Early Adolescent Caries Incidence and Risk Factors

Objective: Identification of gender-specific risk factors for age 9-13 caries incidence.

Methods: Iowa Fluoride Study participants were evaluated for presence of caries by trained and calibrated dentists at 9 and 13 years. Net caries increment was defined as age 13 minus age 9 D₂₊FS on permanent incisors and 1st molars. Questionnaires mailed at 6-month intervals to participants/parents recorded the children's water sources; daily toothbrushing frequency and duration; and brand-specific weekly beverage intakes. Documented water fluoride levels from municipal sources and assay of private sources were used to obtain subject-specific water fluoride levels (ppm). Area-under-the-curve trapezoidal method was used to estimate age 9.5-13 daily beverage intakes and frequencies. Logistic regression models for any D₂₊F caries increase adjusted for time between exams, sex and presence of sealants. Regressions separately assessed gender-specific associations with water fluoride level, fluoride intake, beverage intakes, and toothbrushing frequency and duration.

Results: Subjects with both dental exams and sufficient questionnaire returns (n=201) were included in the analyses. Sixteen percent had an increase in D₂₊FS, with 12% having increased D₂₊FS on pit and fissure surfaces and 6% with increased D₂₊FS on smooth surfaces. After adjusting for time between exams, sex and presence of sealants, D₂₊F incidence in males was positively associated with oz. of sport drink consumption (OR=1.21, p=0.04) and high-sugar beverages (OR=1.10, p=0.02), but negatively associated with toothbrushing frequency (OR=0.25, p=0.03) and minutes (OR=0.28, p=0.04). D₂₊F incidence in females was positively associated with oz. of high-sugar beverages (OR=1.10, p=0.05) and negatively associated with water fluoride level (OR=0.75, p=0.02). Results for pit and fissure incidence were similar. Smooth surface D₂₊F incidence showed no significant associations.

Conclusion: While positive effects of toothbrushing and negative effects of high-sugar beverages are well documented, gender differences are evident in the relative strengths of those associations.

Supported by NIH grants R01-DE09551, R01-DE12101, and M01-RR00059.