Should you be concerned about it?
While the sound of grinding and clenching teeth can be irritating and disconcerting, it is quite harmless in most of the cases. In all probability, your child is going to grow out of the habit and there will be no physical damage to his teeth. If you are still concerned, you can take your toddler to a pediatric dentist who can have a look at his/her teeth and inspect for any wearing out signs or some other oral problems like fractures, cavities and pulp exposure.