KLK4 and dental caries: While the SNP in KLK4 (rs2978642) was not associated with dental caries in primary dentition (p > 0.05), the A allele and AA genotype SNPs in KLK4 (rs2978642) were associated with dental caries in children with permanent dentition (p = 0.006, OR = 1.46, 95% CI 1.10–1.94, and p = 0.015, OR = 1.53, 95% CI 1.06–2.22).