Dental Corner: How to detect and treat feline odontoclastic resorptive lesions - Veterinary Medicine
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Dental Corner: How to detect and treat feline odontoclastic resorptive lesions


The earliest lesions, confined to the root cementum, are not painful. If the resorption spreads apically, there can be marked destruction of root structure without pain. However, if the lesion progresses coronally and exposes the dentin to the oral cavity, pain is definitely present. Secondary bacterial contamination and inflammation can affect the surrounding periodontal tissues as well. In other words, lesions you can probe or visualize are painful. Lesions you cannot probe but can see on radiographs are probably not painful.

Clinical signs associated with FORLs include anorexia, drooling, refusal to eat the hard portions of the diet, and malaise. The most common clinical presentation in cats with resorptive lesions may be no (overt) sign of pain. If a cat has an FORL in one tooth, it is safe to assume that the cat is at a high risk for other teeth to eventually become affected.


Dividing a disease process into categories is helpful when it can guide treatment decisions. FORLs can be divided into three categories for this purpose: 1) normal-appearing teeth with radiographic evidence of an FORL, 2) teeth with clinical lesions and minimal radiographic root pathology, and (3) teeth with clinical lesions and radiographic evidence of root resorption and ankylosis (fusion between the root and alveolar bone).

Normal teeth with radiographic evidence of FORLs

Teeth that have been identified by radiography with evidence of FORLs but with no abnormal findings on oral examination (and, therefore, not painful) do not need to be immediately extracted. However, these teeth will probably progress to clinical disease at some time in the future. Conservative management (monitoring) is an option, but is incumbent upon a six-month recheck including anesthetizing and re-radiographing. And with monitoring, the prognosis is guarded. Alternatively, the affected teeth can be preemptively extracted.

Clinical lesions and minimal radiographic root pathology

Figures 4A & 4B. The mandibular left molar (#309) has gross evidence of an FORL and a probable defect (4A). The dental radiograph (4B) shows a resorptive (external) lesion of the mesial root centered at the cementoenamel junction but minimal root resorption. Additionally, horizontal and vertical bone loss are evident. Both roots should be surgically extracted intact.
If a tooth is clinically affected with an FORL but the radiographs show minimal evidence of root resorption (Figures 4A & 4B), extract the tooth. Extraction of feline teeth is accomplished by using proper surgical technique and high-speed dental equipment. Creating mucoperiosteal flaps and removing buccal cortical bone facilitate this procedure. Section multirooted teeth into their individual crown-root components, elevate the roots individually, and extract them routinely. If root fracture occurs, surgical root tip retrieval will be required.4,5


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