Peripheral muscle oxygenation and symptoms of stress in adolescents with and without temporomandibular disorder.

OBJECTIVE: To compare peripheral muscle oxygenation levels and the prevalence of psychological stress in adolescents with and without temporomandibular disorder (TMD). METHODS: A cross-sectional study was performed with adolescents submitted into two groups: those diagnosed with TMD (DG) and control (CG). Muscle oxygenation was measured by near-infrared spectroscopy in the masseter and upper trapezius muscles. Symptoms of stress were assessed by Lipp's Stress Symptom Inventory for Adults or Child Stress Scale. A Student t-test was used for intergroup comparisons and association between categorical variables by chi-square test, phi coefficient of correlation, odds ratio, and two-way ANOVA. RESULTS: Fifty-three adolescents were evaluated and a significant reduction was observed in the oxyhemoglobin level in the masseter muscle at rest (p = 0.04) and contraction (p = 0.02). A greater total hemoglobin level was found in the upper trapezius muscle at rest in DG (p = 0.03), with a significant difference in the tissue saturation index during contraction (p = 0.05) intergroup. Individuals in the DG were 4.523 times more likely to exhibit signs and symptoms of stress than in CG. CONCLUSION: Adolescents from DG showed reduced masseter oxyhemoglobin values at rest and during contraction and showed more signs and symptoms of stress than healthy controls. In the upper trapezius, DG showed higher values of total circulating hemoglobin, essential for greater blood flow and efficient maximum voluntary contraction. CLINICAL RELEVANCE: Changes in tissue oxygenation and stress in adolescents with TMD prompted the earlier treatment of this population to prevent disease progression into adulthood.

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.