Grinding while awake is a learned habit and as ErinBear suggested can be unlearned.

Bruxism is a neuromusclar response of chewing while sleeping. It's not something that can be unlearned. Mouthguards are an option for treating Bruxism. If your insurance covers Botox injections they have been shown to be highly effective for weakening the jaw muscles while not impairing your ability to eat or facial expressions.

Many people associated botox injections with cosmetic surgery and that is true. However the original medical purpose of botox is for things like Bruxism.