The advantageous direction of jaw movement for releasing TMJ intermittent lock

Abstract

The purpose of this study was to clarify which direction of jaw movement is advantageous for releasing TMJ intermittent lock. The subjects included ten patients with TMJ intermittent lock who could not open their mouths fully in habitual opening paths (habitual opening), but could open fully in intentionally winding opening paths (winding opening). The following movements were analyzed: habitual opening, winding opening, lateral border opening to the contralateral side (contralateral opening), lateral border opening to the affected side and anterior border opening. The incisal points in winding opening tended to trace antero-lateral paths that were shifted toward the side opposite the affected joints in comparison with habitual opening. In addition to winding opening, the success rate in releasing locking of contralateral opening was significantly greater than that of habitual opening. The findings demonstrated that contralateral movements directed toward the nonaffected side are advantageous for releasing the intermittent lock. The patients will have a better chance of releasing the intermittent lock by themselves, when opening path shifted to the nonaffected side is recommended as the first choice.