Categories: Implants

Zygomatic Implants

Did you walk into your dentist’s office hoping to replace your missing teeth, but were told you didn’t have enough bone for a conventional dental implant? Do not despair! Chances are we can still replace your teeth with zygomatic implants. Unlike traditional implants that are anchored on to your jawbones, zygomatic implants are placed into the stronger, sturdier zygoma bone (or the cheekbone), which lies right above your upper jaw.

First introduced by Dr. Per-Ingvar Branemark in 1988, zygomatic implants have been used in the profession for over two decades. With well-documented cases and predictable outcomes, these implants are viable alternatives to bone grafting.

A list of frequently encountered dental terminologies is presented below to help you through the article.

Glossary Of Frequently Used Dental Terminologies:

Dental Term	Meaning
Maxilla	The jaw or jawbone, specifically the upper jaw in most vertebrates. In humans it also forms part of the nose and eye socket.
Zygoma	A bone of the human skull commonly referred to as the cheekbone or malar bone
Dental Implant	The dental implant is a surgical component, shaped like the root of a natural tooth that is placed within the bone of the maxilla or mandible to support an artificial tooth like restoration.
Abutment	The dental implant abutment is that part of the fixture that connects the artificial crown to the underlying dental implant.
Anterior	Front or up ahead
Posterior	Behind
Prosthesis	An artificial replacement of a missing natural body part, which in our case is the tooth.
Provisional Restoration	The artificial restoration that is placed temporarily till healing completes or the final restoration is ready is called the provisional or temporary restoration.
Occlusion	Defined simply, occlusion is the science of contact of the surfaces of teeth in different situations, eg while biting, while chewing, while talking, swallowing, etc.
Atrophic bone	Severe reduction in bone structure, commonly seen in older individuals.
Immediate Loading	The process of placement of a prosthesis immediately after the implant surgery to assist in esthetics, function, rehabilitation and recovery.
Denture Conversion	The process of using a premade denture for immediate loading after the completion of surgery.

What are Zygomatic Implants?

Zygomatic implants are long implants (30–62.5 mm) that obtain their main anchorage from the zygoma bone in the presence or absence of maxillary alveolar bone. They are designed to allow for implant‐supported prosthesis placement where maxillary bone support is inadequate.

Why Zygomatic Implants?

The primary requirement for replacing missing teeth with a dental implant is the presence of adequate bone structure. However, in the absence of sufficient bone volume (atrophic bone), the dental team is presented with two options – bone grafting or graftless solutions.

While bone grafting comes with its own advantages, the treatment process if often lengthy and requires multiple surgical appointments. Also, bone grafting procedures are quite invasive, resulting in donor site morbidity in case an autograft (which is considered the gold standard) is used.

Zygomatic implants are a viable alternative for the rehabilitation of the atrophic posterior maxilla with both the classical two stage and immediate loading protocols. They avoid complex grafting and sinus lift procedures and therefore contribute to a shorter and more comfortable treatment.

Furthermore, zygomatic implants can be used in case of failed conventional implant placement, failed sinus augmentation or grafting procedures.

Benefits Of Zygomatic Implants:

Remarkable Success Rates:

Innumerable studies conducted on zygomatic implants over the decades demonstrate very high success rates. A systematic review published in the year 2014 by Goiato et al. evaluated the clinical studies conducted between 2000 and 2012 on the follow-up survival of zygomatic implants. The analysis showed a promising survival rate of 97.6%

Shorter Treatment Time:

The treatment time is considerably shortened with zygomatic implants as complex procedures like bone grafting and sinus lifts can be avoided. Also, these implants can be loaded immediately, thus resulting in an immediate rehabilitation of the missing tooth structure.

Reduced Treatment Cost:

Rehabilitation with zygomatic implants eliminates the need for high-priced bone augmentation procedures and multiple surgeries. Hence, they can be considered more pocket-friendly than the other alternatives.

Increased Patient Satisfaction:

In a multi-centre study conducted by Hirsch et al on the success rates of zygomatic implants, they observed that over 80% of the patients were extremely satisfied with the aesthetic and functional outcomes of the procedure. Also, for the patients who are highly anxious and skeptical to undergo multiple surgeries, these implants are a viable alternative.

Steps In The Procedure:

The phases in the procedure can be simply explained with the following flow chart

A prosthetically-driven approach always ensures the best results. Hence, the initial step involves a thorough evaluation of the patient’s clinical and medical condition. This will help the surgeon in establishing the correct ‘entry point’ for the implant placement.

Potential implant sites are determined with CBCT images (as shown in figure)

The surgical phase involves the following steps:

Surgical Phase:

Selection of optimum entry point in the alveolar crest based on the scanned images.

Flap reflection and placement of implants.

Verification of implant positions with a radiograph or volumetric image

Flap closure.

The surgical procedure can also be carried out with the use of 3D printed guided stents which assist in precise placement of implants according to the plan.

The prosthetic phase begins soon after surgery when a previously made denture is converted intra-orally into temporary implant prosthesis. This temporary denture will remain in place until the permanent prosthesis is fabricated.

Prosthetic Phase (Intermediate And Final):

Open tray impression with splinted impression copings

Jig verification of the implant positions

Jaw relation verification

Bridge design using CAD-CAM technology

Fabrication of all zirconia bridge or titanium framework for crown cementation

Trial and finishing

Final luting of crowns to Titanium framework (Malo bridge) and final fixation in the mouth.

In case of poor lip support, the clinician may even opt for an implant supported overdenture as the final prosthesis to obtain optimum facial contours and esthetics.

Conclusion:

Rehabilitation of atrophic maxilla with zygomatic implants is a predictable and cost‐effective treatment modality. The benefits of zygomatic implant reconstruction versus traditional implant reconstruction include shorter treatment time frames, avoidance of the need for bone grafting and its associated morbidity, fewer total implants required for a fixed prosthesis, and the fact that zygomatic implants allow the potential for immediate functioning.