Journal of Osaka Dental University
Online ISSN : 2189-6488
Print ISSN : 0475-2058
ISSN-L : 0475-2058
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Showing 1-12 articles out of 12 articles from the selected issue
  • Koichiro NAKAJIMA, Yoichiro TAGUCHI, Isao YAMAWAKI, Nobuhiro YAMAUCHI, ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 109-113
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    Antimicrobial photodynamic therapy has been used in clinics to minimize the susceptibility to bacterial resistance in patients with periodontal disease. It has been proven to be effective in treating bacterial, fungal, and viral infections. However, it is hard to ignore the effects of photosensitizers on the body. We investigated the effects of two typical photosensitizers, and assessed the proliferation of human gingival epithelial cells (HGECs) and the production of inflammatory cytokines after treatment with a high‐power, red light‐emitting diode (LED) along with photosensitizers. We found that methylene blue promotes proliferation of HGECs, whereas toluidine blue does not. The production of the inflammatory cytokines from HGECs decreases after LED irradiation. Hence, this study suggests that LED irradiation in the presence of either of the photosensitizers reduces inflammation in dental tissues such as the epithelium of periodontal pockets. (J Osaka Dent Univ 2019; 53: 109‐113)

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  • Kazuya MASUNO, Yoshitomo HONDA, Nobutaka OKUSA, Tetsunari NISHIKAWA, P ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 115-120
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We examined the effects of repetitive learning of English dental terms in a dental English course for second‐year students at Osaka Dental University. Using vocabulary levels as listed in the online Japanese‐English dictionary Weblio,1 we adopted six words listed as Level 1‐5, five words listed as Level 6‐10, three words listed as Level 11 or higher, and six words with no level listed. Students performed repetitive learning of each word in their dental English course at least three times. The pretest was multiple choice; however, to make the learning effect more evident, we conducted the posttest as a difficult short‐answer test. In the pretest, the rate of correct responses was less than 50% for the three words “molars", “dentin" and “maxilla". In the posttest, despite the change in format to a difficult short‐answer test, the rates of correct responses for all three of the above specific nouns improved. However, for the abstract nouns “checkup" and “prevention", the correct response rates were markedly lower in the posttest. The above results suggest that in the study of English dental terms, a different learning method should be used for abstract terms. (J Osaka Dent Univ 2019; 53: 115‐120)

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  • Koichiro JIN, Takako TOYAMA, Kumiko KAJI, Ayuko MAESOMA, Ai ONISHI, Ma ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 121-126
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    The universal healthcare system in Japan, which has been in place since 1961, gives anyone who suffers disease or injury the security of access to medical care. However, with a more stratified society becoming a major social problem, disparities among local residents in oral health status and the frequency of dental examinations have appeared in recent years. In Japan, many areas have a shortage or lack of dentists, and thus, residents have no access to and cannot easily receive oral healthcare. Unless this situation is resolved, no redress in regional oral health disparities can be expected. In the present study, official data on the current situation in areas with no dentists in Japan were analyzed to obtain basic information for the development of policies and systems that can resolve regional disparities in oral healthcare. The results showed that areas with no dentists tended to have populations of fewer than 100 persons and a population aging rate, which is the percentage of people 65 years old or over in the total population, was 44.9%. This is considerably higher than the national average of 26.0%. In addition, 95 areas designated as having no dentists in a 2009 survey were no longer designated as such in a 2014 survey. The primary reason for this was that the population had decreased to fewer than 50 people within a radius of 4 km by the time of the 2014 survey, indicating that these areas had declining and aging populations. Thus, in the official survey results, it appeared as if the number of areas with no dentists might be decreasing. The results of the present study suggest that, in fact, the situation of oral healthcare in these areas has not improved, but rather, the decline and aging of the population is advancing, particularly in sparsely‐populated regions. To implement effective oral healthcare policies in areas with no dentists, it is essential to gain a detailed understanding of the oral status of local residents and to clarify whether oral health disparities are present within the community. However, the official survey results do not allow such an understanding of actual oral healthcare conditions. The results of the present study suggest that unless effective measures are taken in areas with no dentists, the number of people who find it difficult to access oral healthcare will increase above present levels and regional disparities in oral healthcare will worsen as a result of the declining and aging population. To provide effective oral healthcare to residents living in areas with no dentists, a simplistic approach involving the construction of new dental clinics is not sufficient. Rather, a better understanding of the actual oral health conditions and lifestyles of residents living in such areas is needed, so that specific policies and systems that match the size of the population and the characteristics of each region can be developed. (J Osaka Dent Univ 2019; 53: 121‐126)

