Dental Implants Information

Basal Zygomatic Implants

Zygomatic implants are an evidence-based surgical and prosthetic solution for both two-stage and immediate loading protocols
Today, zygomatic implants are usually placed using an immediate loading protocol
The main indication for zygomatic implants is the severely resorbed edentulous maxilla, but they can also be used in partially edentulous situations
Indications for zygomatic implant insertion include: alternative for sinus augmentation, failed sinus augmentation, rehabilitation after tumor resection or trauma, failure of conventional implants, failure of previous bone grafts
The placement of zygomatic implants requires adequate training and surgical experience

Indications

  • When there is insufficient bone in the upper jaw
  • When conventional implants have failed
  • Failed sinus lift and bone grafting procedures
  • To avoid bone grafting procedures and their associated complications
  • In patients who desires fixed set of teeth
  • Can be used in completely edentulous or partially edentulous patients
  • In maxillary resection cases due to tumour
  • In acquired or congenital defects
  • In syndromic patients

 

Fig 1: Zygomatic implants are inserted through the alveolar crest and maxillary sinus involving the zygomatic bone for anchorage.

Clinical recommendations

In the classical protocol, zygomatic implants are inserted through the alveolar crest and maxillary sinus involving the zygomatic bone for anchorage (Fig 1). For visualization of the correct implant position access to the maxillary sinus is necessary. Access preparation to the maxillary sinus is performed at a lateral posterior aspect at the later implant position and the Schneiderian membrane is elevated in an anterior direction. The implant is placed subsequently and is located at the inner aspect of the sinus wall, often without membrane perforation (Fig 2).

Alternatively the extrasinus placement approach has been described in order to reduce incidence of sinus complications and to improve the implant location and position of the emergence profile more crestally.

Due to the long drilling distance to the zygomatic bone and in order to protect critical adjacent anatomical structures, placement of zygomatic implants requires considerable surgical training and experience and meticulous diagnostic planning. To receive an adequate overview over the anatomical structures, presurgical 3D planning with CT or CBCT scans is a must.

The drill protocol is applied in order to achieve an implant insertion torque between 35-45 Ncm in all bone densities for optimal primary stability in immediate function protocols. Use of optional drill steps such as the twist step drills are recommended in case the insertion torque is surpassing 45 Ncm.

Caution: Never exceed an insertion torque of 45 Ncm. Overtightening may lead to damaging of the implant and fracture or necrosis of the bone.

Fig 2: The implant is placed subsequently and is located at the inner aspect of the sinus wall, often without membrane perforation.

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.

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.