Objective: To evaluate the clinical performance of impedance spectroscopy, laser fluorescence, and bitewing radiographs in detecting occlusal caries and compare them with visual scores. Method and Materials: In 62 adults, one occlusal surface per person was selected and independently examined by two examiners using the visual ICDAS scoring system, CarieScan PRO (ACIS), DIAGNOdent pen (LF-pen), and bitewing radiographs. The procedures were repeated within 1 to 4 weeks. The diagnostic performance was expressed as sensitivity, specificity, predictive values, accuracy, and diagnostic odds ratio (DOR) using ICDAS as gold standard. Intra- and inter-examiner reproducibility was assessed with intra-class correlation coefficients (ICC) for numerical results and kappa values for categorical data. Five patients dropped out due to no-shows or restorative care. Results: In total, 54% of the teeth had early or no lesions (ICDAS 0 to 2) while 46% exhibited moderate to extensive lesions (ICDAS 3 to 5). The Spearman correlation coefficients were 0.65, 0.60, and 0.71 for ICDAS vs ACIS, LF-pen, and bitewing radiographs, respectively. ACIS demonstrated high specificity and positive predictive values but low sensitivity, whereas LF-pen had moderate sensitivity and high specificity. Accuracy and DOR was highest for bitewing radiographs. The ICC values ranged between 0.65 and 0.88 for ACIS and 0.89 and 0.94 for LF-pen. The weighted kappa values were 0.81 to 0.91 for ICDAS and 0.90 to 0.92 for bitewing radiographs. Conclusion: All three methods were useful for detecting occlusal caries but bitewing radiography exhibited the best performance when compared with visual scoring. ACIS displayed the highest specificity and positive predictive value but the sensitivity was low and the clinical handling was less convenient. Further clinical studies are needed to evaluate the long-term effects of early caries detection on dental health. Keywords: adults, caries detection, ICDAS, impedance spectroscopy, laser fluorescence, radiographs