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-dried, demineralized bone matrix (DBM) cortical strip implant. Critical size, supraalveolar periodontal defects were surgically created around the second, third, and fourth mandibular premolar teeth in eight mongrel dogs. Contralateral jaw quadrants in six animals were randomly assigned to receive the DBM implant, or serve as surgical control. Two additional animals received bilateral DBM implants. Flaps were coronally advanced to submerge teeth and implants, and sutured. Three animals were exited from the study due to extensive early wound failure. Remaining animals were sacrificed at 8 weeks post-surgery. Histometric recordings included defect height, bone regeneration/DBM implant height, cementum 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 observed 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, respectively, were: defect height, 4.8 ± 0.2 mm and 4.4 ± 0.2 mm; bone regeneration/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 experimental conditions (N=3). Within the limitations of this study, the histologic observations suggest that surgical implantation of allogenic, freeze-dried DBM cortical strip implants may have a potential to support cementum regeneration, possibly by providing conditions for guided tissue regeneration, however, alveolar regeneration appears unpredictable.