- Try to select a kit that allows some customization of the mouthpiece. Some kits come with a mouthpiece that can be molded to some degree. These are better than others that come with a standard mouthpiece.
- Try to gain the opinion of others who may have already tried the kit you are considering.
- If at any time you experience a prolonged change in the color of your gums or an increased tooth sensitivity to hot or cold foods and beverages, stop wearing the mouthpiece and see your dentist immediately.
Source : WebMD Medical Reference