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  • Eiichi MATSUBARA
    Type: research-article
    2019 Volume 53 Issue 2 Pages 127-132
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We investigated a series of effective methods for teaching physics as an intensive course for dental students using active learning. When students do not have adequate basic knowledge of a subject, active learning should be introduced after spending adequate time for teaching the basics through lectures. Then we should run the learning cycles that consist of lecture, activity, and presentation. At first, the challenge level of the active learning should be set low, and then gradually raised as the students proceed in the learning cycle, confirming that they are catching up with the class. Thus, we can prevent students from feeling difficulty, and allow them to naturally take part in the class without stress. The frame of these methods essentially agrees with the concept of “deep active learning", which has been proposed recently as a solution for the current problem of active learning. The present style of teaching may be applied to other subjects as well as dentistry. (J Osaka Dent Univ 2019; 53: 127‐132)

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  • Naoki HASHIMOTO, Isao YAMAWAKI, Yoichiro TAGUCHI, Hitoshi AZUMA, Makot ...
    2019 Volume 53 Issue 2 Pages 133-139
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    α‐Tocopherol is the most physiologically active member of the vitamin E family, and its role as an antioxidant in various metabolic processes is widely recognized. However, vitamin E is often deficient in the human body, and only a few reports are available on the effects of periodontal disease on oxidative stress under vitamin E deficient conditions. We investigated the influence of the periodontal pathogen Porphyromonas gingivalis (P. gingivalis) on oxidative stress in human bone marrow mesenchymal cells (BMMCs) at low concentrations of α‐tocopherol. We found an increase in H2O2 production at multiplicity of infection (MOI) of 100 and 1000 at earlier time points and with a concomitant decrease in SOD production. Catalase was produced regardless of P. gingivalis. These results suggest that P. gingivalis reduces the production of some antioxidant enzymes at low concentrations of α‐tocopherol and affects the initial cell proliferation and H2O2 production. (J Osaka Dent Univ 2019; 53: 133‐139)

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  • Takuya NOTOMI, Masakazu INUBUSHI, Tadashige NOZAKI
    Type: research-article
    2019 Volume 53 Issue 2 Pages 141-147
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    Receptor activator of nuclear factor kappa‐B ligand (RANKL) is expressed mainly in osteoblasts and is a critical factor in osteoclast differentiation. The mechanism of RANKL‐induced osteoclastogenesis has been investigated extensively; however, its intracellular transport is still poorly understood. RANKL localizes at lysosomal vesicles and is transported to the vicinity of the cell membrane. This intracellular transportation is regulated by intracellular Ca2+ concentration. In order to investigate the trigger for RANKL lysosomal vesicle fusion to the cell membrane, we generated osteoblast‐like cells stably expressing the channelrhodopsin‐wide receiver (ChRWR) in our previous study. To further investigate the mechanism of vesicle fusion, we focused on synaptotagmin VII (Syt VII), a Ca2+‐sensitive molecule. Light‐induced depolarization increased the levels of membrane‐bound RANKL (mbRANKL), which was reversed by Syt VII knockdown. Addition of an activator for L‐type voltage‐gated Ca2+ channels increased the mbRANKL, whereas knockdown of Syt VII inhibited this activator‐induced increase. These results indicate that depolarization of the osteoblastic cell membrane is a trigger for RANKL lysosomal vesicle fusion to the membrane, and that Syt VII contributes to this vesicle fusion following the opening of L‐type voltage‐gated Ca2+ channels. This mechanism of osteoblastic lysosomal fusion may provide new therapeutic targets for skeletal disorders. (J Osaka Dent Univ 2019; 53: 141‐147)

