Ichiro Arakawa

The Nippon Dental University, Edo, Tokyo, Japan

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Publications (22)8.11 Total impact

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    I Arakawa · K Koide · M Takahashi · F Mizuhashi
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    ABSTRACT: The aim of this study was to investigate the effect of the tongue rotation exercise training on the oral functions using the measurement of maximum tongue pressure (MTP) and labial closure strength (LCS) in normal adults. In experiment 1, the differences in MTP and LCS at the measurement point for both groups with and without tongue rotation exercise training were examined. We instructed subjects to perform the tongue rotation exercise for 2 months. We measured MTP and LCS at the point before training and at the points of 1 and 2 months after the beginning of training. In experiment 2, the changes of MTP and LCS based on the sex differences and the measurement points in training were examined. We instructed subjects to perform the tongue rotation exercise for 3 months, and measured MTP and LCS at the point before training and at the points of 2 weeks and 1, 2 and 3 months after the beginning of training. The results of experiment 1 showed MTP and LCS increased with the progress of continuous training. The results of experiment 2 showed MTP and LCS were always higher in men than in women and increased significantly at 2 weeks of training in both sexes (P < 0.01). These results might be suggested that the tongue rotation exercise training was effective for the recovery of the activity of the stomatognathic system. © 2015 John Wiley & Sons Ltd.
    Full-text · Article · Jan 2015 · Journal of Oral Rehabilitation
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    M Takahashi · K Koide · I Arakawa · F Mizuhashi
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    ABSTRACT: The aim of this study was to determine the association between strength of the perioral muscles and masticatory performance. Subjects were 56 healthy adults (30 men and 26 women; mean age of 24·9 years) with normal occlusion. Perioral muscle pressure was measured using JMS tongue pressure measurement device, and maximum tongue pressure and cheek pressure on the habitual chewing side (H) and non-habitual side (non-H) were measured. The masticatory performance was evaluated using gummy jelly, and the amount of glucose extracted was measured after chewing under condition H or non-H. The association between sex and maximum tongue pressure was analysed using Student's t-test. Cheek pressure and the amount of the glucose extracted between condition H and non-H or between men and women were analysed by two-way repeated-measures anova. In addition, the correlations between maximum tongue pressure and cheek pressure on condition H, maximum tongue pressure and the amount of glucose extracted under condition H, and cheek pressure and the amount of glucose extracted under condition H were analysed using Pearson's correlation coefficients for men and women. The maximum tongue pressure, cheek pressure and the amount of glucose extracted were higher in men than in women. The amount of glucose extracted was higher under condition H than under condition non-H, but no significant difference in chewing side was observed in cheek pressure between men and women. Additionally, positive correlations were shown between maximum tongue pressure, habitual-side cheek pressure and the amount of glucose extracted on men and women. In conclusion, the association between higher perioral muscle pressure and better masticatory performance was shown.
    Full-text · Article · Oct 2013 · Journal of Oral Rehabilitation
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    ABSTRACT: To clarify whether there might be a gender difference in masticatory performance in dentate adults. Thirty male subjects and thirty female subjects were asked to chew gummy jelly on their habitual chewing side for 10, 15 and 20s and the amounts of glucose extraction were measured. The changes of both glucose extraction and standardized glucose extraction from 10 to 20s were investigated differently for males and females. The amount of glucose extraction was compared between males and females for each chewing duration. In addition, in order to confirm a gender difference in occlusal force, the maximum occlusal force was compared between males and females. For both males and females, the amount of glucose extraction was lowest for 10-s chewing and increased significantly for 15-s and 20-s chewing. The mean standardized glucose extraction values increased in proportion with the duration of chewing. The standard deviations of the standardized glucose extraction were very small (below 0.02) for all chewing durations in both males and females. With regard to comparison of the glucose extraction between males and females, the amount of glucose extraction was significantly larger for males than for females for all chewing durations. The maximum occlusal force was significantly larger for males. It was suggested that it might be important to take into consideration gender-related differences while analyzing masticatory performance in dentate adults.
