Resistance to sliding of self-ligating brackets versus conventional stainless steel twin brackets with second-order angulation in the dry and wet (saliva) states

2001 ◽  
Vol 120 (4) ◽  
pp. 361-370 ◽  
Author(s):  
Glenys A. Thorstenson ◽  
Robert P. Kusy
Keyword(s):  
Stainless Steel ◽  
Second Order ◽  
Resistance To Sliding ◽  
Conventional Stainless Steel

scholarly journals A comparison of resistance to sliding of self-ligating brackets under an increasing applied moment

2011 ◽  
Vol 81 (5) ◽  
pp. 794-799 ◽  
Author(s):  
Benjamin T. Pliska ◽  
John P. Beyer ◽  
Brent E. Larson
Keyword(s):  
Stainless Steel ◽  
Analysis Of Variance ◽  
Continuous Measurement ◽  
Second Order ◽  
Nickel Titanium ◽  
Order Dimension ◽  
Canine Retraction ◽  
Resistance To Sliding ◽  
Post Test

Abstract Objective: To test the null hypotheses that at clinically relevant amounts of applied moment, there are no differences in the amount of resistance to sliding (RS) between self-ligating (SL) and conventionally ligated (CL) brackets on both stainless steel (SS) and nickel-titanium (NT) archwire. Materials and Methods: Three different SL brackets and one CL bracket, all 0.022″ slot, were tested on a custom-built device to simulate canine retraction mechanics in the second-order dimension. The setup allowed for simultaneous and continuous measurement of RS and applied moment at the bracket-archwire interface. The brackets tested were Damon3, In-Ovation R, Smartclip, and Victory, all of which were tested with 0.019″ × 0.025″ SS and NT archwires. The RS at calculated moments of 2000 g-mm and 4000 g-mm was determined and compared between the various brackets and both archwire types. Descriptive measures, analysis of variance, and Tukey-Kramer post-test comparisons were used to calculate results. Results: All brackets displayed a greater amount of RS with NT than with SS archwires. At the higher moment levels (4000 g-mm), no significant reduction in RS was found between CL and SL brackets on both SS and NT archwires. At lower levels of applied moment (2000 g-mm), reductions in RS of 18% (42.7 g) and 18% (38.5 g) were found between the CL bracket and the best performing SL bracket on NT and SS, respectively. Conclusion: At low values of applied moment, some statistical differences were found; however, in general, the differences in RS amongst the various SL and CL brackets tested may not be clinically relevant.

scholarly journals Effect of applied moment on resistance to sliding among esthetic self-ligating brackets

2013 ◽  
Vol 84 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Benjamin T. Pliska ◽  
Rick W. Fuchs ◽  
John P. Beyer ◽  
Brent E. Larson
Keyword(s):  
Stainless Steel ◽  
Analysis Of Variance ◽  
Second Order ◽  
The Other ◽  
Order Dimension ◽  
Testing Apparatus ◽  
Canine Retraction ◽  
Resistance To Sliding ◽  
Sliding Mechanics

ABSTRACT Objective: To determine the effect of mode of ligation and bracket material on resistance to sliding (RS) by comparing various esthetic brackets of conventionally ligated and self-ligating (SL) designs under an increasing applied moment in the second-order dimension. Materials and Methods: Eight different commercially available esthetic brackets of SL and conventional elastomeric-ligated (CL) designs were mounted on a testing apparatus to simulate canine retraction using sliding mechanics and the application of a moment on 0.019″×0.025″ stainless steel archwire. The samples examined were the CL brackets Clarity™, Inspire Ice™, SpiritMB™, and Mystique™, and the SL brackets ClaritySL™, In-OvationC™, In-OvationR™, and Smartclip™. The RS at calculated moments of 2000 g-mm and 4000 g-mm was determined and compared between the various brackets. Descriptive measures and one-way analysis of variance were used to calculate means and statistical differences among the bracket types. Results: The CL monocrystalline bracket displayed significantly greater (P < .05) RS than all other brackets tested. Among the other brackets, the range of RS values was 145.8–191.7 g and 291.9–389.2 g at moments of 2000 g-mm and 4000 g-mm, respectfully, though these differences were not significant (P < .05). All brackets tested displayed greater levels of RS (P < .05) at 4000 g-mm than at 2000 g-mm. Conclusion: With the exception of the CL monocrystalline bracket, all brackets displayed comparable amounts of RS regardless of mode of ligation or bracket slot material.

