The mouth, or oral cavity, is a very important part of the digestive system in dogs. This is where digestion begins. As a dog chews, food is broken up into smaller particles for better digestion by enzymes in the stomach and small intestines. Teeth, therefore, play a very important role in digestion. The tongue and front teeth help a dog pick up pieces of food and teeth in the back of the mouth grind food into smaller particles.

In total, a dog has 42 teeth. They are comprised of the incisors and canines which are located in the front, and the premolars and molars which are located in the back. Each of these teeth have a part that is visible above the gum line called the crown as well as a part below the gum line called the root. Enamel covers the crown which is the hardest substance in the body. The dentin is below the enamel as well as the pulp which makes up most of the tooth's blood vessels and nerves.

The root of a dogs tooth sits in the jaw bone. Some teeth have only one root and some teeth have more than one root. The tissue that surrounds a tooth at the gum line is called the gingiva. The gingiva in a normal dog is attached tightly to the jawbone underneath.

Plaque, Tartar and Gingivitis

When a dog eats, food, saliva and bacteria will stick to its teeth. This is normal. This combination of food, saliva and bacteria is called plaque. Plaque is easily removed from teeth by brushing. If the plaque is not removed, it accumulates and causes irritation of the gums. The bacteria in plaque produce toxins which make the irritation worse. This inflammation causes breakdown in the gum and tissue surrounding the teeth. Inflammation of the gum around the teeth is called gingivitis.

Tartar occurs when plaque remains on the teeth for an extended period of time. This allows for more bacteria and debris to accumulate, resulting in further inflammation of the gums. Once this has occurred, the gum line will begin to recede allowing the bacteria to penetrate the jawbone. After this, the tooth will become loose and eventually fall out. Tartar can not only be above the gum line where it can be seen, it can also hide underneath.