Feline Oral Resorptive Lesions (FORL) or Odontoclastic Resorption in Cats
In cats, the odontoclast, a type of cell, can cause the tooth structures to disintegrate. Initially, the odontoclast cells attach to natural cavities in oral tissue, with the purpose of reabsorbing the non-permanent, or deciduous teeth. As resorption continues, complications may develop, as bone-like tissue covers the problem area. Over time, ligaments and bones that hold teeth in are affected as well.
Feline odontoclastic tooth destruction (resorption) is extremely common. Roughly half of all cats over five years of age have at least one instance of it, and those numbers increase with age. Certain breeds seem to have a tendency towards the condition, including Abyssinians, Asian shorthairs, Persians, and Siamese.
Symptoms and Types
The most obvious indications of the condition are drooling, difficulty chewing and bleeding from the mouth. Behavioral changes may accompany the condition as well; cats may become aggressive or may avoid others. While feline odontoclastic tooth resorption can occur in any tooth, it is most often seen in the back teeth.
A surface exam may provide evidence of a problem, but generally a deeper exam performed under general anesthesia is necessary. During this exam, the lesions are probed and the stage of the resorption is determined by the depth of the probe. Stage 1 signifies a minor condition. Stage 2 implies moderate loss. Stage 3 has major tissue loss, where the loss is severe enough to expose the root of the tooth. Stage 4 is similar to stage 3, except that at this stage, both the top of the tooth (crown) and the root are affected. By stage 5, there are only spotty remnants of hard tooth tissue, and the remains of the tooth have been covered by the gums.
No specific cause of feline odontoclastic tooth resorption is known. There are likely several factors that contribute to the problem. A mineral imbalance is one possibility. Other causes being investigated include increased reactivity to dental issues, such as plaque.
Other possible causes of the symptoms are a severe disease of the mouth (lymphocytic plasmacytic stomatitis syndrome) or recession of gums coupled with root exposure (generally considered a different type of resorption). X-rays of the mouth are taken to ensure correct diagnosis.