Evaluation of bone regeneration in a critical size cortical bone defect in rat mandible using microCT and histological analysis.

GOAL:Evaluate bone regeneration in a critical size bone defect model in the jaw of healthy rats as a function of gender and defect location. DESIGN:A series of microCT and histological studies were performed to evaluate the process of bone regeneration in rats with a mandibular critical size defect. Rats were placed in two groups according to gender and sorted in terms of bone defect location. Bone regeneration rate and hydroxyapatite concentration were assessed with microCT imaging at specific times after surgery. Histological analysis was also performed to evaluate bone regeneration. RESULTS:No more that 85% of bone regeneration was observed after 60 days, with a low rate constant (K) indicating a slow restoration of the defect. Assessment of microCT images showed partial closure of the defect in all cases, which was confirmed by histological analysis. Hydroxyapatite concentration values revealed that regenerated bone was not fully calcified. No statistically significant differences in terms of gender or defect location were found. CONCLUSION:The defect model studied here, located in the jaw of healthy rats, shows potential as a preclinical critical size bone defect model to evaluate bone regeneration therapies in the fields of dentistry and maxillofacial surgery.