Evaluation of Mechanical and Physical Properties of Light and Heat Polymerized UDMA for DLP 3D Printer.

Qutaiba Alsandi,Yumi Tsuchida,Nobuhiko Yui,Toru Nikaido,Yoshinori Arisaka,Junji Tagami,Masaomi Ikeda,Alireza Sadr

doi:10.3390/s21103331

Abstract

The aims of this study were to investigate the feasibility of using a DLP 3D printer to fabricate a crown using scan data before tooth preparation, and to investigate the effect of additional heat curing on the mechanical properties of the urethane dimethacrylate (UDMA)-based 3D printed crown. A silicone fitting test was used to evaluate the internal adaptation of the crown. For ultimate tensile strength (UTS), the specimens were tested after 24 h storage in water at 37 °C or after 10,000 thermal cycles (TC) between 5–55 °C. For shear bond strength (SBS), a PMMA self-curing resin was filled into a Teflon ring mounted onto the polished UDMA specimens. The internal adaptation of the crowns fabricated with cement space was better than those with no cement space. There was no significant difference in UTS between light-curing and additional heat-curing groups after TC. As for the SBS, there was a significant difference after TC between the two groups. Crowns can be fabricated by a DLP 3D printer using pre-preparation scans with a cement space defined in the software. Additional heat curing of the UDMA-based crown reduced residual monomer and improved its mechanical properties.

Highlights

Digital technology has provided novel methods that are rapidly progressing, presenting new treatment options in dentistry
Models made by the stereolithography (SLA) method are more accurate than those made by digital light processing (DLP), the process of photopolymer curing in DLP printers is considered faster than SLA, since SLA uses a laser light source and DLP
There was a significant difference between the light-cured group (L) and the light- + heat-cured group (L + H) after 24 h distilled water storage (p < 0.05), but no significant difference after 10,000 thermal cycles (TC) (p > 0.05)

Summary

Introduction

Digital technology has provided novel methods that are rapidly progressing, presenting new treatment options in dentistry. Computer-aided design, computer-aided manufacturing (CAD/CAM), three-dimensional (3D) printers, and intra-oral scanners are considered among the popular digital technologies in the dental field [1,2]. Models made by the stereolithography (SLA) method are more accurate than those made by DLP, the process of photopolymer curing in DLP printers is considered faster than SLA, since SLA uses a laser light source and DLP uses a Light Pattern Generator. This method can reach 60 μm of accuracy according to some manufacturer data [6,7]. DLP printers have a digital projector screen used to transfer a single image of each layer across the entire build plate at once [6,8,9]

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