In situ repair of a fractured zygomatic implant

Zygomatic implants (ZIs) offer a robust solution for maxillary rehabilitation in patients with severe atrophy, oncological resection, or following trauma, where the use of conventional implants is not practical. However, because of their length, design, and placement, ZIs face mechanical challenges which can lead to complications such as fracture. This treatment details the novel, minimally invasive in situ repair of the fractured shaft of a ZI. The patient, diagnosed with carcinoma of the right maxillary sinus, was treated with hemimaxillectomy and conventional radiotherapy. She was restored with 3 ZIs supporting a prosthesis which also obturated some small oroantral fistula. After 11 years, the front left ZI fractured. Removal of the retained portion of the implant would have been highly destructive and was impractical because of its close relationship with the orbital rim. Instead, a custom-made coupling device was created through computer-aided design and computer-aided manufacturing (CAD-CAM) technology to attach to the threaded remnant and return the implant to function. Preparation involved removing bone from around the remnant, cleaning the exposed threads with custom-designed instrumentation, and attaching the coupling. An abutment was fitted, and a replacement milled bar and obturator prosthesis were provided. This repair circumvented the need for invasive surgery and enabled a swift return to function, highlighting the need for adaptability and creativity when managing complex problems with ZIs, as well as the utility of engineering principles and use of CAD-CAM technology in implant dentistry.