This document discusses chronic periodontitis, the most common form of periodontitis. It is defined as an infectious disease resulting in inflammation and destruction of the tissues supporting the teeth. The key clinical features are plaque, gingivitis, attachment loss, bone loss, and inflammation. Chronic periodontitis is considered a site-specific disease where inflammation and bone loss occur at specific sites due to local plaque accumulation. The severity is classified as slight, moderate, or severe based on the amount of attachment loss. Risk factors include poor plaque control, systemic diseases, environmental/behavioral factors like smoking, and genetics. Treatment involves improving oral hygiene, nonsurgical treatments like scaling and root planing, and sometimes surgery.