Evidence-Based (2002) 3, 12±13 ã 2002 Evidence-Based Dentistry All rights reserved 1462-0049/02 $25.00 www.nature.com/ebd summary Results of guided tissue regeneration are highly variable Needleman IG, Giedrys-Leeper E, Tucker RJ, Worthington HV. Guided tissue regeneration for periodontal infra-bony defects (Cochrane Review). In: The Cochrane Library, Issue 2, 2001. Oxford: Update Software

Objective To assess the efficacy of guided tissue regeneration Table 1 Summary of meta-analysis (GTR) in the treatment of periodontal infra-bony defects measured Weighted mean difference against the current standard of surgical periodontal treatment, open- (mm) (95% CI) flap . Hard tissue Data sources The Cochrane Oral Health Group specialised trials Attachment Probing probing at register, Medline, hand searches of the Journal of , level depth surgical Clinical Periodontology, Periodontal Research and bibliographies of all change reduction re-entry relevant papers and review articles, up to October 2000. In addition, GTR alone and 1.11 0.80 1.39 experts, groups and companies involved in surgical research were open-flap debridement (0.63±1.59) (0.14±1.46) (1.08±1.71) contacted to find other trials or unpublished material or to clarify GTR plus bone substitutes 1.25 1.24 3.37 ambiguous or missing data. Requests for data were also posted on two and open-flap debridement (0.89±1.61) (0.89±1.59) (3.14±3.61) periodontal electronic discussion groups. Study selection Randomised controlled trials (RCT) of at least 12 months' duration comparing GTR (with or without graft materials) open-flap debridement was eight (95% CI, 4±33), based on an incidence with open-flap debridement for the treatment of periodontal infra- of 32% of sites in the control group failing to gain 2 mm or more of bony defects. Furcation involvement and studies specifically treating attachment. For baseline incidences in the range of the control groups early onset diseases were excluded. of 10% and 55% the NNTs are 24 and 3. Data extraction and synthesis Initial screening of studies was Conclusions Overall, GTR was a little more effective in increasing conducted independently by two reviewers and data abstraction by attachment gain, reducing pocket depth and favouring gain in hard three reviewers, with methodological quality assessed using both tissue probing at re-entry surgery. The marked variability between individual components and the Jadad scale. Inter-rater agreement was studies limits conclusions about the clinical benefit of GTR, however. determined by Kappa scores. Methodological quality was used in There is evidence that GTR can produce a significant improvement over sensitivity analyses to test the robustness of the conclusions. The results conventional open-flap surgery but the factors responsible for success were expressed as weighted mean differences (WMD) and 95% or failure are not clear from the literature. We recommend that future confidence intervals (CI) for continuous outcomes and as relative risk trials should follow the CONSORT guidelines both in their conduct and (RR) and 95% CI for dichotomous outcomes, calculated using reporting. Studies should aim to identify factors associated with random-effects models where significant heterogeneity was detected achieving consistent benefits over open-flap surgery and these benefits (P50.1). The primary outcome measure was gain in clinical should include traditional probing outcomes as well as considering attachment. patient-centred endpoints. Open-flap surgery should remain the control comparison in these studies Results Eleven studies were finally included in the review, 10 testing GTR alone and two testing GTR plus bone substitutes (one study had Evidence-Based Dentistry (2002) 3, 12±13. DOI: 10.1038/sj/ both test treatment arms). Statistically significant differences were ebd/6400083 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 Address for reprints: Dr Ian Needleman, Lecturer, Department of as poor using the Jadad score. The number needed to treat (NNT) for Periodontology, Eastman Dental Institute, 256 Gray's Inn Road, London GTR to achieve one extra site gaining 2 mm or more attachment over WC1X 8LD, UK. E-mail: [email protected]

