IADR Abstract Archives
Material Characterization of Surface-Modified Toughened Zirconia for Enhanced Osseointegration Potential
Objectives: To evaluate phase composition, microstructure and hardness of yttria- and ceria-stabilized zirconia exposed to three surface-modification techniques.
Methods: One commercial 3mol% yttria-stabilized zirconia (3Y-TZP, TZ-3Y-E, Tosoh) containing 0.25wt% Al2O3 and one lab-made 10mol% ceria-stabilized zirconia (Ce-TZP) containing 0.25wt% Al2O3 doped with 0.2mol% CaO were studied. Zirconia powders were cold isostatically pressed to disks, pressureless sintered (3Y-TZP at 1350°C, Ce-TZP at 1250°C, 2h) and mirror-polished. Each zirconia grade was exposed to: (1) sandblasting (Al2O3, 110 µm, 4.5 bar), (2) acid-etching (20% HF, 2h), (3) sandblasting + acid-etching, and (4) mirror-polishing (control). Density was determined according to the Archimedes principle; phase composition was characterized using X-ray diffraction (XRD); surface roughness (Sa) was measured using optical confocal microscopy and microstructure was analyzed using scanning electron microscopy (SEM). Surface wettability (hydrophilicity) was measured using a static sessile-drop test, while also Vickers hardness was assessed. Statistics involved one-way ANOVA and post-hoc Games-Howell test (α=0.05).
Results: Ce-TZP revealed higher density than 3Y-TZP (6.215 vs. 6.055g/cm3). Sandblasting with/without acid-etching increased monoclinic phase for both 3Y-TZP (≈10wt%) and Ce-TZP (≈42wt%) zirconia. Mirror-polished 3Y-TZP and Ce-TZP showed the lowest roughness (Sa: 0.0081 µm and 0.0078 µm) followed by acid-etching (0.041 µm and 0.038 µm) and sandblasting with/without acid-etching 3Y-TZP (0.88/0.88 µm) and Ce-TZP (1.24/1.18 µm). SEM revealed irregular surfaces after sandblasting and small pits <1 µm between zirconia grains after acid-etching both zirconia grades. Sandblasting, acid-etching and sandblasting + acid-etching significantly increased zirconia hydrophilicity (θ: 67.8°, 54.7° and 29°) in comparison to mirror-polished 3Y-TZP (78.6°). Sandblasting with/without acid-etching both zirconia grades revealed a significantly higher hardness compared to polished and etched disks.
Conclusions: Sandblasting with/without acid-etching can help increasing surface roughness, hydrophilicity and hardness of 3Y-TZP and Ce-TZP but also cause high transformation toughening in Ce-TZP, which can be beneficial properties in zirconia implantology.
Methods: One commercial 3mol% yttria-stabilized zirconia (3Y-TZP, TZ-3Y-E, Tosoh) containing 0.25wt% Al2O3 and one lab-made 10mol% ceria-stabilized zirconia (Ce-TZP) containing 0.25wt% Al2O3 doped with 0.2mol% CaO were studied. Zirconia powders were cold isostatically pressed to disks, pressureless sintered (3Y-TZP at 1350°C, Ce-TZP at 1250°C, 2h) and mirror-polished. Each zirconia grade was exposed to: (1) sandblasting (Al2O3, 110 µm, 4.5 bar), (2) acid-etching (20% HF, 2h), (3) sandblasting + acid-etching, and (4) mirror-polishing (control). Density was determined according to the Archimedes principle; phase composition was characterized using X-ray diffraction (XRD); surface roughness (Sa) was measured using optical confocal microscopy and microstructure was analyzed using scanning electron microscopy (SEM). Surface wettability (hydrophilicity) was measured using a static sessile-drop test, while also Vickers hardness was assessed. Statistics involved one-way ANOVA and post-hoc Games-Howell test (α=0.05).
Results: Ce-TZP revealed higher density than 3Y-TZP (6.215 vs. 6.055g/cm3). Sandblasting with/without acid-etching increased monoclinic phase for both 3Y-TZP (≈10wt%) and Ce-TZP (≈42wt%) zirconia. Mirror-polished 3Y-TZP and Ce-TZP showed the lowest roughness (Sa: 0.0081 µm and 0.0078 µm) followed by acid-etching (0.041 µm and 0.038 µm) and sandblasting with/without acid-etching 3Y-TZP (0.88/0.88 µm) and Ce-TZP (1.24/1.18 µm). SEM revealed irregular surfaces after sandblasting and small pits <1 µm between zirconia grains after acid-etching both zirconia grades. Sandblasting, acid-etching and sandblasting + acid-etching significantly increased zirconia hydrophilicity (θ: 67.8°, 54.7° and 29°) in comparison to mirror-polished 3Y-TZP (78.6°). Sandblasting with/without acid-etching both zirconia grades revealed a significantly higher hardness compared to polished and etched disks.
Conclusions: Sandblasting with/without acid-etching can help increasing surface roughness, hydrophilicity and hardness of 3Y-TZP and Ce-TZP but also cause high transformation toughening in Ce-TZP, which can be beneficial properties in zirconia implantology.