Ultrasound imaging of the TMJ disc in asymptomatic volunteers. Preliminary report.

The position of the TMJ disc in 23 asymptomatic volunteers was determined by ultrasonography imaging. A very low incidence (2.1%) of internal derangements was revealed. The results are discussed in the light of current concepts on the aetiology of TMJ internal derangements. Since ultrasound imaging makes possible noninvasive dynamic investigation of the TMJ arrangements, performance of a prospective long-term study including a sufficiently large group of volunteers is suggested to clarify further the real incidence of TMJ internal derangements.