Dentofacial characteristics of growing patients with Duchenne muscular dystrophy: a morphological study.

Occlusal traits and craniofacial morphology were studied in growing patients with Duchenne muscular dystrophy (DMD). Sixteen patients from 6 to 20 years of age were examined and compared with 16 healthy male individuals matched according to age. The dental arches and occlusal traits of both groups were analysed on dental casts and compared with the norms of healthy individuals from the literature. Lateral cephalograms of the patients were compared with normal individuals by using scored values based on standard deviations in order to compensate for heterogeneity in the age of the subjects. Statistical analysis was undertaken for continuous variables with a paired Student's t-test and non-continuous variables with a chi-square test. Linear regressions were used to evaluate the influence of age. A high prevalence of malocclusions was found, including posterior crossbites, anterior and lateral open bites, a tendency towards mesio-occlusion due to a skeletal Class III malocclusion, and dental compensations of the Class III relationship by retrusion of the lower incisors. Both upper and lower arches were widened posteriorly. The lower arches were even wider than the upper arches, resulting in frequent posterior crossbites. No significant skeletal vertical deviations were observed in this group of DMD patients, except for the maxillary plane angle (NL/NSL) that was larger than normal, while the anterior upper face height (NSp) was smaller. However, no difference was found in lower face height. The posterior enlargement of the dental arches and the dentoalveolar development towards an Angle Class III relationship were significantly related to age and found more frequently among the older subjects.