Abstract
In this study, five urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% HDD (594), and high-functional aliphatic UA (5812), were selected to formulate five UA-based photopolymer resins for digital light processing (DLP)-based 3D printing. Each UA (40 wt%) was added and blended homogenously with ethoxylated pentaerythritol tetraacrylate (40 wt%), isobornyl acrylate (12 wt%), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (3 wt%), and a pink acrylic (5 wt%). Each UA-based resin specimen was designed using CAD software and fabricated using a DLP 3D printer to specific dimensions. Characteristics, mechanical properties, and cytotoxicity levels of these designed UA-based resins were investigated and compared with a commercial 3D printing denture base acrylic resin (BB base) control group at different UV exposure times. Shore hardness-measurement data and MTT assays were analyzed using a one-way analysis of variance with Bonferroni’s post hoc test, whereas viscosity, maximum strength, and modulus were analyzed using the Kruskal–Wallis test (α = 0.05). UA-based photopolymer resins with tunable mechanical properties were successfully prepared by replacing the UA materials and the UV exposure times. After 15 min of UV exposure, the 5812 and 594 groups exhibited higher viscosities, whereas the 88A and 87A groups exhibited lower viscosities compared with the BB base group. Maximum flexural strength, flexural modulus, and Shore hardness values also revealed significant differences among materials (p < 0.001). Based on MTT assay results, the UA-based photopolymer resins were nontoxic. In the present study, mechanical properties of the designed photopolymer resins could be adjusted by changing the UA or UV exposure time, suggesting that aliphatic urethane acrylate has good potential for use in the design of printable resins for DLP-type 3D printing in dental applications.
Highlights
Ethoxylated pentaerythritol tetraacrylate (PET5EO4A) and 5 urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% hexanediol diacrylate (HDDA) (594), and high-functional aliphatic UA (5812), were purchased from Double Bond Chemical Company (New Taipei City, Taiwan) and used as received
The low viscosity of printable resins is a critical parameter for preventing the formation of bubbles in 3D printed materials [16]
Residual organic solvent, leaching of cytotoxic damage assay results in the present study suggest that the aboveof unreacted monomer, degradation products, and photoinitiators are potential sources mentioned sources of cytotoxicity were negligible
Summary
Complete denture prosthetics, including those made with acrylic denture base resins and artificial teeth, are among the main oral prosthetic devices used to replace a complete arch of missing teeth. Methyl methacrylate (PMMA) is the most commonly used resin in dentistry due to its low density, aesthetics, and cost-effectiveness [1], and can be used to fabricate a denture base through conventional processing techniques such as compression molding, fluid resin pouring, and injection molding [2]. Polymers 2021, 13, 822 used to fabricate a denture base through conventional processing techniques such as compression molding, fluid resin pouring, and injection molding [2]. Maladaptation of dentures has been identified due to considerable polymerization shrinkage and feature distortion processing
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