Name that bite: Recognizing canine and feline malocclusions

A malocclusion is any deviation from the normal occlusion. In a normal occlusion of dogs and cats, the maxillary incisors overlap buccal to the mandibular incisors, the mandibular canine sits between the maxillary third incisor and maxillary canine, the maxillary and mandibular premolars interdigitate in a pinking scissor bite, and the maxillary fourth premolars sit buccal to the mandibular molar.

Malocclusions are treated when they cause any type of trauma whether gingival, mucosal, or tooth to tooth. The rule of thumb is that every patient has a right to a comfortable bite. Malocclusions are generally not treated for cosmetic purposes, especially in breeding or showing animals.

Malocclusions are often inheritable, and these dogs should not be bred. There is no sex predilection. Malocclusions are classified pertaining to the teeth, the jaw position, or both.

MAL1
Class 1 malocclusion is a neutroclusion, meaning that the jaws are in normal relation to each other with one or a few teeth being out of place. This is broken down into further descriptions. A class 1 malocclusion is a dental malocclusion, not a skeletal malocclusion.

• MAL1/BV: Buccoversion- a tooth (or teeth) displaced in a buccal or cheek direction.
• MAL1/DV: Distoversion-a tooth (or teeth) displaced in a distal or away from midline direction.
• MAL1/LABV: Labioversion- a tooth (or teeth) displaced in a labial or towards the lip direction.
• MAL1/LV: Linguoversion- a tooth (or teeth) displaced in a lingual or towards the tongue direction.

Base narrow canines are an example of linguoversed mandibular canines. The mandibular canine can contact the hard palate, causing pain and discomfort. These teeth may be crown reduced with a vital pulp therapy, orthodontically moved with an incline plane, crown lengthened or extracted. Ball therapy may be attempted to move the teeth outward if the patient is young. If the mandibular canines are only slightly maloccluded, a gingivoplasty can be performed on the maxillary gingiva between the third incisor and canine tooth to make more room for the lower canine to fit.
• MAL1/MV: Mesioversion- a tooth (or teeth) displaced in a mesio or towards the midline direction. This is often called a lance tooth. It’s often the maxillary canine tooth displaced in a mesial direction and is common in collies and Shetland sheepdogs. A mesioversed canine can cause crowding with the third incisors and periodontal disease at that location is common if left untreated. Mesioversed canines can be extracted or orthodontically moved with a button and masel chain.
• MAL1/PV: Palatoversion- a tooth (or teeth) displaced in a palatal or towards the palate direction.

Crossbite (CB): One or more of the mandibular teeth are displaced in a buccal or labial direction.
• Caudal Crossbite (CB/C): One or more of the mandibular premolars or molars is displaced in a buccal direction sitting buccal to the maxillary tooth. Collies, shelties, and sighthounds are common breeds to have a caudal crossbite. Treatment isn’t needed unless there are traumatic contacts and then extraction is often the treatment of choice.
• Rostral Crossbite (CB/R): One or more of the mandibular incisors are displaced labially, sitting labial to the maxillary incisors. The offending teeth may be shortened with odontoplasty and sealed with dentin bonding if trauma is occurring.

Class 1 malocclusions are treated if there is trauma to the surrounding tissues including other teeth, gingiva, palatal, or mucosa. Crowded teeth, or malaligned teeth, may predispose a patient to periodontal disease. Interceptive orthodontics is the extraction of maloccluded deciduous teeth. The goal is for the permanent dentition to erupt in its normal position. Extraction of maloccluded permanent dentition causing trauma is a very common treatment option. Orthodontic movement is an option for some patients and involves multiple procedures. Crown reduction with vital pulp therapy, or dentin bonding, is another treatment option to prevent or treat traumatic contacts.

MAL2
Class 2 malocclusion is when the lower jaw is short in relation to the upper jaw, or mandibular distoclusion. In the case where the deciduous teeth are causing bite interlock where they have punctured the soft tissues and are now “stuck”, the deciduous teeth can be carefully extracted with the thought that the short jaws would unlock and potentially grow to normal lengths.
This should be done as early as possible to allow the jaws to grow as normally as possible.
The permanent teeth should be monitored regularly for their growth path. If the permanent mandibular teeth are causing trauma, the canines can be crown reduced with vital pulp therapy. Orthodontic movement with an incline plane is a possible treatment choice if the mandibular canine teeth are not traumatizing the palate. The mandibular incisors may need to be extracted if they are traumatizing the palate.

MAL3
Class 3 malocclusion is when the lower jaw is long in relation to the upper jaw, or mandibular mesioclusion. Brachycephalic breeds such as bulldogs, boxers, Boston terriers, and pugs normally have a class 3 malocclusion. This doesn’t mean that their bite is “normal” and doesn’t need intervention. If the malocclusion is not causing any trauma, then treatment or intervention is not necessary. If the maxillary incisors are causing trauma to the gingiva, lingual to the mandibular incisors and/or canines, they should be either shortened with odontoplasty and dentin bonding or extracted if shortening wouldn’t resolve the trauma. Maxillary teeth can also cause attrition of the mandibular teeth. Any tooth-to-tooth contact should be corrected as well. A class 3 malocclusion can occur with both deciduous and permanent dentition.

MAL4
Class 4 malocclusion is skeletal asymmetry in a caudoventral, left to right (side to side), or dorsoventral direction. This malocclusion used to be called a wry bite.

• MAL4/DV: Known as skeletal asymmetry in a dorsoventral direction. This is when there is an open bite creating an abnormal space between the maxilla and mandible.
• MAL4/RC: Known as skeletal asymmetry in a rostrocaudal direction. This is when the maxilla and mandible are in normal relation on one side and either too short (distoversed) or too long (mesioversed) on the opposite side.
• MAL4/STS: Known as skeletal asymmetry in a side-to-side direction. This is when the middle of the mandible and the middle of the maxilla do not align.

A class 4 malocclusion requires treatment such as extraction or crown reduction if there is trauma.