We used the combination of a thermoplastic bioresorbable plate and a beta-tricalcium phosphate (β -TCP) grafting substitute for bone defects to induce three-dimensional bone regeneration and evaluated the regenerated bone by histological, ultrastructual, and elemental mapping analyses. Standardized bone defects surgically formed in rat calvariae were filled with β -TCP particles (OSferion
®) and covered with a domeshaped plate (LactoSorb
®). In the control group, bone defects were covered with a plate without grafting β -TCP particles. In the experimental group, newly formed woven bone extended from the bottom of the defects at 2 weeks. Osteopontin immunopositivity was seen throughout the β -TCP particles grafted in the bone cavity. At the bottom of the cavity, alkaline phosphatase (ALP)-positive cells and tartrate-resistant acid phosphatase (TRAP)-positive cells were localized on the β -TCP particles. At 4 weeks, the new bone had reached half of the height of the cavity, and at 8 weeks, it was close to the plate. At 24 weeks, the new bone had reached the height of the plate and showed histological characteristics of compact bone. The volume of β -TCP particles had decreased and was replaced by new bone. Analyses using a transmission electron microscope and electron probe microanalyzer also revealed that the new bone showed the properties of compact bone. In the control group, the new bone encapsulated with fibrous tissue did not have sufficient height to reach the dome-shaped plate. The results indicate that new bone established by the combination of a thermoplastic bioresorbable plate and a β -TCP grafting substitute might be an alternative material for mandible reconstruction.
View full abstract