Cytotoxicity, Colour Stability and Dimensional Accuracy of 3D Printing Resin with Three Different Photoinitiators

Abstract

Biocompatibility is important for the 3D printing of resins used in medical devices and can be affected by photoinitiators, one of the key additives used in the 3D printing process. The choice of ingredients must be considered, as the toxicity varies depending on the photoinitiator, and unreacted photoinitiator may leach out of the polymerized resin. In this study, the use of ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) as a photoinitiator for the 3D printing of resin was considered for application in medical device production, where the cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical/physical properties were evaluated. Along with TPO-L, two conventional photoinitiators, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), were considered. A total of 0.1 mol% of each photoinitiator was mixed with the resin matrix to prepare a resin mixture for 3D printing. The specimens were printed using a direct light processing (DLP) type 3D printer. The 3D-printed specimens were postprocessed and evaluated for cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical properties in accordance with international standards and the methods described in previous studies. The TPO-L photoinitiator showed excellent biocompatibility and colour stability and possessed with an acceptable dimensional accuracy for use in the 3D printing of resins. Therefore, the TPO-L photoinitiator can be sufficiently used as a photoinitiator for dental 3D-printed resin.

Development of Bisphenol-A-Glycidyl-Methacrylate- and Trimethylolpropane-Triacrylate-Based Stereolithography 3D Printing Materials

“…Toxicity and biocompatibility testing are also critical when using 3D-printed structures in medical applications. Industrial applications require excellent mechanical properties to withstand pressure and impacts [ 32 , 45 ].…”

Photo-Curing Kinetics of 3D-Printing Photo-Inks Based on Urethane-Acrylates

“…TPOL as a photoinitiator was added to the formulations at 1 wt.% regarding the total weight of the monomers. TPOL has previously shown excellent biocompatibility, color stability, and 3D-printing accuracy compared to common photoinitiators, i.e., bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) and (2,4,6-Trimethylbenzoyl)diphenylphosphine oxide (TPO) [ 25 , 26 , 27 ].…”

3D-Printed Microarray Patches for Transdermal Applications

“…With the integration of additive manufacturing and bioapplications such as MAPs, it is critical that further investigation into biocompatible photoinitiators is pursued. Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate is being explored as a potential biocompatible photoinitiator candidate for use in dental resins . UV absorbers are also a critical component of resin formulation, particularly for higher resolution printing applications.…”

“…Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate is being explored as a potential biocompatible photoinitiator candidate for use in dental resins. 93 UV absorbers are also a critical component of resin formulation, particularly for higher resolution printing applications. UV absorber dyes commonly employed in consumer settings, such as 2,5-thiophenediylbis(5- tert -butyl-1,3-benzoxazole), which is used in tissue products, could be promising candidates for biocompatible UV absorbers in resin development.…”