title: The effect of flapless surgery on implant survival and marginal bone level: a systematic review and meta-analysis.
abstract: BACKGROUND
  The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach.
  
  
  METHODS
  An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included.
  
  
  RESULTS
  Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies.
  
  
  CONCLUSIONS
  This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.
authors.affiliation: Graduate Periodontics, Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI.
authors.forename: Guo-Hao
authors.initials: GH
authors.lastname: Lin
authors.forename: Hsun-Liang
authors.initials: HL
authors.lastname: Chan
authors.forename: Jill D
authors.initials: JD
authors.lastname: Bashutski
authors.forename: Tae-Ju
authors.initials: TJ
authors.lastname: Oh
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D016301:Alveolar Bone Loss / Q000145:classification; D000539:Alveolar Process / Q000473:pathology*; D015982:Bias; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D006801:Humans; D012107:Research Design; D013524:Surgical Flaps / Q000601:surgery; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants