Effect of different solutions on color stability of acrylic resin-based dentures

The aim of this study was to evaluate the effect of thermocycling and immersion in mouthwash or beverage solutions on the color stability of four different acrylic resin-based dentures (Onda Cryl, OC; QC20, QC; Classico, CL; and Lucitone, LU). The factors evaluated were type of acrylic resin, immersion time, and solution (mouthwash or beverage). A total of 224 denture samples were fabricated. For each type of resin, eight samples were immersed in mouthwashes (Plax-Colgate, PC; Listerine, LI; and Oral-B, OB), beverages (coffee, CP; cola, C; and wine, W), and artificial saliva (AS; control). The color change (DE) was evaluated before (baseline) and after thermocycling (T1), and after immersion in solution for 1 h (T2), 3 h (T3), 24 h (T4), 48 h (T5), and 96 h (T6). The CIE Lab system was used to determine the color changes. The thermocycling test was performed for 5000 cycles. Data were submitted to three-way repeated-measures analysis of variance and Tukey's test (p < 0.05). When the samples were immersed in each mouthwash, all assessed factors, associated or not, significantly influenced the color change values, except there was no association between the mouthwash and acrylic resin. Similarly, when the samples were immersed in each beverage, all studied factors influenced the color change values. In general, regardless of the solution, LU exhibited the greatest DE values in the period from T1 to T5; and QC presented the greatest DE values at T6. Thus, thermocycling and immersion in the various solutions influenced the color stability of acrylic resins and QC showed the greatest color alteration.

本研究旨在评估热循环（thermocycling）以及浸泡于漱口水或饮品溶液中，对四种不同丙烯酸树脂基义齿（Onda Cryl，OC；QC20，QC；Classico，CL；Lucitone，LU）的颜色稳定性的影响。本次评估的因素包括丙烯酸树脂类型、浸泡时长以及溶液种类（漱口水或饮品）。总共制备了224个义齿样本。针对每种树脂，选取8个样本分别浸泡于三类漱口水（高露洁Plax（Plax-Colgate），PC；李施德林（Listerine），LI；欧乐-B（Oral-B），OB）、三类饮品（咖啡，CP；可乐，C；葡萄酒，W）以及人工唾液（AS；对照组）中。

分别于基线（baseline）、热循环处理后（T1）、溶液浸泡1小时（T2）、3小时（T3）、24小时（T4）、48小时（T5）及96小时（T6）后，对颜色变化值（DE）进行评估。采用CIE Lab系统测定颜色变化。热循环实验共执行5000次循环。

数据采用三因素重复测量方差分析与Tukey检验进行统计学处理（p < 0.05）。当样本浸泡于各类漱口水时，除漱口水类型与丙烯酸树脂类型之间无显著关联外，所有评估因素（单独或联合作用）均对颜色变化值产生显著影响。与之类似，当样本浸泡于各类饮品时，所有研究因素均对颜色变化值存在显著影响。

总体而言，无论使用何种溶液，在T1至T5的观测时间段内，LU均表现出最大的DE值；而在T6时间点，QC的DE值最大。综上，热循环及各类溶液浸泡均会显著影响丙烯酸树脂的颜色稳定性，其中QC的颜色改变程度最为显著。