Oral Health Status of Workers in Acid Exposure Environments in Japan: A Cross-sectional Study.

Although the working environment may play a role in dental acid erosion, few studies have been conducted on this in Japanese workers in recent years. The purpose of this study was to investigate oral health status, including dental erosion, in workers who may have been exposed to an acidic environment. The study participants were recruited by an online research company. Oral examinations and questionnaire surveys were conducted on this cohort in January 2023. A total of 144 participants were finally included. Workers exposed to an acidic environment showed more use of protective equipment and underwent more dental examinations at the workplace (p<0.001). Possible dental erosion was observed in only 3 out of the total of 144 participants (2.1%), however. No significant difference was observed in the number of teeth, caries experience, or dental erosion according to the number of years of acid exposure in the workplace. The results of this study suggest that acid exposure exerts a relatively small effect on the oral health status of workers in Japan.

Inhibition of Citric Acid-Induced Dentin Erosion by an Acidulated Phosphate Sodium Monofluorophosphate Solution.

Sodium monofluorophosphate (Na2FPO3, MFP) is mainly used as an ingredient in fluoride-based dentifrices as it has a high safety profile, with one-third of the toxicity of sodium fluoride (NaF), as well as the ability to reach deep into the dentin. The purpose of this study was to assess the prevention of dentin erosion by MFP upon exposure to citric acid, which has a chelating effect, and to compare the effects to those of the conventional acidulated phosphate fluoride (APF) application method. Bovine dentin was used, and four groups were created: (i) APF (9000 ppmF, pH 3.6) 4 min group; (ii) acidulated phosphate MFP (AP-MFP, 9000 ppmF, pH 3.6) 4 min group; (iii) AP-MFP 2 min + APF 2 min (dual) group; and (iv) no fluoride application (control) group. Compared with the conventional APF application method, the application of AP-MFP was shown to significantly reduce substantial defects, mineral loss, and lesion depth; better maintain Vickers hardness; and promote the homogenous aggregation of fine CaF2 particles to seal the dentin tubules, enhancing acid resistance in their vicinity. The ΔZ value of the AP-MFP group was 2679 ± 290.2 vol% µm, significantly smaller than the APF group's 3806 ± 257.5 vol% µm (p < 0.01). Thus, AP-MFP-based fluoride application could effectively suppress citric acid-induced demineralization and could become a new, more powerful, and biologically safer professional-care method for preventing acid-induced dentin erosion than the conventional method.

Improved Enamel Acid Resistance Using Biocompatible Nano-Hydroxyapatite Coating Method.

In this study, we attempted to develop a dental caries prevention method using a bioapatite (BioHap), an eggshell-derived apatite with nanoparticle size and biocompatibility, with a high-concentration fluoride tooth surface application method. The enamel acid resistance after the application of the proposed method was compared with that of a conventional topical application of fluoride using bovine tooth enamel as an example. The tooth samples were divided into three groups based on the preventive treatment applied, and an acid challenge was performed. The samples were evaluated for acid resistance using qualitative and quantitative analytical methods. The BioHap group demonstrated reduced enamel loss and improved micro-Vickers hardness, along with a thick coating layer, decreased reaction area depth, and decreased mineral loss value and lesion depth. The combination of BioHap with high-concentration fluoride led to the formation of a thick coating layer on the enamel surface and better suppression of demineralization than the conventional method, both qualitatively and quantitatively. The proposed biocompatible nano-hydroxyapatite coating method is expected to become a new standard for providing professional care to prevent dental caries.

Improved Enamel Acid Resistance by Highly Concentrated Acidulated Phosphate Sodium Monofluorophosphate Solution.

Sodium monofluorophosphate (MFP) is a component of fluoride-containing dentifrices and is more biosafe than the conventional sodium fluoride (NaF). MFP can respond not only on the tooth surface layer but also deep into the enamel. We aim to confirm that high concentrations of acid phosphate MFP (AP-MFP, 9000 ppmF), used in professional care, could lead to a highly biosafe fluoride application method that acts through the deep enamel layers. Sample groups were respectively treated in vitro with NaF, acidulated phosphate fluoride (APF), MFP, and AP-MFP, and the samples were compared against an untreated group. Characterizations after fluoride application confirmed that MFP and AP-MFP treatments improved the acid resistance of enamel compared to that of conventional methods. Furthermore, the acid resistance of highly concentrated MFPs improved by using phosphoric acid. Although the acid resistance from the AP-MFP method is not as good as that using APF, AP-MFP can act both on the surface layer and deep into the enamel. Moreover, AP-MFP retains fluoride ions as much as APF does on the tooth surface. The proposed fluoride application method using AP-MFP introduces a dental treatment for acid resistance that is highly biosafe and penetrates deep layers of the enamel.

COVID-19-Related Factors Delaying Dental Visits of Workers in Japan.

BACKGROUND: The aim of this research was to investigate the factors associated with postponing dental attendance amongst Japanese workers during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: We conducted an internet-based survey in Japan from November 24 to 29, 2021. The participants were selected from people registered with an online research company. The inclusion criteria for this study were full-time or part-time workers aged 20 to 69 years. Participants filled out a questionnaire about their oral health, behaviour, and working conditions. RESULTS: A total of 1840 participants were included in the analysis. Three hundred ninety-eight participants (21.5%) answered that they postponed dental attendance due to COVID-19. Multiple logistic regression showed that women were more likely to postpone dental attendance (odds ratio [OR], 1.74; 95% confidence interval, 1.33-2.26). Moreover, employment status, household income, changes in income, working at home, interdental cleaning device use, regular dental attendance, awareness of untreated teeth, and dental pain were also associated with postponing dental attendance. The results of decision tree analysis showed that regular dental attenders with dental pain were the most likely to postpone dental attendance. CONCLUSIONS: The characteristics of postponed dental visits for Japanese workers differ depending on whether one is a regular dental attender or not. Amongst regular dental attenders, worsening oral health due to interruptions in dental attendance is concerning. Meanwhile, untreated teeth might be neglected amongst nonregular dental attenders. Preventing patients from refraining from dental attendance, regardless of whether or not they are regular dental attenders, is important during the COVID-19 pandemic.

Reasons for Tooth Extractions in Japan: The Second Nationwide Survey.

BACKGROUND: More than 10 years have passed since the first nationwide study on the reasons for tooth extraction in Japan. In the present study, we conducted the second nationwide survey to update the previous data. METHODS: This was a descriptive study. A sample population consisting of 5,250 dentists was selected by systematic random sampling using the 2018 membership directory of the Japan Dental Association. The reason for each permanent tooth extraction was documented by each dentist during a period of 1 week from June 4 to June 10, 2018. A questionnaire was provided for documentation. Reasons for tooth extraction were categorised into 6 groups as follows: caries, periodontal disease, fracture, orthodontics, impacted teeth, and others. RESULTS: A total of 2345 identified dentists responded to the questionnaire (recovery rate: 44.8%). Information on 7809 extracted teeth from 6398 patients was obtained. Periodontal disease was the main reason for tooth extraction for both sexes (men: 40.4%, women: 34.9%). Caries accounted for 30.2% of tooth extractions among men and 29.0% among women. Periodontal disease was predominant in the groups older than 55 years of age. Dental fracture accounted for 16.8% of tooth extractions among men and 19.2% among women. CONCLUSIONS: Caries and periodontal disease are still the main reasons for tooth extraction in Japan. Moreover, dentists should note that fractures accounted for approximately one-fifth of permanent tooth extractions after the age of 45 years.

A Validation Study of the National Database of Health Insurance Claims and Specific Health Checkups of Japan Regarding the Annual Number of Tooth Extractions Performed Across the Entire Japanese Population.

