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 categ