[Clinical application of electrosonography in diagnosis of anterior disc displacement with reduction]

To investigate the electrosonography character of sounds emanating from anterior disc displacement with reduction of TMJ and the value of it in clinical diagnosis.The sounds from healthy TMJ, anterior disc displacement with or without reduction of TMJ, and osteoarthritis of TMJ were recorded and analyzed by K6-I system, then the data was used for diagnosis of anterior disc displacement with reduction in clinic.A special kind of waveform was found in the electrosonography of sounds from anterior disc displacement with reduction repeatedly, and seldom or not in sounds from healthy joints, anterior disc displacement without reduction or osteoarthritis of TMJ. The diagnostic sensitivity of anterior disc displacement with reduction by using electrosonography analysis was 77.2% and specificity was 93.3% when compared with the clinical diagnosis based on clinical appearance and radiography evidence.The special kind of waveform may be characteristic wave of sounds from anterior disc displacement with reduction of TMJ, which is useful for assistant diagnosis of anterior disc displacement with reduction in clinic.