Objective To investigate the interrelationships among concerns regarding dental visits, the status of regular dental visits, and periodontal health during the coronavirus disease 2019 (COVID‐19) pandemic. Background Continuous oral health care and regular dental visits are important for maintaining periodontal health. Due to the possibility of contracting COVID‐19, individuals have been reluctant to visit medical institutions. It is unclear how the periodontal health of the Japanese population has been affected by the interruption of regular dental visits during the COVID‐19 pandemic and how concerns regarding dental visits have affected attendance at regular dental visits. Methods This study included 199 Japanese office workers in one municipal office at Fukuoka Prefecture, Japan (average age = 42.6 years; age range = 19–77 years; 123 men and 76 women). Periodontitis was defined based on a full‐mouth periodontal examination. The status of regular dental visits during the COVID‐19 pandemic and concerns regarding dental visits were obtained via questionnaire. We tested the hypothesis that concerns regarding dental visits would indirectly affect periodontal health through the interruption of regular dental visits during the COVID‐19 pandemic. We used mediation analysis, in which concerns regarding dental visits (present or absent) were set as the exposure, periodontitis (present or absent) was set as the outcome, and the status of regular dental visits (continued during the COVID‐19 pandemic or not) was set as the mediator. Results Of the 199 study participants, 108 had a habit of attending regular dental visits. Of these, 31 (28.7%) discontinued regular dental visits during the COVID‐19 pandemic. Compared to the individuals who continued regular dental visits, those who discontinued regular dental visits had a higher prevalence of periodontitis (49.4% vs 77.4%, p < 0.05) and concerns regarding dental visits (22.1% vs 64.5%, p < 0.05). Discontinuing regular dental visits significantly mediated the association between concerns regarding dental visits and periodontitis (natural indirect effect: odds ratio = 1.68, 95% confidence interval = 1.02–2.79, proportion mediated = 64.3%). Conclusion The study results showed that individuals who discontinued regular dental visits during the COVID‐19 pandemic due to concerns regarding dental visits had relatively poor periodontal health.

This study aimed to explore whether the Trypsin-Like Peptidase Activity Assay Kit (TLP-AA-Kit), which measures the activity of N-benzoyl-dl-arginine peptidase (trypsin-like peptidase), can be used as a reliable tool for periodontitis detection in population-based surveillance. In total, 105 individuals underwent a full-mouth periodontal examination and provided tongue swabs as specimens for further analyses. The results of the TLP-AA-Kit were scored between 1 and 5; higher scores indicated higher trypsin concentrations. Receiver operating characteristic analyses were used to evaluate the predictive validity of the TLP-AA-Kit, where the periodontitis case definition provided by the Centers for Disease Control/American Academy of Periodontology served as the reference. Severe and moderate periodontitis were identified in 4.8% and 16.2% of the study population, respectively. The TLP-AA-Kit showed high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.93 (95% confidence interval = 0.88–0.99). However, the diagnostic accuracy of the TLP-AA-Kit for moderate/severe periodontitis was not reliable. While further studies are necessary to validate our results, the results provided herein highlight the potential of the TLP-AA-Kit as a useful tool for the detection of periodontitis, particularly in severe cases, for population-based surveillance.

Objectives N-benzoyl-DL-arginine peptidase (trypsin-like peptidase) is specifically produced by certain strains of periodontitis-associated bacteria. We aimed to examine the effectiveness of an objectively quantified trypsin-like peptidase activity assay (TLP-AA) for detecting severe periodontitis. Methods The study population included 347 adults (108 men and 239 women; average age, 43.3 years) who underwent a full-mouth periodontal examination. Specimens for the TLP-AA were obtained using tongue swabs. Using a color reader, the TLP-AA results were obtained as a* values, with higher positive a* values indicating an increased intense enzymatic activity. The predictive validity of the TLP-AA results for severe periodontitis was assessed using receiver operating characteristic curve analysis and the periodontitis case definition provided by the Centers for Disease Control and Prevention/American Academy of Periodontology as the gold standard. Furthermore, multivariable logistic regression analyses were performed to predict severe periodontitis using the TLP-AA results and health characteristics, as the exposure variables. Results Severe periodontitis was observed in 5.2% of the participants. TLP-AA had high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.83 (95% confidence interval [CI]: 0.75–0.92). The cut-off score for the a* value that best differentiated individuals with severe periodontitis was 0.09, with a sensitivity of 83% and specificity of 77%. Multivariable logistic regression analyses revealed that the TLP-AA results were significantly associated with severe periodontitis after adjusting for health characteristics (adjusted odds ratios: 1.90 [95% CI: 1.37–2.62] for the a* value). Conclusions Objectively quantified TLP-AA results are potentially useful for detecting severe periodontitis in epidemiological surveillance.

