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Benedikt C. Spies Alexander Fross Erik Adolfsson Aimen Bagegni Sam Doerken Ralf-Joachim Kohal 《Dental materials》2018,34(10):1585-1595
Objective
To investigate the long-term stability of a metal-free zirconia two-piece implant assembled with a carbon fiber-reinforced (CRF) screw by means of transformation propagation, potential changes in surface roughness, the gap size of the implant-abutment connection, and fracture load values.Methods
In a combined procedure, two-piece implants made from alumina-toughened zirconia were dynamically loaded (107 cycles) and hydrothermally aged (85°, 60 days). Implants made from titanium (Ti) and a titanium–zirconium (TiZr) alloy with a titanium abutment screw served as control. Transformation propagation (ATZ) and gap size of the IAC were monitored at cross-sections by scanning electron microscopy (SEM). Furthermore, changes in surface roughness of ATZ implants were measured. Finally, implants were statically loaded to fracture. Linear regression models and pairwise comparisons were used for statistical analyses.Results
Independent of the implant bulk material, dynamic loading/hydrothermal aging did not decrease fracture resistance (p = 0.704). All test and control implants fractured at mean loads >1100 N. Gap size of the IAC remained stable (<5 μm) or decreased. None of the CFR screws fractured during static or dynamic loading. Monoclinic layer thickness of ATZ implants increased by 2–3 μm at surfaces exposed to water, including internal surfaces of the IAC. No changes in surface roughness were observed.Significance
Combined hydrothermal aging and dynamic loading did not affect the above-mentioned parameters of the evaluated two-piece ATZ implant. Mean fracture loads >1100 N suggest a reliable clinical application. 相似文献73.
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Ralf J. Kohal Maria Baechle Jung S. Han Dennis Hueren Ute Huebner Frank Butz 《Clinical oral implants research》2009,20(11):1265-1271
Objectives: Alumina toughening enhances the mechanical properties of zirconia ceramics but the biocompatibility of this material has rarely been addressed. In this study, we examined the osteoblast response to alumina-toughened zirconia (ATZ) with different surface topographies.
Material and methods: Human osteoblasts isolated from maxillary biopsies of four patients were cultured and seeded onto disks of the following substrates: ATZ with a machined surface, airborne-particle abraded ATZ, airborne-particle abraded and acid etched ATZ. Airborne-particle abraded and acid etched titanium (SLA) and polystyrene disks served as a reference control. The surface topography of the various substrates was characterized by profilometry ( Ra , R p−v ) and scanning electron microscopy (SEM). Cell proliferation, cell-covered surface area, alkaline phophatase (ALP) and osteocalcin production were determined. The cell morphology was analyzed on SEM images.
Results: The surface roughness of ATZ was increased by airborne-particle abrasion, but with the Ra and R p−v values showing significantly lower values compared with SLA titanium (Mann-Whitney U-test P <0.05). The proliferation assay revealed no statistically significant differences between the ATZ substrates, SLA titanium and polystyrene (Kruskal–Wallis test, P >0.05). All substrates were densely covered by osteoblasts. ALP and osteocalcin production was similar on the examined surfaces. Cell morphology analysis revealed flat-spread osteoblasts with cellular extensions on all substrates.
Conclusions: These results indicate that ATZ may be a viable substrate for the growth and differentiation of human osteoblasts. Surface modification of ATZ by airborne-particle abrasion alone or in combination with acid etching seems not to interfere with the growth and differentiation of the osteoblasts. 相似文献
Material and methods: Human osteoblasts isolated from maxillary biopsies of four patients were cultured and seeded onto disks of the following substrates: ATZ with a machined surface, airborne-particle abraded ATZ, airborne-particle abraded and acid etched ATZ. Airborne-particle abraded and acid etched titanium (SLA) and polystyrene disks served as a reference control. The surface topography of the various substrates was characterized by profilometry ( R
Results: The surface roughness of ATZ was increased by airborne-particle abrasion, but with the R
Conclusions: These results indicate that ATZ may be a viable substrate for the growth and differentiation of human osteoblasts. Surface modification of ATZ by airborne-particle abrasion alone or in combination with acid etching seems not to interfere with the growth and differentiation of the osteoblasts. 相似文献