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Updated on August 1, 2023
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Lopsided Smiles Causes & Treatments

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Most faces are slightly asymmetrical, but some have more noticeable facial imbalances, like an uneven smile. An uneven or lopsided smile means one side of the mouth pulls higher into a smile while the other side droops or remains neutral.

People may be born with naturally lopsided smiles, or it can happen due to:

  • Aging
  • Jaw alignment
  • Nerve damage
  • Muscle weakness
  • Dental issues

Typically, an uneven smile isn't a cause for concern, but if facial symmetry occurs suddenly, it could indicate a medical emergency such as a stroke.

There are treatments available for many causes of a crooked smile. These include orthodontic treatments to realign the teeth and correct jaw misalignment or Botox (botulinum toxin) injections to relax facial muscles.

What Causes a Lopsided Smile? 

Your smile may appear uneven for various reasons. Some are serious and require emergency medical attention, while others are less concerning.

Genetics

You may inherit the same genes if your biological parents have asymmetrical features and a crooked smile. This makes you more likely to have an uneven smile.

Aging

The skin around your mouth can become thinner and lose collagen as you age. The facial muscles can also weaken and sag, and the jawbone can shrink with age. Together, these factors can create an unbalanced appearance.1

Uneven Teeth 

It's normal to have moderately uneven, crooked teeth. Usually, this doesn’t cause a significantly lopsided smile. 

However, your smile can appear lopsided if your teeth are naturally uneven or uneven because of dental issues like tooth decay and weak or broken teeth.  

Jaw Structure

A misaligned jaw can cause an excessive overbite, underbite, or overall poor alignment between the upper and lower teeth. This can cause problems when you bite and chew and also make your smile look unbalanced. 

You can also develop misalignment if the jaw becomes damaged by trauma or disease such as cancer invading the bone.2

Smoking

Smoking can cause facial wrinkles and sagging skin around the mouth, leading to an uneven smile. 

It can also contribute to severe tooth decay, gum disease, or oral cancer, which can affect the appearance and balance of your smile.

Surgical Interventions

You may need facial surgery to remove growths, tumors, or abscesses affecting the nerves and muscles. 

There’s a risk that a surgical error can damage or cut a nerve that controls mouth movement, which can lead to a crooked smile.3

Trauma

A facial injury can damage the underlying structures and cause substantial swelling. As a result, your face can appear uneven and your smile lopsided. 

Bell’s Palsy

Bell's palsy is a temporary weakness or paralysis affecting one side of the face. The cause is often unclear. 

You may notice symptoms developing over a few hours and worsening for several days. They include facial weakness, one corner of the mouth drooping, and the smile line (nasolabial fold) disappearing.4

Facial Paralysis

Various nerve and muscle conditions can cause facial weakness and an uneven smile. They include:

  • Myasthenia gravis — an autoimmune disorder that causes muscular weakness.
  • Multiple sclerosis — an autoimmune condition that damages the protective myelin sheath of nerves in the brain and spinal cord.
  • Amyotrophic lateral sclerosis — a progressive neurological disease that affects how nerve cells control movement.

Torticollis

Torticollis is a condition that can be present at birth or develop later due to injuries or inflammation. It causes neck muscle tightness and spasms. 

If the muscles contract strongly, it can pull the head to one side and cause a lopsided smile.5

Stroke

A stroke is a medical emergency. It happens when the blood supply to the brain is interrupted by a blood clot or burst blood vessel. It can cause weakness on one side of the face and body, slurred speech, and may result in an uneven, droopy smile.

If someone experiences any of the signs or symptoms of a stroke, they should seek medical attention immediately. Immediate treatment may help reduce the risk of long-term disability.6

How to Tell if Your Smile is Lopsided

If you're unsure whether your smile is lopsided, there are a few ways to tell. The most accurate way is to have a dental professional assess the symmetry of your facial features and teeth.

You can also observe your smile in the mirror for any obvious signs it may be asymmetrical. Look at how your eyes, nose, and lips align when you smile. If one side of your face appears higher or lower than the other, your smile may be lopsided.

