What is Excessive Gingival Display?
Having a bit of your gums show when you smile can give you a youthful appearance and is considered attractive. It’s normal to see about 1 to 2 millimeters of your gums when you smile. But, there can be a situation where too much of the gum shows while smiling, which is often referred to as a “gummy smile”. In some severe cases, too much gum may even be visible when the lips are at rest or not smiling.
The key to managing a gummy smile is to find out the reason behind it, as this will guide the treatment plan and help predict the outcomes. A variety of factors can cause a gummy smile. These may include a short or excessively movable upper lip, modified gum eruption, an overgrown upper jaw (also known as vertical maxillary excess or VME), over-eruption of the teeth in the upper jaw, and overgrowth of the gums. However, an overgrown upper jaw is one of the most common causes.
To diagnose a gummy smile, doctors often conduct detailed examinations that include analyzing the front and sides of your face, checking the lip line as well as the distance and display of teeth between the lips when at rest, and a thorough examination of the gums. X-rays of the mouth and a special technique called cephalometric analysis may also be required, with the latter being particularly used for diagnosing overgrown upper jaws.
What Causes Excessive Gingival Display?
A gummy smile – where more of your gum is visible when you smile – can be caused by many things, and sometimes more than one cause can apply at once. What’s causing the gummy smile affects how it can be treated.
The causes can include:
- A short upper lip
- An upper lip that moves a lot
- Changes in how your gum moves away from your teeth as they grow in
- Excessive gum growth
- Overgrowth of the upper jawbone
- Teeth moving out of their normal position
Vertical Maxillary Excess (VME) refers to an overly grown upper jawbone, which makes the lower part of the face look long. This is one of the most common causes of gummy smiles. You would need an x-ray scan of your face to confirm this diagnosis. This condition often results in your gum showing more when you smile because your teeth sit lower than they should. One key sign of this condition is when your lower lip covers the edges of your upper canine and premolar teeth.
Another cause, Altered Passive Eruption, is about how teeth grow. Teeth grow in two phases – an active phase when they reach their final position, and a passive phase when your gum moves down to expose the crown of the tooth (exposed part). If the gum does not move down enough, teeth can look short and square. It can be a challenge to diagnose this but looking at how the lips move and where it falls on the tooth can provide clues. Normally, the lip movement ranges between 6-8mm but if the lip moves up to 10mm from rest, it is an indication for this condition.
Anterior dentoalveolar extrusion refers to front teeth moving out of their normal position, which could lead to more of your gums showing when you smile. Possible causes of this include too much wear on the tooth or a deep bite alignment issue.
Risk Factors and Frequency for Excessive Gingival Display
About 10% of people between the ages of 20 and 30 show excessive gum display, a condition more common in women. However, this condition becomes less common as people age because the upper and lower lips drop, lowering the exposure of the gums and top front teeth.
Signs and Symptoms of Excessive Gingival Display
Pleasant smiles typically display specific characteristics. These include showing at least the second premolars, little upper gums visible, no gum recession along with visibly healthy inner parts of the gums between teeth. Other features are a lower lip line that mirrors the upper teeth’s cutting edge and similar size and shape between the front and back teeth. Also, teeth should be in the right shape, located appropriately, have a good color, and the right shade.
In dental aesthetics, a gummy smile is defined differently by various authors. Some consider a gummy smile as one showing more than 3 to 4 mm of gum tissue when a person smiles. Others view a gum exposure of more than 2 mm as excessive. Generally, dentists tend to regard a gum to lip distance of 4 mm or more during a smile as “unattractive”.
The next step after recognizing that a patient shows too much gum when they smile is to determine why. The causes of excessive gingival display can vary. The following is organized according to the affected tissue:
- Lips: Short lip, Hypermobile lip
- Teeth: Dentoalveolar extrusion, Altered passive eruption
- Maxillary bone: Vertical maxillary excess (VME)
- Gingiva: Gingival hyperplasia
Testing for Excessive Gingival Display
If you’re going to the doctor because of a “gummy smile”, they will take into account your medical history. For instance, your age helps to determine the development stage of your teeth, which can indicate if the gums have grown over them, a condition called “altered passive eruption”. Additionally, medications you might be taking for seizures, high blood pressure, or following an organ transplant, can sometimes cause an overgrowth of the gums.
The doctor will also look at your face from different angles to check for any anomalies or an excessive upper jaw growth, a condition known as vertical maxillary excess. More often than not, people with this condition have a particular arrangement of their skull bones which causes their lower jaw to be pushed back slightly.
The doctor will also examine your lips. If the lips aren’t covering the gums adequately when at rest, it can lead to a gummy smile. The doctor will measure the length of your upper lip, the average length for young adults is between 20 to 24 mm, but it can increase with age. If it’s less than 20 mm, it’s considered a short lip, which could lead to a gummy smile.
Additionally, some people have what’s known as a hypermobile or hyperactive lip. This is when the muscles that lift the upper lip work too well, causing more of the teeth and gums to be exposed when smiling.
