Risk factors for tooth loss in adult Japanese dental patients: 8020 Promotion Foundation Study

Association among the number of natural teeth, dental maintenance visits and diabetes status: a cross-sectional study using employment-based healthcare claims database

Aim

Although diabetes is associated with the risk of tooth loss, there are no large-scale studies examining the reality and the effectiveness of dental maintenance visits in preventing tooth loss. We aimed to investigate the associations among the number of teeth, dental maintenance visits and diabetic status.

Methods

This is a cross-sectional study: a database comprising employment-based health insurance claim and medical check-up data between April 2015 and March 2016. From the dental receipts for a total of 705,542 individuals aged 20-74 years, we calculated dental visits ratio. After excluding missing data on the number of teeth and HbA1c, the association between dental maintenance visits and the number of teeth was further examined in 185,820 individuals aged 40-69 years visited a dentist by diabetes status.

Results

The percentage of dental visits was 46% overall, particularly low among younger subjects (34% in 20 s, 43% in 30 s), and increased with age. The maintenance-included group had a higher number of teeth than the treatment-only group, even at older ages, and this association was observed regardless of diabetes or glycemic control status. Furthermore, even with diabetes, the number of teeth in the group with good glycemic control was like that of non-diabetic.

Conclusion

Dental visits ratio was particularly low among younger subjects and those who receive dental maintenance had a higher number of teeth, regardless of diabetes or not. Adequate glycemic control and dental maintenance were associated with the number of teeth in the people with diabetes. The results suggest that it is important for physicians to work closely with dentists to promote patient-centered care and encourage both maintenance visits and better glycemic control.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-025-00805-1.

The impact of malocclusion on tooth loss over a 20-year period: Findings from the Population-Based Study of Health in Pomerania (SHIP)

OBJECTIVE

Research is lacking examining the effect of malocclusion on tooth loss. The aim of this study was to analyze the possible impact of moderate and severe malocclusions on tooth loss over the course of twenty years.

MATERIAL AND METHODS

Of 1269 subjects aged between 25 and 49 years with at least 20 teeth of the population-based Study of Health in Pomerania in Germany, malocclusions were initially assessed according to a German orthodontic index of treatment priority between 1997 and 2001. The available participants were re-examined every 5 years up to 2021. Tooth loss was analyzed in multilevel survival analyses including tooth, jaw and subject level. The models were adjusted for age, sex, marital status, school education and coexisting malocclusions in the same participant.

RESULTS

Among 623 (49 %) participants with orthodontic treatment priority, 201 showed more than one malocclusion feature. Missing, unreplaced teeth as equivalent for hypodontia, increased overjet of 3-6 mm or > 6 mm, deep bite of > 3 mm with gingival contact, and posterior cusp-to-cusp bite were risk factors for tooth loss. Open bite of 1-2 mm, deep bite of > 3 mm without gingival contact, bilateral crossbite, and incisal crowding with ≤1/2 width of lateral incisor were protective against tooth loss.

CONCLUSIONS

Given the negative and positive impacts of some malocclusions on tooth loss, other potential detrimental effects on oral health and psycho-social well-being were not considered in this study.

CLINICAL SIGNIFICANCE

This long-term study showed for the first time, that some malocclusions in adults can cause tooth loss and others are protective. This should be weighed in the decision making process for orthodontic treatment.

Longitudinal association between posterior occlusal contact and dementia development in a large retrospective cohort study using a Japanese claims database

This study examines the association between posterior occlusal contact and the risk of dementia development in the Japanese population, utilizing Eichner classification to evaluate occlusal status. Data from Japanese health insurance claims were analyzed for the period from April 2016 to March 2022. Participants had undergone specific health checkups, had no prior history of dementia, and were classified according to their dental occlusal contact. Dementia diagnoses were determined using ICD-10 codes, and participants were divided into three groups-A, B, and C-based on the Eichner classification, which indicates the extent of occlusal contact. Over an average follow-up period of 35.6 months, 691 dementia were identified among 931,309 participants. Those diagnosed with dementia were more likely to belong to Eichner B and C groups, signifying reduced occlusal contact. After adjusting for covariates, the hazard ratios (95% confidence intervals) for Eichner B and C were 1.73 (1.31-2.28) and 2.10 (1.35-3.26), respectively. Sensitivity analyses confirmed these findings in adults aged 60-75. These findings suggest that reduced posterior occlusal contact correlates with an increased risk of dementia. Since the study is limited to participants under the age of 75, further research is required to determine its generalizability to older populations.

