Cutting Efficiency and Preservation of Canal Curvature in Simulated Curved Canals Using Reciprocating and Non-Reciprocating Ni-Ti Systems

2015 ◽  
Vol 18 (2) ◽  
pp. 63-67
Author(s):  
Osama M. ◽  
Al-Gendi A. ◽  
Tawfik H.
Keyword(s):  
Cutting Efficiency

scholarly journals The Effects of Sterilization Procedures on the Cutting Efficiency of Endodontic Instruments: A Systematic Review and Network Meta-Analysis

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1559
Author(s):  
Mario Dioguardi ◽  
Enrica Laneve ◽  
Michele Di Cosola ◽  
Angela Pia Cazzolla ◽  
Diego Sovereto ◽  
...  
Keyword(s):  
Systematic Review ◽  
Selection Process ◽  
Meta Analysis ◽  
Indirect Comparison ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Cyclic Fatigue ◽  
P Value ◽  
Cutting Efficiency ◽  
Dental Instruments

Sterilization processes guarantee the sterility of dental instruments but can negatively affect instrument features by altering their physical and mechanical properties. The endodontic instrumentation can undergo a series of alterations, ranging from corrosion to variation in the cutting angle and then changes in the torsional properties and torsional fatigue resistance. This systematic literature review and meta-analysis aims to investigate alterations to the cutting efficiency of endodontic instruments that are induced by procedures for their disinfection and sterilization. Methodologies adopted for this investigation follow the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. The following were used as search terms on PubMed and Scopus: “endodontic sterilization”, “endodontic autoclave”, “cyclic fatigue”, “torsional”, “cutting efficiency”, “sterilization”, “surface characteristics”, and “corrosion”. At the end of the selection process, 36 articles were identified, and seven of them are included in this systematic review. The results of a meta-analysis conducted for the use of 10 autoclaving cycles shows a standardized mean difference (SMD) of 0.80 with a p-value equal to 0.04 with respect to effect on cutting efficiency. The network meta-analysis, through direct and indirect comparison between the different autoclave cycles (0, 1, 5, 10, and 15 cycles), revealed that treatment involving 15 autoclave cycles produced the most robust results in terms of having the greatest effects in terms of altered cutting efficiency with a probability of 57.7% and a SUCRA (surface under the cumulative ranking) of 80%. The alterations in the effects on cutting efficiency appear to be triggered after five cycles of sterilization by heat (autoclave). In conclusion, the meta-analysis of the data indicates that the autoclave sterilization protocol must not be repeated more than five times to preserve cutting efficiency. Within the limitations of this review, we can therefore establish that sterilization by autoclaving alone results in steel and NiTi instruments becoming less efficient in cutting after five cycles, as measured by a reduction in cutting efficiency.

scholarly journals A New System to Evaluate Comprehensive Performance of Hard-Rock Tunnel Boring Machine Cutterheads

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Ye Zhu ◽  
Wei Sun ◽  
Junzhou Huo ◽  
Zhichao Meng
Keyword(s):  
Stability Index ◽  
Tunnel Boring Machine ◽  
Efficiency Index ◽  
Structure Design ◽  
Cutting Efficiency ◽  
Evaluation Indexes ◽  
Average Value ◽  
Tunnel Boring ◽  
Rock Tunnel ◽  
Thrust And Torque

AbstractThe accurate performance evaluation of a cutterhead is essential to improving cutterhead structure design and predicting project cost. Through extensive research, this paper evaluates the performance of a tunnel boring machine (TBM) cutterhead for cutting ability and slagging ability. This paper propose cutting efficiency, stability, and continuity of slagging as the evaluation indexes of comprehensive cutterhead performance. On the basis of research of true TBM engineering applications, this paper proposes a calculation method for each index. A slagging efficiency index with a ratio of the maximum difference between the slagging amount and average slagging is established. And a slagging stability index with a ratio of the maximum slagging fluctuation and average slagging is presented. Meanwhile, a cutting efficiency index by the weighed average value of multistage rock fragmentation of a cutter’s specific energy is established. The Robbins and China Railway Construction Corporation (CRCC) cutterheads are evaluated. The results show that under the same thrust and torque, the slagging stability of the CRCC scheme is worse, but the slagging continuity of the CRCC scheme is better. The cutting ability index shows that the CRCC cutterhead is more efficient.

