National and Kapodistrian University of Athens, School of Dentistry, Department of Prosthodontics, Athens, Greece.
National and Kapodistrian University of Athens, School of Dentistry, Department of Biomaterials, Greece.
J Appl Oral Sci. 2022 Jul 22;30:e20220161. doi: 10.1590/1678-7757-2022-0161. eCollection 2022.
To evaluate the amount of methyl methacrylate (MMA) released in water from heat-cured polymethyl methacrylate (PMMA) denture base materials subjected to different cooling procedures.
Disk-shaped specimens (Ø:17 mm, h:2 mm) were fabricated from Paladon 65 (PA), ProBase Hot (PB), Stellon QC-20 (QC) and Vertex Rapid Simplified (VE) denture materials using five different cooling procedures (n=3/procedure): A) Bench-cooling for 10 min and then under running water for 15 min; B) Cooling in water-bath until room temperature; C) Cooling under running water for 15 min; D) Bench-cooling, and E) Bench-cooling for 30 min and under running water for 15 min. A, B, D, E procedures were proposed by the manufacturers, while the C was selected as the fastest one. Control specimens (n=3/material) were fabricated using a long polymerization cycle and bench-cooling. After deflasking, the specimens were ground, polished and stored in individual containers with 10 ml of distilled water for seven days (37oC). The amount of water-eluted MMA was measured per container using isocratic ultra-fast liquid chromatography (UFLC). Data were analyzed using Student's and Welch's t-test (α=0.05).
MMA values below the lower quantification limit (LoQ=5.9 ppm) were registered in B, C, E (PA); E (PB) and B, D, E (QC) procedures, whereas values below the detection limit (LoD=1.96 ppm) were registered in A, D (PA); A, B, C, D (PB); C, D, E (VE) and in all specimens of the control group. A, B (VE) and A, C (QC) procedures yielded values ranging from 6.4 to 13.2 ppm with insignificant differences in material and procedure factors (p>0.05).
The cooling procedures may affect the monomer elution from denture base materials. The Ε procedure may be considered a universal cooling procedure compared to the ones proposed by the manufacturers, with the lowest residual monomer elution in water.
评估不同冷却程序下热固性聚甲基丙烯酸甲酯（PMMA）义齿基托材料在水中释放的甲基丙烯酸甲酯（MMA）量。
使用五种不同的冷却程序（n=3/程序）从 Paladon 65（PA）、ProBase Hot（PB）、Stellon QC-20（QC）和 Vertex Rapid Simplified（VE）义齿材料中制备出直径为 17 毫米、厚度为 2 毫米的圆盘状试件：A）在台面上冷却 10 分钟，然后在流水下冲洗 15 分钟；B）在水浴中冷却至室温；C）在流水下冲洗 15 分钟；D）在台面上冷却；E）在台面上冷却 30 分钟，然后在流水下冲洗 15 分钟。程序 A、B、D、E 是由制造商提出的，而程序 C 是选择的最快的程序。对照组试件（n=3/材料）使用长聚合周期和台面上冷却制备。脱模后，将试件研磨、抛光，并储存在装有 10ml 蒸馏水的单独容器中，在 37°C 下保存 7 天。使用等度超快速液相色谱（UFLC）测量每个容器中水溶出 MMA 的量。数据采用学生 t 检验和 Welch 检验（α=0.05）进行分析。
程序 B、C、E（PA）；E（PB）和 B、D、E（QC）中记录的 MMA 值低于定量下限（LoQ=5.9ppm），而程序 A、D（PA）；A、B、C、D（PB）；C、D、E（VE）以及对照组的所有试件中记录的 MMA 值低于检测限（LoD=1.96ppm）。程序 A、B（VE）和 A、C（QC）产生的 MMA 值在 6.4 到 13.2ppm 之间，在材料和程序因素方面无显著差异（p>0.05）。
冷却程序可能会影响义齿基托材料中单体的洗脱。与制造商提出的程序相比，E 程序可以被认为是一种通用的冷却程序，在水中残留的单体洗脱量最低。
