Dentition from Beginning to End, Including Disease Prevention and Treatment

Animals all share the same thing we humans do: dentition. Yet, across many animal species it is different; not only in the setup of their teeth but how to properly take care them. This paper will explain dentition from beginning to end including preventive and disease care. Also discussed will be dentistry instruments that are used to examine and treat dental problems in animals.

In equines, the deciduous teeth formula is 3/3, 0/0, 3/3, 0/0. Adult dental formula of an equine is 3/3, 0-1/0-1, 3-4/3-4, 3/3. The equine canine teeth, or tushes, erupt between four to five years of age and are short and can be sharp. They are located in the diastema, or gap, between the incisor teeth and cheek teeth on both the upper and lower parts of the mouth. Canine teeth are usually only found in male horses; but there sometimes can be canine teeth found on small mares.

The wolf teeth are small teeth and are found in front of the first upper cheek teeth. They erupt between six to eighteen months of age varying in size and position. Very rarely they are found in front of the first lower cheek teeth. Not all equine have wolf teeth and not all equine have fully erupted wolf teeth on each side.

Cheek teeth are the teeth that do all the grinding of the grass they eat. They help aide in digestion of the grass. Equine have a total of twelve premolar and twelve molar teeth that are divided equally on the left and right side into an upper and lower level of six. Premolar teeth have a deciduous precursor and are shed as a cap. In a healthy equine the cheek teeth arcades are composed in a tight unit. These teeth each act individually as a grinding tooth.

Dental disease can be prevalent in equines. It may cause pain or irritation where the horse may chew their food for a little while then drop it. Equines may only eat on one side of their mouth or pack food in their cheeks. If an equine is salivating more than usual they may be doing that to soften the food to make it easier to chew. An equine may also act out negatively when instructed to do something due to the pain. Long term problems include weight loss from not eating enough feed.

Besides feeding issues, mouth odor can be another indicator of oncoming dental disease. It can be a sign that there is food stuck in the diastema which leads to the disease. Food can become packed in that space and eventually start to decay. When the food decays it affects the gums, the tooth and surrounding bone causing infection. While some diastema will correct itself as the horse ages, in the cases where it does not, cleaning and packing of the gaps may be needed.

Pulpar disease in equines is often unnoticed. Equines do not have a nervous supply to the pulp so do not feel pain if the pulp is infected. The pulps are visible on the surface of their teeth. Simple exam can indicate if the pulp is infected. The tooth can cause jaw and facial swellings that can be painful or warm. This can lead to malodourous discharge. The upper and back teeth have roots into the sinuses. Swelling may go unnoticed and burst into the sinuses. That then will cause malodorous nasal discharge.

Dental caries in the equine is the destruction of dental tissue by bacteria in the mouth. Caries are found on the side of the teeth, (peripheral caries) or on the grinding surface of the upper cheek teeth, in an area known as the infundibulum. Peripheral caries usually do not cause problems. However, infundibular caries are more disposed to tooth fractures because they weaken the tooth.

Periodontal disease is one of the most painful diseases that can occur in an equine’s mouth. It causes premature tooth loss in adult horses. It can affect incisors, canine and cheek teeth. Equine teeth continually erupt over its life span. Tissues and surrounding teeth undergo normal changes as eruption happens. The periodontium contains the gingiva, alveolar bone, periodontal ligament and the cementum of the tooth. When there is normal mastication the mouth of the horse is self-cleaning. Feed and calcui do not accumulate on or around the teeth. This is part of the normal defenses such as salvia, white-blood cells, antibodies, and good bacteria.

In the field, veterinarians use specialized instruments to conduct an oral exam. Some are hand-held and some are powered. The stethoscope is used to check heart, lungs, and trachea before the examination. This is to ensure the airways and heart rate are normal before sedation. When the horse is sedated, do not make a lot of noise as it may startle them. A steel bucket with rubber on the bottom is used to prevent the instruments from making noise while being carried in the bucket. In a separate bucket with water, a little detergent and soap is added and used to rinse the horse’s mouth with a dose syringe. It is sprayed into the mouth to rinse it before the oral exam. A full mouth speculum is fitted to the horse right into the mouth. It enables the veterinarian to put a hand in the horse’s mouth. A head rest can also be used to support the horse’s head. For light sources a head lamp is worn to light up the mouth allowing the exam and teeth work to be conducted hands free. It is important to ensure that the horse does not eat for ninety minutes after any work is done. A horse muzzle can be put on the horse to prevent them from eating or drinking water.

