What you're describing is Bruxism, perhaps in the early stages. Often the origin of tooth grinding is a period of anger / stress / anxiety where no external physical action was possible at the time. Over time the internalised anger may be processed by the mind but the tooth grinding behaviour can sometimes remain.

Hypnotherapy / EMDR and timeline therapy are very effective with most cases of Bruxism. Generally only a few sessions are required - sometimes only one.

http://www.changingstates.co.uk/issues/bruxism.html

To start the process of removing this symptom from your life just let me know your availability and we can book an appointment.