Fatigue Performance of the On1 Restorative System
Objectives: The On1TM restorative concept uses a final abutment base installed at surgery while maintaining restorative flexibility. This two-piece abutment raises the prosthetic interface from bone to tissue level leaving the soft tissue undisturbed for all prosthetic restorative steps. Although comparative reports are few, fatigue resistance was higher for a 2-piece vs 1-piece zirconia abutment system. This study evaluates and compares fatigue performance of the On1 restorative system to 1-piece systems in clinical use.
Methods: Fatigue performance of the On1 1.75 mm base narrow (NP) and regular platform (RP) systems on conical connection (CC) implants was assessed according to ISO 14801. Results were compared with NP and RP one-piece titanium abutments (TI-snappy) on CC and zirconia abutments (ZI-NobelProcera) on internal tri-channel connection implants. Maximum load levels of NP and RP groups were compared using Kaplan-Meier test.
Results: The fatigue limit of On1 NP ZI exceeded On1 NP TI, therefore TI systems were selected as worst case scenario for analysis. The fatigue limit of the On1 TI NP and RP was 205N and 250N, respectively. The median fatigue limit of On1 TI NP was 24% and RP was 34% greater than the reference one-piece ZI system. Maximum load levels of the two-piece system were lower than the one-piece TI system in both NP (p<0.01) and RP (p<0.05). On1 maximum load levels outperformed the one-piece ZI system significantly in fatigue performance for both NP (p<0.001) and RP (p=0.004).
Conclusions: The On1 restorative system demonstrated good fatigue resistance. Its fatigue performance was superior to a well-documented one-piece zirconia abutment system with proven long-term clinical performance. The On1 restorative concept provides sufficient strength while preserving both soft tissue attachment and restorative flexibility.