scholarly journals Differential scanning calorimetric investigations of three rotary nickel-titanium instrument systems before and after simulated clinical uses

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Khoa Van Pham
Keyword(s):  
Human Body ◽  
Clinical Performance ◽  
Clinical Situation ◽  
Nickel Titanium ◽  
Differential Scanning Calorimetric ◽  
Scanning Calorimetry ◽  
Transformation Temperatures ◽  
Significant Difference ◽  
Before And After ◽  
Niti Instruments

Abstract Background The transformation temperatures were important values, influencing the mechanical properties and clinical performance of nickel-titanium instruments. The aim of this study was to determine the transformation temperatures of three rotary nickel-titanium (NiTi) instruments: Reciproc, HyFlex CM Pro, and Neoniti before and after simulated clinical uses. Methods Ninety new NiTi instruments of three single-file instruments: Reciproc, HyFlex CM Pro, and Neoniti were divided into three groups. Thirty instruments of each group were divided into 3 subgroups (10 instruments for each subgroup): new, one-time simulated clinical used and sterilised, and three times simulated clinical used and sterilized subgroups. The instruments were in the as-received condition for the new subgroups, one time used in the plastic endo-training blocks and sterilised for the one-time subgroups, and three times used in the plastic endo-training blocks and sterilised for the three times subgroups. Each instrument in subgroups was cut into four small segments of 4–5 mm. All segments of instruments were analysed using Differential Scanning Calorimetry (DSC). Data was collected and analysed using SPSS version 20.0 with ANOVA test or Kruskal–Wallis test at the significant level of 0.05. Results There was not significant difference between before and after simulated clinical use with sterilised procedure in three NiTi instrument systems. The austenite-finish (Af) temperatures of three instrument systems were higher than that of the human body (37 °C), of these, the Af temperature of Neoniti was highest and that of HyFlex CM Pro was lowest. Conclusions The austenite-finish (Af) temperatures of three NiTi instruments were higher than that of human body temperature, therefore, material was in the phase transformation from martensite to austenite, gives the instruments more flexibility when used in the clinical situation.

scholarly journals Torsional Resistance of Heat-Treated Nickel-Titanium Instruments under Different Temperature Conditions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5295
Author(s):  
Hyo Jin Jo ◽  
Sang Won Kwak ◽  
Hyeon-Cheol Kim ◽  
Sung Kyo Kim ◽  
Jung-Hong Ha
Keyword(s):  
Nickel Titanium ◽  
Phase Transformation Temperature ◽  
Scanning Calorimetry ◽  
Temperature Conditions ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Rotary Instruments ◽  
Single Use ◽  
Niti Instruments ◽  
Niti Rotary Instruments

This study compared the torsional resistance of heat-treated nickel-titanium (NiTi) instruments under different temperature conditions. Four thermomechanically treated single-use NiTi rotary instruments were selected for this study: OneShape (OS), OneCurve (OC), WaveOne Gold (WOG) and HyFlex EDM (HFE). Each instrument was further subdivided by temperature into 2 subgroups. Maximum torque and the distortion angle until fracture occurred were evaluated. Differential scanning calorimetry analysis was performed to measure the phase transformation temperature. Statistical analysis was performed using a two-way ANOVA and t-test (p < 0.05). Fractured fragments were observed using scanning electron microscopy (SEM). The two-way ANOVA showed no significant differences for different temperature conditions. At both room (RT) and body temperature (BT), OS was predominantly austenite while HFE was martensite. OC and WOG were predominantly martensite at RT and mixed phase at BT. At BT, more than half of WOG was martensite, while half of OC was austenite. SEM examination showed no topographical differences between instruments in different temperature groups. In relation to a limitation of this study, there was no difference in torsional resistance of NiTi rotary instruments between the BT and RT conditions. This implies that clinicians do not need to consider a decrease of torsional resistance of heat-treated NiTi instruments at BT.

scholarly journals Do NiTi Instruments show Defects before Separation? Defects caused by Torsional Fatigue in Hand and Rotary Nickel-Titanium (NiTi) Instruments which Lead to Failure during Clinical Use

2012 ◽  
Vol 13 (6) ◽  
pp. 867-872 ◽  
Author(s):  
Sudhir Kumar ◽  
P Ratnakar ◽  
NV Murali Krishna Chakka ◽  
Sanjib Das ◽  
Anandamy Bagchi ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
Clinical Use ◽  
New Classification ◽  
Torsional Fatigue ◽  
Anterior Teeth ◽  
Microscopic Evaluation ◽  
Different Types ◽  
Before And After ◽  
The Difference ◽  
Niti Instruments

