The rabbit's teeth grow continually throughout it's lifetime, 1/2 inch or more per month. Therefore, it's important that the teeth are properly aligned to assure continual wear on the tooth surface. The upper incisors should slightly overlap the lower incisors. Mandibular pronathism (misalignment of the teeth) is often referred to as malocclusion, buck or wolf teeth, where the lower incisors have overlapped the upper incisors. In these cases, the teeth may continue to grow excessively and in the worst cases, the teeth can curl around and protrude through the roof of the mouth and out the nose. It may become impossible for the rabbit to eat and it will starve. Less common is the overgrowth of molars which can cause severe tongue or cheek lesions. Malocclusion can occur in any breed of rabbit, but is most often seen in breeds with rounded heads such as Hollands Lops and Netherland Dwarfs. It is not considered ethical to sell these rabbits as pets.
A simpler form of malocclusion is called "butting" or "trap" teeth, where the upper and lower incisors meet or "butt" together and do not properly overlap. Like the more serious forms of malocclusion, butting teeth are a disqualification on the show table. Since many cases of malocclusion are hereditary, any stock producing offspring with misaligned teeth should be removed from the breeding program.
While it is relatively easy to trim the teeth with amall wire cutters (this would need to be done almost weekly), it can become more difficult to get the teeth short enough as the animal ages and the nerve extends farther down the tooth. It may also not be economically feasible for the owner to make frequent trips to the vet. The animal may have difficulties eating and cleaning itself which may lead to the developement of other problems. It is possible for the veterinarian to remove the incisors, and the rabbit can still eat normally.
It's important to regularly check your rabbit's teeth for any signs of problems, since tooth alignment can change rapidly, especially in young rabbits. Due to rapid skull and jaw developement in youing rabbits, teeth can go in or out of alignment, and it is sometimes possible for young rabbits to outgrow malocclusion. Trimming may help crooked teeth grow out straight.
Tooth damage may occur due to the rabbit frequently pulling on the cage wire. In these cases trimming may help the teeth realign. Giving a rabbit hay or some toys can help discourabe wire pulling. Although rabbits don't require a "teething block" for proper dental wear, they do enjoy chewing on a tree branch or block of wood. Avoid cedar, black walnut or any treated woods.
A weekly general health inspection should be performed on each rabbit, including checking for any signs of malocclusion. It's also important to inspect the teeth of any rabbit you are considering for purchase. Since many times a rabbit may show no outward signs of dental problems until it's too late, general care and maintenance of your rabbit can help prevent serious health problems.