Feline Tooth Resorption (FORL, cavities, resorptive lesions, cervical line lesion, neck lesion, carie)

FORLs (Feline Odontoclastic Resorptive Lesions) usually present clinically as very painful areas of granulation tissue extending into the crown surface of the tooth. Often they are not detected until the oral cavity is examined carefully under general anesthesia. Clinicians may be suspicious of FORLs when there is an area of gingivitis at the furca of multi-rooted teeth. The furca are the areas between the roots of multi-rooted teeth. Examination with a dental explorer at the gingival margin will reveal an "erosion" or "cavity" that feels rough. A normal furcation will be smooth since it is covered with cementum. If the resorption has progressed through the entire tooth, the crown may be missing or partially missing as the enamel of the crown is undermined by resorbed dentin. If the defect is exposed to the oral cavity, these lesions can be very painful for the patient and even under general anesthesia, the cat may "chatter" when the tooth is touched with any instrument. Coronal lesions may be covered by granulation tissue which may be interpreted only as inflamed gingiva. Resorptive lesions with no communication to the oral cavity do not seem to cause pain. It is only when the crown fractures or a lesion progresses coronal to the alveolar bone that it becomes evident clinically and is painful.

Dental Xrays are very important in both diagnosing and treating FORLs. An early shallow lesion, may be treated with a restoration. This may not be a "cure", but may allow the cat to have the function of the tooth for months or years. If the resorptive lesion is progressed, extraction is the treatment.