Bite force determination in adolescents with and without temporomandibular dysfunction.

The aims of this study were to compare bite force in adolescents with and without temporomandibular dysfunction (TMD), and to investigate the influence of gender, age, height and weight on bite force magnitude. The TMD was evaluated using a self-report questionnaire and the Craniomandibular Index, which has two subscales, the Dysfunction Index and the Palpation Index. Subjects with lower and upper extremity values were used to integrate the control (Group I -n = 20) and TMD (Group II -n = 20) groups, respectively. In addition, the TMD group should have at least one subjective symptom. Bite force was determined with a transducer, which consisted of a pressurized rubber tube connected to a sensor element (MPX 5700 - Motorola SPS, Austin, TX, USA). Analysis of covariance, Pearson's coefficient, Mann-Whitney and t-tests were applied to analyse the data. The results showed that Group II presented smaller values for bite force than Group I and boys had greater values than girls in Group II (P < 0.05). Bite force values were significantly smaller for girls between groups (P < 0.05), whereas for boys there was no statistical difference. Weak positive correlation between bite force and weight, height and age (P > 0.05) and significant negative correlation between bite force and Palpation and Craniomandibular Indexes (P < 0.05) were found. It was concluded that decreased bite force was correlated with TMD in girls, primarily with muscle tenderness.