Influence of residual bone on recombinant human bone morphogenetic protein-2-induced periodontal regeneration in experimental periodontitis in dogs.

Background: Previous studies reported that bone morphogenetic protein (BMP)-2 induced periodontal regeneration in animals. However, the effects of local host factors on bone formation when using recombinant human (rh)BMP-2 are unknown. The purpose of this study was to evaluate local conditions in recipient sites that affected periodontal regeneration following BMP implantation in experimentally induced horizontal defects in dogs.

Methods: Experimental periodontitis was induced in the maxillary and mandibular premolars of six male beagles. The recipient sites were divided into four quadrants (maxillary buccal, maxillary palatal, mandibular buccal, and mandibular lingual sites). A polymer-coated gelatin sponge (PGS; 3 x 3 x 2 mm) was impregnated with 7.2 mul rhBMP-2 solution. The recipient sites in each quadrant were treated with physiologic saline/PGS and rhBMP-2/PGS (rhBMP-2 at 7.2 mug/7.2 mul). The dogs were sacrificed 12 weeks post-surgery, and healing was evaluated histologically.

Results: Bone formation and connective tissue attachment were observed following rhBMP-2/PGS implantation. In the four recipient sites of the BMP-treated group, significant positive correlations were found between the width of residual bone and the height and area of regenerated bone (r = 0.791; r = 0.828; P <0.0001). The height of regenerated bone was also significantly correlated to the area (r = 0.891; P <0.0001).

Conclusions: The width of residual bone was one of the clinical host factors that affected bone regeneration following BMP implantation. However, it did not affect connective tissue attachment, cementum regeneration, and downgrowth of junctional epithelium.