Journal of Nippon Oral Health Sciences
Online ISSN : 2434-7116
Print ISSN : 2434-7108
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Showing 1-11 articles out of 11 articles from the selected issue
Original Article
  • Kayo KOIWA, Fumihiro SATO
    Type: research-article
    2020 Volume 10 Issue 1 Pages 1-6
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    This study aimed to examine how different manufacturing methods affect the resilience of fiber copings installed in the abutments for fiber-reinforced dental bridges and identify an effective manufacturing method.

    Five manufacturing conditions were examined: 1) the coping is made of only a main fiber frame (control condition); 2) the fiber mesh is cut, stacked at a 45-degree angle, and filled with Dentin Flow; 3) the same as 2 but without the filling; 4) the same as 2 but without the cutting; and 5) same as 2 but with neither the cutting nor the filling.

    Both cutting conditions (2 and 3) were associated with poorer fracture resistance compared with the control condition. Fracture resistance was similar for both cutting conditions, despite the difference in use of Dentin Flow. As for the impact of filling, condition 4 (filled) exhibited a similar fracture resistance to control, whereas condition 5 (no filling) exhibited a poorer fracture resistance. However, none of the results proved statistically significant.

    The results of this study imply that the most effective manufacturing method for fiber coping is one in which the fiber mesh is stacked at a 45-degree angle without cutting, pressed, and then filled with Dentin Flow.

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  • Mai USUI, Rie IKEDA
    Type: research-article
    2020 Volume 10 Issue 1 Pages 7-16
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    Salivary gland massages are known to be effective in prompting saliva secretion. Salivary secretion can also be prompted by inhaling essential oils. However, little is known about how well these methods work when combined. This study aimed to clarify how olfactory stimulation (inhalation of essential oils) combined with tactile stimulation (salivary gland massage) effects saliva secretion in young people.

    The participants were 24 women students who were enrolled in a dental hygiene or advanced dental hygiene course at the Nippon Dental University College in Tokyo. Salivary secretion was measured under the following conditions: control (no stimulation), tactile stimulation (salivary gland massage), olfactory stimulation (aromatherapy using black pepper or lavender oil), and a combination of tactile and olfactory stimulation.

    All three stimulation conditions were associated with significantly greater saliva secretion compared with the control condition. Combined tactile-olfactory stimulation, especially with black pepper oil, was associated with the greatest saliva secretion, suggesting that this combined method is effective.

    The results imply that aromatherapy combined with salivary gland massage is effective in prompting saliva secretion. It is necessary to raise awareness on the usage and effectiveness of aromatherapy in dental care.

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  • Shuya SHIRAKI, Tsutomu SATO
    Type: research-article
    2020 Volume 10 Issue 1 Pages 17-24
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    Resin dentures are highly absorbent, meaning that when worn, they will absorb saliva, thus encouraging bacterial and fungal growth. This study aimed to develop a denture base that is clinically viable and helps prevent oral diseases, such as oral thrush and tooth decay, as well as the systemic diseases resulting from the latter. We examined a number of resin samples; some contained both catechins and an antimicrobial substance derived from a culture supernatant of Bacillus subtilis (DM0507®), whereas others contained either catechins or DM0507®. The samples were evaluated using the following metrics: antibacterial/adhesion inhibitory effects, durability of such effects, mechanical strength, and color. Samples containing both catechins and DM0507®, and those containing one or the other, exhibited antibacterial effects against Candida albicans and Streptococcus mutans, regardless of differences in weight ratio. The antibacterial effect was still observed in the samples four weeks later. The resins also exhibited an adhesion-inhibiting effect against Streptococcus mutans, with the greatest effect observed in samples containing both DM0507® and catechins. The adhesion-inhibiting effect was still observed in the samples four weeks later. No inter-sample differences were observed in mechanical strength. Different formulations of DM0507® and catechin compounds affected the levels of color differences. Our results imply that resins containing DM0507® and catechins may, with the right ratios, serve as material for clinically viable denture bases that can contribute to oral health.

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  • Kaoru SATO, Masato MIKAMI, Shiho MOTOI, Akane IMAI
    Type: research-article
    2020 Volume 10 Issue 1 Pages 25-33
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    Caries and periodontal disease affect the body’s general condition and interfere with activities of daily living. There are various means to prevent these. Xylitol is reportedly effective for caries, but there are few reports on its association with periodontal disease. Erythritol, a type of sugar alcohol, is a non-metabolizable sweetener, although unlike xylitol, it is easily digested and absorbed. Herein, we focused on sugar alcohols, and investigated the effects of xylitol and erythritol on the cariogenic pathogen Streptococcus mutans (S. mutans) and the periodontal pathogen Porphyromonas gingivalis (P. gingivalis).

