Lopsided Smile: Causes and How to Fix an Uneven Smile

Most of the time, there’s nothing to worry about when one corner of your mouth sits a little higher than the other. It can be the way your teeth or jaw are shaped, changes as you age, or something you were born with.

But if a smile suddenly becomes lopsided, call 911. That’s a warning sign of a stroke. Read through these 10 causes of a lopsided smile and how to fix it.

What Does a Lopsided Smile Mean?

In most cases, there’s nothing wrong if your smile is a little lopsided and always has been. Like most features of your face, it’s normal for it to be slightly asymmetrical.

As an expression, a lopsided or crooked grin is half a smile, like a smirk. But when it’s unintentional, and your mouth doesn’t smile evenly when you try to or when you talk, there’s a physical cause. When the lopsided smile started can help narrow it down:

• If it’s always been lopsided: genetics, the shape of your jaw, or the position of your teeth
• If it’s come on slowly: aging, changes in your teeth, or a nerve or muscle condition
• If it started after an injury or procedure: swelling, numbness, or damage to a nerve
• If it came on suddenly: a stroke or a condition called Bell’s palsy (get care right away for these)

What Causes a Lopsided Smile?

The most common causes of a lopsided smile fall into 10 categories. The first 5 are related to your brain, nerves, or facial muscles, and some come on suddenly.

1. Stroke

A stroke cuts off blood flow to part of the brain, from a clot or a burst blood vessel. The first FAST step is asking the person to smile, and a droop alone means calling 911.

If it’s a certain type of stroke (blood clot in the brain) and you’re eligible, medications to dissolve the clot are usually started within 4½ hours of symptoms. For some people, doctors can remove a clot blocking a large brain artery up to 24 hours after symptoms begin.²

If it’s a different type of stroke (bleeding in the brain), it will be treated differently.

2. Bell’s Palsy

Bell’s palsy causes sudden weakness or paralysis on one side of your face due to a problem with the facial nerve. Symptoms include:

• Drooping on one side of your mouth or your eyelid
• Drooling from one side of your mouth
• Changes in your sense of taste, or sounds seeming louder in one ear

Symptoms come on quickly and peak within 72 hours. To help with recovery, a U.S. guideline recommends oral steroid medication within that time frame if you’re 16 or older.⁴

Your doctor will want to rule out a stroke first. Most people recover from Bell’s palsy within a few weeks or months.

If one eye doesn’t close when you try, you’ll need lubricating eye drops or ointment to protect it. Ask your doctor how to keep it safely closed while you sleep, and get care right away for eye pain or vision changes.

3. Facial Trauma or Swelling

While your face is swollen from an injury or a tooth infection that’s left you with a swollen jaw, your smile may be lopsided. Certain facial injuries can also damage the facial nerve, muscles, or bones and make your smile uneven.

4. Dental Numbing or Facial Surgery

After a “shot” for a dental procedure, it’s common for one side of your lip to feel numb and look uneven until it wears off. If it lasts longer than expected, call your dentist.

If your face feels weak or an eye won’t close, get care right away. Call 911 for sudden, unexplained facial weakness or other stroke signs, even after dental work.

It’s not common after routine dental care, but certain surgeries, including on your parotid (salivary) gland, jaw, or temporomandibular joint (TMJ), can sometimes damage the facial nerve.

5. Neuromuscular and Nerve Conditions

Myasthenia gravis weakens the muscles for facial expression, the eyelids and chewing, and rest eases it. ALS (amyotrophic lateral sclerosis) gradually weakens the muscles for speaking and swallowing. These usually build slowly, but sudden facial weakness, slurred speech, or trouble breathing or swallowing that’s severe or getting worse fast means calling 911.

Dental and Lifelong Causes of an Uneven Smile

The next 5 causes are usually not emergencies. They come on slowly or have always been there, and several can be fixed by a dentist.

6. Uneven or Missing Teeth

Slightly crooked teeth don’t usually cause a lopsided smile. But if one side of your smile is noticeably higher or lower than the other, it could be caused by:

• Teeth that came in crooked, too high, or too low
• A missing tooth or a gap on one side
• Worn, chipped, broken, or decayed teeth on one side

7. Jaw Misalignment

A misaligned jaw can throw off your bite, causing an overbite, underbite, or crossbite, and make your lower face unbalanced.

These can cause difficulty chewing and are also one cause of a lisp.

8. Torticollis

Torticollis, a condition that affects the muscles of your neck, from birth or later in life, can make you tilt or turn your head.

