If you have a cat, you may have heard one of us refer to our hated friends called FORLs. FORLs, which stands for feline oral resorptive lesions, are a relatively common dental finding in our mature kitties and boy, do they frustrate us! These lesions are similar in appearance to human cavities, but form in an entirely different manner. Cavity formation is ultimately due to bacteria. With feline resorptive lesions, a type of cell, called an odontoclast, is more active than normal resulting in destruction of the tooth.
The resorptive lesions typically start as very small pinpoints and can be found on any part of the tooth. Often times, they hide out along the gum line or underneath the gum line making them nearly impossible to find without dental x-rays. For example, the x-ray below is of a cat that came in for a dental procedure. His lower canine teeth both looked healthy during his oral exam. However, when we took x-rays of his lower teeth, I saw a significant resorptive lesion under his gum line. Because of this lesion, this tooth ended up being extracted. If we had not taken x-rays of his teeth, this lesion would have been missed and the poor kitty would still be in a significant amount of discomfort. Continue reading