Gummy smile has been a challenge to treat properly especially when it is advanced Gummy smiles occur for a variety of reasons, most commonly a short upper lip, excessive gum tissue or small teeth, all of which are genetic. Anything over three to four millimeters of gum showing starts to look gummy.

Studies have been done with dentists, plastic surgeons, dermatologists and regular folk to assess smiles. Most everyone agreed that two millimeters or less of gum tissue showing was the level where most participants thought the smile looked normal.