When Teeth Turn to Tusks
It’s a good thing people with crooked teeth aren’t disposed of, or many of us would have been “culled” as children. Our bunnies don’t wear braces, but we will explore some dental options in this two-part article. In addition, a guide to preventive oral health care is also discussed.
In Part 1, Dr. Susan Brown, of the Midwest Bird & Exotic Animal Hospital in Chicago, gives us some very good reasons for one of these options–surgery. Extraction is something I would not have considered for any of my rabbits, but after talking to Dr. Brown, I learned that this is the best solution for some rabbits with malocclusion. Dr. Brown does not perform the surgery for owner convenience or for behavior problems, such as furniture chewing, but rather for the best interest of the animal and when the chances of better health are greatly improved.
Part 2 discusses procedures used when surgery is not a viable option, such as for very old, disabled or severely compromised animals.
Rabbits are quite prone to disease of the teeth. There are a number of causes of dental disease, and I would like to discuss a surgical treatment for disease of the incisors.
Rabbits have six incisors, or front teeth, four on the top and two on the bottom. The second set of upper incisors, called peg teeth, are hidden right behind the set that you can see easily when you look in the mouth. These teeth are used primarily for grabbing food and cutting it. (They are also very good for nipping through extension and phone cords!)
The rest of the rabbit’s teeth are located in the back on either side of the mouth. These molars are used for grinding the food. All of the teeth grow continuously throughout the rabbit’s life, and are kept worn down by the action of chewing and grinding of tooth against tooth. Rabbits do not require sticks or other items to chew in order to keep the teeth at the proper length, because the teeth take care of themselves by grinding against each other whenever the rabbit is eating. You also may hear your pet “grind” her teeth during resting, or at other times when she is relaxed and content.
CAUSES OF MALOCCLUSION
When the teeth get out of alignment, then we see them become overgrown. There are three causes for malocclusion of the teeth:
- Congenital–the rabbit was born that way. This is common in the “short faced” breeds such as dwarfs and lop.
- Trauma–when the rabbit has an injury to the face leading to disruption of normal growth of the tooth roots.
- Infection–bacterial infection of the tooth roots can lead to changes in the direction of the tooth growth.
All of these problems can occur in any of the teeth, but I will discuss treatment only of the incisors in this article. Whenever one sees a malocclusion of the incisors, always check the molars, because overgrown molars can be either the cause or the result of the incisor problem. If only the incisors are treated and the molars are neglected, then treatment will fail. Overgrown molars and sharp spurs on molars are a common cause for rabbits to stop eating and still be active and alert. (All non-eating rabbits are not hairball candidates). It is quite simple to view the molars with a human nasal speculum or a canine vaginal speculum.
Once the incisors are maloccluded, they are of no benefit to the bunny, and in fact can be uncomfortable. The rabbit learns to use his very mobile lips to pick up the food and get it into his mouth. One treatment for incisor overgrowth is to continually clip them. Many people use dog nail trimmers, which is a risky thing to do, because it is quite easy to fracture a tooth and break it off at the root. This is not only painful, but it can introduce infection into the root. If trimming is the treatment selected, then we recommend using a Dremel tool with a sanding disk or dental burr to cut teeth.
After years of trimming bunny teeth, and teaching owners to do it, I felt that there must be a better way. Many owners tire of the process, which sometimes must be done every four to eight weeks, and either let the teeth grow dangerously long or even have their bunnies destroyed. I also observed many bunnies getting more nervous and harder to handle each time the procedure had to be done. I had heard that some veterinarians had pulled the incisors with great success.
My first incisor-removal surgery was on a 5-year old dwarf who had had malocclusion since he was a youngster, and had to be force-fed frequently. He was never up to normal body weight and generally in poor condition. The owner wanted to try this procedure, because the alternative was death.
I used Ketamine and valium for anesthesia and successfully removed all the teeth, which turned out to be easier than I had thought. We put him on antibiotics for about ten days as the holes healed over (no sutures needed). He was eating on his own at the end of the week and went on to put on more weight then he ever had before. He appeared more playful and mentally alert than before.
Since my first case, we have gone on to perform this procedure on over 25 rabbits. We have not yet seen a rabbit who did worse after the procedure. They learn to eat all their foods, including hay, within one or two weeks post surgery. Let me briefly go through what would be expected after such a procedure.
