STATEMENT OF PROBLEM Qualitative and semi-quantitative methods have been developed for TMJ sound classification, but the criteria presented are completely inhomogeneous. analyzed using a mathematical technique known as the Fast Fourier Transform. RESULTS In this study Group I and Group II showed varied integral > 300 /< 300 ratios before and after the six-months recordings. Also, by the comparative study between the integral > 300 /< 300 ratios and the frequency spectrums, it was conceivable that this frequency spectrums showed comparable patterns at the same location that this joint sound occurred before and after the six-months recordings. while the frequency spectrums showed varied patterns at the different locations that this joint sound occurred before and after six-month recordings, it would possibly be due to the differences in the degree of internal derangement and/or in the shape of the disc. CONCLUSIONS It is suggested that clinicians consider the integral > 300 /< 300 ratios as well as the frequency spectrums to decide the starting-point of the treatment for TMJ sounds. Keywords: Joint Vibration analysis, Temporaromandibular joint, Joint sound, Electrovibratography INTRODUCTION Derangements of the condyle-disc complex arise from a breakdown of the normal rotational movement of the disc around the condyle. The thinning of the posterior border of the disc can cause the disc to be displaced in a more posterior position. With the condyle resting on a more posterior portion of the disc or retrodiscal tissues, an abnormal translatory shift of the condyle over the posterior border of the disc can occur during the opening. A click is usually associated with the abnormal condyle-disc movement and may be initially felt just during opening (single click) but later may be felt during opening and closing of the mouth (reciprocal clicking).1 Molinari et al.2 reported that occasionally a second clicking sound is heard during mouth closure (reciprocal click), because the posterior band of the disc slips forward off the condyle. Other clicking sounds can also be produced by irregularities or defects in the surface of the disc or by changes in the convexity of the condylar and/or Rabbit Polyclonal to RPS19 articular eminence. These sounds are usually less obvious than those caused by anterior disc displacement. They are also found at the same point of the temporomandubular joint (TMJ) traslator movement rather than at different points, as occurs with reciprocal clicking. Clicking and crepitation should be considered signs of morphological alterations, being indicative of anterior disk displacement with reduction3 and arthrosis, respectively. Electrovibratographic records and macroscopic examinations of articulations of corpses showed that 20% of the TMJs with clicking had 224785-90-4 supplier the disk displaced anteriorly and 22% of the TMJs with crepitation had arthrosis or disk perforation.4 Later recapture of the disk causes clicking at the end of mouth opening and indicates that this bilaminar zone is more affected.5 The microscopic aspects 224785-90-4 supplier of the disk surface can also be altered. 6 Qualitative and semi-quantitative methods have been developed for 224785-90-4 supplier TMJ sound classification, but the criteria presented are completely inhomogeneous.7-12 Thus, to develop more objective criteria for defining TMJ sounds, electroacoustical systems have been developed.7-9, 11-15 We used Joint vibration analysis (JVA) in the BioPAK system (Bioresearch Inc., Milwaukee, USA) as the electrovibratography, and Jaw tracker (JT)-3 device in the BioPAK system (Bioresearch Inc., Milwaukee, USA). Using JT-3 deivce allowed the computer to estimate where a joint vibration occurs in the open/close cycle and let us distinguish tooth contact from joint sound precisely. Ishigaki et al.17 reported a disc displacement with reduction generates a “click” in the lower frequencies (under 300 Hz) and a degenerative condition generates “crepitus” in the higher frequencies (over 300 Hz). In the previous study, we found that in an integral > 300 Hz /< 300 Hz ratio it is conceivable that the higher the integral > 300 Hz /< 300 Hz ratio number, a more advanced degenerative condition exists. Gallo et al.16 reported that TMJ clicking was subjectively and objectively stable over a period or 10 days. We found few studies about long term follow-up based on the frequency spectrum patterns associated with the integral > 300 Hz /< 300 Hz ratio. The aim of this study was to examine the TMJ sounds with repect to frequency spectra patterns.