Purpose: The purpose of this study is to quantify the depth of enamel cracks using Quantitative light induced fluores cence-digital (QLF-D) and swept source optical coherence tomography (SS-OCT), and to compare the validity of detection methods. Methods: A total of 80 extracted teeth with cracks in the coronal portion or suspected cracks were selected. First, the non destructive devices QLF-D and SS-OCT were taken, and then histological evaluation was performed. Cracks was divided into 4 types with depth of the crack: Sound, Initial crack, Moderate crack, and Dentin-enamel junction (DEJ) crack. Results: As a result of the validity of the crack depth, the SS-OCT showed the highest sensitivity for detecting initial cracks at 0.98, and the lowest sensitivity for detecting DEJ cracks at 0.70. When detected with QLF-D, the cut-off value of the maximum fluorescence loss for detecting initial cracks was 5, and showed a sensitivity and a specificity of 1.00. Conclusions: The application of SS-OCT and QLF-D in diagnosing cracked teeth will not only be effective in detecting early stage cracks, but will also help to establish an appropriate treatment plan for crack progression.