Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Clin Exp Dent Res. 2023 Oct;9(5):840-850. doi: 10.1002/cre2.763. Epub 2023 Jul 12.
Denture base materials are commonly exposed to different denture cleansers which can affect their essential properties. This study aimed to assess the effect of denture cleansers on color stability and surface roughness of poly methyl methacrylate (PMMA) denture bases fabricated from different techniques: Conventional heat-polymerizing, CAD/CAM additive and CAD/CAM subtractive.
In this in vitro study, 24 disc-shaped specimens were fabricated by the mentioned methods for each group. The initial color and surface roughness of specimens were recorded. The specimens were randomly divided into three subgroups (n = 8): a control subgroup (distilled water), and two experimental subgroups of bioactive oxygen tablet (Corega) and 1% sodium hypochlorite solution. Then they were immersed in the solutions simulating 180 days of clinical use. Color change (∆E) was measured by a spectrophotometer according to the CIE Lab* color space and the American National Bureau of Standards (NBS = 0.92 × ∆E). Final surface roughness was recorded by a profilometer and its change was calculated. The Kruskal-Wallis test followed by the Wilcoxon signed rank test were used for statistical analyses (α = .05).
The conventional and CAD/CAM subtractive groups showed an increase in surface roughness following immersion in hypochlorite solution (p < .05). After immersion in the solutions, the highest surface roughness was noted in the conventional group, and the lowest in the CAD/CAM additive group. The CAD/CAM additive group experienced a significant color change in hypochlorite solution (p < .05) and showed the highest color change while the CAD/CAM subtractive group showed the lowest color change in all denture cleanser solutions.
Although the CAD/CAM additive denture base resins had the lowest surface roughness after exposure to denture cleanser solutions, they showed significant color change, which should be taken into account. Using hypochlorite as a denture cleanser should be cautioned due to its negative effects on the surface roughness and color stability of denture base materials.
义齿基托材料通常会接触不同的义齿清洁剂，这可能会影响其基本性能。本研究旨在评估义齿清洁剂对不同技术制作的聚甲基丙烯酸甲酯（PMMA）义齿基托的颜色稳定性和表面粗糙度的影响：传统热聚合、CAD/CAM 加法和 CAD/CAM 减法。
在这项体外研究中，通过上述方法为每个组制作 24 个圆盘形样本。记录样本的初始颜色和表面粗糙度。将样本随机分为三组（n=8）：对照组（蒸馏水）和两个实验组：生物活性氧片（Corega）和 1%次氯酸钠溶液。然后将它们浸泡在模拟临床使用 180 天的溶液中。使用分光光度计根据 CIE Lab*颜色空间和美国国家标准局（NBS=0.92×∆E）测量颜色变化（∆E）。使用轮廓仪记录最终表面粗糙度，并计算其变化。使用 Kruskal-Wallis 检验后进行 Wilcoxon 符号秩检验进行统计分析（α=0.05）。
传统和 CAD/CAM 减法组在浸入次氯酸钠溶液后表面粗糙度增加（p<0.05）。在浸入溶液后，传统组的表面粗糙度最高，CAD/CAM 加法组的表面粗糙度最低。CAD/CAM 加法组在次氯酸钠溶液中经历了显著的颜色变化（p<0.05），而 CAD/CAM 减法组在所有义齿清洁剂溶液中显示出最低的颜色变化。
尽管 CAD/CAM 加法义齿基托树脂在暴露于义齿清洁剂溶液后具有最低的表面粗糙度，但它们显示出显著的颜色变化，这一点应该考虑到。由于次氯酸钠对义齿基托材料的表面粗糙度和颜色稳定性有负面影响，因此应谨慎使用其作为义齿清洁剂。
