1) Get a night guard, the hard plastic type
2) Exercise with him, saying "Lips together, teeth apart" before he goes to bed
3) Try giving him some sort of medication to reduce his tension
Hope this helps,
Jossi Stokes, DDS
If your son has baby teeth or mixed dentition, there's not much you can do for grinding of the teeth.
Your son grinding his teeth can be related to several issues. It could be some sleep issue, teeth position or is during period of permanent teeth growth. We recommend an oral appliance that will help with grinding and at the same time will resolve any sleep related issues and teeth position.
Lisa Wu, DMD