Grinding of teeth especially while sleeping or Bruxism, in medical language can trigger off a lot of chronic ailments including; migraine, dental problems, anxiety and depression. As this is an involuntary act, caused due to sub conscious action and mostly occurring during sleep, is advisable to get rid of it permanently; especially in children.
The paranormal Indian remedy which I have given here can be tried if nothing else succeeds
Then pick up some of the Bael Leaves and Rice Grains and before going to bed hold them in your mouth for sometime. Then remove them [you can immerse it in flowing water the next day] and go to bed. It is said that with the blessings of Shiva, the grinding and clenching of teeth will come to an end.