Objectives: This study aims to conduct a non-invasive measurement of the cutaneous temperature of selected masticatory muscle regions of volunteers with and without myogenous temporomandibular disorder (TMD), using infrared thermography.
Methods: 23 females (10 myogenous TMD volunteers and 13 controls) were recruited and studied. The temperature at the surface of the facial area over the anterior temporalis and masseter muscles was assessed by medical thermography, using regional lateral views and clinical examination.
Results: The temperature levels measured at the masseter and anterior temporalis muscle regions in myogenous TMD volunteers (32.85 ± 0.85 and 34.37 ± 0.64 ºC, respectively) were significantly lower (p < 0.05) than those measured in controls (33.49 ± 0.92 and 34.78 ± 0.44 ºC, respectively). Medical infrared imaging indicated a mean difference of 1.4 ºC between the masseter and anterior temporalis regions. Analysis of the comparison between the absolute and normalized mean temperatures was performed using the pairwise comparison of receiver operating characteristic curves, and no statistically significant difference was observed (p > 0.05). The sensitivity and specificity of the thermographic assessment for the masseter region was of 70% and 73%, respectively and for the anterior temporalis region was of 80% and 62%, respectively.
Conclusions: This method of evaluating masticatory muscle regions of this preliminary study seems to indicate that it can be used as an aid in complimentary diagnosing of TMDs.
Keywords: dentistry; infrared thermography; masticatory muscles; temporomandibular joint disorders.