[Acoustical analysis of occlusal sound--transfer functions of oral cavities and characteristics of waveform of occlusal sound].
The purpose of this study is to clarify the acoustical characteristics of the occlusal sound. An FFT analyzer was used to analyze the transfer functions of the oral cavities. The characteristics of the waveform of the occlusal sound were investigated by the time-frequency analysis. The results obtained were as follows: (1) There were three peaks in the low frequency area of the transfer functions of the oral cavities. The duration of the impulse responses of the oral cavities had a wide variation among the individuals. (2) The waveform of the occlusal sound by air-conduction was proved to consist of two components. One was the teeth collision sound produced by the collision of the teeth in the oral cavity and emitted directly out from the oral cavity. The other was the reverberation considered to be formed mainly by the resonance system in the oral cavity. (3) By the time-frequency analysis, the teeth collision sound could be distinguished clearly from the reverberation; the former was recognized as the component where the energy existed up to the high frequency area, while the latter was recognized as the component where the energy existed only in the low frequency area. (4) It was suggested that the teeth collision sound, after separating from the reverberation, should be analyzed for the purpose of obtaining further information about the functional condition of the occlusion from the occlusal sound.
Sugisaki
S
S
1st Department of Orthodontics, Faculty of Dentistry, Tokyo Medical and Dental University.
Kawaura
J
J
Suzuki
H
H
Handa
H
H
Miura
F
F
D000328:Adult; D001732:Bite Force; D006801:Humans; D008297:Male; D008409:Mastication; D009055:Mouth / Q000502:physiology*; D013016:Sound; D014070:Tooth / Q000502:physiology