Introduction

The following case report presents the treatment of a patient who has undergone multiple failed attempts at reconstructing her maxillary arch with dental implants. Using the Bedrossian systematic treatment planning protocol, the patient was found to have non-restorable remaining maxillary teeth, a composite defect and available alveolar bone in Zone 1, and missing bone in Zones 2 and 3 bilaterally. Therefore, the protocol for the zygoma concept with immediate loading with a fixed provisional hybrid prosthesis was followed. For anterior support, two axial BLX^® implants (Straumann, Switzerland) were placed in the premaxilla and, for posterior support, one zygoma implant (Straumann^® Zygomatic Implants ZAGA, Switzerland) was placed in each side of the posterior maxilla.

Initial situation

A 58-year-old female presented with failing maxillary dentition as well as several unsuccessful attempted reconstructions of her posterior maxilla with dental implants (Fig. 1, Fig. 2). She was seeking treatment options for the reconstruction of her maxilla with a fixed prosthesis. She had no pertinent medical conditions and no known drug allergies.
She had significant resorption of her posterior maxillary alveolar ridges (Fig. 2) as well as failing periodontally involved anterior maxillary teeth with 3+ mobility of each tooth (Fig. 3).

Treatment planning

The surgical treatment involved the removal of the remaining maxillary teeth and the placement of two axial, BLX® implants (Straumann, Switzerland) for anterior support, as well as the placement of one zygoma implant (Straumann® Zygomatic Implant ZAGA™, Switzerland) in each side of the posterior maxilla for posterior support. Once an insertion torque of 40 Ncm is reached, the use of screw-retained abutments and temporary titanium cylinders allow the “direct conversion” of the patient's pre-operatively fabricated full maxillary denture to a fixed implant-supported hybrid provisional.

Surgical procedure

The patient was pre-medicated with 2 grams of amoxicillin one hour prior to the treatment. The operation was conducted under intravenous sedation and local anesthesia. A full-thickness mucoperiosteal flap was elevated, and the remaining premaxillary teeth were removed (Fig. 4). A 4 mm alveoloplasty allowed the creation of a consistent topography between the posterior and anterior maxilla. Two, 10 mm long, 4.5 mm BLX® implants were placed in the lateral incisor position with 40 Ncm of insertion torque (Figs. 5, 6). Intraoperative evaluation of the lateral maxillary wall contour was consistent with a ZAGA 1 form on the right and ZAGA 4 on the left. A 35 mm round Straumann® Zygomatic Implant was placed in the right posterior maxilla (Fig. 7) and a 35 mm flat Straumann® Zygomatic Implant in the left posterior maxilla (Fig. 8).

Prosthetic procedure

Zygoma screw-retained abutments on the zygoma implants (Figs. 9a, 9b), as well as screw-retained abutments on the anterior BLX® implant, along with temporary titanium cylinders allowed the “direct”, intraoral conversion (Figs. 10a,10b,11) of the patient's prefabricated full maxillary denture to an immediate-load fixed hybrid provisional (Fig. 12).

The OPG and CBCT confirmed the adequate placement of the two zygomatic implants (Figs. 13-15).

The final hybrid fixed prosthesis will be fabricated upon confirmation of osseointegration, 6 months after the surgical procedure.
The patient was instructed to continue the antibiotics for 1 week following the surgical procedure and to maintain a soft diet for the 6 months of the osseointegration period. Since the preservation of cross-arch stability is of the utmost importance, the patient was advised to report any sensation suggesting that the prosthesis might be mobile.

Treatment outcomes

The patient was seen on follow-up appointments and had no complaints. She was very happy with the esthetic and speech outcomes.

Fig. 16 gives a visual overview of this successful treatment, depicting the final position of Round and Flat Straumann® Zygomatic Implants, ZAGA™, on the right and left side, respectively, as well as the radiographic situation before and after implantation.