Department of Removable Prosthodontics, School of Dentistry, National and Kapodistrian University of Athens, Greece.
Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece.
J Prosthodont Res. 2020 Jul;64(3):326-331. doi: 10.1016/j.jpor.2019.09.005. Epub 2019 Sep 30.
To evaluate the different cooling procedures on the mechanical properties of five heat-cured polymethyl methacrylate (PMMA) denture materials.
250 specimens were made equally from Meliodent (ME), Paladon 65 (PA), Probase Hot (PB), Stellon QC-20 (QC) and Vertex Rapid Simplified (VE) implementing five different cooling procedures (n=10/procedure): A) removal from water bath, bench-cooling (10min) and cooling under water (15min), B) remain in water bath till room temperature, C) removal from water bath and cooling in water for 15min, D) removal from water bath and bench cooling till room temperature and E) removal from water bath, bench cooling for 30min and cooling under water for 15min. The specimens were immersed in distilled water (15 days/37ºC) and then subjected to Instrumented Indentation Testing for Martens Hardness (HM), indentation modulus (E) and elastic index (η). Results were statistically analyzed by two- and one-way Analysis of variance (ANOVA) plus Tukey post hoc tests (α=0.05).
The highest values for HM were recorded for QC, PA, VE with B cooling procedure, PB with A and ME with E, for E for QC, PB with A, for PA, VE with B and ME with E, and for η for QC, PB with B, PB with E, ME with C and VE with D.
The cooling procedures recommended for PB resulted in the lowest mechanical properties. A and B may be considered as universal short- and long-cooling procedures respectively providing the highest mechanical properties for the materials tested.
评估五种热固化聚甲基丙烯酸甲酯（PMMA）义齿材料在不同冷却程序下的机械性能。
从 Meliodent（ME）、Paladon 65（PA）、Probase Hot（PB）、Stellon QC-20（QC）和 Vertex Rapid Simplified（VE）中各制作 250 个样本，采用五种不同的冷却程序（n=10/程序）：A）从水浴中取出， bench-cooling（10min）和在水中冷却（15min），B）留在水浴中直至室温，C）从水浴中取出并在水中冷却 15min，D）从水浴中取出并在 bench 上冷却至室温，E）从水浴中取出，在 bench 上冷却 30min，然后在水下冷却 15min。将样本浸入蒸馏水中（15 天/37°C），然后进行压痕硬度（HM）、压痕模量（E）和弹性指数（η）的仪器压痕测试。结果采用双因素和单因素方差分析（ANOVA）加 Tukey 事后检验（α=0.05）进行统计分析。
HM 值最高的是 B 冷却程序下的 QC、PA、VE，A 冷却程序下的 PB，E 冷却程序下的 ME；E 值最高的是 QC、A 冷却程序下的 PB，PA、B 冷却程序下的 VE，ME、E 冷却程序下的 ME；η 值最高的是 QC、B 冷却程序下的 PB，B、E 冷却程序下的 PB，C 冷却程序下的 ME，D 冷却程序下的 VE。
推荐用于 PB 的冷却程序导致机械性能最低。A 和 B 可分别视为通用的短期和长期冷却程序，为测试材料提供最高的机械性能。
