Polyanne Junqueira Silva Andresen Strini

Assessment of thickness and function of masticatory and cervical muscles in adults with and without temporomandibular disorders

OBJECTIVE The aim of this study was to evaluate the maximal bite force (MBF), electromyographic (EMG) activity and thickness of the masseter, anterior part of the temporalis and sternocleidomastoid (SCM) muscles in a group of young adults with and without temporomandibular disorders (TMDs). DESIGN Nineteen individuals comprised the TMD group (6 males/13 females, aged 25.4±3.8 years), classified based on the Research Diagnostic Criteria for TMD (RDC/TMD), and 19 comprised the control group (6 males/13 females, aged 24.1±3.6 years). The MBF was determined with a transducer placed between the dental arches at the first molars level (N). The muscles were evaluated bilaterally at rest and during maximal voluntary clenching (MVC) by assessing EMG activity and performing ultrasonography (USG). The mean values of these measures for both sides of the mouth were used. The normality of the distributions was assessed by the Shapiro-Wilks test. Variables between groups and genders were compared using two-way factorial ANOVA test and correlated using the Spearman coefficient (α=0.05). Unpaired t test was used to compare variables between TMD subgroups. Logistic regression analysis was used to identify the variables associated with the presence of TMD. RESULTS MBF, EMG and USG data were similar among clinical groups and among TMD subgroups. The thickness of masseter and SCM muscles in the relaxed and clenching states were significantly higher in males than females. On the other hand, the EMG of the temporalis muscle in the rest state was significantly higher in females than males. Additionally, the MBF was positively correlated with the USG characteristics of masseter and SCM muscles, as well as with the EMG activity of masseter and temporalis muscles in the TMD group. In this group, there was also a positive correlation between the thickness of the masseter muscle and its activity. On the other hand, the thickness of the SCM muscle was negatively correlated with its activity. A lower MBF was independently associated with the presence of TMD. CONCLUSIONS Subjects with TMD exhibited similar values of MBF, thickness and electrical activity of masticatory and cervical muscles when compared with controls; positive correlations observed between these variables may suggest a muscular alteration in TMD patients and a co-activation of masticatory and cervical muscles during mandibular movement. This fact may also be confirmed by the negative association between bite forces and presence of TMD.

Computerized biophotogrammetry evaluation of asymmetry facial in patients with temporomandibular disorders

Introduction: the protocols of evaluation of the asymmetry facial in patients with temporomandibular disorders are, in general, realized by using cephalometric analysis, which provide the visualization, measurement and analysis of the hard tissue only. The facial analysis by computerized biophotogrammetry has been used as an auxiliary manner of diagnostic, not exposing the patient to harmful radiation, promoting the evaluation of craniofacial and muscular structures and fat layer disposition. Aim: evaluate the facial asymmetry in patients with temporomandibular disorders by computerized biophotogrammetry. Material and methods: the sample was 36 patients (31 women and 05 men) and 11 controls (06 women and 05 men) with temporomandibular disorders. For selection and classification of the sample, the Clinical Index of Fonseca (1994) was used, according to physical, dentistry and physiotherapic examination. Results: significant differences (p=0,041) were found between the mouth angle and the right and left sides in patients with temporomandibular disorders. Conclusion: alteration in facial symmetry can be observed in patients with temporomandibular disorders and it is located in lower portion of face, mainly in maxillary, mandibular and menton regions.