Mandibular movement and frontal craniofacial morphology in orthognathic surgery patients with mandibular deviation and protrusion

The present study was conducted to investigate the relationship between mandibular movement (lateral excursion and masticatory movements) and craniofacial morphology in 16 patients with mandibular deviation, using a six degrees-of-freedom measuring device. (i) Mandibular deviation was found to be significantly related to frontal maxillary and occlusal plane angles. (ii) Three-dimensional non-working condylar and incisal path lengths were longer during the lateral excursion to the non-deviated side than to the deviated side, and the incisal path moved antero-inferior. (iii) The lateral motion range of the incisal path was wider during masticatory movement on the non-deviated side than on the deviated side, and the molar and non-working condylar path lengths corresponding to the lateral range of the incisal path were also longer on the non-deviated side. The group with posterior crossbite showed a significantly smaller horizontal range of incisal path, and also significantly smaller frontal projected incisal and molar path angles during masticatory movement on the deviated side than on the non-deviated side. These results suggest that lateral excursion and masticatory movements could be related to craniofacial morphology and posterior crossbite.