This report describes a validation study of data in the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) obtained by nationwide surveys on tooth extractions. The following 3 data sources on tooth extractions in Japan were compared: (1) the Nationwide Survey of the Reasons for Permanent Tooth Extractions in Japan (a previous survey conducted by the present authors); (2) the Statistics on Medical Care Activities in Public Health Insurance; and (3) the 4th NDB Open Data Japan. Source 1 was a nationwide survey conducted in 2018; sources 2 and 3 comprised data that are freely available for use by the public. In Source 1, 2,345 of 5,250 dentists approached responded to the questionnaire (recovery rate: 44.8%). The number of extracted teeth among younger age groups (aged 25-50 years) reported in Source 1 was lower than that in the other two sources. In contrast, the number of extracted teeth among older age groups reported in Source 1 was higher than that reported in the other two sources. However, when stratified by age group, all differences across the 3 sources regarding the mean annual number of tooth extractions were <0.05 teeth/year. The present results suggest that the NDB is a reliable resource for data on tooth extractions performed across the entire Japanese population.

Self-Reported Diabetes Mellitus and Tooth Extraction Due to Periodontal Disease and Dental Caries in the Japanese Population.

Diabetes mellitus is closely related to oral health. We aimed to determine the relationship between diabetes mellitus and tooth extraction due to periodontal disease and dental caries. Japan's second nationwide survey data collected from 4 June to 10 June 2018 was used to identify reasons for tooth extraction among patients aged > 40 years. General dentists collected information on patients who underwent tooth extraction procedures, and the presence of diabetes mellitus was determined through interviews. Multivariable logistic regression was performed to investigate the relationship between diabetes mellitus and the reasons for tooth extraction, including periodontal disease and dental caries. In total, 2345 dentists responded to the survey (response rate 44.8%). We analyzed data on 4625 extracted teeth from 3750 patients (1815 males and 1935 females). Among patients with self-reported diabetes mellitus, 55.4% had extractions due to periodontal disease compared to 46.7% of such extractions among those without self-reported diabetes mellitus. Self-reported diabetes mellitus was significantly associated with tooth extraction due to periodontal disease. No significant differences were observed in dental caries according to self-reported diabetes mellitus status. This study provides further evidence of a significant association between diabetes mellitus and tooth extraction due to periodontal disease.

Evaluation of Public Health Expenditure by Number of Teeth among Outpatients with Diabetes Mellitus.

The relationship between public health expenditure and number of teeth was investigated in patients with diabetes mellitus using data obtained from the Japanese National Database of Health Insurance Claims and Specific Health Checkups. Data on medical, dental, and pharmacy claims generated between April 2015 and March 2016 were analyzed in patients with diabetes mellitus aged 50-74 years who used outpatient services during this period. Patients initiating medical and pharmacy claims related to diabetes mellitus were defined as having diabetes mellitus. Number of teeth was defined as number of teeth in conjunction with periodontitis due to the nature of the data source. Descriptive statistics were used to investigate the association between number of teeth and public health expenditure. Data on a total of 1,017,758 patients with diabetes mellitus were analyzed. Patients with the fewest teeth incurred higher medical expenses. The largest mean difference in medical expenditure was observed between patients with 5-9 teeth and those with over 28 teeth. The results of this study suggest that public health expenditure on patients with diabetes mellitus differs based on number of teeth.

Relationship between Obesity Indicators and Gingival Inflammation in Middle-aged Japanese Men.

The purpose of this study was to investigate the relationship among the waist-to-height ratio (WHtR) and the body mass index (BMI) as obesity indicators and gingival inflammation as determined by bleeding on probing (BOP). The participants comprised employees of a milk products company based in Tokyo, Japan. A total of 159 non-diabetic men aged 40 to 59 yr and with a minimum of 28 teeth were included. Multiple logistic regression analysis controlling for age, smoking status, pocket depth, frequency of daily brushing, frequency of weekly interdental brushing, and regular dental attendance was performed to compare the relationships among the obesity indicators and BOP. Participants with good oral hygiene had significantly less BOP than those with poor oral hygiene (p<0.001). No significant differences were observed among the other items investigated. A significant association was observed between WHtR and BOP (odds ratio: 2.40, 95% confidence interval: 1.11-5.22); no such association was observed with the BMI, however. The present results showed that obesity, as determined according to a visceral fat index, was associated with BOP, but not with BMI. This suggests that the WHtR is a more accurate index of obesity than the BMI in studies on BOP.

