Prevalence of structural bony change in the mandibular condyle.

Estimated on data derived from a longitudinal study of 172 orthodontic subjects, structural bony change in the mandibular condyle occurs in 5% of the individuals documented from childhood to adulthood. The first appearance generally was between 12 and 16 years of age. Differential diagnosis based upon signs and symptoms of CMD registered simultaneously, as proposed in the 1990 guidelines for craniomandibular disorders appeared to be inconsistent. To illustrate how suddenly the process of bony change may proceed, a case report is presented in which a severe change transpired within a 1-year interval in a 13-year-old patient.