Attaining straight-line access into a canal is critical, as this will eliminate the need to place two points of maximum flexure on the file and will provide a better glide path to the apical third. Since cyclic fatigue and torsional stress can cause file breakage, placing minimal force on a file clinically will increase its time of usage before any failure occurs. They also noted that NiTi files rarely show any wear before breakage. In an in vivo study by Sattapan, 4 investigators found that torsional stress occurred 55.7% of the time, and cyclic fatigue occurred in 44.3% of the fractured files that were evaluated. Torsional stress occurs when the tip or any other part of the file is locked or bound within a canal while the shaft continues to rotate. Pruett stated that radius of curvature, angle of curvature, and instrument size play a role in placing cyclic fatigue on a file.1 Rotational speed (RPM) of the instrument has also been shown to increase the effects from cyclic fatigue-the higher the rotational speed, the time to file failure decreases significantly.
Cyclic fatigue is similar to taking a piece of wire and bending it back and forth until the wire breaks in two. Usually the file fractures at the point of maximum flexure-typically at the most curved portion of the root. Cyclic fatigue takes place when the file is freely rotating in a canal and flexes until fracture occurs. There are two primary factors that contribute to rotary NiTi file breakage: cyclic fatigue and torsional stress. However, while providing improved canal access, these types of flexible, mechanical files can be fragile and possibly break within the canal ( Figure 1). Rotary NiTi files are commonly used instruments for performing endodontic procedures.
#Edge endo rotary files price how to#
The purpose of this article is to discuss the causes of separated endodontic rotary NiTi files, explain how to prevent this problem from happening, describe the removal of a broken file, and discuss the prognosis for instances where the separated file cannot be removed. Understanding why and how endodontic file breakage occurs, including the two main factors that contribute to this type of incident, can help clinicians employ prevention strategies and overcome this predicament if it does occur. Separated rotary nickel-titanium (NiTi) files can also pose an increased risk of post-endodontic complications. Knowing that a portion of the endodontic file has broken off into the canal can be momentarily debilitating for the clinician. Of all the procedural problems that can occur when practicing dentistry, endodontic file breakage is one dilemma that not only can lead to extreme stress for the clinician, but can cause great anxiety for the patient as well. Midwestern University College of Dental Medicine
Technique and instrumentation considerations to reduce adverse events Preventing and Remedying Endodontic Rotary NiTi File Breakage
0 kommentar(er)
