <fpage>63</fpage>–<lpage>74</lpage>.<pub-id pub-id-type="pmid">20209188</pub-id></mixed-citation></ref><ref id="pone.0100624-Chrcanovic5"><label>36</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Oliveira</surname><given-names>DR</given-names></name>, <name><surname>Custódio</surname><given-names>AL</given-names></name> (<year>2010</year>) <article-title>Accuracy evaluation of computed tomography-derived stereolithographic surgical guides in zygomatic implant placement in human cadavers</article-title>. <source>J Oral Implantol</source><volume>36</volume>: <fpage>345</fpage>–<lpage>355</lpage>.<pub-id pub-id-type="pmid">20545538</pub-id></mixed-citation></ref><ref id="pone.0100624-VandeVelde2"><label>37</label><mixed-citation publication-type="journal"><name><surname>Van de Velde</surname><given-names>T</given-names></name>, <name><surname>Glor</surname><given-names>F</given-names></name>, <name><surname>De Bruyn</surname><given-names>H</given-names></name> (<year>2008</year>) <article-title>A model study on flapless implant placement by clinicians with a different experience level in implant surgery</article-title>. <source>Clin Oral Implants Res</source><volume>19</volume>: <fpage>66</fpage>–<lpage>72</lpage>.<pub-id pub-id-type="pmid">17956565</pub-id></mixed-citation></ref><ref id="pone.0100624-Campelo1"><label>38</label><mixed-citation publication-type="journal"><name><surname>Campelo</surname><given-names>LD</given-names></name>, <name><surname>Camara</surname><given-names>JR</given-names></name> (<year>2002</year>) <article-title>Flapless implant surgery: a 10-year clinical retrospective analysis</article-title>. <source>Int J Oral Maxillofac Implants</source><volume>17</volume>: <fpage>271</fpage>–<lpage>276</lpage>.<pub-id pub-id-type="pmid">11958411</pub-id></mixed-citation></ref><ref id="pone.0100624-Chiapasco1"><label>39</label><mixed-citation publication-type="journal"><name><surname>Chiapasco</surname><given-names>M</given-names></name>, <name><surname>Zaniboni</surname><given-names>M</given-names></name> (<year>2009</year>) <article-title>Clinical outcomes of GBR procedures to correct peri-implant dehiscences and fenestrations: a systematic review</article-title>. <source>Clin Oral Implants Res</source><volume>20</volume> Suppl 4<fpage>113</fpage>–<lpage>23</lpage>.<pub-id pub-id-type="pmid">19663958</pub-id></mixed-citation></ref><ref id="pone.0100624-Annibali1"><label>40</label><mixed-citation publication-type="journal"><name><surname>Annibali</surname><given-names>S</given-names></name>, <name><surname>Ripari</surname><given-names>M</given-names></name>, <name><surname>La Monaca</surname><given-names>G</given-names></name>, <name><surname>Tonoli</surname><given-names>F</given-names></name>, <name><surname>Cristalli</surname><given-names>MP</given-names></name> (<year>2009</year>) <article-title>Local accidents in dental implant surgery: Prevention and treatment</article-title>. <source>Int J Periodontics Restorative Dent</source><volume>29</volume>: <fpage>325</fpage>–<lpage>331</lpage>.<pub-id pub-id-type="pmid">19537472</pub-id></mixed-citation></ref><ref id="pone.0100624-Wood1"><label>41</label><mixed-citation publication-type="journal"><name><surname>Wood</surname><given-names>DL</given-names></name>, <name><surname>Hoag</surname><given-names>PM</given-names></name>, <name><surname>Donnenfeld</surname><given-names>OW</given-names></name>, <name><surname>Rosenfeld</surname><given-names>LD</given-names></name> (<year>1972</year>) <article-title>Alveolar crest reduction following full and partial thickness flaps</article-title>. <source>J Periodontol</source><volume>42</volume>: <fpage>141</fpage>–<lpage>144</lpage>.<pub-id pub-id-type="pmid">4501971</pub-id></mixed-citation></ref><ref id="pone.0100624-Chrcanovic6"><label>42</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Abreu</surname><given-names>MH</given-names></name>, <name><surname>Freire-Maia</surname><given-names>B</given-names></name>, <name><surname>Souza</surname><given-names>LN</given-names></name> (<year>2010</year>) <article-title>Facial fractures in children and adolescents: a retrospective study of 3 years in a hospital in Belo Horizonte, Brazil</article-title>. <source>Dent Traumatol</source><volume>26</volume>: <fpage>262</fpage>–<lpage>270</lpage>.<pub-id pub-id-type="pmid">20456472</pub-id></mixed-citation></ref><ref id="pone.0100624-Chrcanovic7"><label>43</label><mixed-citation publication-type="journal"><name><surname>Chrcanovic</surname><given-names>BR</given-names></name>, <name><surname>Abreu</surname><given-names>MH</given-names></name>, <name><surname>Freire-Maia</surname><given-names>B</given-names></name>, <name><surname>Souza</surname><given-names>LN</given-names></name> (<year>2012</year>) <article-title>1,454 mandibular fractures: a 3-year study in a hospital in Belo Horizonte, Brazil</article-title>. <source>J Cranio-Maxillofac Surg</source><volume>40</volume>: <fpage>116</fpage>–<lpage>123</lpage>.</mixed-citation></ref></ref-list></back></pmc></record>Pour manipuler ce document sous Unix (Dilib)
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