Post-traumatic TMJ internal derangement: impact on facial growth (findings in a pediatric age group)

Many clinical studies have shown how jaw injuries sustained during impact trauma to the face or mandible are the single most important cause of TMJ subsequent internal derangement. Proper function of the masticatory system is certainly the most influential variable in the TMJ remodelling; once a TMJ is internally deranged, adaptative or degenerative osteocartilagineous processes take place in the mandible, temporal bones and muscles. To evaluate relationships between consequences of post-traumatic TMJ internal derangement and disturbed facial skeleton growth in children, 25 patients (16 boys 9 girls), 14 year of age or younger, were selected out of a group of 74 and analysed. They all had been treated by physiotherapy and had undergone combined clinical and radiographic examination for five years. Symptoms included either individually or in various combination, pain, mechanical TMJ dysfunction and facial skeletal abnormalities, such as mandibular retrognathia and lower facial asymmetry manifested by chin deviation from the midline. Seventeen patients were found to have at least one abnormal and internally deranged TMJ on imaging studies; in twelve of them a mandibular asymmetry with chin deviation from the midline to the smaller or more degenerated TMJ was evident. Of the eight retrognathic patients, five were found to have bilateral TMJ derangement. In three patients both TMJ(s) were normal with normal facial structure. These data suggest that TMJ derangement in children may potentially have an impact on facial growth and lead to the development of retrognathia, with or without asymmetry, in many cases.