Abstract: [Abstract] Objective: To analyze the risk factors of enamel demineralization in orthodontic treatment with fixed appliance. Methods: Examination of enamel demineralization and a questionnaire survey were conducted during and after orthodontic treatment with fixed appliance among 161 patients. The correlations between incidence of enamel demineralization and gender, age, methods for maintaining oral hygiene or eating habits were analyzed by Log-rank Test. Logistic regression was used to analyze the risk factors which result in enamel demineralization. Result: In 3619 teeth of 161 patients, 328 teeth from 75 patients had enamel demineralization and the incidences were 46.6% and 9.1% respectively. The incidence of enamel demineralization were correlated with age (P=0.038), daily toothbrushing frequency (P=0.001), single toothbrushing time (P＜0.0001) and weekly intake of sweets or carbonated drinks (P=0.015), whereas no significant associations were determined between incidence of enamel demineralization and gender (P=0.386), use of orthodontic toothbrush (P=0.498), fluoride toothpaste (P=0.217) or mouthwash (P=0.170). Logistic regression analysis revealed that daily toothbrushing frequency (P=0.005), single toothbrushing time (P＜0.0001) together with weekly intake of sweets or carbonated drinks (P=0.026) were identified as risk factors of enamel demineralization in orthodontic treatment with fixed appliance. Conclusion: Enamel demineralization is a frequent complication in orthodontic treatment with fixed appliance. Controlling intake of sweets or carbonated drinks reasonably and sufficient toothbrushing frequency and time are important measures to prevent enamel demineralization.

Key words: Orthodontic fixed appliance, Enamel demineralization, Risk factors