### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
My husband used to grind his teeth in the nights. We went to a dentis and told regrding this. He said this can cause his teeth to be crooked if left like this. He prescribed some thing called Dental night guards. What are thse ? Is this useful for teeth grinding ?

### output:

Hello and thank you for your questions. Crooked teeth that don't close together like puzzle pieces may result in the body wanted to get a more balanced bite.  This normally occurs in your sleep where you brain says, this doesn't feel just right, I need to make things better.  So your teeth start to grind to try and smooth down the bite to a more balanced fit.  This does not necessarily help your teeth, this can cause teeth to loosen if combined with poor oral hygiene, tooth sensitivity, sore jaw muscles, neck muscles and lower back muscles, pressure headaches, pain in the jaw joints, clicking of the jaw etc. "b" A night guard is a device that is like a hard or soft retainer that seats on your teeth and has a nice balanced surface for your opposing teeth to rest on.  It's like a smooth ice skating rink for your teeth.  This device helps improve the grinding but may not stop it completely.  The good news is that your teeth will be grinding on a plastic device rather than your teeth, and it will reduce the risk of losing tooth structure.  "B" These devices are great for grinding.  I prefer hard night guards because the firmness helps prevent them from breaking down and they don't flex like soft night guards which in your sleep may be perceived as food and induce more grinding.  I personally use a night guard and found that it has improved my bruise condition greatly.  They are well worth the money. Best Regards and good health 