The Zygoma Anatomy-Guided Approach: ZAGA—A Patient-Specific Therapy Concept for the Rehabilitation of the Atrophic Maxilla
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Zygomatic implants are used for prosthetic rehabilitation of the severely atrophic maxilla. The original surgical technique (OST) at modum Brånemark prescribed an intra-sinus pathway of the implant from a palatal site entrance and preparation of an antrostomy for visualization during implant insertion. However, different morphologies of the edentulous maxilla exist. The more concave the maxillary anterior wall, the more palatal position the implant head position will be. If the maxilla is severely atrophic, the palatal entrance will occur through thin cortical bone. These situations frequently result in bulky prosthetic constructions, impaired hygiene and, eventually, sinus complications.
To overcome the limitation of OST and to facilitate ongoing use of zygomatic implants, different surgical approaches, including the extra-sinus technique, have been described. The author has previously introduced a novel protocol, named Zygoma Anatomy-Guided Approach (ZAGA) which aims to promote a patient-specific therapy. In most cases, this method avoids the opening of a window or slot into the lateral wall of the maxillary sinus prior to implant placement. Instead, a muco-periosteal flap, including the posterior maxillary wall and the superior zygomatic rim, is raised, to allow visualization of the complete surgical field. The surgical management of the implant site is guided by the anatomy of the patient and the conservation of eventual remaining alveolar bone is critical.
A classification describing the variations of the zygomatic buttress anatomy helps the surgeon to choose the coronal and apical entrance points for the zygomatic drill. A rationale is proposed to choose the osteotomy position and characteristics, which usually leads to perforating the anterior Zygoma cortex twice. As a consequence, the path of the implant may vary from completely intra-sinus to completely extra-sinus. Using specific success criteria for zygomatic implants, the ZAGA method has yielded significantly improved results along with a reduced number of long-term complications compared to previous techniques.
In addition to the clinical aspects, we present a concept: Zygoma ZAGA Centers network, aiming to disseminate the ZAGA principles and methodology among professionals and patients for safe and predictable zygoma-related rehabilitation.
KeywordsZAGA Extra-sinus Extra-maxillary Zygomatic implants Immediate loading Zygomatic success criteria Patient-specific therapy Atrophic maxilla Zygoma ZAGA Centers
The ZAGA protocol arises from the desire to overcome the drawbacks of the original technique. Like almost all innovations, the one described in this chapter would not have happened without an origin from which to evolve. In this regard, I wish to deeply thank my teacher and mentor Prof. P-I Brånemark for sharing his vision of the use of zygoma bone for remote implant anchorage. I am also grateful for the opportunity he gave me to publish the first report in 1993 showing the utility of zygomatic implants in maxillary rehabilitation. In addition, I would like to recognize the generosity and support of Prof. Dr. Chantal Malevez during my first three surgeries. I still smile when remembering those first intense moments. I would like to acknowledge Mr Graham Blackbeard, CEO of SouthernImplants Cº, for the intense discussions we have had to achieve the best possible zygomatic implant design. SouthernImplants is the manufacturer Cº of “Zygan”, the Zygomatic model of implant used to illustrate this chapter. Finally, I would like to acknowledge all the colleagues who have generously shared their experiences in the field of zygomatic implants through publications. Without them, I could not be presenting this work.
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