Dental disease

A guide to dental disease in rabbits

 

What is dental disease?

Our responsibilities

Treatment

 

What is dental disease?

Rabbits’ teeth

 

Rosie often slept displaying her incisors!

Rabbits have 28 teeth:

·      6 incisors:

o   4 upper incisors (2 smaller upper incisors (peg teeth) sit directly behind 2 larger upper incisors).

o   2 lower incisors.

When the rabbit’s mouth closes, the lower incisors’ tips rest between the larger upper incisors and peg teeth, and they rub against each other as the rabbit uses them to bite, which keeps them sharp and worn down correctly.

·      22 premolars and molars (or cheek teeth):

o   6 upper cheek teeth each side.

o   5 lower cheek teeth each side.

The cheek teeth are all identical (no difference between premolars and molars). The upper molars slightly overlap the lower molars (the lower jawline is slightly narrower than the top), and rabbits have a chewing motion that is both side-to-side and backwards-forwards, which helps to keep these teeth worn down evenly.

Diagram to show positioning of a rabbit’s teeth.

There is a space between the incisors and premolars called the diastema (a gap which is very useful if a rabbit’s mouth is tightly shut when you’re trying to administer medicines or food via a syringe!).

Rabbits’ teeth are elodont – they grow continuously, and they are open-rooted. Their incisors grow a couple of millimetres per week. This isn’t a problem for wild rabbits, as they have a diet consisting of mostly grass or hay, so the teeth are ground down.

Dental problems affecting domestic rabbits

Dental problems are widespread in pet rabbits. They can be affected by numerous issues, but the most common problems are:

·      Elongation – the rabbits’ teeth or tooth roots growing too long.

·      Malocclusion – the teeth not aligning when the rabbit bites, so that they don’t wear down evenly, and sharp spurs form on the edges.

Dental disease can cause any of the following symptoms:

·      Cuts on tongue, cheeks, and gums from sharp spurs formed on teeth (this can make it painful for a rabbit to eat).

·      Abscesses (painful swellings around the overgrown teeth or below elongated roots on the lower jaw).

·      Overgrown front incisors can grow at an angle out of the rabbit’s mouth, or curl back and cut into the gums.

·      Eye problems (roots of overgrown upper teeth can squash the tear duct, especially in flatter-faced breeds where the teeth are more directly beneath the eye socket. There may be discharge from the rabbit’s eye, and it can cause eye infections. It can also cause abscesses to form behind the eye).

Our responsibilities

The best way to protect rabbits from dental disease is to reduce the risk of their teeth becoming overgrown, and take measures to keep their jawbones healthy.

Dental problems can be caused by several factors:

·      Congenital problems – Some rabbits are more prone to dental disease, especially lop eared and dwarf rabbits. Those with a shortened face/smaller skull (eg. Netherland dwarf rabbits) often have overcrowded teeth, resulting in malocclusion. These rabbits may require dental treatment throughout their lives.

·      Poor diet – Dental problems are frequently linked to an improper diet. Our domestic rabbits’ wild ancestors have a low energy, high fibre diet. Just like their ancestors, our rabbits’ digestive systems require large amounts of digestible and undigestible fibre (hay or grass) and so do their teeth:

o   Chewing of grass or hay requires rabbits to grind their jaw in a special circular movement that wears down their teeth (this movement isn’t required when they eat pellets or greens).

o   Grass and hay contain long fibres and abrasive silicates which wear the teeth down perfectly.

o   Exercise of the jawbone through chewing fibrous hay/grass even helps to ensure a good bone density, helping to prevent tooth roots growing too far into the jaw.

Wild rabbits have evolved to maximise the energy from this low nutrient diet, and will naturally select the higher energy vegetation first. Our pet rabbits do the same, selecting higher energy foods first, so they will choose commercial foods and treats over hay or grass. If we provide too many carbohydrates (pellets/muesli-type food), their natural tendency to eat selectively means they fill up on the commercial food and don’t eat enough hay/grass. With insufficient fibre to wear them down, their teeth grow too long and start causing problems. They also risk becoming overweight from selective feeding, and may experience an imbalance in their digestive system from not eating enough hay.

