Chemical characterization of additively manufactured methacrylates for dental devices

Abstract

Despite the potential benefits of photopolymerization-based additive manufacturing, photochemical reactions in free-radical polymerization rarely proceed to completion, leading to the accumulation of residual monomer in polymer networks. In this novel study, we examined an array of methacrylate polymers for denture bases (>60 % Bis-EMA and 15–25 % proprietary methacrylic oligomer), orthodontic appliances (>70 % proprietary methacrylic oligomer, <20 % glycol methacrylate and <5 % pentamethyl-piperidyl sebucate) and implant surgical guides (≥75 % Bis-EMA and 30–50 % diurethane dimethacrylate, mixture of isomers) using headspace gas chromatography-mass spectrometry. Experimental data reported herein show that a substantial proportion of chemical compounds observed in the methacrylates decreased with post-illumination and the applied ethanol treatment. In the absence of residual methyl methacrylate, other potentially toxic acrylic esters were observed thus emphasizing the need to thoroughly scrutinize additively manufactured dental devices prior to their use. In the long term, standards for medical devices in dentistry could be revised to reflect the current trends in biomaterials and precursors they are generated from.