The doctor will check how much of the upper front teeth are visible when your mouth is at rest. Typically, about 3-4 mm should be visible for young women, and 2 mm for young men; this amount decreases as we age.
They will also measure the gap between your lips when your mouth is at rest. If the distance is more than 4 mm, it could be due to short lips, extrusion (outward shift) of a tooth or teeth, or excessive upper jaw growth. The doctor will try to figure out which of these is causing the problem.
When you smile, your upper teeth should cover anywhere between 75% to 100% of the crowns of your upper teeth, along with some tooth-colored gum tissue. If less than 75% of the crown is visible, typically seen in men, it is considered a low smile line. If the whole crown along with an excessive amount of your gum is seen, typically observed in women, it is considered a high smile line, or a “gummy smile”.
Lastly, the doctor will examine your gums. During this periodontal examination, they will be checking the size of gum tissue tightly bound to the tooth and underlying bone, the level of gum attachment to the tooth, the bone level relative to the part of the tooth where the enamel meets roots (CEJ), and the depth of the gap between the tooth surface and the gum (probing depth). These measurements help the doctor to understand the reason behind a clinically short tooth resulting from inflammation of gums (gingivitis), overgrowth of gums (gingival hyperplasia), the condition where the gums have grown over the teeth (altered passive eruption), or tooth wear.
Treatment Options for Excessive Gingival Display
The choice of treatment for a gummy smile largely depends on what’s causing the issue. Gummy smiles can be due to a single issue or a combination of factors. Several treatments are available, ranging from less invasive approaches like botulin toxin or hyaluronic acid injections, to surgical procedures like gingivectomy and orthognathic surgery. In some cases, orthodontic treatment alone might resolve the issue. Let’s look at these treatments more closely:
Gingivectomy: This procedure involves cutting away excess gum tissue. Sometimes, part of the bone that holds the teeth might also be removed if there’s too much of it – this is referred to as osseous resection. When there’s enough bone, and the distance between the bone to the top of the gum line is more than 3 millimeters, a simple gingivectomy might be all that’s needed. If the bone is near the place where the tooth’s enamel ends, removing the gums alone might affect the structure of the tissues around the teeth, so bone removal might be necessary.
Lip Repositioning Surgery: This procedure lowers the height of your gum display when smiling. It’s accomplished by removing a strip of mucous membrane (the moist tissue lining the mouth) from the lower lip area and pushing the lip down, which in turn moves the junction between your gum and lip down. It is most helpful in cases of a high upper lip and mild excessive upper jaw bone growth. If the excessive upper jaw bone growth is severe, or there’s not enough width of gum tissue, this might not be the best approach.
Hyaluronic Acid Infiltration: In 2018, a unique technique was proposed where hyaluronic acid was injected into the region next to the nose. This works by compressing the muscles that elevate the upper lip, reducing the height of your gum display when smiling. The injection takes place around the most cranial part of the crease running from the nose to the corner of the mouth, about 3 millimeters away from the wing of the nose. This is an alternative to botulin toxin injection, but it might not work for all cases and requires a professional who is well versed in the area’s rich vasculature.
Botulin Toxin A Injection: Botulin toxin acts by causing the muscles to relax, reducing their pull and altering the shape and height of your smile. It targets the upper lip and nose-elevating muscles and requires several injection points on both sides. Ordinarily, the doctor would inject 4 to 6 units across three points next to the groove running down the sides of the nose.
Orthognathic Surgery: In some extreme cases of excessive vertical upper jaw bone growth, the only viable solution might be orthognathic or corrective jaw surgery. The available options include a LeFort osteotomy, which moves the upper jaw upwards and back, or a maxillo-mandibular reposition, which involves repositioning both the upper and lower jaws.
What else can Excessive Gingival Display be?
While there isn’t a specific list of alternate diagnoses for something like excessive display of gums or gum overexposure, it’s still crucial to understand the different conditions that could potentially cause this issue.
What to expect with Excessive Gingival Display
In most instances, a gummy smile can be improved significantly using various treatments. The degree of success depends on the cause of the excessive gum showing. Less invasive procedures, such as injections with botulin toxin (also known as Botox) or hyaluronic acid, can resolve some cases. However, the effects of these procedures tend to be temporary and only last a few months. Some people may require surgery, which can provide permanent results.
Possible Complications When Diagnosed with Excessive Gingival Display
Having an overly visible gum line, often referred to as a “gummy smile”, can negatively affect an individual’s self-esteem and mental wellbeing. This aesthetic issue can cause embarrassment and may result in people trying to hide or restrain their smiles.
Preventing Excessive Gingival Display
If someone shows a large amount of gum when they smile, this is usually seen as a cosmetic issue. The way to address this depends on why there is too much gum showing in the first place.
Doctors need to make sure that patients understand the anticipated outcome of treatment. Additionally, patients need to be informed of any potential treatment risks and agree to proceed with the treatment, knowing these risks.
