scholarly journals Lumbar Scoliosis Induction in Juvenile Dogs by Three-dimensional Modulation of Spinal Growth Using Nickel-Titanium Coil Springs

2017 ◽  
Vol 130 (21) ◽  
pp. 2579-2584 ◽  
Author(s):  
Heng-Yan Zhang ◽  
Qi-Yi Li ◽  
Zhi-Hong Wu ◽  
Yu Zhao ◽  
Gui-Xing Qiu
Keyword(s):  
Three Dimensional ◽  
Nickel Titanium ◽  
Spinal Growth ◽  
Lumbar Scoliosis

scholarly journals Finite element analysis comparing WaveOne Gold and ProTaper Next endodontic file segments subjected to bending and torsional load

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Amira Galal Ismail ◽  
Mohamed Hussein Abdelfattah Zaazou ◽  
Manar Galal ◽  
Nada Omar Mostafa Kamel ◽  
Mohamed Abdulla Nassar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Clinical Situation ◽  
Nickel Titanium ◽  
Behavioral Differences ◽  
Element Analysis ◽  
Torsional Resistance ◽  
Computer Tomography Scanning ◽  
Cantilever Bending

Abstract Background The objective of this study was to assess the bending and torsional properties of two nickel-titanium endodontic files with equivalent sizes and various designs and alloys using finite element analysis, ProTaper Next®X2 (PTN) size 25 with 0.06 taper and WaveOne Gold® (WOG) primary size 25 with 0.07 taper. Methodology Two-dimensional models of the two files PTN and WOG were created using computer tomography scanning and stereomicroscope to produce a three-dimensional digital model. Instrument behavior under bending or torsional conditions was numerically analyzed in SolidWorks software package. Result ProTaper Next® revealed higher flexibility than WaveOne Gold® when exposed to cantilever bending but showed higher stress accumulation than WOG. In terms of torsional resistance, PTN also revealed higher torsional resistance than WOG. Conclusion The geometry of the instrument, thermomechanical treatment of the alloy, and its composition affect the mechanical behavior (bending and torsion) of nickel titanium rotary files. Hence, being aware of these behavioral differences, each clinician will be able to use the adequate file according to the clinical situation in addition to the manufacturer’s instructions.

scholarly journals A new elastic slot system and V-wire mechanics

2017 ◽  
Vol 87 (5) ◽  
pp. 774-781 ◽  
Author(s):  
Andrea Wichelhaus
Keyword(s):  
Permanent Deformation ◽  
Biomechanical Testing ◽  
Three Dimensional ◽  
Nickel Titanium ◽  
Dental Arch ◽  
Rectangular Slot ◽  
Torque Measurements ◽  
Conventional Brackets ◽  
The Wire ◽  
The Moment

ABSTRACT Objective: To biomechanically test a new elastic slot system and V-wire mechanics. Materials and Methods: Conventional twin and self-ligating brackets and the new elastodynamic bracket were biomechanically tested. The conventional brackets had a rectangular 0.022′′ slot and the new elastodynamic bracket had a V-slot, a new slot geometry. Torque measurements were performed with 0.018′′ × 0.025′′ and 0.019′′ × 0.025′′ stainless steel (ss) archwires. A nickel-titanium V wire was used for the biomechanical measurements on the elastodynamic bracket. The measurements were done with the aid of a six-component measuring sensor. Results: The results of the biomechanical testing revealed play in the brackets with rectangular slot geometry. The V slot in the elastodynamic bracket assured that the wire fit perfectly in the slot. Dynamic moments of 5 to 10 Nmm were transmitted without any play. No permanent deformation of the slot occurred in the new elastodynamic bracket because of the elastic slot. Conclusion: Control of torque for three-dimensional positioning of the teeth in the dental arch with rectangular slot geometry as used in straight-wire therapy is difficult. If torque is bent into the wire, because of the play there is a high risk that either too much, too little, or no moment is transmitted to the teeth. The V-slot archwire/bracket geometry in conjunction with nickel titanium composition has no play and allows a reduction of forces and moments with direct and continuous transmission of torque in the bracket. Because of the elasticity of the bracket, there is an upper limit to the moment possible.

scholarly journals Force Magnitude and Duration Effects on Amount of Tooth Movement and Root Resorption in the Rat Molar

2008 ◽  
Vol 78 (3) ◽  
pp. 502-509 ◽  
Author(s):  
Carmen Gonzales ◽  
Hitoshi Hotokezaka ◽  
Masako Yoshimatsu ◽  
Joseph H. Yozgatian ◽  
M. Ali Darendeliler ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Tooth Movement ◽  
Root Resorption ◽  
Three Dimensional ◽  
Nickel Titanium ◽  
Second Molar ◽  
Force Application ◽  
Surface Areas ◽  
Force Magnitude ◽  
Group A

Abstract Objective: To test the hypothesis that there is no difference in the effect of different continuous moderate to very heavy forces on root resorption or amount of tooth movement. Materials and Methods: In the study, 10, 25, 50 and 100 g mesial force were applied to the maxillary first molars of rat using nickel titanium closed-coil springs for 3 days, 14 days, and 28 days. The molars were extracted and the surface areas of the root resorption craters were measured using scanning electron microscope. The depths of the root resorption craters were measured using a three-dimensional laser scanning microscope. Tooth movement of the maxillary first molar was measured in relation to the maxillary second molar on digitized lateral cephalometric radiographs. Results: Three days after force application, the tooth movement was not proportionally related to force magnitude. However, 14 days of force application resulted in significantly more tooth movement in the 10, 25, and 50 g force groups than in the 100 g force group. A force application of 10 g produced significantly more tooth movement at 28 days than all the other three force applications. The largest and deepest resorption craters were observed in the disto-buccal root followed by disto-palatal, middle-buccal, middle-palatal, and mesial root. Root resorption and tooth movement increased over time from 3 to 28 days. As heavier forces were applied, greater root resorption occurred. Conclusion: The hypothesis is rejected. The light mesially oriented forces, as applied in this study, produced more tooth movement and less root resorption compared with heavier forces.

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.

New growth rod concept provides three dimensional correction, spinal growth, and preserved pulmonary function in early-onset scoliosis

2020 ◽  
Vol 44 (9) ◽  
pp. 1773-1783
Author(s):  
Simon Toftgaard Skov ◽  
Haisheng Li ◽  
Ebbe Stender Hansen ◽  
Kristian Høy ◽  
Peter Helmig ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Early Onset ◽  
Three Dimensional ◽  
Early Onset Scoliosis ◽  
Spinal Growth

Selective laser melting of high aspect ratio 3D nickel – titanium structures for MEMS applications

2005 ◽  
Vol 890 ◽  
Author(s):  
Paul Chalker ◽  
Adam Clare ◽  
Sean Davies ◽  
Christopher J. Sutcliffe ◽  
Sozon Tsopanos
Keyword(s):  
Aspect Ratio ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
High Aspect Ratio ◽  
Three Dimensional ◽  
Nickel Titanium ◽  
Niti Shape Memory Alloy ◽  
Laser Melting ◽  
Microelectromechanical Devices ◽  
First Time

ABSTRACTSelective laser melting has been used to build high aspect ratio, three-dimensional NiTi components for the first time. The influence of laser dwell time and raster pitch on the density of NiTi shape memory alloy parts and their resolvable feature sizes are reported. The properties of shape memory springs produced by this method are reported and the application of selective laser melted NiTi components in microelectromechanical devices is discussed.

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