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Overbite (Deep Bite, Malocclusion)

What is an overbite?

Overbite or deep bite is a type of malocclusion where there is excessive vertical overlapping of upper dental arch over the lower dental arch. The upper dental arch is larger than the lower dental arch which naturally allows the upper teeth to overlap lower teeth. This overlapping of the lower arch occurs in both horizontal and vertical direction. The term overjet is used for overlapping in the horizontal direction. The vertical overlap is known as overbite. An excessive overbite leads to formation malocclusion termed as deep bite. It is one of the most commonly encountered types of malocclusion with the opposite commonly referred to as an underbite.

Overbite Symptoms

Types

Overbite or more correctly deep bite is generally categorized into two types :

  1. Dental deep bite
  2. Skeletal deep bite

Appearance

Dental deep bite is characterized by absence of any bony malformations in the facial region and when the cause of deep bite is solely teeth related. The dental findings could be representing a complete or partial increase in vertical overlap. It may be limited to the central and lateral incisors in partial cases and may extend covering all posterior teeth in complete deep bites.

The most common features of skeletal deep bite include patients with a horizontal growth pattern. Generally patients exhibiting skeletal deep bite have a reduced facial height. The space between upper and lower teeth is also reduced. Deep bite may also be associated with deep outer sulcus below the lower lip (mentolabial fold) and everted lower lip. Deep bite may cause trauma to the oral mucosa leading to formation of ulcers, tooth sensitivity due to attrition and periodontal problems.

Causes of Overbite

The dental deep bite may be associated with premature loss of posterior teeth or by presence of incompletely erupted molar teeth. The incomplete eruption of molars may be associated with lateral tongue thrust habit – habitual pushing against the front teeth with the tongue. It is generally seen associated with class II malocclusion.

Increased overbite may lead to wear of grinding surfaces of the teeth and excessive wear of the teeth may lead to further increase in overbite. Deep bite may also be associated with upper teeth which are erupted more than their desired level in the dental arch (supra-eruption). Skeletal deep bite is type of malocclusion which is genetically inherited.

It is caused due upward placement or slight rotation of the lower jaw. It may also be associated with upper arch bone(maxilla) placed downwards and inclined forwards leading to excess vertical overlap of lower arch. Both these factors may be present in a few cases.

Overbite Treatment

The diagnosis of deep bite can be made by thorough clinical examination and using dental radiographs (x-rays) such as lateral cephalograms. Study models mimicking the dental arches and finding the cause of the malocclusion is equally important. The treatment can be done by using three approaches :

  1. Removable appliance
  2. Myofunctional appliance
  3. Fixed appliance

The most commonly used removable appliance is the anterior bite plane. It is a flat ledge of acrylic material placed behind upper anterior teeth.
If deep bite is diagnosed in early years of life, myofunctional appliances such as an activator can be used to correct the malocclusion. Fixed orthodontic therapy using arch wire and brackets is also helpful in treating deep bite.

Braces are helpful for children but more invasive measures are needed later in life. Misshapen teeth can be reshaped which may improve the overbite in these cases. Surgery is rarely considered for overbite but involves reshaping the jaw, to shorten its length.

 


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