Osseous alterations in the condylar head after unilateral surgical directional change in rabbit mandibular condyles: preliminary study.

The purpose of this study was to investigate bony changes in the mandibular condyle when the surface not normally subjected to masticatory forces was subjected to functional loading using a unilateral surgical experiment. Fifteen male New Zealand white rabbits, divided into two groups, were used. Oblique vertical body osteotomies of the mandible and counterclockwise rotation (CCWR) of the proximal segment (PS) [six with 1 mm (group I), six with 3 mm (group II)] were performed on the right side. Osseous changes of condyles were analyzed using micro-computed tomography and histological evaluation four weeks postoperatively. The comparison was performed between condyles on the right and left sides. Since the left condyle (control) might be affected by the operation on the right side, the results were also compared with the healthy control (group III, n = 3, 6 condyles). CCWR of the PS led to osteoporotic changes of the condyle including significantly reduced bone volume and bone mineral density (p < 0.05), thin and small number of trabeculae (p < 0.05). In addition, thinning of condylar cartilage and reduced density of cartilaginous cells were observed. However, these changes were not affected by the amount of CCWR of the PS.