A New Approach to the All-on-Four Treatment Concept Using Narrow Platform NobelActive Implants
Although a number of approaches to implant-supported restoration of severely atrophic maxillae and mandibles have been developed, most of these treatments are costly and protracted. An exception is the All-on-Four concept, which uses only 4 implants to support an acrylic, screw-retained provisional prosthesis delivered on the day of implant placement, followed by a definitive prosthesis approximately 4 months later. After the introduction of a new implant design in 2008, a new protocol was developed for provisionally treating patients with severely atrophic jaws using the All-on-Four concept and 3.5-mm-diameter implants. This article describes that protocol and reports on the results of 227 implants after 1 to 3 years of follow-up. The cumulative survival rate was 98.7% at the end of 3 years, with a 100% prosthetic survival rate. Combining the 3.5-mm-diameter NobelActive implants with the All-on-Four concept promises to become a new standard of care for severely compromised patients.
(a) Cone-beam computed tomography (CBCT) views of a severely atrophic mandible. Cross-sectional views are displayed in the lower right portions, and the 3-dimensional (3D) model created from the CBCT scan data is displayed in the lower left. (b) CBCT views and 3D model of a severely atrophic maxilla. (c) CBCT views and 3D model of a severely atrophic mandible with retained teeth.
Figure 2. (a) Preoperative clinical intraoral view of the edentulous maxilla and mandible. (b) Occlusal view of the edentulous maxilla. (c) Occlusal view of the edentulous mandible. Figure 3. (a) Preoperative cone-beam computed tomography (CBCT) view and 3-dimensional (3D) computer model of the maxilla. (b) Preoperative CBCT view and 3D computer model of the mandible.
Figure 4. The severely atrophic mandibular alveolar ridge, with mucoperiosteal flaps reflected. Figure 5. (a) The implants with abutments and healing caps in position in the maxilla. Note the extremely thin alveolar ridge. (b) The implants with abutments and healing caps in position in the mandible. Note the severe horizontal atrophy. Figure 6. (a) The sutured maxillary mucoperiosteal tissues. (b) The sutured mandibular mucoperiosteal tissues.
Figure 7. Postoperative periapical radiographs at 4 months. Figure 8. The definitive maxillary and mandibular fixed prostheses in place. Figure 9. Maxillary and mandibular periapical radiographs at 24 months; note the constant bone levels.
Figure 10. Preoperative cone-beam computed tomography scan and 3-dimensional model of the mandible, showing severe horizontal atrophy. Figure 11. (a) Periapical radiographs 4 months after surgery before fabrication of the definitive prosthesis; note the bone levels. (b) Periapical radiographs 25 months after surgery; note how well the bone levels have been maintained after delivery of the definitive prosthesis.
Figure 12. (a) Preoperative clinical facial view demonstrating the patient's esthetic concerns. (b) Preoperative clinical intraoral view of the existing mandibular dentition. Figure 13. The patient's cone-beam computed tomography scan demonstrated significant horizontal mandibular atrophy. Figure 14. Periapical radiographs 4 months after implant placement.
and 16. Figure 15. (a) Clinical view of the removable maxillary full denture and mandibular All-on-Four fixed prosthesis in place. (b) Clinical view of the patient wearing the final prostheses, demonstrating the improved facial esthetics. Figure 16. Periapical radiographs at 24 months; note the constant bone levels.
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