Periodontal disease occurs when the bone and gum attachment around your teeth are damaged. This can happen to one tooth or to all your teeth. One cause of this disease is bacteria. When unbrushed food collects around your gum line, it forms plaque and bacteria that can build up around your gums. The gums then become inflamed and swollen similarly to having an un-removed splinter. In time, un-removed plaque forms tartar, a hardened formation removable only by your dentist. If tartar remains around the gum line, it creates an infection. The gums attached to your tooth, as well as the bone, are damaged. This creates a pocket making cleaning more difficult. If its not treated by your dental hygienist, it will continue to worsen.
The other cause of periodontal disease is mechanical damage to your teeth from grinding or clenching. This consistent trauma irritates the bone causing it to deteriorate around the tooth.
Over time, if any source of the disease is not removed, there is potential for bone and gum loss that can lead to tooth mobility and eventual loss. The earlier it is detected, and the source removed, the less time and money it takes to treat.