Masayasu Kitamura

Early Childhood Caries

Dental caries is one of the most common childhood diseases, and people continue to be susceptible to it throughout their lives. Although dental caries can be arrested and potentially even reversed in its early stages, it is often not self-limiting and progresses without proper care until the tooth is destroyed. Early childhood caries (ECC) is often complicated by inappropriate feeding practices and heavy infection with mutans streptococci. Such children should be targeted with a professional preventive program that includes oral hygiene instructions for mothers or caregivers, along with fluoride and diet counseling. However, these strategies alone are not sufficient to prevent dental caries in high-risk children; prevention of ECC also requires addressing the socioeconomic factors that face many families in which ECC is endemic. The aim of this paper is to systematically review information about ECC and to describe why many children are suffering from dental caries.

Quantification of Modified Tyrosines in Healthy and Diabetic Human Urine using Liquid Chromatography/Tandem Mass Spectrometry.

The quantification of urinary oxidized tyrosines, dityrosine (DiY), nitrotyrosine (NY), bromotyrosine (BrY), and dibromotyrosine (DiBrY), was accomplished by quadruple liquid chromatography-tandem mass spectrometry (LC/MS/MS). The sample was partially purified by solid phase extraction, and was then applied to the LC/MS/MS using multiple-reaction monitoring (MRM) methods. The analysis for the DiY quantification was done first. The residual samples were further butylated with n-butanol/HCl, and the other modified tyrosines were then quantified with isotopic dilution methods. MRM peaks of the modified tyrosines (DiY, NY, BrY, and DiBrY) from human urine were measured and the elution times coincided with the authentic and isotopic standards. The amounts of modified tyrosines in healthy human urine (n = 23) were 8.8 ± 0.6 (DiY), 1.4 ± 0.4 (NY), 3.8 ± 0.3 (BrY), and 0.7 ± 0.1 (DiBrY) µmol/mol of creatinine, respectively. A comparison of the modified tyrosines with urinary 8-oxo-deoxyguanosine, pentosidine, and Nε-(hexanoyl)lysine was also performed. Almost all products, except for NY, showed good correlations with each other. The amounts of the modified tyrosines (NY, BrY, and DiBrY) in the diabetic urine were higher than those in the urine from healthy people.

Relationship Between Periodontal Status and HbA1c in Nondiabetics

OBJECTIVES Many studies have reported an association between diabetes and periodontitis. We analyzed the periodontal status and glycosylated hemoglobin (HbA1c) level in nondiabetic subjects to investigate the relationship between periodontitis and glucose control in nondiabetics. METHODS Periodontal status, HbA1c, serum cholesterol, triglyceride, body mass index (BMI), and demographic variables were assessed in 141 Japanese adults. The difference in the HbA1c level was evaluated among subjects according to periodontal status. RESULTS After adjusting for age, gender, BMI, and smoking, alcohol, and exercise habits as covariates, the mean HbA1c was significantly elevated with periodontal deterioration (P = 0.023). CONCLUSIONS There was a significant relationship between periodontal status and HbA1c levels in nondiabetics.

Association of periodontitis with carotid artery intima–media thickness and arterial stiffness in community-dwelling people in Japan: The Nagasaki Islands study

OBJECTIVE Recent studies have suggested an association between periodontitis and atherosclerosis; however, the relationship between periodontal status and arterial alterations should be clarified. The purpose of this study was to examine associations between periodontal status and carotid intima-media thickness (cIMT) and arterial stiffness using the cardio-ankle vascular index (CAVI) in community dwellers. METHODS A community-based cross-sectional study of 1053 subjects ≥40 years with 10 teeth or more was conducted in Goto, Japan from 2008 to 2010. RESULTS In a multiple linear regression analysis adjusted for age, sex, number of present teeth, and other confounders, each 1-mm increase in mean periodontal pocket depth corresponded to a 0.02-mm increase in maximal cIMT (β = 0.018; P = 0.049) and also to a 0.1 increase in mean CAVI (β = 0.133; P = 0.040). In addition, each 1-mm increase in the mean periodontal attachment loss corresponded to a 0.01-mm increase in maximal cIMT (β = 0.013; P = 0.040). A multiple logistic regression analysis revealed that each 1-mm increase in mean periodontal pocket depth was associated with an increased risk of a maximal cIMT >1 mm (adjusted odds ratio [OR], 1.430; 95% confidence interval [CI], 1.067-1.918; P = 0.017) and mean CAVI of ≥8 (OR, 1.323; 95% CI, 1.003-1.743; P = 0.047). Furthermore, each 1-mm increase in mean periodontal attachment loss was associated with an increased risk of a maximal cIMT >1 mm (OR, 1.251; 95% CI, 1.032-1.516; P = 0.022). CONCLUSION A linear, dose-dependent relationship was found between periodontal pocket depth, cIMT, and arterial stiffness.