ABSTRACT Aims Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments. Materials and methods Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files. After every use, the files were observed visually and microscopically (Stereomicroscope at 10×) to evaluate the defects caused by torsional fatigue. Scoring was given according to a new classification formulated which gives an indication of the severity of the defect or damage. Statistical analysis Data was statistically analyzed using KruskallWallis and Mann-Whitney U test. Results Number of files showing defects were more under stereomicroscope than visual examination. But, the difference in the evaluation methods was not statistically significant. The different types of defects observed were bent instrument, straightening/stretching of twist contour and partial reverse twisting. Endowave files showed maximum number of defects followed by ProTaper for hand use and least in ProTaper Rotary. Conclusion Visible defects due to torsional fatigue do occur in NiTi instruments after clinical use. Both visual and microscopic examinations were efficient in detecting defects caused due to torsional fatigue. This study emphasizes that all files should be observed for any visible defects before and after every instrumentation cycle to minimize the risk of instrument separation and failure of endodontic therapy. How to cite this article Chakka NVMK, Ratnakar P, Das S, Bagchi A, Kumar S, Anumula L. Do NiTi Instruments show Defects before Separation? Defects caused by Torsional Fatigue in Hand and Rotary Nickel-Titanium (NiTi) Instruments which Lead to Failure during Clinical Use. J Contemp Dent Pract 2012;13(6):867-872.

scholarly journals Geometric Analysis of Maxillary First Premolar Prepared by Two Nickel-Titanium Rotary Instruments

2014 ◽  
Vol 15 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Dina Al-Sudani ◽  
Majed Almalki ◽  
Saad Al-Shahrani ◽  
Michael Ahlquist
Keyword(s):  
Cross Sections ◽  
Root Canal ◽  
Geometric Analysis ◽  
Microcomputed Tomography ◽  
Nickel Titanium ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Before And After ◽  
Canal Transportation ◽  
Shaping Ability

ABSTRACT Aim The present study was conducted with the aim of evaluating and comparing the shaping ability of two Nickel-titanium rotary instruments, with two disparate design features, on root canal geometry of extracted human maxillary first premolars using microcomputed tomography. Study design Twenty four bifurcated maxillary first premolars were divided into two groups and embedded in a rubber-based impression material. Both groups were submitted to microcomputed tomography before and after canal preparation (buccal and palatal) with either ProFile Vortex or Revo-S rotary instruments. Images were reconstructed and cross-sections corresponding to a distance 1, 2, 3, 4, 5, 6, and 7 mm from the anatomical apex were selected for canal transportation analysis. Volume changes were also measured. Results The degree and direction of canal transportation were non-significant for both instruments. Statistically significant differences were observed only between levels in the buccal canal in both groups. There was no significant difference between the two rotary systems in regards to the volume of dentin removed. Conclusion Our findings showed that ProFile Vortex and Revo-S instruments respected the original root canal anatomy and behaved similarly. ProFile Vortex rotary systems produced with innovative process were concluded to shape the upper maxillary premolar by leading minimal canal transportation, similar to Revo-S, rotary systems produced from traditional process. How to cite this article Al-Sudani D, Almalki M, Al-Shahrani S, Ahlquist M. Geometric Analysis of Maxillary First Premolar Prepared by Two Nickel-Titanium Rotary Instruments. J Contemp Dent Pract 2014;15(2):174-180.

Dissolution/reprecipitation technique for waste polyolefin recycling using new pure and blend organic solvents

2013 ◽  
Vol 33 (5) ◽  
pp. 471-481 ◽  
Author(s):  
Arkan J. Hadi ◽  
Ghazi Faisal Najmuldeen ◽  
Kamal Bin Yusoh
Keyword(s):  
High Density Polyethylene ◽  
Raw Materials ◽  
Scanning Calorimetry ◽  
Polymer Recycling ◽  
Plastic Materials ◽  
Pure Solvent ◽  
Significant Difference ◽  
Before And After ◽  
Reprecipitation Method ◽  
Waste Polymer

Abstract Restoration of waste polymer based on low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) is studied using the dissolution/reprecipitation method. In this technique, pure turpentine, turpentine/petroleum ether (PetE) and turpentine/benzene as solvents with different fractions and PetE and n-hexane as non-solvents were examined. Commercial polymer products (packaging food, bags, laboratory plastic materials, detergent containers) used as raw materials were optimized with model polymers. Polymer recoveries in every case were <94%. Fourier transform infrared (FTIR) spectra and tensile mechanical properties of the samples before and after recycling were measured. Potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity), before and after recycling, using differential scanning calorimetry (DSC). The blend solvents were seen as good solvents for all polyolefins used and the dissolution temperature was less than the pure solvent at the same time. High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

