Nihon Shishubyo Gakkai Kaishi (Journal of the Japanese Society of Periodontology)
Online ISSN : 1880-408X
Print ISSN : 0385-0110
ISSN-L : 0385-0110
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Original Work
  • Kento Tsubosaki, Tomotaka Kato, Ryoko Iwata, Yuuki Maeda, Naoki Mino, ...
    2021 Volume 63 Issue 1 Pages 1-10
    Published: March 31, 2021
    Released: March 30, 2021

    Although many toothbrushes of various forms are now manufactured, there are few reports of comparison of the effectiveness of toothbrushes used under the same conditions. Few studies have reported the effects of brushing proficiency and toothbrush shape on the plaque removal efficacy. In this study, we compared the plaque removal effects of five different toothbrushes in two groups with different levels of brushing proficiency. Ten dentists (Group P), and 10 volunteers with poor brushing skills and no experience of receiving brushing instructions from a dental clinic (Group V) were asked to brush with five different types of toothbrushes. All permanent teeth, excluding the wisdom teeth, excessive teeth, and teeth undergoing treatment, remained stained before and after brushing, and the plaque scores before and after brushing were measured using the Plaque Control Record.

    The results showed that the plaque removal rate was lower in Group V than in Group P, regardless of which toothbrush was used, although the difference was not significant. On the other hand, the plaque removal rate in group P was higher than that in group V regardless of which toothbrush was used, and the rates of plaque removal in Group P differed depending on the type of toothbrush used. In particular, the plaque removal rate was higher in the subjects who used toothbrushes with good maneuverability, designed to make it easy for the bristles to reach the tooth surface and to apply proper brushing pressure.

    These results suggest that toothbrushes that are effective in removing plaques differ in terms of their level of effectiveness.

  • Saki Mishiro, Hiroko Igarashi-Takeuchi, Yukihiro Numabe
    2021 Volume 63 Issue 1 Pages 11-23
    Published: March 31, 2021
    Released: March 30, 2021

    Cannabidiol (CBD) in cannabis has an anti-inflammatory effect, and its receptor, G protein-coupled receptor 55 (GPR55), has been suggested to be involved in the regulation of inflammation. Here, we investigated GPR55 expression in human gingival fibroblasts (HGFs) and anti-inflammatory effects of CBD via GPR55.

    GPR55 expression and localization were confirmed in control, LPS-stimulated (LPS), CBD-treated and LPS-stimulated (CBD+LPS), and CBD-treated (CBD) groups. We also compared interleukin (IL) -6 and IL-8 protein production in each group.

    GPR55 expression levels were significantly reduced in the LPS and CBD+LPS groups (p<0.05) compared to control and CBD groups, and GPR55 protein was found diffusely in the cytoplasm of HGFs in all groups. In addition, IL-6 and IL-8 production was significantly reduced in non-knockdown HGFs in the CBD+LPS group compared to the LPS group (p<0.05). By contrast, in GPR55-knockdown HGFs, there was a significant increase in IL-6 and IL-8 production in the LPS and CBD+LPS groups compared with the control groups (p<0.05), but there was no significant difference in IL-6 and IL-8 production in GPR55-knockdown HGFs between the LPS and CBD+LPS groups.

    In this study, we confirmed the homeostatic expression of GPR55 in HGFs and its tendency to decrease in expression during inflammation. It was also shown that part of an anti-inflammatory effect by CBD may be mediated by GPR55.

Educational Award
  • Jun-ichi Otogoto, Takeo Fujii
    2021 Volume 63 Issue 1 Pages 24-30
    Published: March 31, 2021
    Released: March 30, 2021

    Matsumoto Dental University Hospital has been implementing a clinical training program for dentists immediately after their graduation, involving training and guidance for the treatment of periodontal disease. In this paper, we introduce four systems that are used to perform periodontal treatment in clinical training. In addition, we report a comparison of the results of periodontal disease examination and skills.

    Prior to the compulsory clinical training, the clinical training SYStem (SYSTEM 0) did not promote clinical training for each caries, and periodontal disease were required for periodontal tissue examination and scaling/root planning (SRP).

    In the periodontal treatment training SYStem (SYSTEM 1) used for clinical training from 2001 to 2005, a medical dividend system per oral cavity was started.

    In the periodontal treatment training SYStem (SYSTEM 2) adopted from 2006 to 2010, the number of dividend cases was increased and guidance from periodontal disease-certified doctors was enhanced. Furthermore, it was possible to secure a dedicated medical chair that could be used for periodontal treatment by clinical training dentists after SYSTEM 2 was adopted.

    In the periodontal treatment training SYStem (SYSTEM 3) adopted from 2011 onwards, basic periodontal treatment is performed for over a month with the consent of the patient, during which oral hygienists provide oral cleaning guidance.

    As for the training results obtained with the four training SYStems, the number of cases of basic periodontal therapy did not exceed up to SYSTEM 2. However, SYSTEM 3 increased the number of cases of basic periodontal therapy such as SRP and periodontal surgery. The number of cases undergoing surgery also increased. In addition, enhancement of the training content was shown by the increase in the number of case reports, including of maintenance after periodontal treatment, cases of transition to supportive periodontal therapy (SPT) after periodontal treatment.

    Establishment of a training system for postgraduate dentists immediately after graduation to actively perform basic periodontal therapy increased the interest of dentists in clinical training in treating clinical cases. With the current guidance SYTEM 3, trainees can perform periodontal treatment at any clinical site after completing the training, which is the path to transition to a periodontal disease certified dentist/specialist.