Can Invisalign Fix a Gummy Smile?

Published by Piedmont Dental By Design | Piedmont, CA

Quick Answer

Sometimes, and the dividing line is what is causing the gum to show. If your upper front teeth have over-erupted or sit in a deep bite, Invisalign® can move them back up into the bone, and less gum shows as a result. If the cause is gum tissue that never finished receding, a short or hyperactive upper lip, or an upper jaw that grew long, aligners will not change any of it — those need crown lengthening, lip treatment or surgery instead. Many gummy smiles have more than one cause at once, which is why the examination decides the answer, not the treatment name.

Key Takeaways

• Clinicians generally call it a gummy smile when more than 2 to 3 mm of gum shows on a full smile, though some use a 4 mm threshold.
• Aligners move teeth. They do not move gum tissue, lip muscles or jawbone, so they only address one of the four common causes.
• Intrusion — lifting a tooth back up into the bone — is the movement a tooth-caused gummy smile needs, and it is one of the least predictable movements clear aligners perform.
• Gum-tissue causes are treated by crown lengthening, which reshapes both gum and a small amount of bone and does not grow back.
• A hyperactive or short upper lip is the most commonly reported cause in the literature, and no orthodontic treatment addresses it.
• Having two causes at once is normal, which is why plans are often staged rather than a single procedure.

Overview

If you have typed this question into a search bar, you have probably noticed the answers split into two camps. Orthodontic practices tend to say yes; periodontal practices tend to say no. Both are describing real cases, and they disagree because "gummy smile" describes what you see in the mirror rather than a diagnosis. Four quite different things produce the same look, and only one of them is a tooth-position problem that aligners can act on.

This guide sets out what counts as a gummy smile and how common it is, the causes and what each one looks like, when clear aligners help and what the published accuracy data says about how reliably they do it, when crown lengthening is the right answer instead, what treats the lip and the jaw, and how a dentist works out which cause is yours. If you want the practice's own summary of the options first, our gummy smile resource page covers them briefly.

What Counts as a Gummy Smile?

There is no single agreed number, which is worth knowing before you decide you have one. A 2023 narrative review in Cureus states that more than 2 to 3 mm of gingival exposure during smiling is considered to be a gummy smile (opens in a new window). A 2025 review of lip repositioning techniques puts the threshold slightly higher, describing 1 to 3 mm of gum visibility as the ideal smile and gingival display exceeding 3 mm as regarded as unattractive globally (opens in a new window). The clinical education journal Decisions in Dentistry is more conservative again, stating that a smile is considered unattractive when more than 4 mm of the gingiva is exposed (opens in a new window).

So the honest answer is a band rather than a line: somewhere between 2 and 4 mm, with most sources settling on 3 mm. You will see 2 mm quoted confidently on a lot of dental websites, and it sits at the very bottom of the published range — which is worth knowing, because a millimeter either way separates a smile a clinician would call normal from one they would work up for treatment.

It is also more common than most people assume, and considerably more common in women. The same Cureus review reports the incidence at approximately 14% in females and 7% in males, and a separate 2023 cross-sectional study puts the overall prevalence at 10.5% to 29% across young adults, with a higher frequency in women (opens in a new window). None of that makes it a health problem on its own. It is a proportion question, not a disease.

Where the gum shows matters as much as how much of it does. The Mazzuco and Hexsel classification, described in the same review, sorts gummy smiles into four patterns: anterior, where more than 3 mm shows between the canines; posterior, where the front looks normal but more than 3 mm shows behind the canines; asymmetric, where one side shows markedly more than the other; and mixed, where both regions are affected. That pattern is a clue to whether the muscles of the upper lip are involved, since different muscle groups produce different patterns.

What Causes a Gummy Smile?

The published lists vary slightly in wording but land in the same place. The Cureus review attributes excessive gingival display to altered eruption of the teeth, hyperactive or short upper lip muscles, vertical maxillary excess, or dentoalveolar extrusion. In plainer terms, that is gum, lip, jaw and tooth position. Worn-down teeth belong on the list too, because a shorter tooth makes the gum above it look longer.

Tooth Position and Over-Eruption

This is the one aligners can act on. Upper front teeth can drift down further than they should, either because they over-erupted during development or because a deep bite let them keep coming down over the years without an opposing tooth to stop them. The gumline follows the tooth, so the whole front section sits lower than it should, and more gum shows above it. If your bite is deep — your upper front teeth cover a lot of the lower ones when you close — this is worth investigating as the cause.

Gum Tissue That Never Finished Receding

Teeth erupt in two phases. In the second, passive phase, the gum migrates up the tooth to settle near the point where the enamel meets the root. When that phase does not complete, the gum stays low and covers part of the crown permanently. The teeth are in the right place; they just look short because a strip of them is still under gum. This is called altered passive eruption, and it is one of the most common causes. No amount of tooth movement fixes it, because nothing is in the wrong position.

A Short or Hyperactive Upper Lip

The muscles that lift the upper lip can pull it higher than average when you smile, exposing gum that stays covered at rest. The Cureus review names this as the most commonly reported cause of a gummy smile, and the lip repositioning review found that roughly 40% of cases are of isolated soft-tissue origin, with a further 35% to 40% caused by a combination of a hyperactive upper lip and altered passive eruption. A short upper lip produces the same effect for a different reason. Neither is a dental problem, and neither responds to orthodontics.

An Upper Jaw That Grew Long

Vertical maxillary excess means the upper jaw developed longer in the vertical dimension than the rest of the face, which carries the whole tooth-and-gum block downward. This is the least common of the four and the most involved to correct. The 2025 case report Interdisciplinary Management of Severe Excessive Gingival Display notes that Le Fort I maxillary impaction remains the treatment of choice for severe skeletal gummy smiles associated with vertical maxillary excess (opens in a new window) — jaw surgery, in other words, usually planned alongside orthodontics.

Worn or Short Teeth

Years of grinding, acid erosion or ordinary wear shorten the visible tooth without changing the gumline, and the proportion tilts. The fix here is restorative rather than orthodontic or surgical: lengthening the teeth back to their proper proportions with porcelain veneers or bonding. It is often combined with gum work, because restoring height on a tooth whose gumline is also too low only solves half the problem.

When Can Invisalign Actually Help?

Clear aligners help when the answer to "why is the gum showing" is "because the teeth are too far down". The movement that fixes this is intrusion: pushing a tooth back up into the bone so the gumline travels with it. That is a real, documented aligner movement, and it is the mechanism behind every honest yes to this question.

A 2026 retrospective study of 30 patients with deep bite, published in Bioinformation, measured what aligners achieved: overbite reduced from 5.5 ± 0.7 mm to 2.3 ± 0.6 mm, through maxillary incisor intrusion of 1.7 ± 0.4 mm and mandibular incisor intrusion of 1.4 ± 0.3 mm (opens in a new window), with minimal molar extrusion. Treatment averaged 14.1 ± 2.0 months, and 8 of the 30 needed refinement aligners. That study measured bite correction rather than gum display, so read it as evidence of the movement rather than of the cosmetic result. But a couple of millimeters of intrusion on the upper front teeth is the same couple of millimeters that separates a smile most clinicians would call normal from one they would not.

How Predictable Is Intrusion With Aligners?

This is where most articles on this topic go quiet, and it is the part worth knowing. Intrusion is among the hardest movements to achieve reliably with aligners.

A 2025 systematic review in the Journal of Clinical Medicine pooled eight clinical trials on incisor intrusion with clear aligners and found mean intrusion values ranging from 0.4 to 1.5 mm, with predictability between 35% and 65% (opens in a new window). Predictability was notably lower in adults, at 45.3%, than in adolescents, at 63.5%, and accuracy declined once more than 2 mm of intrusion was planned. A 2026 scoping review in Frontiers in Dental Medicine reports a similar picture, putting incisor intrusion accuracy at 33.4% to 53.3% and recommending 50% to 100% overcorrection (opens in a new window) to land the planned result.

Read plainly: if the plan calls for 2 mm of intrusion, roughly half of it is a realistic expectation from the first series of aligners, and refinements are normal rather than a sign something went wrong. That is not an argument against aligners — it is an argument for asking how much movement your plan requires, and for treating a confident promise of a specific millimeter result with some caution.

Where Aligners Stop

The University of Iowa College of Dentistry, reviewing what the ADA and NIH say on the subject, puts the limit simply: clear aligners may not be suitable for severe tooth rotations, vertical movements, or complex bite corrections (opens in a new window). Vertical movement is exactly what a tooth-caused gummy smile needs, which is why the honest answer to this question is conditional rather than enthusiastic.

Fixed braces are not automatically better, either. Systematic reviews of complex and extraction cases find fixed appliances achieve better tooth inclination and occlusal contacts in the harder cases, while aligners hold clear advantages in comfort and in gum health during treatment. It is a case-by-case judgement, not a verdict. Our guide to Invisalign versus braces for East Bay adults works through that comparison in full, and the Invisalign treatment page covers how the aligners themselves work.

What aligners categorically cannot do is change gum tissue, relax a lip muscle or shorten a jaw. If your gummy smile comes from any of those, a plan that promises an aligner result is describing a different patient's case.

When Is Crown Lengthening the Answer?

When the gum itself is the problem. The American Academy of Periodontology describes the procedure directly for this purpose: for patients whose smile is too gummy or whose gums cover too much of some teeth, excess gum tissue is removed to expose more of the crown of the tooth (opens in a new window), and the gumline is then sculpted. It is a short procedure under local anesthetic, and for a cosmetic case it is normally carried out across the visible front teeth so the new gumline is symmetrical rather than corrected in one spot.

