Background/Objectives: Appropriate use of a dental mirror (MT) is essential for dental treatment. However, because the mirror image differs depending on the operator’s position, there are few effective tools available to train dental students and inexperienced dentists. To address this issue, a new virtual reality (VR) system was developed. Methods: Eighty-seven participants, including instructor dentists, graduate students, trainee dentists, and dental students from Niigata University, participated in the experiment. The participants manipulated the virtual dental mirror (DM) connected to three-dimensional (3D) control devices while wearing a head-mounted display (HMD) to simulate an intraoral examination and caries removal. The distance between the center of the DM and the caries, area ratio of the caries on the DM, ellipticity of the caries image, and manipulation time were measured and compared between groups. Results: The mean distance between the centers was 1.18 mm for instructor dentists and 1.56 mm for the students (p = 0.003; effect size, 0.48). Instructor dentists demonstrated significantly superior performance in all evaluation categories compared to the other groups. This suggests that the level of clinical experience affected the results. Conclusions: The newly developed VR system can quantitatively and objectively evaluate DM manipulation. Differences in the operator’s clinical experience led to variations in the techniques used for mirror image confirmation and DM manipulation. This VR system enables quantitative feedback by outputting images from the HMD to a monitor. Therefore, it has the potential to evolve into an unprecedented training tool for dental students or trainees.