Can your teeth come to harm when using them to strip thin wire?
Cost of cheap stripper:$5

Cost of crown $1000

Not a great idea though many of us have gotten away with it. In my case I had a bunch of plain copper solid-core telephone wire with polyethylene insulation that stripped very easily (also melted back very easily when soldering). But I've also required dental work from hitting a pit in a dried fruit so I would not advise it. Even if you are not paying directly for it, it's never as good as the original equipment. 

Older wire you find around may not be RoHS and may contain lead in the tinning or if the end has been soldered with PbSn solder.