Abstract Objectives: The purpose of this study was to determine the esthetic importance of different types of developmental enamel defect. Methods: In the first method used, individual subjects from three different populations with less than 0.1, 0.7, and 0.9 ppm fluoride in their drinking water, were asked about the appearance of their teeth and results compared to assessments of clinical photographs made by a single examiner. In the second method used, dentist and lay observers were asked to assess the appearance of the dentition of selected individuals who had a range of enamel defects. Results: According to the first method, both the size of demarcated opacities and the degree of enamel hypomineralization (TF index) were related to satisfaction with appearance. However, there was no difference in satisfaction with the appearance of the teeth among the three areas included in this study. In the second method, similar types of enamel defects were found to be esthetic stimuli as with the first study, but the dentists responded more strongly to the stimulus of enamel hypomineralization than the lay examiners. Conclusions: Both demarcated opacities and enamel hypomineralization may be important when assessing differences between populations. Further, esthetic ratings by dentists may not be a suitable means of assessing the esthetic importance of different types of enamel defects.