Orthodontic Conditions - Open Bite

An open bite is a type of orthodontic malocclusion that occurs in an estimated 0.6% of the U.S. population. An open bite is a type of malocclusion which has no vertical overlap or contact between the anterior incisors.

Causes

Open bite malocclusion can occur as a result of several different reasons. It can be inherited genetically, which leads to a skeletal open bite. It can also be caused by functional habits that can result in a dental open bite. At an early age, an open bite may be caused by a transitional change from the primary teeth to the permanent teeth. Additional factors that can result in an open bite include the following:

• Tongue thrusting
• Sucking the thumb
• Long-term pacifier use
• Macroglossia or an unusually large lounge
• Obstructed airway
• Adenoid hypertrophy
• Nasal concha Hypertrophy

Anterior open bite

An anterior open bite occurs when the front teeth do not touch and there is no overlap between the upper incisors and the lower incisors. Anterior open bites can be caused by functional habits like thumb sucking, tongue thrust or extended use of a pacifier. When thumb or digit sucking habit is present in the late primary to early mixed dentition stages, it can cause different side-effects including the upper teeth flaring out, lower teeth flaring in, an increase in the open bite and the overjet. A posterior crossbite in these children in addition to a decrease in intercanine and intermolar width is also common. The more intense or longer the habit continues, the more prominent the malocclusion case can be.

Extended use of a pacifier has also proved to cause anterior open bites in children. Pacifier use which lasts longer than 18 months, can lead to this malocclusion. Studies have shown that when the sucking habit ceases prior to the eruption of permanent teeth, the open bite will self-correct. In some cases, behavior modification may be successful in eliminating these habits.

Posterior open bite

A posterior open bite occurs when the posterior teeth, such as molars or premolars, fail to touch their tooth counterpart. This is more prevalent in segments where there may be a unilateral open bite or open bite related to one or more teeth. The failure of teeth eruption, which can be due to primary teeth failure or a mechanical obstruction during the eruption phase, can also cause the open bite. In Some cases, lateral tongue thrust may also prevent the eruption of the posterior teeth. As a result, eliminating this habit can be key to successful tooth eruption.

Dental open bite

Dental open bite occurs in patients when the anterior teeth do not touch. However, this type of bite is not accompanied by the skeletal tendency to have an open bite. This type of open bite may happen in patients who have a horizontal or hypodivergent growth pattern. These patients have normal jaw growth and don’t have the long face syndrome. The anterior open bite in these patients may be caused by macroglossia, tongue thrusting or thumb sucking habits.

Behavior Modification Therapy

Behavior therapy can be successful, especially when the child is in their primary dentition in the pre-adolescent age. When habits are modified at this time, it can often lead to the self-correction of an open bite. At times, the presence of infant-like swallowing which continues into early-childhood can lead to an anterior open bite. Controlling these habits using appliances such as a tongue crib or a tongue spurs can also be used in the event the behavior modification fails to prevent the habit.