Improper dental wear and disease in rabbits can result in overgrown teeth. All ages and breeds of rabbits can be affected, though the skull shape of certain rabbit breeds, like the Netherland Dwarf and Holland Lop¹, can cause crowding of the molars and misalignment of the incisors. This condition is common in pet rabbits that lack an appropriate diet, have a calcium and vitamin D imbalance, or have injured teeth and jaws. If overgrown teeth are not maintained regularly, the rabbit may have difficulty eating, lose weight, and develop other ailments, such as gastrointestinal stasis secondary to insufficient fibrous material in the diet.
What Is the Normal Dental Anatomy of a Rabbit?
Adult rabbits have a total of 28 teeth. There are two top incisors, two bottom incisors, and a second pair of smaller incisors, known as peg teeth, located directly behind the top incisors. They also have 10 premolars and 12 molars, collectively known as the cheek teeth. There are no canine teeth¹. Instead, a space called the diastema separates the incisors from the cheek teeth.
All teeth are open rooted and grow continuously, which differs from rodents¹. The growth rate of the upper and lower incisors is about 1.9 mm and 2.2 mm per week, respectively¹. The shape of the teeth undergoes a continuous process of growth and wear, which is affected by the quality of a rabbit’s diet.
Rabbit incisors have a chisel-like appearance, and they regularly grind together to help keep the tips in cutting shape. In a closed and relaxed jaw, the edges of the bottom incisors rest just behind the top incisors, meeting with the peg teeth¹. The upper jaw (maxilla) is wider than the lower jaw (mandible), and only one side of the mouth grinds food at a time.
What Are the Signs of Overgrown Teeth in Rabbits?
Misalignment of the teeth, known as malocclusion, can cause the teeth to overgrow because the normal wear keeping them in shape is not occurring. When the teeth elongate, the top incisors usually curl back into the mouth, the lower incisors tend to extend upward and forward, and the small peg teeth grow down and outward. The bottom incisors may protrude out of the mouth as they lengthen. Elongated premolars and molars¹ can form sharp spurs or points, which may lacerate the sensitive tissues of the oral cavity and cause painful sores on the tongue, gums, and inside of the cheeks.
Common signs of overgrown teeth¹ include:
Infection of the tooth root can spread to the surrounding bone and soft tissues, such as the gingiva. A rabbit dental abscess consists of thick purulent material encased in a capsule.
What Are the Causes of Overgrown Teeth?
The causes of dental elongation can either be congenital or acquired. Congenital conditions, which are present at birth, include malformation of the teeth and jaw, such as an overbite or underbite. Acquired conditions can occur from injury or trauma, inappropriate diet or nutrition, foreign body, metabolic bone disease (MBD), or cancer. For pet rabbits, insufficient dental wear from a lack of a fibrous diet¹ is often a common cause of the development of overgrown teeth. Wild rabbits have more opportunities to eat roughage and grasses, promoting normal wear of their dentition. Rabbits that chew and pull on their wire enclosures may inadvertently misalign the incisors, leading to overgrowth. Lack of unfiltered, natural sunlight and an inappropriate diet may cause low levels of vitamin D in the body¹, resulting in MBD and thinning of the alveolar bone. Vitamin D is required for calcium absorption.
How Is It Diagnosed?
Your veterinarian will perform a thorough physical examination, paying attention to your rabbit’s face, jaws, and teeth. The exam involves feeling the upper and lower jaws for signs of swelling, unevenness, and pain, which may indicate dental disease. The vet will also evaluate the incisors for their bite (occlusion), length, and appearance. Assessing the cheek teeth involves noting the arrangement, shape, size, and length of the premolars and molars. Your veterinarian may use an otoscope to examine the mouth, but a more detailed exam requires the rabbit to be sedated or anesthetized. The anatomy of a rabbit’s oral cavity makes examination of the cheek teeth difficult, as the cheeks and tongue tend to obscure the dental arcades, and the space itself is relatively small¹.
Radiographs, or X-rays, of your rabbit’s skull, can show the extent of dental disease. Advanced diagnostics, such as computed tomography or ultrasound, can be helpful in the further evaluation of the soft tissues, teeth, and bone. Contrast studies are useful to assess the patency of the tear ducts, which may become obstructed by the overgrown roots of the top incisors. A blocked tear duct leads to impaired tear drainage, which can cause wetness and matting under the eye. Abscesses may be sampled for culture and sensitivity testing in order for the vet to prescribe the most effective antibiotic therapy to treat the infection.
How Do I Care for a Rabbit With Overgrown Teeth?
Rabbits with overgrown teeth may have limited food intake or may not eat at all. Supporting the rabbit through this stage is critical and typically consists of fluid therapy, usage of an assisted recovery formula such as Oxbow Critical Care¹ or Emeraid Herbivore¹, and pain management. Correcting overgrown teeth requires sedation or anesthesia of the rabbit because the procedure can be stressful. Dental equipment, such as a cutting wheel or dental bur with a drill, will cut elongated incisors and smooth dental spurs and points. Nail clippers, wire cutters, or trimmers are not ideal for teeth because they can shatter or fracture them, resulting in sharp points, pain, and infection.
Overgrown incisors and cheek teeth need to be re-evaluated and trimmed approximately every 4–6 weeks¹, depending upon their rate of growth. In cases of chronic dental disease, extraction of the incisors or affected cheek teeth can help improve the rabbit’s quality of life. Monitoring the rabbit’s weight, body condition, and feeding habits are essential because dental disease tends to be progressive. Finding and correcting problems early may stop or slow the advancement of the disease. With early intervention, the prognosis may be good. However, the outcome may be more guarded if infection and abscessation are present.
How Do I Prevent Overgrown Teeth?
Preventing dental disease in rabbits includes feeding them a nutritionally complete and appropriate diet. Grass hay, such as timothy or oat hay, comprises around 70% of a rabbit’s diet and should be available at all times. Oxbow Animal Health¹ has a variety of grass hays to mix and match for enrichment activities. Alfalfa has a higher nutritional value than grass hay, which may lead to obesity or the development of bladder stones in healthy adult rabbits. Therefore, it is only recommended for growing, pregnant, nursing, or ill rabbits. High-quality timothy hay pellets should total about 20% of the diet, and dark leafy green vegetables can be included at about 10%. Fresh, clean water should be available at all times. Regular veterinary care, including oral exams, can detect and correct any dental issues early should they arise.
Tips for Keeping Your Rabbit Safe
Conclusion
Rabbits’ teeth grow constantly and are naturally worn down by the abrasive, fibrous material in their diet. A lack of roughage can lead to overgrown teeth. Other conditions, such as malformed teeth or injury to the jaws, can misalign dentition, resulting in a lack of wear and overgrowth. Feeding your rabbit a diet high in fiber and providing them with regular veterinary care can help prevent overgrown teeth.
Featured Image Credit: Thurid_with_th, Shutterstock
