Women with more severe degrees of temporomandibular disorder exhibit an increase in temperature over the temporomandibular joint

Abstract

Aim: The purpose of the present study was to correlate the degree of temporomandibular disorder (TMD) severity and skin temperatures over the temporomandibular joint (TMJ) and masseter and anterior temporalis muscles. Materials and methods: This blind cross-sectional study involved 60 women aged 18–40 years. The volunteers were allocated to groups based on Fonseca anamnestic index (FAI) score: no TMD, mild TMD, moderate TMD, and severe TMD (n = 15 each). All volunteers underwent infrared thermography for the determination of skin temperatures over the TMJ, masseter and anterior temporalis muscles. The Shapiro–Wilk test was used to determine the normality of the data. The Kruskal–Wallis test, followed by Dunn’s test, was used for comparisons among groups according to TMD severity. Spearman’s correlation coefficients were calculated to determine the strength of associations among variables. Results: Weak, positive, significant associations were found between FAI score and skin temperatures over the left TMJ (rs = 0.195, p = 0.009) and right TMJ (rs = 0.238, p = 0.001). Temperatures over the right and left TMJ were significantly higher in groups with more severe TMD (p < 0.05). Conclusion: FAI score was associated with skin temperature over the TMJ, as determined by infrared thermography, in this sample. Women with more severe TMD demonstrated a bilateral increase in skin temperature. Keywords: Temporomandibular joint disorders, Thermography, Skin temperature, Skeletal muscle