There are multiple types of hand held instruments for the examination and work on equine teeth. Dental mirrors are used to visualize fractures and fragments of teeth that may be invisible without it. Dental picks come in assorted sizes to check the teeth to see if there are holes or grades in the teeth. Extractors are used to pull out baby or cheek teeth. Cheek retractors are used to remove the cheek from the teeth to work more freely. Surgical sets, which contain elevators, are designed for removal of wolf teeth.

Power tools can also be used to assist. Carbine burs help smooth out sharp points of the horse’s teeth. Hearing guards and masks are used to protect the veterinarian from dental dust. It is not good to inhale the dust in everyday. A tank with high pressure can be used to rinse the horse’s mouth after procedures are done.

In an equine hospital, similar instruments are used as in the field: a speculum for the mouth, and a dental mirror for observation. However, there are other tools that a hospital has at its disposal. One is the periodontal probes. As with human dentistry, the probes help to examine areas of the teeth that appear abnormal or where pockets may be forming from oral decay. Water picks aid in the cleaning of diastemas. This helps a more thorough exam be done on the mouth. Molar pullers are used to pull loose teeth that may be causing the equine pain. Digital radiography is used in aid of visualization of teeth. This helps the veterinarian to see if there are any root abscesses, look at the tooth structure and surrounding bone.

Dental procedures are performed to create a good environment for chewing, nutrition and to prevent any future problems. Floating is done to removal sharpness on the upper and outer cheek teeth. Equilibration is removal of overgrown areas of cheek teeth. This allows all teeth to touch when and how they are supposed to. That is what helps makes mastication more efficient. Another procedure helps correct malocclusions which occur between the cheek teeth and incisor teeth. Malocclusion causes poor grasping or chewing of food and loss of teeth if not corrected. It can even lead to behavior problems and disrupt performance.

Bit seats are a very important part of dental care in the performing equine. They help to round and to angle the upper and lower first cheek teeth to prevent the bit contact with cheek teeth. Bit seats help to give the rider better control by eliminating the distraction when bit contacts with teeth. It also helps the bit seats from riding down the tongue.

Canine tooth reduction is the process where the teeth are rasped and contoured. It helps to shorten them. While some equines benefit from them, some do not. Each dentist should evaluate their patient to see if it would be a benefit. Transverse ridges are surfaces on teeth that are too tall or have a sharp point at the top of the tooth. If not taken care of they interfere with chewing and back-to- jaw motion. Wolf teeth are small teeth are found in front of the first upper cheek teeth. These are not functional for grinding and are usually removed. This prevents pain in the horse when it is ridden.

Post dental care involves observation of the equine. How is the equine when it is chewing its food? Is it keeping the feed in the mouth or is it dropping some of it still? Does the equine need to be confined or have a muzzle put on its mouth for ninety minutes? This will prevent the horse from eating until it is awake enough from the sedation. Does the equine need antibiotics or pain medication? Some procedures may be clearing up an infection, some are painful. Scheduling dental exams with the veterinarian are important while remaining diligent in the equine’s dental needs throughout its lifetime.

A rodent’s dental formula is Incisors 1/1, Canine 0/0, Premolars 0/1, Molars 3/3. Their teeth are known as heterodont dentition. Instead of canine teeth they have a long diastema between incisors and cheek teeth. There are two types of teeth that the rodent has: aradicular hypsodont and, in some species, brachydont cheek teeth. Upper and lower incisor teeth come to a chisel-like point. Enamel is on the front and lateral sides of the teeth only while cementum and dentin are on the palatal/lingual surface.

This explains why the incisors are more chisel like - the cementum and dentin wear a lot faster than enamel. Enamel of the incisors in rodents takes on a yellow-orange color. Hypsodont cheek teeth are often angled rather than flat occlusal table. The highest point of the chisel tip maxillary cheek teeth is on the buccal side angling towards the soft tissue of the hard palate. The bevel of the mandibular cheek teeth goes in the opposite direction. The chisel point of the mandibular cheek teeth is on the lingual side. The tooth’s occlusal table angles towards the soft tissue of the cheek. These wear patterns are due to the maxillary cheek teeth being spread wider apart at the midline than the mandibular teeth. This is termed anisognathic, or unequal jaw relationship, meaning the upper dental arch is slightly wider than the lower. Periodontal ligament of permanent aradicular hypsodont teeth may differ from brachydont teeth. This is due to the presence of the periodontal ligament between its tooth and bone attachments. The plexus may allow continually growing teeth to move upward as they grow.