The tilt can make the face or smile look uneven. Treatment depends on the cause, and early stretching and positioning work best for babies. If it starts after an injury or with an illness, get medical care right away.

9. Aging and Smoking

As you age, your skin gets thinner and less firm, and the shape of the fat and bone in your face changes. It’s rare for these changes to be perfectly symmetrical, which may cause your smile to tip a bit. Smoking causes extra wrinkles around your mouth and harms your teeth and gums.

10. Genetics

Some people are born with a lopsided smile. Facial asymmetry seems to run in some families, and when it’s lifelong, it’s usually not a health problem unless it affects how you chew or speak.

How to Fix a Lopsided Smile

The right fix depends on the cause. If something new is making one side of your smile droop, you need medical care to find out why.

No Treatment

If your smile has always been slightly asymmetrical, hasn’t changed, doesn’t affect chewing or speech and doesn’t bother you, it usually doesn’t need treatment.

Other causes of a temporary lopsided smile, like numbness from a dental shot or swelling from an injury, usually go away on their own. A tooth infection won’t clear up by itself, so see a dentist right away.

Dental Treatments

If the problem is with your teeth or bite, a dentist may recommend:

• Braces or clear aligners to correct your bite or straighten your teeth
• Bonding, veneers, or crowns to rebuild damaged or uneven teeth
• A bridge or implant to replace a missing tooth

Physical Therapy

If a stroke, Bell’s palsy, or other nerve damage caused your smile to droop, a physical therapist can teach you exercises for the muscles that control facial expression. A review of studies found that physical therapy exercises for people with facial palsy like Bell’s palsy seemed to help, but there’s only low-quality evidence.¹¹

Surgery

Corrective surgery can reposition your jaw. It’s usually done along with braces to fix a bite problem.

If facial nerve damage is causing a one-sided smile, surgeons can repair or graft the nerve, transfer a nearby nerve, or move a muscle. Timing is important, so talk to a specialist as soon as possible.

Botox

Botox (botulinum toxin) can relax muscles for a few months at a time.

It won’t help if your smile just started to droop. See a doctor to find out what’s wrong first.

When to See a Dentist or Doctor

A lopsided smile you’ve always had rarely needs a doctor. A new, sudden or worsening one does, and how fast depends on how it started.

Call 911 for These Stroke Signs

Call 911 right away if any FAST sign comes on suddenly, even just one:

• Face: one side of the face droops or feels numb
• Arms: one arm drifts down when both are raised, or an arm or leg feels weak or numb
• Speech: slurred or strange speech, or trouble speaking or understanding others
• Time: note when symptoms started, and call even if they fade

Other sudden signs need the same call: confusion, trouble seeing or walking, dizziness or loss of balance, or a severe headache with no known cause. Don’t drive to the hospital or have someone drive you, because an ambulance crew can start care on the way.¹

Get Care the Same Day

If a droop is new and you aren’t sure whether it’s a stroke, call 911, even if it’s the only sign. Get care the same day for:

• Facial weakness that builds over hours or days: see a doctor today, and don’t assume it’s Bell’s palsy. If it is, treatment works best when it starts within 72 hours.
• New or worsening trouble swallowing: see a doctor the same day. Call 911 if trouble breathing or swallowing is severe or getting worse fast.
• After a facial injury: go to the ER if your jaw looks out of place or won’t close, your bite has changed, or your vision changes. If numbness is your only symptom after a minor injury, go to urgent care the same day.
• A smile change or lasting numbness after a procedure: call your dentist or surgeon today. Call 911 instead for sudden, unexplained facial weakness or other stroke signs.
• Facial swelling: see a dentist the same day if it may be from a tooth infection, even without a toothache or fever. If you also have a fever and can’t see a dentist right away, go to the ER. Swelling with a fever but no clear dental cause needs medical care the same day.
• Swelling with warning signs: go to the ER if it spreads fast or toward your eye or neck, or you have trouble opening your mouth. A swollen or painful eye, vision changes or a lot of swelling inside your mouth also need the ER. Call 911 for trouble breathing or swallowing.

Book an Appointment

• Your doctor: Bell’s palsy that hasn’t started to improve after three weeks or isn’t fully better by three months. Go back promptly for new or worsening symptoms, and get care right away for eye pain or vision changes. Call 911 for sudden stroke signs.
• Your doctor, promptly: facial weakness that creeps in, especially with drooping eyelids or double vision
• A dentist: shifting, missing or damaged teeth, or a changed bite
• An orthodontist or cosmetic dentist: a lifelong uneven smile you’d like to change