The Effect of Xenografts Used In Combination With or Without Bioresorbable Membranes in the Treatment of Experimental Ridge Dehiscene Defects Following Extractions in Dogs
The purpose of this study was to evaluate the regenerative outcome of bone tissue that occurs in canine alveolar ridge defects following placement of deproteinized porous bovine bone mineral (Bio-Oss® , Osteohealth) alone or in combination with a collagen bilayer membrane (Bio-Gide® , Osteohealth) using the principle of guided bone regeneration (GBR).
Materials & Methods
The mandibular premolars (P2, P3 and P4) were extracted unilaterally in three mongrel dogs, and the remaining alveolar bone was surgically reduced in width and height to produce three alveolar ridge defects. Subsequently, the ridge dehiscence defect sites in each dog were treated with one of the following three modalities: one site received Bio-Oss alone ("BO group"); one site received Bio-Gide membrane supported by Bio-Oss ("BO+BG group"); one site received neither membrane nor bone graft and served as control ("C group").
All sites healed well without signs of infection. Second surgical reentry at 4 months showed defected extraction sockets completely filled by bone-like tissue in both experimental groups. Bone level changes were evaluated radiographically in addition to analyzing computed tomography images. At 16 and 20 weeks following ridge augmentation, increased radiopaque signs indicative of bone regeneration were observed in all ridge dehiscence defects using regenerative procedure, whereas in untreated control group radiographic appearance showed poor osseous fill. The changes of alveolar bone density using optical densitometry demonstrated that there is significant difference (P< 0.05) between the mean density change between sites treated with and without membranes by the Fisher' LSD method. In gross evaluation of the 3D-CT reconstruction of the canine mandibles after 5 months of implantation, areas implanted with Bio-Oss combination Bio-Gide exhibited the greatest amount of bone augmentation and excellent thickness of the buccal aspect of the alveolar ridge.
These results suggest that anorganic porous bovine bone mineral tested enhances more successful bone regeneration for GBR procedure, in particular in conjunction with the use of a porcine derived collagen membrane as a barrier in promoting regeneration of canine alveolar ridge defects.