The purpose of this study was to compare the detection rate of root canal orifices by three different methods: naked eye, with surgical loupes, and under a microscope. Two undergraduate dental students located the orifices of 260 teeth by using the above-mentioned methods. Then, India ink was injected into the pulp chamber and all teeth were cleared to determine the actual number of the orifices. There was a significant difference in the detection rate among the three methods (p < 0.01, chi-square test); the microscopic method could more accurately detect orifices than the others could. Surgical loupes were relatively ineffective compared with the microscopic method for detecting orifices.