Association Between Reduced Posterior Occlusal Contact and Alzheimer's Disease Onset in Older Japanese Adults: Results from the LIFE Study

BACKGROUND

An association between poor oral health and cognitive decline has been reported. Most of these studies have considered the number of teeth as a criterion, only a few studies have analyzed the relationship between occlusal status and Alzheimer's disease (AD).

OBJECTIVE

To elucidate whether posterior occlusal contact is associated with AD, focusing on the Eichner classification, among an older population aged 65 years or older in Japan.

METHODS

This study used monthly claims data of National Health Insurance in Japan from April 2017 to March 2020. The outcome was newly diagnosed AD defined according to ICD-10 code G30. The number of teeth was estimated by dental code data, and occlusal contact was divided into three categories, namely A, B, and C, according to the Eichner classification. Multivariate Cox proportional hazards models were used to analyze the association between a new diagnosis of AD and the Eichner classification.

RESULTS

A total of 22,687 participants were included, 560 of whom had newly diagnosed AD during a mean follow-up period of 12.2 months. The AD participants had a lower proportion of Eichner A and a higher proportion of Eichner C. After adjusting for covariates, hazard ratios (95% confidence intervals) with Eichner B and C were 1.34 (1.01-1.77) and 1.54 (1.03-2.30), respectively.

CONCLUSION

In older people aged≥65 years old, reduced posterior occlusal contact as well as tooth loss have an impact on AD. This study emphasizes the importance of paying attention to occlusal contacts to reduce the risk of AD.

Tooth Loss and Associated Factors in Mexican Older Adults in Nursing Homes: A Multicenter Cross-Sectional Study

The objective of this study was to determine the experience of tooth loss and associated factors in older adults and elderly residing in nursing homes. A cross-sectional study was conducted in Mexican older adults and elderly aged ≥60 years living in four nursing homes (two in Mexico City, Mexico: one in Cuernavaca, Morelos, and one in Oaxaca, Oaxaca). The data were collected at the facility (home nursing) by two dentists in 2019. To determine the number of tooth loss and DMFT, a clinical oral examination was performed. In addition, a questionnaire was applied to determine diverse independent variables (demographic, socioeconomic, and behavioral). The analysis was performed using nonparametric tests and negative binomial regression (p < 0.05). 257 subjects were included. The mean age was 81.25 ± 9.02 years, and 60.7% were women. The mean number of lost teeth was 18.78 ± 9.05 (women = 19.43 ± 8.59 and men = 17.77 ± 9.68; p > 0.05). In the multivariate negative binomial regression model, it was found that, for each one-year increase in age, the mean tooth loss increased 0.92% (p < 0.05). In current smokers (p < 0.01) and in those who brush their teeth < 2 times a day (p < 0.01), the average of tooth loss increased 22.04% and 61.46%, respectively. The experience of tooth loss in Mexican older adults and elderly was high. Demographic (age) and habit of behavior (tobacco use and less frequent tooth brushing) were associated with increased tooth loss. It is important to promote oral health programs for institutionalized older adults.

How the Loss of Second Molars Corresponds with the Presence of Adjacent Third Molars in Chinese Adults: A Retrospective Study

Third molars (M3s) can increase the pathological risks of neighboring second molars (M2s). However, whether the M3 presence affects M2 loss remains unknown. This retrospective study aimed to reveal the reasons for M2 loss and how M2 loss relates to neighboring M3s. The medical records and radiographic images of patients with removed M2(s) were reviewed to analyze why the teeth were extracted and if those reasons were related to adjacent M3s. Ultimately, 800 patients with 908 removed M2s were included. In the included quadrants, 526 quadrants with M3s were termed the M3 (+) group, and the other 382 quadrants without M3s were termed the M3 (−) group. The average age of patients in the M3 (+) group was 52.4 ± 14.8 years and that of the M3 (−) group was 56.7 ± 14.9 years, and the difference between the two groups was statistically significant (p < 0.001). Of the 908 M2s, 433 (47.7%) were removed due to caries and sequelae and 300 (33.0%) were removed due to periodontal diseases. Meanwhile, 14.4% of the M2s with adjacent M3s were removed due to distal caries and periodontitis, which were closely related to the neighboring M3s; this percentage was much lower when M3 were absent (1.8%). Additionally, 42.2% of M3s were removed simultaneously with neighboring M2s. The presence of M3s, regardless of impaction status, was associated with an earlier loss of their neighboring M2s.

