Masticatory muscles electrical activity, stress and posture in preadolescents and adolescents with and without temporomandibular dysfunction.

Objective: To verify the difference between the masticatory muscles' electrical activity, stress signals and the posture of preadolescents and adolescents with and without temporomandibular dysfunction (TMD).

Methods: 24 preadolescents and adolescents aged between 11 and 18 years old were divided into two groups, TMD group (TMDG) and control group (CG). All subjects were submitted to anthropometric measurements, psychological stress analysis, temporomandibular joint clinical evaluation and TMD verification; postural evaluation and masseter and temporal muscles electrical activity analysis during chewing. For statistical analysis, the Student's t-test or Mann-Whitney U test were used according to data distribution.

Results: There was a significant difference between the groups for the electrical activity of the right temporal muscles (7.43% ± 2.92 vs. 11.71% ± 5.37) and left (7.70% ± 4.04 vs.11.44% ± 4.03) in the inactive period of chewing between CG and TMDG, respectively. There was no difference in stress or posture variables between groups.

Conclusions: During the inactive period of chewing, there was greater activation of the temporal muscles in the TMDG. Female gender was prevalent in TMDG. The study participants showed signs of stress, regardless of the group. The posture and TMD relationship still need to be studied.