With the increasing use of digital radiography, the display parameters of the devices used to view radiographs have become important factors in caries detection. Interest in the use of tablet devices for this application has increased due to their availability, portability, and ease of use. However, to be effective in clinical situations, these portable devices must have displays that perform well under multiple lighting conditions and at different angles. The purpose of this study was to assess the utility of the iPad with Retina Display for the detection of Class II caries under common overhead lighting conditions. The device was used in both standing and angled positions by 5 reviewers, and their diagnoses of caries were compared to the diagnoses the same reviewers made using a thin-film transistor flat-panel display (TFT-FPD) in dim lighting conditions. Histological analysis was used as the gold standard to confirm the presence or absence of caries. In a standing position, the tablet device performed as well as the TFT-FPD. When used in the angled position, the tablet performed slightly worse than the TFT-FPD. The findings suggest that if the user can compensate for overhead glare, the tablet device may perform as well as a calibrated, upright display in a dimly lit room.