Factors associated with development of root caries in dentition without root caries experience in a 2-year cohort study in Japan.

OBJECTIVES: To investigate factors associated with the development of root caries in dentition without root caries experience and interactive relationships between risk factors. METHODS: We conducted surveys, consisting of an oral examination (oral hygiene, assessment of the number of teeth, coronal and root caries) and a self-reported questionnaire, among employees of a company in Tokyo, Japan in 2016 and 2018. Questionnaires collected data on smoking status, oral hygiene habits, sugar intake, and frequency of dental visits. Multiple logistic regression and decision tree analyses were used to determine factors associated with the development of root caries. RESULTS: A total of 299 participants aged 25-63 years were included in the analysis. Males, older adults, smokers/past smokers had a significantly greater risk of developing root caries. The risk of developing root caries was significantly associated with the number of teeth with gingival recession at baseline (6-9 teeth, odds ratio [OR]: 7.69, 95 % confidence interval [CI]: 2.31-25.56; 10+ teeth, OR: 9.19, 95 % CI: 2.73-30.95, relative to ≤5 teeth); and with the number of coronal decayed and filled (DF) teeth (11-13 teeth, OR: 3.21, 95 % CI: 1.12-9.24; and ≥14 teeth, OR: 3.60, 95 % CI: 1.27-10.20, relative to ≤10 teeth). Other factors associated with root caries development differed according to the number of teeth with gingival recession and included drinking sugar-sweetened beverages, and the amount of toothpaste used. CONCLUSIONS: Gingival recession and number of coronal DF teeth were associated with the development of root caries. CLINICAL SIGNIFICANCE: Multiple factors are associated with root caries development. The effect of risk factors such as drinking sweetened beverages and less toothpaste use is greater in individuals with greater gingival recession and more coronal decayed and filled teeth. Dental practitioners should focus on modifiable risk factors to prevent root caries.

Evaluation of tooth loss among patients with diabetes mellitus using the National Database of Health Insurance Claims and Specific Health Checkups of Japan.

BACKGROUND: Although diabetes mellitus is reported to be related to tooth loss, there is limited population-based evidence for this relationship. We investigated the actual situation of tooth loss by performing a population-based survey using information obtained from the National Database of Health Insurance Claims and Specific Health Checkups (NDB) in Japan. METHODS: Medical, dental and pharmacy claims data generated between 1 April 2015 and 31 March 2016 were obtained and analysed. Patients with medical and pharmacy claims of diabetes mellitus were allocated to the diabetes mellitus group. Patients with medical claims of acute upper respiratory inflammation, but without claims of diabetes mellitus, were allocated to the control group. The number of claims involving tooth loss, treatment of periodontal disease and visits to medical and dental institutions were obtained from the NDB. Descriptive statistics were used to compare the nature of tooth loss between patients with diabetes mellitus and the control groups. RESULTS: There were 5,248,405 patients in the control group and 1,570,082 patients in the diabetes mellitus group. Patients in the diabetes mellitus group showed a higher level of tooth loss than patients in the control group, among both sexes. Patients with diabetes mellitus tended to lose their posterior teeth at an earlier age than patients in the control group. Moreover, patients in the diabetes mellitus group showed greater tooth loss, regardless of whether or not periodontal disease was treated. CONCLUSION: Patients with diabetes mellitus show a higher level of tooth loss than those without diabetes mellitus, based on the results of a population-based survey.

Factors Associated with Untreated Decayed Teeth in Male Sales Workers: An Internet Survey.

