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Providing Veterinary Dental Services to Cats & Dogs
in the San Francisco Bay Area

Orthodonture
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Orthodonture is the branch of dentistry concerned with preventing and correcting irregularities of the teeth malocclusions).Some of the more common orthodontic issues we see include the following:
  1. 1. Upper jaw too short (underbite)
  2. 2. Upper jaw too long (overbite)
  3. 3. Lower canines point inward and hit the upper jaw
  4. 4. Upper canine pointing forward (lance canine)
  5. 5. Deciduous (baby) teeth which are not lost on schedule
Malocclusions - Types of Malocclusions
In order to understand what is abnormal, one needs to first understand normal occlusion:
malocclusion
Images in this section copyright © AVDC, used with permission.
malocclusion
The upper incisors are slightly in front of the lower incisors. The lower canine fits perfectly into the space between the upper lateral incisor and the upper canine. The upper and lower premolars alternate with the opposing premolars so that they fit into their respective places on the jaws.
Class II Malocclusion...Mandibular distoclusion
Also known as “overbite”, the mandible (lower jaw) is abnormally relatively shorter than the maxilla (upper jaw). As can be seen, the lower canines do not fit properly into their space between the upper lateral incisor and the upper canine, in fact the “space” or diastema, is too narrow to accept the canine. The premolars are also out of alignment and do not alternate equally as seen above. The lower canines and incisors will, therefore, tend to traumatize the tissues of the maxilla.
malocclusion malocclusion

Mandibular mesioclusion...Class III Malocclusion
Also erroneously known as “underbite” in this condition, the mandible is abnormally relatively longer than the maxilla. The lower canines are impinging on the backsides of the upper lateral incisors and the upper incisors are impinging on the backsides of the lower incisors. This can cause pain to the dog as well as irreversible periodontal disease which could result in loss of the lower incisors. In worst case scenarios, some, if not all of the upper incisors need to be extracted. The relative elongation of the mandible is also reflected in the abnormal spacing of the premolars.
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malocclusion

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Another case of Class III malocclusion showing the 2 lateral lower incisors being forced out of position. The lower canines are also being forced labially (to the outside). Same dog showing the damage being caused to the backsides of the lower incisors by the upper incisors.
Mesioversion of the maxillary canines  
This condition, also known as “lance canine” is seen primarily in Shetland Sheepdogs (Shelties) but also occasionally in cats. The upper canines are directed forward much like a lance would be aimed by a soldier in days of old. This condition requires orthodonture to pull the upper canine back into its normal position and then move the lower canine to the inside so it fits between the upper lateral incisor and the upper canine.
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malocclusion image

Malocclusions in Cats  
Cats can have retained deciduous teeth and lance canines just like dogs but these problems are rare. A more common problem, in my experience, is the malocclusion which involves the upper 4th premolar impinging on the gingiva of its mate on the mandible (lower jaw)...the mandibular molar.
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The point or “cusp” of the upper tooth has traumatized the periodontal tissue of the lower molar to the point where the bony support of the lower tooth is jeopardized. In this case, treatment involved blunting the cusp of the upper tooth to minimize further trauma. The upper premolar has traumatized the lower gingiva to the point that a granuloma has formed. Extraction of both the upper and lower teeth resolved the problem immediately. Occlusal trauma has created an even bigger granuloma. Both upper and lower teeth were extracted and the granuloma surgically removed.
     
Problems with deciduous teeth  
Retention of deciduous (baby) teeth in puppies is a common problem. It is more of a problem in small breeds such as Miniature and Toy Poodles, Yorkshire Terriers, Pomeranians, and Chihuahuas. The rule of thumb is that if two teeth are trying to occupy the same spot, the deciduous tooth must be extracted. Time is of the essence because if the retained deciduous teeth force the permanent teeth out of position the permanent tooth might require orthodonture to avoid a permanent malocclusion.
deciduous malocclusion image deciduous malocclusion image deciduous malocclusion image
     
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Right upper deciduous canine has not been lost and therefore is forcing the permanent canine forward. Deciduous canine needs extraction immediately. Lower deciduous canines are forcing permanent canines inward where they will traumatize the hard palate. Deciduous teeth need to be extracted immediately and the permanent canines moved outward into a normal position. This dog only has 4 permanent lower incisors (should be 6) permanent lower. Retained upper deciduous canines are pushing the permanent canines forward. Immediate extraction is necessary.
Base Narrow Lower Canines    
The correct name for this fairly common in dogs is linguoversion of the mandibular canines. It is often, but not always, caused by retained lower deciduous canines. In most cases the canines cause trauma to the hard palate. In extreme cases, the point of the lower canine can penetrate through the hard palate into the nasal cavity. Treatment involves one of the following: (1) orthodonture to move the canines into normal occlusion, (2) crown amputation to eliminate any contact with the upper gingiva or palate, or (3) extraction of the tooth.
base narrow image base narrow lower canine image base narrow lower canine image
This is fairly mild linguoversion but even here the lower canine is traumatizing the upper gingiva. This defect, if allowed to continue could endanger the upper canine to say nothing of the discomfort it is causing the dog. The lower canine was moved, orthodontically, using an inclined plane which was fabricated out of a flowable acrylic. It was left on for 3 weeks and resulted in normal occlusion.
     
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