Clin Oral Implants Res. 2021 Aug 5. doi: 10.1111/clr.13825. Online ahead of print.
ABSTRACT
OBJECTIVE: To evaluate the influence of artificial aging on the transformation propagation and fracture resistance of zirconia implants.
METHODS: One- [with integrated implant abutment, 1P; regular diameter (4.1mm); n=16] and two-piece [with separate implant abutment, 2P; wide diameter (5mm); n=16] zirconia implants were embedded according to ISO 14801. A two-piece titanium-zirconium implant (Ti-Zr; 4.1mm diameter) served as a control (n=16). One subgroup (n=8) of each system was simultaneously dynamically loaded (107 cycles; 98N) and hydrothermally aged (85°C, 58 days) while the other subgroup (n=8) remained untreated. Finally, specimens were statically loaded to fracture. Potential crystal phase transformation was examined at cross-sections using scanning electron microscopy (SEM). A multivariate linear regression model was applied for statistical analyses.
RESULTS: The fracture resistance of 1P [1117 (SD = 38) N; loaded/aged: 1009 (60) N], 2P [850 (36) N; loaded/aged: 799 (84) N] and Ti-Zr implants [1338 (205) N; loaded/aged: 1319 (247) N] was not affected significantly by loading/aging (p=0.171). However, when comparing the systems, they revealed significant differences independent of loading/aging (p≤0.001). Regarding the crystal structure, a transformation zone was observed in SEM images of 1P only after aging, while 2P showed a transformation zone even before aging. After hydrothermal treatment, an increase of this monoclinic layer was observed in both systems.
CONCLUSIONS: The Ti-Zr control implant showed higher fracture resistance compared to both zirconia implants. Loading/aging had no significant impact on the fracture resistance of both zirconia implants. The wide body 2P zirconia implant was weaker than the regular body 1P implant.
PMID:34352139 | DOI:10.1111/clr.13825
