Jaw dysfunction is associated with neck disability and muscle tenderness in subjects with and without chronic temporomandibular disorders.

PURPOSE: Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. METHODS: Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. RESULTS: The correlation between jaw disability and neck disability was significantly high (r = 0.915, P < 0.05). The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r = 0.32-0.65). CONCLUSION: High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD.

Analysis of postural oscillation in children with cerebral palsy.

It is believed that static balance undergoes changes in children with cerebral palsy (CP). Thus, we analyzed postural oscillation in 19 children with the aim of comparing balance between healthy children and those with CP. The sample was divided into two groups--one with 10 children diagnosed with diparetic CP (CPG) and a control group (CG) with nine healthy children, all capable of remaining in an orthostatic position without support and obeying spoken commands. The assessment of postural oscillation was performed with the children barefoot, arms alongside the body and looking toward a fixed point while standing on an unrestricted base for the feet. Data collection was performed using a TEKScan force platform with 30-second duration for each condition. The children had an average age of 7.9 years (+/- 2.07) in the CPG and 7.5 years (+/- 1.58) for the CG. Postural oscillation data in the anterior-posterior and medial-lateral directions were analyzed using the Data Analysis and Technical Graphics Origin 6.0 program. Statistical analysis of the mean oscillation value in the conditions of eyes open and eyes closed did not differ significantly between groups. However, there was a significant difference in mean anterior-posterior oscillation between groups (p = 0.00). The groups behaved similarly with regard to the visual deprivation. We conclude that children with CP exhibit less postural oscillation in comparison to healthy children under the same conditions.

Electromyographic study of stomatognathic system muscles during chewing of different materials.

OBJECTIVE: The aim of this study was to compare the behavior of the major chewing muscles (anterior temporalis, masseter and suprahyoid muscles) by using two commercial chewing gums (A and B) and two insipid materials (cotton ball and Parafilm M) through analysis of electromyographic signals. METHOD: Ten female young adult subjects, aged from 18 to 27 years, with normal occlusion and no history of craniomandibular disorder were studied The masticatory activity was performed with the subjects comfortably sat so that the Frankfurt plane was parallel to the floor. Electromyographic exams were carried out using bipolar surface passive mini-electrodes positioned on the anterior temporalis, masseter, and suprahyoid muscles. The subjects were guided to chew bilaterally and simultaneously each one of the materials, in aleatory sequence. For the study of the masticatory activity the electromyographic signals were processed through rectification, linear envelope and normalization, so that the coefficient of variation obtained from the procedure was comparatively analyzed. All data were submitted to analysis of variance (uni- and multi-varied). RESULTS: The results of this study indicated that the best materials for electromyographic studies on the chewing were Parafilm and cotton ball because they demonstrated the smallest coefficients of variation. CONCLUSION: In addition, Parafilm showed the best palatability. In a general way, these materials are indicated for the accomplishment of electromyographic exams, since they demonstrated a smaller coefficient of variation as compared to the other materials.

Preliminary rapport on head posture and muscle activity in subjects with class I and II.

Forward head posture may cause alterations in the stomatognathic system, including changes in the muscle activity of the masticatory muscles and dental occlusion alterations. Considering the need for further understanding of the relationship between the stomatognathic system and the cervical region, the purpose of this study was to analyse the head posture and the electromyographic (EMG) activity of the anterior portion of temporal and masseter muscles bilaterally among bruxist's subjects with different dental occlusion classifications using the Angle method. The study consisted of 20 female volunteers, between the ages of 17 and 27 years. They were separated into two groups (class I and class II occlusions) according to a dentist-performed evaluation. An assessment of forward head posture was conducted using a photographic technique (angular calculus) combined with a clinical analysis. In the EMG analyses, active differential surface electrodes (Ag) were utilized and were placed bilaterally on the belly of masseter and temporal muscles, perpendicular to the muscles fibres. The EMG signal recorded during bilateral isotonic mastication, was presented using the Root Mean Square and was processed by Matlab software. The results indicated that the EMG responses of temporal and masseter muscles tend to be modified by occlusion alteration class II. Subjects with class II occlusion tended to present more occurrence of forward head posture with alterations in the muscle activity pattern between masseter and temporal muscles.