Effects of Post-Curing Time on the Mechanical and Color Properties of Three-Dimensional Printed Crown and Bridge Materials

Abstract

Three-dimensional (3D) printing is increasingly being utilized in the dental field. After fabricating a prosthesis using a 3D printed resin, a post-curing process is required to improve its mechanical properties, but there has been insufficient research on the optimal post-curing conditions. We used various 3D printed crown and bridge materials in this study, and evaluated the changes in their properties according to post-curing time by evaluating the flexural strength, Weibull modulus, Vickers hardness, color change, degree of conversion, and biocompatibility. The obtained results confirmed that the strength of the 3D printed resin increased when it was post-cured for 60–90 min. The Vickers hardness, the degree of conversion, and biocompatibility of the 3D printed resins increased significantly around the beginning of the post-curing time, and then increased more gradually as the post-curing time increased further. It was observed that the color tone also changed as the post-curing time increased, with some groups showing a ΔE00 value of ≥ 2.25, which can be recognized clinically. This study has confirmed that, after the printing process of a 3D printed resin was completed, a sufficient post-curing time of at least 60 min is required to improve the overall clinical performance of the produced material.

Effects of Postcuring Temperature on the Mechanical Properties and Biocompatibility of Three-Dimensional Printed Dental Resin Material

“…In our study the flexural strength increased abruptly compared with the GS group after 15 min of postcuring. However, another previous study found no significant differences in flexural strength between their GS group and the group with 15 min of postcuring [25]. Moreover, none of the specimens in the present GS group fractured during the three-point bending test, which demonstrates the presence of flow plasticity.…”

“…For measuring the unpolymerize rial, a drop of monomer resin was applied on a microscope slide an measurements were performed on the top surface of each disk, and scans was analyzed. The peak areas for aliphatic and aromatic C=C d and 1608 cm −1 , respectively, were analyzed [25,31]…”

“…Three measurements were performed on the top surface of each disk, and the average of these scans was analyzed. The peak areas for aliphatic and aromatic C=C double bonds at 1638 and 1608 cm −1 , respectively, were analyzed [25,31]. The DC was calculated as follows:…”

“…For these reasons, the postpolymerization process after printing process can play a crucial role in the final outcome. Previous studies have found that postpolymerization is highly dependent on the type of curing chamber, the frequency and intensity of the UV light, the exposure time, and the composition and color of the photosensitive resin, which can potentially affect the mechanical strength and biocompatibility of the 3D printed resin [25], as well as its accuracy [26]. Salmoria et al revealed that thermal curing of the resin used in an SLA 3D printer can reduce the cure heterogeneity and anisotropy [27].…”

Color and Translucency Stability of Three-Dimensional Printable Dental Materials for Crown and Bridge Restorations

“…The post-curing method and time could affect the color of 3D printable materials. Kim et al evaluated the effect of post-curing time on the mechanical and color properties of 3D printable dental materials [ 51 ]. They reported that the color changed as the post-curing time increased and that this would be mainly due to the photoinitiators, as stated earlier in the manuscript.…”