According to the Global Burden of Disease Study in 2017, oral diseases affect approximately 3.5 billion people worldwide, with dental caries being the most common condition. In children, especially those aged 6 to 12 years, dental caries can cause pain, difficulty eating, and disrupted sleep, adversely affecting their overall quality of life and development. Therefore, there is a critical need for effective preventive and management strategies for dental caries in this age group.

Vitamin D is a fat-soluble vitamin primarily known for its role in calcium and phosphate homeostasis and bone health. However, recent research has highlighted its pleiotropic effects, particularly its influence on the immune system. The active form of Vitamin D, 1,25-dihydroxyvitamin D, has been shown to modulate both innate and adaptive immune responses, including the production of antimicrobial peptides such as cathelicidin and defensins, which help maintain the microbial balance of mucosal surfaces. In the context of oral health, Vitamin D may contribute to a reduction in cariogenic bacteria through several mechanisms. Firstly, it promotes the expression of antimicrobial peptides in salivary glands and oral epithelium. Secondly, it enhances the oral mucosa’s physical barrier function and immune surveillance, thereby limiting bacterial colonization. Thirdly, studies have reported an inverse relationship between serum Vitamin D levels and dental caries prevalence in children and adults.