Real-world evidence of the impact of obesity on residual teeth in the Japanese population: A cross-sectional study

BACKGROUND

Tooth loss is associated with nutritional status and significantly affects quality of life, particularly in older individuals. To date, several studies reveal that a high BMI is associated with tooth loss. However, there is a lack of large-scale studies that examined the impact of obesity on residual teeth with respect to age and tooth positions.

OBJECTIVE

We assessed the impact of obesity on the number and position of residual teeth by age groups using large scale of Japanese database.

METHODS

This was a cross-sectional study of 706150 subjects that were included in the database that combined the data from health insurance claims and health check-up, those lacking information about BMI, HbA1c level, smoking status, and the number of residual teeth were excluded. Thus, a total of 233517 aged 20-74 years were included. Subjects were classified into 4 categories based on BMI, and the number of teeth was compared between age-groups. The percentage of subjects with residual teeth in each position was compared between groups with obesity (BMI ≥25.0 kg/m2) and non-obesity. Logistic regression analysis was performed to clarify whether obesity predicts having <24 teeth.

RESULTS

Higher BMI was associated with fewer teeth over 40s (P for trend <0.0001 when <70s). Obesity was associated with the reduction of residual teeth in the maxillary; specifically, the molars were affected over the age 30. Smoking status further affected tooth loss at positions that were not affected by obesity alone. After adjusting for age, sex, smoking status, and HbA1c ≥6.5%, obesity remained an independent predictive factor for having <24 teeth (ORs: 1.35, 95% CIs: 1.30-1.40).

CONCLUSIONS

We found that an increase in BMI was associated with a decrease in the number of residual teeth from younger ages independently of smoking status and diabetes in the large scale of Japanese database.

Impact of oral health literacy and psychoactive substances on tooth loss in adolescents

The aim of the present study was to investigate associations between tooth loss, and oral health literacy, the use of multiple psychoactive substances, and the reason for the last dental appointment in adolescents. A cross-sectional study was conducted with a representative sample of 746 adolescents aged 15 to 19 years in Campina Grande, Brazil. Parents/guardians answered a sociodemographic questionnaire. The adolescents answered the Brazilian version of the Rapid Estimate of Adult Literacy in Dentistry (BREALD-30), the Alcohol, Smoking and Substance Involvement Screening Test, and an oral health questionnaire from the National Oral Health Survey. The adolescents were then examined by two examiners who had undergone training and calibration exercises for the diagnosis of tooth loss due to caries (K> 0.80). Associations between variables were investigated using robust logistic regression analysis for complex samples (α = 5%). The prevalence of tooth loss was 17.4%. Oral health literacy (OR = 0.93; 95% CI: 0.89-0.97) was inversely associated with tooth loss, while multiple psychoactive substance use (OR = 2.01; 95% CI: 1.09-3.69) and last dental visit for treatment/symptoms (OR = 3.05; 95% CI: 1.73-5.36) were directly associated with tooth loss. Oral health literacy, multiple psychoactive substance use, and reason for last dental appointment exerted an influence on tooth loss among adolescents.

Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults

STUDY OBJECTIVES

First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals.

METHODS

NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway.

RESULTS

Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038).

CONCLUSIONS

The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://clinicaltrials.gov/ct2/show/NCT01868295; Identifier: NCT01868295.

CITATION

Chen H, Elham E, Li Y, et al. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.

Periodontal health predicts self-rated general health: A time-lagged cohort study

OBJECTIVES

There is limited evidence of a temporal relationship between periodontal diseases and self-perceived general health. To plug this knowledge gap, we aimed to assess how periodontal health affects future self-rated health (SRH).

METHODS

We collected data from five waves of an annual nationwide Japanese survey of dental patients from 2015 to 2019. The analysis of repeated measurements included 9306 observations from 4242 patients aged 20 years or older. The clinical periodontitis measurements were bleeding on probing, deepest periodontal pocket depth and most severe clinical attachment loss (CAL). We used a self-administered questionnaire to collect data on sociodemographic characteristics, diabetes history, health behaviour, SRH and self-reported periodontitis. We applied 2-level ordered logistic regression models for repeated measurements to examine the relationships between SRH (time t) and 1-year-lagged periodontal health (time t-1) after adjusting for covariates.

