Computerised dental trainers coming closer to simulating actual teeth
MACAU SAR: The term “haptics” means “relating to the sense of touch”. Haptic perception strongly relies on the forces experienced during touch and movement. While touch is considered to be the earliest sense to develop after birth, it is the least understood sense compared with other sensory modalities such as sight and hearing.*
Dental education is a discipline in which a significant proportion of preclinical training requires trainees to depend primarily on tactile sensations to achieve a high level of precision. This makes haptics ideally suited for all kinds of dental training systems that will teach, provide practice in and improve tactile skills. Addition of haptics to dental training simulators is very important because it allows trainees to feel what the instructor is feeling.
The ideal dental training simulators should provide sensations similar to those felt when executing the same procedure on a real tooth. Manikin-based dental training simulators, such as DentSim, allow procedures to be performed using real dental instruments; therefore, tactile feedback involved in simulated procedures is naturally provided.
However, most manikin-based dental simulators use only disposable plastic teeth for training.
While manikins and their plastic teeth are becoming more realistic and coming closer to simulating the real feel of actual teeth, it is still difficult to provide the level of detail and material properties of real teeth (enamel, dentine, pulp, or carious lesions). Using real teeth with such systems might be possible, but there are still problems regarding availability of extracted teeth in various conditions, rules and regulations about how they can be used, and standardisation.
The alternative dental simulation currently being developed and investigated by few research groups is haptic-enabled virtual reality dental training. In this kind of system, the trainee holds a haptic device stylus, which is a virtual representation of real dental tools and executes movements over virtual models of projected or on-screen human teeth. The simulator feedback represents topological changes in the tooth structure and forces in the hand of the trainee, which makes it possible to feel what is on a computer monitor or a projected image. Some of these simulators use reconstructed virtual teeth from CT images of real teeth to simulate the tissues that form the tooth structure or even caries. However, simulating realistic force sensations for different dental materials, instruments, and procedures is very challenging and still an active area of research. Force-computing techniques currently used vary from basic spring force models to sophisticated methods involving CT density value and torque.
Commercially available haptic virtual reality dental training systems include Simodont Dental Trainer (Moog) and VOXEL-MAN Dental.
There is still room for improvement for both types of simulator in terms of haptic sensation. The manikin-based simulators will benefit from much more realistic plastic teeth that are not prohibitively expensive, and the virtual reality simulators need a novel, high-fidelity force-computing algorithm.