Implant-prosthetic therapy for the replacement of one or more teeth is an effective and increasingly widespread practice. However, in the case of edentulous maxillary atrophy or in conditions that cause a volume/quality reduction of the bone, it is not possible to choose a traditional implant treatment.
Over the past 30 years, the ideal strategy for the treatment of patients suffering from these conditions has included bone regeneration by dental bone grafting, an invasive procedure that requires several surgical procedures and necessitates quite long healing times.
The zygomatic implant is a valid alternative to bone grafting: it consists of an implant which has been anchored inside the zygomatic bone and whose pyramid anatomy lends itself to support functions.
Diagnostic investigations: how to plan the intervention
Before proceeding with the placement of the zygomatic implants, the patient must undergo examinations that allow the health-care professional to acquire useful information for planning the therapy and correctly identify the site where insert the implants. In addition to the assessments accomplished during the outpatient visit, it is usually performed a panoramic radiograph. The radiograph provides information on the anatomy of the patient’s skull, and in particular on the parts that will be involved in the insertion of the implant.
However, the most critical investigation in this phase is the computerized tomography (CT). This exam provides two-dimensional and three-dimensional images from which is possible to understand the jaw’s health, but also the density, volume and length of the zygomatic bone. Moreover, thanks to these investigations, it is possible to exclude sinusitis, polyps, or other pathological conditions that should be treated before proceeding with implant therapy.
Insertion of the zygomatic implant
Zygomatic implants are made of titanium self-tapping screws whose threaded surface are rough and oxidized. The length of the zygomatic implants is variable, but it is higher than that of traditional implants. The placement of the implant is performed through a surgical technique which requires considerable professional experience. Once placed, the implant ‘s long screw is extended from the palatal side of the alveolar region (i.e. the jaw bone area that supports the dental arch) to the body of the zygomatic bone, passing through the maxillary sinuses. Until a few years ago, the positioning of the zygomatic implants was performed using a standard technique, the same for all patients, whereas today, a personalized approach is preferred.
The intervention for the positioning of the zygomatic implant is usually performed under general anaesthesia, but recently the possibility of resorting to local anaesthesia associated with orally or intravenously administered sedation has been introduced.
Contraindications to the use of zygomatic implants
Some conditions are contraindicated for the use of zygomatic implants, including:
• acute sinus infection;
• any pathologies of the cheekbone or jaw;
• presence of any malignant or uncontrolled systemic pathologies.
Other conditions do not categorically exclude the use of zygomatic implants but could increase the risk of complications. These conditions are:
• chronic infectious sinusitis;
• intaking of bisphosphonates;
• smoking more than 20 cigarettes a day.
Also, patients diagnosed with rhinosinusitis before the intervention should be first treated by an otolaryngologist.
Zygomatic implants: possible complications
Some of the complications that have been reported following the use of zygomatic implants include postoperative sinusitis, hematoma or periorbital or subconjunctival oedema, lip laceration, pain, facial oedema, temporary paraesthesia, epistaxis, gum inflammation and orbital bone damage. Furthermore, in the first periods after the operation, difficulties in articulating the language and in performing oral hygiene practices could arise due to the encumbrance caused by the implant at the palate level.
However, in the treatment of patients with a reduction in the quality and volume of the supporting bone, implant therapy using zygomatic implants is less invasive and complicated than bone regeneration by grafting, i.e. the technique traditionally used in these cases. Furthermore, it appears that the zygomatic implants show better clinical results than the bone grafting technique and that they have a survival rate of over 90%. The efficacy, the low incidence of complications and the possibility of immediate loading make zygomatic implants a valid and safe alternative for the treatment of patients, such as those affected by atrophy advanced edentulous maxilla, who can’t rely on traditional prosthetic implant therapy,
· 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