Gummy smile: when toxin solves it and when it doesn't

A gummy smile — when a band of gum shows above the teeth on smiling — has become one of the most heavily promoted uses of botulinum toxin.

The problem is that it has four different causes, and toxin treats only one of them well. Treating without knowing which one is yours produces one of two outcomes: an insufficient result, or a result that changes the smile in ways you did not want.

This is a subject where the diagnosis is dental before it is aesthetic.

The four causes of a gummy smile

1. Muscle hyperactivity

The upper lip rises higher than expected on smiling, because the elevator muscles are very active.

This is the only one toxin treats well. Partially relaxing those muscles reduces the lift of the lip, and less gum shows.

2. Excess gum tissue

The gum covers more of the tooth crown than it should, leaving the teeth looking short. The lip may be rising normally — what there is too much of is gum.

Toxin does not solve this. The approach is periodontal, with crown lengthening surgery.

3. Skeletal difference

Vertical maxillary excess: the bone is taller than standard, and that exposes more gum regardless of the lip and the gum tissue.

Toxin does not solve this. The approach is orthodontic or orthognathic, depending on the degree.

4. A short upper lip

The lip is short at rest, and even a normal amount of lift exposes gum.

Toxin partially solves this, within a narrow limit — and it is the scenario where overtreatment happens most.

And often it is more than one

Mixed cases are common, and that is what makes the diagnosis indispensable. Treating the muscular component of a predominantly skeletal case delivers a small improvement that disappoints.

How yours is identified

The assessment involves measuring and observing specific things:

• How much gum shows on smiling, in millimetres
• The length of the upper lip at rest
• How far the lip lifts between rest and smile
• The proportions of the tooth crowns — short teeth point to excess gum
• The maxillomandibular relationship, which points to a skeletal component

Note that three of those are a dental examination. Assessing a gummy smile by looking only at how the lip moves, without examining teeth and gums, is assessing a quarter of the problem.

It is one of the points where a background in dentistry is not adjacent to the subject — it is central to it.

How toxin treats a gummy smile

It partially relaxes the elevator muscles of the upper lip, reducing the height the lip reaches on smiling.

The margin is extremely narrow. Unlike the glabella, where the dose has some room, here a few points and a small dose separate an appropriate result from an altered smile.

Possible unwanted effects:

• An asymmetric smile, when the two sides respond differently
• A heavy or "drooping" upper lip, with difficulty lifting it
• Changes in speech on some sounds, usually slight and temporary
• Difficulty whistling or using a straw

All temporary, and all linked to a dose above what was needed.

Duration

Three to four months, one of the shortest in the face. The musculature is delicate, the dose is necessarily low, and the area is in constant movement.

That means more frequent maintenance than other indications — which needs to be part of the calculation before starting.

When we advise against it

• Without a diagnosis of the cause. This is the most important refusal on this subject.
• When the predominant component is gum tissue or skeletal. Toxin will deliver little, and the correct treatment is another one — periodontal, orthodontic or orthognathic. We refer out.
• A high dose to "fix it for good". That is the direct route to an altered smile.
• A touch-up before day fifteen. Here the rule matters even more, because of the narrow margin.
• In people whose work depends on their speech — broadcasters, singers, teachers — without explicitly discussing the risk of temporary change.
• Before an important event. Two weeks is the minimum; three is comfortable.

Frequently asked questions

Does Botox fix a gummy smile?

It does when the cause is muscle hyperactivity. For the gum-tissue and skeletal causes, no — and in those cases the right treatment is a different one.

How long does it last?

Three to four months, one of the shortest durations in the face.

Can it change my smile?

It can, if the dose is above what was needed. This is an area with a narrow margin, and the correct approach is to start conservative.

How do I know which cause is mine?

Through an examination that includes the mouth: the proportions of the tooth crowns, the length of the lip, the lift on smiling and the maxillomandibular relationship.

Is there a permanent solution?

It depends on the cause. Excess gum tissue has a definitive surgical correction; a skeletal difference has an orthodontic or orthognathic correction. The muscular component, treated with toxin, is temporary by nature.