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Estimating the prevalence of untreated caries in permanent teeth from the DMF index and lifetime caries prevalence.

AIM
To derive formulas to estimate the prevalence of untreated dental caries in permanent teeth based on the DMF index and lifetime caries prevalence.


METHODS
Data from participants, aged 5 years or older, in the National Health and Nutrition Examination Survey 2011-2016 were analyzed. Dental caries was assessed at surface level with the Radike criteria, which matches the case definition of the Global Burden of Disease study. Participants' data were aggregated into 438 groups, based on survey strata and 5-year age brackets, to produce population estimates for the prevalence of untreated caries (DT > 0), DMFT, DMFS, DT, DS, and lifetime caries prevalence (DMFT>0). Conversion formulas were derived using fractional polynomials to characterize the association of each caries indicator with the prevalence of untreated caries.


RESULTS
The mean prevalence of untreated caries was 23.5 percent (SD: 12.9 percent, range: 1.0-72.3 percent). After adjustment for age, the prevalence of untreated caries was correlated with DMFT (r = 0.23), DMFS (r = 0.25), DT (r = 0.74), DS (r = 0.65) and lifetime caries prevalence (r = 0.18). Using fractional polynomial models adjusted for categorical age, the prevalence of untreated caries at population level could be estimated from DMFT with power 1 (linear form), DMFS with power 0.5, DT with power 0.5, DS with powers (0.5; 1) and lifetime caries prevalence with power 1.


CONCLUSION
The prevalence of untreated caries in permanent teeth can be estimated from the DMF index and lifetime caries prevalence. These conversion formulas can facilitate the inclusion of more studies in estimation of the global burden of untreated caries in permanent teeth.