RESULTS

The percentage of SRH responses recorded at time t as 'good', 'moderate' and 'poor' were 36.9%, 52.4% and 10.7%, respectively. Multivariate analyses showed that the risk of poorer SRH at time t increased in patients with CAL ≥7 mm (odds ratio [OR] = 1.15, 95% confidence interval [CI] = 1.02-1.30), those who reported bleeding gums (OR = 1.33, 95% CI = 1.21-1.46) and those who perceived swollen gums (OR = 1.40, 95% CI = 1.26-1.56) at time t-1. Sensitivity analyses using the 4-year follow-up model and 3-year-lagged cohort model also showed consistent results.

CONCLUSION

Periodontitis shows a gradual contribution to future SRH in dental patients, even after adjusting for sociodemographic characteristics, general health and health-related behaviours.

Risk Factors for Tooth Loss in Patients with ≥25 Remaining Teeth Undergoing Mid-Long-Term Maintenance: A Retrospective Study

Tooth loss represents a diffused pathologic condition affecting the worldwide population. Risk factors have been identified in both general features (smoking, diabetes, economic status) and local tooth-related factors (caries, periodontitis). In this retrospective study, we examined the data of 366 patients with a large number of remaining teeth (≥25) undergoing maintenance therapy in order to identify specific risk factors for tooth loss. The number of remaining teeth, number of non-vital teeth, and number of occlusal units were investigated for their correlation with tooth loss. The mean follow-up of patients was 9.2 years (range 5 to 14). Statistically significant risk factors for tooth loss were identified as number of remaining teeth at baseline (p = 0.05), number of occlusal units (p = 0.03), and number of non-vital teeth in posterior regions (p < 0.001). Multiple logistic regression showed that the number of occlusal units and number of non-vital teeth in the posterior regions were significantly associated with a greater risk of tooth loss (odds ratio 1.88 and 3.17, respectively). These results confirm that not only the number of remaining teeth, but also their vital or non-vital status and the distribution between the anterior and posterior regions influence the long-term survival.

Multilevel Analysis of the Association of Dental-Hygienist-Related Factors on Regular Dental Check-Up Behavior

Few studies have examined the factors related to dental clinics during dental check-ups. We examined the association between dental-hygienist-related factors and patients’ regular dental check-ups. This nationwide cross-sectional study was based on a survey conducted in Japan in 2014. The analyzed population included 12,139 patients from 1181 dental clinics. We used three-level Poisson regression analysis, considering patient‒clinic‒prefecture, to examine the association of dental-hygienist-related factors with dental check-up behavior. Patients attending treatment and regular check-ups constituted 63.0% and 37.0%, respectively. The adjusted prevalence ratios (PRs) for patients undergoing regular dental check-ups at dental clinics with dedicated dental hygienists’ units, spending ≥20 min in patient education (compared to 0 min), and with three or more dental hygienists (compared to 0 hygienists) available were 1.17 (95% confidence interval [CI]: 1.06–1.30), 1.25 (95%CI: 1.07–1.46), and 2.05 (95%CI: 1.64–2.56), respectively. The median PR indicates that when a patient randomly moves to another dental clinic with more regular dental check-ups, this prevalence increased 1.69 times. These results suggest that dental check-up behavior is determined not only by individual factors but also dental-clinic-level factors. Improving the dental-hygienist-related factors is necessary to encourage people to visit dentists for regular check-ups.

Association between high psychological distress and poor oral health-related quality of life (OHQoL) in Japanese community-dwelling people: the Nagasaki Islands Study

Background

We investigated the association between psychological distress and oral health status/oral health-related quality of life (OHQoL) in Japanese community-dwelling people.

Methods

We conducted a cross-sectional study using data from the Nagasaki Islands Study. A total of 1183 (455 men and 728 women) has been analyzed in this study. Psychological distress was measured using the Kessler Psychological Distress Scale (K6). Oral health status was measured by dental examination. The OHQoL was measured using the General Oral Health Assessment Index (GOHAI). We defined the total score of ≥5 points on the K6 as high psychological distress (high-K6 group).

Results

The multiple linear regression analysis to identify the GOHAI showed that gender, K6, the total number of teeth, the number of dental caries, and visiting a dental clinic within the past 6 months significantly associated with the GOHAI. Among all of these variables, high-K6 (≥ 5) was a substantial contributing factor of the GOHAI (β = − 0.23, 95% Cl − 2.31 to −1.41, p < 0.0001).

