The Impact of 3D Stereopsis and Hand-Tool Alignment on Effectiveness of a VR-based Simulator for Dental Training

Recent years have seen the proliferation of VR-based dental simulators using a wide variety of different VR configurations. Differences in technologies and setups used result in important differences in degree of realism. These include 3D stereoscopic rendering and visual alignment of the user's hands with the virtual tools. While each new dental simulator typically is associated with some form of evaluation study, only few comparative studies have been carried out to determine the benefits of various simulation aspects. In this paper, we seek to determine the impact of 3D stereoscopic rendering and of hand-tool alignment on the teaching effectiveness of a VR dental simulator. We developed a bimanual simulator using an HMD and two haptic devices that provides an immersive environment with both 3D stereoscopic rendering and hand-tool alignment. We then systematically and independently controlled for each of the two aspects of the simulation. We trained four groups of students in root canal access opening using the simulator and measured the learning gains by doing pre- and post-testing using realistic plastic teeth. We found that hand-tool alignment has a positive impact on learning gains, while stereoscopic 3D does not. The effect of stereoscopic 3D is surprising and demands further research in settings with small target objects. The results of our study provide valuable information for the future design of dental simulators, as well as simulators for other high-precision psycho-motor tasks.