One of the most common problems we see with kitty’s mouths is a very painful condition called resorptive lesions. Like ours, cat teeth have a center chamber called the pulp cavity that contains nerves and blood vessels. The pulp cavity is protected by a calcified tissue called dentin and an outer layer of enamel.
Resorptive lesions are caused by the body essentially breaking down the protective layers of dentin and enamel exposing the very sensitive nerves. Despite ongoing research, it is unknown why cats develop these lesions. Teeth from cats from the Middle Ages have been found with resorptive lesions, however, so it is problem that has affected cats for a very long time. Even though these lesions look very similar to cavities there is a key difference: the destruction of the tooth that occurs with a cavity can be stopped by removing the diseased part of the tooth and replacing it with a filling.
Unfortunately, studies have shown that filling these lesions in cats does not stop the process and does not relieve the pain associated with them. Once a resorptive lesion has started to develop the best option is to extract to affected tooth or teeth.