Localized ridge augmentation in dogs: a pilot study using membranes and hydroxyapatite.

This study was designed to evaluate the potential to reconstruct localized ridge defects with bone by preventing non-osteogenic extraskelatal connective tissue from participating in the process of healing following experimental ridge augmentation treatment procedures. Following the elevation of buccal muco-periosteal flaps, buccal, interproximal, and interradicular bone was removed to the apical level of the second and third premolar teeth and the teeth were extracted to create bucco-lingual ridge defects that averaged 13 mm x 7 mm x 3.5 mm in each quadrant of two adult beagle dogs. The defects were permitted to heal for 90 days. The defects did not fill in with new bone. Subsequently, buccal muco-periosteal flaps were elevated and a membrane was placed over the defect and positioned so that it rested on bone that was exposed adjacent to the defect. In two quadrants test support materials were used to ensure that a space was maintained between the surface of the defect and the membrane. One quadrant was maintained as a sham-operated control site, three sites received membranes and no supporting implants and two sites received supporting implants and no membranes. The surgical schedule was designed to yield sacrifice times of 8 to 12 weeks. In the three quadrants available for study that were covered with membranes, bone and/or non-mineralized connective tissue was found to fill all of the space that had been provided by the membrane. Histologic examination confirmed that the space was filled with young, actively growing bone by 90 days. No new bone formation (bone fill) was observed in the sham-operated control site.