Temporomandibular disorders. Part III: Occlusal and articular factors associated with muscle tenderness

Two complete classes of freshman dental and dental hygiene students, 120 men and 102 women (mean age 23.9 years), were assessed for the presence of masticatory pain or dysfunction by questionnaire, clinical examination, and evaluation of dental casts. The purpose of these examinations was to determine potential relationships between clinical muscle tenderness, occlusal relationships, and signs of TMJ dysfunction. Awareness of muscle tenderness increased with the number of muscle sites involved ( p ≤ .025) but 80% of clinically tender subjects were unaware of any tenderness ( p ≤ .01). In comparison, subjects with generalized clinical muscle tenderness more often reported TMJ clicking that was not verified at the time of clinical examination ( p ≤ .001). Occlusal factors, except in highly selective categories, were not associated with muscle tenderness. All subjects with moderate or severe TMJ tenderness had clinically tender muscle sites, whereas subjects with generalized muscle tenderness (≥4 sites) had more severe TMJ tenderness ( p ≤ .01). Subjects with localized ( p < .05) or generalized muscle tenderness ( p < .05) had more TMJ clicking than those without muscle tenderness. TMJ clicking was reported more commonly than muscle pain among subjects who were clinically determined to have both muscle tenderness and TMJ clicking ( p ≤ .001). TMJ dysfunction was verified more often in subjects with more localized muscle tenderness ( p ≤ .025). Although occlusal factors were not good predictors of muscle tenderness, intracapsular signs of TMJ disorders and muscle tenderness were often associated.