PBT素材歯ブラシの刷毛面積，硬さ及び歯垢除去効果の経時的変化について : ランダム化比較試験

内容の要約広島大学(Hiroshima University)博士(口腔健康科学)Doctor of Philosophy in Oral Health Sciencedoctora

Changes in the Bristle Stiffness of Polybutylene Terephthalate Manual Toothbrushes over 3 Months: A Randomized Controlled Trial

We previously reported that polybutylene terephthalate (PBT) toothbrushes become less effective for plaque removal after two months of use. However, it remains unknown how the bristle stiffness of PBT toothbrushes changes after several months of use. We performed a single-center randomized controlled trial to evaluate the bristle stiffness and bristle splaying of soft and medium manual toothbrushes among dental and medical students of Hiroshima University. Subjects were 80 participants who met the criteria. Participants were randomly assigned to the soft toothbrush group (n = 40) or the medium toothbrush group (n = 40). We collected toothbrushes immediately after first use (T0), after one month of use (T1), after two months of use (T2), and after three months of use (T3). Bristle stiffness was measured according to the International Organization for Standardization (ISO) 22254. The mean bristle stiffness (N/cm2) of soft and medium toothbrushes was significantly lower at T2 and T3 than at T0 (T2 vs. T0, soft; 3.63 vs. 3.89, P < 0.01 and medium; 4.33 vs. 4.52, P < 0.05, respectively, and T3 vs. T0, 3.62 vs. 3.89, p < 0.01 and 4.18 vs. 4.52, p < 0.001, respectively). Bristle stiffness was significantly reduced in soft and medium PBT toothbrushes after two months of use

Analysis of the Deflection, Bristle Splaying, and Abrasion of a Single Tuft of a Polybutylene Terephthalate Toothbrush after Use: A Randomized Controlled Trial

The aim of this study is to clarify the deflection, splaying, and abrasion of single tufts of polybutylene terephthalate (PBT) toothbrushes after use. A single-center randomized controlled trial is performed. The changes in deflection, bristle splaying, and abrasion are investigated for the middle single tuft of the top line (top–middle tuft) and the middle single tuft of the bottom line (bottom–middle tuft) of PBT toothbrushes with medium stiffness after 1 month, 2 months, and 3 months of use by 34 participants. A soft-material bending-resistance tester is used to assess the deflection of the single tufts. The deflection value of the top–middle tuft significantly increased after 1 month of use compared with the baseline. In contrast, the deflection of the bottom–middle tuft significantly increased after 3 months of use compared with the baseline and after 1 month and 2 months of use. Importantly, the change in deflection was distinctly different between the top– and bottom–middle tufts. The bristle splaying of both tufts significantly increased after use, but a significant change in bristle abrasion was not found. The bending stiffness of the top tuft of a PBT toothbrush may decrease more rapidly than that of the bottom tuft with use

Development and evaluation of the “Toothbrushing Timer with Information on Toothbrushes” application: A prospective cohort pilot study

Abstract Objectives For people, it is challenging to be conscious of the appropriate toothbrushing time to maintain good oral health in daily life. The aim of this study was to preliminarily examine the utility of an application (app) that combines a toothbrushing timer and information on toothbrushes. Materials and Methods We developed the “Toothbrushing Timer with Information on Toothbrushes” app to help users ensure appropriate toothbrushing time and learn about the beneficial characteristics of toothbrushes. A total of 18 participants were registered for the study. At baseline (T0) and after 1 month (T1) of app usage, study participants answered a digital questionnaire that comprised three questions on oral health practice, self‐efficacy in oral hygiene, and quality of life related to oral health (Oral Health Impact Profile‐14 [OHIP‐14]). Results Five participants were excluded from the analysis as they did not answer the digital questionnaire. Finally, 13 participants completed the survey with a follow‐up of 1 month. The 13 participants were grouped into health professionals (n = 8) and non‐health professionals (n = 5). The total scores for oral health practice and self‐efficacy related to oral hygiene increased after a month of app usage in health professional and non‐health professional groups. However, there were no significant differences between T0 and T1 in either group. The total score of OHIP‐14 was lower at T1 than at T0 in both groups. Therefore, participants showed better oral health practice, self‐efficacy in oral hygiene, and quality of life related to oral health at T1 compared with that at T0. Conclusions Our app showed positive results for the users and is useful in maintaining and promoting oral health awareness and practice. However, our pilot study lacks sufficient power and did not yield significant differences. Therefore, high‐quality clinical trials with larger sample sizes are warranted for further improvement and evaluation

