So far we've tried playing with the toothbrush, watching big sister use toothbrush, brushing her teddies teeth, watching us brush big sister's teeth......and probably more, but I can't think of them right now.
So, currently I'm in fear of all her poor teeth rotting away as despite my best efforts, she won't let me go anywhere near them....so any more suggestions and ideas for cracking this would be really helpful...