They start as small defects in the tooth
structure just
under the
gum line, and progress to painful invasion of the tooth by cells that gradually remove tooth
structure and replace it with bone.
Some practitioners incorrectly treat these teeth by simply cutting off the visible part of the tooth, leaving the root
structures in place
under the
gum line to be hopefully resorbed over time.
As in humans, the presence of bacteria causes bad breath (bacteria stinks), and the accumulation of tartar causes irritation and inflammation to the
gums around the dog's teeth (gingivitis,
under the form of red, swollen
gums), which in turn may lead to periodontal disease (the loss of the connective tissue fibers, ligaments and bone surrounding the teeth and responsible for supporting them) and eventually tooth loss due to gradual loss of supporting
structure — see photo, something known as gingival recession.