Objective: To Study the AST activity in gingival crevicular fluid(GCF) and to evaluate the influence of periodontal healthiness between adult and adolescent during the fixed orthodontic treatment.

• 目的:通过检测龈沟液中天冬氨酸转氨酶(AST)的活性来评价固定正畸对成人和青少年牙周健康的影响。