Intra-articular and skin surface temperature of human temporomandibular joint

Ten subjects, five women and five men, without symptoms or signs of disorder in the stomatognathic system were examined for intra-articular and skin surface temperature of the temporomandibular joint (TMJ). The temperature measurements were made with thermocouples at three depths within the joint (10, 15, 20 mm) and at five locations on the skin surface over the joint. The intra-articular mean temperature was 36.0 degrees C at 10 mm, 36.1 degrees at 15 and 36.3 degrees at 20 mm. The average difference in intra-articular temperature between the right and left sides was 0.2 degrees C. The intra-articular temperature was not correlated to room temperature. The average skin surface temperature over the center of the condyle was 35.1 degrees C and the difference between skin surface temperature over the condyle and intra-articular temperature at 20 mm was 1.2 degrees C. The average difference between the right and left sides for skin surface temperature was 0.3 degrees C. The intra-articular temperature showed a negative correlation to the skin surface temperature (r = -0.54). The results of this study show that the intra-articular temperature range of the TMJ is rather narrow, about 1.2 degrees C (35.7-36.9 degrees C) and that the difference between sides is less than 0.6 degrees C.