The aim of this study was to investigate the levels of the oxidant and antioxidant changes in orthodontic tooth movement and the effects of vitamin E on these parameters. For this purpose, 50 orthodontic patients (aged 1318?years) required non-extracted treatment were divided randomly into the following groups: Control and Vitamin E. Same pre-adjusted appliances were applied to all patients, and vitamin E (300?mg?day-1) was given during 1?month in vitamin E group. Gingival crevicular fluid was collected and periodontal indexes were recorded at the baseline and after 1?month. Lipid peroxidation (LP) levels as malonyldialdehyde, reduced glutathione (GSH) and glutathione peroxidase (GSH-Px), vitamin C and E levels were measured in the anterior and posterior regions of the dentition. After 1?month, orthodontic treatment LP levels increased in control group in both anterior and posterior regions in vitamin E group. LP levels also increased in vitamin E group in only posterior region. The level of GSH and vitamin C did not change statistically in control and vitamin E groups. Periodontal indexes did not show any differences in comparison with the groups. In conclusion, we observed protective role of vitamin E on LP levels in anterior region of patients with orthodontic tooth movement. Copyright (C) 2011 John Wiley & Sons, Ltd.