Abstract
The study was undertaken to quantitatively evaluate the nature of TMJ sound of CMD patients. Four groups of subjects were clinically classified as follows: Group A, patients with audible TMJ sound; Group B, patients who were aware of TMJ sound and it was also perceptible to the clinician; Group C, patients who were not aware of TMJ sound but it was perceptible to the clinician; Group D, which consisted of subjects free of CMD symptoms. TMJ sound during opening and closing movements of all subjects were recorded with a contact microphone, frequency analysis was made and results were compared among the four groups.
1. For CMD patients, peaks in the area above 100Hz were found for groups A and B, whereas most of the peaks were below 100Hz for group C. Compared to group A, group B had fewer high frequency components and group C fewer than group B. On the other hand, the power spectra for group D had a pattern limited to a frequency below 100Hz and most of the subjects showed no peaks of frequency component.
2 . Group A had the highest cumulative 100% value and cumulative 80% frequency value, followed by group B, C and D. Siginficant differences were found between each and every respective group except between groups A and B, and between groups C and D for the cumulative 100% value, and between each and evey respective group for the cumulative 80% frequency value.
3 . From this results it was concluded that the differences in the nature of TMJ sound of CMD patients caused the differences in the pattern of power spectra, and the cumulative 100% value and particularly the cumulative 80% frequency value could be used as an effective index for quantitatively evaluating the nature of TMJ sound of CMD patients.
