Tooth Root Abscesses in a Shih Tzu

A tooth root abscess is caused by an infection in the root of a tooth. The dental pulp -- that is, the connective tissue, blood vessels and nerves in the center of the tooth -- is normally protected by the tooth's enamel covering. But the enamel can become damaged by an accident, a developmental abnormality or periodontal disease, which can damage the bony tooth socket. Damaged enamel allows bacteria to reach the pulp and cause an infection, which can lead to the development of an abscess -- a painful, swollen area filled with pus -- at the tooth's root tip or in surrounding tissues.

While Shih Tzus aren't especially prone to tooth root abscesses, the breed can have several tooth issues, some of which may raise the chance of the infection. Because the Tzu has such small jaws, for example, his teeth can be crowded, causing them to rotate to fit. Also, since an undershot bite is standard in the breed, your dog’s biting and chewing pattern can be off. Finally, a Shih Tzu sometimes retains a baby tooth or teeth until -- or even after -- the permanent one erupts, causing individual teeth to shift into abnormal positions. With rotated or displaced teeth or a misaligned bite, the chance of chomping an object in just the wrong way -- especially if the object is hard -- and damaging the enamel may be increased. Because a Tzu's teeth roots are relatively shallow, though, it's more likely the tooth will simply pop out when it meets with an exceptionally hard object rather than fracturing.

You'll probably not see any obvious signs of pain in your Tzu, although you might see him drop his food if he tries to chew on the affected side of his mouth or notice him eating or chewing on only one side. Your little guy might have bad breath and seem unwilling to chew on his toys; he may pull away when you touch his head, and you might notice him pawing at the affected side of his face or rubbing his face along the ground.

If the infection is not treated, the abscess will continue to grow. Depending on the location of the infected tooth root, you might see a swollen and inflamed area inside the dog's mouth -- on the gums around the affected tooth -- or on his face. In a case where the swollen lump is on your Tzu's face, you might mistake it for an insect bite or eye infection -- particularly if the infection is in the upper carnassial tooth, or fourth premolar, because its roots are located just below the eye.

Eventually the abscess will burst and typically drain through the fracture or fissure of the tooth. If the fracture becomes blocked, though, the drainage may occur through the tissue of the swollen area in his mouth or on his face and may be mistaken for a puncture wound. Even though the abscess has ruptured, the infection remains. It will continue to spread to the surrounding tissues and teeth unless it is treated. If the infection is not treated, it can damage the surrounding bone and teeth.

Your Shih Tzu's tooth root abscess, a very painful condition, needs to be seen by a veterinarian as soon as possible. Once there, your vet will likely order dental X-rays -- even if the tooth is obviously fractured, draining and easily diagnosed. These X-rays are necessary because not only do they help confirm the diagnosis, but they also make it possible for your vet to see if the infection has spread to surrounding bones and teeth, endangering their health. She may also run a blood test on your dog to check for more serious underlying medical conditions that may have contributed to or caused the abscess.

If the abscess has not yet burst, your vet will likely drain the fluid to eliminate any further infection. She will also probably prescribe antibiotics to control the infection, along with an anti-inflammatory or painkiller to help with the soreness. Although these efforts may relieve the symptoms, they don't address the underlying issue that caused the infection, which still needs to be treated. An abscessed tooth can be treated in one of two ways: a root canal or an extraction. Your vet will recommend the option she feels is best for your Tzu based on the severity of the abscess and the amount of damage to the tooth and surrounding structures.