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  • Masakazu INUBUSHI, Takuya NOTOMI, Tadashige NOZAKI
    Type: research-article
    2019 Volume 53 Issue 2 Pages 149-156
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    Vitamin A is required for normal human health and metabolism. Retinoic acid (RA), a vitamin A metabolite, is critical for cell differentiation and migration. The effects of RA on remodeling of bone have been thoroughly investigated. However, its role is still under debate, especially as it relates to osteoblasts, and the relationship between RA and cell migration is relatively unknown. Using scratch assays, we previously showed that addition of RA promoted the migration of MC3T3‐E1 osteoblast‐like cells (OBs). In the present study, the contribution of RA receptor (RAR) subtypes to RA‐mediated cell migration was investigated using pharmacological experiments. Agonists for subtype RARγ, which plays a major role in osteoblast differentiation, did not affect cell migration, while agonists for RARα promoted cell migration. To confirm the contribution of RARα, knockdown of RARα was performed and the resultant OBs exhibited reduced migration. Addition of RA upregulated mRNA expression of profilin‐1 (PFN1), and overexpression of PFN1 protein promoted OB migration. These results suggest that RA promotes OB migration via RARα. Furthermore, the improvement in cell migration was mediated by RA‐induced upregulation of PFN1 expression. Our findings provide new pharmacological insights into the relationship between RA and osteoblasts. (J Osaka Dent Univ 2019; 53: 149‐156)

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  • Hiroaki YOSHIDA, Sho-ichi YAMAMOTO, Hiroki ISHIKAWA, Mamoru UEDA, Masa ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 157-160
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We did a retrospective study to analyze the features of dry mouth using medical interview data and the SS‐A and SS‐B in the initial blood screening examinations. The records of 330 patients with dry mouth were selected for this study. There were 51 males and 279 females between 27 and 102 years of age with a mean of 67 years. The greatest number of subjects were in the age bracket between 71 and 80 years (37.0% (122/330)), and the male/female ratio was 51 (15.5%):279 (84.5%). Total positive rate for SS‐A was 19.1% (63/330), for which the male/female ratio was 3 (4.8%):60 (95.2%). The greatest number of subjects in this group were in the age bracket between 71 and 80 years 28.6% (18/68). The total positive rate for SS‐B was 7.3% (24/330), for which the male/female ratio was 0 (0%):24 (100%). The greatest number of subjects were in the age bracket between 71 and 80 years (50.0% (12/24)). All of the subjects who were positive for SS‐B were also positive for SS‐A. Sjögren syndrome (SS‐A and SS‐B) are important initial screening factors for dry mouth syndrome in outpatients. (J Osaka Dent Univ 2019; 53: 157‐160)

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  • Kaoru INAMI, Yuri HIGASHI, Kuo-Chiang CHEN, Takeshi KANAGAWA, Naoyuki ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 161-169
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We attempted to verify the reproducibility of treatment using surgical plates and articulators made especially for surgical‐orthodontic treatment, by making preoperative predictions and conducting post‐operative comparative reviews. We conducted a comparative analysis of preoperative cephalometric values, metrics obtained via “paper surgery", and post‐operative cephalometric values. Furthermore, we examined the orthognathic surgery using pre‐and post‐operative data. The post‐operative metrics were similar to the preoperative predictive values. The tendency to mandibular prognathism was improved. We concluded that surgical plates prepared using this articulator are effective and that this method is very useful for making postoperative predictions. (J Osaka Dent Univ 2019; 53: 161‐169)

