Polymerizable compositions that include: (a) a cationically active functional group; (b) an initiation system capable of initiating cationic polymerization of the cationically active functional group; and (c) a filler composition that includes various radiopacifying fillers in an amount sufficient to...http://www.google.com.au/patents/US7160528?utm_source=gb-gplus-sharePatent US7160528 - Radiopaque cationically polymerizable compositions comprising a radiopacifying filler, and method for polymerizing same
