Brown spots on the teeth can occur for several reasons ... When the tooth is hit it can become discolored, appearing gray or brown, either immediately or progressively over time.

The development of white spots on the teeth—clinically called "decalcification"—can be distressing. These deposits are common, arising due to plaque and tartar build-up, insufficient enamel ...

White spots on your teeth can be due to a number of things from malnutrition to poor oral hygiene. Once those white spots turn up it's hard to get rid of them but you can reduce their appearance.