J Jpn Prosthodont Soc, 35: 366 `380, 1991. The Influence of Craniofacial Form on Bite Force and EMG Activity of the Masticatory MusclesII. The Three-dimensional Bite Force Measurement Sytem Toshimitsu Iinuma, Nobuhito Gionhaku, Yoshihiko Moriya, Koji Takeuchi, Hideaki Takeuchi, Naoyuki Tsukakoshi, Yasunobu Orii, Kan Hasegawa, Akihiko Kanou, Yoshihisa Saitou, Shouichi Yamamoto and Katsuyuki Yamamoto Abstract: The purpose of this study was to explicate the mechanism of jaw movement and its control system, using bite force and EMG of the masticate muscles with a view to examine the result as an effective means of treatment. A new system of taking three-dimensional bite force was developed, which can take the value and direction of bite force. The description and evaluation of the new system and the result of the load test are presented. The results were as follows: 1. The vertical and lateral direction (60 degree on occlusal plane) load tests revealed that the precision of the three-dimensional bite force measurement system was fully established. 2. When using this system, it is necessary to use the jig for fixing the maxillary and mandibular clutches. 3. Using an oscilloscope as the bite force feedback device was useful to instruct the level of bite force. 4. This system is very effective to measure the value and direction of bite force. University School of Dentistry (Chief: Prof. Yoshihiko Moriya) Department of Complete Denture Prosthodontics, Nihon
Key words: three-dimensional bite force, value of bite force, direction of bite force, maxillary clutch, mandibular clutch
1) Maughan, R.J., Watson, J.S. and Weir, J.: Strength and cross-sectional area of human skeletal muscle, J Physiol, 338: 37-49, 1983. 2) Schantz, P., Randall-fox, E. and Hutchison, W. et al: Muscle fiber type distribution, muscle cross-sectional area and maximal voluntary strength in human, Acta Physiol Scand, 117: 219-226, 1983. 3) Maughan, R.J., Watson, J.S. and Weir, J.: Muscle strength and cross-sectional area in man: a comparison of strength trained and untrained subjects, Br J Sports Med, 18: 149 `157, 1984. 4) Weijs, W.A. and Hillen, B.: Cross-sectional areas and estimated intrinsic strength of the human jaw muscles, Acta Morphol Scand, 23: 267 `274, 1985. 5) Hagberg, C., Agerberg, G. and Hagberg, M.: Regression analysis of electromyographic activity of mastica- tory muscle versus bite force, Scand J Dent Res, 93: 396-402, 1985. 6) Haraldson, T., Carlsson, G.E., Dahlstrom, L. et al: Relationship between myoelectric activity in masticatory muscles and bite force, Scand J Dent Res, 93: 539 `545, 1985.
8) Mann, A., Miralles, R. and Palazzi, C.: EMG, bite force, and elongation of the masseter muscle under isometric voluntary contractions and variations of vertical dimension, J Prosthet Dent, 42: 674 `682, 1979. 9) Pruim, G.J., De Jongh, H.J. and Ten Bosch, J.J.: Forces acting on the mandible during bilateral static bite at different bite force levels, J Biomechanics, 13: 755 `763, 1980. 10) MacDonald, J.W.C. and Hannam, A.G.: Relationship between occlusal contact and jaw-closing muscle activity during tooth clenching part I, J Prosthet Dent, 52: 718 `729, 1984. 11) Belser, U.C. and Hannam, A.G.: The influence of altered working-side occlusion guidance on masticatory muscle and related jaw movement, J Prosthet Dent, 53: 406-413, 1985. 12) Gionhaku, N. and Hannam, A.G.: Lateral pterygoid muscle activity and anterior bite force, J Dent Res abstract, 66: 356, 1987. 13) Van Eijden, T.M.G.J., Koolstra, J.H. and Brugman, P.: A feedback method to determine the three-dimensional biteforce capabilities of the human masticatory system, 3 Dent Res, 67: 450-454, 1988. 25) Hosman, H. and Naeiji, M.: Reproducibility of the normalized electromyographic recordings of the masseter muscle by using the EMG recording during maximal clenching as a standard, J Oral Rehabil, 6 49 `54. 1979. 27) Osborn, J.W. and Baragar, F.A.: Bredicted pattern of human muscle activity during clenching derived from a computer assisted model: symmetric vertical bite forces, J Biomechanics, 18: 599-612, 1985.