| Autor: |
Jansen van Vuuren, W-A, Miimine, H., Al-Amleh, B., Lyons, K. M., Waddell, J. N. |
| Předmět: |
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| Zdroj: |
New Zealand Dental Journal; Dec2017, Vol. 113 Issue 4, p31-38, 8p |
| Abstrakt: |
Objective: To evaluate the effect of multiple firing cycles on the mechanical properties and microstructure of a lithium disilicate CAD ceramic material. Methods: Ceramic disc specimens (12 x 1.2 mm) were manufactured using lithium disilicate (IPS e.max CAD, Ivoclar, Leichtenstein). The discs were wet-ground with silicon carbide paper, sintered according to the manufacturer's instructions, then divided into five groups. Each group underwent a different number of firing cycles. Biaxial flexural strength tests were performed according to ISO 6872(2008)E. Fracture toughness and hardness were measured using the indentation strength method. XRD diffraction was used to generate information on the crystalline phase content by using a diffractometer and computer software, and colour difference was measured using spectrophotometry. Data was analysed using ANOVA and a two-tailed Students t-test (p = 0.05). Results: Statistical analysis of the results with one-way ANOVA showed no significant difference (p < 0.05) in the mean biaxial flexural strength or fracture toughness between any of the groups tested. XRD analysis showed no noticeable crystalline phase change, nor were there any new crystallites in any of the test groups. Statistical analysis using a two-tailed Students t-test indicated a statistically significant (p < 0.05) and noticeable increase in the yellow chroma of the specimens with increased numbers of thermal cycles. Conclusion. Thermal cycling of IPS e.max CAD appears to have no negative effect on strength or toughness using the protocols presented in this paper, however the chroma may be negatively affected with increased firings. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
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