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.

Survival Rate of 3-unit Fixed Partial Dentures Replacing First Molars: A Retrospective Cohort Study.

Fixed partial dentures (FPDs) made of 12% Au-Pd alloy are covered under Japan's national health insurance system. The survival rate of such 3-unit fixed FPDs remains unknown, however. The purpose of this retrospective study was to assess their survival rate in the replacement of first molars. A total of 140 FPDs were included, and the endpoint was removal of an FPD. During the observation period, 43 FPDs were removed. The FPD survival rate was 70.2% at 10 yr, 58.2% at 15 yr, and 42.1% at 20 yr according to the Kaplan-Meier method. The estimated mean survival period was 19.4 yr. The main reasons for FPD loss were dental caries (27.9%), separation from the abutment tooth (18.6%), and pulpitis (18.6%). Single factor analysis using the log-rank test showed that two factors influenced FPD survival: a smaller gonial angle and deep pockets around the abutment teeth. This effect was not statistically significant in either case, however (p>0.05). The present results suggest that the prevention of caries and of the separation of the dentures from the abutment teeth are important factors in the long-term survival of FPDs.

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.

Survival Rate of Removable Partial Dentures with Mandibular Bilateral Free End Saddle: A Retrospective Study.

The purpose of this study was to investigate the survival of removable partial dentures with a mandibular bilateral free end saddle (BFES) and abutment teeth in a clinical setting. Only mandibular dentures with a BFES were included (10 or fewer present teeth, and fewer than 4 occlusal units). The endpoints were replacement of denture and loss of abutment teeth. A total of 128 dentures and 595 abutment teeth were analyzed. Nineteen dentures had to be replaced during the observation period (mean duration: 11.4±6.9 years; range: 3 to 36 years). According to Kaplan-Meier analysis, the survival rate was 93.2% at 10 years and 68.6% at 20 years. The estimated mean survival period was 27.8 years. Single-factor analysis using the log-rank test showed that no factor investigated had a significant influence. The main reason for denture replacement was loss of abutment teeth (47.4%). The survival rate of the abutment teeth was 91.3% at 10 years and 77.3% at 20 years. The analysis revealed 4 significant risk factors: male sex (hazard ratio [HR]: 1.78); premolars (HR: 1.67); a lower number of abutment teeth (HR: 3.24); and history of endodontic treatment (HR: 2.79). The removable partial dentures with a mandibular BFES in this study lasted over 20 years, and their survival was influenced by loss of abutment teeth. Dentures are used continuously over long periods of time and should therefore be designed to allow easy adjustment when abutment teeth are lost.

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.

Survival rate of removable partial dentures with complete arch reconstruction using double crowns: a retrospective study.

OBJECTIVES: The purpose of this study was to clinically investigate double-crown-retained removable partial dentures (DRPDs) and abutment teeth at dental clinics. MATERIALS AND METHODS: Only cases with complete arch reconstruction were included. Endpoints were replacement of denture and loss of abutment tooth. A total of 213 dentures with 1030 abutment teeth were analyzed. RESULTS: During the observation period, 32 dentures were replaced. The mean observation period was 12.7 (± 6.6) years (range 3 to 36). By the Kaplan-Meier method, survival rate at 10 years was 94.7% and at 20 years was 70.8%. Estimated mean survival period was 27.1 years. Cox regression analysis showed that risk factor for replacement was good occlusion as indicated by Eichner index groups A to B3 (HR 2.81). The main reason for denture replacement was loss of abutment teeth. Survival rate of abutment teeth at 10 years was 83.8% and at 20 years was 66.3%. The analysis revealed six risk factors: male gender (HR 1.76), age range 65-89 years (HR 1.51), posterior teeth (HR 1.60), higher number of present teeth in opposite jaw (HR 1.69), lower number of abutment teeth (HR 1.76), and short inner crown (HR 2.28). CONCLUSION: DRPDs last over 20 years, making them a durable investment in one's oral health; their survival is influenced by loss of abutment teeth. CLINICAL RELEVANCE: In cases where there are few teeth remaining in a jaw, DRPDs represent a suitable treatment that makes use of the remaining teeth, even if the abutment teeth are non-vital.

Relationship between oral symptoms during diving work and preventative dental visits in Japanese male occupational divers.

This cross-sectional study examined the relationship between dental symptoms experienced by occupational divers during diving and their participation in preventative dental visits. The questionnaire for this study was sent by post to 160 establishments and 215 members of the Japan Diving Association and participants were asked to complete a self-reported questionnaire. Data from 242 occupational divers (male, aged 20-79 yr) were analyzed. Multiple logistic regression analysis and correspondence analysis were performed to determine the relationship between dental symptoms experienced during diving and participation in preventative dental visits. We found that divers who experienced tooth pain while diving had not undergone preventative dental visits within the previous year (odds ratio: 2.76, 95% confidence interval: 1.12-6.80). This was also confirmed by correspondence analysis These findings suggested that not undergoing preventative dental visits was related to tooth pain during diving.

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.

Perceived Body Distortion Rather Than Actual Body Distortion Is Associated With Chronic Low Back Pain in Adults With Cerebral Palsy: A Preliminary Investigation.

OBJECTIVES: The aim of the present study was to investigate whether distorted body perception is a feature of the low back pain (LBP) experience in people with cerebral palsy (CP) and whether any distortions noted are confounded by the presence of motor and postural impairments commonly seen in CP. METHODS: Forty-five individuals participated in this study: 15 adults with CP with LBP (CP_Pain group), 15 adults with CP without LBP (CP_noPain group), and 15 age-matched adults with LBP but no CP (Pain group). Body perception was evaluated using the Fremantle Back Awareness Questionnaire (FreBAQ) and by assessing 2-point discrimination thresholds over the low back. A comprehensive assessment of motor function was also undertaken in the CP population, and postural function was assessed in all 3 groups. RESULTS: Significant differences between the 3 groups were found for FreBAQ scores (P < 0.0001). The TPD threshold in the low back of the CP_Pain group was significantly larger than that of the CP_noPain group (P = 0.01), though we found no difference between the CP_noPain group and the Pain group (P = 0.21). We found no difference in motor or postural function between the 2 CP groups. DISCUSSION: The present results suggest that body image is disrupted in people with CP who experience LBP. The disruptions in perception were similar to those seen in people with LBP and no CP, suggesting that the distortions may be more related to the presence of pain than the presence of CP.