| Co-Investigator(Kenkyū-buntansha) |
TANNE Kazuo Osaka University, Orthodontics, Assistant Professor, 歯学部附属病院, 講師 (30159032)
YOSHIDA Kenmi Osaka University, Orthodontics, Associate Professor, 歯学部, 助教授 (60107068)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Research Abstract |
Several hypotheses have been proposed to explain the mode of action of the activator. Since the most variable aspect of appliance design is the construction bite, the effect of treatment could be evaluated on this basis. Furthermore the construction bite determines the sagittal and vertical displacements of the mandible and the degree and direction of appliance activation.
The purpose of this study was to investigate the relationship between the functional-jaw orthopedic forces of the activator and the construction bites.
Four children with functional Class III malocclusion were used as the subjects. Four types of the activator were designed to retract the mandible to an edge-to-edge anters-posterior relationship at the 2, 4, 6, and 8mm interincisal distances. The rosette straingauges were set into the median plane of the activator. Simultaneously, strain, efectromyogram(EMG), and electroencephalogram(EEG) were checked. For examination of the relationship with strain, EMG activity was recorded from the masseter muscle and the anterior fibers of the temporalis muscle. In order to score the sleep stages. EEG(C3-A2), EMG activity from mentalis muscle. and eye movements(EMG from lateral to the outer canthus) were recorded.
The results were as follows; 1.With the higher construction bite, the magnitude of maximum strain was increased, and the rotated angle was turned from the original position with the clockwise rotation. 2.In the aspect of EMG activities under several kinds of construction bites, they could be divided into three patterns, superior masseter muscle, superior temporalis muscle, and both the superior masseter and temporalis muscle. Under four types of construction bites, the magnitude of maximum strain in the pattern of both the superior masseter and the temporalis muscle was the greatest of the EMG activity pattern. Moreover the angle of it in that of superior temporalis muscle was the largest.
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