Implant placement for periosteal expansion osteogenesis using β-tricalcium phosphate block: An experimental study in dogs

Objectives: This study was performed to evaluate the clinical outcome of periosteal expansion osteogenesis for correction of a horizontally deficient alveolar ridge, stability of dental implants placed in the expanded areas, and osteocompatibility of β-tricalcium phosphate (β-TCP) block areas. Study design: The mandibular premolars were extracted and buccal corticotomy was performed in 5 female dogs. Narrow alveolar ridge models were produced at 10 weeks. The β-TCP block was placed at the lateral surface of the mandibular bone and 2 titanium screws were inserted from the lingual aspect to push the block to the buccal side. After a latency period of 8 days, during which time primary wound healing occurred, the lingual screws were advanced by approximately 0.5 mm/day for 6 days. The expansion areas were left untreated for 8 weeks. Then implants (diameter 3.5 mm, length 9 mm) were inserted into the gap between the β-TCP block and the original alveolar bone. We evaluated the changes in alveolar width, resonance frequency analysis of implants, and histomorphometric analysis of the β-TCP block. Results: No problems with the materials were observed at any of the sites of intervention before, during, or at the end of the experimental period. The width increased after expansion and showed stable results on week 8 from the end of expansion. Implants were placed in the expansion area and showed sufficient stability with slight increases in the implant stability quotient value until 8 weeks after implant placement. The amount of remaining β-TCP decreased significantly compared with the original amount of material inserted. The mean values remaining inside the block were 44.6 ± 8.2% and 32.1 ± 12.0% at 8 and 16 weeks of consolidation, respectively, whereas newly formed bone comprised 20.2 ± 7.2% and 33.5 ± 9.5%, respectively. Conclusions: Newly formed bone could be acquired by periosteal expansion osteogenesis using a β-TCP block for implant placement in a dog model. However, the bone volume was not stable after implant placement despite sufficient implant stability for 8 weeks.