The purpose of this study was to identify factors associated with untreated decayed teeth (DT) in male sales workers. The participants were recruited by screening a pool of Japanese registrants in an online database for eligibility for inclusion in the study. Between 20 February 2015 and 11 March 2015, those deemed eligible were asked to complete a questionnaire on the status of their oral health. Responses from a total of 142 male sales workers aged between 30 and 49 years were analyzed. Of these, 40 reported DT and 102 no untreated decayed teeth (NDT). The percentage of participants with DT was higher than that with NDT among night shift workers (p<0.001). A higher percentage of participants with DT reported pain when eating or drinking something cold (p=0.041), pain in the teeth or gingiva (p<0.001), or frequent stomatitis (p=0.030). A higher percentage of participants with DT reported eating between meals (p=0.027) and a lower percentage visiting a dental clinic in the past 6 months (p=0.017) compared with among participants with NDT. Those with NDT were more likely to report an inability to visit a dental clinic when they wanted to (p=0.033), but those with DT were more likely to report that their reasons for not visiting a dental clinic were that multiple visits were required for treatment (p=0.012) or that they did not like the treatment (p=0.005). Working the night shift (Odds Ratio [OR], 3.492; 95% Confidence Interval [CI], 1.347-8.725) and visiting a dental clinic in the past 6 months (OR, 0.084; 95%CI, 0.010-0.733) were identified as independent variables correlated with leaving DT untreated. Requiring oral health education and dental checkups at least once every 6 months may have a positive effect on oral health among male sales workers, especially those doing night shifts.

Relationship between Blood HbA1c Level and Decayed Teeth in Patients with Type 2 Diabetes: A Cross-sectional Study.

The purpose of this cross-sectional study was to determine whether there is an association between hemoglobin A1c (HbA1c) level and the presence or absence of decayed teeth in patients with type 2 diabetes mellitus. The patients and data on their age and sex, the presence or absence of dental claims, medical history of diabetes mellitus, and workplace dental examinations were obtained from a Japanese healthcare database available for epidemiological studies. The HbA1c levels were obtained from results of the Specific Health Checkups and Specific Health Guidance tests conducted by the Japanese Ministry of Health, Labour and Welfare. Data on a total of 1,897 patients were analyzed. Patients with poorly controlled diabetes (HbA1c≥6.5, n=779) had more decayed teeth than those in whom it was well controlled (HbA1c<6.5, n=1,118). Multiple logistic regression analysis with the presence or absence of decayed teeth as a dependent variable revealed a significant association between an HbA1c level of ≥8.0 and decayed teeth (odds ratio: 1.69; 95% confidence interval, 1.24-2.29), even after adjusting for dental attendance. This suggests that a poorly controlled blood HbA1c level is a risk factor for dental caries. More thorough oral hygiene instruction and education on preventive treatment for dental caries in patients with poorly controlled diabetes are needed.

Number of Non-vital Teeth as Indicator of Tooth Loss during 10-year Maintenance: A Retrospective Study.

The purpose of this study was to investigate whether number of non-vital teeth was an indicator of tooth loss during maintenance. Thirty-three general practitioners provided data on 321 patients undergoing maintenance over 10 years. The number of present teeth (PT), smoking status, level of bone loss, number of non-vital teeth, and reason for tooth loss during that period were investigated. Multiple logistic regression was performed to identify whether the number of non-vital teeth was associated with tooth loss. The average number of lost teeth was 1.07±1.82; that of PT at baseline was 24.4±3.9; and that of non-vital teeth at baseline was 5.4±4.5. Multiple logistic regression revealed a significant association between >8 non-vital teeth and tooth loss during maintenance (odds ratio [OR]: 2.40; 95% confidence interval [CI]: 1.18-4.87). It also demonstrated relationships between >8 non-vital teeth and root fracture or caries (OR: 3.90; 95%CI: 1.68-9.03 or OR: 2.85, 95%CI: 1.14-7.10, respectively). The number of non-vital teeth was associated with tooth loss during maintenance. The results suggest that patients with many non-vital teeth before commencement of maintenance are particularly at risk of tooth loss due to root fracture or caries. Therefore, the number of non-vital teeth offers a useful indicator of potential tooth loss.

