Effects of bone morphogenetic protein-6 on periodontal wound healing/regeneration in supraalveolar periodontal defects in dogs

Objective Application of a synthetic BMP-6 polypeptide in a rat periodontal fenestration defect model enhanced periodontal wound healing/regeneration including new bone and cementum formation. The purpose of this study was to translate the relevance of these initial observations into a discriminating large animal model. Methods Critical-size (45mm) supraalveolar periodontal defects were created at the 2nd and 3rd mandibular premolar teeth in 11 Beagle dogs. Experimental sites received BMP-6 at 0.25, 1.0 and 2.0mg/ml soak-loaded onto an absorbable collagen sponge (ACS) carrier or ACS alone (control) each condition repeated in four jaw quadrants. The animals were euthanized at 8weeks when block biopsies were collected and processed for histologic/histometric analysis. Results BMP-6 at 0.25, 1.0 and 2.0mg/ml soak-loaded onto the ACS yielded significantly enhanced new bone (0.99 +/- 0.07 versus 0.23 +/- 0.13mm/BMP-6 at 0.25mg/ml) and cementum (2.45 +/- 0.54 versus 0.73 +/- 0.15mm/BMP-6 at 0.25mg/ml) formation including a functionally oriented periodontal ligament compared with control (p<0.05). A significant inverse linear association between BMP-6 dose and new bone (=0.21 +/- 0.09mm, p=0.016) and cementum height (=0.34 +/- 0.15mm, p=0.023) was observed. Minimal root resorption was observed without significant differences between groups. Ankylosis was not observed for any of the experimental groups. Conclusions Surgical application of BMP-6/ACS onto critical-size supraalveolar defects enhanced periodontal wound healing/regeneration, in particular cementogenesis including a functionally oriented periodontal ligament; the low BMP-6 0.25mg/ml concentration apparently providing the most effective dose.