Characteristics of temporomandibular joint vibrations in anterior disk displacement with reduction in adults.

The objective to the present study was to compare temporomandibular joint (TMJ) vibration in anterior disk displacement with reduction (ADDWR) in adults and to explore the diagnostic value of frequency spectrography of TMJ vibrations. Twenty-one patients with ADDWR formed the case group and were further divided into three subgroups according to the degree of disk displacement, and 26 symptomless adults formed the control group. The joint vibration was recorded during rhythmic maximal open-close jaw movement using JVA/JT, BioPAK (Bioresearch, Inc., Brown Deer, WI)). The sensitivity and specificity of the total integral for diagnosis of ADDWR was calculated. All TMJ vibration parameters, including total integral, integral>300Hz, integral<300Hz, >300/<300 ratio, peak amplitude, peak and median frequencies of the case group were significantly higher than that of the control group. Along with the degree of disk displacement, the amplitude and frequency of TMJ vibrations increased, and the total integral significantly increased. The total integral demonstrated high sensitivity and specificity for diagnosis of ADDWR (85.7% and 84.6%, respectively). TMJ vibration was significantly higher in adults with ADDWR than that in the symptomless control group. Different pathological stages of disk displacement have different TMJ vibrations.