Study of acrylic resins modified by different particles sizes for application in odontology area.

ABSTRACT With the increase in population life expectancy, the search for products with greater durability increases. This leads to search for more and more resistant materials, including in the dental field. Once inorganic particles play a fundamental role in the properties of a composite resin, we searched to evaluate the influence different particles size in its mechanical properties. In these dental resins, we evaluated flexural strength, compressive strength, microhardness Vickers and contraction stress. To avoid unwanted variations, the consistency of these resins did not differ between samples (Consistency Squeeze = 75 N). Besides consistency, other variables of a composite resin (organic matrix composition, initiators, inhibitors) had their amounts fixed, seeking no other influence on the study. Nine types of resins were used in this study, with an average particle size ranging between 0.4μm and 3.0μm, there are three resins composed of single particles (0.4µm, 1.0µm e 3.0 µm) and six resins composed by mixing particles mentioned above. The results were compiled and the data submitted to statistical analysis (ANOVA – Multiple Comparisons Tukey test with 5% significance). The results showed that the synergistic effect of the mixture of particles reflected better properties in compressive strength and flexural strength test as compared to resins with single-size particles. Is possible to conclude too that there is not a single average size range of particles with results superior to other resins in all properties. However, looking for a balance between these properties, samples with an average particle size of 2.02μm and 2.14μm both composed of mixtures of particles (no single particles) showed the best results. As showed by Tukey's statistical analysis, both resins were placed as belonging to the 2 groups that indicate superior properties in all tests.

摘要 随着人口预期寿命的提升，市场对高耐用性产品的需求持续增长，这推动了对更高性能耐材的探索，牙科领域亦不例外。鉴于无机颗粒（inorganic particles）对复合树脂（composite resin）的性能具有决定性作用，本研究旨在探究不同粒径颗粒对其力学性能的影响。针对本研究中的牙科复合树脂，我们检测了弯曲强度（flexural strength）、抗压强度（compressive strength）、维氏显微硬度（Vickers microhardness）以及收缩应力（contraction stress）。为排除无关变量带来的误差，所有样品的树脂稠度保持一致：挤塑稠度（Consistency Squeeze）=75N。除稠度外，复合树脂的其他变量——包括有机基质组成、引发剂与抑制剂——的用量均固定，以排除其对本研究的干扰。本研究共使用9种树脂，其平均粒径范围为0.4μm至3.0μm；其中3种为单一粒径颗粒树脂（粒径分别为0.4μm、1.0μm与3.0μm），剩余6种为上述粒径颗粒混合制备的复合树脂。对实验结果进行汇总后，采用方差分析（ANOVA）结合Tukey多重比较检验进行统计学分析，显著性水平设定为5%。结果表明，与单一粒径颗粒树脂相比，混合粒径颗粒的协同效应可显著提升复合树脂的抗压强度与弯曲强度。此外，本研究还可得出结论：不存在某一单一平均粒径范围的树脂，能在所有性能指标上均优于其他样品。但若追求各项性能的均衡表现，平均粒径为2.02μm与2.14μm的混合粒径树脂（非单一粒径颗粒树脂）则展现出最优的综合性能。经Tukey统计分析验证，这两种树脂均被归入性能最优组别，在所有测试指标中均表现突出。