When Good Teeth Go Bad

This article is posted with the permission of the American Kennel Club.
© 2007 The American Kennel Club, Inc.

From the pages of the FEBRUARY 2007 KC GAZETTE
By Jeff Grognet, DVM

When was the last time you had a good look in your dog’s mouth? If he’s over 3 years old, there is a 75 percent chance that he has dental disease—plaque, tartar, and inflamed gums. Besides causing bad breath and tooth loss, infection in the oral cavity can spread to vital internal organs. Oral disease can shorten your dog’s life.

Small-breed dogs are prone to tartar accumulation when very young, which results in the loss of many teeth by the time they’re 10 years old. The problem begins with the formation of a thin, soft film of food and bacteria—plaque—on the teeth. If left undisturbed, plaque eventually mineralizes and hardens to form tartar.

Meanwhile, bacteria in the mouth cause gingivitis (inflammation of the gums) and recession of the gum-tooth attachment. The natural depression in the gum next to the tooth is called the sulcus, and a healthy sulcus is, at most, a few millimeters deep. But in dogs with severe gingivitis, gum attachments can break down to depths as great as 15 millimeters. As the gum recedes, there is a corresponding breakdown of supporting bone. The tooth becomes abscessed and falls out.

An abscessed small incisor, with just one root, is lost very quickly because it has so little holding it in place. In contrast, a large carnassial tooth, such as the upper fourth premolar (fourth tooth behind the upper canine tooth), has three roots and takes much longer to fall out. Each of the roots must become loose before the tooth is released from its socket.

Larger breeds, such as German Shepherd Dogs, don’t collect as much tartar on their teeth so they are not as prone to gum recession. Though they can have problems with gingivitis and tartar, they are much more likely to experience tooth fracture. The tooth most commonly damaged is the upper fourth premolar (PM4). When the outer surface of PM4 is cleaved off, the pulp cavity is exposed. Ultimately, bacteria invade and travel up to the end of each root, creating an abscess. This pus pocket causes significant pain.

Whether a dog has an abscessed fractured tooth or tartar and gum disease, the bacteria in his mouth can penetrate his gums and migrate via the bloodstream throughout his body—the heart, kidneys, and liver are particularly susceptible to invasion by oral bacteria.

In the heart, bacteria readily settle on the delicate valves, causing scarring that leads to valvular leakage. Eventually, dogs with leaky valves develop congestive heart failure—an inability of the heart to pump enough blood forward.

When bacteria land in the kidneys, they stimulate the formation of tiny abscesses that cause deterioration of kidney function. Over time, these changes result in chronic renal failure.

Many dogs with dental disease have elevated liver enzymes. In this case, the bacteria have migrated to the liver, causing infection and tissue damage.

How can you help your canine friend live a longer life? Look in his mouth regularly. If his gums are cherry red, he has gingivitis. If you smell foul breath, he has a bacterial infection—it might just be from plaque, but it could be from an abscessed tooth. Remember that it’s difficult to assess your dog for oral pain. In rare circumstances, you may notice that he refuses a hard treat or that he chews on only one side. But in most cases it isn’t until a problem tooth is removed and the dog exhibits increased vitality that an owner recognizes the agony the dog has been in.

When you detect a problem in your dog’s mouth, have him examined by your veterinarian. If he has minimal gum recession, a proper cleaning both above and below the gum line can help the gum reattach. If you wait too long, the pockets become deeper (more than three millimeters), the roots become exposed, and tooth loss becomes an inevitable fact.

Veterinarians see the consequences of mouth infections daily—abscessed teeth, gingivitis, as well as weak hearts, failing kidneys, and stressed livers. Don’t ignore bad breath, discolored teeth, or red gums in your canine friend. Your dog needs diligent oral care from both you and your veterinarian to live a full and healthy life.

Jeff Grognet is a veterinarian with a practice in British Columbia, Canada.

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Last Updated: 02/08/2007, 2:29 pm