Cleaning and disinfection
- Last Updated on Tuesday, 29 November 2011 18:54
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The correct mechanical preparation of the root canal is an essential step in endodontic treatment. Diseased tissue and infected dentin are removed and the canal is prepared for cleaning and disinfection.
The root canal will be extended with special instruments until enough space is created for disinfecting irrigants and for a dense root filling. The preparation is done with hand instruments and / or motor driven rotating files.
Instruments for preparation
Modern file systems consist of a nickel-titanium alloy (NiTi) and are very flexible. They follow the course of the root canal better, but are prone to breakage. With stainless steel instruments a fracture is less likely. But as they are more rigid, there is a higher risk to alter the original course of the root canal or to perforate the canal wall.
For disinfection and cleaning of the root canal several irrigation is used to dissolve nerve tissue, to kill bacteria and to transport dentine debris out of the canal. The more completely they can penetrate into the root canal system and the longer they interact, the better it can be disinfected. Shaping of the root canal must therefore not only be just before the root tip, but also be dimensioned sufficiently.
Recent studies show that only about 60% of the root canal wall can be cleaned mechanically. This leaves a large amount of tissue and bacteria in the root canal and can cause the failure of treatment. With the help of rapidly oscillating metal tips (ultrasonic), irrigation solutions in the canal can be set in motion and reach inaccessible areas. The cleaning and disinfecting is thus improved.
More information is available in this video.
Preparation of Oval-shaped Root Canals in Mandibular Molars Using Nickel-Titanium Rotary Instruments: A Micro-computed Tomography Study
Frank Paque´, Prof. Dr. med dent,* Marc Balmer, med dent,* Thomas Attin, Prof. Dr. med dent,* and Ove A. Peters, DMD, MS, PhD†,
Journal of Endodontics Volume 36, Issue 4, April 2010, Pages 703-707
Necrotic pulp tissue dissolution by passive ultrasonic irrigation in simulated accessory canals: impact of canal location and angulation
A. Al-Jadaa,F. Paqué,T. Attin,M. Zehnder
International Endodontic Journal, Volume 42, Issue 1, pages 59–65, January 2009
The Influence of Preparation Size on the Mechanical Efficacy of Root Canal Irrigation In Vitro
Kenneth W. Falk DDS, Christine M. Sedgley PhD
Journal of Endodontics Volume 31, Issue 10, October 2005, Pages 742-745
Mechanical preparation of root canals: shaping goals, techniques and means
MICHAEL HÜLSMANN, OVE A. PETERS & PAUL M.H. DUMMER
Endodontic Topics 2005, 10, 30–76
Shaping ability and safety of five different rotary nickel-titanium instruments compared with stainless steel hand instrumentation in simulated curved root canals
Jörg F. Schirrmeister DDS, Christian Strohl, Markus J. Altenburger DDS, Karl-Thomas Wrbas DDS, Elmar Hellwig DDS, PhD
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology Volume 101, Issue 6, June 2006, Pages 807-813