AFTER THE OPERATION
The day of the surgery the rabbit is usually quiet and may not eat anything. However, we have had some individuals who went home and ate five hours post-surgically. The following morning they usually start drinking water and picking at their pellets (pellets are extremely easy for them to to pick up with their lips). We recommend tearing up their greens into two-inch sections to make them easier to pick up. Don’t make the pieces too small as it can be quite difficult for them to grab with their lips. Initially, we also recommend breaking up the hay into three- or four- inch sections until they “get the hang of it.” Try to avoid force feedings for at least 48 hours, if the animal was initially in good condition. This can be uncomfortable and can prolong the time before the bunny eats on her own.
By two to three days post surgery, most rabbits are eating 75 to 100% of their presurgery amounts of food. There are occasionally rabbits who will change change dramatically in their eating habits after surgery, such as not eating certain foods or losing interest in hay, but 90% of our patients go back to the presurgery diet.
We recommend using antibiotics post surgically for at least 10 days. At that time the bunny should be rechecked at the veterinary clinic to make sure healing is normal and that no discharges are present. If an infection is suspected as the initial cause of the malocclusion, X-rays should be taken to evaluate all the teeth prior to surgery, and cultures may need to be taken. Antibiotic therapy in these cases may need to be used for a much longer period of time.
In cases of congenital malocclusion, the earlier the surgery is done, the easier it is on the surgeon and the patient. Any veterinarian needing information on this procedure may contact our office (312/344-8166).
In conclusion, we feel that this is a valuable surgical procedure to alleviate the problem of overgrown incisors in rabbits. It has proved to be both humane and beneficial to the patient. I hope its use prevents the destruction of many rabbits.
In the last issue, we printed an article by Susan Brown, D.V.M., about the causes of malocclusion and dental disease in rabbits and, in particular, Dr. Brown’s experience in extracting incisors. In this ssue we present additional information about rabbit teeth, alternative methods of dealing with malocclusion of incisors, and one bunny’s experiences with personalized dental care.
When Buster came to us in 1987, after her elderly owner died, she was in good health, self-confident and weighed about 9 pounds. But her bottom teeth extended like two tusks from her lower jaw up past her nose. Even worse, the upper incisors were curling back into her mouth.
I had heard of malocclusion but never seen it. Fortunately, Buster’s molars are fine and she can easily eat pellets and greens. Larger food (carrots, apples, etc.) must be cut into very small pieces. After a few attempts at trimming the teeth on our own, we found an experienced veterinarian, Jill Chase, who now does this every month or so (shehas also taught us how to do it if needed). For three years we settled into a routine of food chopping and tooth trimming.
Then last year near-disaster struck. Buster stopped eating and, in fact, was unable to eat. Dr. Chase immediately discovered a severe gum infection, probably from feces that had been trapped between her abnormal teeth. Buster was in too much pain to eat. She had gone without food for a dangerously long time because rabbits who don’t eat for just 24 hours can be in serious trouble. X-rays showed that her intestinal tract was already filled with gas. It was important to get food into her as soon as possible.
The gum infection could be treated easily with antibiotics and frequent teeth cleaning with a diluted antiseptic. But after two days in the hospital she still couldn’t eat and had lost two pounds. Dr. Chase said Buster would be better off at home–near my food processor. And that’s when the real trauma began.
We food-processed her regular pellets (soaked in water until soft) with a lot of water (I later found a hand-held blender works better as smaller amounts can be made). By placing a feeding syringe between Buster’s lips on the side of her mouth and pushing the plunger slowly (so that food would not be inhaled), Buster could, theoretically, slurp as much food as she wanted.
At first Buster hated the whole business and it was a huge struggle, especially since we were urged to get as much food into her as she would normally eat. That’s a lot: dry pellets expand roughly three times their normal size when soaked. I added cooked oatmeal and gradually learned that the consistency was very important: the right balance of water and oatmeal made the food creamy and palatable; too little of either and she spit it out. Fruit like papaya, banana or apple improved the flavor. After a few days Buster was greedily slurping down about 180 ccs a day. I was feeding her every two to three hours to avoid bloating.
After two weeks, Buster thrilled us by eating again, though she stuck to mashed pellets and finely-grated carrot for a few more days. Since then, we’ve cleaned Buster’s teeth regularly and avoided further gum problems.
Last fall a new episode started the whole process again. Buster jumped down unexpectedly to a brick floor and landed hard. I noticed a cut lip and chipped tooth but no other damage. Her teeth and gums seemed healthy, but from then on she wouldn’t eat and this time seemed to be in a different kind of discomfort. We were doing the best we could, but Buster was really upset and angry during every feeding. Then one night she was very hungry and tried to eat a piece of grape–and choked. A night on oxygen pulled her through. More intense examination revealed a suspected broken lower jaw.