Potential solvent for reconditioning polyolefin waste materials

2012 ◽  
Vol 32 (8-9) ◽  
pp. 585-591 ◽  
Author(s):  
Arkan J. Hadi ◽  
Ghazi Faisal Najmuldeen ◽  
Iqbal Ahmed
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
High Density Polyethylene ◽  
Waste Materials ◽  
Scanning Calorimetry ◽  
Polymer Recycling ◽  
Significant Difference ◽  
Before And After ◽  
Waste Polymer

Abstract Waste polymer reconditioning was examined by a method of dissolution/reprecipitation on low- and high-density polyethylene (PE) and polypropylene (PP). Toluene and petroleum ether, in different proportions, were used as solvents, and n-hexane was used as a non-solvent. Commercial polymer products used on an everyday basis were used with a virgin polymer, to optimize the qualities of the final product, and 98% polymer was recovered in each case. Fourier transform infrared spectroscopy (FTIR) images and tensile mechanical properties of the samples, before and after recycling, were analyzed. The potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity) before and after recycling, using differential scanning calorimetry (DSC). High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

scholarly journals Impact of Endodontic Instrumentation on Surface Roughness of Various Nickel-Titanium Rotary Files

2020 ◽  
Author(s):  
Muhammad Sohail Zafar
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Nickel Titanium ◽  
Root Mean Square Roughness ◽  
Contact Mode ◽  
Root Canals ◽  
Working Length ◽  
Mandibular Molar ◽  
Significant Difference ◽  
Before And After

Abstract Objectives The aim of the present study was to evaluate the surface roughness (SR) of various nickel-titanium (NiTi) rotary endodontic instruments (ProTaper Next [PTN], WaveOne Gold [WOG], and ProTaper Gold [PTG]) before and after root canal instrumentation. Materials and Methods For each type (PTN, WOG, and PTG), the endodontic instrumentation was performed using extracted mandibular molar teeth’s curved mesial root canals (curvature: 20–40 degrees) after determining the working length. Each NiTi file was cleaned, and sterilized following preparation of four root canals and characterized for surface properties before and after endodontic instrumentation using a contact-mode three-dimensional surface profiler. The data were analyzed statistically using Statistical Package for the Social Sciences for SR parameters including average surface roughness value (Sa), root mean square roughness (Sq), and peak to valley height (Sz). Results Preinstrumentation assessment revealed a significant difference for all the three SR variables (p < 0.05) for the cutting blade and the flute area. WOG instruments showed the highest SR values (p = 0.000). The postinstrumentation assessment revealed significant differences in SR values in the blade and the flute between the three groups (p < 0.05), with WOG and PTG exhibiting the highest values in the blade and flute sections, respectively. Conclusions The SR parameters of intact PTN, WOG, and PTG NiTi files vary and that was increased following the endodontic instrumentation.

scholarly journals Shaping ability of two heat treated rotary NiTi instruments using different kinematics/in vitro study

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Engy M. Kataia ◽  
Mohamed Mokhtar Nagy ◽  
Mohamed M. Kataia ◽  
Hala Fayek Khalil
Keyword(s):  
In Vitro Study ◽  
Preparation Time ◽  
Heat Treated ◽  
Significant Difference ◽  
Before And After ◽  
Canal Transportation ◽  
Niti Instruments ◽  
Post Hoc ◽  
Shaping Ability

Abstract Background Comparing shaping ability of Azure and Fanta AF One in rotation and reciprocation. This study was conducted on 40 resin blocks, having canal curvatures 30°-angle and of 16-mm length. The blocks were assigned to 4-groups according to the instrument and motion used: Azure/Rotation (A/Rt), Fanta AF one/Rotation (F/Rt), Azure/Reciprocation (A/Rec) and Fanta AF one/Reciprocation (F/Rec). For both systems single file 25, taper 0.06 were used. Digital images were taken before and after instrumentation. Adobe Photoshop was used to overlap post and pre-instrumentation images to assess canal transportation at 1, 4, 7-mm; representing apical, middle and cervical levels respectively. Stopwatch was used to document the time taken for canal preparation. One-way ANOVA followed by Tukey post hoc test, used to compare between more than two groups in non-related samples. Results At the apical level, no statistically significant difference was found between both files in either rotation or reciprocation. However, reciprocation motion showed significantly lower transportation levels in both files. No significant difference was found among groups at the middle and cervical levels. Regarding preparation time, Reciprocation in both groups was significantly longer. Conclusions The use of reciprocation motion showed minimized apical canal transportation in both files however in longer preparation time.

scholarly journals Evolution of Nickel–titanium Alloys in Endodontics

2017 ◽  
Vol 18 (11) ◽  
pp. 1090-1096 ◽  
Author(s):  
Sukumaran Anil ◽  
Prasanna Neelakantan ◽  
Wadih Nassif
Keyword(s):  
Titanium Alloys ◽  
Clinical Performance ◽  
Surface Hardness ◽  
Cyclic Fatigue ◽  
Surface Treatments ◽  
Nickel Titanium ◽  
Fatigue Properties ◽  
Rotary Instruments ◽  
Nickel Titanium Alloys ◽  
Niti Instruments

