The effect of occlusal relationships on the occurrence of sounds in the temporomandibular joint.

The aim of this investigation was to determine the influence of occlusal relationships on the occurrence of sounds in the temporomandibular joint. A group of 100 male subjects aged 24-52 years (X = 35.03+/-6.92) was examined. Analysis of occlusion included determination of the number of existing teeth, number of teeth in occlusion, overbite and overjet, type of occlusion, mediotrusion interferences, relationship of the retruded contact position (RCP) to intercuspal position (ICP), and the amount and direction of sliding from RCP to ICP. Sound was registered by means of a stethoscope and classified according to its character in click or crepitation. Sound was present in 29% of subjects. In 28% of cases it was registered as click and in 2% of cases as crepitation. One subject had simultaneous click and crepitation. The results of the statistical analysis indicate that overbite, type of occlusion, existence of mediotrusion interferences, the relationship of RCP to ICP, and the amount and direction of sliding from RCP to ICP do not have an influence on the occurrence of sounds. The risk of the occurrence of crepitation is significantly increased in the case of the loss of more than 5 teeth, and in the case of horizontal overbite larger than 7.5 mm (p<0.05).