The validity of marker registration for an optimal integration method in mandibular navigation surgery

Purpose: The aim of this study was to verify the accuracy of 2 registration methods (marker-based registration and marker-free registration) during mandibular navigation surgery. Materials and Methods: Two point-to-point registration methods (marker-based registration and marker-free registration) were tested using software and navigation equipment: 1) 3 implanted orthodontic screws and 2) 3 anatomic points on the cusp tips of the teeth (central incisor and first molars bilaterally). Results: For the navigation equipment, the 3-point matching method of screw references was more accurate for all anatomic areas except the coronoid process and second premolar alveolar area. The registration error was largest for the condyle area. Errors were larger than 2.0 mm in the condyle, condyle neck, sigmoid notch, coronoid process, posterior border, lingula, and angle areas. In the oblique ridge, mental foramen, and dentoalveolar areas, the registration error using screws was smaller than 1.5 mm. For the software, tooth cusp references were more accurate for anatomic areas such as the mental foramen and dentoalveolar areas, but not the molar area. In all cases, the registration error was smaller than 1.0 mm, and that for the first molar was similar between the tooth tip overlap and the screw overlap. Conclusions: Registration using screws generally was more accurate than registration using tooth cusps for mandibular navigation surgery. However, tooth tip references can be used for registration in dentoalveolar surgery.