Cone beam computed tomography vs. microcomputed tomography for trabecular bone healing assessment : An ex vivo study in rabbit mandibles.

Purpose: This study aimed to compare cone beam computed tomography (CBCT) and microcomputed tomography (μCT) data to evaluate the micromorphological structure of healing bone in defects created on rabbit mandibles at different stages.

Methods: Residual rabbit mandibular alveolar bone tissues from another animal study involving 18 rabbits were utilized. In the prior study, 10 × 4 mm bone cavities were created, left to heal naturally, and the animals were sacrificed after 21, 45, and 90 days. In this study, CBCT and μCT imaging were performed on the excised defect regions. The micromorphometry parameters including bone-volume fraction (BV/TV), bone-surface density (BS/TV), fractal dimension, connectivity density (Conn. Dn.), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were examined by ImageJ (US National Institutes of Health, Bethesda, MD, USA). Paired two-sample t‑tests, Wilcoxon test, and Bland-Altman plots were performed.

Result: Differences in the parameters Conn. Dn., fractal dimension, Tb.Th, and Tb.Sp were observed between CBCT and μCT on day 21. By day 45, no significant differences were noted in BV/TV, BS/TS, Tb.Th, and Tb.Sp. On day 90, all measured parameters showed no statistically significant differences between CBCT and μCT. Bland-Altman analysis showed an agreement for most parameters (BV/TV, BS/TV, fractal dimension, Tb.Th, and Tb.Sp) after 21, 45, and 90 days, with minimal biases emerging over time, while a more notable divergence in Conn. Dn. was observed.

Conclusion: CBCT can be used for micromorphological analyses on days 45 and 90 of bone healing as there were no differences between CBCT and μCT during these periods.