R.K.
Hi L.. My 21 month old used to do this all the time especially when teething. I can't stand the noise and it was brought to my attention that even though I wasn't making a big deal I was reacting to it without even realizing it so if she realized she gets some sort of reaction out of you by grinding her teeth if you completly ignore it that includes any type of gasping sound or other reaction facial or noise she may stop doing it. It is completly normal for babies and toddlers to grind their teeth as they come in you need to be concerned if she is doing it while sleeping though.