We aimed to investigate the association between long working hours and periodontitis, and whether such an association constitutes an exposure-response relationship. Data for this study were collected from the Korea National Health and Nutrition Examination Surveys conducted from 2007 to 2014; 17,533 workers (9,483 of men and 8,050 of women) were included. The odds ratios (OR) and 95% confidence intervals (CI) for the analysis of periodontitis defined as positive of Community Periodontal Index in relation to working hours were calculated using multiple logistic regression models with various stratifications. Compared to participants who worked ≤40 hours per week, the prevalence ratio (95% CI) for the periodontitis was 1.19 (1.14–1.24) and full adjusted OR (95% CI) was 1.09 (1.02–1.18) in participants who worked over 40 hours per week. The OR (95% CI) for periodontitis were 1.09 (0.99–1.19) in working group of 40< and ≥52 and 1.10 (1.01–1.20) in working group of >52 hours per week with a significant trend (p = 0.0233) even after adjusting for age, socioeconomic status, healthy behaviour, chronic disease, and dental care status. Long working hours are associated with periodontitis among Korean workers in an exposure-response manner.

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Objectives We investigated the association between parents' occupational characteristics and untreated dental caries in their children. Methods We analyzed the data of 4764 and 5862 children merged with data of their mothers and fathers, respectively, derived from the Korean National Health and Nutrition Examination Survey, 2008-2015. Dentists assessed untreated dental caries, and occupational characteristics were self-reported. The associations between untreated dental caries in children and their parents' occupational characteristics were assessed with logistic regression analysis. Results The prevalence of untreated dental caries was 18.58% and 16.39% in the mother- and father-matched data, respectively. Compared to children whose mothers worked regular hours, those whose mothers worked overtime had increased odds of untreated dental caries [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.02-1.39]. Children of female self-employed workers/employers/unpaid family workers had higher odds of untreated dental caries than those of wage earners (OR 1.18, 95% CI 1.00-1.39). The OR of untreated dental caries was higher among children with shift-working parents than those whose parents worked daytime hours (mother: OR 1.29, 95% CI 1.11-1.51; father: OR 1.36, 95% CI 1.18-1.58). Conclusions The children of non-white-collar workers, non-wage earners, and workers working overtime or doing shift work had higher odds of untreated dental caries. The effects of parental occupational characteristics on untreated dental caries differed by sex (mother versus father). Public health programs targeting the prevention of dental caries among children should consider parental occupational characteristics.

Objective: The aim of this study was to determine relationships between dental maturity and body mass index (BMI) in Korean children. Study Design: 600 Korean children aged between 5 and 10 years for whom panoramic radiographs have been obtained between 2010 and 2017 were selected. Subjects were divided into four weight-status groups: underweight, normal weight, overweight, and obese. Five lower-left permanent teeth were observed and rated. The stage of each tooth was converted into a score using the table suggested by Demirjian, and the sum of these scores was designated as the ‘maturity score’. Results: This study found statistically significant differences in dental maturity between the weight groups (analysis of variance, P=0.003), with the maturity score being higher in the obese group than in normal-weight subjects (Tukey’s post-hoc test, P=0.004). The linear regression showed a positive association between BMI and the maturity score after adjusting for sex and age (β=0.34, P<0.001). The linear regression coefficient was higher in girls (β=0.61, P<0.001) than in boys (β=0.31, P=0.02). Conclusions: These data suggest that dental maturation is positively associated with BMI in Korean children. Since many treatment decisions are made in relation to dental maturity, these findings may have implications for pediatric dental care.

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice. Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either Vitapex ® (n = 44), Metapex ® (n = 44), or Metapaste ® (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher's exact test and Kruskal-Wallis test were used to compare the tested groups. In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction. Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.