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The Angle Orthodontist Nov 2014To analyze the effect of various coating formulations on the mechanical and corrosion properties of nickel-titanium (NiTi) orthodontic wires.
OBJECTIVE
To analyze the effect of various coating formulations on the mechanical and corrosion properties of nickel-titanium (NiTi) orthodontic wires.
MATERIALS AND METHODS
Uncoated, rhodium-coated, and nitrified NiTi wires were observed with a three-point-bend test, surface roughness (Ra) measurement, scanning electron microscopy, energy dispersive spectroscopy, and electrochemical testing (open circuit potential, electrochemical impedance spectroscopy, and cyclic polarization scan). Differences in the properties of tested wire types were analyzed with analysis of variance and Tukey post hoc test.
RESULTS
Uncoated and nitrified NiTi wires showed similar mechanical and anticorrosive properties, while rhodium-coated NiTi wires showed the highest Ra and significantly higher modulus of elasticity, yield strength, and delivery of forces during loading but not in unloading. Rhodium-coated NiTi wires also had the highest corrosion current density and corrosion potential, lowest impedance modulus, and two time constants on Bode plot, one related to the Rh/Au coating and the other to underlying NiTi.
CONCLUSION
Working properties of NiTi wires were unaffected by various coatings in unloading. Nitrification improved corrosion resistance. Rhodium coating reduced corrosion resistance and pronounced susceptibility to pitting corrosion in artificial saliva because of galvanic coupling between the noble coating and the base alloy.
Topics: Coated Materials, Biocompatible; Corrosion; Dental Alloys; Dielectric Spectroscopy; Elastic Modulus; Electrolysis; Gold; Humans; Materials Testing; Microscopy, Electron, Scanning; Nickel; Orthodontic Wires; Pliability; Polarography; Rhodium; Saliva, Artificial; Spectrometry, X-Ray Emission; Stress, Mechanical; Surface Properties; Titanium
PubMed: 24654939
DOI: 10.2319/090413-651.1 -
The Angle Orthodontist Mar 2015To test the hypothesis that treatment time, debris/biofilm, and oral pH have an influence on the physical-chemical properties of orthodontic brackets and arch wires.
OBJECTIVE
To test the hypothesis that treatment time, debris/biofilm, and oral pH have an influence on the physical-chemical properties of orthodontic brackets and arch wires.
MATERIALS AND METHODS
One hundred twenty metal brackets were evaluated. They were divided into four groups (n = 30) according to treatment time: group C (control) and groups T12, T24, and T36 (brackets recovered after 12, 24, and 36 months of treatment, respectively). Rectangular stainless-steel arch wires that remained in the oral cavity for 12 to 24 months were also analyzed. Dimensional stability, surface morphology, composition of brackets, resistance to sliding of the bracket-wire set, surface roughness of wires, and oral pH were analyzed. One-way analysis of variance, followed by a Tukey multiple comparisons test, was used for statistical analysis (P < .05).
RESULTS
Carbon and oxygen were shown to be elements that increased expressively and in direct proportion to time, and there was a progressive increase in the coefficient of friction and roughness of wires as a function of time of clinical use after 36 months. Oral pH showed a significant difference between group T36 and its control (P = .014).
CONCLUSIONS
The hypothesis was partially accepted: treatment time and biofilm and debris accumulation in bracket slots were shown to have more influence on the degradation process and frictional force of these devices than did oral pH.
Topics: Adolescent; Adult; Biofilms; Carbon; Chemical Phenomena; Dental Alloys; Dental Deposits; Electron Probe Microanalysis; Friction; Humans; Hydrogen-Ion Concentration; Materials Testing; Microscopy, Electron, Scanning; Orthodontic Brackets; Orthodontic Wires; Oxygen; Saliva; Stainless Steel; Surface Properties; Time Factors; Young Adult
PubMed: 25023707
DOI: 10.2319/032914-234.1 -
The Angle Orthodontist Jan 2015To test for differences in loading and unloading forces delivered by six coated nickel-titanium wires and their noncoated equivalents. (Comparative Study)
Comparative Study
OBJECTIVE
To test for differences in loading and unloading forces delivered by six coated nickel-titanium wires and their noncoated equivalents.
MATERIALS AND METHODS
From six commercial companies, 0.016-inch diameter round and 0.016 × 0.022-inch rectangular cross-section nickel-titanium wires were procured "as is": Rocky Mountain Orthodontics (Denver, Colo), TP Orthodontics (La Porte, Ind), American Orthodontics (AO; Sheboygan, Wis), G&H (Franklin, Ind), Opal Orthodontics (South Jordan, Utah), and Forestadent USA (St Louis, Mo) (round only). The wires were evaluated using a three-point bending test based on the method in ISO Standard 15841.