    No preview · Article · May 2012
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    ABSTRACT: The purpose of this study was to clarify whether differences in masticating conditions affected masticatory path stabilities of healthy subjects and TMD patients. Twenty healthy female subjects as the healthy group, and 20 female Temporomandibular Disorders (TMD) patients as the TMD group, were selected. Incisal point movement of during mastication of both masticating condition 1 (mc1; crispy bread chewed until swallowing on the free side) and masticating condition 2 (mc2; softened chewing-gum chewed for 20s on the habitual side) were recorded by MKG. As for mc1, out of all cycles during mastication only those cycles on the habitual chewing side were analyzed. As for mc2, the ten cycles from the fifth cycle were analyzed. For these analyzed sections, the indicators representing movement path stability were calculated and compared between the two groups. As for mc1, though the values of the indicators representing path stability were larger for the TMD group, there were cases where no significant differences were found between the two groups. As for mc2, the values were significantly larger for the TMD group (SDs; P<0.05, SD/ODs; P<0.01). From these results, it was suggested that the differences in masticating conditions affected the assessment of masticatory path stabilities of healthy subjects and TMD patients and the conditions should be considered for analyzing masticatory movement.
    No preview · Article · Aug 2011
  • Y. KOBAYASHI · M. YOKOYAMA · H. SHIGA · I. ARAKAWA
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    ABSTRACT: Objectives: The purpose of this experiment was to investigate the usefulness of a bio-phenomena recording system that uses a simple and easy but high-precision portable amplifier that records the bio-phenomena of a person during sleep. Methods: Ten healthy healthy subjects and 10 bruxists in their twenties who has been explained of the purpose of the experiment were selected as subjects. Bio-phenomena of subjects during sleep, such as masseter muscle EMG, mental muscle EMG, EEG, ECG, and EOG were recorded using both a wireless telemeter system and a portable system. Analysis was performed on bio-phenomena obtained from wireless telemeter system and portable system on an arbitrarily selected section. Sleep stages, heart rate, duration of masseter muscular activity during bruxism and its cumulative value were calculated and compared between the two devices. Results: The values obtained of sleep stages, heart rate, duration of masseter muscular activity during bruxism and its cumulative value of the arbitrarily selected section were very similar for both devices, and no significant difference was found between the two devices (duration of masseter muscular activity. telemeter system: 12.18 msec, portable system: 12.11 msec, p>0.05, n.s.). Conclusions: From these results it was concluded that the bio-phenomena recording system using a portable amplifier has similar precision as the wireless telemeter system, and thus could be used clinically in analyzing sleep stages, heart rate, duration of masseter muscular activity during sleep bruxism and its cumulative value.
    No preview · Conference Paper · Jul 2010

  • No preview · Article · Jan 2010
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    ABSTRACT: The purpose of this study was to clarify whether there was a difference in the masticatory function between two masticatory path patterns: a convex closing path and a concave closing path. For 80 healthy subjects, the masticatory function (masticatory muscular activity, mandibular movement, and masticatory performance) when chewing a gummy jelly was recorded. Out of the 160 chewing cases (80 subjects chewing on either side), 65 cases (Group I) in which the incisal point opened in a linear or concave manner toward the working side and closed in a convex manner, and 15 cases (Group II) in which the opening path was the same as that in Group I, but the closing followed a concave path, were selected. For the masticatory function, the integral values per unit time of masseter and temporal muscular activities, the gape and masticatory width, the indicators representing the stability of movement path, and the glucose extraction from chewing gummy jelly were measured and compared between the two groups. The integral values of muscular activities and the amount of glucose extraction were significantly greater in Group I. The gape and masticatory width were not significantly different between the groups. The values of the indicators representing the stability of path were smaller in Group I than in Group II. From these results, it was suggested that there was a functional difference between Group I (with a convex closing path) and Group II (with a concave closing path), and that Group I had a superior masticatory function to Group II.
