The aim of this laboratory study was to evaluate the effectiveness of incorporating radiographic examination and DIAGNOdent with visual examination for the detection and treatment of noncavitated occluso-dentinal caries. Four examiners examined the occlusal surfaces of 160 extracted posterior teeth. Teeth were examined three times with a one-month interval in between. The first examination was visual (V), the second examination was visual with radiograph (VR), and the third examination was visual with radiograph and DIAGNOdent (VRD). Examiners were asked to detect the presence of caries (if any) and identify the extent of caries (if present; ie, enamel or dentin). The examiners were also asked to choose a treatment for each tooth. The examined teeth were later sectioned, and the presence of caries was charted as 0 = no caries, 1 = caries confined to enamel, 2 = caries in the outer dentin, and 3 = caries in the inner dentin. Sensitivity, specificity, area under the curve (Az values), rank correlation coefficient, interexaminer reproducibility, and McNemar χ(2) tests were calculated. VR had statistically higher specificity and lower sensitivity than V and VRD. The means of Az values ranged from 0.58 to 0.63, with no statistical difference between the three examinations (p>0.05). The means of the rank correlation coefficients with histology for detection of dentinal caries were 0.48, 0.23, and 0.44 using V, VR, and VRD, respectively. Interexaminer reproducibility was best for V alone. The percentages of teeth indicated for restorative treatment were 31%, 33%, and 41% using V, VR, and VRD, respectively. The percentages of teeth correctly treated according to histology were 69.4%, 70.0%, and 67.5% using V, VR, and VRD, respectively. There was no difference in the accuracy of treatment decisions between the three examination points (p>0.05). The addition of radiographs and DIAGNOdent to visual examination did not have a significant effect on the improvement of the detection or treatment decisions of examiners of noncavitated occluso-dentinal carious lesions.