Digholkar Shruti, Madhav V N V, Palaskar Jayant
Private Practitioner, Pune, Maharashtra, India.
D. Y. Patil Dental School, Pune, Maharashtra, India.
J Indian Prosthodont Soc. 2016 Oct-Dec;16(4):328-334. doi: 10.4103/0972-4052.191288.
The purpose of this study was to evaluate and compare the flexural strength and microhardness of provisional restorative materials fabricated utilizing rapid prototyping (RP), Computer Assisted Designing and Computer Assisted Milling (CAD-CAM) and conventional method.
Twenty specimens of dimensions 25 mm × 2 mm × 2 mm (ADA-ANSI specification #27) were fabricated each using: (1) Three dimensional (3D) printed light-cured micro-hybrid filled composite by RP resin group, (2) a milled polymethyl methacrylate (CH) using CAD-CAM (CC resin group), and (3) a conventionally fabricated heat activated polymerized CH resin group. Flexural strength and microhardness were measured and values obtained were evaluated.
The measured mean flexural strength values (MegaPascals) were 79.54 (RP resin group), 104.20 (CC resin group), and 95.58 (CH resin group). The measured mean microhardness values (Knoop hardness number) were 32.77 (RP resin group), 25.33 (CC resin group), and 27.36 (CH resin group). The analysis of variance (ANOVA) test shows that there is statistically significant difference in the flexural strength values of the three groups ( < 0.05). According to the pairwise comparison of Tukey's honest significant difference (HSD) test, flexural strength values of CC resin group and CH resin group were higher and statistically significant than those of the RP resin group ( < 0.05). However, there was no significant difference between flexural strength values of CC resin and CH resin group ( = 0.64). The difference in microhardness values of the three groups was statistically significant according to ANOVA as well as the intergroup comparison done using the Tukey's HSD () test ( < 0.05).
CC-based CH had the highest flexural strength whereas RP-based 3D printed and light cured micro-hybrid filled composite had the highest microhardness.
本研究旨在评估和比较使用快速成型（RP）、计算机辅助设计与计算机辅助加工（CAD-CAM）以及传统方法制作的临时修复材料的抗弯强度和显微硬度。
制作20个尺寸为25毫米×2毫米×2毫米（ADA-ANSI规范#27）的试件，每组各制作20个：（1）通过RP树脂采用三维（3D）打印的光固化微混合填充复合材料（RP树脂组），（2）使用CAD-CAM铣削的聚甲基丙烯酸甲酯（CH）（CC树脂组），以及（3）传统制作的热活化聚合CH树脂组。测量抗弯强度和显微硬度，并对所得值进行评估。
测得的平均抗弯强度值（兆帕斯卡）分别为79.54（RP树脂组）、104.20（CC树脂组）和95.58（CH树脂组）。测得的平均显微硬度值（努氏硬度数）分别为32.77（RP树脂组）、25.33（CC树脂组）和27.36（CH树脂组）。方差分析（ANOVA）测试表明，三组的抗弯强度值存在统计学显著差异（P<0.05）。根据Tukey真实显著差异（HSD）检验的两两比较，CC树脂组和CH树脂组的抗弯强度值高于RP树脂组且具有统计学显著性（P<0.05）。然而，CC树脂组和CH树脂组的抗弯强度值之间没有显著差异（P = 0.64）。根据ANOVA以及使用Tukey HSD（P）检验进行的组间比较，三组的显微硬度值差异具有统计学显著性（P<0.05）。
基于CC的CH具有最高的抗弯强度，而基于RP的3D打印光固化微混合填充复合材料具有最高的显微硬度。
