Histological and histomorphometrical comparative study of β-tricalcium phosphate block grafts and periosteal expansion osteogenesis for alveolar bone augmentation

This study evaluated local tissue reaction around the beta-tricalcium phosphate (beta-TCP) block and compared results with beta-TCP block grafting and periosteal expansion osteogenesis (PEO). The mandibular premolars were extracted from five dogs and buccal corticotomy was performed. Narrow alveolar ridge models were created at 4 weeks. The beta-TCP block graft, such as veneer graft, was used on the right side and PEO using beta-TCP block on the left side. Changes of alveolar width, histological findings and histomorphometrical analysis were evaluated. There were no problems with materials at any of the sites at any time. In both groups, the width increased after surgery and results were stable 8 weeks after surgery. Newly formed bone tissue was observed inside the beta-TCP block in both sides. Histological findings differed especially at the division between mandibular bone and beta-TCP block. Histomorphometric analyses revealed that beta-TCP had been absorbed (mean decrease 28%) and new bone had formed (mean increase 43%) at 8 weeks postoperatively on both sides. The beta-TCP block worked as a space-maker under the soft tissue, including the periosteum, and acted as a substitute for original bone. This bone substitute was effective material for bone augmentation in both methods.