Last Updated on November 11, 2025
A smile should frame the teeth first, but for some people, the gums take over. Dentists call it a “gummy smile.” It isn’t harmful, but it can leave people wishing the balance leaned more toward teeth than gums. So, what causes a gummy smile? Sometimes it’s extra gum tissue. Sometimes teeth are short, worn down, or never fully erupted. In other cases, lip movement or jaw growth reveals more gum than expected. Medications, hygiene issues, or genetics also play their part. The truth: no two gummy smiles have the same backstory. To understand it, you have to look at the different causes one by one.
Common Causes of Gummy Smiles
There’s no single explanation. For some, it’s built into their bone structure. For others, it’s daily habits or even side effects of medication. Below are common reasons gums may take the spotlight in a smile.
1. Teeth that don’t fully erupt
Think of it like curtains drawn too low. The teeth are there, full size, but the gums cover more of them than usual. This incomplete eruption makes the teeth look smaller, even though they’re not. Dentists call it altered passive eruption.
2. Extra gum tissue
In some people, the gum tissue is thicker or positioned lower on the teeth. The result: teeth that look shorter, even though they’re perfectly healthy.
3. Teeth worn down by grinding
Years of clenching or grinding gradually shorten teeth. When that happens, the proportions flip. Teeth shrink visually, gums dominate, and the balance feels off. Even slight wear on front teeth can make the change noticeable sooner than you’d expect.
4. Lip position and muscle activity
Sometimes the cause isn’t the gums or teeth at all – it’s the lips. When the upper lip lifts higher than usual while smiling, more gum shows. Dentists refer to this as a hyperactive upper lip, often linked to stronger lip muscles that pull upward with extra force. It doesn’t cause pain or harm, but it changes how the smile looks.
5. Jaw growth and alignment
The jawbone itself can influence how much gum shows when you smile. If the upper jaw develops too far vertically, the gums naturally become more visible. Dentists call this condition vertical maxillary excess. It’s a skeletal issue, driven by upper jaw (maxillary) vertical growth, not the teeth or gums.
6. Genetic traits
Ever notice family members smiling the same way? Genetics plays a quiet but powerful role. Just as you inherit eye color or nose shape, you can inherit a gummy smile. In these cases, the trait comes from biology, not habits.
7. Braces and orthodontic treatment
Orthodontics can shift how the gums frame the teeth. While braces are on, gums can look puffier due to plaque retention and inflammation around brackets. For most people, the balance returns after treatment, but a few may need gum contouring to refine the look when braces come off.
8. Medications that affect gums
Certain prescriptions come with a surprising side effect: gum overgrowth. Anti-seizure drugs, some antihypertensives, and immunosuppressants can all cause gums to thicken. The teeth stay healthy, but the gums become more noticeable every time you smile.
9. Poor oral hygiene
When gums swell from inflammation, they naturally cover more tooth surface. Gingivitis or gum disease can exaggerate gum visibility. The good news: professional cleaning and better hygiene usually reverse the swelling, returning the smile closer to balance.
10. Natural wear and tear
With age, minor wear or erosion can shorten teeth slightly, which can make gums appear more prominent. Gums themselves do not grow, but the teeth look smaller, making the gums stand out.
11. Developmental differences
Occasionally, it’s a mix of small things: how teeth erupted, the thickness of gum tissue, or subtle jaw positioning. Alone, each difference is minor. Together, they create a smile where gums naturally play the lead role.
Conclusion
A gummy smile can trace back to many different causes. Some smiles reveal more gum because the teeth never fully erupted. Others come from extra gum tissue, grinding that shortens teeth, or a lip that rises too high. Jaw development, genetics, and orthodontic changes also matter. Certain medications can thicken gums, while poor hygiene or swelling makes them look larger. Add in natural wear, stronger facial muscles, or small developmental quirks, and the list grows longer. What’s important is knowing that it isn’t one-size-fits-all.
At Riverview Dental Arts, every patient’s smile is evaluated for the real reason behind their gummy look. With the right care, those causes can be managed, and a balanced, confident smile becomes possible.
