Teeth and Gums Basics in Dogs
With rare exceptions, puppies are born without teeth. The first teeth to erupt are the incisors, at 2 to 3 weeks of age. Next are the canines and premolars. The last premolar erupts at about 8 to 12 weeks of age. As a rule, the teeth of larger breeds erupt sooner than those of smaller breeds.
The average puppy has 28 deciduous (temporary or baby) teeth. These are the incisors, canines, and premolars. Puppies don't have molars.
The deciduous teeth remain for only three to seven months. Beginning at about 3 months of age, the baby incisors are shed and replaced by adult incisors. By 5 months, a puppy should have all her adult incisors. The adult canines, premolars, and molars come in between 4 and 7 months of age. Thus, by 7 to 8 months of age, a puppy should have all her adult teeth. Knowing this teething sequence can give you an approximate idea of the age of a puppy.
The average adult dog has 42 teeth: 22 in the mandible or lower jaw, and 20 in the maxilla or upper jaw. In each jaw there are 6 incisors, 2 canines, and 8 premolars. There are 6 molars in the lower jaw and 4 in the upper jaw.
In adult dogs, approximate age can be determined by checking the wear on the incisors. This method is relatively reliable up to about 6 years of age, but individual variations do occur. Beyond 7 years, using the teeth to determine age is unreliable.
Retained Baby Teeth
Normally, the roots of the baby teeth are reabsorbed as the adult teeth take their place. When this fails to happen, you will see what appears to be a double set of teeth. Toy breeds, in particular, tend to retain baby teeth as their adult teeth erupt. The adult teeth are then pushed out of line, producing a malocclusion or bad bite.
Treatment: Puppies 3 to 4 months of age should be checked from time to time to see that their adult teeth are coming in normally. Whenever baby teeth interfere with adult teeth, the baby teeth should be pulled. If this is done by 4 to 5 months of age, the bite should correct spontaneously.
Cavities are not common in dogs. When present, they usually form at the gum line and are related to periodontal disease. They can also occur on the crown of a molar. They appear as a black spot on the tooth. Cavities are painful and eventually lead to root abscesses.
Treatment:The quickest and easiest way to treat a cavity is to extract the tooth. The cavity can be filled and the tooth saved, but most veterinarians do not have the supplies and the equipment to fill cavities and will refer the dog to a veterinarian who specializes in dentistry.
Root canal therapy is also being done for dogs who have deep cavities that expose the tooth pulp. Root canals are fairly common today and can be especially useful for dogs with fractured canine teeth.
Root abscesses can affect any of the teeth, but the ones most commonly involved are the canines and the upper fourth premolars. Tooth abscesses are extremely painful and are accompanied by fever, reluctance to eat, and depression. You may see pus oozing around the tooth. X-rays confirm the diagnosis and show whether bone is involved.
An abscessed upper fourth premolar causes a characteristic swelling of the face below the eye. Eventually the abscess breaks through the skin and drains pus over the side of the face. A diseased tooth may break through the skin of the lower jaw and produce a similar condition.
Treatment: The abscessed tooth is extracted under anesthesia and the tooth cavity is cleaned and drained. In some cases the tooth can be saved by doing a root canal or endodontic procedure. Antibiotics are used to treat infection. Aftercare at home involves the use of chlorhexidine mouthwashes.
Broken teeth are common. They are caused by chewing on hard objects, such as stones and hard bones, by catching the teeth on the wire of kennels and cages, or by trauma.
Treatment: If the fracture involves only the enamel, the tooth is not painful and no treatment is necessary. However, a break in the crown that extends into the dental pulp can be extremely painful, and the dog may become depressed and refuse to eat. Restorative dentistry or extraction of the tooth will be necessary to prevent an abscessed root. Along with a root canal, a crown may be made to replace the damaged tooth. These can be made of metal or a new ceramic. This is most commonly done for working dogs such as police dogs. Dogs may not compete in conformation competition with a crowned tooth.
This article is excerpted from “Dog Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.
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