Small injections of Botulinum toxin are placed into the Masseter muscle to relieve the habitual action of grinding and clenching, by relaxing the muscle. 

It takes up to 14 days for the effects to take effect, once placed into the muscle.

Whilst it is a very popular treatment, it is a temporary action and similar to other botulinum toxin injections, lasting on average 3-4 months (sometimes longer) depending on the individual muscle strength.