Invisalign corrects the same dental problems as traditional metal braces; the only difference is that Invisalign trays are almost invisible to the naked eye, and can be removed at will.
Here are some problems that are commonly corrected with Invisalign:
Overcrowding – This occurs when there is too little space for the teeth to align normally in the mouth.  Overcrowding can cause tooth decay and increase the likelihood of gum disease.
Large gaps between teeth – This can sometimes occur because teeth are missing or because the jaw continues to grow abnormally.
Crossbite – This common dental problem occurs when one or multiple upper teeth bite inside the lower teeth.  As a consequence, uneven wear can lead to bone erosion and gum disease.
Overbite – This problem occurs when the upper teeth project further than, or completely cover, the lower teeth.  Eventually, jaw pain and TMJ may occur.
Underbite – This is the inverse of the overbite; the lower teeth project further than, or completely cover, the upper teeth.  Eventually, jaw pain and TMJ can occur.