Restoring the Edentulous Severely Resorbed Maxilla
Zygomatic implants offer an alternative to bone grafting and sinus augmentation
Riad Almasri, DDS
To treat the edentulous maxilla, multiple options are available. A patient who elects to have a nonremovable, fixed dental prosthesis must have good quality and quantity of bone in order to be able to receive conventional dental implants, which have demonstrated a great amount of success over the years.1 Dental implants can improve quality of life for patients by facilitating the attachment of a highly functional prosthesis with excellent esthetics.2 When the immediate load concept is included, it can lead to increased acceptance rates. For the past few decades, the severely resorbed edentulous maxilla has presented a challenge. As an alternative to bone grafting and sinus augmentation, zygomatic implants have shown great success rates.3 These implants, which have high primary stability, enable immediate loading with fixed restorations,4 avoiding the average 9-month wait and multiple surgeries associated with grafting.5
A 57-year-old female patient presented to the practice seeking a fixed solution to replace an existing maxillary removable partial denture. After a comprehensive oral examination and review of her cone-beam computed tomography (CBCT) scan, a diagnosis of partially edentulous atrophic maxilla and mandible was made. The patient was presented with treatment options, both with and without grafting, for fixed, full-arch restorations.
She decided to proceed with the graftless approach, which would include the placement of two sets of bilateral zygomatic implants. Although the patient also received four mandibular implants to retain a complete set of fixed dentures, this article focuses on the treatment of the maxillary arch.
Using the CBCT scan, the maxillary sinuses were evaluated for any signs of inflammation or pathosis. The preprosthetic diagnostic evaluation included an assessment of esthetics, phonetics, lip position, and orofacial contours (Figure 1 and Figure 2). Maxillary and mandibular immediate dentures were fabricated, and to aid in implant placement, complete dentures were duplicated in clear acrylic for the guide.
Profound anesthesia was achieved using a combination of intravenous sedation, local infiltrations, and blocks. Crestal, sulcular, and posterior vertical incisions were made to permit the reflection of full-thickness flaps, which facilitated excellent visualization of the anatomy. A small, bilateral window opening in the sinus was made to better visualize the positioning of the implants' apices. The window's location was between the infraorbital foramen and the frontal notch of the zygomatic bone (Figure 3). A surgical guide was used to verify the amount of reduction needed, if any, as well as the position and alignment of the angle correcting abutments.
The zygomatic implants (Neodent® Zygoma GM™ Implant, Neodent) were planned prior to surgery using a CBCT scan and then positioned using an intrasinus approach (ie, placement of the implant within the boundaries of the maxillary sinus) at the sites of teeth Nos. 4, 6, 11, and 13. Next, the prosthetic abutments (GM™ Mini Conical Abutment, Neodent) were placed using the surgical guide. These abutments were selected to idealize the height and angle of prosthetic emergence.
Upon achieving primary closure (Figure 4), the prefabricated immediate dentures were fitted in, using the palate as a guide for the maxilla and a premade vinyl polysiloxane (VPS) occlusal record to orient the mandible against the maxilla at the proper vertical dimension of occlusion. Afterconverting the immediate dentures into interim fixed dental prostheses in the lab, they were seated and secured to the implants. The occlusion was verified and adjusted, and polytetrafluoroethylene tape and a temporary restorative material (Cavit™, 3M) were used to block the screw access holes (Figures 5 and Figure 6). After a postoperative CBCT scan was acquired (Figure 7), the patient was dismissed with postoperative instructions. Follow-up appointments were scheduled for 1, 3, 8, and 16 weeks postoperatively (Figure 8 and Figure 9). After a total of 6 months of healing, the patient will be presented with options for the definitive prosthesis.
When treating the edentulous severely resorbed maxilla, clinicians face both surgical and prosthetic challenges. The prostheticchallenges involved have lessened due to the availability of angle correction abutments and techniques to place zygomatic implants in an extrasinus position. However, research shows that an intrasinus technique is preferred when lateral forces are invovled.6 One of the greatest advantages of the screw-retained prosthesis is the elimination of the cement, which has been associated with implant failure.7 Research indicates that when presented with options, many patients will choose immediately loaded zygomatic implants over traditional treatment with bone grafts.8
About the Author
RIAD ALMASRI, DDS
Academy of Osseointegration
International Congress of Oral Implantologists
Nova Southeastern University
College of Dental Medicine
Fort Lauderdale, Florida
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