Proper mineralization of teeth, bones, and other calcified tissues relies on vitamin D, which regulates calcium and phosphate homeostasis. The vitamin D receptor (VDR) gene must be activated for vitamin D to exert its effects. This research aimed to explore the influence of serum vitamin D levels and VDR gene variations on the development of dental caries in children. A total of 128 children aged 3–6 years participated, split evenly into two groups: 64 caries-free and 64 with dental caries. Blood samples were collected to quantify serum 25-hydroxyvitamin D concentrations. Oral examinations were performed to determine dmft index scores. For genetic assessment, 26 children (13 from each group) underwent PCR amplification and Sanger sequencing to detect variations in the VDR gene. Data analysis included chi-square or trend tests for categorical variables, Student’s t-test or Mann–Whitney U test for continuous variables depending on normality, and Kruskal–Wallis tests for comparisons among three or more non-normally distributed groups. Children with caries generally had lower serum vitamin D levels than their caries-free counterparts, but this difference did not reach statistical significance. No mutations in the VDR gene were observed in either group. Furthermore, the frequency of ApaI, TaqI, and FokI polymorphisms was similar between groups. These outcomes indicate that routine vitamin D supplementation may not be effective as a preventive strategy against dental caries. The study sheds light on the interplay between vitamin D, VDR genetic variants, and dental caries in preschool-aged children. These findings contribute to understanding potential risk factors for oral health and may guide the design of future preventive measures, though additional research is required to clarify the role of vitamin D.
