Effect of Different Lighting Conditions on Proximal Caries Detection in Dental School Settings

Abstract

Introduction: Environmental factors, including ambient light, play an important role in caries detection. Dental private practices and dental school clinics are exposed to extraneous light from fluorescent fixtures, operative unit lights and/or windows. In previous studies, visual fatigue and impaired diagnostic accuracy are found to be associated with the viewing conditions. Aim: The study aims to evaluate and compare dental students’ performance at detecting proximal caries on intraoral digital radiographs, under different ambient light conditions. Materials and Methods: Eight randomly chosen senior dental students and a dentist evaluated intraoral digital images of 32 extracted teeth mounted in 12 quadrants. Almost half of the teeth were carious as confirmed by histology. The illuminance measuring unit (Lux) was used to measure the light conditions at luminous flux per unit area. Raters viewed the images in ambient light conditions i.e., dim light settings (Less than 50 Lux) and in bright light settings (more than 800 Lux). Images were viewed with the same calibrated monitor. All other viewing conditions were controlled. Raters stated their certainty of caries presence on a 5-point scale. Sensitivity, specificity and Receiver Operating Characteristic (ROC) curve was calculated for all observations and for both light settings. Results: Raters performed at a higher specificity under dim light conditions (p<0.05). ROC analysis showed that the overall performance under dim light environment was better than the bright light environment (0.745 vs. 0.710), which was statistically significant (p<0.05). Conclusion: The results support reducing ambient light levels to rule out caries, as there is a significantly higher specificity and performance in a dim light environment compared to bright one.

Keywords

• ambient light
• calibration
• digital radiographs
• illuminance
• photometer