FREQUENCY SPECTROGRAPHIC ANALYSIS OF BONE CONDUCTED CHEWING SOUNDS IN PERSONS WITH NATURAL AND ARTIFICIAL DENTITIONS

Bone conducted chewing sounds picked up by a specially designed device were recorded from three different facial bony locations in two age and sex matched groups of subjects with natural and artificial dentitions. Frequency spectrographic analysis revealed that, although the sounds were louder in subjects with natural dentition, crisp and soggy textures could be equally well differentiated by their noise levels in both groups. The use of a denture adhesive restored the chewing noise of denture wearers to that observed in the natural dentition group. There was a marked degree of mechanical impedance in the transmission of sound from the site of masticatory impact to distant cranial points. Breakdown of particle size during chewing was accompanied by declines in noise levels.