In vitro performance of near infrared light transillumination at 780-nm and digital radiography for detection of non-cavitated approximal caries.

OBJECTIVES: To evaluate the ability of a Near Infrared Light Transillumination (NILT) device to detect non-cavitated approximal caries lesions; and to compare its performance to Digital Radiography (DR).

METHODS: Thirty human extracted premolars (sound to lesions into the outer one-third of dentin) were selected. Lesion depth was confirmed by micro-computed tomography (μ-CT). Teeth were mounted in a custom-made device to simulate approximal contact. DR and NILT (CariVu™, DEXIS, LLC, Hatfield, PA, USA) examinations were performed and repeated by three trained and calibrated examiners. Sensitivity, specificity, area under ROC curve (Az ), inter- and intra-class correlation coefficients (ICCs) for each method, and correlation among the methods were determined.

RESULTS: ICCs for intra-/inter-examiner agreement were substantial for NILT (0.69/0.64), and moderate for DR (0.52/0.48). Sensitivity/specificity for NILT and DR were 0.68/0.93 and 0.50/0.64, respectively. Az for NILT was 0.81, while for DR it was 0.61. Spearman correlation coefficient with μ-CT for NILT (0.65, p<0.001) demonstrated moderate association, while that of DR suggested no association (0.19, p=0.289).

CONCLUSION: Within the limitations of this in vitro study, NILT demonstrated a potential for early approximal caries detection. NILT and DR performed the same regarding the accuracy for non-cavitated approximal caries detection; however, NILT was superior to DR in terms of repeatability, agreement and correlation with μ-CT.

CLINICAL SIGNIFICANCE: A commercial version of NILT was recently introduced as a non-irradiative adjunctive caries detection method. It uses near infrared (NIR) light at 780-nm to transilluminate teeth and captures live images from the occlusal surface. This study demonstrates that NILT can be used as an alternative to radiography for non-cavitated approximal caries detection.