34. Isolation of the operative field in endodontics – goals and purpose. Basic instruments and materials for isolation – types, characteristics, working techniques. Isolation of teeth with destroyed crowns – methods for approaching the problem.

Introduction

Isolation of the operative field means separating the teeth under treatment from saliva, gingival fluid, blood, breath moisture and the soft tissues, so that the field stays dry, clean, visible and accessible. It is a precondition for adhesive restorations and for aseptic root canal treatment, and it protects the patient from swallowing or inhaling instruments and the dental team from contaminated aerosol.

Why the field is isolated

• Moisture control: saliva or blood on etched enamel or primed dentin leaves a protein film within seconds and lowers bond strength; contaminated etched enamel must be re-etched. Moisture in zinc-containing amalgam during condensation causes delayed expansion.
• Retraction and access: lips, cheeks, tongue and gingiva are held away, and the field is better lit and seen.
• Protection of the patient: no aspiration or swallowing of files, clamps, burs, inlays or crowns, and no contact with etchant, debris or sodium hypochlorite.
• Infection control: the dam greatly reduces bacteria-laden aerosol and splatter (see topic 31).
• Asepsis in endodontics: salivary bacteria must not enter the root canal system.

Root canal treatment is always done under rubber dam; the European Society of Endodontology (ESE) quality guidelines make it the standard of care.