These involve the pterygoid and the zygomatic implants. Both have been documented as an alternative for the rehabilitation of the atrophic posterior maxilla with both the classical two stage and immediate loading protocols. They avoid grafting and sinus lift procedures and therefore contribute to a shorter and more comfortable treatment.
Further indications for extra maxillary implants include failed conventional implant placement, failed sinus augmentation or grafting procedures, rehabilitation after tumor and trauma resections.
Zygomatic Implants
In the atrophic posterior maxilla, in general one zygomatic implant is placed on each side of the maxilla, in combination with 2-4 conventional implants in the anterior region. For the totally resorbed maxilla, when placement of anterior implants is not possible the concept can be expanded by inserting 2 additional zygomatic implants in a more anterior position (Quad zygoma). Zygomatic implants nowadays are usually immediately loaded with a fixed bridge.
Prognosis:
Long-term prospective studies with the classical 2-stage and immediate loading approaches document high success rates with only minimal complications. The cumulative survival rate of zygoma implants is 96% after 12 years.
Possible complications:
The most common complication associated with zygomatic implants is sinusitis. Appropriate pre-surgical diagnostics and evaluation of the sinus as well as using the extra-sinus surgical approach and immediate loading of the implants seem to reduce or even eliminate this complication. Other complications reported during and after the insertion of zygoma implants include infraorbital nerve paresthesia, orosinusal fistula and perforation of the orbit.
