Gummy Smile: What Causes It and What Are the Treatment Options?Gummy Smile: What Causes It and What Are the Treatment Options? 

Seeing a little gum above the upper teeth in a broad smile is entirely normal. When the amount of visible gum passes a certain point, some people start to see it as a cosmetic concern. In the dental literature, more than roughly 3–4 mm of gum on show is often described as “excessive”, but this is not a disease definition, and how it is perceived varies from person to person and even between cultures. Studies report it more often in women.

A gummy smile is a description, not a diagnosis. The same appearance can come from very different causes, and the right treatment depends entirely on which one applies. The first step is therefore to work out whether the gum, the teeth, the lip or the underlying jaw structure is responsible. Gum aesthetics is one part of a wider smile plan; the overall approach is explained on the smile design page.

These are the main causes of a gummy smile; more than one can be present in the same person:

• Altered passive eruption: After the teeth come through, the gum is expected to move some way back up the tooth. If this process is incomplete, the gum keeps covering part of the crown and the teeth look short and square.
• Short clinical crowns: Wear, fractures or clenching can shorten the teeth, so the proportion of visible gum increases.
• Hypermobile upper lip: The upper lip lifts higher than average when smiling. Even with normal teeth and gums, more gum is on show.
• Short upper lip: When the resting length of the lip is short, more of the teeth and gum are exposed.
• Vertical maxillary excess: A skeletal cause in which the upper jaw has grown more than usual in the vertical direction; the lower face may look long and the lips may only close with effort at rest.
• Over-eruption of the upper front teeth: The front teeth have moved further down than usual, often together with a deep bite; this needs an orthodontic assessment.
• Gum enlargement: Gum inflammation, poor oral hygiene, the period of orthodontic treatment or certain medicines (for example some blood pressure, epilepsy and immunosuppressant drugs) can make the gum grow.

Diagnosis starts by looking at the face and smile as a whole. Photographs and short video clips help show how the lip moves during speech and laughter. The assessment mainly looks at:

• Smile line: where the upper lip sits relative to the teeth and gum in a full smile (low, average or high smile line)
• Lip length and mobility: how long the lip is at rest and how far it lifts when smiling
• Tooth display at rest: how much of the front teeth shows with the lips slightly apart
• Width-to-length ratio of the crowns: if the upper front teeth look squarer than expected, the gum may be covering part of them
• Gingival zeniths: the highest point of the gum margin on each tooth, and the harmony and symmetry between neighbouring teeth
• Gum and bone relationship: periodontal probing and measurement of the bone level, with X-rays where needed

These measurements show how far the bone sits from the junction between enamel and root (the cemento-enamel junction) and how much gum can be safely reshaped. With digital photo analysis and an intraoral scan, the planned change can be modelled in advance; these tools are described on the digital dentistry page.

This is the distinction that sets the direction of the treatment plan. Gum- or tooth-related cases can usually be corrected with procedures inside the mouth, whereas lip-related or skeletal cases need input from other specialties.

Gingivectomy, often called gum contouring or a gum lift, reshapes gum tissue that covers too much of the tooth, under local anaesthetic. If the bone sits at a suitable distance from the cemento-enamel junction and there is enough attached gum, it may be sufficient on its own. Healing usually takes a few weeks, and some sensitivity is common in the first days.

Crown lengthening is periodontal surgery in which the underlying bone is carefully reshaped as well as the gum. If the bone is too close to the cemento-enamel junction and only the gum is trimmed, the gum tends to creep back towards its old position, and chronic inflammation can develop. That is why the natural distance between bone and gum margin (the supracrestal tissue attachment, formerly called the biologic width) needs to be preserved. In the aesthetic zone, a wait of a few months is usual before final crowns or veneers, so that the gum level can settle.

Where teeth have become short through wear or have an irregular shape, their length and proportions can be restored with veneers or crowns after the gum procedure. The amount of tooth preparation and the choice of material then matter a great deal: the Turkey teeth guide explains how much tooth is reduced for veneers and crowns, and composite vs porcelain veneers compares the two main veneer options.

For a gummy smile caused by a hypermobile upper lip, botulinum toxin injected into the muscles that lift the lip is a method described in the literature. Its effect is temporary: it usually fades after a few months and has to be repeated to be maintained. It does not correct a gummy smile that comes from the gum or the teeth, and its effect is limited where the cause is skeletal.

This treatment lies outside the scope of prosthodontics and is mentioned here for information only, not as a recommendation. Suitability, possible side effects and who may carry it out should be discussed with an appropriately qualified clinician. Lip repositioning surgery, which aims to limit how far the lip lifts, has also been described as an option; however, partial relapse over time has been reported.

1. 1

   Examination and smile analysis

   An oral examination, photographs and video are used to assess lip movement, the smile line and tooth proportions.

2. 2

   Periodontal measurements and imaging

   Pocket depths, the amount of attached gum and the bone level are measured, with X-rays where needed. Any gum inflammation is treated first.

3. 3

   Identifying the cause and a team decision

   The team establishes whether the gum, the teeth, the lip or the skeleton is responsible. Orthodontic or surgical opinions are obtained where needed.

4. 4

   Digital planning and a trial smile

   The planned gum level and tooth proportions are modelled digitally; in suitable cases they can be previewed in the mouth with a temporary mock-up.

5. 5

   Treatment and healing

   Gingivectomy or crown lengthening is carried out under local anaesthetic. Time is then allowed for the gum level to settle.

6. 6

   Restorations if needed, and follow-up

   If tooth shape needs completing, veneers or crowns are made. Gum health is monitored with regular check-ups.

Like any clinical procedure, gum treatment and any restorations that follow carry outcomes that vary between individuals, as well as possible risks; common questions are answered on the FAQ page. For day-to-day care after treatment, see veneer and crown aftercare. Appointment details are on the contact page, and consultations are available in English.