Cephalometric characteristics in patients with hyperplasia of the tendon and aponeurosis of masticatory muscles who have square mandibles

Abstract

Hyperplasia of the tendon and aponeurosis of masticatory muscles (HyTAM) is a new disease entity characterized by chronic severe mandibular hypomobility with a square mandible caused by contracture of the masticatory muscles resulting from hyperplasia of tendons and aponeuroses. We investigated the skeletal features of HyTAM using cephalometric analysis. Angular analysis showed that the gonial angle (p<0.01), FMA (p<0.05), cant of the occlusal plane (p<0.01) and Y-axis (p<0.001) were significantly less than the standard values. The saddle angle (p<0.05) and facial angle (p<0.001) were significantly greater than the standard values. Linear analysis showed that S-Go/N-Me was significantly less than the standard value (p<0.05). The typical patient with HyTAM is characterized by a square mandibular configuration. Based on our findings, it is reasonable to suppose that HyTAM is marked by a lower gonial angle. Our findings also indicated that HyTAM patients not only showed hyperplasia of the tendon and aponeurosis of masticatory muscles, but also had unique facial skeletal appearances such as jaw deformity.