Journal of Nippon Oral Health Sciences
Online ISSN : 2434-7116
Print ISSN : 2434-7108
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Original Article
  • Mikue KOYAMA, Rie IKEDA
    2019 Volume 9 Issue 1 Pages 2-9
    Published: 2019
    Released: January 24, 2020

    Improvement in oral function not only improves swallowing function but also helps prevent lifestyle-related diseases, such as stroke and diabetes. Therefore, modern dental care needs to provide support for overall body management as well as oral health management. A significant correlation has been reported between oral function indicated by maximum lip pressure and maximum tongue pressure and motor function evaluated by grip strength and the Timed Up and Go (TUG) Test in older persons. However, the correlation between oral and motor function in young adults has not been clarified. This study aimed to investigate the correlation between oral and motor function in young adults, and to examine the effectiveness of oral health support for maintaining general health.

    The participants were 24 female students enrolled at the Department of Dental Hygiene in Nippon Dental University College at Tokyo. We measured maximum tongue pressure to evaluate oral function. We also measured grip strength, TUG, and the 30-Second Chair Stand Test (CS-30) to evaluate motor function. Subsequently, we statistically investigated the correlation between oral and motor function.

    We found a significant correlation between maximum tongue pressure and grip strength (r = 0.560 (p <0.001)). However, no significant correlation was found between maximum tongue pressure and TUG, or between maximum tongue pressure and CS-30.

    Grip strength is considered to indicate the basic physical strength of the entire body. Therefore, our results indicate a correlation between oral function and general physical fitness. The findings suggest the need for dental hygienists to understand the correlation between oral function and general physical fitness and to support patients in the acquisition of exercise habits to maintain eating and swallowing functions throughout their life.

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  • Masumi HIRANO, Shunya OKA, Masato MIKAMI, Akane IMAI
    Type: research-article
    2019 Volume 9 Issue 1 Pages 10-17
    Published: 2019
    Released: January 24, 2020

    Periodontal disease is caused by bacterial infection of the oral cavity, and Porphyromonas gingivalis (P. gingivalis) is the main cause of chronic periodontitis. Regular toothbrushing and the routine use of antibacterial agents are common methods of plaque control. The use of so-called “probiotic” microorganisms to prevent infection in this context has recently attracted increased attention. The current study assessed the bactericidal activities of Lactobacillus salivarius, Lactobacillus acidophilus, and Lactobacillus casei—which are commonly used as probiotics—against P. gingivalis. Mixed cultures containing each Lactobacillus species and P. gingivalis in equal concentrations were generated, and the subsequent numbers of viable bacteria were measured. The odors of mixed cultures were also measured. Furthermore, the disc diffusion method was used to investigate P. gingivalis viability in the presence of solutions derived from Lactobacillus cultures in conjunction with the measurement of inhibitory zones. Bactericidal activity against P. gingivalis was observed in all mixed cultures. Odor was also reduced. Notably however, in disc diffusion antimicrobial tests using culture-derived solutions there were no significant differences in any inhibitory zones. Live lactic acid bacteria may exert bactericidal effects on P. gingivalis. In the present study, it was suggested new possibilities for the prevention of periodontal disease using probiotics, including Lactobacillus bacteria.

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  • Kotoka SATO, Mari SUDA
    Type: research-article
    2019 Volume 9 Issue 1 Pages 18-26
    Published: 2019
    Released: January 24, 2020

    In recent years, dentists and dental hygienists have had increased opportunities to consult on occlusal conditions and oral habits at health checkups for young children. This study aimed to clarify the correlation between the oral habits of 3 to 5-year-old children, who are still developing oral habits, and the personal oral hygiene practices of their parents. The obtained results were expected to contribute to dental health instruction for reducing the incidence of poor oral habits and increasing parents’ interest in dental care.

    The questionnaire survey was conducted with parents of 5 to 6-year-old children participating in the “Teeth and Oral Health Week Project” held in the Hadano and Isehara Districts of Kanagawa Prefecture and parents of 3 to 6-year-old children attending K nursery school in Tokyo.

    The most common oral habit of children was “finger sucking” at 29.7%, whereas “nothing in particular” accounted for 34.9%. Less than half of the children had no oral habits. Therefore, many children had some kind of oral habit. The results showed a significant correlation between the frequency of parents assisting with teeth brushing and children having or not having a finger-sucking habit.

    Parents who practice good personal oral hygiene can reduce or eliminate the occurrence of poor oral habits in children. This finding suggests the importance of a thorough approach to providing instruction on personal oral hygiene practices to both children and parents.

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  • Chihiro KUWATA, Tsutomu SATO, Rie IKEDA
    Type: research-article
    2019 Volume 9 Issue 1 Pages 27-32
    Published: 2019
    Released: January 24, 2020

    The importance of extending healthy life expectancy has recently been greatly emphasized

    and the public’s awareness of health is increasing. Acquiring regular eating habits is extremely important to maintain and improve health. Fermented foods have been considered good for health for a relatively long time. Lactic acid bacteria are typical bacteria found in fermented foods, and they are known to stimulate the immune system, regulate the intestines, and reduce cholesterol. In the field of dentistry, these bacteria have been reported to have an inhibitory effect on the development of caries and the growth of bacteria associated with periodontal disease, and oral care products containing various lactic acid bacteria to make use of these effects have been developed and marketed.

    The aim of this study was to examine the growth inhibitory effect of commercially-available foods containing lactic acid bacteria on Streptococcus mutans (S.mutans) and Candida albicans (C.albicans) in oral care, and to evaluate the usefulness of these products as oral care tools. Specifically, three types of test foods were dissolved to prepare a test food solution, and we measured the proliferative ability of S.mutans and C.albicans in culture solutions with set amounts of test food added. The results demonstrated that there is a difference in their effect on the growth of S.mutans and C.albicans even in food marketed as containing lactic acid bacteria.

    In future studies, it will be necessary to examine the duration of this effect and determine whether this effect holds in patients with oral disease, as well as to investigate whether there is a growth inhibitory effect on periodontal disease bacteria other than S. mutans and C. albicans.

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