When treating a gummy smile, the goal is to relax a hypertonic lip. Because of the muscles that run along and under the nose, when someone smiles, they show more gum than teeth.

You can never be sure how far the patient’s lip will fall when you relax it, so they must expose at least as much gum as the tooth. To be safe, the gum must be 10 to 11 meters long because if you relax your lips, you never know how far they will drop. For example, a person may have a front tooth that measures 10 or 11 millimeters in length.

A 10-millimeter tooth, for example, will cause the lip to drape below its incisal margins if the person has a four- or five-mm gummy smile with four or five millimeters of gum visible.

This means that the quantity of gum displayed on the tooth should be proportional to its length. It would be best if you did not touch that case unless you have a valid reason.
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