Healing at mandibular block-grafted sites. An experimental study in dogs

AIM The aim of this study was to evaluate the healing of autologous bone block grafts or deproteinized bovine bone mineral (DBBM) block grafts applied concomitantly with collagen membranes for horizontal alveolar ridge augmentation. MATERIAL AND METHODS In six Labrador dogs, molars were extracted bilaterally, the buccal bony wall was removed, and a buccal box-shaped defect created. After 3 months, a bony block graft was harvested from the right ascending ramus of the mandible and reduced to a standardized size. A DBBM block was tailored to similar dimensions. The two blocks were secured with screws onto the buccal wall of the defects in the right and left sides of the mandible, respectively. Resorbable membranes were applied at both sides, and the flaps sutured. After 3 months, one implant was installed in each side of the mandible, in the interface between grafts and parent bone. After 3 months, biopsies were harvested and ground sections prepared to reveal a 6-month healing period of the grafts. RESULTS 77 ± 6.2% and 5.9 ± 7.5% of vital mineralized bone were found at the autologous bone and DBBM block graft sites, respectively. Moreover, at the DBBM site, 63 ± 11.7% of connective tissue and 31 ± 15.5% of DBBM occupied the area analyzed. Only 0.2 ± 0.4% of DBBM was found in contact with newly formed bone. The horizontal loss was in a mean range of 0.9-1.8 mm, and 0.3-0.8 mm, at the autologous bone and DBBM block graft sites, respectively. CONCLUSIONS Autologous bone grafts were vital and integrated to the parent bone after 6 months of healing. In contrast, DBBM grafts were embedded into connective tissue, and only a limited amount of bone was found inside the scaffold of the biomaterial