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Canine Malocclusion

By Joyce Tai, DVM, MS
angell.org/dentistry
dentistry@angell.org
617-522-7283

May 2024

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Malocclusion of the oral cavity is a common finding noted in dogs and has been reported in 13.7% to 26% of dogs seen.1,2  Puppies as young as 8 weeks of age2 have been identified with malocclusion. As the majority of maxillofacial development occurs within the first 36 after birth, the relationship between the maxilla and mandible continues to change during this time, so close monitoring throughout the first year of life is necessary.

This is an example of a Class 1 and Class 2 where the mandibular right canine is lingually deviated and is the entire mandibular dentition is slightly distally deviated (increased space between mandibular and maxillary incisors).

So, what is malocclusion? Occlusion is the relationship of dentition when the upper and lower jaws contact. It is determined by both the skeletal and dental relationship of the maxilla and mandible. Dental and skeletal occlusion should be symmetrical on the dog’s right and left sides. Maxillary incisors should be just rostral to mandibular incisors so that the coronal tips of the mandibular incisors are actually resting on the palatal (portion of the incisors that face the roof of the mouth) base of the maxillary incisors. Mandibular canines are mesial (rostral in the oral cavity) to the maxillary canines and rest between the diastema of the maxillary third incisor and canine. The premolars are interdigitated, meaning they do not sit in the same transverse plane but are offset so they don’t touch each other when the mouth is closed. Mandibular premolars should be lingual and just rostral to their maxillary counterparts. Lastly, the molars are defined as such so that both mandibular and maxillary molars meet to create a grinding surface. It’s important to note that the maxillary fourth premolar does align with the mandibular first molar, but they do not touch. The mandibular first molar is offset to be palatal to the fourth premolar, so it still acts as a shearing tooth, not a grinding tooth in this occlusion, while contacting the maxillary first molar more caudally for grinding.

Post-orthodontic device to shift mandibular canine rostral and lateral to create an atraumatic occlusion.

Malocclusions are categorized into four different classes. Class 1 malocclusions involve a normal skeletal alignment, but one or multiple teeth are out of alignment. An example is a mesioverted canine or ‘lance tooth’ seen in Shetland Sheep Dogs or ‘base narrow’ canines. A Class 2 malocclusion is described as mandibular distoclusion. Essentially, the teeth of the mandible align more caudally than expected due to a skeletal mismatch in the length of the maxilla and the mandible. Similarly, Class 3 malocclusions have a mandibular mesioclusion where the mandible is longer than expected for the maxilla. It is important to note that it may be the maxilla that is shortened (such as in brachycephalic dogs), but the classification is still based on mandibular position relative to the maxilla. A Class 4 malocclusion shows asymmetry between the left and right sides of either the maxilla or mandible or both and can be described as a ‘wry’ bite where the jaw looks curved to one side. The term ‘wry’ bite is not recommended as it does not indicate how or where the asymmetry lies. Class 4 malocclusion is most commonly seen after trauma to young dogs. It is important to note that one patient can also have multiple malocclusions. While a simultaneous Class 2 and Class 3 cannot exist, a Class 1 and a Class 2 (shown below) or 4 can exist together.

Treatment for malocclusions falls into three general categories. Options include extraction of teeth, endodontics, and orthodontics. Selective extractions can be considered to prevent self-trauma in an occlusion. While the skeletal abnormality may not be addressed, the goal is comfort and function. One should always recheck the occlusion after a tooth of interest is removed. The new occlusion may yield trauma from other dentitions that could not occur due to the inability to close the mouth thoroughly. For puppies with deciduous dentition, some evidence supports the extraction of traumatic deciduous teeth to promote eventual normoclusion of the permanent dentition.3

Endodontics can be considered for cases where a client would like to retain at least some structure of the tooth while limiting or exterminating self-trauma. Most commonly, the endodontic procedure is a crown reduction with vital pulp therapy. Chronic follow-up is necessary to monitor the health of the reduced teeth for continued maturation. Failure to do so can result in abscess formation and necessitate further treatment, such as root canal therapy or extraction. Lastly, orthodontic movement is an option for some cases of malocclusion. Devices can range from passive devices (shown below) to active devices with rubber chains to pull teeth into position. While malocclusion may be a permanent change to a dog’s conformation, many options exist to provide functional, pain-free use of the oral cavity.

References

  1. Berman M, Soltero-Rivera M, Scanlan AJF. Prevalence of Dental and Skeletal Malocclusions in Mesaticephalic and Dolichocephalic Dogs—a Retrospective Study (2015–2018). Journal of Veterinary Dentistry. 2023;40(2):143-153. doi:10.1177/08987564221141826
  2. Hoyer NK, Rawlinson JE. Prevalence of Malocclusion of Deciduous Dentition in Dogs: An Evaluation of 297 Puppies. Journal of Veterinary Dentistry. 2019;36(4):251-256. doi:10.1177/0898756420905136
  3. Herrmann K, Taney K. Assessment of Extractions of Deciduous Mandibular Canine Teeth to Correct Linguoversion Malocclusion in 17 Dogs. Journal of Veterinary Dentistry. 2022;39(3):234-240. doi:10.1177/08987564221099133
  4. Storli SH, Menzies RA, Reiter AM. Assessment of Temporary Crown Extensions to Correct Linguoverted Mandibular Canine Teeth in 72 Client-Owned Dogs (2012-2016). Journal of Veterinary Dentistry. 2018;35(2):103-113. doi:10.1177/0898756418774886
  5. Volker MK, Luskin IR. Management of Mesioverted Maxillary Canine Teeth and Linguoverted Mandibular Canine Teeth. Journal of Veterinary Dentistry. 2016;33(3):170-184. doi:10.1177/0898756416677395
  6. Wiggs RV, Lobprise HB. Veterinary Dentistry, Principles & Practice. Philadelphia: Lippincott-Raven; 2019: 411–437.