[Masticatory performance in adults related to temporomandibular disorder and dental occlusion]

Temporomandibular disorder and mastication.

To compare subjects who present temporomandibular disorders to a control group considering mastication and to analyze the related variables.

20 subjects with temporomandibular disorder (TMD group) and 10 controls--selection based on clinical examination and anamnesis--responded to a questionnaire on the self-perception of pain severity and presence of noise in the temporomandibular joints, muscle pain, otologic symptoms, headaches, and jaw opening difficulties. The subjects were also submitted to a clinical examination regarding the number of teeth and functional occlusion--measurements of jaw opening and jaw lateral excursions, occlusal interferences, occlusal contacts of the working and non-working-side, and mastication evaluation. Mastication was evaluated in terms of time needed to eat a stuffed cookie, number of chewing strokes and type (unilateral or bilateral). The maximum force needed at first to break the cookie, verified with a TA-XT2 Texture Analyzer (Stable Micro Systems), was of 4341.8 g. The groups were compared using variance analysis and the correlations between variables were calculated using the Pearson product-moment test.

Most of the control subjects presented bilateral pattern of mastication, whereas the TMD group tended to present the unilateral pattern. Masticatory type scores and laterality measurements were significantly higher in the control group. The TMD group presented higher means in terms of: age, time of chewing, number of chewing strokes and TMD severity. Chewing time and type were positively correlated with TMD severity and negatively correlated with number of occlusal interferences.

In the TMD group, chewing differed from the normal physiological standard. The number of occlusal interferences and the severity of TMD were variables correlated to chewing.