Genetic and other Associations with Dental Caries in Mixed Dentition

Objective:  Dental caries is the most common chronic condition in U.S. children, and evidence suggests the importance of genetic factors, but few genetic studies have been done and none in the mixed dentition.  In this study we assess association between caries and factors including genes in children with mixed dentition.  Methods: From the population-based cohort of families ascertained by the Center for Oral Health Research in Appalachia, we studied 302 children with mixed dentition (6≤age<15) and their parents.  For each study subject detailed dental exams, biological samples, demographics and other data were collected.   The Family Based Association Test (FBAT) tested association between caries and 28 SNPs in 21 candidate genes chosen for involvement in saliva, taste preference, enamel and mineral deposition.  Caries was measured by standard DMFT and DMFS scores, where the score for each child was the sum of the scores for the primary and permanent teeth (males:n=152,age= 0.9±2.7, DMFT=2.8±2.9, DMFS=5.3±7.08; females:n=150, age=10.6±2.6, DMFT=2.4±2.8, DMFS=4.4±6.4).  The scores defined three phenotypes: “any caries” (scores>0, n=203), “severe caries” (age-dependent, n=111), and no caries (“scores”=0, n=96). Regression was used to model simultaneously genes, age, gender, S.mutans and saliva flow as predictors of DMFT and DMFS. Results: From FBAT, SNPs in CACNA1A (p-value=0.004), MMP8 (p =0.05), and AMBN1 (p=0.03) were associated with “any caries” and “severe caries”.  SNPs in CACNB2 (p=0.03), KCNN1 (p=0.03), and TAS1R1 (p=0.04) were associated with “no caries”. From regression, a model including saliva flow rate (p=0.04) and the presence of S.mutans  (p=0.003) explained about 8% of the variation in DMFT/DMFS.  Conclusions: We identified multiple genes that are associated with caries in the mixed dentition; some contributing to risk for caries and others to protection against caries.  Further, saliva flow rate and S.mutans explained about 8% of the variation in DMFT/DMFS. NIH Grant #R01-DE014889.