When gingivitis progresses, it develops into periodontitis, a condition in which the gums and bone that hold the teeth in place can be severely weakened. The bacteria on the teeth release toxic substances that harm your gums and cause them to become infected. The infection and the inflammation that result when your body attacks the bacteria can degrade your gums and the bone in your jaw even further. You may have exceptionally swollen, painful gums that are likely to bleed. If left untreated, periodontitis can lead to tooth loss.