Malocclusion is unfortunately a very common disease and one many owners misunderstand. It is extremely painful for the chinchilla and close observation of your chinchillas can help to catch symptoms early.
There are several causes thought to be behind the disease. Among them are genetics, poor diet/nutrition, lack of calcium and vitamin C, injury, lack of items to chew on (toys, wood, etc.) for the front teeth, and lack of sufficient fiber (hay) to help keep the back teeth ground down. Because the disease can be genetically carried, it is recommended that no chinchilla with known malocclusion ever be bred.
Symptoms of malocclusion can include:
- Decreased food intake
- Eyes that look wet (often mistaken for an eye infection)
- Drool, creating a wet chin/chest area
- Weight loss
- Audible, frequent tooth grinding
- Pawing at the mouth, as if in pain
When the molar crowns overgrow, they can grow outward and/or curve inward. Upper molar crowns tend to curve outwards and the lower molars tend to grow inwards. Outward growth can cause tooth spurs, which will cut into and injure the cheek tissue, creating pain and likely infection. Inward growth can create sharp points that cut or even trap the tongue. Both of these make eating nearly impossible and terribly painful.
Not only can the teeth themselves overgrow, but the roots of the teeth as well. The roots can literally grow upwards into the eye sockets, or through the jaw bone. Often at this point, they can be felt along the lower jaw as bumps using your fingertips.
Malocclusion is usually a painful, often fatal condition. Early diagnosis can buy some time to trim the teeth themselves, but cannot correct root overgrowth. At the first sign of malocclusion, your chinchilla should be seen by an experienced exotic veterinarian. Unfortunately most cases are quite advanced by the time symptoms present themselves, making treatment often difficult.
Included below are some radiographs (x-rays) of a normal chinchilla and a severely maloccluded chinchilla. Normal radiographs are of my personal chinchilla (Praline) taken 3/5/04 and the maloccluded radiographs are used with permission, taken by the same veterinarian in February, 2004. Please note that the radiographs for Praline are a bit dark, but are clear enough to denote the differences.
You can easily see the differences in this view. A normal chinchilla should have a nice straight alignment of the back teeth with little to no curving of the teeth or roots. The roots should be contained within the jaw bones, not protruding.
The maloccluded chinchilla has clearly visible overgrowth of both the molars themselves and the roots. The roots appear to be protruding into the eye sockets and out from the lower jaw. It also appears that the bottom incisor has been trimmed, probably due to overgrowth as well.
In the normal view, you can see that the roots are nicely contained within the proper areas. In the maloccluded view, you can see the teeth growing outside of the jaw itself.
In the normal view, you can clearly make out the eye sockets, a straight line between top and bottom back teeth, and no visible overgrowth of the roots.
In the maloccluded view, the eye sockets are nearly completely blocked from sight by overgrowth of the tooth roots, no line is visible to distinguish top jaw from bottom jaw, and the view of the jaw is barely visible due to root overgrowth.
As you can see, left untreated this condition can be very painful to the chinchilla and it will eventually starve to death. Sometimes the quality of life can be improved by trimming the teeth and giving pain medication, but not always. Once the roots overgrow to the degree pictured, a chinchilla is in constant pain and you, as a loving guardian, should consider the quality of the chinchilla's life and maybe discuss potential euthanasia with your veterinarian.
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Links to the article are allowed. No permission is necessary to do so. Pictures are not to be used elsewhere, however I am happy to email the original, high resolution images of the normal chinchilla to a veterinarian for reference if needed. Contact firstname.lastname@example.org.
Here is a link to a fantastic chinchilla dental chart for your vet: