Many cats get painful lesions at the gum line that invade the teeth. The lesions are referred to as feline odontoclastic resorptive lesions (FORLs). Recent research indicates that in cats over 5 years of age there is a 72% chance he or she may have a FORL. These dental resorptions called cat cavities or neck lesions can occur in any tooth.

The most commonly affected teeth are the lower premolars. Unlike cavities in humans, which are the result of bacterial enzymes and acids digesting the teeth, the cause of FORLs are unknown. Specifically, cells known as odontoclasts are found in the defects causing the tooth structure to dissolve. What triggers this reaction has not been determined for certain but a reaction to plaque on the teeth seems to be the major factor.

Cats affected with FORLs may show hypersalivation, oral bleeding, or have difficulty chewing. A majority of affected cats do not show obvious signs but are in pain. A cotton tipped applicator applied to the suspected FORL causes pain with jaw spasms when the FORL is touched.

The treatment for advanced FORLs is extraction of the affected tooth and/or roots.