The relationship between the teeth of the maxilla (upper jaw) and mandible (lower jaw) can be characterized as either normal occlusion or malocclusion.
In cats and dogs with normal occlusion, well-aligned mandibular teeth engage in an interlocking pattern with well-aligned maxillary teeth. The interaction between the teeth of the mandible and maxilla allows for catching prey, picking up and carrying food, chewing, and biting. These actions should not result in any trauma.
The mandible is hinged to the maxilla at the temporomandibular joint (TMJ). The mandible is moved by masticatory muscles against the maxilla.
Misaligned teeth, jaws, or temporomandibular joint can cause malocclusion, which may result in oral disease, pain, and loss of function ranging from mild to debilitating.
Malocclusion can be something a pet was born with (congenital), something that occurred as the pet was growing (developmental), or acquired, usually due to trauma. Skeletal malocclusion is due to abnormalities of the jaws (either in length or symmetry) or temporomandibular joint, while dental malocclusion is caused by the abnormal position of one or more teeth in otherwise-normal jaws.
Consequences of malocclusion
While the direct result may be mild tooth attrition with associated various degrees of discomfort, the malocclusion can also create ideal conditions for development of oral disease. For example, a jaw that is too short can result in crowding of teeth, which predisposes to periodontal disease.
Major malocclusions can result in significant oral trauma. For example, when mandibular canine teeth do not align properly with the maxilla, they can cause trauma to the palate (roof of the mouth). In severe cases, this trauma can even penetrate the palate, causing an oro-nasal fistula, a communication between the mouth and the nasal
Diagnosis of malocclusion
Malocclusions can be classified based on oral examination, but oral diagnostics, including dental radiographs and probing are required for treatment planning. When the malocclusion originates in the temporomandibular joint area, advanced imaging such as computed tomography (CT or CAT scan) may be needed to plan treatment.
Any painful condition caused by malocclusion, or any malocclusion that causes oral trauma should be treated.
There are several ways to address malocclusion. Depending on the type of problem, a variety of orthodontic treatments to move or align teeth, or surgical treatment to reshape or extract teeth may be needed.