What Causes Crooked Teeth?

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Affecting about one in every two people worldwide, having crooked teeth, or malocclusion, can significantly impact the self-esteem of both children and adults. Misaligned bites, overbites, underbites, crowded teeth, and related issues can be caused by a range of factors, with genetics and certain behaviors the most common.

While having crooked teeth primarily impacts feelings of self-worth, it can also cause difficulty chewing and swallowing, and, in rare cases, speaking. Luckily, there are a number of options for teeth straightening, including metal braces, clear aligners, retainers, and veneers, among others.

Cheerful teenage girl with braces cleaning her teeth in bathroom

Sladic / Getty Images

What Causes Crooked Teeth?

Perfect teeth, with the upper set fitting a little over the lower and the molars interlocking appropriately, are relatively rare. However, most issues are minor, and many don’t require treatment.

Malocclusion arises due to mismatches between the sizes of the upper jaw and lower jaw. It can also occur when the teeth are not the correct size for the jaw. A range of factors—everything from genetics to dental hygiene—can cause this to happen.


A great deal about the alignment of your teeth is determined by genetics. A family history of crooked teeth predisposes you to having them yourself, and it’s an inherited trait.

Birth Defects

Babies born with cleft palate, a birth defect in which tissues of the roof of the mouth (palate) do not fully form, are prone to developing crooked teeth. This is also the case for cleft lip, cases in which this malformation has affected the upper lip.

Thumb Sucking

Thumb sucking can significantly affect tooth formation and is a common cause of misalignment. While this, or others like it, such as using a sucker or pacifier, are normal until the age of three, they can become problematic afterward.

Tongue Thrusting and Forward Posturing

Another issue that creates tooth misalignment is tongue thrusting (sometimes referred to as tongue thrust).

Occurring primarily in infants and children, this is when your tongue touches the upper teeth every time you swallow. Arising either due to issues with jaw structure or a tongue that’s too large, tongue thrusting can cause crooked teeth over time.

The signs of this behavior may include:

  • Open bite (the front teeth never join when closed)
  • Visible tongue between the teeth
  • Mouth breathing
  • Lisp, trouble articulating s’s and z’s
  • Difficulty swallowing and chewing
  • Messy, fast, or very slow eating

Facial Injury

Fracture of the jawbone and/or skull—as in a severe fall or accident—can significantly impact tooth alignment. As they heal from the injury, the upper and lower jaw can become deformed or mismatched, which leads to crooked teeth.

Poor Dental Care

Problems with dental health, especially when you’re growing up, are another common cause of crooked teeth. These may include:

  • Extra teeth
  • Missing teeth
  • Poorly fitting dental crowns, tooth fillings, braces, or other dental instruments
  • Abnormally shaped teeth
  • Impacted teeth (when the tooth puts pressure on a bone or other tissue)

Keep Up With Dental Hygeine

Ensuring your teeth are healthy can also help prevent malocclusion. This means brushing properly twice a day, flossing at least once a day, and avoiding certain foods and drinks.

Other Causes

Crooked teeth can also occur due to a couple other factors, which include:

  • Tumor growth on the jaw or in the mouth
  • Lip biting and sucking
  • Habitually breathing from the mouth
  • Early loss of baby teeth


A range of factors lead to crooked teeth. They can run in families or be caused by birth defects, behaviors like thumb sucking or tongue thrusting, injury, or poor dental care.

Problems Caused by Crooked Teeth

The primary issue caused by crooked teeth is the impact it can have on self-esteem. Since society places a great deal of emphasis on symmetrical teeth and smiles, many who have misalignments feel unattractive and stigmatized. Taking care of the issue is often a means of restoring self-worth.

In addition to issues with self-esteem, misaligned teeth can also cause:

  • Altered shape and appearance of the face
  • Trouble chewing or biting
  • Speech difficulties, such as a lisp
  • Mouth breathing (through the mouth, while it’s open)
  • Inability to bite food properly

Treatment for Crooked Teeth

Orthodontic approaches to crooked teeth have come a long way. Alongside more traditional metal braces and hardware are a range of newer methods, such as using clear aligners or veneers. It’s important to carefully consider your options.

Metal Braces

Metal braces are a fundamental orthodontic technique, especially for adolescents. Placed onto teeth using bonding agents, brackets are wired together and tightened over time. Rubber bands, springs, or other instruments may also be used to help pressure teeth and encourage better alignment.

When used anywhere from six months to a couple of years, braces are effective in correcting alignment problems. Generally, metal braces are a less expensive treatment. However, in addition to being visible, there are periods of pain and soreness associated with this approach.

Additionally, ceramic braces and those employing lingual brackets—in which the brackets are on the inside of the teeth—are types of braces that more easily blend into the surrounding teeth.

Clear Aligners

Clear aligners, such as the Invisalign system, are another common approach, popular because they’re not as visible when worn.

Taken off when eating and brushing, these are wearable sets of plastic trays designed to adjust the position of your teeth. Every two to three weeks, you’ll need a new set to continue the gradual process of tooth straightening.

Though effective in aligning teeth, this approach is typically reserved for more minor cases of malocclusion.


In addition to aligners, wearing a retainer can also help more mild alignment problems. Special retainers, such as a spring aligner, can be used for minor alignment problems.

Retainers are specially designed for the contours of your mouth to put strategic pressure on your teeth. Like aligners, retainers are less visible and can be taken off for eating and dental hygiene.

Retainers are almost always given to patients after treatment to maintain the results. There are many retainer designs, some of which are clear and others that have metal. Your dental healthcare professional will discuss and prescribe what is best for you.


Also used as a means to whiten teeth or correct them when chipped, veneers are thin shells crafted to fit over your front teeth to improve their appearance. These can help as a cosmetic dentistry approach to fill in gaps or irregularities in this part of your smile.


Treatments for crooked teeth vary based on the severity of the case; however, they are generally successful in correcting problems. They include everything from metal braces and clear aligners to retainers, which are worn to adjust the position of teeth through pressure. In some cases, veneers—specialized shells placed over front teeth—can help with milder malocclusion.


Crooked teeth, which can significantly impact self-esteem, are very common in both children and adults. Causes of the condition include genetics, birth defects, facial injuries and missing teeth, and childhood behaviors, such as thumb sucking.

There are many teeth-straightening treatments, such as wearing metal braces, clear aligners, retainers, and veneers, among others.

You should always seek a consultation from a dental healthcare professional who specializes in fixing crowded and crooked teeth, such as an orthodontist.

A Word from Verywell

While crooked teeth can impact your self-esteem and sense of self-worth, it’s important to note that nowadays there are more options than ever before for straightening them.

Older methods, such as wearing metal braces, have become better, and a range of newer treatments—including clear aligners and retainers—have grown in popularity.

It’s never too late to start correcting crooked teeth. With treatment, there will be no need to hide your teeth or to feel self-conscious about them—there will be no need to hide your smile.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Mark Gurarie
Mark Gurarie is a freelance writer, editor, and adjunct lecturer of writing composition at George Washington University.