Vitamin D regulates immunity and bone metabolism and plays a significant role in calcium metabolism and homoeostasis.8 25‐Hydroxyvitamin D3 (25(OH)2D3) is the stable condition of VD3 in the body.9, 10 Previous studies have shown that 25(OH)2D3 supplement decreased inflammation factor TNF‐α in monocytes and inhibited the proliferation of T cells.10, 11 Moreover, 25(OH)2D3 ameliorated experimental periodontitis in diabetic mice.12 While it is known that 25(OH)2D3 binds to vitamin D receptor (VDR) to mediates its biological effects, the detailed mechanism of action needs further investigations. This evidence concerns the gene VDR and periodontitis.