No abstract

We aimed to assess the validity of the self-report questionnaire for periodontitis in a Japanese population. A Japanese 9-item self-report questionnaire, developed by translating English-version questions that were used to detect periodontitis, was validated against full-mouth clinically-assessed periodontitis in 949 Japanese adults (average age = 43.2 years). Multivariable logistic regression modeling was used to calculate the area under the receiver operating characteristic curve (AUC), wherein the periodontitis case definition of the Centers for Disease Control and Prevention/American Academy of Periodontology was considered the gold standard. Severe, moderate, and mild periodontitis were identified in 6.2%, 30.0%, and 6.7% of the study population, respectively. Self-reported oral health questions combined with socio-demographic and health-related variables had an AUC > 0.70 (range, 0.71–0.87) for any periodontitis category. Four oral health questions (“have gum disease,” “loose tooth,” “lost bone,” and “bleeding gums”) were selected in the parsimonious model for severe periodontitis. The periodontitis screening score generated by the responses to these four questions had an AUC, sensitivity, and specificity of 0.82, 73.1%, and 74.3%, respectively, where the cut-off was set at 2 points. In conclusion, a locally adapted version of the self-report questionnaire had an acceptable diagnostic capacity for the detection of periodontitis in this study population.

Immunoreceptors expressed on osteoclast precursor cells modify osteoclast differentiation and bone resorption activity. Dectin‐1 is a lectin receptor of β‐glucan and is specifically expressed in osteoclast precursor cells. In this study, we evaluated the bioactivity of β‐glucan on receptor activator of nuclear factor‐kappa B ligand (RANKL)‐induced osteoclastogenesis and observed that glucan from baker's yeast inhibited this process in mouse bone marrow cells and dectin‐1–overexpressing RAW264.7 (d‐RAW) cells. In conjunction, RANKL‐induced nuclear factor of activated T cell c1 expression was suppressed, subsequently downregulating TRAP and Oc‐stamp. Additionally, nuclear factor‐kappa B activation and the expression of c‐fos and Blimp1 were reduced in d‐RAW cells. Furthermore, glucan from baker's yeast induced the degradation of Syk protein, essential factor for osteoclastogenesis. These results suggest that glucan from baker's yeast suppresses RANKL‐induced osteoclastogenesis and can be applied as a new treatment strategy for bone‐related diseases.

Although the anti-tumor and anti-infective properties of β-glucans have been well-discussed, their role in bone metabolism has not been reviewed so far. This review discusses the biological effects of β-glucans on bone metabolisms, especially on bone-resorbing osteoclasts, which are differentiated from hematopoietic precursors. Multiple immunoreceptors that can recognize β-glucans were reported to be expressed in osteoclast precursors. Coordinated co-stimulatory signals mediated by these immunoreceptors are important for the regulation of osteoclastogenesis and bone remodeling. Curdlan from the bacterium Alcaligenes faecalis negatively regulates osteoclast differentiation in vitro by affecting both the osteoclast precursors and osteoclast-supporting cells. We also showed that laminarin, lichenan, and glucan from baker’s yeast, as well as β-1,3-glucan from Euglema gracilisas, inhibit the osteoclast formation in bone marrow cells. Consistent with these findings, systemic and local administration of β-glucan derived from Aureobasidium pullulans and Saccharomyces cerevisiae suppressed bone resorption in vivo. However, zymosan derived from S. cerevisiae stimulated the bone resorption activity and is widely used to induce arthritis in animal models. Additional research concerning the relationship between the molecular structure of β-glucan and its effect on osteoclastic bone resorption will be beneficial for the development of novel treatment strategies for bone-related diseases.

Aim To evaluate the association between sleep duration and severe periodontitis in Japanese workers. Materials and methods This cross‐sectional study included 1130 workers (mean age 43.0 years) who underwent full‐mouth periodontal examinations and health check‐ups and completed a self‐administered questionnaire that included questions on sleep duration. Logistic regression and a restricted cubic spline model were used to analyse the data. Results Severe periodontitis was identified in 6.3% of the study population. Those with <5, 5–5.9, 6–6.9, 7–7.9, and ≥8 hr of sleep were 6.7%, 17.4%, 40.3%, 26.3%, and 8.9%, respectively. After adjusting for potential confounders, study participants who slept <5 hr were more likely to have severe periodontitis (adjusted odds ratio = 2.64; 95% confidence interval = 1.06–6.60) than those who slept 7–7.9 hr. The spline model, with a reference value of 399 min (the median sleep duration), showed a non‐linear association between sleep duration and severe periodontitis, where an increased prevalence of severe periodontitis was observed only among those with a shorter sleep duration. The prevalence of severe periodontitis did not increase with longer sleep duration. Conclusions Short sleep duration was associated with severe periodontitis in this cohort of Japanese adults.