Zygomatic implants in total upper edentulous patients

Edentulism should be considered a disease associated with important amounts of morbidity and health issues. Dental implant treatment is not always an option due to advanced bone resorption and/or maxillary sinuses pneumatisation that leads to insufficient amounts of bone for implants anchorage. In the past decades, bone grafting prior to dental implant placement has become a routine treatment in oral rehabilitation. Despite many publications, the success of sinus grafting procedures remains controversial. In a recent systematic review of the lateral window approach, the estimated annual failure rate is 3.5%, resulting in a 3-year implant survival rate of 90.1. In the past decades, zygoma implants (ZI) have proven to be an effective alternative to manage patients with atrophic edentulous maxilla, as well as for oncological defects. Initially the ZI was introduced to rehabilitate patients with extensive maxillary defects caused by tumor ablation, trauma and congenital defects. Nowadays, this technique has been successfully used to restore severe atrophic maxilla.

Key contraindications for zygomatic implants

Contraindications to the use of zygomatic implants include:

• Acute sinus infection
• Chronic infectious sinusitis
• Maxillary or zygoma pathology
• Underlying uncontrolled or malignant systemic disease
• The use of bisphosphonates
• Radiotherapy
• Heavy smoking (more than 20 cigarettes a day)

 Key indications for zygomatic implants

Ideally, any maxillary sinus pathologies should be treated before placing ZI. After a clinical examination, it is imperative to perform a special investigation (CT, CBCT) for an appropriate treatment planning. Computed tomography (CT) is critical to assess the sinus’s status and the surgical site. Moreover, this examination allows to estimate the amount of zygomatic bone and establish the trajectory, angulation and expected emergence of the ZI’s profile. Bedrossian et al. (2010) gave recommendations on when to position ZI implants based on residual maxillary bone. They divide the maxilla into three zones: zone 1, the premaxilla; zone 2, the premolar area; and zone 3, the molar area. Clinicians need to determine the availability of bone in all three zones. CT or CBCT can be used to determine the amount of bone in these zones as well as in the zygomatic arch, in both horizontal and vertical dimensions.

Summary of Bedrossian et al.’s guidance (table below):

• Adequate bone in zone 1 and bilateral lack of bone in zones 2 and 3 > Typically, two to four conventional straight implants are distributed in the anterior maxilla plus one zygomatic implant on each premolar/molar side.
• Adequate bone in zone 1 and lack of bone in zones 2 and 3 on only one side > One single zygomatic implant is placed and conventional implants are positioned in the anterior maxilla and on the side opposite the zygomatic implant.
• Inadequate bone in zone 1 and adequate pristine bone in zones 2 and 3 > An anterior zygomatic implant, together with posterior conventional implants are recommended.
• Lack of bone in all three zones of the maxilla > Four zygomatic implants can be used for rehabilitation.

Treatment recommendations

 ZI clinical case in presence of bone in zone I performed by Mr Andrea Tedesco

Interested in growing your knowledge of zygomatic implants? We are planning a 1-day course soon. Write us at info@theoralsurgeryacademy.com  if you want to know when the course date goes live. Meanwhile, check out our upcoming 1-day Oral Surgery courses for Dentists and Dental Hygienists and Therapists.