Development of a Training Simulator for Caregivers? Toothbrushing Skill Using Virtual Reality

Oral care is key to maintaining overall health. Elderly people and people with disabilities who re-quire nursing care can have difficulty in brushing their teeth effectively and may require the assistance of a care-giver. However, to date, an effective method for teaching toothbrushing skills to caregivers and a training sys-tem that can be implemented in a non-in-person setting have not been established. Therefore, in this study, we developed a training simulator that enables skill acquisition while learning ideal brushing motion and force in-formation from an arbitrary viewpoint in a virtual reality (VR) space. In this simulator, the position and orien-tation of the toothbrush as measured by six infrared cameras and the brushing force as measured by a small 6-axis force sensor are displayed in a VR space using computer graphics to match the visual information in the VR space with hand-force information in real space. The experiment was conducted in 10 healthy adults with no specialized skills or knowledge regarding oral care. They were trained to brush the cervical and distal parts of the maxillary central incisors while learning the ideal brushing motion shown by the computer graphics and the appropriate range of brushing force. Afterwards, skills were quantified in terms of brushing motion, brush-ing force, and plaque removal rate, and the overall effectiveness of the training was evaluated. The results showed that in cervical part brushing, the mean error between the participants' brushing motion and the ideal brushing motion in the brushing direction improved from approximately 4.8 mm before training to 3.9 mm af-ter training. In distal part brushing, the error improved from approximately 3.8 mm to 1.9 mm. Similarly, brushing force improved from approximately 0.8 N before training to the appropriate force of 1.5 N after train-ing for both cervical and distal part brushing. The artificial plaque removal rate improved from 40.3% to 68.7% for cervical part brushing and from 39.5% to 63.3% for distal part brushing, indicating the effectiveness of training using the proposed system. This simulator, which can simultaneously teach both brushing motion and brushing force, is expected to be developed as a new method for teaching toothbrushing skills to caregivers.