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  • Toshiki NAKAJIMA, Katsunori TORII, Takamasa FUJII, Junko TANAKA, Masah ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 171-177
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We compared the retentive force of telescopic Ce‐TZP/A crowns in water with the force in the dry state. Ce‐TZP/A was used as the material for both the primary and secondary crowns. The half tapered angles of the primary crown were set to 2° and 4°. The retentive force was measured with applied loads of 25, 50, and 100 N on the occlusal surface of the secondary crown. The maximum resistance value during removal of the secondary crown was deemed to be the retentive force. The measurement of retentive force was performed in the dry state and in water for the same sample. The increased retentive force in water with loads of 25, 50 and 100 N was 2.5, 2.5 and 3.3 N, respectively, for crowns at a half tapered angle of 2°. It was 0.8, 1.1 and 2.1 N, respectively, for those at a half tapered angle of 4°. We found that the retentive force of telescopic Ce‐TZP/A crowns in water was significantly greater than in the dry state. When manufacturing telescopic Ce‐TZP/A crowns, it is necessary to consider the influence of saliva to evaluate the retentive force. (J Osaka Dent Univ 2019; 53: 171‐177)

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  • Masaya MIYAZONO, Katsunori TORII, Mayu YAMAMOTO, Junko TANAKA, Masahir ...
    Type: research-article
    2019 Volume 53 Issue 2 Pages 179-186
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    We attempted to clarify how the impressions imparted on observers are affected by smiles with exposed teeth. Sixty young adults participated in the study, 23 men and 37 women, who had a mean age of 23±2 years. Impressions of composite (average) male and female faces were rated to eliminate individual bias. Ten facial photos were processed for each of 10 adult males with a mean age of 25±2 years and 10 adult females with a mean age of 26±1 years. Three stimulus images were used for each gender: a neutral face (teeth hidden), a smiling face (teeth hidden), and a grinning face (teeth exposed). The average male faces were rated by 30 subjects and the average female faces by the other 30. The semantic differential method was used to rate the impressions. Group ratings were then subjected to factor analysis. The two common factors having the greatest explanatory power were: “Sociable" and “Active" for the male stimulus images and “Friendly" and “Elegant" for the females. Significant differences between stimuli were observed for scores on both the first and second factors. In all cases, the grin was rated highest, followed by the smile and neutral face. We found that when smiling with the teeth exposed, male faces give a strong impression of sociability and activity, while females give a strong impression of friendliness and elegance. (J Osaka Dent Univ 2019; 53: 179‐186)

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  • Tetsuya FUJIMOTO, Hiroshi INOUE, Shun-ichiro HIRANO, Seiji GODA
    Type: research-article
    2019 Volume 53 Issue 2 Pages 187-192
    Published: October 25, 2019
    Released: January 25, 2020
    JOURNALS FREE ACCESS

    The elevated plus maze (EPM) test is widely used with experimental animals to evaluate anxiety, which is most often indicated by the open‐arm staying time. However, little attention has been focused on general spontaneous behaviors (such as locomotor activity, rearing and grooming) using this test. We compared the scores for the same parameter of spontaneous behavior using both the EPM test and the open‐field test (OFT). Then, using an exposure model of bisphenol A (BPA), which is an endocrine‐disrupting chemical, we evaluated its impact on the scores for both tests. In control males, a significant positive correlation was confirmed for all parameters between the two tests. In females, none of the three parameters reached significance. With the BPA exposure model, locomotor activity and rearing showed similar results to those of the control group for both males and females. In grooming, there was a very low correlation between the EPM test and the OFT. When the mean values were compared using the OPT between the control and BPA groups, there was an increase in rearing and a decrease in grooming in the BPA males. On the other hand, in females, effects were seen when using the EPM test. In the BPA females, there were high values for locomotor activity and rearing, and low values for grooming. In grooming behavior, the OPT score was lower in the BPA males, while the EPM test score was lower in the BPA females. The impact of BPA exposure on spontaneous behavior depended on the experimental equipment and gender. (J Osaka Dent Univ 2019; 53: 187‐192)

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