The document discusses the importance of isolating the operative field during dental procedures. It outlines the components of the oral environment that need to be controlled, including saliva, tongue, lips, cheeks and gingiva. Methods of isolation include direct techniques like cotton rolls, cellulose wafers and isolite mouthpieces as well as indirect methods like high-volume evacuation and saliva ejectors. Isolation provides benefits like a dry, clean operating field which improves visibility and infection control, as well as increased comfort for patients and efficiency for operators. Local anesthetics, anti-sialogogues and other drugs can also help in isolating the field.