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

scholarly journals Effects of bracket design on critical contact angle

2013 ◽  
Vol 83 (5) ◽  
pp. 877-884 ◽  
Author(s):  
Xiaomo Liu ◽  
Peng Ding ◽  
Jiuxiang Lin
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Linear Regression ◽  
Resistance To Sliding ◽  
The Relationship ◽  
State Resistance ◽  
Critical Contact ◽  
Bracket Design

ABSTRACT Objective: To explore how the position of the bracket slots relative to the archwire influences the friction between them, and how bracket design affects the critical contact angle (θc). Materials and Methods: Two kinds of stainless steel archwires (0.016 and 0.019 × 0.025-inch) were tested against four kinds of brackets (Transmission Straight Archwire bracket, Domestic MBT bracket, Tip-Edge Plus bracket, and BioQuick self-ligation bracket) in the dry state. Resistance to sliding (RS) was measured as an increase in contact angle (θ). The value of θc was calculated by two linear regression lines. Results: Friction remained stable when θ < θc, then increased linearly when θ > θc. The θc values of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket were significantly larger than those for the Domestic MBT bracket and BioQuick self-ligation bracket. Conclusions: The relationship between the archwire and bracket slot significantly affects the resistance to sliding. The “edge-off” structure of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket could help to increase the θc value, and to expand the passive configuration range.

scholarly journals Pillow positioning facilitates independent bridging for bedpan use in pelvic fractures

1992 ◽  
Vol 48 (3) ◽  
pp. 41-44 ◽  
Author(s):  
Jeanette A. Fourie ◽  
Eileen M.P. Lief ◽  
Timothy T. Dunne
Keyword(s):  
Clinical Trial ◽  
Stainless Steel ◽  
Pelvic Fractures ◽  
Control Group ◽  
Mechanical Advantage ◽  
Block Randomisation ◽  
Significant Difference ◽  
Experimental Group ◽  
Conventional Stainless Steel

The idea of giving a patient with fractures of the pelvis a mechanical advantage, by placing pillows under his/her back in order to make bridging for the bedpan easier, was tested in this clinical trial. Twenty nine subjects were entered by block randomisation into the experimental group and twenty nine into the control group. The number of days from entry into the trial until independent bridging was noted. Independent bridging is defined as the patient being able to lift high enough to slide a conventional stainless steel bedpan under the buttocks. Results show that there is a significant difference in time to bridging (Y = 0,602, p = 0,0027) in favour of the experimental group. Other variables studied appear to marginally favour the control rather than the experimental group, thus suggesting that the pillow method could be used safely and effectively in the treatment of patients who have sustained a range of pelvic fractures.

scholarly journals Comparison of Galvanic Corrosion Potential of Metal Injection Molded Brackets to that of Conventional Metal Brackets with Nickel-Titanium and Copper Nickel-Titanium Archwire Combinations

2013 ◽  
Vol 14 (3) ◽  
pp. 488-495 ◽  
Author(s):  
S Chidambaram ◽  
M Vijay ◽  
D Praveen Kumar Varma ◽  
K Baburam Reddy ◽  
D Ravindranath ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Potential ◽  
Galvanic Corrosion ◽  
Nickel Titanium ◽  
Copper Nickel ◽  
Conventional Brackets ◽  
Titanium Wire ◽  
Conventional Bracket ◽  
Conventional Stainless Steel

ABSTRACT Aim The aim of the study is to investigate the galvanic corrosion potential of metal injection molding (MIM) brackets to that of conventional brackets under similar in vitro conditions with nickel-titanium and copper nickel-titanium archwires. Materials and methods Twenty-five maxillary premolar MIM stainless steel brackets and 25 conventional stainless steel brackets and archwires, 0.16 inch, each 10 mm length, 25 nickeltitanium wires, 25 copper nickel-titanium wires were used. They were divided into four groups which had five samples each. Combination of MIM bracket with copper nickel-titanium wire, MIM bracket with nickel-titanium wire and conventional stainless steel brackets with copper nickel-titanium wire and conventional stainless steel brackets with nickel-titanium wires which later were suspended in 350 ml of 1 M lactic acid solution media. Galvanic corrosion potential of four groups were analyzed under similar in vitro conditions. Precorrosion and postcorrosion elemental composition of MIM and conventional stainless steel bracket by scanning electron microscope (SEM) with energy dispersive spectroscope (EDS) was done. Results MIM bracket showed decreased corrosion susceptibility than conventional bracket with copper nickeltitanium wire. Both MIM and conventional bracket showed similar corrosion resistance potential in association with nickel-titanium archwires. It seems that both brackets are more compatible with copper nickel-titanium archwires regarding the decrease in the consequences of galvanic reaction. The EDS analysis showed that the MIM brackets with copper nickel-titanium wires released less metal ions than conventional bracket with copper nickeltitanium wires. Conclusion MIM brackets showed decreased corrosion susceptibility, copper nickel-titanium archwires are compatible with both the brackets than nickel-titanium archwires. Clinical significance Clinically MIM and conventional brackets behaved more or less similarly in terms of corrosion resistance. In order to decrease the corrosion potential of MIM brackets, more precise manufacturing technique should be improved to get a more smoother surface finish. How to cite this article Varma DPK, Chidambaram S, Reddy KB, Vijay M, Ravindranath D, Prasad MR. Comparison of Galvanic Corrosion Potential of Metal Injection Molded Brackets to that of Conventional Metal Brackets with Nickel-Titanium and Copper Nickel-Titanium Archwire Combinations. J Contemp Dent Pract 2013;14(3):488-495.

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