| 1705 Role of Teeth Clenching on Body Equilibrium | ||
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S. TANAKA1, Y. YOKOYAMA2, T. ISHIJIMA3, Y. KIBANA1, H. KOSHINO2, and T. HIRAI2, 1Health Sciences University of Hokkaido, Ishikari-Tobetu,Hokkaido, Japan, 2Health Sciences University of Hokkaido, School of Dentistry, Ishikari-Tobetu,Hokkaido, Japan, 3Health Sciences University of Hokkaido, Sapporo, Japan Objectives: The purpose of this study was to elucidate the influence of clenching on head posture and body sway. Methods: In 5 healthy, fully dentate males, the impact load (10.29 J) disturbing the body balance to the shoulder was applied to each subject standing upright on a stabilometer under the eyes closed condition. The head movement and body sway were recorded by the electromagnetic, six-degree-of-freedom tracking instrument and the stabilometer. The electromyographic (EMG) activity of masseter, sternocleidomastoid, rectus femoris, and tibialis anterior muscles were recorded simultaneously. The head movement, body sway and EMG activity were recorded at the intercuspal position with 25%, 50%, 75% and 100% of the voluntary maximal clenching (VMC) and the mandibular rest position (RP) during the impact load. All data from the above were analyzed. Each VMC condition was controlled by using the audio feedback system with the masseter muscles. Statistical analysis was performed by SPSS . Results: For the head movement, total locus length in RP was statistically greater than that in 25%, 50%, 75% and 100%VMC (p<0.05). For the body sway, total locus length in RP was statistically greater than that in 25%, 50%, and 75%VMC (p<0.05). For the EMG activity, the sternocleidomastoid muscle activities statistically grew according to the increase of the clenching level. On the other hand, EMG activities of rectus femoris and tibialis anterior muscles were not affected by the clenching level. Though the rectus femoris muscles and tibialis anterior muscles activities were concerned in correcting body sway, the relationship between their EMG activities and body sway were not recognized. From the study, it is suggested that teeth clenching may play an important role in the head movement and body sway during the impact load. Conclusions: It is speculated that there is an interdependent relationship between stomatognathic function and body equilibrium. | ||
| Seq #197 - Masticatory Performance and Oral Function 10:15 AM-11:30 AM, Friday, 12 March 2004 Hawaii Convention Center Exhibit Hall 1-2 | ||
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