This time the feedings lasted six weeks, until the jaw healed. We had to work very slowly, being careful not to jostle her jaw. Although in the past I could feed her alone by wedging her between my legs and leaning over her from behind, this time my husband’s assistance was required to ensure no further trauma to the jaw.
After three weeks Buster began eating mush on her own, supplemented by syringe feedings. Six weeks after the injury, Buster ate her first bowl of dry food and has been making up for lost time ever since. After dropping to less than six pounds, she now weighs nearly ten pounds.
Buster obviously understood her own needs. During this ordeal, she demanded–and received–much extra nuzzling and hugging. During recovery she spent hours every day chewing on a small branch from our lemon tree, moving the branch from one side of her mouth to the other (which kept her molars in good shape). As soon as she could eat dry food on her own, she never touched the branch again.
We never considered extracting Buster’s teeth because of her uncertain age (she’s at least six), one major surgery to remove mammary tumors already under her belt, and–more importantly–she does fine as she is. Despite the occasional extra work for us, there are advantages. Feisty and uncooperative when she first came to us, she is now affectionate, trusting and easy to handle. And she can’t chew on harmful or expensive things around the house.
Buster’s Favorite Puree
2-3 TB softened pellets
1 TB cooked rolled oats
1-2 TB fresh papaya, banana,
apple or finely grated carrot
Put everything in a small food processor and puree. Add plenty of water until very smooth. Store in the refrigerator but set out at room temperature for about 15 minutes before feeding. More water may be needed after refrigeration. Make a fresh batch at least once every 24 hours. Have plenty of towels and wash cloths available for clean up until bunny and feeder get used to the experience.
Rabbit teeth are open-rooted, which means they grow continuously, like fingernails. Althought rabbits have a total of 28 teeth, only four–the two upper and two lower incisors–are visible during routine examination.
Normally, the teeth are straight and meet in perfect alignment. The molars are kept short through natural grinding action during eating. Incisors are kept short and sharp by chewing on pieces of wood and other objects. If the rabbit doesn’t keep her teeth in good condition, she may not be able to eat.
Rabbits use their incisors in many ways: to grab or bite off pieces of food, show affection, groom and defend themselves. Anyone who has been bitten by a rabbit or tried to release a towel from its grip will be impressed by the strength of the small jaws and teeth.
When a rabbit has malocclusion, the teeth do not align properly. As described in the last Journal, malocclusion can be caused by congenital conditions, trauma or infection. In some cases, such as Buster’s, the teeth are also crooked, turning outward or inward. This can increase the chance of infection if food, fur or other material gets trapped between the teeth and close to the gums.
Malocclusion can be treated by regular trimming of the incisors. In the last article, surgical extraction of crooked incisors was presented as an option for treatment. I have found that this is rarely necessary. Regular trimming of the incisors is a safe, non-traumatic, practical and inexpensive method of correcting the over-growth of the incisors. It takes only minutes to perform. It is best to have a veterinary professional who is experienced with rabbits do the trimming or teach you how to do it to avoid chipping or splitting the teeth.
Problems with molars occur less often, but they, too, can be maloccluded. Since molars are very hard to see, it’s a good idea to check them if a rabbit is coincidentally sedated for any other purpose. Another molar risk is retrobulbar abscess, caused by food being trapped behind a molar.
Rabbits with a history of dental problems should be watched closely. Signs of infection in the mouth may include loss of appetite and listlessness or sluggish activity levels. A rabbit who is unable to eat might attempt to chew food and then spit it out, or he may beg for food. It is important to remember that rabbits cannot go for long periods without food. The motility of the intestinal tract can be impaired and ultimately the rabbit may die. If the rabbit cannot eat on her own, your veterinarian can advise you on what to do. Some rabbits, like Buster, will let you know there’s a problem because they will stick more closely near their human companions when in trouble.
Infections of the mouth are treated with antibiotics, and the area must be kept clean. Healthy gums are light pink; diseased gums will be bright red, grey or even white. All infections should be brought to the attention of your veterinarian so that proper treatment can be initiated. If a broken jaw or other skeletal problem is suspected, the rabbit should be x-rayed. As seen in Buster’s case, rabbits will recover from such fractures at about the same speed as humans. It is very rewarding to perform such a simple procedure as trimming a rabbit’s incisors to correct what could be a life-threatening problem. I have found that rabbits who require frequent handling for dental care tend to become more accustomed to being handled. This proves advantageous for everyone concerned as all other care required throughout the rabbit’s life may be tolerated more easily.
by Diana Petty
House Rabbit Journal Volume II No. 5