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Malocclusion of the teeth is when your teeth are misaligned. This can lead to oral health complications if left untreated. It may also be referred to as:

  • crowded teeth
  • crossbite
  • overbite
  • underbite
  • open bite

Your teeth may not perform vital functions well, like chewing, if they’re misaligned. Learn more about this condition and how it may be treated to protect your overall oral and digestive health.

Occlusion refers to the alignment of your teeth. Typically, your teeth should fit easily inside your mouth without any crowding or spacing concerns. Also, your teeth should not be severely rotated or twisted.

Your upper jaw teeth should slightly overlap with your lower jaw teeth so that the pointed ridges of your upper molars fit into the grooves of your opposite molars.

Changes in alignment of your typical occlusion are known as malocclusion. The types of changes vary, but any type of misalignment is important to address.

A dental health professional can help make sure that your upper teeth are properly aligned.

Alignment of your upper teeth will prevent you from biting your cheeks and lips. You also need to work with a dental health professional to make sure that your lower teeth are aligned so you can protect your tongue.

Malocclusion is usually an inherited condition. This means it can be passed down from one generation to the next.

There are some conditions or habits that may change the shape and structure of your jaw. These include:

  • cleft lip and palate
  • frequent use of a pacifier after you’re 3 years old
  • prolonged use of bottle feeding in early childhood
  • thumb sucking in early childhood
  • injuries that result in the misalignment of your jaw
  • tumors in your mouth or jaw
  • atypically shaped or impacted teeth
  • dental care resulting in improperly fitting dental fillings, crowns, or braces
  • airway obstruction (mouth breathing), potentially caused by allergies or by enlarged adenoids or tonsils

Depending on the classification of malocclusion, the symptoms of the disorder may be subtle or severe. Typical symptoms of malocclusion include:

  • improper alignment of your teeth
  • changes in the appearance of your face
  • frequent biting of your inner cheeks or tongue
  • discomfort when chewing or biting
  • speech changes, including the development of a lisp
  • breathing through your mouth rather than your nose

Malocclusion of teeth is typically diagnosed through routine dental exams. Your dentist will examine your teeth and may perform dental X-rays to determine if your teeth are properly aligned.

If your dentist detects malocclusion, they will classify it by its type and severity. There are three major classes of malocclusion:

Class 1

Class 1 malocclusion is diagnosed when your upper molars overlap with your lower molars in a good position, but your other teeth are crowded or spaced too far apart.

In this type of malocclusion, the bite is typical and your teeth misalignment is not severe. Class 1 malocclusion is the most common classification of malocclusion.

Class 2

Class 2 malocclusion is diagnosed when you have a severe overbite. In this type of malocclusion, your upper teeth and jaw significantly overlap with your lower teeth and jaw.

If a class 2 malocclusion happens when you have a smaller than usual lower jaw, it is also known as retrognathism (or retrognathia).

Class 3

Class 3 malocclusion is diagnosed when you have a severe underbite. In this type of malocclusion, your lower teeth overlap with your upper teeth.

This type is usually caused by a large lower jaw and is known as prognathism, meaning that your lower jaw protrudes forward.

Most people with mild malocclusion will not require treatment. However, your dentist may refer you to an orthodontist if your malocclusion is severe.

Depending on your type of malocclusion, your orthodontist may recommend various treatments. These can include:

  • braces to correct the position of your teeth
  • dental appliances or retainers to realign teeth
  • removal of teeth to correct overcrowding
  • reshaping, bonding, or capping of teeth
  • surgery to reshape or shorten your jaw

Treatment for the condition may also result in some complications. These include:

  • tooth decay
  • pain or discomfort
  • irritation of your mouth from the use of appliances, such as braces
  • difficulty chewing or speaking during treatment

Preventing the condition can be difficult because most cases of malocclusion are largely hereditary.

However, growth of your jaw and teeth can also be influenced by environmental factors, according to a 2018 research review.

Parents of young children should limit pacifier and bottle use to help reduce changes in the development of the jaw. Children should also be encouraged to stop sucking their thumbs as young as possible.

Early detection of malocclusion may help decrease the length and severity of the treatment.

A dental professional can typically correct malocclusion of teeth in children and adults.

Receiving early dental treatment in childhood can help reduce the treatment duration and may lead to fewer dental expenses in the long run.

Adults can also get good results. However, treatment for adults will generally take longer and may be more costly. The earlier you treat malocclusion, the better the outcome.