Contribution of Local and Transboundary Air Pollution to the Urban Air Quality of Fukuoka, Japan

Transboundary air pollution (TAP) and local air pollution (LAP) influence the air quality of urban areas. Fukuoka, located on the west side of Japan and affected by TAP from the Asian continent, is a unique example for understanding the contribution of LAP and TAP. Gaseous species and particulate matter (PM) were measured for approximately three weeks in Fukuoka in the winter of 2018. We classified two distinctive periods, LAP and TAP, based on wind speed. The classification was supported by variations in the concentration of gaseous species and by backward trajectories. Most air pollutants, including NOx and PM, were high in the LAP period and low in the TAP period. However, ozone was the exception. Therefore, our findings suggest that reducing local emissions is necessary. Ozone was higher in the TAP period, and the variation in ozone concentration was relatively small, indicating that ozone was produced outside of the city and transported to Fukuoka. Thus, air pollutants must also be reduced at a regional scale, including in China

Influence of Trans-Boundary Air Pollution on the Urban Atmosphere in Fukuoka, Japan

To understand the influence of trans-boundary air pollution on the air quality of Fukuoka, the mass concentration and chemical composition of fine particulate matter (PM) were observed at urban (Fukuoka) and rural (Fukue Island) sites in the northern Kyushu area in Japan. Chemical composition was measured using an aerosol mass spectrometer. Organic aerosol (OA) data were analyzed by the positive matrix factorization (PMF) method. Sulfate and low-volatile oxygenated OA (LV-OOA) were dominant for all of the PM2.5 mass variations on Fukue Island, where the trans-boundary air pollution is dominant in the winter-spring season. In Fukuoka, however, sulfate accounted for the largest fraction of total chemical species under high PM2.5 mass concentrations (>35 µg·m−3), while organics and nitrate made up a large fraction under low PM2.5 (<10 µg·m−3). Under the high PM2.5 condition, LV-OOA was also dominant. This indicates that high PM2.5 mass concentrations were attributed to the long-range transport of air pollution. Although the trans-boundary air pollution prevails in the winter-spring season, high sulfate concentrations were observed in the summer of 2012. In addition to the volcanic activities and photochemical reactions, long-range, trans-boundary air pollutions are influential factors not only in winter-spring but also in summer

The Associations of Periodontopathic Bacteria and Oral Candida with Periodontal Inflamed Surface Area in Older Adults Receiving Supportive Periodontal Therapy

The periodontal inflamed surface area (PISA) has been proposed for assessment of the total periodontal inflammatory status in people with periodontitis. This study was performed to investigate the associations of periodontopathic bacteria and candida with PISA in older people. We enrolled 100 patients aged ≥ 60 years who visited Hiroshima University Hospital. PISA and periodontal epithelial surface area (PESA) were calculated in each patient. Oral rinse samples were collected for DNA extraction. Periodontopathic bacteria and candida were detected by polymerase chain reaction. The mean values of PISA and PESA were significantly greater in T.forsythia-positive patients than in T.forsythia-negative patients. T.forsythia/C. albicans double-positive patients exhibited significantly greater PISA values than did non-double-positive patients. Additionally, PISA values were significantly greater in T. forsythia//T. denticola/C. albicans triple-positive patients than in T. forsythia//T. denticola/C. albicans non-triple-positive patients (p = 0.02). Propensity score-matching was performed between periodontopathic bacteria-positive and -negative patients using propensity scores generated from clinical factors. Importantly, T.forsythia/T. denticola double-positive patients exhibited significantly greater PISA values than non-double-positive patients among 72 propensity score-matched patients. Our preliminary results highlight the importance of the presence of T.forsythia and T. denticola for periodontal inflammation severity in older Japanese people