Advanced Animal Dentistry

Bite Abnormalities in Dogs

Malocclusions (bite abnormalities) are not uncommon in dogs and fall into 4 basic groupings: 

  • Class 1 malocclusion 
  • Class 2 malocclusion 
  • Class 3 malocclusion
  • Class 4 malocclusion
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The normal occlusion of a dog

The “normal” occlusion of a dog.

Class 1 Malocclusions

Class 1 malocclusions occur when individual teeth are in the incorrect position but the jaw lengths are correct. Malocclusion that may fall into this category include: rostral cross-bite, caudal cross-bite, base narrow mandibular canines, ‘lance’ canine teeth, overcrowded and rotated teeth. These may occur in combination with other classes of malocclusion. 
Linguoverted mandibular canines

1. Linguoverted mandibular canine teeth.

Anterior crossbite of incisors in a dog

2. Anterior crossbite of incisors.

Overcrowded premolars in a dog

3. Overcrowded and rotated premolars.

Class 2 Malocclusions

Class 2 malocclusions are commonly known as overbites (i.e. the top jaw is too long or lower jaw is too short). This often results in the mandibular canine teeth (& sometimes the mandibular incisors) impacting into the soft tissue of the palate. This causes pain and discomfort when the mouth is closed and can eventually lead to formation of an oronasal fistula (a hole through the top of the hard palate into the nose) 
Treatment for deciduous (baby) teeth contacting the soft tissue of the palate/maxilla is extraction. For the permanent teeth, orthodontic movement by various methods, height reduction and vital pulpotomy of the mandibular canines or extraction may be treatment options. 

Severe Class 2 Malocclusion in a dog.
Class 2 Malocclusion - an overbite

Class 3 Malocclusions

Class 3 malocclusions are often referred to us underbites (bottom jaw longer than post jaw). In many cases these are purposely bred for e.g. Boxers, Shih-Tzus, Frenchies etc. This does not mean that they cause no problems. These malocclusions may also result in base narrow mandibular canine teeth or trauma to the floor of the mouth or other teeth from the maxillary incisors. Careful examination of the lingual (tongue) side of the mandibular incisors and mandibular canine teeth will commonly show damage from the maxillary incisors and can be treated by extraction or occasionally odontoplasty of the maxillary incisors. 
Class 3 Malocclusion - an underbite
Significant Class 3 Malocclusion in a dog, or underbite.

Class 4 Malocclusions

Class 4 malocclusions are seen less frequently and have often been referred to as ‘wry bites’. This is where one quadrant of the jaws is too long or too short or twisted in compared to the other three. These malocclusions are occasionally development however we most commonly see them secondary to trauma or surgeries where part of the jaw has been removed. Treatment may or may not be required depending on whether the malocclusion results in trauma or discomfort.  
Wry bite in a dog, where the jaws end up "twisted".