Recovery is measured in weeks rather than months of downtime. Initial soft-tissue healing takes around 10 to 14 days, and the gumline settles into its final position over roughly two to three months. Teeth look noticeably longer straight away, which is the point of the procedure rather than a side effect. You can read the full walkthrough on the crown lengthening page.

Crown Lengthening or Gum Contouring?

These get used interchangeably online and they are not the same procedure. The distinction is whether bone is involved, and it determines whether the result lasts.

Sequencing When Veneers Are Part of the Plan

If veneers or crowns are going onto the same teeth, the gum work comes first and the restorations wait for full healing. Placing porcelain against a gumline that is still settling risks a margin that looks wrong three months later, once the tissue has finished moving. This is the most common reason a gummy smile plan runs across several months rather than a single visit, and it is worth knowing early so the timeline does not come as a surprise.

What Treats the Lip and the Jaw?

Neither of these is dentistry in the ordinary sense, and both sit outside what any aligner can influence. They matter because a lip cause is, by the published counts, the most likely single explanation for a gummy smile.

For a hyperactive upper lip, botulinum toxin is the conservative option. Small injections relax the muscles that over-lift the lip, so it rests lower on a full smile. The Cureus review found the effect is usually visible within one to two weeks and lasts four to six months, after which re-injection is needed — a genuine limitation rather than a footnote, since it makes this an ongoing commitment rather than a one-off correction. Piedmont Dental By Design refers patients to a trusted provider when this is the right route.

Lip repositioning surgery is the longer-lasting alternative for the same cause. The 2025 review of current techniques notes it is recommended particularly for excessive gingival display linked to a hyperactive or shortened upper lip, and for mild vertical maxillary excess. For severe skeletal cases, jaw surgery is the documented treatment of choice, planned jointly with a surgeon and normally combined with orthodontic preparation before and after.

How Do You Tell Which Cause Is Yours?

Not from a photograph, and not from an article. But the process a clinician follows is not mysterious, and knowing what is being measured makes the consultation easier to follow.

The Measurements That Separate the Causes

Decisions in Dentistry sets out the reference figures. The average maxillary central incisor is 10 to 11 mm long, so a front tooth measuring noticeably less than that points towards gum covering part of it rather than a tooth in the wrong place. Upper lip length, measured from the base of the nose to the lower border of the lip, normally runs 22 to 24 mm in men and 20 to 22 mm in women. And a lip that travels roughly one and a half to two times further than normal on smiling indicates hypermobility rather than anything dental.

Alongside those, a clinician checks where the gum margin sits relative to the point where enamel meets root, your overbite and overjet, and — on a radiograph — the bone level and the vertical dimension of the upper jaw. Those few measurements are what turn "my smile is gummy" into a specific cause with a specific treatment attached.

Questions Worth Asking at a Consultation

Four questions get you most of the way to understanding your own plan, and they work anywhere.

• Which of the four causes is driving mine, and is more than one involved?
• If the plan involves aligners, how many millimeters of intrusion does it call for?
• Will the result need gum work, restorative work, or both, and in what order?
• What does the plan look like if the aligner result falls short of the projection?

A smile design consultation is where those get answered properly, with photographs, measurements and a plan you can see before anything begins.

Can You Have More Than One Cause at Once?

Frequently, and this is the part that gets lost in a straight yes-or-no answer. The lip repositioning review found that roughly 35% to 40% of cases involve a combination of a hyperactive upper lip and altered passive eruption — two causes, needing two quite different treatments, in the same smile.

That is why combined plans are ordinary rather than a sign of overtreatment. A common sequence is crown lengthening to correct the gum proportions, then veneers once the tissue has settled, with aligners before either if the tooth positions also need work. It is equally reasonable to start with the most conservative option and decide later whether to add anything. Which is why "can Invisalign fix a gummy smile" is not quite the question worth asking. "What is causing mine, and what is the least I need to do about it" is.

If aligners do turn out to be part of your answer, our guide to what Invisalign costs in the East Bay covers the tiers, the timeline and how orthodontic insurance actually works.

Frequently Asked Questions

Find Out What Is Actually Causing Yours

The difference between an aligner case and a gum case is a few measurements. It is worth having the cause identified before committing to anything, because the same smile can be improved by three quite different procedures and only one of them will be the least invasive route to the result you want.

Piedmont Dental By Design sees patients from Piedmont, Oakland, Montclair, Rockridge and across the greater East Bay for cosmetic consultations, and will talk through what is driving your gum display and what the realistic options are. The practice is at 1331 Grand Avenue, Piedmont, CA 94610. To arrange a visit, get in touch or call (510) 350-3937.