Objective: To evaluate the ability of near-infrared light transillumination (NIR-LT) to detect interproximal enamel and dentinal caries lesions compared to clinical-visual inspection aided by fiber-optic transillumination (FOTI).
Method and materials: From 170 Finnish adolescents aged 15 to 17 years, 5,294 interproximal surfaces of premolars and molars were examined first clinical-visually aided by FOTI (VI+FOTI) using the International Caries Detection and Assessment System (ICDAS) classification. Subsequently, the surfaces were examined using NIR-LT. The extent of lesions was determined using the modified NIR-LT classification based on the Söchtig criteria. For the analyses, data on maxillary and mandibular premolars and molars were combined. Distributions of lesions were presented as frequencies. Differences between VI+FOTI and NIR-LT at the tooth and tooth surface levels were analyzed by chi-square and Fisher exact tests. Sensitivity and specificity of the NIR-LT method to detect any lesion was performed using VI+FOTI as the gold standard.
Results: By VI+FOTI, 92.4% surfaces were classified as sound and by NIR-LT, 88.2%. Enamel caries lesions were found on 7.0% of the surfaces by VI+FOTI and on 11.6% by NIR-LT. Nearly double the number of enamel lesions were identified by NIR-LT for all examined teeth groups, except for mandibular molars where this was 1.3-fold. In 66% of the surfaces, the differences between NIR-LT and VI+FOTI findings were statistically significant (P .001). The sensitivity for all teeth of NIR-LT was 48.4% and the specificity was 91.1%.
Conclusion: Radiation-free NIR-LT method shows considerable potential as a supplementary method for early detection of caries lesions among low-caries prevalence adolescents.