Virtual Stigmometer Widget (ViSti) for Precise 5DOF Dental Drill Tool Positioning with Augmented Reality

Dental tool positioning is a challenging manual operation that requires precise 5DOF positioning of the drill -rotation around the tool is not influential- minimal error can result in grave consequences such as nerve and bone damage. Augmented Reality (AR) can help to assist tool positioning, but the widgets proposed in the literature are quasi-static, commonly using virtual 3D cylinders or lines to be visually collimated and eventually supported by color change. We draw our inspiration from the photographic viewfinder and propose a novel Virtual Stigmometer Widget (ViSti) to convey tool positioning error magnitude to the dentist. The widget slightly blurs the view and gradually focuses it while approaching the target (i.e., implant drilling position) till it is perfectly collimated. We conducted a within subjects experiment (N = 30) to compare our widget with the golden standard in 32 positioning tasks. NASA-TLX results demonstrated that our widget reduces frustration (−43%), and mental demand (−19%), and the user perceives a better performance (+8%). However, the expected tradeoff is effort (+34%), and physical (+33%) temporal demand (+4%). Our widget demonstrated to have a potential usage for dentistry and in further fields where 5DOF precision is crucial.