The Journal of Japanese Society of Stomatognathic Function
Online ISSN : 1883-986X
Print ISSN : 1340-9085
ISSN-L : 1340-9085
Volume 13, Issue 1
Displaying 1-15 of 15 articles from this issue
  • Youichi Yamasaki
    2006 Volume 13 Issue 1 Pages 1
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Noriaki Yoshida
    2006 Volume 13 Issue 1 Pages 2-10
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    It has been suggested that experiences of chewing various kinds of food with different consistency contribute significantly to the development of the human masticatory function. Nevertheless, the modern human diet consists more and more of thoroughly processed and cooked foods, which dramatically reduce the demand on the stomatognathic system. The consequences of such a change in alimentary habits are not fully understood. In this study we used three-dimensional jaw-movement tracking device and jaw-muscle electromyography (EMG) to analyze changes in masticatory function in mice fed liquid or solid diets after weaning, and the hypothesis that the daily diet of soft food prevents the development of masticatory function was examined. As a result, we found that 1) The capacity to discriminate consistency of food is reduced in mice raised on liquid diet. 2) Patterns of jaw movement trajectories and masticatory rhythm were extremely unstable in liquid diet mice. 3) Either the masticatory central pattern generator (CPG) or its peripheral feedback mechanisms may be underdeveloped in animals raised on soft foodstuffs, although the conversion from sucking to chewing is not prevented.
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  • Yasuo Tamura
    2006 Volume 13 Issue 1 Pages 11-15
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    In order to evaluate the development of masticatory function in children, we have observed the accuracy of jaw movements, the silent period, the muscle fiber conduction velocity (MFCV) and the maximum bite force (MBF) from children to adults.
    1. Accuracy of the jaw movement rhythm was significantly inferior in children to that of adults; however the accuracy was improved with age.
    2. The duration of the silent period (SPD) during tooth tapping was significantly longer about 2 ms in children than in adults in both temporal and masseter muscles. In addition, SPD in the masseter muscle was observed by applying chin tap stimulation during both clenching teeth (10%, 50%, and the maximum) and biting on a transducer (50N, 100N and the maximum) . When comparing SPDs between children and adults at the same voluntary efforts, the children exhibited significantly longer SPD than that of adults. The results suggest that SPD was positively influenced by the strength of the background activities of the muscles and that immaturity of the masseter in terms of muscle activity could affect the SPD.
    3. The muscle fiber conduction velocity (MFCV) of the masseter muscle in children was significantly slower than adults, whereas the biceps muscle of upper arm was not changed due to development. Change of MFCV may be due to the differences of proportion of the muscle fiber types such as fast twitch and slow twitch fiber with development.
    4. Though the maximum bite force (MBF) showed an increase with age, it was more enhanced during the late mixed and permanent dentition. As the MBF increased, the speed for MBF also accelerated, hence the momentary bite force of the masticatory muscle increased with age.
    From these results, the children were demonstrated that their masticatory function was inferior in terms of not only the power of masticatory muscles but also the accuracy of the jaw motion to that of adults, and was developed with age.
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  • —New gastroenterological approach—
    Shouichi Miyawaki
    2006 Volume 13 Issue 1 Pages 16-20
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    Sleep bruxism frequently observed in children is defined as a stereotyped movement disorder characterized by tooth grinding and clenching during sleep. It often causes abnormal tooth wear, fracture, hypersensitivity, masticatory muscle discomfort, pain and/or TMD. It has been considered to be a parafunction in dentistry and it has also been placed in the parasomnia section according to the International Classification of Sleep Disorders. Recently, we reported that swallowing and gastroesophageal reflux (GER) might be associated with sleep bruxism. In this review article, I describe the definition of bruxism along with its diagnostic criteria, pathophysiology, signs and symptoms, hypothesis for cause, associated factors including our new findings such as swallowing and GER.
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  • Yonezo Saito, Hidetoshi Hirano, Masayuki Kurose, Yoshiaki Yamada
    2006 Volume 13 Issue 1 Pages 21-30
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    There were little studies to measure cervical range of movement in Japan. In the present study, we applied an electrical goniometer for 27 of subjects to record the range of motion and movement trajectories of head inclination and turning tasks. In comparison of ranges with those of the previous studies, the range in pitch was found to be identical, however, that in roll was larger. The range was then analyzed for handedness, age and gender. In this study, no difference was found for handedness and gender; however, younger subjects showed significantly larger range in posterior, right and left directions. This suggests that range of motion in the anterior direction may be restricted by the morphological factor rather than muscles and/or soft tissues which could be affected with aging. Movement trajectories represented on the horizontal plane revealed movement instabilities in some of the asymptomatic subjects.
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  • Ayako Tokuda, Hitoshi Kato, Hiroyuki Miura, Daizo Okada, Koko Hoshino, ...
    2006 Volume 13 Issue 1 Pages 31-37
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
    This study investigated the relation between occlusal contacts and the main occluding area. The 18 unilateral posterior dental arches were examined. The subjects were instructed to bite a piece of dental stopping once freely where there was easy to bite. A trial was repeated five times. We confirmed the region, where biting of the stopping was concentrated, as the main occluding area. We examined the location of the main occluding area. We divided the subjects into two groups, that is, the group whose biting place of the stopping was corresponding in all of the five trials and the others. We compared the occlusal contacts and the difference of both groups was analyzed quantitatively and qualitatively. As a result, the following conclusions were obtained.
    1. The main occluding area was located between upper and lower first molars in many cases.
    2. The percentage of the contact area, which was located in the main occluding area, in the total occlusal contacts of the unilateral posterior teeth was 32.6% in the group whose biting place of the stopping was corresponding in all of the five trials. That of the other group was 16.3%.
    3. It was suggested that the location of the occlusal contact points, which conducted occlusal force in the direction of the tooth root and brought physiological tooth movement during function, was required conditions for the main occluding area.
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  • Chikako Tsurui, Yoshiaki Arai, Makoto Inoue, Hiroshige Taniguchi, Yosh ...
    2006 Volume 13 Issue 1 Pages 40-41
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Shinobu Hasegawa, Yoshihiro Nishida, Satoshi Yamada, Yasuo Tamura
    2006 Volume 13 Issue 1 Pages 42-43
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Takafumi Kato, Yuji Masuda, Toshifumi Morimoto
    2006 Volume 13 Issue 1 Pages 44-45
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Yuzuru Furuki, Koske Nozaki, Chiharu Shin, Yoshihiro Tanaka, Shigeo Ha ...
    2006 Volume 13 Issue 1 Pages 46-47
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Kazuhide Matsunaga, Noritaka Isogai, Kensyu Kawanishi, Shinichi Asamur ...
    2006 Volume 13 Issue 1 Pages 48-49
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Yuji Masuda, Takafumi Kato, Toshifumi Morimoto
    2006 Volume 13 Issue 1 Pages 50-51
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Kyoko Sanefuji, Masahiko Yamada, Tatsunori Sibasaki, Ichiro Okayasu, M ...
    2006 Volume 13 Issue 1 Pages 52-53
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Hiroshi Shiga, Yoshinori Kobayashi, Ichiro Arakawa, Masaoki Yokoyama, ...
    2006 Volume 13 Issue 1 Pages 54-55
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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  • Akihito Gotouda, Taihiko Yamaguchi, Kazuki Okada, Takamitsu Matsuki, S ...
    2006 Volume 13 Issue 1 Pages 56-57
    Published: October 30, 2006
    Released on J-STAGE: October 13, 2010
    JOURNAL FREE ACCESS
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