Dental Disease In Rabbits: A Dentistry Expert's Guide
Dental disease is a common and serious problem in pet rabbits. Oral health in rabbits is essential as, unlike cats and dogs, their teeth are used to grind down food prior to swallowing it. Eating food that hasn’t been properly processed can cause serious gastrointestinal problems (known as colic). Rabbits’ teeth grow constantly throughout their lifetime, and if they are not worn-down during chewing, the tooth roots can be pushed deeper into the jaws. This can lead to the formation of abscesses in the bone and soft tissues, as well as preventing the rabbit from eating properly.
Under the umbrella of dental disease, we encounter several conditions such as malocclusions (misalignment of the teeth), fractured teeth, periodontal (gum) disease, and dental abscesses. We've turned to Dr. Jose Carlos Almansa Ruiz, a recognised expert in the field of veterinary dentistry, to tell us a bit more about the oral cavity of rabbits, the most common problems and how to prevent them.
- Rabbits’ teeth grow continuously throughout their lives, at a rate of approximately 2mm per week.[1]
- Rabbits have a total of 28 teeth, but unlike cats and dogs, this does not include canine (fang) teeth.
- Rabbits have six incisor teeth used to cut food – two large incisors sit at the front of the upper and lower jaws, with two tiny additional incisors sitting behind the others in the top jaw – these are known as peg teeth.
- A rabbit’s molars (cheek teeth) are used for chewing and grinding food, and have hard ridges of enamel on the tips to help perform this.
- The part of the jaw between the incisors and the molars has no teeth, and is known as the diastema.
- Rabbits are thought to have evolved from a mammal related to the ancestor of the modern horse – although they look very different on the outside, rabbits and horses actually have very similar jaw anatomy and chewing patterns.[2]
- Rabbits shed their baby incisor teeth while still in the womb of their mum.
It is extremely difficult to see a rabbit’s teeth from the outside, even for a trained vet or nurse. Lifting the lips gently can reveal the front (incisor) teeth, but this is only a small part of the story. At the practice, the vet or nurse will use an illuminated tool called an otoscope to examine your rabbit’s mouth. In a healthy mouth:
- The incisors (front teeth) should fit together, with a curved shape due to their normal wear.
- The normal colour for the teeth is ivory white.
- The gums should be pink in colour, with no signs of bleeding or infection.
- The molars (cheek teeth) have an angled chewing edge, created through the action of the top and bottom rows (arcades) grinding against each other. during chewing – the upper arcades should mirror the lower arcades.
- All the soft tissue surfaces inside your rabbits' mouth should have a nice pink appearance, with no growths or ulcers.
- Reduced appetite or picky eating
- Anorexia (refusing food altogether)
- Salivating more than usual
- Front teeth that are obviously misaligned, or protruding through the lips
- Lumps on the bottom of the jawline
- Eyes becoming weepy or bulging
- Discharge from the nostrils
- Any swellings on the face
- Lack of grooming/unkept coat
Spurs/spikes or enamel points
Primary incisor malocclusion
Malocclusion means that the teeth are misaligned, so the top and bottom teeth do not line up correctly when the mouth is closed. Rabbits with abnormal incisor contact are not able to cut and process food normally. Malocclusion is most commonly seen in rabbits under a year old, and mostly in dwarf-like breeds[4]. Trauma, such as the fracture of one of the incisor crowns, can result in the opposite tooth growing in the wrong direction and, potentially, damaging the surrounding healthy teeth. These teeth, if left untreated, can then damage the soft tissues. If teeth become too long due to lack of appropriate wear, they can be treated by a vet – it is important the right equipment is used to avoid the teeth fracturing or becoming more damaged.
In some circumstances, the regular cutting of these teeth does not resolve the problem, and removal of the upper and lower incisor teeth may be appropriate. It is very important to evaluate the cheek teeth in these rabbits, as malocclusion of the front teeth may be related to a problem of the cheek teeth.
Cheek tooth problems
Rabbits fed mostly a commercial diet (pellets) do not wear teeth down at the right rate, as this food does not require a large amount of chewing. The pressure created between the top and bottom cheek teeth affects the germ tissue that generates new root tissue; this pressure causes a reduction in the growth of these teeth, sometimes slowing to only an eighth of the normal rate! The height of the cheek teeth will increase to the point that the mouth will be kept “open”, causing a secondary malocclusion of the incisors. The roots of the cheek teeth will become more curved, further reducing wear of the teeth. Eventually, this leads to formation of enamel spikes or spurs that cause ulceration of the inside of the cheeks and tongue.
The growth of the cheek teeth will eventually stop altogether, and the root can fuse into the surrounding bone. The roots can cause several other problems, including blocking the tear ducts, and causing abscesses in the soft tissues, eye socket and the sinuses/nasal passages.
Poor diet
If the diet is too low in fibre, such as a pellet only diet, this will not be sufficient to wear down the rabbit’s teeth. The teeth quickly grow too long, causing them to meet the opposing teeth in an abnormal position. This further prevents them wearing down properly, causing uneven wear and sharp spurs.
85% of a rabbit’s diet should be hay or grass, allowing them to chew almost constantly through the day. The remaining parts should be 10% leafy green vegetables and just 5% pellets or nuggets to ensure they get all essential vitamins and minerals.
Genetics
Over-long incisors can be seen on examination or may even be spotted at home if they are extending past the lips. Rabbit’s molars (cheek teeth) are impossible to see from the outside. A special tool called an otoscope can be used by your vet to look at the cheek teeth, but even then, it is impossible to get a full view. The teeth can only be fully examined under anaesthesia, and this is recommended if there is a strong suspicion of dental disease based on the symptoms described above.
It is important that your rabbit has a health check every 6-12 months, such as during their yearly vaccination appointment, as this allows your vet to keep a close record of their normal bodyweight, and get your rabbit used to having their teeth checked.
Diet is the most important factor for keeping your rabbit’s mouth healthy. Pet rabbits fed a natural diet have a much lower incidence of dental disease compared to those fed a commercial diet. Commercial diets also have higher levels of vitamins and minerals that can cause changes in the composition of the teeth and bones.[5]
The most important way to prevent the development of dental disease in rabbits is by feeding them a natural diet, which includes a mix of grasses and leafy greens, and can be supplemented with hay. This diet will stimulate a normal chewing pattern and, by encouraging longer chewing times, will result in a normal wearing down of the teeth. Although difficult, it is advisable to encourage rabbits accustomed to eating commercial (pelleted) diets to start eating a diet based on hay, grasses and leafy vegetables.
Allowing your rabbit to roam in the garden will help them have access to growing grass and other natural vegetation. It is still recommended that your rabbit's teeth are assessed by your veterinarian regularly (every six months), at the time of vaccination, or while visiting the vet for other reasons, so any changes noticed can be addressed in a timely manner before they become more chronic and difficult to manage.
Summary
Feeding an appropriate diet is essential to ensure your rabbit’s teeth wear properly and evenly. Lack of good quality roughage can lead to uneven wear, painful sores in the mouth and malocclusion of the teeth. A dental procedure can try to correct this, however, many rabbits will continue to have some dental problems even if their diet is improved.
Early detection of dental disease in rabbits is important. If a rabbit stops eating altogether, this can be extremely challenging to treat and even become life-threatening. Rabbit’s molars (cheek teeth) are impossible for you to see at home but will be examined during routine health checks. If you notice any problems with your rabbit that could be related to its teeth, it is essential to contact your practice and arrange a dental check as soon as possible.
