Since I carry around some of those UV-triggered photopolymers around in my mouth (dental resin composite), your post alarmed me somewhat. Here is a relevant article from 2012: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3532765/

TLDR: It depends on how well your dentist handles it, and also what compounds are used. There is cytotoxicity and the known effects of BPA, but you cannot find the word "cancer" in that article. And incriminating compounds are reduced over time ("aging").