Tartar is harmful in two ways. First, it serves as a place where bacteria can reside and multiply in the mouth. There is substantial scientific evidence that bacteria from tartar are absorbed into the blood stream and deposited in various organs. Heart and kidney disease often result. Second, tartar builds up along the gum line. As the tartar enlarges, it pushes the gums away from the roots of the teeth. Eventually, the teeth will loosen and fall out.
This photograph was taken of a 6 year old dog before and after a recent dental cleaning! Luckily after the tartar was cleaned up, the gums, roots, and teeth were all healthy enough and no extractions needed to be done. It is important to discuss your pet's dental health at their annual physical exam.