Hello, most children recover from this as they grow older, If you suspect that the teeth grinding is related to stress or anxiety, do what you can to help your toddler relax. Work on establishing a calming bedtime routine, complete with a warm bath, relaxing music, bedtime stories, etc. This can do wonders to help relax your toddler right before she falls asleep. There could be come medical causes for this teeth grinding too like, nutritional deficiency or any sort of pain, consider visit pediatrician in that case.