GTR has a greater effect on probing measures of periodontal treatment than open flap debridement, including improved attachment gain, reduced pocket depth, less increase in gingival recession and more gain in hard tissue probing at re-entry surgery. However there is marked variability between studies and the clinical relevance of these changes is unknown. As a result, it is difficult to draw general conclusions about the clinical benefit of GTR. Whilst there is evidence that GTR can demonstrate a significant improvement over conventional open flap surgery, the factors affecting outcomes are unclear from the literature and these might include study conduct issues such as bias. Therefore, patients and health professionals need to consider the predictability of the technique compared with other methods of treatment before making final decisions on use. Since trial reports were often incomplete, we recommend that future trials should follow the CONSORT statement both in their conduct and reporting. 
There is therefore little value in future research repeating simple, small efficacy studies. The priority should be to identify factors associated with improved outcomes as well as investigating outcomes relevant to patients. Types of research might include large observational studies to generate hypotheses for testing in clinical trials, qualitative studies on patient-centred outcomes and trials exploring innovative analytic methods such as multilevel modelling. Open flap surgery should remain the control comparison in these studies.
Periodontal regeneration of human intrabony defects with titanium reinforced membranes. A controlled clinical trial.
The purpose of this controlled clinical trial was to compare the clinical efficacy of 3 treatment modalities in the treatment of deep interproximal intrabony defects. Forty-five (45) defects in 45 patients were randomly assigned to 1 of 3 treatment groups by blocking to prognostic variables. The test group was treated with titanium reinforced membranes positioned just apical to the cemento-enamel junction and the modified papilla preservation technique; the second group received conventional expanded polytetrafluoroethylene (ePTFE) barrier membranes applied at the alveolar crest; the third group was treated with an access flap procedure. The groups were well balanced with respect to all prognostic variables. During the 1-year observation period, patients were subjected to a stringent infection control program including: professional tooth cleaning every week for the first 6 weeks (all groups) and in the 4 weeks following membrane removal (guided tissue regeneration groups), then at monthly intervals (all groups). The results indicated that: 1) all treatment modalities resulted in clinical and statistically significant improvements in clinical attachment level (CAL) and probing depths (PD) at 1 year; 2) a significantly greater amount of CAL gain (P = 0.0003, analysis of variance) was observed in the test group (5.3 +/- 2.2 mm) with respect to both the ePTFE group (4.1 +/- 1.8 mm) and the flap control group 2.5 +/- 0.8; 3) in the test group the 1 year CAL (4.7 +/- 1.8 mm) was located more coronally than the baseline position of the interproximal alveolar crest (5.9 +/- 2 mm; P = 0.003, t test).(ABSTRACT TRUNCATED AT 250 WORDS)