Insertion of zygomatic implants using a CAD-CAM surgical-template.

OBJECTIVES: The aim of the study was evaluate the accuracy of the computer-guided zygomatic implants insertion in patients with seriuos atrophy of the upper maxillary and excessive pneumatisation of the maxillary sinus as alternative to sinus lift. METHODS: At the Department of Oral Sciences of “Sapienza” University of Rome were selected 2 patients, total edentulous in the posterior maxilla, in the period between April 2009 and June 2009.The implant treatment was planned by using the SimPlant® software to virtually design zygomatic implant placement on CT DICOM images. The maximum of implant's length to reach the the zygomatic process of the maxillary was 34 mm, the least length was 30 mm. The zygomatic implants were inserted ambulatory , with local anaesthesia, using a SAFE SYSTEM® surgical-template, mucosa-supported ,realized by stereolitography, which allowed us to use a minimally invasive surgical technique(flapless).For each case treated has been evaluated the deviations between the planned and the placed implants by using Mimics® , which is a software that allows to pairs-wise align the pre-operative 3D representations of the jaws (maxilla + zygomatic planned implants) with their counterparts in the post-operative images. Typically an iterative closest point (ICP) algorithm is used to match the jaws. RESULTS: The maximum angular deviation, calculated as 3D angle between the longitudinal axis of the planned and placed implant, was 9,8 degrees; the maximum global deviation, defined as the 3D distance between the apical centres of the corresponding planned and placed implants was 2,8 mm. CONCLUSION: Zygomatic implant insertion using a computer-guided technique is an alternative to sinus lift, but in order to avoid significant angular deviations it is necessary to have high definition CT images and control the fitting of the surgical-guide on the mucosa.