Working Environment Factors Associated with Regular Dental Attendance.

The aim of this study was to identify factors in the working environment associated with regular dental attendance. Thirty-three general practitioners provided data on 488 patients who underwent dental maintenance between 2003 and 2015. The age of the patients ranged from 40 to 65 years. Appointment adherence, employment format, overtime work, night work, and subjective evaluation of work were investigated. Multiple logistic regression analysis was performed to identify factors associated with regular dental attendance. Among all participants, 296 (60.7%) were female, 320 (65.6%) worked full-time, 193 (39.5%) worked overtime, and 34 (7.0%) worked nights. The results of the analysis revealed that only night work was a significant factor after adjusting for sex, age, and employment format (odds ratio, 0.220; 95% confidence interval, 0.088-0.550). The results of this study suggest that night work disturbs regular dental attendance.

Relationship between Obstructive Sleep Apnea and Self-assessed Oral Health Status: An Internet Survey.

The purpose of this study based on a cross-sectional internet survey was to investigate the relationship between risk of obstructive sleep apnea (OSA) and self-assessed oral health status. The participants, who comprised individuals registered with an online research company, were required to complete a self-reported questionnaire. Those answering in the affirmative to both of the following two questions were placed in the OSA-risk group, while those answering in the negative were assigned to the control group: 'Have other people noticed pauses in your breathing while you are sleeping?' and 'Do you feel excessively sleepy during the daytime?'. A total of 493 were included in the OSA-risk group and 2,560 in the control group. Among the total 3,053 respondents, the highest prevalence for OSA risk in men was in the 50-59-year age range, although this tended to level off after age 60 years. No such trend was observed in women, however. Multiple logistic regression analysis was performed to identify the relationship between risk of OSA and self-assessed oral health status. Significant correlations were observed with the following parameters: difficulty in opening mouth (odds ratio [OR]: 2.66; 95% confidence interval [CI]: 1.647-4.311), dry mouth (OR: 2.11; CI: 1.544-2.876), bad breath (OR: 1.69; CI: 1.309-2.186), gingival bleeding (OR: 1.48; CI: 1.134-1.932), and gingival swelling (OR: 1.44; CI: 1.046-1.981). These results suggest a relationship between risk of OSA and self-assessed oral health status, indicating that treating OSA might improve oral health status. Further study is needed to demonstrate a causal relationship between OSA and self-assessed oral health status, however.

Comparison of risk factors for tooth loss between professional drivers and white-collar workers: an internet survey.

This cross-sectional study was conducted to examine tooth loss and associated factors among professional drivers and white-collar workers. The participants were recruited by applying screening procedures to a pool of Japanese registrants in an online database. The participants were asked to complete a self-reported questionnaire. A total of 592 professional drivers and 328 white-collar workers (male, aged 30 to 69 years) were analyzed. A multiple logistic regression analysis was performed to identify differences between professional drivers and white-collar workers. The results showed that professional drivers had fewer teeth than white-collar workers (odds ratio [OR], 1.74; 95% confidence interval [95% CI], 1.150-2.625). Moreover, a second multiple logistic regression analysis revealed that several factors were associated with the number of teeth among professional drivers: diabetes mellitus (OR, 2.68; 95% CI, 1.388-5.173), duration of brushing teeth (OR, 1.66; 95% CI, 1.066-2.572), frequency of eating breakfast (OR, 2.23; 95% CI, 1.416-3.513), frequency of eating out (OR, 1.70; 95% CI, 1.086-2.671) and smoking status (OR, 2.88; 95% CI, 1.388-5.964). These findings suggest that the lifestyles of professional drivers could be related to not only their general health status, but also tooth loss.