Commentary therapy involves flap surgery, debridement of During GTR therapy a partially occlusive is the most common the affected area and, often, osseous recon- is placed between the form of , affecting up to touring. Although periodontal pocket depths healing flap and the root/ bone surface. The 30% of the adult population.1 The ultimate are decreased, the results may be less than ideal principle behind the use of this membrane is goal of periodontal therapy has been regen- from the patient's point of view, as there may to exclude the rapidly proliferating epithelial eration of tissues lost due to disease, but this be an increase in dentinal hypersensitivity and cells from migrating down the healing wound goal remains elusive. Traditional surgical a negative change in aesthetics. surface. Theoretically, this allows the slower 13 moving periodontal ligament cells and osteo- with a traditional , these factors) such as plaque levels, cigarette smok- genic cells to migrate into the wound, differences do not appear to be clinically ing and baseline severity of the defect. Another regenerating lost tissue. In addition to un- significant. The addition of bone substitutes is that this is a technically sensitive procedure known efficacy, the drawbacks of GTR therapy did not significantly alter the results. Although and thus highly surgeon-dependent. Noting are increased expense and, in the case of a non- the difference in hard tissue probing is higher, that two of the studies showed twice the resorbable membrane, a second surgical it does not seem to impact on attachment level attachment-level gain of the overall group procedure. changes. estimate, this hypothesis seems to have some This systematic review synthesises the litera- A more meaningful outcome than pocket merit. ture on the use of GTR in the treatment of depth or attachment level change would be the As with many clinical trials in dentistry, none infra-bony defects (ie, bony craters). Much number of sites gaining at least 2 mm of of these investigations reported patient-based has been written over the last 25 years in this attachment. This threshold is one that is more outcomes. The likelihood of post-operative area. Needleman et al. found 11 randomised likely to alter management decisions on the complications, changes in aesthetics or future controlled trials that met their review's inclu- part of the clinician. From the analysis in this tooth loss can play a significant role in how sion criteria. Unfortunately, the quality of review it was determined that eight sites would patients choose between alternative therapies. most of these studies was poor: many need to be treated with GTR for one site to Thus, in addition to identifying factors publications presented incomplete methods show 2 mm attachment gain (ie, NNT). It is associated with successful outcomes of GTR or results, and outcomes measured were rare that only one site per tooth is affected by therapy, some consideration should be given highly variable between studies. Of the 10 an infra-bony defect. Yet even if an average of to measuring quality-of-life outcomes in studies dealing with GTR alone (ie, no bone four sites per tooth were affected, and two future trials. substitutes) versus traditional flap surgery, teeth were treated with GTR in a particular From the details of this rigorous, well- seven received a quality score of less than 3 patient, results from this review suggest only documented review it is clear that any positive (out of a possible 4) Ð poor quality reports. one site on those two teeth would show reported results must be viewed with caution. Of the remaining four studies, one scored 3, significant clinical improvement. For those It appears that a method that can consistently and the others, 4. It bears repeating that all who are risk-averse, these do not seem like regenerate periodontal tissue lost because of future clinical researchers (not just those in favourable odds. For others, it might be worth disease eludes us still. periodontal regenerative research) should the gamble (and the additional costs), espe- follow the CONSORT guidelines in both the cially in areas of aesthetic concern. 1. Oliver R, Brown L, Loe H. Variations in the conduct of trials and the reporting of results. This review found the results between prevalence and extent of periodontitis. J Meta-analysis revealed that the weighted studies or centres were highly variable. In the Am Dent Assoc 1991; 122:43±48. mean difference in probing depth and attach- 10 studies examining GTR alone, the changes ment level between GTR and traditional in clinical attachment ranged from 0.02± surgery was 0.80 and 1.11 mm, respectively. 2.60 mm. Analysis performed with and with- If we presume that the average changes in out results of the poorer quality studies could Debora C Matthews probing depth and attachment level were not explain the heterogeneity. There are many Division of Periodontics, calculated using just the sites treated and not possible explanations for this. Part of the Faculty of Dentistry, the entire mouth or sextant, and accounting difference may be due to differences in Dalhousie University, Halifax, for potential measurement error of 1±2 mm accounting for confounders (or prognostic Nova Scotia, Canada

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