Dental Disease in Rabbits

Many people think of rabbits as rodents, but they are actually lagomorphs (a group of animals including rabbits, hares, and pikas). Both rodents and lagomorphs have open-rooted teeth (continuously growing throughout life); however, rabbits and rodents differ in the teeth that continuously grow. Rabbits have easily visible incisors (front teeth) plus molars in the back of the mouth for grinding and chewing.

Unlike rodents, however, lagomorphs have two small, tube-shaped incisors (peg teeth) behind the large upper incisors. Since the teeth continuously grow, the upper teeth must meet the lower teeth to allow for proper wearing of tooth surfaces, preventing overgrowth. All teeth must meet and wear at the same rate as they are growing, or problems arise.

"Lagomorphs have two small, tube-shaped incisors (peg teeth) behind the large upper incisors."

rabbits-dental_disease-1Malocclusion (imperfect positioning or meeting of the teeth when the jaws are closed), with resultant improper tooth wear, and overgrowth of the incisors or molars, can occur in rabbits.

Overgrown points or sharp spikes that form on the edges of teeth may cut and badly damage the tongue, cheeks, or gums. Overgrown lower molars may form a bridge over and entrap the tongue. Overgrown molars may hit each other in the back of the mouth, thereby preventing the front of the mouth from closing completely and changing the way the incisors meet. As a result, incisors do not wear down properly and can overgrow.

Overgrown upper and lower molars in the back of the mouth hit each other as the rabbit tries to close its mouth. As these teeth continue to grow and are not worn down, they become impacted in the upper and lower jaws, just like impacted wisdom teeth in people. All of this can lead to pain when chewing, the development of sores and abscesses in the mouth, difficulty eating, drooling, pawing at the mouth, problems grooming, and weight loss.

"Malocclusion with resultant improper tooth wear, and overgrowth of the incisors or molars, can occur in rabbits."

Misshapen incisors and malocclusion of the incisors will sometimes cause these front teeth to protrude out of the mouth, grow at an angle to each other, curl back into the mouth, curl sideways, or take on other problematic positions.

Rabbit teeth normally grow at a rate of approximately 1 cm each month, and in the case of an unopposed incisor, growth can be as much as 1 mm per day.

 

Why do these teeth grow abnormally?

There are likely many causes of tooth elongation, malocclusion, or improper growth and wear rates. A significant contributing factor is a diet lacking in enough roughage or fiber to promote normal tooth wear. Wild rabbits grind down their teeth all day by chewing constantly on grass. Pet rabbits may eat some hay, but they often eat a great deal of crumbly rabbit pellets that do not help wear down the teeth. Some pet rabbits do not eat hay at all.

"A significant contributing factor is a diet lacking in enough roughage or fiber to promote normal tooth wear."

In addition to improper diet, malocclusion may also have a hereditary or congenital component especially in young dwarf or lop-eared rabbits. These breeds seem to be over-represented when it comes to dental disease in rabbits.

There are also theories that indoor rabbits that are not exposed to ultraviolet light required to form vitamin D in the skin (which enables absorption of calcium from the diet), do not have properly formed teeth due to a lack of calcium. Therefore, genetics, environment, and diet all potentially contribute to the development of dental disease in rabbits.

 

What can be done about this?

To minimize the development of dental problems, your rabbit should be fed a diet consisting mainly of high-fiber hay, with smaller amounts of pellets and fresh produce, so that she chews her food constantly and wears her teeth down in the process.

Rabbits with dental problems need regular veterinary care. Overgrown incisors should be shortened by a veterinarian familiar with rabbits; this usually needs to be done regularly, every few weeks to months, as the teeth continue growing. Veterinarians used to clip rabbits' teeth with nail clippers, but this is no longer recommended, as trimming teeth this way often damages the teeth or gums.

"Rabbits with dental problems need regular veterinary care."

Most veterinarians who regularly treat rabbits now use dental burrs on dental drills to file down the incisors and molars, often under anesthesia. Treating poorly aligned molar teeth can be challenging but is part of routine care for a well-trained rabbit veterinarian. If a rabbit is having recurrent dental problems, one long-term solution is to remove the affected upper and lower incisors or the affected molars to prevent the need for repeated future teeth filing. This procedure may be simple or complex, depending on the number of teeth affected, their location in the mouth, and whether infection is present. Although teeth extraction sounds drastic, it is without doubt the best long-term solution to the problem if chronic overgrowth occurs, and is the only solution if teeth are infected and their roots are abscessed.

Following tooth filing or extractions, it is very important to get the rabbit eating immediately, to promote appropriate wearing of the existing teeth and to keep the gastrointestinal tract functioning properly. Veterinarians will routinely teach owners to syringe feed their rabbits commercially available powdered formulas mixed with water for rabbits that are not eating. Annual veterinary check-ups are crucial for all rabbits to identify any developing dental problems and prevent them from progressing.

This client information sheet is based on material written by: Laurie Hess, DVM; Rick Axelson, DVM

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