Some dental issues seen in rodents can be a result from insufficient gnawing; as their teeth continuously grow this can lead to overgrowth of incisors. Incisor injury can lead to malocclusion. Rodents are also prone to cavities and periodontal disease. This is caused by the same bacteria that cause cavities in humans. Rodents can get this bacterium from kissing their owners and sharing food. Poor nutrition can lead to dental and bone abnormalities. Other problems that can occur are decreased appetite and weight loss. Saliva will build up on the inside of the lip, under the chin and inside of the front legs. The rodent may show reluctance to eat anything hard or anything at all. Their breath will stink. Lumps can appear under the cheek or eye or even the lower jaw. Increased tears can occur in one or both of the eyes. Chewing movements can be seen in the rodent’s mouth when it is not eating. If incisors are present and uneven most likely the cheek teeth are abnormal also. This can also to lead to trouble closing the mouth. Slobbers is a common dental disease that rodents get. That is where drool is evident and a constant wet chin. Abscesses can develop in the rodent. An abscess is a thick pocket of pus that is surrounded by a capsule of thick tissue. Rodents have thick creamy pus that does not drain well. The abscess is their body’s way in fighting off infection. Since the thick tissue prevents antibiotics from getting to the infection, surgical intervention is usually needed. If the abscess becomes large it can affect the teeth and the surrounding bone.

Instruments and equipment in dental care for rodents are varied. Towels can be useful to help restrain them. A laryngoscope with a small pediatric blade is used for endotracheal intubation to maintain the airway and to administer anesthesia. Endotracheal tubes come in sizes 1.5, 2.0, 2.5, or 3.0 Cole. A wire stylet can be used to help place the tube more easily. Otoscopes with ear or nasal cones to help visualize the teeth and oral cavity of small animals. Intravenous catheters can be used as an endotracheal tube for smaller rodents if the stylet is removed. The catheters should be 12 to14 gauge. Umbilical tape is used to anchor the endotracheal tube snugly by tying it behind the rodents head. Cotton tipped applicators are used to clear out saliva and moisture and debris out of the rodent’s mouth. Explores and probes are used to examine the teeth their attachment structures. Hand pieces that are used in dental care for rodents are both high speed and low speed.

Tongue retractors are instruments with a flat blade that assist in moving the tongue away to view a certain area of interest. Mouth gags are used to keep the mouth open during the procedure. Most mouth gags are spring activated and can be adjusted to open wider with the turn of a screw device. Burs - such as diamond, carbide round, carbide tapered fissure, and white stone points - are used as a hard tissue device. Files/rasps are used to level abnormally occlusive teeth. Rasps cut on both the push and pull stroke and files only cut on the pull stroke. Molar or cheek teeth cutters may be modified hard tissue-nippers, pin and wire cutters pliers, or side cutting rogers. Elevators are used to work around the circumference of the tooth in the periodontal ligament and help in aiding the removal of the tooth. Blunted injection needles sized 18-25 can be used also for removal of teeth. Small animal extraction forceps are used to extract teeth that are loosened or diseased. With cheek teeth, a small 90-degree angled Halsted mosquito forceps with an angled root tip can be very useful for cheek teeth extractions.

Anesthesia is used to sedate the rodent and is available in two forms: injectable and inhalant. When injectable medications such as Ketamine and Acepromazine are used it usually entails a longer recovery time than inhalants. Inhalants such as Isoflurane and Sevoflurane are preferred for most anesthesia procedures. Anesthesia and oxygen may be delivered through the endotracheal tube.

After any dental procedure is done, continue at home dental care for the rodent. They should be given hard objects to gnaw on. Since their teeth continuously grow, the length will need to be monitored. The top incisors should be no more than 4mm long and the bottom incisors should be no longer than 7mm long. Most rodents will need to have them filed down every so often if gnawing isn’t helping. Cheek teeth also need to be checked because they can overgrow also. This is mainly to make sure the top and bottom teeth align so they can grind against each other.

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