What Are Zygomatic Implants?
Zygomatic implants can be defined as implants anchored into the zygoma or the cheekbone rather than in the maxilla or upper jaw. In the current scenario of dental implantation, zygomatic implants are usually considered for placement using an immediate loading protocol.
What Are the Indications for Zygomatic Implants?
The main indication for the dentist to opt for zygomatic implants are as follows:
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Severely resorbed edentulous maxilla (loss of teeth in the upper jaw).
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In partially edentulous patients, as an alternative to sinus augmentation procedures.
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When it is to be used as a consequence of failed sinus augmentation for other implant procedures.
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For jaw and dental rehabilitation after resection of jaw cancers, tumors, or trauma.
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When there is a failure of conventional implants.
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Failure of bone grafts placed due to multifactorial or systemic factors in the patient.
The reason for the dental surgeon to use zygomatic implants is always when there is no viable alternative for the patient's rehabilitation of jaw functions, speech, and masticatory functions. In edentulous patients, the biggest clinical challenge is to accommodate bone regeneration modalities to compensate for the continuous resorption of the maxillary alveolar process that keeps occurring post a tooth loss or tooth extraction.
Zygomatic implants can be planned in conjecture with several strategies proposed in recent decades in the field of implantology. For example, clinically challenging surgical methodologies can be adopted to rehabilitate the edentulous patient or in patients indicated for zygomatic implants such as bone regeneration before the placement of conventional implants, Lefort 1 osteotomy procedures with repositioning of the maxillary segment (either downward or forward positions), distraction osteogenesis, inlay grafting procedures either to the maxillary antrum or to the nasal floor, onlay grafting procedures or interpositional bone grafting etc.
What Are the Recent Developments in Zygomatic Implants?
The introduction of zygomatic implants was originally the revered father of modern implantology, Professor Branemark. Since then, several authors and researchers have been in defense of this methodology to compensate for the continuous atrophy or bond resorption that takes place in the maxilla or upper region with zygomatic implantation.
Zygomatic implants also offer an additional advantage to the dental surgeon or the implantologist by the possibility of loading the implant immediately (immediate implant loading). When techniques like Lefort 1 maxillary advancement are used, then virtual surgical planning is of great benefit to the operator.
Specific imaging communications in dentistry have emerged like DICOM (digital imaging and communications in medicine) management software that is used for 3D (three-dimensional) planning and reconstruction prior to the zygomatic implantation procedure. The softwares that support this purpose is Simplant O and O version, Dentsply, Leuven, etc. Through this 3D planning, the proper emergence profile of the implant can be planned by the operator and also ensure adequate alveolar bone support all around the implant to prevent implant failure. Additionally, these softwares offer the advantage of selecting surgical or provisional prosthesis post-implantation based on the extent of maxillary advancement planned by the surgeon, like occlusal splints, fixation of mini plates, etc.
What Is the Procedure for Placement of Zygomatic Implants?
The implant surgery can be performed under general anesthesia preferably. A crestal incision can be given bilaterally on the maxilla. Post the elevation of the mucoperiosteal flap to the level of the zygomatic buttress and palatal segments, Lefort 1 osteotomy procedure can be performed. The maxilla is then osteotomized (using an osteotome instrument in rotational motion) and can be consequently repositioned or fixed with screws to the bone to increase stability.
As suggested by revered Branemark, the original procedure includes the insertion of these zygomatic implants through an intrasinusal trajectory with the help of a long anchored implant ranging from 35 to 55 mm. However, because of the palatal emergence profile of these zygomatic implants, it becomes difficult to prosthetically rehabilitate the patient for the clinician, and the patient may have compromised cleaning in that area leading to poor oral hygiene and peri-implantitis or peri-implant mucositis conditions (that may lead to long-term implant failure).
In the present scenario in dental implantology, the advocated methods vary from practitioner to practitioner; however, most authors or clinicians support the placement of zygomatic implants with certain modifications technically, as mentioned earlier, with multiple methods like the use of onlay bone grafting, bone regeneration, and Lefort 1 maxillary advancement procedures.
What Are the Challenges in the Placement of Zygomatic Implants?
In the case of zygomatic implants, the clinically challenging surgical method is to achieve a proper emergence profile of the implant platform. Hence, computer-assisted planning on a virtual platform or through the above-mentioned 3D software along with prefabricated surgical splints can ensure that the emergence profile is as per operator and patient expectations and simultaneously corresponds to correct maxillary advancement repositioning for long term stability of the implant.
Another major challenge is the severely atrophied maxillary region or alveolar process that requires a 3D approach. A well-designed prosthesis by the surgeon can overcome the complications associated with anterior maxillary defects, saggital atrophy, and in the case of less labial support. Vertical defects need to be managed by hybrid prosthesis, metal-ceramic or zirconia bridging, or prosthetics to restore the conventional pink and white esthetics associated with normal gingival and tooth structure and form. As zygomatic implants already have the advantage of being immediately loaded, the achievement of the dental implantologist or surgeon of bone anchorage and primary implant stability by precise planning virtually and immediate provisional prosthesis fabrication can help considerably shorten the time period of having the jaw functions and form restored in the edentulous patient.
Conclusion
To conclude, zygomatic implants are of great use in patients with the atrophic edentulous maxilla. It is a viable alternative for those patients seeking sinus augmentation procedures, and due to recent advances in virtual planning and advanced surgical methods that accompany implantation, long-term success can be ensured by the dental implantologist.
