Effects of controlled condylar rotation exercise on symmetrical mouth opening in patients with temporomandibular disorder

[Purpose] The purpose of this study was to determine the effects of a 4-week program of active condylar rotation exercise on the extent of the lateral mandibular shift during mouth opening in patients with temporomandibular disorder. [Subjects and Methods] Patients with temporomandibular disorder (n = 12; 7 men and 5 women) were recruited. The active range of temporomandibular motion was recorded using 3-dimensional ultrasound-based motion analysis. The paired t-test was used to assess changes in lateral mandibular shift before and after active condylar rotation exercise. [Results] The degree of the lateral mandibular shift during mouth opening and the mouth opening-lateral mandibular shift ratio were significantly lower after active condylar rotation exercise than before the exercise. [Conclusion] Active condylar rotation exercise may effectively reduce the degree of the lateral mandibular shift during mouth opening to produce symmetrical mouth opening in patients with mild temporomandibular disorder.