Fig. 3

Image-to-patient registration strategies in OCMS. A In traditional navigated OCMS, a skull-fixed marker, here using retro-reflective spheres for tracking with an infrared sensor, is used for registration. B Alternatively, using patient-specific occlusal splints for non-invasive marker fixation has been proposed. C Marker-less registration, for example, using a laser scanner to capture the outer anatomy of the patient has also been suggested. However, to track the movement of the patient, a marker is still required [18]