Monitoring time-related trends in dental caries in permanent teeth in Japanese national surveys

OBJECTIVES According to dental examinations of 3- and 12-year-old children conducted throughout Japan, the prevalence of dental caries in children is decreasing. However, little is known about changes in the prevalence of dental caries in adults. This study analysed past and present prevalences of dental caries in permanent teeth and predicted future trends in dental caries in adults. METHODS Data were sourced from nine national dental surveys conducted in Japan at 6-year intervals from 1957 to 2005. Data from oral examinations were recorded as indices of decayed, missing and filled teeth. RESULTS The mean number of filled teeth increased markedly, whereas mean numbers of decayed teeth and missing teeth decreased substantially in people aged ≥ 40 years. By contrast, the mean number of filled teeth first increased and then decreased in groups aged 5-39 years. CONCLUSIONS Among Japanese respondents sampled in a series of cross-sectional studies between 1957 and 2005, the incidence of dental caries in young adults decreased, suggesting a decrease in prevalences of dental caries in future generations. However, this tendency was not observed in respondents aged ≥ 40 years. The results suggest adults will experience less dental caries in the near future.

Relationship among salivary antioxidant activity, cytokines, and periodontitis: The Nagasaki Island study

AIM Antioxidant activities and cytokine levels in human body fluids are considered to be strongly associated with periodontitis. The aim of this study was to elucidate the relationship between salivary antioxidant activities against superoxide or hydroxyl radical, cytokines, and periodontal conditions through a community-based cross-sectional study conducted in Goto city, Japan. MATERIALS AND METHODS Saliva samples were analysed for superoxide or hydroxyl radical scavenging activities and cytokine levels from 160 participants. We demonstrated that saliva contained superoxide and hydroxyl radical scavenging activities by using electron spin resonance with a spin-trapping agent. The concentrations of eight cytokines were measured using multiplex bead assays. RESULTS There were significant differences in salivary superoxide or hydroxyl radical scavenging activity, and the levels of Interleukin-1β, Interleukin-6, and Interleukin-8 between periodontitis classifications. Multivariate stepwise logistic regression model showed that salivary superoxide and hydroxyl radical scavenging activities were significantly associated with the classification of periodontitis. In addition, salivary superoxide scavenging activity was found to have significant association with all periodontal parameters using multiple linear regression analysis. CONCLUSIONS These findings suggest that the evaluation of salivary antioxidant activities, as assessed by electron spin resonance, are associated with periodontitis and various clinical variables in community-dwelling participants (ClinicalTrials.gov number NCT01742728).

Relationship between Metabolic Syndrome and Number of Teeth in Japan

The 2004 Japanese National Health and Nutrition Survey collected data on several measures, including self-reported dental health. In addition, this was the first nationwide survey to focus on metabolic syndrome (MetS) in Japan. Therefore, the authors used this nationwide data set to assess the relationship between number of teeth present and MetS. Anonymized data were available with permission from the Ministry of Health, Labour and Welfare of Japan. Data from 3,195 men and women aged 35 to 99 y were examined, and logistic regression analyses were used to evaluate the association between number of teeth and MetS. Moreover, the authors performed an analysis of covariance to compare the mean number of teeth between those with and those without MetS, after adjusting for confounders. In comparison with those having ≥28 teeth, those with fewer remaining teeth demonstrated significantly higher odds of having MetS. Specifically, those having 1 to 9 teeth had higher odds of having MetS than those with more teeth and were more than twice as likely to be affected than those with ≥28 teeth. Furthermore, individuals with MetS in the age groups of 45 to 54, 55 to 64, and 65 to 74 y had significantly fewer teeth than those without MetS in the same age groups. These results suggest that the number of teeth present is associated with the prevalence of MetS in the Japanese population. Knowledge Transfer Statement: The results of this study can be used by clinicians when they examine patients with periodontal disease or extensive tooth loss to refer for a general medical examination.