title: Guided tissue regeneration-based root coverage: meta-analysis.
abstract: BACKGROUND
  The goal of guided tissue regeneration-based root coverage (GTRC) is to repair gingival recession via new attachment formation. Numerous clinical trials have been conducted utilizing the concept of GTR to promote root coverage. Most GTRC studies have had relatively small sample sizes and have not utilized power calculations to determine appropriate sample size; therefore, it is difficult to draw strong conclusions from them. Hence, the purpose of this study is to combine data from currently available GTRC studies and to use meta-analysis to determine whether GTRC provides significantly improved clinical outcomes compared to conventional periodontal plastic surgical approaches for the treatment of marginal tissue recession.
  
  
  METHODS
  Studies were identified that used GTR approaches to treat gingival recession from January 1990 to October 2001. Information from each study was entered into a database. Data were analyzed according to the following criteria: GTRC versus conventional mucogingival surgery (CMGS); membrane type; root conditioning; pretreatment recession depth; adjunctive use of bone replacement graft (BRG); and source of funding. Studies were ranked independently, and mean data from each were weighted accordingly. Meta-analysis was performed using the weighted means for each group. Paired t tests were used to determine statistical significance between each pair of groups.
  
  
  RESULTS
  Forty papers were included for analysis. GTRC resulted in an average of 74% recession depth reduction, 41% complete root coverage, 3 mm AL gain, and 1 mm KG gain. Both GTRC and CMGS produced significant (P < 0.05) improvement compared to baseline measurements. Compared to GTRC, CMGS resulted in significantly (P < 0.05) increased KG (2.1 mm vs. 1.1 mm), root coverage (81% vs. 74%), and percentage of defects with complete root coverage (55% vs. 41 %). Use of absorbable membranes, root conditioning, shallow pretreatment recession (< 4 mm), and corporate sponsorship all resulted in significantly (P < 0.05) improved percentages of sites with complete root coverage but had no effect on other parameters.
  
  
  CONCLUSIONS
  Based on this meta-analysis, guided tissue regeneration-based root coverage can be used successfully to repair gingival recession defects. Conventional mucogingival surgery, however, resulted in statistically better root coverage, width of keratinized gingiva, and complete root coverage.
authors.affiliation: Department of Periodontics/Prevention/Geriatrics, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Khalid
authors.initials: K
authors.lastname: Al-Hamdan
authors.forename: Robert
authors.initials: R
authors.lastname: Eber
authors.forename: David
authors.initials: D
authors.lastname: Sarment
authors.forename: Charles
authors.initials: C
authors.lastname: Kowalski
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D020341:Absorbable Implants; D016025:Bone Transplantation; D005889:Gingival Recession / Q000601:surgery*; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D008567:Membranes, Artificial
chemical_list: D008567:Membranes, Artificial