The Effect of Prematurity on the Occurrence of Caries at Four Years of Age: A Prospective Cohort Study

OBJECTIVES: To evaluate the association between prematurity and dental caries occurrence at four years of age and to assess whether variables related to dental development, tooth eruption, and oral healthcare mediate this association. METHODS: A longitudinal study was conducted using data from the 2015 Pelotas (RS) Birth Cohort. The outcome was dental caries at four years, classified using ICDAS. Gestational age at birth was estimated by ultrasonography examination in 3 407 (79.7%) cases, with 3 242 (75.8%) performed during the 1st or 2nd trimester. Mediating variables included enamel defects, number of teeth at 12 months, oral hygiene practices, sugar consumption, and maternal guidance. The variables were selected using a directed acyclic graph (DAG). Associations were estimated using Poisson regression models, and mediation was assessed through structural equation modelling (SEM). Analyses were performed using STATA 18.0. RESULTS: Children born before 34 weeks had a 40% lower incidence of caries at four years compared to those born after 39 weeks, and those born between 37 and 38 weeks had a 20% lower incidence. The number of teeth mediated this relationship, indicating that lower gestational age was associated with fewer teeth at 12 months and a lower occurrence of caries. CONCLUSION: The findings highlight the importance of early dental monitoring and suggest preventive programs starting with the eruption of the first tooth, given its relevance in the occurrence of caries.