Anterior Open Bite

What Is an Anterior Open Bite?

An anterior open bite is a form of malocclusion characterized by the absence of incisal overlap in the vertical dimension (between the upper and lower teeth) while biting or during the full closure of the mouth. This term was first coined by Caravelli in 1842. The open bite in the anterior segment of the upper or lower jaw may have dental, skeletal, or often combined etiologic factors. Whatever the etiology of malocclusion, it primarily causes a deviation in the vertical relationship that should be otherwise maintained between the maxillary and the mandibular arches of the orofacial cavity.

Though the prevalence of a simple (not severe) anterior open bite decreases over a phase until young adolescence, it is maximum at six years with a 4.2 percent approximation in children. When diastema or spacing between the anterior teeth is present along with this anterior occlusal relationship, it may further negatively impact the smile line of the individual.

What Are the Clinical Characteristics of an Anterior Open Bite?

The clinical features in patients suffering from the anterior open bite may be mainly due to the obstruction of the nose (blocked nose) before and during puberty in young adults. Also, these patients have hyperactivity of the tongue during swallowing or even at a resting position. Both these factors can affect or alter the axial inclination angle of the incisors, leading to anterior or posterior open bites, as attributed to hypotheses in the dental literature.

How Is Anterior Open Bite Classified?

An anterior open bite, from an etiological point of view, can be mainly classified into two categories:

• Dental anterior open bite often results from an impediment in the sequence or a consequence of delayed dental eruption or altered tooth-bound inclinations.

• Skeletal open bite in the anterior segment is mainly due to the increased facial growth in the posterior region of the jaw or face.

What Causes an Anterior Open Bite?

Anterior open bites, thus, as elaborated, can exist for several reasons, though it is crucial to identify the exact and most common etiology that varies from patient to patient. The dental surgeon or the orthodontist should elicit medical and dental history before beginning the treatment plan, and any restorative, prophylactic, or other surgical corrective procedures for the dentition need to be resolved ideally before beginning orthodontic treatment for long-term success and good prognosis. The causes include:

1. Intra-Arch Disturbances: Open bites, be it anterior or posterior, as per research, occur due to alterations of tooth position, especially within an arch (intra-arch malocclusion). Common risk factors or examples of causing open bites include:

• Thumb sucking.

• Problems in the tongue posture or potential issues in patients (young adults who suffer from airway disorders).

• Excessive wear out in a segment due to appliances (anterior bite plane).

• Abnormal dental eruption due to ankylosis (tooth fusion).

2. Inter Arch Disturbances: When open bites occur due to alterations because of the relationship between the mandible to the maxilla, or interarch malocclusion, then the risk factors include:

• Degenerative joint diseases.

• Class II or III skeletal malocclusion.

• A mandibular plane angle that is moderate to extremely steep (this can be observed in patients with long facial contours).

• Suppose there is tooth wear without the secondary or compensatory eruption of the dentition. A good example is patients who have erosive tooth wear due to citrus fruit sucking or deposits (causing enamel tooth wear). Still, the compensatory eruption may not keep up with this wear rate, causing inter-arch disturbances.

How Is Dental or Skeletal Malocclusion Diagnosed and Treated?

The orthodontist or the dental surgeon can recommend laboratory tests like DC/TMD (diagnostic criteria for temporomandibular disorders) for detecting and examining open bite malocclusion in detail. Cone beam computed tomography is the widely used radiographic modality to analyze and differentiate between anterior and posterior open bite cases.

1. Occlusal Equilibrium: The dentist will also examine the tooth exposure to determine the smile line and the desired anterior position of the maxillary to mandibular teeth without affecting any occlusal changes. But if the occlusal changes are necessary, then occlusal equilibration is established by alteration of the posterior bite and by reshaping the anterior teeth to efficiently produce a contact between the anterior teeth of both arches. However, the disadvantage in some cases with occlusal equilibrium is dentinal hypersensitivity because of tooth reduction, especially when it is excessive to establish anterior contact.

2. Restorations and Equilibration: To close a simple case of anterior open bite, the dentist may also use restorative modalities coupled with occlusal equilibration if the above method is alone, not sufficient to achieve the desired anterior bite or there is an exceeding risk of dentinal hypersensitivity in the patient.

3. Orthodontic Therapies: The treatment of open dental bites is managed by the orthodontist or the dental surgeon using fixed orthodontic therapy. However, when patients with severity of skeletal malocclusion may require a more comprehensive approach (as in the management of skeletal open bite), then orthognathic surgical intervention procedures are planned, without which only fixed orthodontic therapies would fail hence, surgery and therapy are used in combination for skeletal malocclusion in anterior open bite cases.

4. Dental malocclusion of open bite in a growing patient, such as a young adult, can be treated using certain myofunctional appliances. These appliances need to be worn for a specified period followed then by a short- or long-term retention period with removable orthodontic appliances.

How Does Open Bite Affect Adults?

In adults, an open bite is characterized as a lack of contact between the maxillary and mandibular anterior, whereas the posterior teeth are occluded. The cause of adult open bite may be skeletal issues or jaw positioning. If this is the cause, adult open bites must be treated through surgery. Other alternative treatment options include braces, appliances, or clear aligners. Usually, an adult open bite is treated with the help of the anterior bite plane. This orthodontic appliance prevents the contact of posterior teeth, which helps reduce muscle activity and correct overbite and TMJ conditions.

Conclusion:

Anterior open bite is a dental or skeletal malformation where the anterior tooth does not overlap while biting. This condition can cause functional and esthetic issues. It thus may require simple to complex integrated treatment strategies such as orthodontic, periodontal, and restorative intervention for correcting the bite in specific cases.