Dentofacial vertical proportions and overbite in myopathy syndrome

Abstract

Skeletal malocclusion with anterior open bite is much more difficult to correct with orthodontics than anteroposterior malocclusion. Anterior open bite induced by skeletal factors is primarily caused by congenital defects or internal diseases. It tends to worsen over time and is associated with persistent abnormality of the craniofacial complex.
We attempted to clarify the relationship between congenital myopathy (the deficiency of type II fibers with minicore) and skeletal Class Ⅲ patients with anterior open bite, as well as, the relationship between vertical facial proportions and over bite.
We found that anterior facial height is significantly greater in this myopathy patient than in skeletal Class III cases with anterior open bite (the control group). In addition, the mandibular body showed more severe clockwise rotation in this myopathy patient than in the control group. Also, descent of the palate in the posterior region was significantly greater in this myopathy patient. We also found that the depth of the palate and the ratio between the depth of the palate and the width of the maxillary dentitions were significantly greater in this myopathy patient than in the control.
These results seem to imply that overbite might be affected by morphological and spatial changes in the palate caused by a deficiency in muscle activity. The morphology and the depth of the palate seemed to be very useful in assessing relations between the vertical proportions of the dentofacial complex and the overbite.Shika Igaku(J Osaka Odontol Soc) 2003 Jun; 66(3): 211-219.