RESULTS
No statistically significant differences (P > .05) in force values were found between coated and noncoated wires, listed by deflection in three-point bending, for these specific groups: 1 mm, TP round; 2 mm, TP round and G&H rectangular; 3 mm, G&H round and G&H rectangular; 2.5 mm,TP round and G&H rectangular; 1.5 mm, TP round, G&H round, G&H rectangular, and AO rectangular; and 0.5 mm, AO rectangular and G&H round.
CONCLUSION
Some manufacturers market esthetic wires delivering forces similar to the equivalent noncoated wires, when tested according to a standard three-point bend method.
Topics: Coated Materials, Biocompatible; Dental Alloys; Dental Stress Analysis; Esthetics, Dental; Humans; Materials Testing; Nickel; Orthodontic Wires; Pliability; Stress, Mechanical; Surface Properties; Titanium
PubMed: 24901067
DOI: 10.2319/092513-701.1 -
The Angle Orthodontist Sep 2021To examine the torque moment that occurs between esthetic brackets and bendable alloy (stainless steel [SS], titanium-molybdenum [Ti-Mo], and titanium-niobium [Ti-Nb])...
OBJECTIVES
To examine the torque moment that occurs between esthetic brackets and bendable alloy (stainless steel [SS], titanium-molybdenum [Ti-Mo], and titanium-niobium [Ti-Nb]) wires.
MATERIALS AND METHODS
This study examined ceramic (CR), zirconium oxide (ZC), polycarbonate (PC), and conventional metallic brackets (MT) (upper, 0.018-inch and 0.022-inch slots) combined with SS, Ti-Mo, and Ti-Nb wires using elastic module ligation. The torque moments delivered by various wire and bracket combinations were measured using a torque gauge apparatus. The wire torque angles at 5-40° were examined.
RESULTS
The torque value increased in the order of CR, ZC, MT, and PC brackets for both 0.018-inch and 0.022-inch slots. The fracture points of the CR and ZC brackets combined with SS and Ti-Mo wires were approximately more than 30° and 35°, respectively. No fracture points were detected in the combination of ZC brackets and Ti-Nb wires.
CONCLUSIONS
The current study identified the material characteristics of CR, ZR, and PC brackets during torque tooth movements. The present results demonstrate a characteristic combined effect between different esthetic brackets and bendable alloy wires.
Topics: Alloys; Dental Stress Analysis; Esthetics, Dental; Materials Testing; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Stainless Steel; Titanium; Torque
PubMed: 33822872
DOI: 10.2319/081820-729.1 -
The Angle Orthodontist Sep 2016To evaluate and compare the effects of nanostructured, diamondlike, carbon (DLC) coating and nitrocarburizing on the frictional properties and biocompatibility of...
OBJECTIVE
To evaluate and compare the effects of nanostructured, diamondlike, carbon (DLC) coating and nitrocarburizing on the frictional properties and biocompatibility of orthodontic stainless steel archwires.
MATERIALS AND METHODS
Plasma-enhanced chemical vapor deposition technology was applied to coat DLC films onto the surface of austenitic stainless steel wires, and salt-bath nitrocarburizing technology was employed to achieve surface hardening of other wires. Surface and cross-sectional characteristics, microhardness, modulus of elasticity, friction resistance, corrosion resistance, and cell toxicity of the modified and control wires were analyzed.
RESULTS
The surfaces of the DLC-coated and nitrocarburized wires were both smooth and even. Compared with the control, the DLC-coated wires were increased in surface hardness 1.46 times, decreased in elastic modulus, reduced in kinetic friction coefficient by 40.71%, and decreased in corrosion current density by two orders of magnitude. The nitrocarburized wire was increased in surface hardness 2.39 times, exhibited an unchanged elastic modulus, demonstrated a decrease in maximum static friction force of 22.2%, and rose in corrosion current density two orders of magnitude. Cytotoxicity tests revealed no significant toxicity associated with the modified wires.
CONCLUSIONS
DLC coating and nitrocarburizing significantly improved the surface hardness of the wires, reduced friction, and exhibited good biocompatibility. The nanostructured DLC coating provided excellent corrosion resistance and good elasticity, and while the nitrocarburizing technique substantially improved frictional properties, it reduced the corrosion resistance of the stainless steel wires to a lesser extent.
Topics: Carbon; Cross-Sectional Studies; Dental Alloys; Friction; Materials Testing; Orthodontic Brackets; Orthodontic Wires; Stainless Steel; Surface Properties; Titanium
PubMed: 26927019
DOI: 10.2319/090715-602.1 -
The Angle Orthodontist May 2007To test the antiadherent and antibacterial properties of surface modification of orthodontic wires with photocatalytic titanium oxide (TiO(2)).
