True bacterial cavities are very rare in our animal patients. There are several reasons for this. First, the oral bacterial flora that live in our animals mouths are different than ours, and don't tend to cause the acids that cause cavities. Second, our animal friends rarely eat sugary or acidic foods that the bacteria that cause cavities use to create the acids that destroy our teeth. In addition, they don't have the occlusal (flat grinding surfaces) that we do. Finally, they don't live as long as we do, which decrease the time available for the bacteria to work.

The above being said, bacterial cavities (caries) do occur in dogs and very rarely in cats. The most common area is on the occlusal surface of the upper first molar. In addition, you can see them on the other upper molars, the back of the upper incisors, or anywhere else. The breed that is most affected is the German shepherd dog, although any breed can develop them.

Bacterial caries appear as dark brown to black discoloration on an area of tooth surface. Dentinal staining secondary to wear can appear like this as well, although it tends to be lighter in shade. The way to tell the difference is by feel. A sharp explorer when placed into a cavity will stick and resist removal. A worn area typically will not allow sticking at all. Wear spots that do not involve the root canal are generally not treated. An exception to this is if you decided to correct a malocclusion that was causing the wear. Treatment of bacterial cavities is similar to the fillings that you or I have had. The veterinarian will start by taking a dental radiograph to determine if the tooth is endodontically involved. If this were the case, then root canal therapy would be necessary prior to the restorative procedure. If the tooth appears vital, then using a dental drill, the veterinarian prepares the tooth for the filling. This is done by first outlining the edges of the future restorative, and then removing all the diseased tooth structure. The veterinarian will then place the filling. This could be amalgam (silver) or composite (white) depending on the nature and location of the cavity. If the cavity extends very close to the pulp cavity, then indirect pulp capping is indicated. If the pulp cavity is entered, then direct pulp capping is performed. If the tooth is severely diseased or endodontic therapy is not an option, then extraction can be considered.