In modern dentistry, reliable endodontic treatment is increasingly important. Many procedures have been developed in recent years in order to improve the treatment possibilities. For instance, the laser-supported disinfection of root dentin has brought a major advance. Whatever technique is applied for infection control and the achievement of a tight root canal seal, the indispensable basis for successful endodontic treatment is a dependable root canal preparation. In general, root canal preparation means accessing the root canal system and performing shaping and cleaning of the canals. Nowadays, it is recommended to shape and clean with a combination of chemical and mechanical methods. Another important part is the disinfection protocol using various irrigations, medication, and ultrasonic or laser devices. To use these methods, it is necessary to obtain access to the root canal system and perform a mechanical root canal enlargement. This article presents the preparation of an ideal access cavity and the general working principle of mechanical root canal treatment with nickel-titanium instruments and the crown-down technique. Finally, guidelines for safe working conditions with the presented technique are given.
Keywords: root canal preparation, mechanical, crown down, access, nickel-titanium files