Caries Detection in Anterior Teeth Using Lateral NIRT at 1300nm

Objectives: The aim of this in vitro study was to assess lateral near-infrared transillumination at 1300 nm (NIRT1300) for proximal caries detection in permanent anterior human teeth and to compare it with direct proximal visual inspection using ICDAS and digital bitewing radiography (BWR).
Methods: Eighteen extracted permanent anterior teeth with sound or carious proximal surfaces were visually assembled and assessed using ICDAS in direct view, BWR and NIRT1300. The NIRT1300 was passed through the samples in a horizontal direction. Corresponding proximal surfaces were assessed from the lingual and buccal sides one time by two examiners. Two examiners each assessed the surfaces in one session based on yes/no decisions regarding the presence of carious lesions for BWR and NIRT1300.
Micro-computed tomography served as reference standard. Statistical analysis included cross-tabulation and calculation of overall accuracy, sensitivity and specificity.
Results: A total of 32 filling-free proximal surfaces in 18 anterior teeth were assessed. These surfaces were 15.63% sound (code 0), 53.13% had signs of initial or established lesions (codes 1 and 2) and 31.25% had cavitations according to ICDAS. The overall accuracy was 65.63% for BWR, 71.88% for ICDAS and 84.38 % for NIRT1300. Underestimation of caries was 34.38% for BWR and 9.38% for NIRT1300. There was no overestimation of caries according to BWR, while NIRT1300 exhibited 6.25%. Sensitivity values were 38.89% for BWR and 83.33% for NIRT1300. Both methods revealed high specificity, with 100% for BWR and 85.71% for NIRT1300.
Conclusions: Lateral NIRT1300 revealed comparable or higher diagnostic results than ICDAS and BWR for proximal caries detection. Lateral transillumination of the anterior dentition seems to be a promising new methodology to complement visual inspection and BWR as diagnostic instrument.