Enamel Caries in Young Adults and Progression From Adolescence: Fit Futures, a Longitudinal Cohort Study

INTRODUCTION AND AIMS: This study aimed to determine the extent and trajectory of enamel caries from adolescence through young adulthood and the associated factors. METHODS: Data were from the first and third Fit Futures (FF) studies that followed a cohort of Norwegians from the first year of upper secondary school (FF1 2010-2011, age 17) for 10 years (FF3 2021-2022, age 27). Participants answered questionnaires and underwent clinical dental examinations. The study sample included participants with data on caries and restorations at both ages 17 and 27 (N = 584, 53% of the original FF1 cohort, 53% women). Data were analysed using descriptive statistics, and associations between risk factors and caries activity were examined using regression models. RESULTS: Almost all participants had enamel caries lesions (median 12.0 and 9.0 lesions at ages 17 and 27, respectively), and 64% had lesions that had progressed into dentin during the observation period. At the tooth surface level, 10% of all surfaces had enamel caries at age 17, of which 18% had progressed to dentin caries by age 27. The highest progression rates were observed on proximal surfaces and for premolars of the upper jaw. In regression analyses, high caries activity was associated with female sex, low socioeconomic status, poorer self-reported general health, poor oral hygiene habits, and high soft drink intake. CONCLUSION AND CLINICAL RELEVANCE: Enamel caries lesions were almost ubiquitous, but more than 80% did not progress over a 10-year period, lending strong support to nonoperative treatment of such lesions. Nevertheless, the study demonstrated relatively high caries activity during the transition from adolescence to adulthood and underlines the importance of dietary guidance and oral hygiene motivation to prevent caries. Having medium or low socioeconomic status and facing general health issues should also be considered important caries risk factors.