Damon braces are a type or brand of 'braces' that the orthodontist uses to accomplish their goals of aligning your teeth and correcting your bite. The Damon braces alone may or may not fix your 4mm overbite, but you wearing elastics that attach to the Damon braces will indeed be one way to aim to correct the 4mm overbite. So it will be a function of the Damon brand braces and your compliance to what the doctor prescribes you to wear that will address the 4mm overbite.
