Effect of ambient light level at the monitor surface on digital radiographic evaluation of approximal carious lesions: an in vitro study.

OBJECTIVES This study investigated how ambient light affects the diagnostic accuracy of dental carious lesions on monitors used in dental practice. Specifically, the aim was to evaluate whether a monitor hood for blocking excess ambient light increases practitioners' ability to accurately diagnose carious lesions on digital radiographs under bright ambient light conditions. METHODS 7 observers evaluated approximal carious lesions on standardized digital radiographs of 100 teeth under 3 ambient light conditions: bright light (> 1000 lx) and dim light (<50 lx) with no monitor hood; and bright light with a hooded monitor. Receiver operating characteristic curves were plotted for all observations. The criterion standard was a histological examination of the teeth. A paired t-test compared the effects of the three lighting conditions. The level of significance was set to p <0.05. Weighted kappa statistics estimated intraobserver agreement. RESULTS The diagnostic accuracy for dentine lesions was significantly higher in ambient light<50&hairsp ;lx than on monitors with and without a hood in ambient light>1000 lx. For all observers, diagnostic accuracy of dentine lesions under bright light was higher on a hooded monitor than on a monitor without a hood, but this difference was not significant. Intraobserver agreement varied from moderate to good. CONCLUSION Diagnostic accuracy of those carious lesions that reached into the dentine was significantly higher in ambient light<50 lx than in ambient light>1000 lx. A hooded monitor in bright light was not as effective as a monitor without a hood in dim light.