How lip and tongue forces against incisors relate to craniofacial morphology in anterior open bite patients with a tongue thrust habit

Abstract

I measured lip and tongue forces against the central incisors in open bite patients who had a tongue thrust habit to investigate the relationship between these forces and craniofacial morphology. In open bite patients, only the tongue forces were abnormal. Forces on the cervix of the maxillary central incisors were smaller than normal while those on the cervix of the mandibular were larger. I compared craniofacial morphology and the tongue forces against the mandibular central incisors of open bite patients on swallowing. A high correlation was seen between tongue force and occlusal plane angle, interincisal angle, and L 1 to the mandibular plane angle. The results suggest that as the tongue position on swallowing becomes lower, the occlusal plane angle and L 1 to the mandibular plane angle become larger. However, the interincisal angle becomes smaller.