Prevalence of class III malocclusion and crossbite among children and adolescents with craniomandibular dysfunction.

Numerous studies have been devoted to the causes of craniomandibular dysfunction (CMD). This investigation addressed the effect of class III malocclusion and crossbite on CMD based on a sample of 115 prepubertal and adolescent patients of both sexes. Although class III malocclusion only accounted for 12.2% of the total sample, thus, being the smallest group, the percentage of crossbite (71.4%) among these patients was disproportionately higher than among the other classes. Of the total sample, the prevalence of crossbite was 30.4%. We compared these findings to a large-scale (n=4727) study by Thilander et al. (2002), who reported a strikingly high percentage of class I patients compared to our findings (72.7% versus 27.8%) and a lower percentage of crossbite cases (8.0% versus 30.4%). In accordance with the "orthodontic risk child" concept by Grabowski et al. (2007) and Stahl et al. (2007), we conclude that class III malocclusion and crossbite are keys in the pathogenesis of CMD.