OBJECTIVE
To test the antiadherent and antibacterial properties of surface modification of orthodontic wires with photocatalytic titanium oxide (TiO(2)).
MATERIALS AND METHODS
TiO(2) was coated on the surface of the orthodontic wires by a sol-gel thin film dip-coating method. Bacterial adhesion to the wires was evaluated by the weight change of the wires. The antibacterial activity of the surface-modified orthodontic wires was demonstrated by the dilution agar plate method for Streptococcus mutans and spectrophotometry for Porphyromonas gingivalis.
RESULTS
The orthodontic wires coated with the photocatalytic TiO(2) showed an antiadherent effect against S. mutans compared with the uncoated wires. The bacterial mass that bound to the TiO(2)-coated orthodontic wires remained unchanged, whereas that of the uncoated wires increased by 4.97%. Furthermore, the TiO(2)-coated orthodontic wires had a bactericidal effect on S. mutans and P. gingivalis, which cause dental caries and periodontitis, respectively. The antiadherent and antibacterial mechanisms of TiO(2) to break down the cell wall of those bacteria were revealed by scanning electron microscopy.
CONCLUSION
The surface modification of orthodontic wires with photocatalytic TiO(2) can be used to prevent the development of dental plaque during orthodontic treatment.
Topics: Anti-Bacterial Agents; Bacterial Adhesion; Coated Materials, Biocompatible; Orthodontic Wires; Porphyromonas gingivalis; Streptococcus mutans; Surface Properties; Titanium
PubMed: 17465657
DOI: 10.2319/0003-3219(2007)077[0483:SMOOWW]2.0.CO;2 -
International Journal of Environmental... Feb 2023Metal ion release studies were carried out on three of the most commonly used orthodontic wires in the clinic: austenitic stainless steel, Ti-Mo, and superelastic NiTi,...
Metal ion release studies were carried out on three of the most commonly used orthodontic wires in the clinic: austenitic stainless steel, Ti-Mo, and superelastic NiTi, using three mouthwashes with different fluoride concentrations: 130, 200, and 380 ppm. Immersions were carried out in these mouthwashes at 37 °C for 1, 4, 7, and 14 days, and the ions released were determined by inductively coupled plasma-mass spectrometry (ICP-MS). All wires were observed by scanning electron microscopy (SEM). The results showed a moderate ion release in the stainless steel wires, with nickel and chromium values of 500 and 1000 ppb in the worst conditions for the wires: concentrations of 380 ppm fluoride and 14 days of immersion. However, in the Ti-Mo and NiTi alloys, an abrupt change in release was observed when the samples were immersed in 380 ppm fluoride concentrations. Titanium releases in Ti-Mo wires reached 200,000 ppb, creating numerous pits on the surface. Under the same conditions, the release of Ni and Ti ions from the superelastic wires also exceeded 220,000 ppb and 180,000 ppb, respectively. This release of ions causes variations in the chemical composition of the wires, causing the appearance of martensite plates in the austenitic matrix after 4 days of immersion. This fact causes it to lose its superelastic properties at a temperature of 37 °C. In the case of immersion in 380 ppm mouthwashes for more than 7 days, rich-nickel precipitates can be seen. These embrittle the wire and lose all tooth-correcting properties. It should be noted that the release of Ni ions can cause hypersensitivity in patients, particularly women. The results indicate that the use of mouthwashes with a high content of fluoride should not be recommended with orthodontic archwires.
Topics: Female; Humans; Fluorides; Mouthwashes; Nickel; Orthodontic Wires; Stainless Steel; Surface Properties; Titanium; Male
PubMed: 36833476
DOI: 10.3390/ijerph20042780 -
The Angle Orthodontist Jan 2010To evaluate the quantitative effects on torque expression of varying the slot size of stainless steel orthodontic brackets and the dimension of stainless steel wire, and... (Review)
Review
OBJECTIVE
To evaluate the quantitative effects on torque expression of varying the slot size of stainless steel orthodontic brackets and the dimension of stainless steel wire, and to analyze the limitations of the experimental methods used.
MATERIALS AND METHODS
In vitro studies measuring torque expression in conventional and self-ligating stainless steel brackets with a torque-measuring device, with the use of straight stainless steel orthodontic wire without second-order mechanics and without loops, coils, or auxiliary wires, were sought through a systematic review process.
