Factors Affecting Future Caries Occurrence Among Preschoolers in Northern Guangdong: A Longitudinal Study

PURPOSE: This study aimed to investigate the new development of caries among preschoolers in northern Guangdong and to assess caries-related factors to distinguish groups with different caries risk levels. METHODS: Baseline data were recorded for participants from September to November 2019, and participants were reexamined from September to November 2020. A longitudinal observation of 11,973 preschoolers was conducted. The simplified debris index (DI-S) and decayed-missing-filled tooth (dmft) index values were obtained for each participant. RESULTS: Factors associated with whether caries would occur in the future and one-year increase in dmft (Δdmft) included baseline dmft, baseline DI-S, and baseline age. The risk ratio (RR) of caries occurrence and the number of teeth with new-onset caries were 4.482 (95% confidence interval, 4.056–4.957) and 2.945 (2.742–3.165) in the participants with baseline dmft ≥3, which were higher than those with baseline dmft =1 or 2. In the baseline caries-free group, whether caries would occur in the future was related to the baseline DI-S (95% confidence interval, 0.022–0.062). The caries incidence of maxillary central incisors (27.9%) was the highest among teeth of preschoolers without caries at baseline, whereas the caries incidence of mandibular first deciduous molars (42.7%) was the highest among teeth of preschoolers with caries at baseline. CONCLUSION: Baseline dmft is a good predictor of future caries. Children with baseline caries-free status, baseline dmft >0, and baseline dmft ≥3 should be treated with preventive interventions of different intensities and frequencies. The occurrence of future caries in baseline caries-free participants is related to oral hygiene status. Measures to prevent caries on smooth surfaces, such as topical fluoridation, should be applied to all preschoolers. Preschoolers with caries at baseline may be given priority for pit and fissure sealing.