Evaluation of new high-performance calcium polyphosphate bioceramics as bone graft materials

The purpose of this study was to evaluate the ability of a recently developed porous calcium polyphosphate bioceramic (CPB) to function as a bone graft substitute. After six weeks, postsurgical extraction of the mandibular first and second molars, alveolar ostectomies were performed bilaterally in five dogs. The ridge forms were then restored using the CPB implant material on one side and the autogenous bone obtained from the contralateral ostectomy site on the other. The graft and implant sites were retrieved after 4 months and decalcified and undecalcified sections were prepared for special staining (modified Attwood) and subsequent light microscopy and histomorphometry. In addition, the undecalcified sections were prepared for histometry using backscattered electron imaging (BSEI). Histologically, the CPB implants showed extensive vascularization and cellularity within an "invading" loose connective tissue matrix. On the opposite side, the loose connective tissue of the autografts showed hypovascularity and hypocellularity. Neither the implants nor the autografts showed any histologic evidence of an inflammatory reaction. Using light microscopic histomorphometry, the implants showed a higher incidence of union than the autografts. On BSEI histometry, the CPB implants showed significantly greater new bone formation than the autografts. This study reveals that porous CPB possesses certain characteristics essential for the "ideal" implantable bone substitute necessary for the repair of craniofacial and other bony defects.