The time to first failure, the position of band failure at deband, and the change in enamel white spot lesions of teeth bonded with a modified composite or a conventional glass ionomer were compared in a randomized half-mouth trial over the full course of orthodontic treatment. One hundred forty band pairs were cemented in 98 subjects. Overall band failure rates of 5% and 2.8% were recorded for the modified composite and the conventional glass ionomer, respectively, with no significant difference found between their times to first band failure. At the end-of-treatment deband, the position of band failure was predominantly at the enamel-cement interface for the modified composite and at the band-cement interface for the conventional glass ionomer (P < .001). A comparison of changes in mean enamel white spot lesion scores during treatment did not reveal significant differences between the cement groups (P=.16).