Sometimes the disease is rapid. However often the disease takes a long time to develop. The linked documents provide some information about gingivitis and periodontitis and the material also show the effect of successful t reatment. The pocket around the tooth, a perfect hiding place for the bacteria. Left undetected, never or seldom cleaned, then the bacteria thrive and multiply.
Bacteria cause the inflammation.
The inflammation gradually destroy the tooth attachment. Severe periodontitis in a 50 year old male. He has not noted his periodontitis but have observed that the gumline has receded onto the roots on several teeth. He suffers from malodor and his family has complained on that he has a bad breath. Bacteria accumulate on the tooth surface and substances are produced which enter the gum and cause an inflammation.