Association between Household Exposure to Secondhand Smoke and Dental Caries among Japanese Young Adults: A Cross-Sectional Study.

The long-term effects of secondhand smoke (SHS) on dental caries among Japanese young adults remain unclear. The purpose of this cross-sectional study was to evaluate whether household exposure to SHS is associated with dental caries in permanent dentition among Japanese young adults. The study sample included 1905 first-year university students (age range: 18-19 years) who answered a questionnaire and participated in oral examinations. The degree of household exposure to SHS was categorized into four levels according to the SHS duration: no experience (-), past, current SHS < 10 years, and current SHS ≥ 10 years. Dental caries are expressed as the total number of decayed, missing, and filled teeth (DMFT) score. The relationships between SHS and dental caries were determined by logistic regression analysis. DMFT scores (median (25th percentile, 75th percentile)) were significantly higher in the current SHS ≥ 10 years (median: 1.0 (0.0, 3.0)) than in the SHS-(median: 0.0 (0.0, 2.0)); p = 0.001). DMFT ≥ 1 was significantly associated with SHS ≥ 10 years (adjusted odds ratio: 1.50, 95% confidence interval: 1.20-1.87, p < 0.001). Long-term exposure to SHS (≥10 years) was associated with dental caries in permanent dentition among Japanese young adults.

Associations between sleep bruxism, sleep quality, and exposure to secondhand smoke in Japanese young adults: a cross-sectional study.

OBJECTIVE: Sleep bruxism, a major sleep disorder that causes serious harm to oral health, is considered a multifactorial disease. Sleep bruxism can be induced by smoking, which also adversely affects sleep quality. The objective of present study was to clarify the associations between sleep bruxism, sleep quality, and exposure to secondhand smoke (SHS). METHODS: To assess the prevalence of sleep bruxism, sleep quality, and SHS exposure, we conducted oral examinations and self-report questionnaires on university students in Japan. Sleep bruxism and quality were screened using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI) and the third edition of the International Classification of Sleep Disorders (ICSD-3). The inclusion criteria were adults aged between 18 and 19 years, non-smokers and non-alcohol drinkers. The exclusion criteria was failing to complete the questionnaire in full. RESULTS: We analyzed a total of 1781 Japanese young adults. Young adult females who had been exposed to SHS had worse sleep quality (p = 0.019) than those who had not. Young adult female with worse sleep quality showed a higher prevalence of sleep bruxism (p = 0.034) than those with better sleep quality. Using structural equation modeling, direct associations were identified between SHS exposure and poor sleep quality (standardized coefficients, 0.153; p = 0.008) and between sleep bruxism and poor sleep quality (standardized coefficients, 0.187; p = 0.022) in young adult females. However, no association was found among young adult males. CONCLUSION: SHS exposure is indirectly associated with sleep bruxism through poor sleep quality in Japanese young adult females.

Influence of Occupational Stress and Coping Style on Periodontitis among Japanese Workers: A Cross-Sectional Study.

The aim of this cross-sectional study was to evaluate the association between the influence of occupational stress and coping style on periodontitis among Japanese workers. The study sample included 738 workers (age range: 19-65 years) at a manufacturing company in Kagawa Prefecture, Japan. To analyze occupational stress and coping style, all participants answered a self-report questionnaire composed of items on their work environment and oral health behavior. Oral examinations were performed by calibrated dentists. Among all workers, 492 (66.7%) workers were diagnosed with periodontitis, and 50 (6.8%) were diagnosed with a high stress-low coping condition. Significant differences (p < 0.05) were observed between the periodontitis and non-periodontitis groups in terms of age, gender, body mass index, smoking status, daily alcohol drinking, monthly overtime work, worker type, and stress-coping style. Logistic regression analysis showed that a high stress-low coping condition was associated with an increased risk of periodontitis (odds ratio: 2.79, 95% confidence interval: 1.05-7.43, p = 0.039). These findings suggest that a high stress-low coping condition is associated with periodontitis among the 19-65 years of age group of Japanese workers.

Association between periodontitis and prognosis of pancreatobiliary tract cancer: A pilot study.

Several studies have indicated that periodontitis is a risk factor for cancer. However, the association between periodontitis and the prognosis of pancreatobiliary tract cancer remains unclear. The aim of this pilot study was to investigate the association between periodontitis and prognosis of pancreatobiliary tract cancer. A total of 22 patients diagnosed with pancreatobiliary tract cancer were analyzed. Oral health status, including severity of periodontitis, general health status and biochemical serum markers were evaluated. The Kaplan-Meier method and Cox proportional hazards model were used to assess factors affecting the prognosis of pancreatobiliary tract cancer. The Kaplan-Meier analysis demonstrated that low body mass index, high concentration of serum C-reactive protein (CRP) and severe periodontitis were significant prognostic factors for survival rate. The Cox proportional hazards model revealed that serum carbohydrate antigen 19-9 concentration [hazard ratio (HR)=1.002; 95% confidence interval (CI): 1.000-1.004] and serum CRP concentration (HR=2.57; 95% CI: 1.15-5.74) were significantly associated with the prognosis of pancreatobiliary tract cancer. In addition, cancer patients with severe periodontitis had higher serum CRP concentrations compared with those without severe periodontitis. Therefore, severe periodontitis indirectly affected the prognosis of pancreatobiliary tract cancer through promoting systemic inflammation.

miR­1246 and miR­4644 in salivary exosome as potential biomarkers for pancreatobiliary tract cancer.

Pancreatobiliary tract cancer is a highly fatal cancer. Detection of pancreatobiliary tract cancer is difficult because it lacks typical clinical symptoms and because of its anatomical location. Biomarker discovery is therefore important to detect pancreatobiliary tract cancer in its early stage. A study demonstrated that expression levels of miR­1246, miR­3976, miR­4306, and miR­4644 in serum exosomes were higher in pancreatic cancer patients than these levels in healthy control participants. Supposing that microRNA (miRNA) expression profiles in saliva are similar to those in serum, four miRNAs (miR­1246, miR­3976, miR­4306, and miR­4644) in salivary exosomes may also be useful for detection of pancreatobiliary tract cancer. In this study, it was examined whether these miRNAs could be used as biomarkers for pancreatobiliary tract cancer. Twelve pancreatobiliary tract cancer patients and 13 healthy control participants were analyzed as a cancer and a control group, respectively. Unstimulated whole saliva was collected, salivary exosomes were isolated, and total RNA was extracted. Using quantitative real­time PCR (RT­qPCR), the relative expression ratios of miR­1246 and miR­4644 were significantly higher in the cancer group than these ratios in the control group. Receiver operating characteristic (ROC) curves were constructed to analyze the discrimination power of these miRNAs. For miR­1246, the results yielded an area under the curve (AUC) of 0.814 (P=0.008). For miR­4644, the results yielded an AUC of 0.763 (P=0.026). For the combination of miR­1246 and miR­4644, the results yielded an increased AUC of 0.833 (P=0.005). This pilot study suggests that miR­1246 and miR­4644 in salivary exosomes could be candidate biomarkers for pancreatobiliary tract cancer.

Application of coenzyme Q10 for accelerating soft tissue wound healing after tooth extraction in rats.

Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10), may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old) (n = 27) received topical application of ointment containing 5% rCoQ10 (experimental group) or control ointment (control group) to the sockets for 3 or 8 days (n = 6-7/group). At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p < 0.05). Gene expression of interleukin-1ß, tumor necrosis factor-α and nuclear factor-κB were also lower in the experimental group than in the control group (p < 0.05). At 8 days after tooth extraction, there were no significant differences in collagen density, number of polymorphonuclear leukocytes and bone fill between the groups. Our results suggest that topical application of rCoQ10 promotes wound healing in the soft tissue of the alveolar socket, but that rCoQ10 has a limited effect on bone remodeling in rats.

Occlusal disharmony accelerates the initiation of atherosclerosis in apoE knockout rats.

