as teeth grinding/ clenching is called, can be helped by taking a sinemet CR at night. It is often a trade off between teeth grinding and nightmares, but if you use a muscle relaxant sleep aid along with it, you can often notice a real improvement in symptoms. I have always been a grinder, even before a PD dx. Lately if i forget all the ingredients in my nighttime "cocktail", I wake up with pain and bleeding from my tongue being between my teeth getting bitten upon. I didn't take well to nighttime "retainers", i just can't stand the feel of anything in my mouth at night. Go to a dentist, if grinding is happening, it will be obvious to them, and a good dentist will recommend the cheap products instead of the expensive "made for you" variety that are usually totally unnecessary. The sports industry has developed a product that forms to your teeth under pressure and is disposable as it gets older. Under mediation is suspect in your case because you have noticed increasing daytime PD symptoms