In vitro visual and visible light transillumination methods for detection of natural non-cavitated approximal caries

ObjectivesThe objective was to evaluate a visible-light-transillumination (using Digital Imaging Fiber-Optic Transillumination machine: DIFOTI) method using occlusal view (DIFOTI-occl), axial view (buccal and lingual: DIFOTI-axial), and combination of all views (DIFOTI-all) for detecting non-cavitated approximal caries and to compare its performance to visual examination (International Caries Detection and Assessment System: ICDAS).Materials and methodsThirty extracted human premolars were selected (sound to lesions into the outer one-third of the dentine) based on micro-computed tomography (-CT). Teeth were mounted in a custom-made device to simulate approximal contact. DIFOTI (Electro-Optical Sciences Inc., Irvington, NY, USA) images were obtained from the occlusal, buccal, and lingual views. DIFOTI image and ICDAS examinations were performed and repeated by three trained/calibrated examiners. Sensitivity, specificity, area under receiver operating characteristics curve (A(z)), inter- and intra-class correlation coefficients (ICCs), and correlation were determined.ResultsSensitivity/specificity was for DIFOTI-occl: 0.42/0.75, DIFOTI-axial: 0.86/0.93, DIFOTI-all: 0.91/0.69, and for ICDAS: 0.89/0.83. A(z) for DIFOTI-occl was significantly lower than that of DIFOTI-axial (p<0.001), DIFOTI-all (p=0.002), and ICDAS (p=0.005). Spearman correlation coefficients with -CT for DIFOTI-occl (r=0.39) showed weak association, while DIFOTI-axial (r=0.80), DIFOTI-all (r=0.91), and ICDAS (r=0.90) showed moderate association. ICCs for intra-examiner repeatability/inter-examiner agreement were for DIFOTI-occl (0.64/0.58), DIFOTI-axial (0.92/0.89), DIFOTI-all (0.85/0.83), and ICDAS (0.79/0.72).ConclusionsThe results of the current in vitro study suggest that, for detection of non-cavitated approximal caries lesions, DIFOTI performs better using axial than occlusal view.Clinical relevanceApproximal non-cavitated caries detection is challenging. DIFOTI can observe images from occlusal-, buccal-, and lingual views. DIFOTI and visual (ICDAS) examinations of buccal- and lingual- and all-views are more suitable than those of occlusal view for a detection of non-cavitated approximal caries.