What are Buck Teeth?

April 09, 2020

  

Buck teeth refers to the condition where the upper stick forward out of the mouth. In medical terms, this is called an increased overjet. The horizontal distance between the upper central incisors and the lower central incisors is termed as an overjet. The normal overjet ranges between 2-3 mm. Buck teeth is a term that is used when this horizontal distance increases beyond 3mm.

What causes an increased overjet?

The way the upper and lower teeth are aligned with each other is called occlusion. When teeth are not intercuspated in the ideal position, it is called malocclusion. These can be of three types.

A Class-I malocclusion is when the mesiobuccal cusp of the first maxillary molar falls in the mesiobuccal groove of the mandibular first molar. An increased overjet is possible, but less common in this form of malocclusion.

In Class-II malocclusion, the mesiobuccal cusp of the maxillary first molar lies ahead of the mesiobuccal groove of the mandibular first molar. This causes an overall shift of the teeth more anteriorly than the normal range. But, Class-II malocclusion has two subtypes owing to the positioning of the maxillary central incisors. If the maxillary central incisors are proclined, it is called Class-II Div 1 type. If they are retroclined, it is called a Class-II Div 2 type.

In the Class-II Div 1 type, because of the proclination of the maxillary central incisors, the horizontal distance from the mandibular central incisor increases. Thus, this form of malocclusion sees the maximum intensity of buck teeth.

In Class-III malocclusion, the mesiobuccal cusp of the first molar falls in between the mandibular first and second molar. Unlike the Class-I and Class-II malocclusions, in Class-III cases the mandible protrudes ahead of the maxilla. Hence, the overjet does increase but because of the mandibular incisors being placed forward than the maxillary counterparts, such a condition is called a negative overjet.

A hyperactive lower lip can also recline the lower incisors. Moreover, in a attempt to achieve an oral seal, the lower lips might further procline the maxillary incisors in Class-II Div 1 cases.

Thumb sucking habit if persistent for 6 hours a day, can increase the overjet in an asymmetrical fashion. In cases of periodontitis, the overgrowth of gingival tissues can drift the maxillary incisors labially, thereby increasing the overjet. Unilateral premature loss of mandibular deciduous molars or mandibular deciduous canine can predispose to an increased overjet.

How harmful can an increased overjet be?

An increased overjet doubles the chance of trauma in children. An Overjet of 6mm is highly vulnerable to orofacial trauma. Males are usually at a greater risk in such cases. Several cases of a child being teased and tortured because of having buck teeth have been reported. Psychologically, buck teeth can have a huge impact on an individual's social well being.

Can an increased overjet (buck teeth) be corrected?

An increased overjet can be corrected by various means. There are various school of thoughts  as to when the treatment for overjet should begin. Some clinicians suggest that it is apt to wait for the permanent dentition to erupt before carrying out any treatment. Some suggest an early intervention is favourable as it reduces the chances of orofacial trauma and also reduced the psychological impact of having buck teeth. However, clinical trials have shown that there is a minimal difference in trauma cases and the earlier start to the treatment of overjet. A third view is that treatment should begin during the late dentition period. Orthodontic appliances delivered during this period has shown a lot more beneficial.

The most favourable treatment modality is an orthodontic approach wherein functional appliances like Herbst appliance, Twin Block appliance or Frankel appliance can be used. While the Herbst appliance is more popular in North America, the Twin Block appliance is more preferred in the United Kingdom. These appliances can effectively move the mandible downwards & forwards, retrocline the upper incisors, distalize the molars and increase the lower facial height.

Some overjet problems are corrected by reshaping the teeth in a way that the lower anterior teeth move forward to contact the upper anterior teeth. This approach is most often used by prosthodontist and is termed as closure of the vertical dimension of occlusion. Restorative techniques often include splinting the incisors to the teeth that are in proper intercuspation. Surgical approach includes moving the maxilla backwards or the mandible forwards in combination with a certain degree of osteotomy.

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