Success Criteria in Zygomatic Implant Dentistry

Abstract

The extreme maxillary atrophy that indicates the use of zygomatic implants (ZI) is associated with resorptive changes in both alveolar and basal bone, and prevents direct placement of conventional endosseous implants. Therefore, using conventional criteria to describe implant success/failure is not sensible for ZI. Moreover, protocols for the rehabilitation of the atrophic maxilla using ZI have been continuously evolving to overcome initial shortcomings of early initial shortcomings of early techniques. The current zygomatic approach is relatively new, especially if the head of the ZI is located in an extra-maxillary buccal position to the alveolar crest with no alveolar bone around its perimeter. The zygomatic-related rehabilitation protocol differs from conventional implant therapy with respect to biomechanics, clinical procedures, outcomes, and eventual complications such as soft tissue incompetence or recession that may lead to recurrent sinus/soft tissue infections and aesthetic patient complaints. Currently, the way in which results and complications of ZI are reported in the scientific literature is inconsistent and lacks a standardized approach. Specific criteria to describe success/survival of ZI, including a standardized way to report on rhinosinus pathology associated with ZI, is necessary. The aim of this chapter is to critically review success criteria used for conventional and zygomatic implants. Finally, a revisited Zygomatic Success Code describing specific criteria to score the outcome of a rehabilitation anchored on ZI is proposed. The authors use the ORIS acronym to name four specific criteria to systematically describe the outcome of ZI rehabilitation: Offset: evaluation of prosthetic success based on the final positioning of the zygomatic implant with respect to the middle of the alveolar crest in the horizontal dimension. Rhinosinus status report: a pre, and postsurgical cone-beam computed tomography comparative approach to evaluating whether sinuses are healthy; a clinical questionnaire where “yes” and “no” answers can be given. Infection permanence related to dehiscence: an evaluation of soft tissue signs of infection or dehiscence on a grading scale based on reference photographs. Stability report: accepting as success some mobility until dis-osseointegration signs of rotation or apical pain present.