The oldest quotation is the Standard, introduced by Engel. It has disadvantages such as chances of losing working length and ease of tinning, zipping or perforations. The posterior step technique, also known as endoscopic or series root canal preparation, was first described by Mulaney, and is divided into two stages: during the first stage the working length is determined and then the apical part of the root canal is precisely shaped by a 25 K file up to the working length; During the second stage, the remaining part of the root canal is prepared manually or with rotating devices.
This procedure has some drawbacks, such as iatrogenic errors such as apical translocation, i.e. using instruments too short or too long, such as those working in the modified backstep, or obstructive debris build-up, which results from the negative backstep method developed by Torpengad. All these procedures, and those that follow, repeated ground work with recapitulation with the main apical file, mean that we use a small file (usually 10 or 15) up to the apical foramen. Crown down is a procedure performed by a dentist who prepares the beginning of the coronal part of the root canal after ensuring the patency of the entire root canal with the main apical file.
There is also a “hybrid” procedure that combines the “posterior step” and “crown-down”: after ensuring the patency of the root canal, the coronal third is prepared manually or by means of a Glideen Gates drill, then the working length is determined, and finally the apical part is formed using the technique back step. Double flush is a procedure introduced by Vava in which the root canal is explored using a small file. The root canal is prepared by the crown-down method using a K-file and then by the “back-step” method with an increment of every 1 mm the file sizes are increased.
Another book, Endodontics” by prof. Castellucci from Florence, describing early coronal segment enlargement, corroborated by A. Clifford Ruddell of Santa Barbara. This technique is the same one that Dr. Francesco Retano of Catanzaro previously described as the “three times technique”. However, according to this complex procedure the apical root canal is prepared in the first place after checking the working length by means of an apical positioning device; It is then progressively enlarged by perforating the gluteal gates (coronal and medial two-thirds only); The third time the dentist “reaches the apex” and, if necessary, prepares the apical foramen with a 25-volume K file. The last stage is divided into two refining passes: the first one is an instrument with a 1 mm zigzag, and the second one with a 0.5 mm zigzag.
From the early 1990s power-driven tools were gradually introduced; These are: the ProFile system, the Greater Taper file (or “GT file”), the ProTaper file (praised by Castellucci), and others such as Light Speed, Quantec, K-3rotary, Real World Endo, Hero642.
Preparation using ultrasonics is also described by Gargs, but the author doesn’t have any experience, so he won’t talk about it.
