Journal of Osaka Dental University
Online ISSN : 2189-6488
Print ISSN : 0475-2058
ISSN-L : 0475-2058
Volume 46 , Issue 1
Showing 1-23 articles out of 23 articles from the selected issue
  • Seiji Kano, Yoshiko Matsuda, Junihciro Kotani
    Type: Article
    2012 Volume 46 Issue 1 Pages 1-4
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Modafinil, a drug for the treatment of hypersomnia and narcolepsy, activates dopaminergic neurons and histaminergic neurons and inhibits the release of gamma-aminobutyric acid to enhance awakening from natural sleep. However, it is unclear whether modafinil modulates the hypnotic effects of volatile anesthetics. We therefore investigated the effects of intravenous modafinil on the depth of anesthesia in rats under sevoflurane anesthesia by evaluating the spectral edge frequency 95% (SEF95) of the electroencephalogram. Modafinil at various doses did not induce changes in SEF95 in animals anesthetized with a fixed concentration of sevoflurane. The absence of inhibition of the hypnotic effect of sevoflurane suggests that modafinil targets areas in the brain that are not involved in awakening from natural sleep.
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  • Yi-ru Fang, Fumihiko Suwa, Mamoru Uemura, Masahiro Wato, Akio Tanaka
    Type: Article
    2012 Volume 46 Issue 1 Pages 5-9
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Since 2008, we have performed acupuncture on students at Osaka Dental University during their lunch breaks after listening to their questions and concerns. Beauty concerns for female students in particular included rough, dull or dry skin together with acne, red spots, wrinkles, dark under-eye circles, puffiness and hyper pigmentation. By 2011 we had treated 40 female students. Acupuncture methods included promoting Qi circulation as a fundamental treatment and cosmetic acupuncture to treat symptoms. The acupoints used to improve Qi circulation were Baihui, Quchi, Neiguan, Hegu, Zusanli, Sanyinjiao and Taichong. For cosmetic acupuncture, we inserted needles into the following acupoints on the face: Shangxing, Yintang, Touwei, Yangbai, Sizhukong, Taiyao, Chengqi, Xiaguan, Yingxiang, Dicang and the superior border of the clavicle (in a necklace configuration). The flow of Qi was improved with a protocol designed to promote Qi circulation. Cosmetic acupuncture was performed after confirming that changes in the student's physical condition and facial appearance improved with cosmetic acupuncture.
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  • Saeko Sumikura, Hiroshi Inoue, Yasuo Nishikawa, Naoyuki Matsumoto
    Type: Article
    2012 Volume 46 Issue 1 Pages 11-20
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Orthodontic tooth movement requires alterations in bone remodeling patterns in the alveolar bone underlying the tooth targeted for movement. Interleukin-17 A (IL-17) is a proinflammatory cytokine that is mainly secreted by activated T cells. The direct effects of IL-17 on the differentiation of osteoclast precursors into osteoclasts and on the function of osteoclasts remains unknown. We investigated the effects of IL-17 on osteoclast differentiation using RAW264 cells as osteoclast precursors. We tested the effect of IL-17 on the proliferation and differentiation of RAW264 cells, and on the expression of IL-17 receptors. Expression of IL-17 RC was confirmed on RAW264 cells by FACS analysis. IL-17 did not affect the proliferation, but suppressed the differentiation of RAW264 cells in the presence of soluble RANKL into osteoclasts in a dose-dependent manner. Phosphorylation of p38 MAP kinase was further enhanced in the presence of RANKL compared with the control, which was reduced by IL-17 in a dose-dependent manner.
    These results suggest that RANKL-induced osteoclast differentiation is suppressed by IL-17. Furthermore, it is suggested that inhibition of p38 MAP kinase phosphorylation by IL-17 may be one of the factors that suppresses the differentiation of osteoclast precursors into osteoclasts.