RESULTS
Eleven articles were selected. Direct comparison of different studies was limited by differences in the measuring devices used and in the parameters measured. On the basis of the selected studies, in a 0.018 inch stainless steel bracket slot, the engagement angle ranges from 31 degrees with a 0.016 x 0.016 inch stainless steel archwire to 4.6 degrees with a 0.018 x 0.025 inch stainless steel archwire. In a 0.022 inch stainless steel bracket slot, the engagement angle ranges from 18 degrees with a 0.018 x 0.025 inch stainless steel archwire to 6 degrees with a 0.021 x 0.025 inch stainless steel archwire. Active stainless steel self-ligating brackets demonstrate an engagement angle of approximately 7.5 degrees, whereas passive stainless steel self-ligating brackets show an engagement angle of approximately 14 degrees with 0.019 x 0.025 inch stainless steel wire in a 0.022 inch slot.
CONCLUSIONS
The engagement angle depends on archwire dimension and edge shape, as well as on bracket slot dimension, and is variable and larger than published theoretical values. Clinically effective torque can be achieved in a 0.022 inch bracket slot with archwire torsion of 15 to 31 degrees for active self-ligating brackets and of 23 to 35 degrees for passive self-ligating brackets with a 0.019 x 0.025 inch stainless steel wire.
Topics: Dental Alloys; Humans; Materials Testing; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Stainless Steel; Surface Properties; Torque; Torsion, Mechanical
PubMed: 19852662
DOI: 10.2319/080508-352.1 -
The Angle Orthodontist May 2010To evaluate the clinical differences in relation to the use of self-ligating brackets in orthodontics. (Review)
Review
OBJECTIVE
To evaluate the clinical differences in relation to the use of self-ligating brackets in orthodontics.
MATERIALS AND METHODS
Electronic databases were searched; no restrictions relating to publication status or language of publication were applied. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) investigating the influence of bracket type on alignment efficiency, subjective pain experience, bond failure rate, arch dimensional changes, rate of orthodontic space closure, periodontal outcomes, and root resorption were selected. Both authors were involved in study selection, validity assessment, and data extraction. Disagreements were resolved by discussion.
RESULTS
Six RCTs and 11 CCTs were identified. Meta-analysis of the influence of bracket type on subjective pain experience failed to demonstrate a significant advantage for either type of appliance. Statistical analysis of other outcomes was unfeasible because of inadequate methodological design and heterogenous designs.
CONCLUSIONS
At this stage there is insufficient high-quality evidence to support the use of self-ligating fixed orthodontic appliances over conventional appliance systems or vice versa.
Topics: Controlled Clinical Trials as Topic; Humans; Meta-Analysis as Topic; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Randomized Controlled Trials as Topic; Research Design; Treatment Outcome
PubMed: 20050755
DOI: 10.2319/081009-454.1 -
International Journal of Nanomedicine 2020The aim of this study was to clinically evaluate adhesion on titanium dioxide-coated stainless steel orthodontic wires to decrease white-spot formation.
INTRODUCTION
The aim of this study was to clinically evaluate adhesion on titanium dioxide-coated stainless steel orthodontic wires to decrease white-spot formation.
METHODS
In this study, four groups of 17 patients each (n=68) aged 12-25 years participated. A titanium dioxide coating layer was deposited on 0.4572 mm stainless steel orthodontic wires using physical vapor deposition. The coated wires were randomly assigned to one jaw, and the opposite jaw received an uncoated wire as control. Patients were divided into groups according to the duration that wires were in their mouths: A) 1 week, B) 2 weeks, C) 3 weeks, and D) 4 weeks. Block randomization was used to assign patients to each group. At the end of the experiment, 20 mm of each wire (canine-to-canine area) was cut and cultured in -specific medium. The culture plates were placed in an incubator containing 5% CO for 72 hours at 37°C, and then colonies were counted. MTT was used to test the biocompatibility of the coated and uncoated wires. To evaluate the stability of the coated titanium dioxide layer on the wires, titanium concentration on the saliva was determined using inductively coupled plasma mass spectroscopy.
RESULTS
The Kruskal-Wallis test showed that there was no significant difference in colony counts among the coated wires during 1-4 weeks (<0.48). In the uncoated-wire groups, colonys count at week 1 were higher than weeks 24 -(<0.022). Wilcoxon's test showed that the number of colonies was significantly different in groups A and C, but there was no significant difference in groups B or D. MTT-assay results showed that there was not a significant difference between cell viability in the coated-wire group and the control. The Kruskal-Wallis test showed that there was no significant difference in titanium concentration in the studied groups (<0.834).
CONCLUSION
Application of titanium dioxide coating is effective in reducing bacterial adhesion at wire insertion.
Topics: Adolescent; Adult; Animals; Bacterial Adhesion; Child; Coated Materials, Biocompatible; Dogs; Humans; Materials Testing; Orthodontic Wires; Stainless Steel; Streptococcus mutans; Surface Properties; Titanium; Young Adult
PubMed: 33204086
DOI: 10.2147/IJN.S258440