Three-dimensional radiographic and histological tracking of rat mandibular defect repair after inferior alveolar nerve axotomy.

To sequentially track mandibular defect repair by using radiographic and histological techniques, so as to compare repair patterns of sensory denervated versus innervated mandibles. Forty Sprague-Dawley rats were subjected to unilateral inferior alveolar nerve (IAN) axotomy and bilateral 3 mm full-thickness circular osteotomy of their mandibles. Micro-CT and histological staining were applied to track the repair process of the mandibular defects at 1, 2, 4, and 8 weeks after surgery. The bone volume of both sides increased by 2 weeks post-operation, and then gradually decreased. The new bone volumes of the axotomy side were significantly less than that of the sham side at 1, 2, and 4 weeks post-surgery, whereas no significant differences were detected at 8 weeks post-surgery. Meanwhile, there were no significant differences in bone mineral density between the two sides during repair. Noteworthy, the repaired bone remained more vertically than horizontally aligned throughout the repair process. IAN axotomy decreases the quantity of bone calluses during the early stage of mandibular defect repair, but with no effect on the degree of mineralization. The shape of the defect area appeared to be aligned with the direction of local mechanical force produced by masticatory muscles. • Sensory denervation decreased the quantity of new bone in mandibular defect repair. • Visualization of mandibular defect repair was first achieved by Echarts. • Force from masticatory muscles affected direction of mandibular defect repair. • The critical size of full-thickness circular mandibular defect seemed ≤ 3 mm. [ABSTRACT FROM AUTHOR]