INTRODUCTION: In this prospective study, we compared differences in the diagnosis and treatment planning of impacted maxillary canines between 2 imaging modalities. METHODS: Twenty-five consecutive impacted maxillary canines were identified from the pool of patients seeking orthodontic treatment. The first set of radiographs consisted of traditional 2-dimensional (2D) images including panoramic, occlusal, and 2 periapical radiographs. The second set comprised prints of 3-dimensional (3D) volumetric dentition images obtained from a cone-beam computed tomography (CBCT) scan. Seven faculty member completed a questionnaire for every impacted canine and diagnostic radiographic modality (2D and 3D). RESULTS: The data show that the judges produced different decisions regarding localization depending on the x-ray method. There were 21% disagreement (or discordance) in the perceived mesiodistal cusp tip position and 16% difference in the perceived labiopalatal position. In the perception of root resorption of adjacent teeth, there was 36% lack of congruence. Twenty-seven percent of the teeth that were planned to be left, recovered, or extracted with the 2D radiographs had different treatment plans when the judges viewed the 3D CBCT images (McNemar test, chi-square, 4.45; P = 0.035). The clinicians' confidence of the accuracy of diagnosis and treatment plan was statistically higher for CBCT images (P <0.001). CONCLUSIONS: These results showed that 2D and 3D images of impacted maxillary canines can produce different diagnoses and treatment plans.