I want to ask you to PLEASE find a dentist that will build a mouth piece for your child to get this behavior stopped as soon as possible. I too starting grinding my teeth as a child. They did not make mouth pieces then. The dentist assured my parents that I would grow out of it. I never did. There were times when I would wake up with bits of teeth in my mouth where I had ground(?) my teeth so hard. I would wake up some mornings with my ear/ears hurting from nothing more than grinding my teeth. That still happens on occasion. If not corrected, it can become a lifelong problem and result in some VERY costly dental bills. (My latest estimate is over $3000. Now that is from grinding my teeth as well as Acid Reflux and the acid eating away at my teeth, but still you can see where it can add up.) Not all dentists will go ahead and make the mouth piece, but I urge you to find one that will. Most children find the mouthpiece uncomfortable and will do anything not to have to where it at night. I can tell you that it does take a concentrated effort to not grind one's teeth. When my son started it as a young toddler, I started keeping him in bed with me and would wake up when I heard him doing it and would wake him up and have him stop grinding his teeth. It took a long time (over a year), but he no longer grinds his teeth. Sure wish I could have found a dentist to make a mouth piece for him rather than have him bruising me from head to toe sleeping with me. hHwever, we did get it accomplished, but not without some dental bills for four fillings where he ground the tops of his teeth off.
Good luck to you. And if you find a dentist that will make a mouth piece, please fill me in. I have another toddler now that hasn't started it, but would like to be prepared should she start it.
Oh! It seems, to me anyway, that the harder one chews their food, the more likely they are to grind. One dentist even told me that I need to quit chewing so hard and so does my son. So, I guess you can take that for what it's worth. I know that my son and I both chew pretty hard and firm. so, maybe there is something to that.
Again, good luck to you.