scholarly journals Effect of Pressure, Feed Rate, and Abrasive Mass Flow Rate on Water Jet Cutting Efficiency When Cutting Recombinant Bamboo

BioResources ◽  
2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Rongrong Li ◽  
Mats Ekevad ◽  
Xiaolei Guo ◽  
Jianwen Ding ◽  
Pingxiang Cao
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Feed Rate ◽  
Water Jet ◽  
Cutting Efficiency ◽  
Effect Of Pressure ◽  
Water Jet Cutting

Multisensor information-based adaptive control method for cutting head speed of roadheader

2020 ◽  
pp. 095440622095249
Author(s):  
Pengjiang Wang ◽  
Yang Shen ◽  
Rui Li ◽  
Kai Zong ◽  
Shichen Fu ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Fuzzy Logic Controllers ◽  
Control Effect ◽  
Cutting Efficiency ◽  
Cutting Head ◽  
Pi Controllers ◽  
Particle Swarm Optimisation Algorithm

An adaptive control method to improve the cutting head speed of roadheaders using multisensor information is proposed, so as to solve the problems of low cutting efficiency and low intelligence of roadheaders during underground tunnelling. The operation of a roadheader is analysed, and a control strategy for its cutting head speed is proposed. In addition, the cutting head speed is categorised into five gears according to the multisensor information of different cutting states. The controller for speed estimation is designed using a back propagation neural network optimised using an improved particle swarm optimisation algorithm. A control system is established in MATLAB to analyse the effectiveness of the method. The simulation results show that an IPSO-BP controller has the best control effect and can attain the target speed. The response time was lower than those of fuzzy logic controllers and traditional PI controllers by 46% and 68%, respectively, and the overshoot decreased by 4.69% and 12.19%, respectively. Furthermore, experimental research verified the effectiveness of this method. This method can adaptively adjust the cutting head speed of a roadheader using multisensor information and is important (both theoretical and practically) for extending the service life of roadheaders and improving tunnelling efficiency.

scholarly journals Single-file endodontic treatment -a perspective endodontic concept

2021 ◽  
pp. 78-78
Author(s):  
Slavoljub Zivkovic ◽  
Marijana Popovic-Bajic ◽  
Milica Jovanovic-Medojevic ◽  
Jelena Neskovic
Keyword(s):  
Smart Materials ◽  
Cyclic Fatigue ◽  
Correct Choice ◽  
Specific Design ◽  
Cutting Efficiency ◽  
Less Is More ◽  
Single File ◽  
Movement Dynamics ◽  
New Concepts ◽  
Full Rotation

The introduction of NiTi rotary files into endodontic practice is one of the biggest steps towards more successful and better canal treatment. New perspectives in endodontics have been opened, thanks primarily to the extreme flexibility and the feature of smart materials to be able to return to their original shape after deformation. New concepts of making these files in recent years include the introduction of new alloys to improve their features, ie a new specific design of the workpiece that provides efficient cutting and elimination of dentin with a significant reduction in stress and possible complications during hemomechanical processing of canals. The introduction of new alloys for the manufacture of files and their exposure to special thermal treatment has affected their superior features, greater flexibility and increased resistance to cyclic fatigue. The concept of single-file treatment includes various systems that use full rotation, reciprocal movements (or a combination thereof), or systems with eccentric and transaxial movements to increase cutting efficiency and reduce cyclic file fatigue. The new movements of the files also offer greater safety and efficiency because they significantly reduce the contact of the files with the walls and thus the stress during the preparation of the canal. The preparation of the canal with only one file is based on the concept of "less is more" and has fundamentally changed a lot in endodontics (conceptually, procedurally and economically), and made endodontic intervention simpler, faster and more certain. This significantly shortens the duration of endodontic intervention, eliminates the possibility of cross-contamination and significantly saves time and financial expenses for both patients and endodontists. Understanding the design of new NiTi files and the correct choice of movement dynamics during chemomechanical processing allows the practitioner to maximize his endodontic skill in each endodontic technique, to increase the efficiency of the intervention and significantly minimize the possibility of error. The aim of this paper is to present a perspective concept of single-file treatment, to present the development and strategies of different systems of single NiTi files and to present the indications and the possibility of their application in different clinical situations.

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