Abstract: ObjectiveTo explore the expression of osteoprotegerin(OPG), interleukin-35(IL-35) and interleukin-37(IL-37) in chronic periodontitis and their correlation with alveolar bone resorption. 
MethodsIn total, 105 patients with chronic periodontitis were selected as the experimental group, 45 patients with chronic periodontitis were selected as the verification group, and 105 patients undergoing physical examination were selected as the control group. The levels of OPG, IL-35 and IL-37 in the gingival crevicular fluid of the experimental group and the control group were compared. The proportion of alveolar bone resorption in patients with different clinical characteristics in the experimental group was compared. The influencing factors of resorption ratio of the alveolar bone in the experimental group were analyzed. A multiple linear regression model was established. 
ResultsThe levels of OPG and IL-37 in gingival crevicular fluid of the experimental group were lower than those of the control group, while the level of IL-35 was higher than that of the control group(P＜0.05). The results of multivariate linear regression analysis showed that the levels of OPG, IL-35 and IL-37 in gingival crevicular fluid were the influencing factors of resorption ratio of the alveolar bone(P＜0.05). The regression model was established as follows: Resorption ratio of the alveolar bone=6.495-0.180×OPG+0.169×IL-35-0.055×IL-37. The independent variable could explain the 91.5% variation of resorption ratio of the alveolar bone. The regression model was validated with the OPG, IL-35, and IL-37 levels in the patients′ gingival crevicular fluid in the verification group, and the mean absolute deviation(MAD) value was 1.25%. 
ConclusionThe expression of OPG and IL-37 in the gingival crevicular fluid of patients with chronic periodontitis is low, and the expression of IL-35 is high. The three are closely related to alveolar bone resorption.

Key words: chronic periodontitis, osteoprotegerin, interleukin-35, interleukin-37