ABSTRACT To improve clinical use of nickel–titanium (NiTi) endodontic rotary instruments by better understanding the alloys that compose them. A large number of engine-driven NiTi shaping instruments already exists on the market and newer generations are being introduced regularly. While emphasis is being put on design and technique, manufacturers are more discreet about alloy characteristics that dictate instrument behavior. Along with design and technique, alloy characteristics of endodontic instruments is one of the main variables affecting clinical performance. Modification in NiTi alloys is numerous and may yield improvements, but also drawbacks. Martensitic instruments seem to display better cyclic fatigue properties at the expense of surface hardness, prompting the need for surface treatments. On the contrary, such surface treatments may improve cutting efficiency but are detrimental to the gain in cyclic fatigue resistance. Although the design of the instrument is vital, it should in no way cloud the importance of the properties of the alloy and how they influence the clinical behavior of NiTi instruments. Clinical significance Dentists are mostly clinicians rather than engineers. With the advances in instrumentation design and alloys, they have an obligation to deal more intimately with engineering consideration to not only take advantage of their possibilities but also acknowledge their limitations. How to cite this article Ounsi HF, Nassif W, Grandini S, Salameh Z, Neelakantan P, Anil S. Evolution of Nickel–titanium Alloys in Endodontics. J Contemp Dent Pract 2017;18(11):1090-1096.

scholarly journals The influence of heat treatment on microstructure and phase transformation Temperatures of Cu-Al-Ni shape memory alloy

2019 ◽  
Vol 68 (3-4) ◽  
pp. 111-118 ◽  
Author(s):  
Ivana Ivanić ◽  
Mirko Gojić ◽  
Borut Kosec ◽  
Tamara Holjevac Grgurić ◽  
Stjepan Kožuh
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Microstructural Analysis ◽  
Solution Annealing ◽  
Scanning Calorimetry ◽  
Transformation Temperatures ◽  
Casting Technique ◽  
Before And After

This paper presents the results of thermal and microstructural analysis of Cu-Al-Ni shape memory alloy before and after heat treatment. After casting, a bar of Cu-12.8 Al-4.1 Ni (wt.%) alloy, obtained by the vertical continuous casting technique, was subjected to a certain heat treatment procedure. Solution annealing was performed at 850 °C for 60 min, followed by water quenching. Tempering was then performed at four different temperatures (150 °C, 200 °C, 250 °C and 300 °C). The microstructural results were obtained by optical and scanning electron microscopy. Thermodynamic calculation of ternary Cu-Al-Ni system under equilibrium was performed using Thermo-Calc 5 software. Phase transformation temperatures were determined by differential scanning calorimetry (DSC). The DSC results show the highest values of transformation temperatures in as-cast state. After solution annealing and tempering, the transformation temperatures show lower values with exceptional stability of Ms temperature (martensite start temperature).

scholarly journals Comparison of Surface Characteristics of Apical Third of Rotary NiTi Files Manufactured from Different Phases of NiTi before and after Use: an Sem Analysis

2016 ◽  
Vol 04 (01) ◽  
pp. 018-022
Author(s):  
Dhwani Bakhai ◽  
Vibha Hegde
Keyword(s):  
Surface Defects ◽  
File Systems ◽  
Surface Characteristics ◽  
Sem Analysis ◽  
P Value ◽  
Austenitic Phase ◽  
Significant Difference ◽  
Before And After ◽  
Multiple Uses ◽  
Niti Instruments

AbstractClinically, there is a real potential for rotary NiTi instruments to separate in the canal; hence increasing the resistance to fracture has been a focus in the designing of new NiTi rotary systems. NiTi alloys go through various transitional phases and these have been utilized by manufacturers in different file systems. Aim: To evaluate and compare the surface changes of rotary nickel-titanium instruments manufactured from the Austenite phase, M-wire technology and R- phase before and after multiple uses. Materials and Methodology: 60 freshly extracted human mandibular premolars with a single, straight canal were selected. They were divided into 3 groups of 20 teeth each. Cleaning and Shaping was carried out using the crown down technique. All instruments were evaluated for defects under Scanning Electron Microscope (SEM) before and after multiple uses and scored for the defects. Results were statistically analyzed using Kruskal Wallis and Mann Whitney U test. Results: The p-value was <0.0001, indicating a statistically significant difference between the three groups in terms of resistance to surface defects. Conclusion: R-phase technology had superior resistance to surface defects, followed by M-wire and the austenitic phase.

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