Results of guided tissue regeneration are highly variable

Abstract

Objective: To assess the efficacy of guided tissue regeneration (GTR) in the treatment of periodontal infra-bony defects measured against the current standard of surgical periodontal treatment, open-flap debridement.Data sources: The Cochrane Oral Health Group specialised trials register, Medline, hand searches of the Journal of Periodontology, Clinical Periodontology, Periodontal Research and bibliographies of all relevant papers and review articles, up to October 2000. In addition, experts, groups and companies involved in surgical research were contacted to find other trials or unpublished material or to clarify ambiguous or missing data. Requests for data were also posted on two periodontal electronic discussion groups.Study selection: Randomised controlled trials (RCT) of at least 12 months' duration comparing GTR (with or without graft materials) with open-flap debridement for the treatment of periodontal infra-bony defects. Furcation involvement and studies specifically treating early onset diseases were excluded.Data extraction and synthesis: Initial screening of studies was conducted independently by two reviewers and data abstraction by three reviewers, with methodological quality assessed using both individual components and the Jadad scale. Inter-rater agreement was determined by Kappa scores. Methodological quality was used in sensitivity analyses to test the robustness of the conclusions. The results were expressed as weighted mean differences (WMD) and 95% confidence intervals (CI) for continuous outcomes and as relative risk (RR) and 95% CI for dichotomous outcomes, calculated using random-effects models where significant heterogeneity was detected (P<0.1). The primary outcome measure was gain in clinical attachment.Results: Eleven studies were finally included in the review, 10 testing GTR alone and two testing GTR plus bone substitutes (one study had both test treatment arms). Statistically significant differences were found for attachment level change, probing depth reduction and hard tissue probing at surgical re-entry (see Table 1). Heterogeneity between studies was highly statistically significant for all principal comparisons and could not be explained satisfactorily by sensitivity analyses. The quality of study-reporting was low, with seven out of 11 studies graded as poor using the Jadad score. The number needed to treat (NNT) for GTR to achieve one extra site gaining 2 mm or more attachment over open-flap debridement was eight (95% CI, 4–33), based on an incidence of 32% of sites in the control group failing to gain 2 mm or more of attachment. For baseline incidences in the range of the control groups of 10% and 55% the NNTs are 24 and 3.Conclusions: Overall, GTR was a little more effective in increasing attachment gain, reducing pocket depth and favouring gain in hard tissue probing at re-entry surgery. The marked variability between studies limits conclusions about the clinical benefit of GTR, however. There is evidence that GTR can produce a significant improvement over conventional open-flap surgery but the factors responsible for success or failure are not clear from the literature. We recommend that future trials should follow the CONSORT guidelines both in their conduct and reporting. Studies should aim to identify factors associated with achieving consistent benefits over open-flap surgery and these benefits should include traditional probing outcomes as well as considering patient-centred endpoints. Open-flap surgery should remain the control comparison in these studies