The sample consisted of 180 boys aged 6–8 years. According to their body mass index (BMI), children were assigned to three groups of 60 boys (normal weight, overweight, and obese). Moreover, within each weight group, the sample was divided into three groups according to caries severity (20 children in each group): mild (dmft ≤ 3), moderate (dmft = 4–6), and severe (dmft ≥ 7). Unstimulated whole saliva was obtained from each child in the morning (9 : 00–11 : 00 a.m.) at least 1 h after food or drink intake. Participants were seated and asked to accumulate saliva in the floor of their mouth and then spit into sterile, prelabeled polypropylene tubes over a 5 min period; the samples were then analyzed to assess salivary vitamin D, calcium, and magnesium concentrations.

Salivary vitamin D, calcium, and magnesium concentrations were significantly higher in boys with normal weight than in overweight and obese boys ( p ≤ 0.05), the same results were recorded in mild caries children compared to those with moderate and severe caries ( p ≤ 0.05). Interactions between BMI and caries severity in vitamin D, magnesium, and calcium were found that reached significant levels.

This study provides preliminary evidence of associations between salivary (vitamin D, calcium, and magnesium) levels and both dental caries and overweight in boys. Given the cross‐sectional design, limited sample size, and homogeneous population, the results should be interpreted with caution. Longitudinal studies are required to validate these biomarkers for routine clinical use.