NiTi mechanical endodontic file

Endodontic file: The essential tool for root canal treatments

The endodontic file is an indispensable instrument in the field of dental instrumentation, particularly during root canal treatments. It plays a key role in the cleaning and preparation of root canals in order to eliminate infections and restore dental health.

The endodontic file and the root canal

The endodontic file is specially designed for root canal treatment procedures, also known as endodontic treatment. It is manufactured from stainless steel or nickel-titanium (NiTi), offering excellent torsional resistance and great flexibility. NiTi files are particularly valued for their elasticity and their ability to conform to the curved shapes of root canals.

Root canal treatment is a dental procedure carried out to treat and save a tooth whose dental pulp, inside the tooth, is infected or damaged. The dental pulp is composed of living tissues, such as nerves, blood vessels and pulp cells, and its role is to nourish the tooth and transmit sensations of heat, cold and pain. When the pulp is infected, this can cause intense pain, increased sensitivity and inflammation.

Root canal treatment is generally carried out in several stages, and the use of the endodontic file is essential to achieve the objectives of this procedure.

Endodontic files have a colour code that allows you to identify them easily. The colours allow you to identify the model, the diameter and the taper as a percentage.  

Difference between a continuous rotation file and a reciprocating rotation file:

A closer look at our endodontic file, which also features variations in the rotation modes used during its operation. Here are the main characteristics of each method:.

1. File for continuous rotation :

The continuous rotation file is effective for quickly removing pulp tissue and preparing root canals. It requires adequate irrigation to eliminate debris and keep the temperature under control. It is often used in complex root canal treatments or when rapid removal of material is required.

As its name suggests, the rotation is continuous in a single direction, the clockwise direction when viewed from above the bur. The file can be used with a contra-angle «endodontic with green ring» at very low rotation speed (+/- 300 rpm, often with a ratio of 64:1 or 128:1), mounted on a standard micromotor fitted to the dental chair, or on an «endodontic motor» — a motor dedicated to endodontics — which manages the rotation speed and the torque applied to the file.

At a certain level of pre-programmed torque on the motor, in order to protect the file from potential breakage inside the canal, the motor will stop the rotation or, more commonly, reverse the direction of rotation to «free» the file.

2. File for reciprocating rotation: 

This file uses a so-called «reciprocating» rotation movement. Normally, this file can only be used with endodontic motors that manage alternating rotation at defined angles.

Normally, and viewed from above, the endodontic motor drives the file in a rotation of 150° counter-clockwise, then 30° clockwise, resulting in a component of 120° counter-clockwise per cycle, and 360° (one full turn in three rotation cycles).

So-called reciprocating files are «cut» in such a way that they are designed to «work/drill» counter-clockwise, and «evacuate» drilling debris clockwise. The advantage of this type of operation is that the file is much less likely to become «stuck» in the canal and break… The file also tends to generate less heat, as it experiences less friction, and/or for a shorter duration.

However, this type of operation implies that a so-called reciprocating rotation file cannot work with a motor that rotates clockwise (standard green contra-angle on the chair micromotor), as its cutting capability is in the opposite direction. They can therefore only work with an endodontic motor.

This type of file is supported by the vast majority of endodontic motors.

3. File for reciprocating rotation, new generation, «working» in the clockwise direction.

The vast majority of so-called "reciprocating rotation" files are designed to work with alternating rotation at different angles, with the main angle being counter-clockwise. For example, a file must operate at its best performance with a rotation of 150° counter-clockwise followed by 30° clockwise. Thus, with each cycle, the file "rotates" 120° counter-clockwise (150 - 30), and therefore in three cycles the file completes a full turn.

The working part of the file operates in the counter-clockwise direction. The file "works" at 150° and "evacuates" at 30°. This type of file is the first type of reciprocating rotation file to have been developed, and therefore all endodontic motors support this type of file.

This type of file only works counter-clockwise, unlike continuous rotation files which work clockwise.

A new type of "reciprocating" file has therefore appeared to address this particular feature and work in the clockwise direction. These are files still designed to operate in reciprocating rotation, but with a rotation of 150° clockwise followed by 30° counter-clockwise.

These new-generation files can therefore work in both continuous and reciprocating rotation.

To date, there are few endodontic motors that manage reciprocating rotations where the clockwise angle is greater than the counter-clockwise angle. Therefore, make sure to find out about your motor's ability to manage this type of reciprocating rotation before purchasing your equipment.

Comparison between a dental bur and a NiTi endodontic file:

On a more anecdotal note, there is a confusion online between the terms dental bur/file and endodontic file. Although both of these files are used in dentistry, they differ considerably in their function and use. A dental practitioner will not make a mistake in their use, but for all preventive purposes, here is a brief comparison of the 2 types of files:

• Dental bur or endodontic file: A dental bur is primarily used during routine dental care to remove dental plaque and tartar, as well as to polish tooth surfaces or prepare a tooth for prosthetic treatment…
• NiTi endodontic file: It is specifically designed for root canal treatments, enabling the cleaning, shaping and preparation of root canals for obturation.

Find in this category the endodontic file that meets your needs. This comprehensive comparison is intended to help you select the file of your choice. Do not hesitate to contact our team if needed.