Comparison of three clinical techniques for evaluating joint sounds

Two-hundred two consecutive adult patients presenting to the University of Kentucky for general dental care screening were examined for temporomandibular joint sounds by three techniques: (1) lateral pole surface palpation, (2) digital palpation in the external auditory canal, (3) auscultation by a stethoscope. Sixty-nine patients reported joint sounds, but only 32 had sounds diagnosed by auscultation resulting in a 54% false-negative reporting rate. Stethoscopic auscultation was used as the standard to which the other two techniques were compared. The false-negative rate for auditory canal digital palpation was 71% and 77% for lateral pole surface palpation. Surface palpation had only a 2% false-positive incidence while auditory canal digital palpation had a 51% false-positive rate. There was poor agreement between the patients' subjective reporting and clinical exam by any technique. Using stethoscopic auscultation as the standard, both auditory canal and surface palpation had a very high false-negative rate, but only the auditory canal palpation had a poor false-positive incidence. Auditory canal palpation often produces TMJ sounds that are not heard with a stethoscope during normal opening and closure.