Malocclusion simply refers to the misalignment of teeth, which ranges from minor dental crowding to severe overbites or underbites. Teeth misalignment is commonly passed down through genetics.
Most people aren’t born with normal occlusion (a perfect bite) and turn to orthodontic treatment for long-term solutions.
Crowded teeth, gaps, and other forms of misalignment are all caused by the difference in teeth and jaw size. There is usually not enough room for permanent teeth to grow in properly.
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Other common causes of malocclusion include:
The symptoms of malocclusion are usually obvious, but some are subtle, and may include:
There are three different classes of malocclusion, referred to as class I, II, and III:
Within these three classes, there are seven different types of misalignment a patient can have. Treatment options also vary depending on age and the type of malocclusion:
An overbite is a class II malocclusion that occurs when the lower jaw is in an improper position. As a result, the upper teeth and jaw have too much overlap with the lower teeth and jaw. It can be attributed to genetics (skeletal), childhood sucking habits (dental), or a combination of the two.
An overbite should be treated as soon as possible. If it is left untreated, there is a higher risk of developing a jaw disorder, gum disease, or tooth decay over time.
Common overbite treatment options include:
An underbite is a class III malocclusion that occurs when the lower jaw is pushed forward. As a result, the lower teeth and jaw overlap the front teeth and jaw. There are two different types of underbites, including dental or skeletal.
A dental underbite is usually caused by a crossbite, while a skeletal underbite is caused by a malformation of the jawbone (genetics). Similar to an overbite, an underbite should be treated as early as possible to prevent the development of other dental conditions.
Common underbite treatment options include:
A crossbite is a class II malocclusion that occurs when a few bottom teeth are located outside the upper teeth when the mouth is closed. Genetics, mouth breathing, delayed permanent teeth eruption, and childhood habits (e.g. thumb sucking) can cause this form of malocclusion.
Many people confuse crossbites and underbites, but they are completely different forms of malocclusion. Although, someone with an underbite typically has a crossbite. This form of malocclusion can either affect the anterior teeth, posterior teeth, or both.
Common crossbite treatment options include:
An open bite is the rarest form of malocclusion. It occurs when the upper and lower teeth slant outwards and do not touch when the mouth is closed. An open bite can either affect the anterior teeth or posterior teeth.
Skeletal (genetic) or dental (irregular tooth eruption) factors can cause this condition. Additionally, untreated open bites typically result in speaking problems and issues tearing and chewing food.
Common treatment options for open bites include:
An overjet (upper front teeth protrusion) is usually caused by a class II malocclusion, which is when the upper teeth are ahead of the lower teeth.
Overjets can be attributed to genetic factors, childhood habits, and/or irregular skeletal development. Untreated overjets can result in temporomandibular joint disorder (TMD).
Common treatment options for overjets include:
Dental crowding, also referred to as crowded teeth, occurs when there is not enough space in the mouth for permanent teeth to grow in straight. Crowding is a class I malocclusion that typically only affects the anterior teeth.
This form of malocclusion can be due to abnormal jaw development (genetics), irregular tooth eruption or loss, and normal aging.
Common treatment options for dental crowding include:
Diastema is when there is a space or gap between two or more teeth. Gaps can range from barely noticeable to large. Midline diastema, which appears as a gap between the two upper front teeth, is the most common.
Common treatment options for spaced teeth and diastema include:
Cobourne, Martyn T., and Andrew T. DiBiase. Handbook of Orthodontics. Elsevier, 2016., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914920/
Sterling, Evelina Weidman. Your Childs Teeth: a Complete Guide for Parents. Johns Hopkins University Press, 2013.