The NobelGuide^® All-on-4^® Treatment Concept for Rehabilitation of Edentulous Jaws: A Retrospective Report on the 7-Years Clinical and 5-Years Radiographic Outcomes

Background: There is a necessity of studies documenting the long-term outcome of full-arch flapless rehabilitations.

Purpose: To evaluate the 7 years implant and prosthesis survival rate and 5-years marginal bone loss of full-arch fixed prosthetic rehabilitations supported by implants in immediate function with the All-on-4^® treatment concept using a computer guided surgical protocol (NobelGuide^® , Nobel Biocare).

Materials and methods: This retrospective clinical study included 111 edentulous patients (n = 53 bruxers; n = 21 smokers; n = 59 systemically compromised), rehabilitated between February 2005 and November 2010 with 532 implants with the All-on-4^® treatment concept using NobelGuide^® . Outcome measures were implant and prosthesis survival, marginal bone loss at 5-years and the incidence of mechanical and biological complications. Survival was calculated using life-table analysis. Inferential analysis was performed to compare the difference in marginal bone loss between axial and tilted implants.

Results: Sixteen patients were lost to follow-up. The implant cumulative survival rate was 94.5% at 7 years. Prosthetic survival was 97.8% (n = 3 prosthetic failures). The average (standard deviation) marginal bone loss at 5 years was 1.3 mm (1.06 mm) overall, 1.27 mm (1.02 mm) for tilted implants and 1.34 mm (1.1 mm) for axial implants (p < .001). Ninety-one patients experienced complications in the provisional prostheses (n = 47 patients who were bruxers; n = 25 patients with implant-supported rehabilitation as opposing dentition) ranging from prosthetic fracture (n = 66 patients) to abutment or prosthetic screw loosening (n = 74 patients). Thirty-three patients experienced complications in the definitive prostheses (all exclusive to patients who were bruxers or had implant-supported rehabilitations as opposing dentition) ranging from acrylic-resin prosthetic/crown fracture (n = 23 patients) to abutment or prosthetic screw loosening (n = 10 patients). Twenty-five patients (22%) registered peri-implant pathology.

Conclusions: Within the limitations of this study, it is possible to conclude that this treatment modality for completely edentulous jaws is possible with high long-term survival outcomes. Bruxing and smoking habits had a negative impact on implant failure, mechanical, and biological complications.