Dec 27 2013

Feline Oral Resorptive Lesions

Odontoclastic resorptive lesions (ORL) are a very common problem for our patients. Although rarely seen in most species, we see these lesions in more than 50% of our feline patients. Any tooth can be involved, but the premolars and molars are most commonly affected. The pattern is usually symmetrical. Signs of this condition can include decrease in appetite, preference for soft food, failure to chew food, oral odor, drooling and a cat’s reluctance to allow his/her mouth to be touched.

The condition begins at the tooth root and gradually moves from the outside of the root into the inside of the tooth and up to the crown. The root surface is replaced by bone-like tissue. Eventually, the enamel is reabsorbed and a hole in the tooth is apparent. It is not until this point in the disease that the lesion can be seen on visual exam. The tooth is so weakened that even chewing can cause the tooth to fracture and leave the root exposed.

These lesions are painful and the best treatment is extraction. The extent of the extraction is based on radiographic changes. ORL are not the same as cavities commonly found in people. Those lesions have never been described in cats.

The cause of this condition is unknown. There is currently no treatment to prevent the development or progression of this disease.

The goal of treatment is to prevent pain. In the early stages of this condition it does not appear to be painful. In later stages when the inside of the tooth is exposed to the oral cavity, discomfort is likely.


  • Conservative — If the lesion is only visible radiographically and is not painful, then monitoring may be the only treatment needed.
  • Extraction — Teeth with ORL are difficult to extract. The root is resorbing and being replaced with bone and in some areas the bone and the tooth are fused. Many times, open, surgical procedures are needed to assure successful extraction. Radiographs are essential to determine the appropriate treatment.
  • Coronal amputation — when the root has been extensively resorbed and it is not possible to remove all the tooth substance, the removal of the crown of the tooth may be the best treatment. If this treatment is chosen, radiographs are used to ensure that the root is resorbing and that healing is uneventful.

Regardless of the treatment plan the goal is to make every patient comfortable. Hopefully in the future, the cause of this condition will be found and prevention will be possible.

Source: Cat Spay of Santa Fe

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