Effects of ageing on surface textures of veneering ceramics for zirconia frameworks

Objectives: To evaluate the effects of ageing on surface textures of veneering ceramics for zirconia frameworks.

Methods: Five different veneering ceramics for zirconia frameworks, Vintage ZR (ZR), Cerabien ZR (CZR), VitaVM9 (VM9), Cercon ceram KISS (KISS), and IPS e.max ceram (e.max), and one veneering ceramic with metal frameworks, Vintage MP (MP), were evaluated. Twenty specimens were fabricated from each veneering ceramic. All specimens were divided into two groups, one of which was subjected to accelerated ageing. The other was used as the control. Accelerated ageing was performed on the distilled water for 5h at 200°C and 2 atm. Surface textures were examined using laser profilometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS).

Results: Compared to unaged specimens, surface roughness parameters (Ra, Rp, Rv) of all aged specimens except e.max were significantly greater (P=0.000). Compared to the unaged specimens, sodium and potassium on the surfaces of all the aged specimens significantly decreased (P<0.05). However, oxygen levels increased significantly (P<0.05). Silicon showed a tendency to decrease in all aged specimens, and that of ZR, KISS and e.max have a significant decrease (P<0.01). Numerous ruffled cracks were observed on the surfaces of all aged specimens, as shown by SEM. The peaks of all crystalline phases on the surfaces of all specimens changed after accelerated ageing.

Conclusion: Surface textures of all examined veneering ceramics were changed by the accelerated ageing test.