Is it possible myogenic temporomandibular dysfunctions change the facial thermal imaging?

Infrared thermography is a functional examination that can document physiological changes such as abnormal cutaneous vasomotor activity in inflammatory and neurogenic pictures related to nociceptive and neuropathic pain by mapping the thermal distribution on the surface of the skin. Objective: The aim of this study was to verify if there is a facial thermal difference between the symptomatic and asymptomatic group for myogenic TMD according to the Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) in a European population sample. Material and methods: Sixty-one subjects between 20 and 40 years (26.2 ± 7.6 years) of both sexes were divided into two groups. The 28 facial thermo-anatomic points were selected and the values of minimum (Tmin), mean (Tmed) and maximum (Tmax) temperatures, average of hemiface temperatures of whole sample, temperature difference (ΔT(°C)) between groups and from these data an algorithm was formulated to separate the groups with greater accuracy. Results: There was an average difference of 0.3 °C of all points when comparing the two groups. The symptomatic group had lower maximum temperature for frontal and lateral views when compared to the asymptomatic group (p<0.05), and presented lower average temperature in frontal view (p<0.05). Symptomatic individuals for myogenic TMD presented a reduction of facial cutaneous blood flow corresponding to lower maximum temperature by the proposed method of analysis of thermal anatomical points. Conclusions: Infrared thermography showed potential to be a screening and complementary diagnostic examination method for patients with myogenic temporomandibular disorders in the daily clinic just by frontal face image.