Evaluation of detecting proximal caries in posterior teeth via visual inspection, digital bitewing radiography and near-infrared light transillumination

Purpose: This prospectively designed, non-validated in vivo diagnostic study compared the results of visual examination, digital bitewing (BW) radiography and near-infrared light transillumination (NIR-LT, DIAGNOcam) on proximal caries detection in posterior teeth. Methods: A total of 203 subjects (122 men/81 women; mean age, 23.0 years) were included. All subjects were visually examined according to the standards by the World Health Organization and the International Caries Detection and Assessment System. In addition, digital BW radiographs were performed. NIR-LT images were captured from all posterior teeth. All BWs and NIR-LT images were blindly evaluated for the presence of enamel caries lesions (ECLs) and dentin caries lesions (DCLs). No histological validation was performed due to the impossibility to investigate healthy surfaces and non-cavitated caries lesions invasively. The statistical analysis included both descriptive and exploratory data evaluations. Results: The diagnostic outcome differed for each method. Compared with BW radiography (8.0 surfaces) and NIR-LT (10.5 surfaces), visual examination revealed the fewest caries-related findings (4.2 surfaces). BW radiography or NIR-LT detected either 86.2% or 89.6% of all ECLs/DCLs in posterior teeth alone. When combining visual examination with NIR-LT, 70.9% of all ECLs/DCLs were similarly detected; when visual examination and BW radiography were combined, this proportion was lower (52.6%).