    No preview · Article · Aug 2009
  • H. SHIGA · Y. KOBAYASHI · I. ARAKAWA · M. YOKOYAMA
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    ABSTRACT: Objectives: The purpose of this experiment was to clarify the effect of the taste of food on the brain blood flow and masticatory movement. Methods: Ten healthy subjects in their twenties (5 males and 5 females, average age 25.6 years) were asked to chew three types of gummy jelly (regular, moderately bitter with 0.016% quinine, and bitter with 0.032% quinine) on their habitual side for 20 seconds. The masseter muscular activity and blood flow in the brain were recorded simultaneously using EMG and NIRS (Near-Infrared Spectroscopy). The measuring probe was placed on the skin over the cortical masticatory area. The number of cycles, integral value of masseter muscular activity and the amount of change in the blood flow during the first half of chewing and the latter half of chewing were calculated separately. The results were compared among the three types of foods. Results: During the first half of chewing, the number of cycles, integral value of the masseter muscular activity and the amount of change in the blood flow were not significantly different among the foods. During the latter half of chewing, although the integral value was not significantly different among the foods (regular: 27.0mVmsec, moderate bitter: 27.2mVmsec, bitter: 27.7mVmsec, F=0.270, p>0.05, n.s.), the number of cycles and amount of change in the blood flow were the smallest during chewing of the bitter gummy jelly and largest during chewing of the regular gummy jelly, thus, significant differences were found among the foods (number of cycles: F=9.239, p<0.05, s, amount of change in the blood flow: F=23.899, p<0.05, s). Conclusions: From these results it was suggested that the taste of food affected the brain blood flow and the masticatory movement without changing the level of muscular activity.
    No preview · Conference Paper · Apr 2009
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    Full-text · Article · Apr 2009 · Journal of Prosthodontic Research
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    ABSTRACT: To clarify the masticatory path patterns of the mandibular incisal point during mastication of softened chewing gum with regard to gender difference. One hundred healthy subjects (50 males and 50 females) were asked to chew softened chewing gum on one side at a time (right side and left side) and the movement of the mandibular incisal point was recorded using MKG K6I. After a catalog of path patterns was made, the movement path was classified into one of the pattern groups, and then the frequency of each pattern was investigated. A catalog of path patterns consisting of the three types of opening path (op1, linear or concave path; op2, path toward the chewing side after toward the non-working side; op3, convex path) and two types of closing path (cl1, convex path; cl2, concave path) was made. The movement path was classified into one of seven patterns, with six patterns being from the catalog and a final extra pattern in which the opening and closing paths crossed. The most common pattern among the subjects was Pattern I, followed by Patterns III, II, IV, V, VII, and VI, in that order. The majority of cases, 149 (74.5%) of 200 cases, showed either Pattern I (op1 and cl1) or Pattern III (op2 and cl1). There was no significant difference between the two genders in the frequency of each pattern. The movement path could be classified into seven patterns and no gender-related difference was found in the frequency of each pattern.
    No preview · Article · Feb 2009
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    ABSTRACT: To clarify the usefulness of the standard deviation (SD) and SD divided by the opening distance (SD/OD) of the opening lateral, closing lateral, and vertical components of the masticatory path as indicators of the stability of masticatory movement path. Fifty subjects masticated softened chewing gum on the unilateral side for 20s, and the movement of the mandibular incisal point was recorded. For 10 cycles from the 5th cycle of 100 cases (50 subjects chewing on either side), a picture comprising each cycle path was displayed and classified subjectively into three categories (stable, unstable, and unknown) by three evaluators. The 18, 17, and 19 cases that were assessed as stable, unknown, and unstable were classified as Groups A, B, and C, respectively. For 10 cycles from the 5th cycle, the SD and SD/OD of the opening lateral, closing lateral, and vertical components representing the movement path as indicators for the stability of the path were calculated and compared among the three groups. The SD and SD/OD of the opening lateral, closing lateral, and vertical components were small in Group A, increased in Group B, and increased further in Group C. Significant differences were observed among the groups. These differences were more apparent in the assessment using the SD/OD than in the assessment using the SD. The SD and SD/OD of the components representing the movement path were useful as indicators for the stability of the movement path and the SD/OD appeared to be particularly useful.
    No preview · Article · Feb 2009
  • H Shiga · Y Kobayashi · I Arakawa · M Yokoyama · A Tanaka
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    ABSTRACT: The purpose of this study is to clarify whether the state of occlusal contact on lateral excursion is related to the pattern of masticatory movement path. The masticatory movement during mastication of softened chewing gum and the occlusal contact on lateral sliding of the mandible by 1 mm (L1), 2 mm (L2) and 3 mm (L3) were recorded in 50 healthy subjects. The path of masticatory movement was classified into one of seven patterns. The number of teeth involved in the occlusal contact in each pattern was investigated and compared among different lateral occlusal positions. The occlusal contact was then classified into 15 types based on one or a combination of the following four regions; incisal region, canine region, premolar region and molar region. The number of occlusal contact type for each pattern was investigated and compared among patterns. The number of teeth involved in occlusal contact decreased as the degree of lateral excursion increased, and significant differences were observed among the lateral occlusal positions (P < 0.001). The occlusal contact tended to decrease in the molar region and increase in the canine or premolar regions as the degree of the lateral excursion increased. When comparing among patterns, significant differences were observed at L2 and L3 (L2; P < 0.001, L3; P = 0.030) but not at L1 (P = 0.318). The difference was remarkable at L2. It was suggested that the state of occlusal contact at L2 and L3, particularly at L2 was related to the masticatory path pattern.
    No preview · Article · Feb 2009 · Journal of Oral Rehabilitation

  • No preview · Article · Jan 2008 · Prosthodontic Research & Practice

  • No preview · Article · Jan 2007 · Prosthodontic Research & Practice
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    ABSTRACT: Purpose: The purpose of this experiment was to investigate the possibility of objectively evaluating masticatory performance using a portable blood glucose testing device.Methods: First, the glucose concentrations of four types of glucose solutions with known concentrations were measured using a spectrophotometer and portable blood glucose testing device. Next, 20 healthy subjects were asked to chew gummy-jelly for 20 seconds and the amount of glucose extraction was measured. The results for the two devices were compared.Results: The glucose concentration according to the spectrophotometer was very close to the true concentration. On the other hand, the glucose concentration according to the blood glucose testing device was not close to the true value, although a statistically significant linearity was found. In regard to measurement of the amount of glucose extraction, there was a significant difference between the results obtained with the two devices. However, by using a regression line and applying the corrections to the values obtained, the values of the blood glucose testing device could be brought close to the values of the spectrophotometer (y=1.036x−2.491, r=0.994, P<0.01).Conclusion: From these results, it was concluded that, after applying correction, a portable blood glucose testing device could measure the amount of glucose extraction from chewing gummy-jelly as accurately as a spectrophotometer.
    No preview · Article · Jan 2006 · Prosthodontic Research & Practice

  • No preview · Article · Jan 2006 · Prosthodontic Research & Practice

  • No preview · Article · Jan 2005
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    ABSTRACT: 目的: 咀嚼運動や他の身体運動がそれぞれ脳内血流に及ぼす影響を明らかにする目的で, 近赤外分光装置 (NIRO300) による脳内血流分析システムを開発した。方法: 健常男性3名 (26歳, 32歳, 36歳) に咀嚼運動, 指タッピング運動, 動的掌握運動をそれぞれ30秒間行わせた時の咬筋筋活動をEMG, 脳内血流を近赤外分光装置で同時記録後, 咬筋筋活動と脳内血流の変化を検索できるようにプログラムを作成した。なお, 脳内血流の測定プローブは, 照射部と受光部の距離を4cmとし, 運動野相当部の皮膚上に毛髪をかき分けて, 開閉口運動と指の運動とに最も反応する位置に設定した。実験終了後, プローブの設定位置を確認するため, 照射部と受光部の中間の位置の皮膚上にプラスチックカプセルを置き, MRIの撮影を行った。結果: MRI画像から, 照射部と受光部の中間の位置が運動野相当部の皮膚上に設定されていることが確認できた。いずれの被験者においても咬筋筋活動と脳内血流の変化を経時的に記録, 観察することができた。脳内血流は, いずれの運動時でも増加したが, その増加量は, 咀嚼運動が最も大きく, 以下指タッピング運動, 動的掌握運動の順に小さくなる傾向を示した。また, この脳内血流の増加を定量的に表示することができた。結論: 本研究で開発した脳内血流分析システムは, 咀嚼運動や他の身体運動における脳内血流の変化を視覚的, 定量的に評価できることが示唆された。
    No preview · Article · Jan 2004
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    ABSTRACT: In order to find the most suitable food and chewing side for evaluating the stability of masticatory movement, three types of food with varying textures, as well as both free chewing and unilateral chewing, were utilized in analyzing the masticatory path during mastication. A piece of chewing gum, one peanut, and a slice of crispy bread were used as test foods. For 20 healthy subjects, movement of the incisal point while masticating a test food for 10 s on the free side and the habitual side was recorded. Indicators representing movement path stability were calculated and compared among the foods and between the chewing sides. Masticatory movement was most stable when masticating chewing gum, and less stable for the peanut, and most unstable for the crispy bread. There was a statistically significant difference between each pair of foods for almost all of the indicators. The indicators for peanut were approximately 1.5 times larger than those for masticating chewing gum and the indicators for crispy bread were double those for the chewing gum. When comparing free chewing with unilateral chewing, the masticatory movement of unilateral chewing was significantly more stable than that of free chewing for all test foods. From these results it was suggested that, for evaluating masticatory movement path stability, the most suitable type of food was softened chewing gum and the most suitable chewing method was unilateral chewing on the habitual chewing side.
    No preview · Article · Oct 2003 · Odontology
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    ABSTRACT: デンタルプレスケールシステムで表示される咬合力の信頼性を検証する目的で, デンタルプレスケールに異なる5種類の荷重圧を加え, デンタルプレスケールの発色状態とデンタルプレスケールシステムで表示される咬合力について分析した.実験は, 1辺が1mmの正方形で1mm2の面をもつ直方体の加圧子 (加圧子A) と面積が1mm2の円柱状の加圧子 (加圧子B) を較正用圧力装置に装着後, デンタルプレスケール (50H・R type) に20, 40, 60, 80, 100Nの5種類の荷重をそれぞれ加えた.分析は, はじめに各荷重時のデンタルプレスケールの発色状態を観察後, 加圧子Aと加圧子Bの発色面積を算出し, 各荷重間で比較した.次いで, オクルーザー (FPD703, 富士写真フイルム) を用いて, デンタルプレスケール上に記録された咬合力を測定後, 加圧子Aと加圧子Bについて, 荷重圧と咬合力との間で相関の有無を調べた.また, 加圧子Aと加圧子Bにおける各荷重圧の咬合力について, 加圧子間で比較した.20~100Nの各荷重時のデンタルプレスケールの発色状態は, 加圧子の形状を示し, その面積は, いずれも1mm2に近似し, 荷重間に差が認められなかった (F=1.306, p>0.05) .デンタルプレスケールシステムで表示される咬合力は, 加圧子Aと加圧子Bともに, 荷重圧が増すに従って増大し, 荷重圧と咬合力との間にそれぞれ有意な正の相関が認められた (加圧子A; r=0.991, p<0.01, 加圧子B; r=0.990, p<0.01) .加圧子Aと加圧子Bにおけるデンタルプレスケールシステムで表示される咬合力は, いずれの荷重時でも, 加圧子Aと加圧子Bの値が近似し, 両者間に有意差が認められなかった.また, デンタルプレスケールシステムで表示される咬合力は, 加圧子A, 加圧子Bともに, 20~80N荷重では, ほぼ理論値に近似したが, 100N荷重では, 理論値よりも小さかった.これらの結果から, デンタルプレスケールシステムは, 20~80N荷重では, 強さに応じた咬合力を正確に測定できるが, 100N荷重では, 正確に測定できないことが確認された.
    No preview · Article · Jan 2003