Pyorrhea, also known as periodontitis, is a serious gum infection caused by bacterial plaque that leads to damage of gums, ligaments and bone if left untreated. It causes symptoms like bleeding gums, bad breath and loose teeth. There are different types including chronic and aggressive periodontitis. Risk factors include poor oral hygiene, smoking, certain illnesses and genetics. Prevention involves brushing teeth twice daily, regular dental visits, and proper hygiene through scaling and root planing.