Thiem Daniel G E, Seifert Lukas, Graef Julian, Al-Nawas Bilal, Gielisch Matthias, Kämmerer Peer W
Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, University Medical Centre Mainz, Mainz, Germany.
Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Goethe University Medical Centre Frankfurt, Frankfurt, Germany.
Int J Med Robot. 2022 Jun;18(3):e2362. doi: 10.1002/rcs.2362. Epub 2022 Jan 10.
Registration is most important in navigation-assisted-surgery including the matching between the coordinates of the actual patient space and the medical image. Marker-based techniques mostly include marker application with subsequent radiography. In the edentulous patient, maker-free methods are generally less accurate and reproducible. This new method of a marker-free registration uses the transverse palatal rugae as registration structures.
(1) Segmentation of bone and hard palatal mucosa from initial 3D imaging (DICOM), (2) Maxillary intraoral-scan with transfer to the 3D imaging using an Iterative-Closest-Point-Algorithm (ICP), (3) Marking digital registration points with holes within IOS-stl, (4) Transformation of the spatially aligned IOS-stl to LabelMap and storage in DICOM (IOS-DICOM), (5) Alignment of DICOM and IOS-DICOM, (6) Controlled positioning of digital reg. points and clinical correlation.
Fiducial localization error (0.48 mm) and Target registration error (0.65 mm) is comparable to those of tooth-supported registration methods.
This approach of marker-free registration for navigation-assisted-surgery could improve the treatment in edentulous patients avoiding additional imaging and invasive marker insertion.
