PERIODONTAL REPAIR IN DOGS - EFFECT OF ALLOGENIC FREEZE-DRIED DEMINERALIZED BONE-MATRIX IMPLANTS ON ALVEOLAR BONE AND CEMENTUM REGENERATION

THE OBJECTIVE OF THIS STUDY was to evaluate alveolar bone and cementum regeneration following surgical placement of an allogenic, freeze-dri ed, demineralized bone matrix (DBM) cortical strip implant. Critical s ize, supraalveolar periodontal defects were surgically created around the second, third, and fourth mandibular premolar teeth in eight mongr el dogs. Contralateral jaw quadrants in six animals were randomly assi gned to receive the DBM implant, or serve as surgical control. Two add itional animals received bilateral DBM implants. Flaps were coronally advanced to submerge teeth and implants, and sutured. Three animals we re exited from the study due to extensive early wound failure. Remaini ng animals were sacrificed at 8 weeks postsurgery. Histometric recordi ngs included defect height, bone regeneration/DBM implant height, ceme ntum regeneration height, root resorption, and ankylosis. Large areas of unresorbed DBM exhibiting fragmentation and empty osteocyte lacunae were observed adjacent to new bone formation, or bone formation was o bserved adjacent to or within the implant, often exhibiting ankylosis. Cementum regeneration appeared enhanced in shelter of the DBM implant . Histometric recordings (mean+/-SD) for DBM and control defects, resp ectively, were: defect height, 4.8+/-0.2 mm and 4.4+/-0.2 mm; bone reg eneration/DBM implant height, 4.0+/-1.3 mm and 1.2+/-0.6 mm; cementum regeneration height, 1.4+/-0.4 mm and 0.7+/-0.2 mm; root resorption, 0 .5+/-0.3 mm and 1.2+/-0.3 mm; and ankylosis, 0.5+/-0.2 mm and 0.1+/-0. 1 mm without statistically significant differences between experimenta l conditions (N=3). Within the limitations of this study, the histolog ic observations suggest that surgical implantation of allogenic, freez e-dried DBM cortical strip implants may have a potential to support ce mentum regeneration, possibly by providing conditions for guided tissu e regeneration, however, alveolar regeneration appears unpredictable.