The Analysis of Condylar Movements Under the Masticatory Loading

Research Project

Project/Area Number	63480427
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	補綴理工系歯学
Research Institution	Tokyo Medical & Dental University
Principal Investigator	SATO Takahiro Tokyo Medical & Dental Univ., School of Dentistry, Research Associate, 歯学部, 文部教官助手 (70178747)
Co-Investigator(Kenkyū-buntansha)	KURIYAMA Minoru Tokyo Medical & Dental Univ., School of Dentistry, Research Associate, 歯学部, 文部教官助手 (90134725)
Project Period (FY)	1988 – 1989
Project Status	Completed (Fiscal Year 1989)
Budget Amount *help	¥6,300,000 (Direct Cost: ¥6,300,000) Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1988: ¥5,300,000 (Direct Cost: ¥5,300,000)
Keywords	Craniomandibular disorders / Condylar movement / Periotest / Selspot system / Masticatory muscle / Functional occlusion system / EMG / 咀嚼運動
Research Abstract	It has been generally accepted that the overloading on the condyle during the mastication plays the main role as the etiologic factor of the craniomandibular disorders. But the condylar movement cannot be identified directly because of its location and the details are not clear. The purpose of this investigation is to analyze the functional occlusion system systematically which is composed of three factors, that isothe masticatory muscle,TMJ, and the periodontium and to clarify the relationship between condylar position and the masticatory process. For this purpose, we have developed a new measuring system " Selspot system" which can measure the condylar movement, the mandibular movement, and EMGs of masticatory muscles simultaneously very accurately. In addition to these measurements,the dynamic function of the periodontium was measured with the PERIOTEST. The results of the measurements of normal subjects are as follows : 1. At the early stage of the mastication, EMG activity showed its peak when the condyle located more anteriorly than intercuspal position. 2. At the late stage of the mastication, EMG activity showed its peak when the condyle located at the deepest point in the articular fossa. 3. The masticatory process was changed according to the texture of the food. 4.The Periotest value has proved to be calculated from the contact time between the measuring head and the tooth , and it showed the dumping effect of the periodontium. 5.There was a close relationship between the the clinical degree of tooth mobility and the Periotest value. After this, we will study the craniomandibular patients and will make clear the relationship between the overloading on TMJs and the symptoms of craniomandibular disorders.