Immediate Implant-Supported Auricular Prosthesis Using Surgical Navigation and CAD/CAM Technology – an In Vitro Trial

Abstract

Purpose: To investigate the feasibility of provision of immediate implant-supported auricular prosthesis using surgical navigation and CAD/CAM technology. Methods & Materials: A stereomodel was generated by rapid-prototyping (RP) based on the CT Digital Imaging and Communications in Medicine (DICOM) data set of a patient with a defective right auricle. By using the RP software, a mirrored image of the contralateral intact ear was produced and used for implant planning. The thickness of overlying soft tissues at the defect side was also measured by the software. The surgical field was then defined and a disc of 120 mm in diameter, centred at the external acoustic meatus, was segmented out from the stereomodel according to the data measured to simulate the mastoid bone. The defect was filled with a translucent silicone material to simulate the skin. A silicone mould of the mirrored ear was fabricated by RP. A wax pattern was produced from the mould and the silicone ear was processed with a housing made of acrylic resin. During operation, a silicone flap was raised and two dummy implants were inserted as planned using the surgical navigation system. The flap was thinned and closed. After the post-operative CT was taken, appropriate abutments were selected and inserted into the implants. Magnets were placed on the abutments and picked up by the acrylic housing inside the silicone ear with cold-cured acrylic resin. The data of the post-operative CT were compared with the planned trajectories by image fusion technique using surgical navigation software. Drill depth, angle in axial and coronal plane, and entry point position of each implant were measured. Results: The mean deviation of the post-operative data from the planned ones were as follows: drill depth (0.7mm), angle in coronal plane (1.6°), angle in axial plane (1.5°) and entry point position (2.6mm). The whole process including preoperative planning, software manipulation, operation by navigation, fabrication and insertion of auricular prosthesis appeared to be feasible and acceptable for clinical application. Conclusion: Immediate implant-supported auricular prosthesis using surgical navigation and CAD/CAM technology seems to be feasible for clinical application.