Abstract
We succeeded in making comparatively simple and cheap masticatory movement observation equipment of connecting a small 2 axis acceleration sensor to a personal computer through a general-purpose interface, without special equipment.
Since only one sensor is attached to the chin and X-Y 2 axis data is obtained simultaneously, this device can record masticatory movement by detecting changes in 2-dimensional acceleration.
Using this equipment two subjects with natural dentition and two subjects with full dentures were examined. Chewing gum mastication was recorded for about 10 seconds, and observation of the 2 dimension-original wave form of the mastication movement locus, frequency component analysis by FFT, and chaos analysis were tried. We had a purpose of examining the possibility of clinical application by this system.
Consequently, according to the acceleration movement graph, natural dentition subjects had a small amplitude, whereas complete denture wearers had a wide amplitude. Moreover, when the FFT frequency analyses were compared, the complete denture wearers had movement with a regular frequency component, and had a steady wave form. The natural dentition subjects did not have a regular frequency component, and did not show any special tendency.
Also in chaos analysis, the complete denture wearers were unstable and there was little complexity. Especially, on the vertical axis of complete denture wearers, although the jaw was moved greatly, when seen from the viewpoint of complexity, the movement was simple. Conversely, the natural dentition subjects moved their teeth horizontally during masticatory movement, and had gentle motion and with free complexity in the after bite.
As mentioned above, this equipment allowed us to observe mastication movement clinical by in spite its comparative simplicity.
