Two people can show the same band of gum when they smile for completely different reasons. In one, gum still covers part of each tooth. In another, the upper lip simply lifts higher than most. Because the treatments for those causes have little in common, the first job is a diagnosis, not a procedure.
Four things a dentist checks
Dental papers use slightly different cut-offs for when gum display counts as excessive, usually a few millimetres of gum on show in a full, relaxed smile. In the end it is also a personal judgement: some people with a lot of gum on show like their smile, and others are bothered by less. When it does bother you, the assessment comes down to four questions.
Are the teeth partly covered by gum?
As adult teeth come through, the gum normally moves back up the crown during the teen years and settles near where the enamel meets the root. In some people that process stops short, so gum and sometimes bone sit lower on the tooth than usual. The teeth look short and square even though their full length is hidden underneath. This is called altered passive eruption, and a dentist can often confirm it by gently probing to find where the enamel ends beneath the gum.
Does the upper lip lift higher than average?
Some people have very active lip-lifting muscles, or a short upper lip, so a broad smile pulls the lip well above the gum line. The teeth and gums can be entirely normal. Watching a natural, unposed smile, or video of one, shows this best.
Has the upper jaw grown longer vertically?
When the upper jaw has developed more in height than usual, the teeth and gums sit lower in the face and more gum shows when the lips part. The lips may not close comfortably at rest. This is a skeletal pattern and usually needs an orthodontic and surgical opinion rather than gum treatment.
Have some teeth come down further than others?
Teeth that have erupted further than their neighbours bring gum and bone down with them. This often affects a few front teeth, sometimes alongside a deep bite, rather than the whole smile.
Matching the treatment to the cause
Gum covering the teeth is usually treated with gum reshaping. When only soft tissue needs removing, this is a gingivectomy, described in our article on gingivectomy and gum reshaping. When bone also sits too close to the enamel, a crown lengthening procedure removes a little bone as well, so the gum does not simply creep back.
An active upper lip can be managed temporarily with muscle-relaxing injections, which reduce how high the lip lifts. The effect wears off: a 2018 meta-analysis in Brazilian Oral Research (Chagas and colleagues) pooled three small studies and found gum display dropped clearly within two weeks, then began to creep back during the 12 weeks of follow-up, and noted that the evidence on how long the effect lasts is limited. For a longer-lasting change, a lip repositioning procedure limits how far the lip can rise; our article on lip repositioning surgery explains it.
Teeth that have come down too far can often be moved up with braces or aligners, sometimes with small temporary anchorage screws. A long upper jaw is the most involved cause to treat, and when the skeletal pattern is marked, the usual approach is orthodontics combined with jaw surgery under a specialist team.
Why many smiles need a combined plan
It is common to have more than one cause, such as gum covering the teeth together with a lip that lifts high. Treating only one of them may leave the smile only partly changed, which is a frequent reason people feel a first treatment "did not quite work". Planning the whole picture first tends to give a more predictable result than trying one option after another.
Once the gum line is corrected, the teeth themselves sometimes need attention too. Small changes to their shape can be made with tooth contouring, and broader changes may involve bonding, veneers or crowns. If whitening is part of the plan, it is usually done before any tooth-coloured restorations are matched, as our article on whitening veneers and crowns explains. Larger plans are covered in our smile makeover guide.
What patients ask about gummy smiles
Can braces fix a gummy smile?
Braces or aligners can help when certain teeth have come down too far or the bite is involved. They do little for a smile driven by an active lip or by gum covering the teeth.
Does gum reshaping hurt?
It is done with local anaesthetic, so the procedure should not be painful. The gums are usually tender for some days while they heal.
Will a gummy smile change with age?
Gum position and lip movement are usually fairly stable through adult life. Gum recession from other causes, such as gum disease or heavy brushing, can change how much gum shows over time.
Starting with an assessment
If you are self-conscious about how much gum shows when you smile, an assessment is the place to start, because it tells you which cause applies before you decide on anything. Lumi Dental offers a free cosmetic consultation to look at your smile and talk through the options, including referral where another practitioner is better placed to help.
This article is general information only and is not a substitute for an individual dental assessment.