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  • Yuhei Nishida, Takashi Doi, Koji Kawasaki, Masaki Kambara
    Type: Article
    2012 Volume 46 Issue 1 Pages 21-35
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Mouthwashes have become widely used in the home. We investigated their effect on the process of incipient caries formation in vitro. Five commercial mouthwash products (four with fluoride and one without), two fluoride dentifrices, three aqueous sodium fluoride solutions at 150, 300, and 600 ppm, respectively, and distilled water were used. Blocks of enamel, 5mm×5mm, were cut from the labial surface of bovine teeth. After polishing, 3mm×3mm windows were made on the surfaces of the enamel samples using nail varnish. Each enamel sample was immersed in a demineralization solution of CaNO3, KH2PO4 and CH3COOH at pH 4.6 for 6 hours, then in either a mouthwash or dentifrice solution for 1 minute followed by remineralization in a solution of CaNO3, KH2PO4, KCl and NaC2H6 AsO2 at pH 7.0 for 18 hours. The samples were then placed in either a mouthwash or dentifrice solution for 1 minute. This procedure was repeated for 5 days, followed by treatment with the remineralization solution for 2 days using the pH cycling method to prepare incipient carious lesions. Digital images of the sample surfaces were acquired employing the quantitative light-induced fluorescence (QLF) method, and three analytical parameters : ΔF, area and ΔQ, were measured using accessory analytical software. The sample surfaces with incipient enamel caries were also observed under SEM.
    Fluoride mouthwashes significantly inhibited enamel demineralization compared with the non-fluoride group. No significant differences were noted in the parameters of QLF image analysis between the samples treated with fluoride dentifrices and fluoride mouthwashes. The fluoride level in the mouthwashes and dentifrices were significantly correlated with ΔQ, showing that demineralization was inhibited in a manner dependent on the fluoride concentration in the mouthwashes. The SEM images showed crystal structures formed around enamel prisms in the fluoride group. The density of the crystal structure increased as the fluoride level rose, and the production of a calcium fluoride-like substance was also noted. We found that mouthwashes inhibited the incipient caries formation process by remineralization of the enamel through the incorporated fluoride. It was also suggested that mouthwashes and dentifrices with a fluoride level greater than 200ppm effectively inhibit demineralization and subsequent incipient caries formation.
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  • Koichiro Jin, Masaki Kambara
    Type: Article
    2012 Volume 46 Issue 1 Pages 37-45
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    According to the National Survey of Dental Diseases of the Japanese Ministry of Health, Labour and Welfare, the decayed/missing/filled teeth (DMFT) index of 12-year-old Japanese children has shown a downward tendency since it peaked at 5.62 in 1975. However, this low rate of caries in 12-year-old children may indicate how the methods of the analysis may have changed. Using a birth-year cohort, we analyzed changes in the rate of dental caries in junior and senior high school students based on the above survey and examined the factors that affect the caries rate of these students, paying attention to lifestyle factors peculiar to this age group.
    Regression analysis showed that the DMFT index of junior and senior high school students is decreasing. Conversely, birth-year cohort analysis showed that this trend might not be a true reflection of the caries rate in students of this age. Moreover, in studying the lifestyle factors peculiar to junior and senior high school students, we found that 18-year-old males brushed their teeth fewer times each day and skipped breakfast more often compared with 12-year-old students and with students of all other ages.
    These results suggest that junior and senior high school students do not demonstrate healthy living behavior at a time when these habits should have already been established. To prevent future increases in dental caries among these students, environmental factors and lifestyle factors peculiar to them must be clarified. Because oral healthcare is important, it is necessary to conduct a lifestyle analysis based on objective oral health parameters such as the frequency and duration of toothbrushing.
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  • Yumi Sonoda, Kenji Uhcihashi, Yasuo Nishikawa, Naoyuki Matsumoto
    Type: Article
    2012 Volume 46 Issue 1 Pages 47-56
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We examined the effects of stress induced by orthodontic force in rats on the submandibular salivary α-amylase, lactoferrin and corticosterone levels, and compared the characteristics of these parameters. Male Wistar rats weighing 280-320 g were used. Salivary α-amylase, lactoferrin and corticosterone levels were measured at various times following lower incisor separation. Although both the α-amylase and lactoferrin levels significantly increased after lateral force activation, the corticosterone level did not. The carry-over effect was observed in both α-amylase and lactoferrin responses, but not in corticosterone. Salivary α-amylase and lactoferrin levels reacted rapidly after addition of orthodontic force. These results suggested that salivary α-amylase and lactoferrin are good indexes of orthodontic stress.
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  • Takashi Okamoto, Hironori Akiyama, Shoko Gamoh, Kimishige Shimizutani
    Type: Article
    2012 Volume 46 Issue 1 Pages 57-62
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    High-dose-rate interstitial brachytherapy (HDR-ISBT) is effective as a radical treatment for tongue cancer. The biggest issue regarding this treatment is, however, to reduce late complications that occur from six months after the treatment. In this study, the association between various patient factors and the occurrence of late complications was evaluated. The relationship between the total dose and local control rate was also determined. We found that the Brinkman index, which shows the smoking history, was higher in those who developed late complications than those who did not. No significant differences were seen in the other factors among the groups. There were no significant associations between the total dose and local control rate. Therefore, based on this study that demonstrated no differences in the local control rate regardless of the total dose, it was suggested that irradiation at a dose of 54 Gy is recommended to minimize the burden on the patients.
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  • Kenji Arita
    Type: Article
    2012 Volume 46 Issue 1 Pages 63-70
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    I evaluated the clinical outcome of short-term myofunctional therapy using an activator without any fixation for condylar fractures in children. This study included eight children, aged 2.8-14.6 (mean 7.5) years, with unilateral or bilateral fractured mandibular condylar processes. All patients underwent myofunctional therapy using a customized activator for 3-5 weeks without surgery, intermaxillary fixation, and functional exercises at Pediatric Dental Clinic of Tokushima University Hospital. Follow-up ranged from 1.0 to 6.9 (mean 3.8) years after treatment. The patients were assessed clinically, radiographically, and with computed tomography pre- and post-treatment. In addition, pre- and post-treatment measurements of maximal opening capacity were analyzed statistically. Evaluation after treatment showed that all patients achieved normal facial symmetry, occlusion, jaw mobility, and maximal mouth opening. However, one patient who was 14.6 years old had deviation on mouth opening. Maximal opening capacity was significantly greater from 6 months post-treatment (mean 51.1 mm) than at pretreatment (mean 22.7 mm ; p<0.01) or at the time of activator removal (mean 38.1 mm ; p<0.05). Bone remodeling and formation of a new condylar head were seen on computed tomography. The short-term use (3-5 weeks) of the removable activator is effective in the management of pediatric condylar fractures.
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  • Yoshihide Ugaki, Yuichi Onhishi, Kenji Kakudo
    Type: Article
    2012 Volume 46 Issue 1 Pages 71-77
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Early detection of precancerous and early cancerous lesions could greatly reduce both mortality and morbidity of oral cancer. The objective of this study was to analyze a fluorescence visualization (FV) system for the detection of precancerous and early cancerous lesions in rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide. Under direct FV, the normal oral mucosa emits various shades of pale green autofluorescence. In precancerous and early cancerous lesions, the lesion appears as an irregular, dark area. Histological examination of the lesions showed that the FV system (VELscope^[○!R]) has a sensitivity of 95% and specificity of 100% in discriminating normal mucosa from dysplasia/carcinoma in situ (Cis) or invasive carcinoma. The proliferating cell nuclear antigen (PCNA) protein gradually increased with progression of carcinogenic transformation. Furthermore, the result of PCNA and FV loss was correlated. These preliminary results suggest that this direct FV device has potential for simple, cost-effective screening and margin determination of oral precancerous and early cancerous lesions.
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  • Akiko Ohashi, Tatsuro Miyake, Masaki Kambara
    Type: Article
    2012 Volume 46 Issue 1 Pages 79-89
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Recently, interests in health and oral health have been increasing both individuals and society. We evaluated changes in the distance between ten reference points around the mouth during smiling to analyze the face. Twentyfive young Japanese adults (10 women, 15 men; Mean±S.D. 21.0±1.9) were participated. Digital facial images for 7 patterns (normal face, 4 types of smiles, and the pronunciation of "E" and "E-" sounds) were acquired using a digital camera. The distances between the points were measured using Photoshop CS4 (Adobe Systems, Japan). When the subjects were smiling, the distance between the labial commissures increased, and upper lip width and the distance between nasion and cheilion (Na-Ch) decreased compared with the normal face. However, the lower lip width and the distance between nasion and gonion (Na-Go) did not change. As the method to analyze the change of face, to measure the relative difference between reference points on the normal face and variation of smiles or the pronunciation of "E" using captured static photos was found be useful. These findings suggest that the upper lip, which is located near the greater zygomatic muscle, is affected more strongly than the lower lip by the action of this muscle. Based on these results, it was suggested that the patient pronouncing "E" may simulate an attractive smile.
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  • Kazuki Ogiso, Takayuki Nambu, Yoshio Kotsu, Hisanori Fukushima, Masato ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 91-99
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Although oral biofilms play an important role in chronic bacterial infections including periodontitis, the genetic mechanisms contributing to their development are poorly understood. To unravel the nature of the oral biofilm, we tried to identify genes responsible for biofilm formation in Actinomyces, which forms an adhesive platform to promote further attachment of the late colonizers of the oral biofilm. Using a random mutagenesis and biofilm assay for A. oris MG-1, a reference strain of Actinomyces isolated from a patient with gingivitis, we tentatively identified a mutant, AOM0010, with reduced biofilm phenotype. However, from the observations of growth rates, we conclude that AOM0010 is not so much the biofilm-defective mutant but the mutant with defects in growth. The transposon in AOM0010 was inserted into the ANA2550 encoding 2-C-methyl-D-erythritol 4-phosphate (MEP) cytidylyltransferase, suggesting that the function of this gene is required for cell growth in A. oris. Unfortunately, this study could not enhance our understanding of Actinomyces biofilm formation, whereas the strategy of transposon mutagenesis was applicable to A. oris MG-1. Therefore, further isolation and characterization of Tn 5 insertion mutants of A. oris MG-1 would lead to better understanding of molecular mechanisms underlying oral biofilm development.
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  • Norio Mukai, Junko Tanaka, Masahiro Tanaka, Takayoshi Kawazoe
    Type: Article
    2012 Volume 46 Issue 1 Pages 101-111
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We attempted to elucidate the pathogeneses in patients with uncomfortable occlusion. To set the reference ranges for the periodontal mechanosensitive thresholds (PMT), we selected 40 subjects (26 males and 14 females) with a mean age of 25±3 years who had normal occlusal contact in the intercuspal position (ICP). They were examined using the add-picture method and, measurement of the PMT was performed using von Frey's hairs. The reference ranges for the PMT were calculated by parametric methods. Next, we selected six subjects (2 males and 4 females) with a mean age of 43+11 years who complained of discomfort during occlusion. Occlusal contacts in the ICP were observed by the add-picture method. The PMT was measured in the aforementioned manner. The measurement of static and moving two-point discrimination thresholds (s-2 PD and m-2 PD, respectively) and the Semmes-Weinstein monofilament test were performed using a 2-PD discriminator and von Frey's hairs, respectively. The measurement sites were the regions served by the trigeminal nerve. .
    None of the subjects with uncomfortable occlusion had simultaneous bilateral equal molar contact. One patient had deviations in both the maxilla and mandible (Group A), another patient had deviations only in the maxilla (Group B), and the remaining four patients had no deviations from the reference ranges (Group C). Moreover, the subject in Group A had significant deviations from the reference ranges in all trigeminal nerve regions. These results suggest that some patients with uncomfortable occlusion have perceptual problems.
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  • Yukihisa Kokuba, Keiji Okuda, Teruta Maeda, Joji Okazaki
    Type: Article
    2012 Volume 46 Issue 1 Pages 113-120
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Sensory inputs from the periodontal membrane play a role in brain activation and regulate various functions or reflexive feedback. We investigated the possibility of a correlation between striatal function and loss of occlusal support. Eighteen male Sprague-Dawley rats were divided into three groups : the EXT Group (n=6) had all three maxillary molars on both sides extracted ; the EXT-R Group (n=6) had the right maxillary molars extracted ; and the CON Group (n=6) served as a control. Dopamine levels in the bilateral striatum were measured using in vivo microdialysis. Once the extracellular basal concentrations of dopamine were stable, the rats were fed pellets and the food-induced changes in dopamine concentrations were monitored every 10 min for 2 h. In the CON group, feeding induced a significant increase in dopamine concentrations on both sides of the striatum. However in the EXT and EXT-R Groups, no significant increase was observed. This result indicated that even if rats lost occlusal support unilaterally, food-induced dopamine release was impaired bilaterally in the dorsal striatum, and this impairment was associated with occlusal support loss that affected the contralateral striatum.
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  • Hiromasa Nakamura, Hiroshi Nishizaki, Joji Okazaki
    Type: Article
    2012 Volume 46 Issue 1 Pages 121-125
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    In recent years, the number of diabetes mellitus patients in Japan has been increasing in all age groups. Underlying factors are thought to include both the westernization of living habits and the aging of the population. Kusunoki et al. demonstrated that osteoporosis markedly inhibits osteogenesis in the tooth sockets in the ovariectomized rat model of osteoporosis. Conversely, Sakai et al. showed that type 2 diabetes does not markedly affect bone healing in 10-week-old type 2 diabetes model rats (GK rats). In the present study, we attempted to quantitatively clarify the effects of chronic hyperglycemia following diabetes onset on tooth socket bone healing.
    The experimental animals comprised male GK rats aged 10 weeks (n = 12) and 18 months (n = 12) and 24 age-matched male Wistar rats (control). Based on the methods used by Sato et al. and Sakai et al., the left mandibular incisor was extracted after pretreatment and a titanium alloy screw was immediately implanted into the tooth socket. At 3- and 9-weeks post-implantation, screw removal torque was measured using a hand-held torque gauge and the degree of socket healing was biomechanically and comparatively investigated.
    The results revealed a significant difference in bone healing for age and observation period (p<0.01) but not for the presence or absence of disease. A significant difference was also observed for the interaction between the factors of age and observation period (p<0.01). These findings suggest that although tooth socket bone healing was essentially unaffected by comparatively well controlled type 2 diabetes, it was strongly influenced by age. However, as age-related decrease in bone mass is alleviated by the accompanying decrease in bone turnover, there are reports of a greater increase in bone mass in elderly people compared to healthy adults. Further histological and biomechanical assessments as well as detailed investigation of bone vulnerability are required in addition to study on tooth socket bone mass and density.
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  • Makiko Furukawa, Hidetaka Ito, Teruta Maeda, Hiroshi Nishizaki, Joji O ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 127-135
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We produced experimental plates covering different areas of the palatal mucosa with different shapes, and attempted to evaluate them objectively by measuring stress reactions in terms of salivary amylase activity and secretory immunoglobulin A (slgA) concentration. All subjects were examined under the four experimental conditions of no plate (C), an anterior plate (A), a middle plate (M) and a posterior plate (P). Saliva samples were collected at 0, 5, 10 and 20 min after the start of each condition. Subjects were then asked to complete a Visual Analogue Scale (VAS) during each condition. Amylase activity of saliva collected at 5 min was significantly higher for P than for C, A or M. The VAS score was significantly higher for P than for A or M. However slgA concentration in saliva collected at 5 min was significantly lower for P than for C or M. Different patterns were seen for both amylase activity and VAS scores. Evaluation of amylase activity and the VAS of discomfort showed that covering the posterior region of the palate caused severe discomfort in the subjects. The use of salivary stress markers is a valuable tool for the objective evaluation of the design of maxillary partial dentures.
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  • Kazuya Takahashi, Kaori Tsujimoto, Tomomi Shibuya, Yutaka Komasa
    Type: Article
    2012 Volume 46 Issue 1 Pages 137-146
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Dysphagia is most often diagnosed using video fluorography, video endoscopy, and ultrasonography. Ultrasonography is superior for imaging soft tissue, and enables real-time evaluation of the dynamics of the tongue and pharyngeal region. Since tongue dynamics plays an important role in swallowing in the preparatory and oral stages, the oral cavity function has been evaluated by measuring tongue movement and morphology using the B or M mode of ultrasonography. Evaluation of oral cavity function in D mode using the Doppler method has also recently been reported. However, ultrasonography is not common compared to video fluorography and endoscopy because of a problem with the clarity of the test food images. In this study, we performed basic experiments to investigate appropriate test food for the observation of M-mode images and D-mode flow rate measurement. We also observed images of the oral cavity and measured the speed of food mass transport from the oral cavity to pharynx. Measurements were made using a Prosound SSD-5500 an ultrasonography system, and UST-9126 electronic convex sounding probe (both from Hitachi Aloka Medical, Tokyo, Japan). Five types of test food with different physical properties were prepared in 100cc portions : tap water, carbonated water, and tap water combined with 1, 2 or 3 g of thickener (Toromi Perfect^[○!R], Nisshin Oillio, Tokyo, Japan) (Toromi 1, 2 and 3, respectively). A silicon tube was horizontally fixed in deaerated water and adjusted so that the test food flowed in the tube. Test food flow in the tube was imaged using B-mode echo, and the image clarity was observed. In addition, the test food flow rate in the tube was measured employing the pulse Doppler method and compared with the measured rate calculated from piston movement of the opposite syringe. The subject's oral cavity while swallowing the test food was imaged using the B/D mode, and differences in the image clarity and oral-pharyngeal passage time among the test foods were investigated.
    With B-mode imaging thickened water was the most easily observed in the silicon tube. The flow rate spectrum was also clearly displayed in the D mode when the test food was thickened water. However, when the subjects were tested, many light spots were present in the thickened water and there was weakened contrast between the test food and surrounding tissue, making it difficult to observe tongue dynamics and confirm the test food flow. When carbonated water was swallowed, air bubbles were produced and imaged as light spots adhering to the dorsum of the tongue and palate. Echo images concentrated on these regions and made the flow of the test food and the tongue dynamics readily observable. The speed of oral-pharyngeal passage measured in the D mode was fastest for carbonated water, followed by tap water, and Toromi 1, 2 and 3, in that order.
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  • Kaori Tsujimoto, Kazuya Takahashi, Tomomi Shibuya, Yutaka Komasa
    Type: Article
    2012 Volume 46 Issue 1 Pages 147-156
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    In patients with feeding/swallowing disorders, adjustment of posture is a very effective means of preventing aspiration. A posteriorly flexed rather than vertical trunk position is widely known to be a safe body position in which aspiration is less likely to occur. Therefore, in patients at high risk of aspiration, the trunk and neck angles are adjusted clinically in various situations. Regarding the relationship between posture adjustment and swallowing dynamics, although there have been a number of evaluations in the pharyngeal and esophageal phases, few detailed evaluations have been made in the oral phase despite its importance. Physiologic evidence is considered to be insufficient in this area. In this study, the effects of posture adjustment on tongue dynamics in the oral phase were evaluated by measuring the tongue pressure on the palate using touch sensors.
    The subjects were 7 healthy dentulous individuals who had no feeding/swallowing disorder with a mean age of 26 years. The test food was water at 37 C. Swallowing volume was determined by having each subject swallow water 10 times consecutively and calculating the mean volume of a single gulp, which was found to be 7.9±1.4 mL. The test maneuver was a single gulp on instruction of the examiner. Swallowing was performed in a total of 6 body positions, i.e., at trunk angles of 90°, 60° and 30° relative to the floor, and with neck angles of neutral and anteriorly flexed/protruded positions at each trunk angle. Sensors were attached using the denture stabilizer Touch Correct II (Shionogi, Osaka, Japan) as follows: Sensor 1 was placed at the point of intersection between the line connecting the basal tubercles of the bilateral upper canine teeth and median line, Sensor 2 at the intersection between the line connecting the distal palatal cusps of the bilateral second upper molars and the median line, and the center of Sensor 3 immediately below the palatal neck of the left upper second molar on the line connecting the distal palatal cusps of the bilateral upper second molars.
    In the neutral neck position, all sensors indicated significant shortening of the duration of tongue pressure with increases in the angle of trunk flexion. In Sensors 1 and 3, the maximum tongue pressure decreased with increases in the angle of trunk flexion. In the anteriorly flexed/protruded neck position, no shortening of the duration of tongue pressure or decrease in the maximum tongue pressure associated with trunk flexion was noted. Changing the neck angle from the neutral to anteriorly flexed/protruded position seemed to compensate for the decrease in the maximum tongue pressure and the tongue pressure duration.
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  • Tomohiro Fujihira, Kazuyoshi Yamane, Masahiro Yoshida, Takayuki Nambu, ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 157-164
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Rothia mucilaginosa (R. mucilaginosa) strain DY-18 isolated from a persistent apical periodontitis lesion has dense meshwork-like structures around cells, which is typical for exopolysaccharide (EPS)-producing bacteria. In this study, to identify the genes responsible for EPS production in R. mucilaginosa, we isolated three meshwork-like structures defective mutants (strains FA1, FA7 and FA8) by random transposon mutagenesis using the Epicentre EZ-TN5 transposome system. EPS-producing ability was evaluated by measuring the viscosity of spent culture media. The viscosity of the spent culture medium obtained from strains FA1, FA7 and FA8 cultures was significantly lower than the strain DY-18 culture. The transposon insertion region of strain FA1 was determined by PCR direct sequencing analysis. The sequence of the insertion region was then compared with the published complete genome sequence of strain DY-18 on a database. Strain FA1 had a disruption in the RMDY 18_10020 gene encoding P-loop-containing kinase. This gene and downstream genes (RMDY 18_10030 and RMDY 18_10040) showed high homology to the genes yvcJ, yvcK and yvcL respectively. These genes are involved in competence and gene regulation in the stationary phase in Bacillus subtilis. These results suggest that the RMDY 18_10020 gene homologous to yvcJ is involved in EPS biosynthesis and thus plays an important role in biofilmformation of R. mucilaginosa.
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  • Kenzo Yasuno, Kohei Onda, Naohiro Iwata, Kazushi Yoshikawa, Kazuyo Yam ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 165-181
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We often use the Er: YAG laser for dental treatment as it has been shown to be excellent for preparing the hard tissues of teeth. However, it has been reported that the bond strength and marginal seal of composite restorations is adversely affected in dentin irradiated by the Er: YAG laser compared with non-irradiated dentin. We used the marginal leakage test and the shear bond test to evaluate the marginal seal of restorations placed in laser-irradiated cavities. The teeth were restored using the composite resin filling method with glass ionomer cement and flowable composite resin as lining materials.
    We found that the shear bond strength of conventional composite resin, flowable composite resin and low-shrinkage composite resin was significantly decreased for laser-irradiated dentin compared with that for conventionally prepared dentin, and that the bond strength of resin-modified glass ionomer cement to laser-irradiated dentin. Although the marginal seal of the laser-irradiated dentin wall was not improved when the dentin was lined with conventional glass ionomer cement and flowable composite resin or when it was filled by conventional methods, it was improved when lined with resin-modified glass ionomer cement or filled with low-shrinkage composite resin. Our results suggest that lining with resin-modified glass ionomer cement or the use of low-shrinkage composite resin improves the marginal seal of composite resin restorations placed in Er: YAG laser-irradiated cavities.
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  • Kensuke Nobata, Mamoru Uemua, Fumihiko Suwa, Naoyuki Matsumoto
    Type: Article
    2012 Volume 46 Issue 1 Pages 183-191
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    Temporary anchorage devices (TADs) are used to provide anchorage during orthodontic treatment. However, it has been reported that the microdamage (MD) that occurs during their insertion may cause dislodgement. No reports have investigated the sequential changes in MD resulting from the use of the TAD. We investigated the number of incidents and the length of MD occurring in the surrounding compact bone. Ten TADs were placed in each tibia of two beagle dogs used in this investigation. The four tibias were divided into the 4 groups of the 0, 1, 4 and 8 weeks after placement. Specimens were prepared for observation by light microscopy and scanning electron microscopy.
