In the present study, the results that patients with periodontitis had higher CYP27B1 expression in hGFs indicated that patients with periodontitis had a more active vitamin D pathway in hGFs, which further supported this possibility.In the present study, subjects matched by age and gender were included in the two groups and all were non-smokers, in order to minimize the influence of potential confounding factors. The gene discussed is CYP27B1; the disease is periodontitis.