Implant-prosthetic therapy for the replacement of one or more missing teeth is an effective and increasingly widespread practice, but there are conditions in which it is not possible to resort to traditional implant treatment. Usually, this limitation is due to the presence of problems such as edentulous maxillary atrophy and other conditions that cause a reduction in the volume and quality of the supporting bone. Over the past 30 years, the preferred strategy for treating patients with these conditions has involved bone regeneration by means of dental bone grafting. However, this technique is an invasive procedure that requires several surgeries and has a rather long healing time. The zygomatic implant is a therapeutic alternative to bone grafting: it is an implant that is anchored inside the zygomatic bone, whose pyramid-shaped anatomy lends itself to performing support functions.
Diagnostic investigations: how the intervention is planned
Before proceeding with the placement of the zygomatic implants, the patient must undergo a series of investigations which allow the Professional to acquire useful information to better plan the therapy and correctly identify the site or sites in which to insert the implants. In addition to the assessments that can be made during the outpatient visit, it is advisable to perform panoramic radiographs which provide information on the anatomy of the patient’s skull, and in particular on the parts that will be involved in inserting the implant. However, the most important investigation that is performed in this phase is computed tomography (CT), which provides both two-dimensional and three-dimensional images from which it is possible to deduce not only the state of health of the sinuses and jaw, but also the density, volume and length of the zygomatic bone. Thanks to these in-depth investigations, it is possible to exclude the presence of sinusitis, polyps, or other pathological conditions that should be adequately treated before proceeding with implant therapy.
Insertion of the zygomatic implant
Zygomatic implants consist of self-tapping titanium screws whose threaded surface is rough and oxidized. The length of zygomatic implants varies, but is generally longer than that of traditional implants. The placement of the zygomatic implant is performed thanks to a surgical technique that requires considerable experience on the part of the Professional. Once placed, the long screw that makes up the implant extends from the palatal side of the alveolar region, i.e. the area of the maxillary bone that supports the dental arch on which the teeth are normally placed, up to the body of the zygomatic bone, passing through the maxillary sinuses. Until a few years ago, the placement of zygomatic implants was performed according to a standard technique, the same for all patients, while today a more personalized approach is preferred.
The surgery for the positioning of the zygomatic implants is usually performed under general anesthesia, but recently the possibility of resorting to local anesthesia associated with sedation which is administered orally or intravenously has also been introduced.
Contraindications to the use of zygomatic implants
There are certain conditions that make it impossible to use zygomatic implants, including:
- acute sinus infection;
- any pathologies of the cheekbone or jaw;
- presence of any malignant or uncontrolled systemic pathologies, which prevent the patient from undergoing implant surgery.
Other conditions do not categorically exclude the use of zygomatic implants, but could increase the risk of complications. These conditions are:
- chronic infectious sinusitis;
- taking bisphosphonates;
- smoke more than 20 cigarettes a day.
Furthermore, patients who are found to be suffering from rhinosinusitis during the diagnostic checks performed before surgery should be treated by an otolaryngologist before being able to resort to implant therapy.
Zygomatic implants: possible complications
Some of the complications that have been reported following the use of zygomatic implants include postoperative sinusitis, periorbital or subconjunctival hematoma or edema, lip laceration, pain, facial oedema, temporary paraesthesia, epistaxis, gingival inflammation, and damage to the orbital bone . Furthermore, in the first periods following the operation, there may be difficulties in articulating language and in carrying out oral hygiene practices, due to the encumbrance caused by the implant at the level of the palate.
In any case, in the treatment of patients with a reduction in the quality and volume of the supporting bone, implant therapy with the use of zygomatic implants appears to be less invasive and complicated than bone regeneration by grafting, i.e. the technique traditionally used in these cases. It also appears that zygomatic implants show better clinical results than the bone grafting technique, and that they have a survival rate of more than 90%. The efficacy, the low incidence of complications and the possibility of immediate loading mean that zygomatic implants represent a valid and safe alternative for the treatment of patients in which it is not possible to use traditional implant-prosthetic therapy, such as cases of advanced edentulous maxillary atrophy.
Sources:
- Aparicio C. et al, Zygomatic implants: indications, techniques and outcomes, and the zygomatic success code. Periodontol 2000. 2014; 66(1):41-58
- Chrcanovic B.R. et al, Zygomatic implants: a critical review of the surgical techniques. OralMaxillofacSurg. 2013; 17(1):1-9
- Prithviraj D.R. et al, From maxilla to zygoma: A review on zygomatic implants. Journal of DentalImplants 2014; 4(1):44-47
- Wu Y. et al, Real-Time Navigation in Zygomatic Implant Placement: Workflow. OralMaxillofacSurgClin North Am. 2019