Department of Restorative Dentistry, Araraquara Dental School, São Paulo State University - UNESP, Araraquara, Brazil.
Int Endod J. 2011 Nov;44(11):1019-23. doi: 10.1111/j.1365-2591.2011.01910.x. Epub 2011 Jul 26.
To analyse a method used to evaluate the thermomechanical properties of gutta-percha and Resilon(®) at different temperatures and compression loads.
Two hundred and seventy specimens measuring 10 mm in diameter and 1.5 mm in height were made from the following materials: conventional gutta-percha (GCO), thermoplastic gutta-percha (GTP) and Resilon(®) cones (RE). After 24 h, the specimens were placed in water at 50 °C, 60 °C or 70 °C for 60 s. After that, specimens were placed between two glass slabs, and loads weighing 1.0, 3.0 or 5.0 kg were applied. Images of the specimens were digitized before and after the test and analysed using imaging software to determine their initial and final areas. The thermomechanical property of each material was determined by the difference between the initial and final areas of the specimens. Data were subjected to anova and SNK tests at 5% significance. To verify a possible correlation between the results of the materials, linear regression coefficients (r) were calculated.
Data showed higher flow area values for RE under all compression loads at 70 °C and under the 5.0 kg load at 60 °C (P < 0.05). Regarding gutta-percha, GTP showed higher flow under loads weighing 3.0 and 5.0 kg, at 60 and 70 °C (P < 0.05). GCO presented higher flow at 70 °C with a load of 5.0 kg. Regression analyses showed a poor linear correlation amongst the results of the materials under the different experimental conditions.
Gutta-percha and Resilon(®) cones require different compression loads and temperatures for evaluation of their thermomechanical properties. For all materials, the greatest flow occurred at 70 °C under a load of 5.0 kg; therefore, these parameters may be adopted when evaluating endodontic filling materials.
分析一种用于评估不同温度和压缩负载下牙胶和 Resilon®（瑞特）热机械性能的方法。
从以下材料中制备 270 个直径为 10mm、高度为 1.5mm 的样本：传统牙胶（GCO）、热塑牙胶（GTP）和 Resilon®（RE）牙胶尖。24 小时后，将样本在 50°C、60°C 或 70°C 的水中放置 60 秒。之后，将样本放置在两块玻璃板之间，并施加 1.0、3.0 或 5.0kg 的负载。测试前后对样本进行数字化成像，并使用成像软件分析以确定其初始和最终面积。通过样本初始和最终面积的差异确定每种材料的热机械性能。数据采用方差分析和 SNK 检验进行 5%显著水平的分析。为了验证材料结果之间可能存在的相关性，计算了线性回归系数（r）。
数据显示，在所有压缩负载下，RE 在 70°C 时和在 60°C 时 5.0kg 负载下的流动面积值更高（P<0.05）。关于牙胶，GTP 在 60°C 和 70°C 时，在 3.0kg 和 5.0kg 负载下的流动率更高（P<0.05）。GCO 在 70°C 时，在 5.0kg 负载下的流动率更高。回归分析显示，在不同实验条件下，材料的结果之间线性相关性较差。
牙胶和 Resilon®（瑞特）牙胶尖需要不同的压缩负载和温度来评估其热机械性能。对于所有材料，在 5.0kg 负载下 70°C 时的流动率最大；因此，在评估根管充填材料时可以采用这些参数。
