This article is from the WSSF 2006 AFRMA Rat & Mouse Tales news-magazine.

By Cathleen Schneider-Russell

A Rat Skull. Drawing by Sheryl Leisure.

A Mouse Skull. Drawing by Sheryl Leisure.

This is from a lecture I had attended in 2004 called “Common Dental Problems In Rabbits, Guinea Pigs, Chinchillas, and Rodents: Treatment & Prevention.” Dr. Sari Kanfer was the speaker. She is with the Animal Medical Group, Small Animal & Exotics Medicine, Surgery and Dentistry, 1401 N. Sepulveda Blvd., Manhattan Beach, CA 90266, Tel: 310.546.5731, e-mail: amgpetdental@aol.com. She consults with Dr. David Crossly in England. He is a dental specialist that created specialized instruments/studies/treatments/etc., for these animals. Here is the Rat/Mouse information.

Terms:

Cheek teeth: premolar and molars in rabbits, guinea pigs and chinchillas

Root: the part of the tooth residing in the bone

Crown: the part of the tooth exposed in the mouth

Occlusion: how teeth meet

Malocclusion: abnormal occlusion

Occlusive angle: the angle at which the teeth meet when viewed from the front

Dental Arcade: row of cheek teeth on one side, upper or lower

Rats, Mice & Hamsters:

• Skulls are similar to chinchillas, but with less cheek teeth (3)
• Incisors grow continuously, cheek teeth stop growing (like human molars)
• At rest, cheek teeth are touching and incisors are parted
• Chewing motion is forward-back
• Occlusive edges are flat, and therefore can slide back and forth
• Pigmented enamel on front of the incisors (iron) (note: yellow=normal) = good health
• Occlusive angle of arcades is straight

For exam use regular otoscope with special fitted speculum

Rats, Mice, Hamsters:
These rodents have evolved to be omnivores. Like humans, they eat vegetation, grains, and meat, and some species of rodents eat insects as well. With less vegetation in their diet, there is less wear on the cheek teeth, thus no need for continuously growing cheek teeth. They do however have continuously growing incisors for all the gnawing and tunnel building they need to do.

• Insufficient gnawing can lead to overgrown incisors
• Incisor injury can lead to malocclusion
• Rodents can get cavities and periodontal disease. This is caused by the same bacteria that causes cavities in humans—rodents get this bacteria from kissing their owners and sharing food.
• Hamsters have large cheek pouches—injuries from sharp edges on foods can cause abscesses
• Poor nutrition during development can lead to dental and bone abnormalities.

Two words: PROPER DIET! Gnawing material and a balanced varied diet for rats, mice, and hamsters.

A good oral exam by your exotics vet is extremely important to try to identify problems in the earlier stages. Looking into the mouth with an otoscope while awake, we can only see a few of the cheek teeth. With rabbits, we can get a general idea if there is a problem, but with the smaller mouths of guinea pigs and the other rodents, it is very difficult to do a good oral exam awake. Ideally, a short episode of anesthesia with a thorough oral exam and skull x-rays is indicated frequently, perhaps even annually. Early treatment of dental problems will decrease severity of disease and limit pain and suffering.

Once dental problems are present, signs include:

• Decreased appetite, weight loss
• Saliva or food buildup under chin, near lips, on the inside of the front legs
• Reluctance to eat hard food, or any change in appetite
• Stinky breath
• Lump on the outer cheek, under the eye
• Lump under lower jaws (lumps start small, but can get very large)
• Discharge from cheek or chin/lower jaw area
• Incisors that are uneven (gently lift upper lips to check incisors). If uneven incisors are present, there is a very good chance that the cheek teeth are abnormal as well.
• Increased tears in one or both eyes
• Chewing movements when pet is not eating
• Drinking more

Most commonly, you will not see any signs until subtle problems have been present for a long time.

Grass hay and vegetables are too soft and not as coarse as weeds and wild grasses, this is why I encourage owners to feed their rabbits and rodents branches and leaves from safe trees¹, as well as unfertilized and untreated weeds from your yard.

• Maloccluded incisors can be trimmed with a dental drill. Cutting incisors with nail trimmers or bone cutters is not the best method, though is commonly done. It can cause splitting of the tooth longitudinally, resulting in infection of the root. It also causes trauma to the tooth as well as pain from the concussive forces.
• Abscess treatment depends on the location and severity. An abscess is a pocket of pus surrounded by a capsule of thick tissue. This is the body’s attempt to wall off infection. Rabbits, guinea pigs, chinchillas, and rodents have thick creamy pus that does not drain well, so just lancing an abscess is not enough. The abscess capsule prevents antibiotics from getting to the infection, therefore surgical removal of the abscess is usually necessary. Smaller soft tissue cheek abscesses are the easiest to treat, and we can often get full resolution of the abscess. If the abscess is large or involves a bone infection or infection around the teeth, then more invasive surgery is needed, and there is less chance of complete resolution. These cases call for the veterinarian to remove as much abnormal and infected tissue as possible and then place antibiotic-impregnated bone cement beads in the area. This allows for high concentrations of antibiotics at the site of infection, plus it will last 2–6 months or more. All that is needed for an abscess to recur is a few abnormal cells or compromised tooth root health; therefore, full resolution is difficult.
• You want to make sure that an experienced exotic vet is treating any of these problems. And remember, these are lifelong problems that need timely vet exams and many times requires regular anesthesia and dental care.
• Tear duct obstruction may possibly be a dental or eye problem.
• Traumatic injury to teeth can lead to long term problems or if your pet is lucky and your vet keeps the mouth balanced until the teeth grow back, many times these pets can return to normal.
• Cavities and periodontal disease in rodents: the recommendation is to avoid spreading your bacteria to your pet, but if you do, brush their teeth. (Note: use baking soda with water or flavored mouth wash on a q-tip)
• Malnutrition and congenital diseases: chronic management to keep pet comfortable. Often involves long term pain meds and antibiotics.

Dental health is extremely important to your pet’s happiness and well-being. Rabbits, guinea pigs, chinchillas, rats, mice, and hamsters have different dietary needs and different dental physiology than dogs, cats, and people. It is very important to understand that these differences exist, and it is important to have your pet regularly examined by a veterinarian that understands dental care in these species.

1: Safe trees: elm, ash, maple, birch, apple, orange, pear, peach. Avoid cedar, plum, redwood, cherry, and oleander.

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