Computer-Guided Approach for Placement of Zygomatic Implants: Novel Protocol and Surgical Guide.

PURPOSE: This study introduces a novel protocol for the placement of zygomatic implants utilizing presurgical planning with 3-dimensional (3D) computed tomography (CT)/cone-beam (CB)CT diagnostic technologies and advanced 3D printing through the development of a specific surgical guide.

MATERIALS AND METHODS: The protocol relied on large field of view CT/CBCT for an accurate assessment of the maxillary arch to plan zygomatic implant receptor sites. CT/CBCT-derived surgical guides of a novel design were then fabricated using 3D printing technology. An exact replica of the entire maxilla and zygomatic bone was then fabricated in actual scale model size to allow for a simulation of the operation using replicas of implants to be used during the surgical intervention. Guidance was also provided for the sinus fenestration as part of the surgical template. Four patients received a total of 10 zygomatic implants all placed by the same surgeon.

RESULTS: Preoperative positions of the zygomatic implants were compared with the postoperative implant positions by merging the pre- and postoperative CT scan datasets. The degree of accuracy of the superimposition was measured utilizing sophisticated software. Apical, coronal, and angular deviations were determined for each implant. Deviations from the computerized project to the actual implant positions ranged from 2 mm to 3 mm with angular deviations ranging between 1.88 and 4.55 degrees.

CONCLUSIONS: Placement of zygomatic implants requires surgical experience due to close proximity of vital anatomical structures. This study used methods of superimposition that illustrated satisfactory correspondence between inserted implants and the virtual plan. No adjacent vital anatomical structures were damaged. The novel surgical guide design afforded the surgeon visual control of the drilling protocol. Positioning the guide in close proximity to the entry point of the zygomatic body aided control of the drills up to the vicinity of the exit point, significantly limiting problems associated with angular deviation. Reducing errors and complications is essential for zygomatic implants to remain a viable treatment alternative, and further research on a guided approach to their placement is encouraged.