Giorgi Maria Cecília Caldas, Lima Débora Alves Nunes Leite, Marchi Giselle Maria, Ambrosano Gláucia Maria, Aguiar Flávio Henrique Baggio
Department of Restorative Dentistry Piracicaba Dental School, University of Campinas, Piracicaba-SP, Brazil.
Department of Social Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba-SP, Brazil.
Eur J Dent. 2014 Jan;8(1):9-14. doi: 10.4103/1305-7456.126233.
This study analyzed the influences of the light-activation protocol and softening test on the degree of conversion (DC) and Knoop Hardness (KHN) of a microhybrid resin composite.
Filtek Z250 (3M ESPE) was light-activated with a third-generation light-emitting diode (Valo Ultradent) by three protocols - standard, high power, and plasma emulation - or with a quartz-tungsten halogen XL 3000 (3M ESPE) in conventional mode. All modes were set to deliver 19 J/cm(2). The DC (N = 20) was determined by Fourier transform infrared spectrometry on the top (T) and bottom (B) surfaces. For the KHN test, samples were subdivided in four groups (n = 5 each) according to the storage media: absolute ethanol, 75% ethanol, distilled water, and air (control group). The KHN values were evaluated on T and B before and 24 h after immersion in the storage media. Data were analyzed by split-plot analysis of variance (ANOVA; for DC) or repeated-measures split-plot ANOVA (for KHN), followed by Tukey's test (α = 0.05).
For the DC, the light-activation protocol did not influence the results and there was no difference between T and B. For the KHN test, the light-activation protocol did not influence the results and T showed higher microhardness values than B for all experimental conditions. There were significant differences in KHN depending on the storage media. Samples immersed in absolute ethanol generally presented lower KHN values, with no differences compared to samples in 75% ethanol.
The storage media affected the outcomes of the softening test.
本研究分析了光激活方案和软化试验对微混合树脂复合材料转化率（DC）和努氏硬度（KHN）的影响。
Filtek Z250（3M ESPE）通过三种方案——标准、高功率和等离子体模拟——用第三代发光二极管（Valo Ultradent）进行光激活，或以常规模式用石英钨卤素XL 3000（3M ESPE）进行光激活。所有模式均设置为提供19 J/cm²。通过傅里叶变换红外光谱法在顶部（T）和底部（B）表面测定DC（N = 20）。对于KHN测试，根据储存介质将样品分为四组（每组n = 5）：无水乙醇、75%乙醇、蒸馏水和空气（对照组）。在浸入储存介质之前和之后24小时，在T和B上评估KHN值。数据通过方差分析的裂区分析（用于DC）或重复测量的裂区方差分析（用于KHN）进行分析，随后进行Tukey检验（α = 0.05）。
对于DC，光激活方案不影响结果，T和B之间没有差异。对于KHN测试，光激活方案不影响结果，并且在所有实验条件下，T的显微硬度值均高于B。根据储存介质的不同，KHN存在显著差异。浸入无水乙醇中的样品通常呈现较低的KHN值，与浸入75%乙醇中的样品相比没有差异。
储存介质影响软化试验的结果。
