Canine Oral Resorptive Lesions
Canine Resorptive Lesions, or RLs, are holes that form in the tooth. They often start inside the tooth, from the pulp, and then break through to the outside of the tooth, but they may also be seen from the outside as pits or holes. The cause is, at this point, unknown, but we seem to be seeing more and more of them. In cats, we’ve seen an increase in the types of lesions over the past 25 years, and dogs seem to now be following suit. No one knows what has changed to cause these RLs to occur so frequently today. It may be a result of environmental changes, toxin exposure, a virus or a nutritional deficiency that we are unaware of. Unfortunately, they are currently being seen in as many as 60% of domestic cats, and if a cat has one RL there is a 72% chance the cat has or will develop additional ones. Because they are a new phenomenon in dogs, we don’t have comparable statistics yet. We hope they do not become as common in dogs.
In cats, resorptive lesions usually start in the enamel of the tooth, at the gum line. In the dogs we’ve treated, they seem to start deep within the tooth and then break through to the outside. The lesions progress, growing larger and deeper, and eroding more and more of the tooth. Once the enamel is eroded enough to expose the dentin layer underneath, or the pulp of the tooth becomes exposed, the tooth becomes painful. The affected tooth may fracture and eventually the crown of the tooth will be lost.
Most dog owners don’t notice problems in the mouth until the lesions are quite severe and their pet is in a lot of pain. Sometimes the hole in the tooth is on the tongue side and can’t be seen at all except under anesthesia, or it’s below the gum line or within the tooth and can’t be seen without dental x-rays. (This is why we recommend full mouth dental x-rays.)
Extraction of the affected tooth is the best course of treatment for many of these teeth. Attempts to repair these lesions with a filling rarely slows the destruction of the tooth. The lesion grows in size, the filling falls out, and the dog is in pain once again. Sometimes the roots of the tooth are damaged and difficult to remove. Teeth should have a bright white crown, and white roots with a dark line down the middle that contains the nerve and blood vessels. If the dental damage is severe or we think a tooth is salvageable with a root canal we will refer you to a veterinary dentist for more advanced treatment. Today’s state of the art pain medications along with a course of antibiotics help pets recover quickly from extractions, so they can return to pain-free living!