Abstract: Objective: To study the relationship between aspartate aminotransferase (AST) activities and periodontal tissue remodeling during rapid palatal expansion in adolescents. Methods: Forty-three patients (aged 10.2-12.5 years) were divided into two groups: the control group(21 cases) and the experimental group(22 cases). GCF samples were collected with filter paper strips at 6 time points: before activation, 24 hours, the first week, the second week, the third week, and the fourth week after activation. AST activities were determined by full automatic biochemical analysis. The results were expressed as total AST activities (μU/30s). Results: AST activities were significantly elevated at 24 hours after activation by the Haas appliance, and remained at a high level until the fourth week after activation. Moreover, from 24 hour after activation to the fourth week after activation, AST activities in the experimental group significantly increased. Conclusion: The results suggest that AST activities in GCF reflect the tissues remodeling which occurs in the periodontium to some degree during rapid palatal expansion.

Key words: Palatal expansion technique, Gingival crevicular fluid, Aspartate aminotransferases