Background: The paradigm shift towards the nonsurgical management of dental caries relies on the early detection of the disease. Detection of caries at an early stage is of unequivocal importance for early preventive intervention. Objective: The aim of this in vitro study is to evaluate the performance of a visual examination using the International Caries Detection and Assessment System (ICDAS) criteria, two quantitative light-induced fluorescence (QLF) systems - Inspektor™ Pro and QLF-D Biluminator™ 2 (Inspektor Research Systems B.V., Amsterdam, The Netherlands) - and a photothermal radiometry and modulated luminescence, The Canary System® (Quantum Dental Technologies, Toronto, Ont., Canada) on the detection of primary occlusal caries on permanent teeth. Methods: A total of 60 teeth with occlusal surface sites ranging from sound to noncavitated lesions (ICDAS 0-4) were assessed with each detection method twice in a random order. Histological validation was used to compare methods for sensitivity, specificity, percent correct, and the area under the receiver operating characteristic curve (AUC), at standard and optimum sound thresholds. Interexaminer agreement and intraexaminer repeatability were measured using intraclass correlation coefficients. Results: Interexaminer agreement ranged between 0.48 (The Canary System®) and 0.96 (QLF-D Biluminator™ 2). Intraexaminer repeatability ranges were 0.33-0.63 (The Canary System®) and 0.96-0.99 (QLF-D Biluminator™ 2). The sensitivity range was 0.75-0.96 while that of specificity was 0.43-0.89. The AUC were 0.79 (The Canary System®), 0.87 (ICDAS), 0.90 (Inspektor™ Pro), and 0.94 (QLF-D Biluminator™ 2). Conclusion: ICDAS had the best combination of sensitivity and specificity followed by QLF-D Biluminator™ 2 at optimum threshold.