Assistant Professor, Department of Advanced Prosthodontics, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Assistant Professor, Department of Advanced Prosthodontics, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
J Prosthet Dent. 2018 May;119(5):840-844. doi: 10.1016/j.prosdent.2017.07.022. Epub 2017 Sep 28.
The polymerization conditions of an autopolymerizing resin affect its physical properties, and at chairside, 3 different methods are commonly used: cooling in cold water, warming in warm water, and heating in hot water. However, the effects of polymerization temperature on the physicomechanical properties of autopolymerizing resin are unclear.
The purpose of this in vitro study was to determine the effect of polymerization temperature on the physicomechanical properties of autopolymerizing resin, including shrinkage, water absorption, surface roughness, amount of residual monomer, and flexural strength.
The experiment was designed to simulate a direct technique commonly used for the fabrication of interim crowns. Autopolymerizing resin specimens were made according to the powder-to-liquid ratio recommended by the manufacturer and soaked in water at 13°C, 37°C, or 60°C for 2 minutes to mold the resin until polymerization was completed 4 minutes after mixing. Shrinkage, water absorption rate, surface roughness, residual monomer, and flexural strength were measured immediately after polymerization and after 1, 3, and 7 days in distilled water at 37°C. Differences among these properties among the 3 different temperatures groups were statistically analyzed by using 1-way ANOVA and the Tukey honest significant difference test (α=.05).
Shrinkage tests showed that the 13°C group had significantly lower shrinkage (P=.004 for 37°C and P<.001 for 60°C) than the other groups immediately after specimen preparation. The 13°C group had significantly higher surface roughness after 0 (P<.001 for 37°C and P<.001 for 60°C), 1 (P=.025 for 37°C and P=.012 for 60°C), 3 (P<.001 for 37°C and P<.001 for 60°C), and 7 days (P<.001 for 37°C and P<.001 for 60°C) than those in the other groups and significantly higher water absorption rates (P=.033 for 37°C and P<.001 for 60°C) than the other groups during the 7 days after fabrication. However, the 13°C group showed significantly higher weight percentage of residual monomers than the 60°C group at 0 (P<.001) and 1 day (P<.001). Finally, 3-point bend tests showed that the 13°C group had significantly lower flexural strength at 0 (P<.001), 1 (P<.001), 3 (P<.001), and 7 days (P<.001) than the other groups.
The temperature environment during dental chairside polymerization of the autopolymerizing resin affected the physicomechanical properties of shrinkage, water absorption rate, surface roughness, residual monomer, and flexural strength.
自聚物树脂的聚合条件会影响其物理性能，在临床中，通常使用 3 种方法：在冷水中冷却、在温水中加热和在热水中加热。然而，聚合温度对自聚物树脂的物理机械性能的影响尚不清楚。
本体外研究的目的是确定聚合温度对自聚物树脂的物理机械性能的影响，包括收缩率、吸水率、表面粗糙度、残余单体量和弯曲强度。
实验设计模拟了一种常用于制作临时冠的直接技术。按照制造商推荐的粉液比制作自聚物树脂试件，并在 13°C、37°C 或 60°C 的水中浸泡 2 分钟，使树脂成型，直至混合后 4 分钟聚合完成。聚合后立即以及在 37°C 的蒸馏水中放置 1、3 和 7 天时，测量收缩率、吸水率、表面粗糙度、残余单体和弯曲强度。使用单因素方差分析和 Tukey 诚实显著差异检验（α=.05）对 3 种不同温度组之间的这些特性进行统计学分析。
收缩率测试表明，与其他组相比，13°C 组在试件制备后立即的收缩率显著降低（37°C 时 P=.004，60°C 时 P<.001）。与其他组相比，13°C 组在 0 小时（37°C 时 P<.001，60°C 时 P<.001）、1 小时（37°C 时 P=.025，60°C 时 P=.012）、3 小时（37°C 时 P<.001，60°C 时 P<.001）和 7 天（37°C 时 P<.001，60°C 时 P<.001）时的表面粗糙度显著更高，吸水率更高（37°C 时 P=.033，60°C 时 P<.001），在制作后 7 天内。然而，与 60°C 组相比，13°C 组在 0 小时（P<.001）和 1 小时（P<.001）时的残余单体重量百分比显著更高。最后，3 点弯曲试验表明，与其他组相比，13°C 组在 0 小时（P<.001）、1 小时（P<.001）、3 小时（P<.001）和 7 天（P<.001）时的弯曲强度显著更低。
自聚物树脂在临床椅旁聚合过程中的温度环境会影响收缩率、吸水率、表面粗糙度、残余单体和弯曲强度等物理机械性能。
