Unlike human and dogs, the teeth of rabbits and rodents grow continuously all their lives. In the wild, rabbits feed on rough grasses and weeds so their teeth are continuously being kept well worn down by this abrasive diet.
How many teeth do rabbits have?
We've all seen Bugs Bunny so everyone knows that rabbits have front teeth called incisors. What most people don't realise is that they in fact have 6 incisor teeth and 22 back molar teeth. The teeth grow about 2mm a week and there is a division of labour. The incisor teeth are sharp and chisel-like for slicing the food and grooming the coat while the cheek teeth are wide and flat with hard enamel for grinding down the food.
A rabbit with healthy teeth will eat a variety of foods and have no problems chewing large quantities of hay. The coat will be healthy and shiny and the rear area should be spotless with no faecal soiling visible. The incisor teeth will be short, of equal length and have a sharp chisel appearance. Looking into the back of a mouth with a veterinary instrument called a speculum the molar teeth will appear straight and regular.
What causes dental disease in rabbits?
Some dwarf and lop eared breeds have a congenital defect where the lower jaw is abnormally long compared to the nose. This means the top and bottom incisor teeth never actually appose and as they don't get worn down they overgrow. The lower incisors tend to grow out straight while the upper incisors begin to spiral ( like a walrus) digging painfully into the gums. Incisor overgrowth can start from as early as 8-10 weeks but often may go unnoticed until 9-12 months.
These overlong teeth can temporarily be trimmed with a special dental drill but if the problem keeps on recurring it is best to have these teeth extracted. Extraction in usually successful as rabbits only use these teeth to slice their food so can still eat well after surgery provided vegetables are sliced.
In some dwarf breeds the nose is shorter than the lower jaw so the incisor teeth overgrow.
Acquired Dental Disease
The most common cause of dental disease in rabbit is due to feeding your pet rabbit the wrong diet. Many owners make the mistake of feeding muesli type mix (instead of fibrous pellets) or not enough hay or grass. In the wild rabbit's chew on rough fibrous long stem grasses and weeds. To chew this abrasive diet their jaws appose one side at a time and rotate laterally at a rate of 120 times a minute. When a rabbit is fed a low hay or muesli type diet this normal chewing mechanism breaks down. The teeth don't wear down, the crowns get longer and longer eventually curving and digging painfully into the gums. The other problem is that rabbits graze by browsing ie selecting the finest shoots. If they are fed muesli type mixes, they will selectively eat the maize and dried peas leaving behind the pellets that contain the fibre and calcium needed for healthy dentition.
When the back or molar teeth get too long the problem becomes serious. The upper teeth get so long they tip sideways into the gums of the cheeks causing painful ulcers. The bottom teeth get even worse as they tip sideways creating a sharp spur which lacerates the tongue.
These rabbits are often in excruciating pain especially when spurs lacerate the tongue causing the graphically termed 'lingual kebab'. They stop eating, hide away and suffer rapid weight loss. Often, they drool and hunch up miserably due to the pain. As they can't eat they stop passing motions and get a secondary gut stasis.
These rabbits need to get to an experienced rabbit vet fast before they suffer and go downhill and die. These rabbits need to be hospitalised for assisted feeding, fluids to rehydrate them and pain relief. Once stable they will need dental surgery under anaesthetic to remove any painful spurs and burring down all elongated crowns to gingival level.