The purpose of this study was to investigate the application of nondestructive testing in cyclic fatigue evaluation of endodontic ProFile nickel-titanium (NiTi) rotary instruments. As-received ProFile instruments were made to rotate freely in sloped metal blocks by a contra-angle handpiece mounted on a testing machine. Rotation was interrupted periodically, and the instrument removed and engaged onto a device to monitor its stiffness by using two strain gauges in four different directions. This monitoring method has the potential to be developed into a convenient, nondestructive turnkey system that allows in situ assessment of the integrity of NiTi instruments in the clinic. Upon fracture, which was indicated by a change in instrument stiffness, the fractured surface would be examined under a scanning electron microscope. Microscopic evaluation indicated a small area of fatigue fracture with a large area of final ductile fracture, whereby the latter was the major cyclic failure mode. Based on the results of this study, we concluded that a potential nondestructive integrity assessment method for NiTi rotary instruments was developed.
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http://dx.doi.org/10.4012/dmj.25.247 | DOI Listing |
PLoS One
January 2025
Aesthetic and Restorative Dentistry Department, College of Dentistry, University of Baghdad, Baghdad, Iraq.
This study evaluated the extent to which obturation materials bypass fractured endodontic instruments positioned in the middle and apical thirds of severely curved simulated root canals using different obturation techniques. Sixty resin blocks with simulated root canals were used, each with a 50° curvature, a 6.5 mm radius of curvature, and a length of 16.
View Article and Find Full Text PDFClin Oral Investig
January 2025
Department of Endodontics, Texas A&M College of Dentistry, Dallas, Texas, USA.
Objectives: The objective of this study is to evaluate the incidence and volume of contrast medium extrusion when activated with a laser and to compare these outcomes with those of other irrigation techniques.
Materials And Methods: Sixteen cadaver mandibles containing 116 single-rooted teeth were prepared using conventional rotary instrumentation. The teeth were randomly assigned to four irrigation groups: side-vented needle, sonic irrigation, laser activation at the orifice, and laser activation at the middle third of the canal.
Clin Case Rep
January 2025
Student Research Committee, School of Dentistry, Mashhad University of Medical Sciences Mashhad Iran.
Radix entomolaris (RE) characterized by an extra root in mandibular molars is a rare phenotype. When this condition coincides with complex root canal curvatures or S-shaped canals, root canal therapy (RCT) challenges arise. The present study presents three cases of RE along with complex root curvatures.
View Article and Find Full Text PDFAnal Bioanal Chem
January 2025
Bio-analytical Laboratory, Shantou University Medical College, No. 22, Xinling Road, Shantou, 515041, China.
A polarimeter is a common but critical instrument for measuring the optical rotation of chiral compounds, ranging from the pharmaceutical to chemical industry, or even employed in monitoring chemical reactions for research purposes. Developing a portable polarimeter helps to transfer the measurements from the laboratory to on-site detection. Herein, we design a new portable polarimeter with a "hand-held" scale.
View Article and Find Full Text PDFJ Oral Biol Craniofac Res
December 2024
Surgery Attachment, College of Dentistry, Qassim University, Qassim, Saudi Arabia.
Introduction: This is a double clinical trial conducted to study the patient satisfaction and comfort during and after surgical removal of impacted mandibular 3rd molar using Piezo electric tips.
Material And Methods: Two groups of 25 each [14 (56 %) males and 11 (44 %) females] and [18 (72 % males and 07 (28 %) females] represented the Rotary and Piezo groups respectively with bilateral impactions. one side of the patient is operated by piezo and the other side by rotary instrument after a gap of 2-3 week between the procedures.
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