ABSTRACT
OBJECTIVES: The aim of the study was to assess patterns of longitudinal changes in caries status among school-going children in Singapore. METHODS: Dental records for a single cohort of students who received dental examinations in six standard examination years between 2009 and 2017 were analysed (n = 24 699). Group-based trajectory modelling with a zero-inflated Poisson distribution was carried out to determine dental caries trajectories in the permanent dentition. Associations between sociodemographic factors and trajectory group membership were assessed using multinomial logistic regression. RESULTS: The predicted population distribution across the four caries trajectory groups identified was 65.0% ('none'), 16.8% ('low'), 14.8% ('medium') and 3.4% ('high'). The 'none' trajectory group had a decayed, missing and filled teeth (DMFT) score of 0 throughout the 8 years. Higher baseline DMFT counts and nonlinear increases in DMFT scores were noted for the 'low', 'medium' and 'high' trajectory groups. The correlation coefficient between DMFT counts in years 6 and 8 was 0.91, as compared to 0.77 between baseline and year 1. Factors associated with the 'high' caries trajectory include lower socio-economic status, female gender, Chinese race (compared to the Indian race), enrolment in primary schools in the Eastern and Western regions of Singapore, and enrolment in public secondary schools. CONCLUSIONS: Under a nationwide school dental service, four trajectory patterns of caries counts in the permanent dentition were identified over 8 years. Among students in the 'low', 'medium' and 'high' trajectory groups, greater caries increment was noted during the transition from primary to secondary school. The correlation between DMFT counts in successive examinations was stronger in older than younger ages.
ABSTRACT
OBJECTIVE: This study, using a retrospective analysis of nationwide dental records of school-going children over 8 years, aims to identify childhood factors associated with dental caries incidence in the permanent dentition up to adolescence. METHODS: Students studying in primary and secondary schools in Singapore are eligible for free basic dental care under the nationwide School Dental Service (SDS). All available dental records, general health records, and sociodemographic data from 2009 to 2017 were extracted as anonymised records, for a full cohort of 29,617 students that were enrolled in Primary 1 in 2009. Multiple logistic regression and modified Poisson regression were applied to identify risk factors for caries incidence in the permanent dentition over 8 years. RESULTS: Caries occurred in the permanent dentition of 9389 (31.7%) students in the 8 years. Risk of caries incidence in the permanent dentition was associated with baseline caries in the primary (risk ratio [RR]: 1.88; 95% CI: 1.81, 1.95) and permanent (RR: 1.54; 95% CI: 1.47, 1.61) dentition, tooth hypoplasia (RR: 1.58; 95% CI: 1.49, 1.68), and poor baseline oral hygiene (RR: 1.07; 95% CI: 1.03, 1.12). Sociodemographic predictors of caries incidence include a lower socioeconomic status, Chinese ethnicity, female gender, and enrolment in nonmainstream schools or schools in the Eastern and Western regions of Singapore. CONCLUSIONS: Both clinical and sociodemographic factors in childhood are associated with caries incidence in the permanent dentition and can be used for structuring dental service provision and identifying caries-susceptible individuals and groups for early prevention and intervention.
