AN INFLUENCE OF OCCLUSAL PATTERN ON MASTICATORY MUSCLE ACTIVITY DURING TOOTH CLENCHING

Research Project

Project/Area Number	60480418
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 AND DENTAL UNIVERSITY
Principal Investigator	MIZUTANI HIROSHI TOKYO MEDICAL AND DENTAL UNIVERSITY, FACULTY OF DENTISTRY, 歯学部, 講師 (00014324)
Co-Investigator(Kenkyū-buntansha)	NAKAMURA KAZUO TOKYO MEDICAL AND DENTAL UNIVERSITY, FACULTY OF DENTISTRY, 歯学部, 助手 (90172395) ISHIHATA NOBUO TOKYO MEDICAL AND DENTAL UNIVERSITY, FACULTY OF DENTISTRY, 歯学部, 助手 (70114733) AI MINORU TOKYO MEDICAL AND DENTAL UNIVERSITY, FACULTY OF DENTISTRY, 歯学部, 教授 (00013889)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥6,200,000 (Direct Cost: ¥6,200,000) Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1985: ¥5,200,000 (Direct Cost: ¥5,200,000)
Keywords	PATTERN OF EMG / SOFTWARE OF INTEGRATED EMG ACTIVITY / TOOTH CLENCHING / CUSPID PROTECTED OCCLUSION / GROUP FUNCTIONED OCCLUSION
Research Abstract	IT IS COMMONLY ADMITTED THAT THERE ARE TWO TYPES OF OCCLUSAL PATTERNS ACCORDING TO THE CLASSIFICATION OF TOOTH CONTACT IN LATERAL POSITION; ONE IA GROUP FUNCTIONED OCCLUSION AND THE OTHER IS CUSPID PROTECTED OCCLUSION. HOWEVER, THE ORIGIN OR DEVELOPMENT OF THESE PATTERNS ARE NOT SUFFICIENTLY DISCUSSED. THIS STUDY IS MADE TO CLEAR THE ELECTROMYOGRAPHIC DIFFERENCE OF MASTICATORY MUSCLES DURING TOOTH CLENCHING BETWEEN THESE TWO PATTERNS. TEN HEALTHY MEN, FIVE WITH GROUP FUNCTIONED (GF) AND FIVE WITH CUSPID PROTECTED (CP), RANGING 23 TO 35 YEARS OF AGE WERE CHOSEN FOR THIS STUDY. SUBJECTS REPORTED NO HISTORY OF FUNCTIONAL DISTURBANCES OF MASICATORY SYSTEM. EACH SUBJECTS WAS SEATED IN AN UPRIGHT POSITION IN A DENTAL CHAIR AND ASKED TO PERFORM SEVEN MAXIMUM COMFORTABLE CLENCHES FOR EACH TASK. THE TASKS INCLUDED CLENCHING THE TEETH IN THE INTERCUSPAL, LEFT, RIGHT, RETRUDED, AND PROTRUDED POSITION. SIX MUSCLE CHANNELS WERE AVAILABLE FOR ELECTROMYOGRAPHIC RECORDINGS. IN ALL TEN SUBJECTS, BIPOLAR SURFACE ELECTRODES RECORDED MUSCLE ACTIVITY FROM THE SUPERFICIAL MASSETER MUSCLE, ANTERIOR AND POSTERIOR TEMPORAL MUSCLES BILATERLLY. RAW DATA STORED IN A VIDEO DATA RECORDER ARE INTEGRATED WITH 300 SEC SAMPLING TIME AND ANALYZED FOR EACH GROUP. THE RESULTS ARE AS FOLLOWS; 1. ACTIVITY IN THE INTERCUSPAL POSITION OF SIX MUSCLES IS THE GREATEST FOR BOTH GROUPS AND THERE IS NO SIGNIFICANT DIFFERENCE BETWEEN THEM. 2. SIGNIFICANT DIFFERENCE ARE OBSERVED IN LEFT AND RIGHT LATERAL POSITION BETWEEN TWO GROUPS. IN GF GROUP, IP RATIO OF SIX MUSCLES ACTIVITY SHOWS ABOUT 0.5, WHILE IN CP GROUP SHOWS ABOUT 0.25.