    S. mutans and P. gingivalis were each cultured in a medium containing 1% sugar alcohols, and the turbidity (optical density at 560 nm) was measured as growth. Moreover, to examine the effects of sugar alcohol concentration on the growth of S. mutans and P. gingivalis, sugar alcohols at concentrations of 0.63%, 1.25%, 2.5%, 5%, 10% and 20% were mixed and cultured, and spot tests and turbidity measurements were performed.

    In this study, xylitol and erythritol exhibited antiproliferative effects on S. mutans and P. gingivalis. To date, xylitol has been known mainly for its association with caries prevention; however, it may prevent periodontal disease at high concentrations. Erythritol may also be expected to prevent caries and periodontal disease.

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  • Saya KUZUSHIMA, Rie IKEDA
    Type: research-article
    2020 Volume 10 Issue 1 Pages 34-41
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    In recent years, public demand for the provision of oral health management has grown.

    The purpose of this study is to investigate the oral health management of dental hygiene and nursing students, especially their knowledge and the content that they learn in the area of oral hygiene management, and to examine any differences in knowledge between them and determine the association between the educational content of both student groups.

    The survey subjects were 73 dental hygiene students enrolled in a 3-year junior college in the metropolitan area and 70 nursing students enrolled in a 4-year university in the metropolitan area. An anonymous, self-administered questionnaire was distributed and recovered by mail, and the responses were summed for statistical analysis.

    The results of this survey showed that dental hygiene students had more learning opportunities about teeth and oral cavity than nursing students. Many dental hygiene students and nursing students have experience performing oral health management practical training on each other within the group, and it became clear that both dental hygiene and nursing students were decidedly aware of oral health management. It was also revealed that neither dental hygiene nor nursing students sufficiently recognized each other’s duties, indicating the need for better information sharing and professional cooperation in the future.

    From this study, we believe that dental hygienists must actively provide information and cooperate with nurses as experts in oral health management.

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  • Sachiyo SHIBATA, Masako NOMURA
    Type: research-article
    2020 Volume 10 Issue 1 Pages 42-48
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    The aim of this study is to compare the attitude and satisfaction of patients who regularly visit dental clinics and receive regular professional care and guidance from dental hygienists, depending on whether or not they have assigned dental hygienists, and to determine the reasons patients engage in regular dental checkups. In addition, to improve patient satisfaction, we wish to investigate patient requests and to link them to improving patients’ regular checkups.

    The study subjects were 120 adult patients who visited the dental clinic in July and August 2019 for a regular dental checkups. This included 60 patients with an assigned dental hygienist, and 60 patients with no assigned dental hygienist. At the time of the visit, a dentist or dental hygienist verbally explained the purpose of the study to participants, and only those who gave consent were surveyed, using an anonymous, self-administered questionnaire.

    All respondents, whether they had an assigned dental hygienist or not, indicated that they would like to receive a dental checkup in the future. However, significantly more patients with an assigned dental hygienist gave “there is a reliable dental hygienist” as a reason for continuing, suggesting that assignment encourages patients to continue regular checkups.

    The study results reveal that not only does the assignment of dental hygienists encourage patients to continue regular dental checkups, but it is also effective for dental hygienists. Furthermore, it may play an important role in aiming to extend the healthy life expectancy of assigned patients as their regular dental hygienist.

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  • Mizuho ONO, Rie IKEDA
    Type: research-article
    2020 Volume 10 Issue 1 Pages 49-57
    Published: 2020
    Released: January 18, 2021
    JOURNALS FREE ACCESS

    In Japan, few universities provide students with regular dental checkups, and dental health education is not mandatory.

    The purpose of this study was to clarify the relationship between the dental health behavior of non-medical university students and the dental health education they have received in the past. The study also examined how an intervention that uses a tool for counting intraoral bacteria affects dental health behavior.

    The study was conducted with 50 non-medical university students. Before and after the intervention, the students completed an anonymous self-administered survey. For the pre-intervention survey, intraoral bacteria count was measured using a bacteria counter, and the participants were informed of the results.

    The results of the study indicated that while there are several school-based opportunities for dental education during elementary school, these progressively decrease with age. Findings also suggested that daily oral hygiene behavior practiced at home during childhood predicts dental behavior in adulthood and also shapes the oral environment. Additionally, most of the students reported that measuring intraoral bacteria count was effective for themselves.

    In view of the results obtained, it is necessary to raise awareness about the effectiveness of home-based dental health education during childhood, and to provide more dental education opportunities for university students, who currently have few such opportunities. The results also imply that a dental education approach which uses a tool for measuring intraoral bacteria count is effective for encouraging favorable changes in dental health behavior.

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