Investigation of periodontal tissue regeneration using octacalcium phosphate and collagen composite

This study aimed to investigate periodontal tissue regenerative potential of octacalcium phosphate (OCP) and collagen composite (OCPcol), recognized as excellent bone-regenerative materials, in artificial bone defect models using beagle dogs. This study specifically assessed the efficacy of OCPcol in periodontal soft-tissue regeneration. OCPcol was implanted in bone defects adjacent to the roots of the left mandibular third and fourth premolars in six beagle dogs (OCP group), while five dogs did not receive OCPcol (control group). The dogs were observed for 3 months. The specimens were evaluated radiologically and histologically. Microcomputed tomography revealed bone regeneration originating from the lateral cortical bone surface adjacent to the created defect. The superficial layer of the regenerated bone was cortical bone-like and continuous with the upper and lower alveolar bone. The bone was regenerated by maintaining a continuous void in the periodontal ligament space above and below the dentinal defect. Dental defects of roots were not regenerated. The control group did not exhibit sufficient bone regeneration. Histologically, in the OCP group, formation of new cementum was observed on the outer surface of the root dentin, with connective tissue attachment and an oblique-running periodontal ligament in the space between the new bone and dentin. However, the dentinal defects were not regenerated． Alveolar bone and periodontal ligament regenerated when OCPcol was implanted into a bone and dentinal defect created around a natural tooth root. These results suggest that OCPcol effectively regenerates periodontal tissue, without ankylosis.