The SAF System is a shaping and cleaning system designed for minimally invasive endodontic treatment.

 The system consists of a self adjusting file operated with a special RDT handpiece-head and an irrigation pump (either the VATEA pump or the all-in-one EndoStation unit, see below) that delivers a continuous flow of irrigant through the hollow file. Because the file is built as a lattice-walled cylinder , no pressure is generated within the file; any small pressure that is generated by the pump to deliver the irrigant through the tube is eliminated the moment the irrigant enters the file.

The Self-adjusting File (SAF)

The SAF is the first file that does not have a solid metal shaft.

The file is designed as a hollow tube, the walls of which are made from a thin nickel titanium lattice  with a rough outer surface . The file has an asymmetrically positioned tip , located at the wall of the tube as opposed to the symmetrically centered tips found in all conventional nickel titanium rotary files. 

The SAF system is extremely flexible and also extremely compressible, so that a 1.5-mm diameter SAF may be compressed into a root canal in which only a #20 K file could previously be inserted . This compressibility also enables the file to adapt to the cross-sectional shape of the canal. When inserted into an oval canal with a 0.2-mm mesiodistal diameter, a 1.5-mm SAF will be compressed mesiodistally and thus spread buccolingually as far as 2.4 mm  This will occur even if the operator is not aware that the canal is oval; hence, the name “self-adjusting file”. Naturally, such a flattened file cannot rotate in the canal and is therefore operated with in-and-out vibrations created by the RDT handpiece-head.

Current rotary file systems are effective tools. Nevertheless, they have two main shortcomings:

1- They are unable to effectively clean and shape oval canals and depend too much on the irrigant to do the cleaning, which is an unrealistic illusion

2- They may jeopardize the long-term survival of the tooth via unnecessary, excessive removal of sound dentin and creation of micro-cracks in the remaining root dentin.

The new Self-adjusting File (SAF) technology uses a hollow, compressible NiTi file, with no central metal core, through which a continuous flow of irrigant is provided throughout the procedure. The SAF technology allows for effective cleaning of all root canals including oval canals, thus allowing for the effective disinfection and obturation of all canal morphologies. This technology uses a new concept of cleaning and shaping in which a uniform layer of dentin is removed from around the entire perimeter of the root canal, thus avoiding unnecessary excessive removal of sound dentin. Furthermore, the mode of action used by this file system does not apply the machining of all root canals to a circular bore, as do all other rotary file systems, and does not cause micro-cracks in the remaining root dentin. The new SAF technology allows for a new concept in cleaning and shaping root canals: Minimally Invasive 3D Endodontics.

Rotary nickel titanium (NiTi) files were first introduced clinically in 1993. They were a major turning point and represented a real paradigm shift in endodontics.

New designs have been introduced over the years, attempting to make these instruments more efficient, more flexible, and safer in terms of file separation.

 Recently, innovative metallurgy and reciprocating movement were combined to allow for the creation of “single file” systems, such as Wave One (Maillefer-Dentsply, Ballaigues, Switzerland) and Reciproc (VDW, Munich, Germany).

Both new and traditional rotary file systems utilize the same basic concept. In all currently used systems, the files consist of a solid central metal shaft with a rotating blade and flutes to either contain or carry off the cut material. As long as the canals are simple, straight and narrow, with a round cross-section, such instruments are likely to achieve the goals of root canal instrumentation and shaping. In such canals, instrumentation of the canal to the shape of the file may be sufficient and result in adequate cleaning of the canal.

Nevertheless, rotary instruments, both new and old, may fail to meet the challenge of either oval or curved canals.

This need currently remains unmet due to (a) the challenge of three-dimensional (3D) cleaning and shaping of oval and curved canals, (b) the microbiological challenge of infected oval canals and (c) the challenge of 3D obturation of oval canals. Above and beyond all of these, (d) the challenge of maintaining the integrity of the remaining radicular dentin, was recently recognized. All rotary file systems tested so far create micro-cracks in the radicular dentin in a high percentage of treated roots, which may predispose them to vertical root fractures. This last challenge applies to roots with round cross-sections as well.

The targets of endodontic treatment are the complete cleaning, adequate disinfection, and effective obturation of the root canal. Each of these challenging targets is critical for the success of endodontic treatment. 

The SAF is used as a single instrument to achieve complete 3D root canal cleaning and shaping in a minimally invasive way. Its hollow shape allows for the continuous flow of irrigant through its lumen to achieve superior disinfection.

The SAF 1.5 mm is designed for canals with an initial apical size of ISO 20-35.

The SAF 2.0 mm is designed for use in wider canals with an initial apical size of ISO 35-60 commonly found in retreatments or younger patients. The SAF 2.0 mm may also be used in wider canals (≥#70), but would then require the dentist to pay attention to the possible rotation of the file inside the canal.

👆Cleaning and shaping

👆Root canal treatment , basic procedure