The effect of camera and display technology on the reliability of digital shade evaluation

Introduction: For a successful prosthodontic rehabilitation, accurate and economic shade selection methods are warranted. Shade selection with digital cameras and various commonly used digital displays can be suggested as an alternative to expensive colorimetric instruments and inaccurate visual shade selection. To digitalize prosthetic rehabilitation, standards need to be set on minimum digital specifications required to capture and communicate accurate shade selection. This study aimed to establish a minimum specification required for a digital image, to achieve the most accurate result in prosthodontic shade selection, using digital photography. Materials and Methods: A cross-sectional study was conducted among 100 dental professionals with normal color vision. Sixteen shade tabs were randomly selected from two commonly used shade guides and were photographed using four different commonly used digital cameras under standardized settings. After dividing the shade tabs into four groups randomly, the images were displayed on four different outputs. Participants were made to match the outputs to a complete set of shade guide. Descriptive statistics were used to assess the proportion of correct responses. Chi-square test was used to test for the presence of statistical association between the groups. Results: For digital shade evaluation, output from the compact camera (Nikon Corporation, Tokyo, Japan) with an effective output of 14 megapixel showed higher number of responses in terms of accuracy, in comparison with other devices which produced digital outputs with a higher pixel density. The shades were identified best on outputs with a higher pixel density of 2560 × 1600-pixel resolution, followed by full HD LCD display (1920 × 1080-pixel resolution). Conclusion: This study recommends digital photography using a 14-MP camera as a minimum specification for shade selection. For display outputs, laptops with a screen resolution of at least 1920 × 1080, calibrated in standard red, green, blue color space is recommended for visual shade selection.