How to choose the right endodontic file？

There are many different types of endodontic files that can be used for endodontic eradication, root canal preparation and filling, so how do we choose the correct endodontic file? What is the difference between different endodontic files?

 

• What is the difference between K file and H file?

• Standardization of endodontic files

• In conclusion

 

What is the difference between K file and H file?

K files are made of rectangular or triangular blanks. Twist them to make the working end of the instrument spiral. The number of spirals or cuts may vary, but the number in the file is greater than the number in the reamer. Another difference is that the file is usually made of a rectangular blank, while the cross section of the reamer is triangular. Because of its fewer grooves and triangular cross-sections, K files are more flexible than K files. However, triangular K-shaped files with greater flexibility can now be used, as well as files with diamond-shaped cross-sections. The K file is used to enlarge the cutting action with longitudinal application and rotation, or more precisely, the tube through the combination of the two. The reamer can be used in the same way, but is most effective as a rotary cutting instrument. Recently, a new technology has been developed. With this technology, K files and files are processed with round wires instead of square or triangular blanks. This provides an interesting perspective on the stiffness, clarity and flexibility of the instrument. Another modification method that has proven to be clinically useful is to round the original sharp cutting tip of the K-type instrument. Instruments with non-cutting tips follow the root canal better than instruments with movable tips. Nonetheless, stainless steel instruments are still sufficiently rigid, so the curved catheter should be pre-curved to match the curvature of the root. The versatility of the K file has been greatly improved by introducing an instrument made of nickel titanium. This material is super-elastic, and instruments made of Nitinol have extremely high flexibility. With a non-cutting tip, they will conform well to curved canals. The canal of the instrument will be centered, and there is almost no visible perforation of internal bending band and external bending "elbow" or perforation that may occur with stronger instruments. Therefore, in curved canals, Niti taper file instruments have a real advantage due to their flexibility. Niti taper files are processed from round wire because they cannot be twisted due to the flexibility of the material. The size of the K file is 10-60. They are not as sharp and effective as matching tools made of stainless steel. However, due to their extreme flexibility, they will usually become the tool of choice. However, the smallest Niti Protaper Gold heat-activated instruments (10 to 20 sizes) are so flexible that they become ineffective and difficult to use. Therefore, good clinical practice is to use the smallest size steel files, because they are flexible enough, and then start using the 25-size nickel titanium instruments.

 

The H file is made of a round blank. The groove of the file is processed into a blank and formed into a continuous spiral like a screw. The angle between the groove and the long axis of the instrument is close to 90°. Therefore, the H file is designed for longitudinal file movement, not for rotating cutting tools. The Hedstrom file is by far the most effective manual instrument for root canal instruments. However, in order to achieve its full potential, it should be used in conjunction with a rotary cutting tool. Attempts have been made to improve the rotary cutting ability of the H file by reducing the flute angle of the instrument. However, this leads to reduced efficacy of the instruments when used in longitudinal filing motions, and these instruments have not yet been widely recognized.

 

Standardization of endodontic files

Today, K-type instruments and H files have been standardized. This means that all manufacturers should manufacture their device brands in accordance with the root canal device standards or specifications determined by the standardization organization. The number of the instrument is the same as the diameter (D1) of the tip of the instrument, expressed in hundredths of a millimeter. Therefore, the diameter of the tip (D1) of the 40 instrument is 40/100 mm, or 0.4 mm. The manufacturing quantity or size of standardized instruments is between 10-150. In sizes 10–60, there is one instrument for every 5/100 mm increase in D1, and 10/100 mm in sizes 60 and above. Type K instruments are also available in size 8.

 

In conclusion

In recent years, the quality, efficacy and standardization of endodontic files have undergone important changes. Dentists should choose the most suitable endodontic file according to the patient's condition. If you are looking for a high-quality endodontic file at a reasonable price, Osakadent Co.,Ltd. will provide you with the best products.