Despite what some people think, orthodontic appliances do not cause cavities or decalcifications (white marks on teeth) and are nearly always preventable. These white marks are caused by the build up of plaque on the tooth enamel that occurs due to inadequate oral hygiene.
Basically, decalcification is the loss of calcium from the tooth enamel. This is the first stage of a cavity and can occur in anyone, with braces or not. These marks are considered permanent without treatment! If left untreated, these marks can progress into cavities.
In most instances, Dr. Miller can use Calcium Hydroxide to reduce the appearance of decalcification marks.

Even better than reversing the effects of decalcification is not getting it in the first place. Remember, you can prevent decalcification with great oral hygiene!