The Self-adjusting File (SAF). Part 1: Respecting the Root Canal Anatomy—A New Concept of Endodontic Files and Its Implementation
- 1 April 2010
- journal article
- research article
- Published by Elsevier BV in Journal of Endodontics
- Vol. 36 (4), 679-690
- https://doi.org/10.1016/j.joen.2009.12.036
Abstract
To introduce a new concept, the self-adjusting file (SAF), and discuss its unique features compared with current rotary nickel-titanium file systems. The SAF file is hollow and designed as a thin cylindrical nickel-titanium lattice that adapts to the cross-section of the root canal. A single file is used throughout the procedure. It is inserted into a path initially prepared by a # 20 K-file and operated with a transline- (in-and-out) vibration. The resulting circumferential pressure allows the file's abrasive surface to gradually remove a thin uniform hard-tissue layer from the entire root canal surface, resulting in a canal with a similar cross-section but of larger dimensions. This holds also for canals with an oval or flat cross-section, which will be enlarged to a flat or oval cross-section of larger dimensions. The straightening of curved canals is also reduced because of the high pliability of the file and the absence of a rigid metal core. Thus, the original shape of the root canal is respected both longitudinally and in cross-section. The hollow SAF file is operated with a constant flow of irrigant that enters the full length of the canal and that is activated by the vibration and is replaced continuously throughout the procedure. This results in effective cleaning even at the cul de sac apical part of the canal. The SAF has high mechanical endurance; file separation does not occur; and mechanical failure, if it occurs, is limited to small tears in the latticework. The SAF represents a new step forward in endodontic file development that may overcome many of the shortcomings of current rotary nickel-titanium file systems.Keywords
This publication has 25 references indexed in Scilit:
- Influence of shaft design on the shaping ability of 3 nickel-titanium rotary systems by means of spiral computerized tomographyOral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2008
- A Comparative Study of the Effects of Two Nickel–Titanium Preparation Techniques on Root Canal Geometry Assessed by Microcomputed TomographyJournal of Endodontics, 2007
- A Comparison of Three Ni-Ti Rotary Instruments in Apical TransportationJournal of Endodontics, 2007
- Effect of Smear Layer on Sealing Ability of Canal Obturation: A Systematic Review and Meta-analysisJournal of Endodontics, 2007
- In vitro antimicrobial activity of sodium hypochlorite and chlorhexidine against selected single‐species biofilmsInternational Endodontic Journal, 2006
- Comparison of root canal preparation using RaCe and ProTaper rotary Ni‐Ti instrumentsInternational Endodontic Journal, 2004
- The capability of two hand instrumentation techniques to remove the inner layer of dentine in oval canalsInternational Endodontic Journal, 2003
- Clinical implications of the smear layer in endodontics: A reviewOral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2002
- Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: A comparative SEM investigationJournal of Endodontics, 1997
- Morphometric observations on the root canals of human molarsJournal of Endodontics, 1977