    The number of incidents of MD that occurred when TADs were placed did not increase over time. The length of the MD increased rapidly between 0 and 1 weeks after placement, increased slowly between 1 and 4 weeks, and then decreased slowly between 4 and 8 weeks. This suggests that orthodontic load should be applied no sooner than 8 weeks after placement.
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  • Misa Shimozuma, Takuji Iida, Naoyuki Matsumoto
    Type: Article
    2012 Volume 46 Issue 1 Pages 193-200
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We investigated changes in the activity of the lateral pterygoid muscle and in the position of the incisal point created by intermaxillary elastics during orthodontic treatment in ten males with a mean age of 26 years. All Subjects had normal occlusion with no signs or symptoms of temporomandibular disorder. The changes were recorded with and without intermaxillary elastics using the K7 evaluation system. We found that activities of the lateral pterygoid muscle increased with intermaxillary elastics when the mandible was at the rest position. These results suggest that the force of intermaxillary elastics can affect the activity of the lateral pterygoid muscle.
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  • Aki Nishiura, Keiko Sugino, Kenzo Oishi, Takashi Kuroda, Kazuhide Fuku ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 201-206
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    We report the morphological alveolar changes in 10 patients with unilateral cleft lip and palate after pre-surgical orthopedic treatment. Plaster casts of the maxilla made at the initial examination and just before cheiloplasty were measured and analyzed using a VIVID-910 three-dimensional laser scanner (Minolta Co., Tokyo, Japan). The pre-surgical orthopedic treatment was based on the method of Hirakawa et al. whereby a palatal plate is used prior to cheiloplasty. The palatal plates were placed for an average of 99 days.
    Use of the palatal plate reduced the alveolar cleft in all 10 cases. The major segment and minor segment cleft side stumps were moved toward the alveolar cleft, reducing the distance between the stumps (B-B') significantly. In addition, because the distance between the medial surfaces of both segments (C-C'1) was significantly reduced, it appeared that bone apposition was occurring toward the cleft palate site in the anterior region of the alveolar arch. The fact that the distance between the bilateral maxillary tuberosities (T-T') and the distance between the regions corresponding to the deciduous molar eruption (D-D') increased significantly suggests that the palatal plate did not inhibit growth in the maxillary alveolus.
    .The above suggests that pre-surgical orthopedic treatment using a palatal plate does not inhibit lateral growth in either segment. It also suggests that narrowing of the alveolar cleft width occurs by medially induced growth and that narrowing of the cleft alveolar site and cleft palate site are caused by medial bone apposition in the alveolar site.
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  • Emiko Nagaki, Aki Nishiura, Shoko Gamoh, Yoritaka Yotsui, Kimishige Sh ...
    Type: Article
    2012 Volume 46 Issue 1 Pages 207-213
    Published: 2012
    Released: January 05, 2017
    JOURNALS FREE ACCESS
    The muscular function of the jaw is concerned with maxillofacial growth and the development of the masticatory muscles. We divided the subjects into the two patterns, the Cant Group and the Rotation Group, based on the horizontal displacement of the mandible observed in postero-anterior cephalometric radiographs. The bone thickness and structure were evaluated by cone beam computed tomography (CT), and occlusal forces were measured with the Dental Prescale. Statistical differences between the two groups were found in the LOL' -ag line, lateral deviation (Shift) and cancellous bone width. In addition, a significant positive correlation was found between the pattern of mandibular deviation and the width of the cancellous mandibular alveolar bone. The results suggest that the pattern of mandibular deviation influences maxillofacial morphology, especially the gonion and lateral deviation (shift). The pattern of mandibular deviation related not only to masticatory function, but also to lower facial morphology.
    We concluded that the shape and structure of the mandibular alveolar bone are very important, not only for understanding its biomechanical significance associated with masticatory function, but also for understanding the occurrence of unfavorable sequelae resulting from orthodontic treatment.
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