The lateral pterygoid muscle affects reconstruction of the condyle in the sagittal fracture healing process: a histological study.

The purpose of this study was to verify the role of the lateral pterygoid muscle in the reconstruction of the condyle shape during the sagittal fracture healing process by histological methods. Twenty-four adult sheep underwent an osteotomy to create a sagittal fracture of the left condyle; the sheep were then divided randomly into two groups. The lateral pterygoid muscles of the sheep in the experimental group were maintained on the internal poles of the condyles, and their functions remained stable. The lateral pterygoid muscles of the sheep in the control group were cut, and their functions were blocked. The shape, erosion, and calcification of the condyles were observed and measured after 4, 12, and 24 weeks of healing (n=4 from each group). The condyles were then submitted to haematoxylin and eosin, Ponceau S, and Sirius red studies. The results of the histology studies showed increased bone formation in the experimental group in which the functions of the lateral pterygoid muscle remained the same. The results of this study suggest that the lateral pterygoid muscle affects the reconstruction of the condylar shape during the healing process of a sagittal fracture of the mandibular condyle, and may even be involved in the formation of ankylosis.