not to beat a dead horse but my bruxism caused nerve trauma ---> to nerve death---->root canal (7 to be exact). Not pleasant but ..... so don't discount the mouthguard if you're grinding ....... Also had an experience of a root canal gone bad....pain like i never imagined....and also of a tooth with a "hidden" root....not usual but couldn't be seen with normal x-rays...only discovered when filling the canals and I could feel pain..... ;-)