Guided tissue regeneration with a bioabsorbable polylactic acid membrane in gingival recessions. A histometric study in dogs

Background: The goal of this investigation was to histologically and histom etrically evaluate the healing process of gingival recessions treated by gu ided tissue regeneration with bioabsorbable polylactic acid membranes (GTR group) and to compare it to that obtained with coronally positioned flaps ( CPF group). Methods: Gingival recessions were surgically created on the buccal aspect o f the upper cuspids of 5 mongrel dogs. The defects (5x7 mm) were exposed to plaque accumulation for 3 months. The contralateral defects were then rand omly assigned to each group. After 3 months of healing, the dogs were sacri ficed and the blocks were processed. The histometric parameters evaluated i ncluded length of sulcular and junctional epithelium, connective tissue ada ptation, new cementum, new bone, and defect coverage. Results: The extension of the epithelium was 1.9 +/- 0.8 mm for the GTR-gro up and 3.0 +/- 0.9 mm for the CPF-group (P = 0.16). The connective tissue a daptation was 0.1 +/- 0.1 and 0.8 +/- 0.5 mm in the GTR group and CPF group , respectively (P = 0.051). The new cementum was 3.8 +/- 1.5 mm and 2.4 +/- 0.3 mm in the GTR group and CPF group, respectively (P = 0.16). Bone forma tion was 1.1 +/- 0.5 mm in the GTR group and 1.4 +/- 0.2 mm in the CPF grou p (P = 0.53). Histologically, the defect coverage observed was similar, 90. 5% and 91.9% for the GTR group and the CPF group, respectively. No statisti cal differences in any of the parameters could be detected. Conclusions: Within the limits of this study, it can be concluded that both procedures resulted in a favorable healing response with no significant di fference between the treatments.