Hyflex CM and EDM Files: Revolutionizing the Art and Science of Endodontics

Successful Endodontic therapy is based on cumulative results of complete debridement and disinfection of root canal system, followed by a three dimensional obturation [1]. However, certain anatomic complexities such as very fine canals such as those commonly encountered in geriatric cases and extremely curved canals can pose a real challenge to the treating dentist [2]. Inability to completely negotiate the entire root canal up to its physiologic terminus, often results in endodontic failure [3]. Rotary Endodontic Instruments brought a paradigm shift in the field of Endodontics [4,5]. However, as the use of these fast cutting Ni Ti Files progressed across the globe, the advantages were paralleled by the limitations and drawbacks [6]. The instrument related procedural errors such as ledge formation, transportation, perforations etc. became increasingly common, leading to major concerns over the use of aggressive rotary endodontic files. This led to the researchers’ world over to rationalize the possible cause of such mishaps. Eventually a concept emerged which revolutionized the technology of rotary endodontic files, which was based on ‘Controlled memory’ in contrast to the classical ‘Shape memory’ one. A new Nitinol rotary instrument files with controlled memory (Hyflex® CM, Coltene) was introduced which was machined from a wire (termed CM-wire) previously subjected to a proprietary, novel, thermomechanical processing procedure. Clinical and experimental studies have indicated that these new Hyflex® CM rotary instruments have outstanding clinical fatigue resistance [7]. The Controlled memory effect helps the file to retain the shape of the canal even when it is out of the canal (Figure 1). This property is responsible for avoiding procedural errors such as ledge formation, transportation, perforations etc. the extreme flexibility and lesser taper of these files make them very advantageous in curved canal cases. Of late, another major transformation has happened in file technology which has taken the endodontics to a next level. This has been introduction of EDM files (Figure 2). EDM stands for Electrical Discharge Machining. This is a unique process of making the files process using electric discharge machining. Work pieces are machined in the EDM manufacturing process by generating a potential between the work piece and the tool. The sparks generated in this process cause the surface of the material to melt and evaporate. This creates the unique surface of the new Niti files and makes the Hyflex EDM files stronger and more fracture resistant [8]. This entirely unique combination of flexibility and fracture resistance makes it possible to reduce the number of files required for cleaning and shaping during root canal treatment without having to compromise preservation of the root canal anatomy. Volume 5 Issue 7 2016