Abstract: Objective: To explore the influence of age on the pain level of orthodontic patients after initial bracket wearing. Methods: A total of 18 adolescents (11-14 years old) and 18 adults (18-25 years old) with straight wire appliance were enrolled in this study. Visual analog scale (VAS) was used to evaluate the effect of age on orthodontic pain at 7 different time points after the first bracket bonding (immediately, 4 h, 12 h, 1 d, 2 d, 3 d, and 7 d). Results: The time effect was significant (F=94.294,P＜0.01), the main effect of age was not significant (P>0.05), and the interaction effect of age and time was significant (F=54.114,P＜0.01). The age-related effects were significant at 4 h, 2 d, and 3 d after the first loading (P<0.01 at 4 h, P<0.05 at 2 d, and P<0.01 at 3 d). Conclusion: Adolescent patients with fixed appliances respond quickly and sensitively to mechanical force, while adult patients respond slowly but more persistently to inflammatory pain after mechanical force.

Key words: orthodontic pain, visual analog scale, age-dependent