How can I stop grinding my teeth when I sleep?

De-Stress. "bruxism", the compulsory grinding of teeth day or night, is most often the result of built up anxiety and muscle tension in the body. Anxiety is what we experience when we have unresolved conflicts occupying our subconscious mind, manifesting with nervous tension. Try to learn to de-stress by identifying your unresolved conflicts and then writing down solutions to them before going to sleep.
TMJ Expert. A difficult problem to treat. Work with a TMJ expert, He/she will try nightguard. Sometimes medications help.
See dentist. A mouthpiece may help you with clenching or may even cause you to clench more. The type of mouthpiece can often determine if it will improve your problems, but the mouthpiece alone may not be the answer. Do you wear the mouthpiece during the day and night. Grinding is what occurs at night, clenching occurs during the day.
Maybe sleep disorder. We now know that obstructive sleep apnea is one of the most common causes of nocturnal bruxism (grinding or clenching teeth during sleep). The idea that it is caused by bite misalignment has largely been discredited.