My 19 month old toddler keeps clicking his teeth to the point where there are little chips on them. What do I do?!

It drives my partner and I nuts! And I'm scared because he's damaging his teeth.... he does it mostly when he gets excited when we're playing.How can I prevent him from doing it? Is there a bigger reason to why he does it?Edit: He doesn't really do it with me anymore because I tell him not to but he still does it with his dad because he has lots of fun with him.He does mostly do it when he's excited but he does it randomly from time to time. It's bad. via /r/Parenting http://ift.tt/2y1AkZB