BACKGROUND: Psychosocial stress is one of the risk factors for atherosclerosis. As occlusal disharmony induces psychological stress, we hypothesized that psychological stress by occlusal disharmony accelerates atherosclerosis. The aim of this study was to investigate the effects of occlusal disharmony on the initiation of atherosclerosis in apolipoprotein E (apoE) knockout rats. METHODS: Fourteen male apoE-knockout rats (age; 8 weeks) (Sprague-Dawley strain background) were divided into two groups of seven rats: the occlusal disharmony group and the no treatment (control) group. In the occlusal disharmony group, the maxillary molar cusps were cut off for the 8-week experimental period. RESULTS: In the occlusal disharmony group, the percentages of the area of total aortic lumen occupied by plaques and lipid were significantly higher than those in the control group (p < 0.05, t-test). The occlusal disharmony group also showed significantly higher serum levels of very low-density lipoprotein-cholesterol (VLDL) and low-density lipoprotein-cholesterol (LDL), plasma levels of corticosterone (1.9, 1.3 and 1.3 times, respectively), higher aortic protein expression levels of vascular cell adhesion molecule-1 (VCAM1) and intercellular adhesion molecule-1 (ICAM1) (1.5 and 1.4 times, respectively), and higher aortic gene expression of levels of VCAM1 and Toll-like receptor 4 (TLR4) (1.9 and 4.3 times, respectively), as compared to the control group (p < 0.05). However, there were no significant differences in serum levels of oxidized LDL, reactive oxygen metabolites and C-reactive protein between the two groups. CONCLUSION: In apoE knockout rats, occlusal disharmony may induce VCAM1, ICAM1 and TLR4 expression and accelerate the initiation of atherosclerosis.

Relationship between increases in BMI and changes in periodontal status: a prospective cohort study.

AIM: The purpose of this prospective cohort study was to investigate whether body mass index (BMI) and oral health behaviour are related to changes in periodontal status in Japanese university students. MATERIALS AND METHODS: Students (n = 224) who were interested in receiving oral health examinations before entering university and before graduation were included in the analysis. Subjects were investigated regarding the correlations of oral health behaviours and increases in BMI with the percentage of bleeding on probing (%BOP) and Community Periodontal Index (CPI) scores as indicators of changes in periodontal status. RESULTS: The risk of increased %BOP was associated with the non-use of dental floss (adjusted odds ratio [OR]: 3.11; 95% confidence interval [CI]: 1.31-7.37; p < 0.05), whereas the risk of increased CPI score was associated with increases in BMI (OR: 1.95; 95% CI: 1.05-3.65; p < 0.05) and simplified oral hygiene index score (OR: 2.28; 95% CI: 1.23-4.22; p < 0.01). CONCLUSION: Increases in BMI were associated with worsening of periodontal status, defined as increased CPI score in Japanese university students, whereas lack of inter-dental cleaning was associated with exacerbated gingival bleeding.

Involvement of toll-like receptor 2 and 4 in association between dyslipidemia and osteoclast differentiation in apolipoprotein E deficient rat periodontium.

BACKGROUND: Dyslipidemia increases circulating levels of oxidized low-density lipoprotein (OxLDL) and this may induce alveolar bone loss through toll-like receptor (TLR) 2 and 4. The purpose of this study was to investigate the effects of dyslipidemia on osteoclast differentiation associated with TLR2 and TLR4 in periodontal tissues using a rat dyslipidemia (apolipoprotein E deficient) model. METHODS: Levels of plasma OxLDL, and the cholesterol and phospholipid profiles in plasma lipoproteins were compared between apolipoprotein E-deficient rats (16-week-old males) and wild-type (control) rats. In the periodontal tissue, we evaluated the changes in TLR2, TLR4, receptor activator of nuclear factor kappa B ligand (RANKL) and tartrate resistant acid phosphatase (TRAP) expression. RESULTS: Apolipoprotein E-deficient rats showed higher plasma levels of OxLDL than control rats (p<0.05), with higher plasma levels of total cholesterol (p<0.05) and LDL-cholesterol (p<0.05) and lower plasma levels of high-density lipoprotein cholesterol (p<0.05). Their periodontal tissue also exhibited a higher ratio of RANKL-positive cells and a higher number of TRAP-positive osteoclasts than control rats (p<0.05). Furthermore, periodontal gene expression of TLR2, TLR4 and RANKL was higher in apolipoprotein E-deficient rats than in control rats (p<0.05). CONCLUSION: These findings underscore the important role for TLR2 and TLR4 in mediating the osteoclast differentiation on alveolar bone response to dyslipidemia.