A gummy smile is when an unusually large amount of gum tissue shows above your upper teeth when you smile. The clinical term is “excessive gingival display.” Showing 1 to 2 millimeters of gum when you smile is normal. Most dental professionals consider anything over 3 to 4 millimeters excessive, and a gum-to-lip distance of 4 millimeters or more is generally where a smile starts to look disproportionate.
Whether a gummy smile bothers you is entirely personal. It’s not a health problem on its own, but it can affect how confident you feel about your smile. Understanding what causes it helps clarify what, if anything, can be done about it.
What Causes a Gummy Smile
There’s no single cause. A gummy smile can come from the way your teeth grew in, the size of your jaw, the length of your lip, or how much your lip moves when you smile. Sometimes it’s a combination of several factors. The causes generally fall into three categories: your gums and teeth, your jawbone, and your lip.
Gum and Tooth Issues
One of the most overlooked causes is something called altered passive eruption. When your adult teeth come in, there are two phases. First the tooth pushes through the gum (active eruption), then the gum tissue is supposed to gradually pull back and settle at the base of the tooth’s crown (passive eruption). In some people, that second phase never fully completes. The gum stays higher on the tooth, covering more enamel than it should. This makes the teeth look short and the gums look oversized, even though the teeth underneath are normal length.
Gum overgrowth from other causes, like certain medications or chronic inflammation, can also increase the amount of visible gum tissue.
Jawbone Position
If the upper jaw grew longer than average vertically, the entire row of upper teeth and gums sits lower on your face. Even with perfectly normal teeth and gum proportions, the extra bone length pushes everything downward, so more gum shows when your lip rises. This is called vertical maxillary excess, and it’s the most structurally significant cause because it involves the bone itself rather than soft tissue.
Lip Shape and Movement
Some people have a short upper lip that simply doesn’t cover as much of the gum line at rest or while smiling. Others have what’s called a hyperactive upper lip: the muscles that pull the lip upward during a smile are stronger or more active than average, lifting the lip higher than typical. In these cases the teeth, gums, and jaw may all be perfectly proportioned, but the lip reveals more than usual.
Teeth that have drifted downward over time (over-eruption) or a bite where the upper front teeth protrude forward can also contribute by pushing the gum line into a more visible position.
How It’s Diagnosed
A dentist, periodontist, or orthodontist will typically measure the amount of gum visible during a full, natural smile. They’ll also assess your tooth proportions, gum thickness, jawbone position, lip length, and lip mobility. The goal is to figure out which specific factor, or combination of factors, is driving the excess display. This matters because the treatment depends entirely on the underlying cause.
For example, if your teeth appear short because gum tissue never receded properly, the fix is completely different from a case where the upper jaw is too long vertically. Getting the diagnosis right is what separates a good outcome from a disappointing one.
Non-Surgical Treatment Options
For gummy smiles caused by a hyperactive upper lip, injections of botulinum toxin (commonly known by the brand name Botox) can temporarily weaken the muscles that pull the lip too high. The injections are placed near the base of the nose and along the crease between the cheek and lip, targeting the specific muscles responsible. The effect typically lasts a few months before the treatment needs to be repeated, making it a low-commitment option for people who want to try something before considering surgery.
Orthodontic treatment can help when the gummy smile is related to how the teeth are positioned. Small anchor screws placed temporarily in the jawbone allow orthodontists to push the upper front teeth upward (intrusion), which brings the gum line with them. Research shows these devices are effective at reducing gum display in patients with a deep bite, and they’re considered a conservative alternative to jaw surgery. Treatment with these anchors typically takes around five months.
Surgical Treatment Options
Gum Contouring and Crown Lengthening
When the issue is too much gum tissue covering normal-sized teeth, a procedure to remove the excess tissue can make a dramatic difference. There are two main approaches. A gingivectomy removes only the soft gum tissue, typically using a scalpel or laser. It’s a relatively quick in-office procedure with a recovery time of a few days to a few weeks.
Crown lengthening goes a step further. The surgeon lifts the gum tissue, trims the excess, and reshapes the underlying bone to create a proportional, lasting result. Because it involves bone, it’s more involved. The procedure takes about an hour under local anesthesia, and full healing (enough for any follow-up cosmetic work like veneers) can take up to six months. The results are permanent, which is the main advantage over a gingivectomy alone.
Lip Repositioning
For cases driven by a hyperactive or short upper lip, lip repositioning surgery limits how high the lip can travel when you smile. The surgeon removes a strip of tissue from inside the upper lip and reattaches it in a position that restricts upward movement. This is a less invasive alternative to jaw surgery and works well when the teeth and bone are otherwise normal.
Jaw Surgery
When vertical maxillary excess is the primary cause, meaning the upper jawbone itself is too long, orthognathic (jaw) surgery may be the only way to achieve a significant correction. The surgeon repositions the upper jaw to reduce its vertical height. This is the most involved option, reserved for cases where the skeletal structure is the root of the problem and less invasive approaches won’t produce meaningful results.
How Treatment Is Matched to the Cause
The most important thing to understand about gummy smile treatment is that there’s no one-size-fits-all fix. A person whose gums never properly receded from their teeth needs crown lengthening, not Botox. Someone with a hyperactive lip and perfectly normal teeth would get no benefit from gum surgery. And a patient with a vertically long jaw won’t see lasting results from any of the softer interventions.
Many people have more than one contributing factor. You might have slightly short teeth from incomplete gum recession combined with a lip that lifts a bit too high. In these cases, treatment often involves addressing both issues, sometimes in stages. A thorough evaluation that identifies every contributing factor is the most important first step toward a result that actually looks and feels right.