A cross-sectional study was carried out to determine the prevalence and severity of enamel opacities occurring on different surfaces of the dentition as well as the distribution of these lesions on individual teeth following orthodontic treatment. The sample consisted of 527 patients examined prior to and 269 other patients examined after completion of multibanded orthodontic treatment. The results showed that following orthodontic treatment there was a significant increase in the prevalence of enamel opacities on the vestibular and lingual surfaces of the dentition. The increase was significantly greater on the cervical and middle thirds of the crown. Among individual teeth, there was a statistically significant increase in the prevalence and severity of enamel opacities on the maxillary and mandibular first molars, the maxillary lateral incisors, and the mandibular lateral incisors and canines. The increase was greatest on the cervical and middle thirds of the vestibular surface of these teeth.