下がく振動からみた下がく安静位の機能的意義

Abstract

This study is based on the notion that the mandibular oscillation, which is part of mandibular fluctuation at the lower incisal point, reflects the functional condition of the stomatognathic system. The purpose of this study was to investigate the significance of the mandibular oscillation in functional diagnosis of the stomatognathic system.The subjects of this study were 7 males with a normal tooth alignment and normal occlusion and 2 males with some clinical dysfunctional symptoms in stomatognathic system. The equipment of this study, appling a MKG, is able to record a mandibular oscillation and interocclusal distance. Recordings were made on 7 normal subjects 5 times within one day, at the same time on every 5 days period, before and after tooth contact, with voluntary changing vertical and lateral jaw positions, and on 2 subjects with stomatognathic dysfunction before and after Myo-monitor pulsing and insertion of occlusal splint. The analogue data obtained during these recordings were observed visually, and in addition correlation analysis was performed on them, then the following results were obtained.1. Variation was found, in all 9 subjects, of each mean amplitude of mandibular oscillation at rest. Those mandibular oscillations were made up of several frequencies of oscillation, therefore, mandibular oscillations in 7 normal subjects were more periodic than those in 2 subjects with stomatognathic dysfunction.2. Intraindividual variations of mandibular oscillations at rest both within one day and over a period of 5 days were found to be small compared to those of free way space.3. Mandibular oscillations at rest after tooth contact would become aperiodic for a while and then became periodic again.4. Mandibular oscillations became aperiodic with changing vertical and lateral jaw positions.5. Mandibular oscillations at rest after Myo-monitor pulsing became more periodic than before pulsing, and the free way space also increased.6. After insertion of an occlusal splint, mandibular oscillations became periodic, and the free way space also increased.7. The difference of the periodicities of mandibular oscillations could be significant with better objectivity if correlation analysis of the signals is employed in this study.