In vivo validation of near-infrared light transillumination for interproximal dentin caries detection

The aims of this clinical study were to investigate the diagnostic accuracy of near-infrared light transillumination (NILT) as a novel X-ray-free method for proximal dentin caries detection and to compare this method to established diagnostic methods.

A total of 127 interproximal dentin caries lesions without any cavity within visible dentin in posterior teeth from 85 consecutively selected patients were included. Visual and radiographic diagnoses and laser fluorescence measurements were available. NILT images were obtained, and a dentin lesion was predicted if a demineralisation involved the enamel-dentin junction (NILT-EDJ) or a shadow in dentin was detectable (NILT-dentin). Included lesions were opened and validated (reference standard). The statistical analyses included descriptive analyses and calculations of sensitivity, specificity and Az values.

The diagnostic accuracy with respect to the reference standard was 1.6% for visual inspection, 66.7% for laser fluorescence, 96.1% for digital radiography, 29.1% for NILT-dentin and 99.2% for NILT-EDJ. Bitewings (Az 0.984) and NILT-EDJ (Az 0.992) performed equally.

Given the lack of true negatives in the study, the diagnostic accuracy of NILT achieved the same level as bitewings for the detection of proximal dentin caries.

This study might indicate that NILT could reduce the usage of bitewings.