The correlation study on mandibular deviation and cervical vertebrae posture in patients with mandibular asymmetry

Abstract Background: To explore the degree of skeletal mandibular deviation and the change of mandible position in patients with mandibular deformity and its correlation with cervical posture in patients with jaw deformity using CBCT and to provide the reference for clinical diagnosis and treatment planning. Methods: CBCT images from 30 adult patients with skeletal mandibular deviation and 30 adult individuals with facial symmetry were analyzed and imported in Invivo 5 to reconstruct a 3D hard-tissue surface model. A reference frame was set up and 20 measurements of the mandible and cervical vertebrae were performed to calculated. The difference between the three-dimensional position of the mandible and the posture of cervical spine were analyzed in patients with mandibular asymmetry and normal people. Results: Compared with the normal maxillofacial symmetry groups, there were significant differences in the degree of skeletal mandibular asymmetry and cervical deviation in the mandibular deviation groups(P ＜ 0.05). A strong positive, linear correlation was found in patients with mandibular deviation between the deviation of the mandible and cervical vertebrae posture. Conclusion: There is an inherent correlation between the occurrence of mandibular deviation and the deflection of cervical posture, and they interact on each other. The deformity of mandible affects the three-dimensional posture of the cervical vertebra and can cause different degrees of cervical deflection. The degree of mandible deviation and cervical vertebrae posture in patients with mandibular asymmetry are greater than those in individuals with facial symmetry. Compared with the patients with normal jaw, the deformity among the patients with skeletal mandibular asymmetry has a tendency to tilt forward and bend forward. The abnormal posture of the cervical spine will also affect the three-dimensional position of the mandible, causing the lower 1/3 of the face to appear facial asymmetry with the deflection of the head and neck posture.