The effect of thermo-cycling on fracture strength of 3D printing and PMMA interim prostheses

Abstract

Aim of the study: This study compared the fracture resistance of three-dimensional printing (3D) interim restoration with that polymethylmethacrylate (PMMA), interim restoration.
 Materials and methods: In the present study upper molar (dentoform) tooth was prepared for full coverage crowns. The prepared model was digitally scanned by extra-oral scanner. Duplication of the master die into metal dies (chrome cobalt alloy). Totally, 40 samples were divided into two groups (20) using 3D printing (asiga dentatooth resin material), and (20) Polymethylmethacrylate PMMA (integra) resin material. Ten samples from each group were subjected to thermo-cycles (1250 cycles, 5-55 °C). The fracture resistance was then measured for all samples with a universal testing machine.
 Results: In SPSS, the mean ± Stander deviation values of fracture resistance were recorded for the acrylic PMMA group before thermo-cycling (1703.30 ±376.659 Newton) and after thermo-cycling (1460.30 ±364.260 Newton), while the mean ± Stander deviation values were recorded for 3D printing group before thermo-cycling (1972.50±399.181 Newton) and after thermo-cycling ( 2284.10±239.001Newton). It was found that 3D printing recorded a significantly higher fracture resistance mean than PMMA groups.
 Conclusion: 3D printing interim prostheses recorded higher fracture resistance compared with PMMA interim prostheses.