A clear and very complete answer to this question can be found at the American Academy of Periodontology website. It begins this way:

“Periodontal (gum) diseases, including gingivitis and periodontitis, are serious infections that, left untreated, can lead to tooth loss. Periodontal disease can affect one tooth or many teeth. The main cause of periodontal disease is bacterial plaque, a sticky, colorless film that constantly forms on your teeth. However, factors like the following also affect the health of your gums.”

It then discusses the following contributing factors:

-Smoking/Tobacco Use
-Puberty, Pregnancy and Menopause in Women
-Clenching or Grinding Your Teeth
-Other Systemic Diseases
-Poor Nutrition and Obesity

If you relate to any of these please go to: