Guided implant surgery on oral cancer patients: in vitro study.

PURPOSE: Many oral cancer patients (OCPs) are unable to wear conventional prostheses due to the disease and treatment effects, so they are candidates for oral rehabilitation with osseointegrated implants. A guide suitable for OCPs was designed and tested.
METHODS: Image-guided systems based on a custom template for oral implant placement are now widespread among healthy patients, but this has not been extended to OCPs. The EasyGuideT system (Keystone Dental, Burlington, MA, USA) for template stabilization is used on healthy edentulous patients, achieved by bone screws, mini-implants or stereolithography with a bone support. All these systems are invasive and cannot be used in many oral cancer patients. We adapted the EasyGuideT to OCP rehabilitation. The first stage focused on developing a template-positioning system for use on edentulous mandibles that is non-invasive, repeatable, stable on the oral mucosa, consistent with the operating room asepsis, and comfortable for the patient. This repositioning system consists of a cube fiducial marker and an extra-oral support using a facial thermoplastic mask. The mask is linked to the surgical template through the cube. The second stage consisted of direct evaluation of the repositioning system reproducibility, performed on 5 adult cadaver skulls.
RESULTS: The translation errors and rotation errors obtained using the modified EasyGuideT system were satisfactory in ex vivo experiments on cadaver skulls.
CONCLUSION: A non-invasive repositioning system for image-guided implant surgery on oral cancer patients is clinically feasible using a cube fiducial marker and extra-oral support with a facial thermoplastic mask.