09/05/2026
WARNING!!! Very long educational post!
One thing that I cannot stress enough is for rabbit owners to check the rabbits teeth for malocclusion. Malocclusion is the misalignment of the upper and lower incisors, and can also be a misalignment of the molars and premolars. If the molars and premolars are misaligned, then they cannot wear evenly; this leads to something called molar spurs, where the upper molars flare outward toward the cheeks, and the lower molars flare inward toward the tongue. This is very painful for the rabbit and can lead to bleeding and infection. Malocclusion of the incisors is much easier to see. Rabbits have six incisors: four teeth on the top (two large teeth and two little peg teeth behind them), and two teeth on the bottom. Rabbits have 28 teeth in total!
There are four different types of malocclusion of the incisors. There is Congenital Skeletal Malocclusion, primarily presenting as Mandibular Prognathism; this is an inherited type of malocclusion where the lower incisors grow in front of the upper incisors, due to the fact that the lower jaw (mandible) is structurally too long or that the upper jaw (maxilla) is structurally too short. Studies show that this is caused by a recessive gene, so rabbits can pass it to their offspring without showing any signs of malocclusion themselves.
Secondly, there is Acquired Dental Disease (ADD), or more specifically, Acquired Functional Malocclusion. This type can be caused by an underlying molar or cheek teeth malocclusion. As a result, the rabbit cannot close his mouth completely. This posture shifts the upper and lower incisors so they no longer touch. This means they can no longer grind each other down and therefore begin to overgrow.
Thirdly, Atraumatic Appositional Shift (Transverse Deviation / Crossbite). In this form of malocclusion, the jaw shifts sideways causing the crossbite, and then the overgrowth of the teeth. It is heavily genetic, and two normal-looking rabbits can pass it to their offspring because it is recessive. Other environmental factors can in rare cases also cause this type of malocclusion.
Lastly, there is Traumatic Malocclusion. This type occurs after an injury to the face or mouth. The doe pictured below is an example of Traumatic Malocclusion from a cage biting incident. In the end, the root cause matters. If a rabbit develops malocclusion from an injury, it's an unfortunate accident. But if it is genetic, it needs to be avoided like the plague. It should absolutely disqualify that rabbit from a breeding program, not only is it incredibly painful for the animal, but it is also an automatic show DQ.