One look, four different problems

A gummy smile means more gum shows above the upper teeth than you want when you smile. The usual working definition is more than about two or three millimetres, though that is a convention and not a diagnosis. What matters is whether it bothers you.

What almost nobody is told before they start researching treatments is that four separate things produce it, and that they are handled by four different sets of hands.

1. The lip muscles pull too hard

The muscles that raise the upper lip can be strong or efficient enough that the lip simply travels further than average. The lip is a normal length, the jaw is a normal height, the teeth are a normal size. The lip is just going too far up.

2. The upper lip is short

Here the lip has less vertical height to begin with, so a perfectly ordinary amount of movement uncovers gum. This one is often visible at rest, not only when smiling, and it frequently runs in families.

3. The upper jaw is vertically long

This is a skeletal proportion rather than a soft tissue one. The upper jaw sits lower than average, which carries the teeth and gum down with it. No amount of work on the lip changes where the bone is.

4. The gum never finished receding

In adolescence the gum migrates off the surface of the teeth as they finish erupting. When that process stops early, the teeth are a normal size but look short, because part of each one is still covered. The gum is not excessive so much as still in the wrong place.

More than one of these is often present at once, which is the other reason a single treatment can produce a partial result and leave everyone puzzled.

Working out which one is yours

You can narrow it down considerably with a mirror and a photograph.

Smile fully, the way you would at someone you are pleased to see. A posed smile in a mirror underdoes it, so a candid photograph taken by someone else is more honest than anything you can produce deliberately.

  1. Look at your lip at rest. If the gap between the base of your nose and the top of your lip already looks short when your face is relaxed, a short lip is likely part of it.
  2. Watch how far the lip travels between rest and a full smile. A lip that moves a long way and disappears into a thin line points at muscle activity.
  3. Look at the teeth themselves. If they look short and squarish rather than rectangular, the gum may still be sitting over part of them, which is the fourth cause and is a dental question.

None of this substitutes for an examination, where lip length, lip mobility, tooth proportion and the vertical position of the jaw are measured rather than estimated. It does tell you which conversation you are having, and with whom.

What treats what

Muscle activity

Small, precisely placed doses of a neuromodulator reduce how far the lip elevators can pull. This is the treatment most people have heard of, and it works well for this cause specifically. The doses are small and placement matters a great deal, because too much product, or product slightly off target, produces an asymmetric or oddly flat smile that lasts as long as the treatment does. The effect wears off and needs repeating. Our Botox article covers how that assessment is made.

A short upper lip

A lip lift shortens the distance between the nose and the lip, which lowers the lip over the teeth. It is a surgical procedure with a scar placed at the base of the nose. It changes the resting appearance as well as the smile, which is a point in its favour for the right person and a reason for caution in the wrong one.

Filler in the upper lip can add a small amount of visible height and take the edge off a mild case. Restraint is the whole game here. Too much volume everts the lip and can draw more attention to the gum line, not less.

A long upper jaw

This is corrected by an oral and maxillofacial surgeon repositioning the upper jaw, usually with orthodontic preparation on either side of it. It is real surgery with a real recovery, and it is the right answer when the cause is skeletal. It is not something to drift into, and it is not something a lip treatment approximates.

Gum that never receded

A periodontist addresses this, commonly with crown lengthening, which reshapes the gum and sometimes the bone underneath to expose more of each tooth. It is a dental procedure. Someone whose gummy smile is entirely this can spend a lot of time and money in a plastic surgeon's office achieving very little.

Why the assessment comes first

Two of these four causes are not treated by a plastic surgeon. Saying so at consultation costs nothing and saves a patient a great deal, and it is the reason the examination matters more here than in most cosmetic complaints.

The pattern to avoid is the one where somebody with a short lip and a normal amount of muscle activity is treated repeatedly with injections, gets a small improvement each time that fades within months, and concludes that nothing works. Something does work. It was a different cause.

Find out which one it is

The examination that separates the four causes is quick, and it decides whether the answer is an injection, an operation, or a referral to someone else.

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The usual working definition is more than about two to three millimetres of gum showing above the upper teeth on a full, unforced smile. That figure is a convention rather than a rule, and it matters much less than whether it bothers you. Plenty of people show a few millimetres of gum and read as warm and open, which is why this is a preference rather than a defect, and why the first question at consultation is what you actually dislike when you look at a photograph of yourself.
Four separate things, and they are treated by different people. The muscles that raise the upper lip can be unusually strong or unusually efficient, so the lip travels further than average. The upper lip itself can be vertically short, so even a normal amount of movement exposes gum. The upper jaw can be vertically long, which is a skeletal proportion rather than a soft tissue one. And the gum may never have finished receding off the teeth during adolescence, so the teeth look short and the gum looks abundant. More than one can be present at once.
It reliably helps one of the four causes, the hyperactive lip elevator muscles, by reducing how far the lip travels upward. Small doses are used and placement is precise, because too much or slightly misplaced product produces an asymmetric or flattened smile for as long as it lasts. It does nothing for a short upper lip, nothing for a long upper jaw, and nothing for gum that never receded, which is why an honest assessment of the cause comes before any injection. The effect is temporary and needs repeating.
It depends entirely on the cause. A short upper lip can be addressed with a lip lift, which shortens the distance between the nose and the top of the lip. Gum that never receded is treated by a periodontist, usually with crown lengthening, and it is a dental procedure rather than a plastic surgical one. A vertically long upper jaw is corrected by an oral and maxillofacial surgeon repositioning the jaw, which is real surgery with orthodontic preparation. Muscle related cases often need nothing surgical at all.
Filler placed in the upper lip can add a little height to the visible pink and slightly reduce how much gum shows, and it is a reasonable and reversible thing to try in mild cases. It can also make the situation look worse if too much volume is added, because a heavier lip that everts can draw more attention to the gum line rather than less. The amount that helps is small, and this is one of the places where restraint separates a good result from an obvious one.

Related reading: lip lift for the short upper lip, Botox for the muscular cause, and lip augmentation for what filler can and cannot do around the mouth.