Histological Evaluation of Retrieved ePTFE Membranes After GTR

Objective: To evaluate the clinical outcomes following regenerative surgery with two different bone substitutes and GTR and to histologically analyse the newly formed tissues under the retrieved membranes. Methods: 35 patients each of whom exhibited one deep intrabony defect were randomly treated with either a natural bone mineral (NBM) + GTR or with a beta-tricalciumphosphate (beta-TCP) + GTR. Probing pocket depth (PPD) and clinical attachment level (CAL) were recorded at baseline and at 12 months. At 6 weeks following surgery, the ePTFE membranes were removed and subjected to histological analysis for: integration of the membrane into the regenerated tissues, hard tissue ingrowth and inflammatory cell components on the surfaces. Results: No statistical significant differences in any of the investigated clinical parameters were observed at baseline between the two groups. In the NBM + GTR group mean PPD decreased from 8.9 ± 2.0 mm to 2.3 ± 1.2 mm (p<0.001) and mean CAL changed from 9.7 ± 2.2 mm to 4.5 ± 2.0 mm (p<0.001). In the beta-TCP + GTR group mean PPD decreased from 8.3 ± 2.0 mm to 3.4 ± 2.0 mm (p<0.001) and mean CAL changed from 9.1 ± 2.2 mm to 4.5 ± 2.3 mm (p<0.001). At 12 months there were statistically significant differences in PPD change and not significant differences in CAL gain between the two groups. The histological analysis demonstrated statistically significantly higher osteoid formation and new bone ingrowth into the membranes treated with NBM + GTR (p<0.001) compared to those treated with beta-TCP + GTR. Conclusion: The present data indicate that: a) both treatments resulted in significant PPD reductions and CAL gains and b) treatment with NBM + GTR appeared to result in higher rates of osteoid formation compared to treatment with beta-TCP + GTR.