It is common for patients to present with what dental professionals would call a “gummy” smile. This appearance of excessive gingiva above the cervical of the maxillary anterior teeth in a full smile can have multiple causes, one of which is the diagnosis hypermobile lip. When we think about excessive gingival display, the first thing to remember is that not everyone finds this unattractive. Many of my patients show a significant amount of gingiva at a full smile and find it very pleasing esthetically. Commonly when there is more than 3-4mm of gingival display we and our patients will find this as an esthetic issue, but I remember to bring this conversation up gently so as not to offend someone who isn’t bothered by it.
As a starting point when considering a diagnosis of hypermobile lip we need to have a baseline for “normal” lip mobility. A study at UCLA showed an average lip mobility of 7-8mm between repose and a full smile. Given this information we can begin with a lips at rest photograph and make note of the lip position relative to the upper central incisors. Than with the patient in a full smile note the position of the upper lip. The difference between the two should be in the range of 6-9mm, or our patient has a greater than average mobility, ie a hypermobile lip. One caution is that simply knowing lip mobility doesn’t uncover the entire story, nor does it direct us to the possible array of treatments to correct the “gummy” smile. When diagnosing excessive gingival display I want to look at a number of diagnostic findings including:
- Is tooth size and proportion normal?
- Is the excessive i display anterior only or anterior and posterior?
- Is the incisal plane level with the occlusal plane?
- Are the facial proportions normal?
- Is there excessive lip mobility?
Putting all of these findings together is what will lead me to an appropriate treatment recommendation. If it is determined that treating the lip mobility makes sense to decrease the gingival display I suggest to my patients that we start with Botox. The injection of Botox will paralyze the muscles that elevate the upper lip. If the patient is happy with the results, they can than chose to have the Botox therapy continued or see a plastic surgeon to have a surgical correction.