Finally, ask a close friend or family member if they notice any asymmetries in your smile. They can provide valuable insights about asymmetries that you might be unable to detect.

How to Fix a Lopsided Smile

The best way to fix a lopsided smile is to determine the underlying cause and receive appropriate treatment.

No Treatment

You may not need treatment if your crooked smile is due to genetics and natural asymmetry. 

If due to a temporary condition, such as facial palsy, symptoms should gradually improve on their own within a few weeks to months. However, doctors may prescribe oral steroids to speed up recovery.

Dental Treatments

If a person has uneven teeth or a misaligned jaw, an orthodontist may recommend braces or jaw surgery to correct the issue. Dentists may recommend restorative treatments, such as fillings, root canals, and crowns, in cases of gum disease or tooth decay.

Emergency Treatments

Doctors provide immediate treatment to reduce the risk of long-term effects in a medical emergency like a stroke or severe facial trauma. This may include interventions such as blood thinners for certain types of strokes or surgery for facial trauma. 

Physical Therapy

Following a stroke, facial injury, or nerve paralysis, doctors may recommend physical therapy to restore facial muscle strength and symmetry. 

Physical therapy can involve facial exercises that target the affected jaw muscles. It may also include rehabilitation with specialized equipment like a neuromuscular electrical stimulator.7

Surgery

Surgery may help a misaligned jaw. It can also reconstruct facial nerves and muscles and repair trauma for improved lower-face asymmetry. 

A licensed plastic surgeon can use nerve and tissue grafting and muscle transfers to restore facial structures. They may also suggest cosmetic options such as a lip implant to even out your smile.2

Botox

Botox (botulinum toxin) is a quick injection that can temporarily relax specific facial muscles. It's commonly used for the treatment of wrinkles and fine lines. 

However, it can also treat lopsidedness due to muscle spasms or contractions and gently lift the mouth.

Other Types of Smiles

Besides a crooked smile, there are various types of smiles, including:8

  • Gummy smile — shows too much of the gums above the top teeth.
  • Broad smile — a wide smile with eight to 10 teeth showing and no dark triangles (buccal corridors) in the corners of the mouth.
  • Narrow smile — shows only the front four to six teeth. It's due to a small mouth, teeth misalignment, or missing teeth.

Summary

An uneven or lopsided smile can be due to genetics, dental issues, smoking, aging, or medical conditions.

Treatment depends on the underlying cause and may not be necessary if a lopsided smile is natural or due to temporary conditions like Bell's palsy. Other treatment options include braces, Botox injections, or surgical intervention. 

If someone has an uneven smile following a stroke, they may need physical therapy to help correct facial asymmetry, muscle tone, and strength.

No matter the cause of a crooked smile, regular dental check-ups are essential to maintaining oral health. Your dentist can also assess changes in your smile over time and alert you of potential issues.

Last updated on August 1, 2023
8 Sources Cited
Last updated on August 1, 2023
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Trojahn, C., et al. “Characterizing Facial Skin Ageing in Humans: Disentangling Extrinsic from Intrinsic Biological Phenomena.” Biomedical Research international, 2015. 
  2. Yoshimoto, S., et al. “Static reconstruction of malar region in facial paralysis: A new alternative technique for plasty of symmetric mouth appearance.” Journal of Plastic Surgery and Hand Surgery, 2013. 
  3. Borsook, D., et al. “Surgically-Induced Neuropathic Pain (SNPP): Understanding the Perioperative Process.” Annals of Surgery, 2013. 
  4. Bell palsy.” MedlinePlus, 2022.
  5. Kuo, A. A., et al. “Congenital Muscular Torticollis and Positional Plagiocephaly.” Pediatrics in Review, 2014.
  6. Stroke Signs and Symptoms” The CDC, 2022.
  7. De Stefani, E., et al. “A New Neurorehabilitative Postsurgery Intervention for Facial Palsy Based on Smile Observation and Hand-Mouth Motor Synergies.” Neural Plasticity, 2021.
  8. How Jacquelynn Got a Wider Smile.” The Gorman Center For Fine Dentistry, 2022.
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