Conclusions

It is likely that the individual with high psychological distress was strongly related to poor OHQoL even in the general population.

A multilevel analysis of the importance of oral health instructions for preventing tooth loss: The 8020 Promotion Foundation Study of Japanese Dental Patients

Background

Many studies have reported risk factors for tooth loss. Oral health instruction is considered effective at improving oral health behavior and oral health. However, few studies have examined the relationship of dental clinic factors, such as the number of dental hygienists and implementation of oral health instructions, with tooth loss. Here, we conducted a multilevel analysis to clarify the dental clinic risk factors associated with tooth loss.

Methods

Baseline surveys were conducted at 1216 dental clinics in 46 prefectures in Japan, and 12,399 dental patients aged 20 years and over underwent oral examinations and completed a questionnaire. The dental clinics also completed a questionnaire at baseline. A 3-year follow-up survey included 2488 patients in 585 dental clinics. Multilevel multivariate logistic regression analysis was used to examine the risk of tooth loss at the patient and clinic levels.

Results

Of the patient variables, older age, higher mean probing pocket depth, current or past smoking, and bleeding during tooth brushing were associated with higher risks of tooth loss. Individuals with many teeth who visited dental clinics for maintenance were at significantly lower risk of tooth loss. Of the clinic variables, patients attending dental clinics with four or more dental hygienists had a significantly lower risk of tooth loss (OR 0.68, 95% CI 0.50–0.99). Patients attending dental clinics that provide oral health instructions for 20 min or more had a significantly lower risk of tooth loss (OR 0.69, 95% CI 0.50–0.96).

Conclusions

In addition to individual risk factors for tooth loss, dental clinic factors such as length of oral health instruction and number of dental hygienists are associated with tooth loss. In dental clinics, ensuring sufficient time for dental hygienists to provide oral health instructions can help prevent tooth loss in dental patients.

Risk Factors for Tooth Loss in Patients Undergoing Mid-Long-Term Maintenance: A Retrospective Study

In this retrospective study, we identified risk factors for tooth loss in patients undergoing mid-long-term maintenance therapy. We surveyed 674 maintenance patients for ≥5 years after active treatment who visited a dental clinic between January 2015 and December 2016. Of these, 265 were men (mean age 54.6 ± 8.0 years old) and 409 were women (mean age 54.0 ± 7.9 years old). Study variables included patient compliance, sex, number of teeth lost, cause of tooth loss (dental caries, periodontal disease, root fracture, others, vital or non-vital teeth), age at start of maintenance, number of remaining teeth at start of maintenance, smoking, use of salivary secretion inhibitors, presence of diabetes mellitus, condition of periodontal bone loss, and use of a removable denture. Most lost teeth were non-vital teeth (91.7% of all cases) and the most common cause of tooth loss was tooth fracture (62.1% of all cases). A statistically significant risk factors for tooth loss was number of remaining teeth at the start of maintenance (p = 0.003).

Association between dental consultation and oral health status among male Japanese employees

Objective

To investigate the association between dental consultation and oral health status among male Japanese employees.

Methods

The participants were 3351 male employees who received a workplace oral health examination conducted at the ages of 35, 40, 45, 50, 55, and 59 years before retirement in conjunction with an annual health checkup. Data on dental expenditures were collected from health insurance claims. The number of dental visits and dental care expenses, alone or in combination, were used as indices of the dental consultation status for the analyses. The effects of dental consultation status on oral health status (number of total teeth, number of decayed teeth, and periodontal status) were analyzed using multivariate multinomial logistic regression analyses adjusted for confounders.

Results

Multivariate analyses revealed that the odds ratio (OR) for 20‐27 teeth (losing 1‐8 teeth) was significantly higher (OR 1.4, 95% confidence interval (CI) 1.1‐1.7) in those who had a high number of dental visits and high dental care expenses than in those who did not have a dental visit. By contrast, the ORs for ≤19 teeth (losing ≥9 teeth), having ≥3 decayed teeth, or having a periodontal pocket ≥6 mm were significantly lower (OR 0.2, 95% CI 0.1‐0.6; OR 0.5, 95% CI 0.3‐0.6; OR 0.7, 95% CI 0.5‐1.0, respectively) in those who had fewer dental visits and lower dental care expenses.

Conclusions

These results imply that the dental consultation status is associated with oral health status among male employees.