A dental appliance made of an olefin polymer is directly formed via rapid prototyping without the use of an intermediary physical mold. A polymer precursor solution includes one or more olefin-containing monomers and/or oligomers, an olefin polymerization catalyst, and a UV absorbing agent to limit penetration of the UV light through the polymer precursor solution. One or more reactions of the polymer precursor solution are modulated in response to UV light, and the polymer precursor solution may further include an inhibitor (quenching agent) configured to modulate those reactions. The polymer precursor solution can be deposited using UV-cured stereolithographic or 3D printing methods to form appliances exhibiting improved elongation at break characteristics and suitable stress resistance.
