Perioperative oral management is a novel approach in dentistry to prevent the adverse events associated with medical treatments such as cancer surgery, radiotherapy, and chemotherapy. Perioperative oral management involves not only oral care but also the treatment and eradication of oral infections; this requires an understanding of both general diseases and dental practices such as oral surgery and prosthetic dentistry. Dentists specializing in preventive dentistry should actively participate in perioperative oral management, as this practice will further the development of procedures for preventive dentistry. However, standard oral management methods based on evidence of their effectiveness have not been established. Perioperative oral management was initiated in 2012 at Nagasaki University Hospital. Here, we outline our approach to perioperative oral management and some of the multicenter clinical studies at Nagasaki University Hospital.

Access to healthcare is one determinant of health inequalities. The number of teeth present is associated with access to dental healthcare. No study has examined the inequalities in dental care access among a wide range of age groups in Japan, while taking into consideration the number of teeth present. This cross-sectional study examined who received regular dental checkups by analyzing data from a survey conducted by the 8020 Promotion Foundation in 2015. The survey consisted of questionnaires mailed to 5,000 people, aged 20 to 79, who were selected by stratified two-stage random sampling from Japanese municipalities, and 2,465 people responded (response rate=49.3%). Data without missing responses from 2,161 participants were analyzed. Poisson regression was used to estimate the prevalence ratio (PR) for determining the association of sex, age, subjective economic status, and number of present teeth during a regular dental checkup. The mean age of the participants was 52.4±15.5 years. There were 1,008 men and 1,153 women; 34.9% of all participants had received regular dental checkups. Percentages of receiving regular dental checkups among people with a higher, middle, and lower economic status were 39.7, 36.4, and 28.5%, respectively. The multivariate-adjusted Poisson regression showed that women and the older participants (aged 60–79 years) more likely to receive regular dental checkups. Participants with a lower economic status and fewer teeth were less likely to receive regular dental checkups. The PR of people with a lower economic statuses compared with those with a higher economic status was 0.74 (95% confidence interval=0.62; 0.88). There were social inequalities of access to regular dental checkups. Policies should aim to improve the access to regular dental checkups, regardless of the social environment.

In recent years, many studies have reported the relationship between oral health and dementia. Even though the objective evaluation of chewing (gummy 15-sec mastication test) is low, the elderly, who think that they are able to chew all kinds of food, have lower cognitive function than the elderly who do not think so. In order to confirm this hypothesis, we devised a Composite Index of Mastication (CM) consisting of subjective evaluation (able to chew / not able to chew) and objective evaluation (gummy chewing for 15 sec into more than 12 pieces / not able to chew; less than 12 pieces). In addition, since the number of current teeth has a positive correlation with the gummy 15-sec value, current teeth (able to chew; more than 20 teeth / not able to chew; less than 20 teeth) was used as a proxy variable for objective evaluation, and was used for analysis. Data was collected from a cross-sectional study conducted in 2012. After excluding participants with missing data, we analyzed data from 371 participants (142 males, mean age 71.2±2.9 years). Cognitive function was measured using the cognitive function reduction screening tool CADi (Cognitive Assessment for Dementia, iPad version) that was developed by Shimane University. Twenty-four (6.5%) participants were suspected to have cognitive decline. As a result of logistic regression analysis with the presence or absence of suspicion of cognitive decline as the objective variable, the odds ratio (OR) for CM (subjective; able to chew & objective; not able to chew) was 6.65 times higher compared with CM (subjective; able to chew & objective; able to chew). In addition, OR for CM (subjective; able to chew & teeth number; less than 20 teeth) was 10.29 times higher compared with CM (subjective; able to chew & teeth number; 20 teeth or more). The value of OR was similar after adjustment for basic attributes and items related to cognitive decline. The findings support the validity of the hypothesis.

The purpose of this study was to estimate the tooth retention status in Suginami City, a part of the Tokyo metropolitan area, involving residents aged 80 years old. The Suginami City government surveyed the number of retained teeth by sending out a questionnaire to all residents aged 80 years old in 2012. In total, 2,265 valid responses were returned, representing 60.4% of all 80-year-old residents. The number of retained teeth was 16.43±10.53 (mean±SD), and 47.4% of the respondents still had more than 20 teeth. No sex-based difference was observed. The distribution of the long-term care need (support or nursing care need present of absent) and long-term care insurance charge (4 categories according to income) was obtained for 1,846 persons who agreed to disclose their personal information. Distributions in the other 1,880 people, including those who did not respond and those who did not agree to disclose information, were obtained by excluding the above group from all other residents of that age (3,726 persons; 23 people had died since the time of the questionnaire survey). As a result, those who disclosed tended to be healthier and had a higher income. The number of retained teeth and the number of persons with more than 20 teeth among all residents of that age according to the care need and income were estimated from the above-mentioned distribution results and the distribution of the number of all residents at the age of 80. The mean number of retained teeth and rate of persons with more than 20 teeth among all residents were estimated at 16.5 teeth /47.7% by the distribution of care need, and 16.5 teeth /47.7% by the distribution of income. These estimated values were almost the same as the results for the questionnaire respondents. Furthermore, 274 respondents under want an optional oral examination. The mean number of retained teeth based on the results of oral examination was 0.5 teeth lower than that of the questionnaire survey, but the rate of persons with more than 20 teeth based on the results of the oral examination was 0.4 points higher than that of the questionnaire survey. The results of the present study support the fact that almost half of Suginami City residents at the age of 80 had achieved 8020 in 2012.

The purpose of this study was to examine the association between current methods for carrying out dental health examinations for 18-month-old children and type O₂ evaluation results in designated cities and special wards with public health centers.

The target of this study was 94 designated cities and special wards with public health centers in Japan. Methods for carrying out dental health examinations for 18-month-old children were investigated using postal questionnaires from November 20 to December 28 2015, and responses were received from 68 cities and wards (response rate: 72.3%). The proportion of children with a caries attack pattern of type O₂ was estimated using documents published by the Ministry of Health, Labour and Welfare.

As a result, the main method for carrying out health examinations was through public health centers, which occurred in 66 cities and wards (97.1%). Of those, 43 cities and wards (63.2%) carried them out together with medical health examinations, and 21 cities and wards (30.9%) carried them out alone.

In 23 cities and wards (33.8%), children with one or more high-risk factors, according to the results of a medical interview, were determined to be type O₂, whereas 19 cities and wards (27.9%) confirmed type O₂ based on plaque coverage and responses to a medical interview. The proportion of type O₂ children differed markedly among cities and wards, ranging from 1.1 to 95.8%.

Correlation analysis was performed on the proportion of type O₂ children, history of caries, and dental health examination consultation rate. No correlation was observed between the proportion of type O₂ children and history of caries.

Analysis of whether the proportion of type O₂ children was associated with the method for carrying out health examinations or method for determining type O₂ revealed a correlation with the method for carrying out health examinations (p<0.01) and method for the evaluating type O₂ (p<0.05).

Prenatal dental health examinations were carried out in 56 cities and wards (82.4%), and 51 cities and wards (75.0%) carried out dental health examinations for children at ages other than 18 months and three years.

These results revealed marked differences in the method for determining type O₂ by city and ward, and suggest that the differences are associated with the method for carrying out health examinations and criteria for determining type O₂.