·      Inadequate exposure to sunlight – without adequate sunlight, rabbits can suffer from poor bone density (due to Vitamin D3 deficiency). Elongated tooth roots are more likely in soft jaw bones.

·      Trauma or injury – teeth may become damaged or maloccluded due to an accident, or jaw may be fractured.  

Addressing these problems is vital to reduce the risk of a rabbit developing dental disease.

Here are some examples, for each of the Five Welfare Needs, to show how providing for rabbits’ welfare can reduce the risk of dental disease:

·      Suitable environment:

o   Constant access to good quality fresh hay or grass.

o   If possible, exposure to direct, unfiltered sunlight to avoid vitamin D3 deficiency.

·      Suitable diet:

o   Ensure that rabbits’ diet consists of at least 85% fresh hay or grass – encourage them to eat hay or grass by adding forage and decreasing the amount of pellets, treats, and greens fed.

o   Feel a minimal amount of pelleted food (excessive carbohydrates and too much dry food can also increase the risk of gut stasis).

o   Feed any pellets and greens later in the day, so rabbits fill up on hay when they’re most hungry in the early morning, rather than selecting the higher energy food.

o   Avoid muesli-type mixes – these have been shown to cause dental disease.

·      Enabling rabbits to exhibit normal behaviour patterns behaviours:

o   Scatter-feeding/hiding food helps to encourage activity by foraging, so that rabbits don’t fill up straight away on high energy foods and neglect eating hay/grass.

o   Provide a variety of items to chew – branches of rabbit-safe trees (eg. apple, willow, and hazel) and wooden chew toys, to help to keep teeth in trim.

·      Providing at least one rabbit companion:

o   Bonded rabbits will help each other groom, which is especially beneficial if one suffers from dental disease and has trouble keeping clean.

o   A rabbit reluctant to eat hay can be encouraged to do so when seeing a companion enjoying hay.

o   When adopting a new companion for a rabbit, don’t buy rabbits prone to dental disease (those with shortened faces or lop-eared rabbits) from breeders or pet retailers. If people continue to buy these ‘cute’ breeds, breeders will continue to supply them, and the market (and, therefore, the rescue centres) will continue to be inundated with rabbits prone to lifelong dental disease).

·      Suitable health care:

o   Make sure any dental problems are treated or managed, so that rabbits can eat hay or grass.

o   Make sure rabbits have regular vet checks, to spot any dental issues which may cause them to stop eating hay or to become inactive.

Check rabbits regularly

Unfortunately, even if we provide a good diet, there is still a risk of dental disease, especially in certain breeds.

The following can all be signs of dental problems:

·      Reduced or complete loss of appetite (from pain or difficulty eating).

·      Reduced number/size of droppings (because of reduced appetite, and insufficient fibre intake).

·      Weight loss (because of reduced appetite).

·      Leaving partly chewed food.

·      Drooling (wetness around chin and neck, and front paws from cleaning, due to inability to close mouth, or from excess salivation caused by pain).

·      Discharge from eyes or nose (caused by elongated tooth roots blocking the tear ducts or irritating the sinuses).

·      Lumps on or beneath jaw (from abscesses forming around the teeth or below elongated roots on the lower jaw).

·      Gut stasis (if eating is painful and a rabbit loses appetite, the gut will slow down).

·      Messy bottom (due to difficulty eating caecotrophs or cleaning rear end – this increases risk of fly strike).

·      Ear infections.

·      Respiratory infections.

·      Loud grinding of teeth (indicates pain).

·      Other signs of pain (see our list of daily health observations).

If you notice any signs which could indicate a dental problem, consult a vet. 

Radiography is essential for suspected dental disease –
here’s a lateral view of Dijon’s teeth.

Treatment

Veterinary treatment includes:

·      Diagnosing the problem – physical examination; x-rays may be required to check back teeth and jawbones.

·      Pain relief.

·      Nutrition and hydration.

·      Trimming of teeth.

·      Teeth extraction under anaesthesia.

·      Surgery and antibiotics for abscesses.

·      Treat any signs of gut stasis.

·      Guidance on diet.

·      Encourage rabbit to eat hay.

Sadly, many rabbits with dental problems will require veterinary treatment throughout their lives.

Remember: Feeding mostly hay or grass
is the best way to reduce the risk of dental disease!