Gummy Smile: Is It Your Gums, Your Teeth or Your Lip?

When you smile, how much gum shows? For some people the answer is "more than I would like". The teeth look short, or a band of gum shows above them. This is usually called a gummy smile, and it is common: a 2024 review in the journal Cureus cites a study that found it in about 7% of adults (Cureus).

The most important question is not how to fix it, but why it happens. "Gummy smile" describes what you see, not what causes it. The same look can come from the gums, the teeth, the upper lip or the jaw, and a treatment that suits one cause can do nothing for another.

How much gum is "too much"?

There is no strict rule, and taste plays a part. The same review notes that more than about 3 mm of gum showing in a smile is generally considered unattractive (Cureus). In practice, what matters most is whether it bothers you, and whether your teeth and gums are healthy.

The four places a gummy smile can come from

The review describes several causes, and many smiles have more than one.

The gums

In some adults, the gum never moved as far up the tooth as usual after the teeth came through, so part of each tooth stays covered. Dentists call this altered passive eruption. The teeth are a normal length; you simply cannot see all of them, so they look short and square. Gums can also grow over the teeth: Cleveland Clinic lists certain medicines and braces or other orthodontic appliances among the reasons (Cleveland Clinic). Swollen, inflamed gums can look larger too.

The teeth

Teeth that are short because they are worn down, or teeth that have moved further down than usual, change how much gum shows around them.

The upper lip

Sometimes the gums and teeth are normal, and it is the lip that reveals more of them. A lip that lifts higher than average when you smile (a hypermobile upper lip), or a short upper lip, has this effect. The review names the mobile lip and altered passive eruption as the two most common causes (Cureus).

The jaw

In some people, the upper jaw has grown longer vertically than usual. Dentists call this vertical maxillary excess. The lower half of the face can look longer, and the gum shows because of the bone, not the gum itself.

Why the cause decides the treatment

The review is clear that each cause needs a different treatment, and that people with a gummy smile should be evaluated carefully before a plan is made (Cureus). Broadly:

• Gum covering part of the tooth. The gum line is reshaped to uncover the full tooth. This is crown lengthening, sometimes called gum contouring. Where needed, a small amount of the bone underneath is reshaped too, so the gum settles in its new position.
• Short or worn teeth. Veneers or crowns can restore their length, often planned together with gum reshaping, so that teeth and gums are in proportion (Dental Crown vs Veneer).
• Teeth that have moved down. Orthodontic treatment may be part of the plan.
• The lip. Gum surgery does not change how a lip moves. Treatments aimed at the lip, such as lip repositioning surgery, are a different field, and the review discusses them in detail. If your smile is mainly about the lip, a dentist should tell you so before suggesting any work on your gums.
• The jaw. The review describes jaw surgery (orthognathic surgery) as the main treatment for a long upper jaw. It is planned with specialists, and it is a much bigger decision than gum reshaping.

When there is more than one cause, the treatments can be combined.

How the cause is found

A gummy smile is diagnosed by looking at the whole smile, not only the gums. At a consultation, your dentist looks at:

• How much gum shows when your lips are relaxed, and when you smile fully
• The length and width of each tooth: a tooth that looks short and square may be partly covered
• Where the gum sits on the tooth, and where the bone sits beneath it, which the examination and X-rays show
• How far your upper lip lifts when you smile
• Whether the gums are healthy

At Mineers, this is part of the smile analysis. We photograph your face and smile, and measure the smile line on screen, so you can see how much tooth and how much gum shows, and what would change it (What Is Digital Smile Design?).

If it is the gums: what crown lengthening involves

When the cause is gum covering the teeth, crown lengthening at Mineers is done under local anaesthetic, with laser and micro-surgical techniques that remove only the tissue needed. The procedure takes about 30 to 60 minutes. The gum heals over one to two weeks, and settles into its new shape over six to eight weeks. Some tenderness at first is normal.

The same technique is used to even out the gum line before veneers. When both are planned, the new gum line is designed together with the new smile, so the two fit. Our crown lengthening page shows each step.

A quick check in the mirror

Smile fully in the mirror, or ask someone to take a photo:

• Do your teeth look short or square, even though they are not worn? The gum may be covering part of them.
• Do your teeth look a normal length, while your lip lifts high above them? The lip may be the main factor.
• Are your gums red, puffy or bleeding? Have your gum health checked first (Bleeding Gums When You Brush).

This is not a diagnosis, but it is a useful thing to mention at a consultation. You can also send us photos first; How to Send a Photo of Your Smile shows which ones help.

Would you like to know why your gums show when you smile? Book a private consultation or message us on WhatsApp, +961 3 757 127.

This article is general information, not a diagnosis. Treatment plans and results vary from person to person.