The purpose of this study was to help predict the enamel thickness of mandibular incisors. At least two direct digital periapical radiographs were made for each of the 80 subjects. Radiographs were scaled to control for magnification errors using dental study models and computer software. Mesiodistal incisor width and mesial and distal enamel thicknesses were measured. Lateral incisors were determined to be wider than central incisors and distal enamel thicknesses were larger than mesial enamel thicknesses on average. The African American group demonstrated wider incisors and enamel thicknesses than the Caucasian group on average. Enamel thickness positively correlated with tooth width for all incisors. No statistically significant differences were detected between male and female groups. Some conclusions relating to enamel thickness can be made based on race, incisor position, and incisor width, but correlations were not considered strong enough to accurately determine enamel width, without the aid of radiographs.