Bauer Henrik, Ilie Nicoleta
Department of Restorative Dentistry, Dental School of the Ludwig-Maximilians-University, Goethestr, 70, 80336 Munich, Germany.
Dent Mater J. 2013;32(4):592-9. doi: 10.4012/dmj.2012-309.
This study investigated the effects of aging and irradiation time on the macro- and micro-mechanical properties of a highly translucent nanohybrid composite (IPS Empress Direct, Trans Opal shade, Ivoclar Vivadent). Flexural strength, flexural modulus, indentation modulus, Vickers hardness, and creep were measured after being irradiated with different durations (5, 10, 20, and 40 s) and aged under different conditions (24 h at 37°C in water; 5,000 times of thermocycling between 5°C and 55°C followed by 4-week storage in artificial saliva or alcohol). Rate of cure was also measured for these four irradiation times at composite specimen surface and at 2 mm depth. Effects of aging and irradiation time were statistically analyzed using one-way ANOVA with Tukey's HSD post hoc test (α=0.05), partial eta-squared statistic, and Weibull analysis. Alcohol aging significantly reduced the mechanical properties. Aging in saliva produced a positive effect on micro-mechanical properties. Irradiation time should be at least 20 s to yield favorable mechanical properties.
本研究调查了老化和辐照时间对一种高透明度纳米混合复合材料（义获嘉全瓷直接修复体，透明白色，义获嘉威瓦登特公司）的宏观和微观力学性能的影响。在用不同持续时间（5、10、20和40秒）进行辐照并在不同条件下老化（在37°C水中24小时；在5°C和55°C之间进行5000次热循环，随后在人工唾液或酒精中储存4周）后，测量了弯曲强度、弯曲模量、压痕模量、维氏硬度和蠕变。还测量了这四个辐照时间下复合材料试样表面和2毫米深度处的固化速率。使用单因素方差分析和Tukey's HSD事后检验（α = 0.05）、偏η²统计量和威布尔分析对老化和辐照时间的影响进行了统计分析。酒精老化显著降低了力学性能。在唾液中老化对微观力学性能产生了积极影响。辐照时间应至少为20秒才能产生良好的力学性能。
