MRI study of temporomandibular joint disc position in asymptomatic volunteers

To investigate the position of temporomandibular joint and its relationship with gender and side in asymptomatic volunteers by magnetic resonance imaging (MRI).

The study was based on bilateral MRIs of 30 asymptomatic volunteers, including 15 females and 15 males. A total of 60 temporamandibular joints were scanned oblique-sagittally and oblique-coronarily at mouth closed positions. Classification of the position of temporomandibular joint disc was identified and analyzed according to MRI.

Superior disk position was observed in 45 joints (75%), consisting of 20 in female plus 25 in male, and 23 at the right side plus 22 at the left side. Anterior disk position was observed in 7 joints (11.67%), consisting of 5 in female plus 2 in male, and 5 at the right side plus 2 at the left side. Lateral disk position was observed in 6 joints (10%), consisting of 3 in female plus 3 in male, and 2 at the right side plus 4 at the left side. Medial disk position was observed in 2 joints (3.33%), consisting of 0 in female plus 2 in male, and 0 at the right side plus 2 at the left side. No posterior disk position was observed in asymptomatic volunteers. There was no significant difference between genders or sides (P > 0.05).

Superior disk positionexists in most of asymptomatic volunteers. Disc displacement also existsin asymptomatic volunteers, however it is not associated with gender and side. Rotational anterolateral positon is the main type of disc displacement in asymptomatic volunteers.