BACKGROUND

Caries increment during adolescence, including enamel caries, is rarely explored in detail. This study assessed the caries increment during the period from 12 to 18 years. The specific objectives were to examine time trends, increment variability between individuals, and whether baseline caries experience at 12 years or sex had an impact on the caries increment.

METHODS

The sample included seven birth cohorts (1996-2002; n = 23,135) from a general adolescent population in Trøndelag County, Norway. Data was based on dental records from the Public Dental Service. Two caries increment thresholds were examined at the tooth level: the enamel caries increment (ΔDT), and the caries increment at the dentin level, including missing and filled teeth (ΔDMFT). Zero-inflated Poisson models were used to account for the skewed distribution with a high proportion of zero caries increment (31.1% with ΔDT = 0 and 33.4% with ΔDMFT=0).

RESULTS

The mean caries increments for the seven cohorts were ΔDT = 3.14 (95% CI: 3.09-3.19) and ΔDMFT = 2.51 (95% CI: 2.47-2.55). A modest temporal trend of decreasing caries increment across cohorts was observed at both thresholds: ΔDT = -0.31 (95% CI: ±0.13) and ΔDMFT = -0.43 (95% CI: ±0.11). However, this decrease was small compared to the variation in caries increments between individuals. Females had slightly lower mean caries increment than males, but there was no effect of sex on the change across cohorts. Adolescents with high baseline caries experience at 12 years had higher mean caries increments compared to the intermediate or low baseline caries experience groups, and a reduction across cohorts was only seen in the two latter groups.

CONCLUSIONS

While there was a modest reduction in caries increment across cohorts, this reduction was small compared to the variation in caries increments between individuals. The change across cohorts was the same in females and males. Baseline caries experience at 12 years was a strong predictor of caries increment and the reduction across cohorts was only seen among those with lower baseline caries experience, incdicating an increased dental health disparity among Norwegian adolescents.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT05935813, Release Date: 28/06/2023.