Cumulative Survival Rate
The registered 100% implant cumulative survival rate (CSR) of the present study is comparable to recent publications for the All-on-4 concept. Maló et al. (2019) reported three-year CSR of 97.8% and 99.1% for the maxilla and mandible. Furthermore, a systematic review evaluating the All-on-4 treatment concept registered a 99.8% implant CSR for All-on-4 restorations with a follow-up of two or more years.
Marginal Bone Loss
The mean marginal bone loss (MBL) at three years of follow-up demonstrated the stability of the rehabilitations over this period, as compared to the difference of 0.03 mm of mean MBL registered in the previous one-year report. Moreover, the MBL recorded in the present study at three years compares favorably with previous studies reporting a range of 1.06–1.52 mm for the maxilla and 1.30 mm overall for both maxilla and mandible. In a systematic review comparing marginal bone loss between axial and tilted implant-supported fixed prosthetic reconstructions, a range of 0.91–1.55 mm and 0.72–1.67 mm was registered after three years of follow-up of full-arch restorations for axial and tilted implants, respectively (data extracted from study). The potential explanation of this lower MBL could be associated with PEEK’s characteristics of shock absorption, given its 1200 N cut-off point for plastic deformation (important in load-bearing areas).
-Nobre et al., Hybrid Polyetheretherketone (PEEK)–Acrylic Resin Prostheses and the All-on-4 Concept: A Full-Arch Implant-Supported Fixed Solution with 3 Years of Follow-Up, J of Clin. Med., 2020.