scholarly journals Evaluation of friction in metal, ceramic and self-ligating brackets submitted to sliding mechanics

2018 ◽  
Vol 47 (4) ◽  
pp. 244-248 ◽  
Author(s):  
Aryadne Cipreste MASCARELO ◽  
Ana Paula GODOI ◽  
Vivian FURLETTI ◽  
William CUSTÓDIO ◽  
Heloisa Cristina VALDRIGHI
Keyword(s):  
Frictional Force ◽  
Frictional Resistance ◽  
Base Plate ◽  
Test Machine ◽  
Acrylic Plate ◽  
Different Types ◽  
Metal Ceramic ◽  
Ceramic Bracket ◽  
Sliding Test ◽  
Sliding Mechanics

Abstract Objective With the purpose of evaluating the best results for a proposed orthodontic treatment, the aim of this research was to verify the frictional force between archwires and orthodontic brackets in sliding mechanics. Material and method Three different types of brackets were used: conventional metal, self-ligating metal and conventional polycrystalline esthetic type (n=10), totaling 30 brackets and .019 x .025 inches stainless steel rectangular wire. An acrylic plate was used. The wire was fixed to the brackets (conventional metal and conventional polycrystalline esthetic) with esthetic elastomeric ligation. The acrylic plate together with the 019 x 0.025 inches wire fitted to it was attached to the base plate of the Instron 4411 universal test machine so that it was positioned perpendicular to the ground. The bracket was drawn through the archwire segment at a speed of 5 mm / minute for a distance of 5 mm. For each type of bracket, ten tests were performed, with the bracket and archwire set being changed for each repetition. Data were analyzed by one-way Analysis of Variance (p <0.0001) and the Tukey Test (p <0.05). Result Convencional metal and self-ligating brackets presented similar friction (p>0.05), while ceramic bracket presented higher frictional resistance during sliding test (p<0.05). Conclusion It was concluded that the type of bracket influenced the frictional force value obtained, and better results were found when the metal and self-ligating brackets were used. The ceramic bracket presented a higher frictional force value.

The Influence of Bracket Material, Ligation Force and Wear on Frictional Resistance of Orthodontic Brackets

1993 ◽  
Vol 20 (2) ◽  
pp. 109-115 ◽  
Author(s):  
O. Keith ◽  
S. P. Jones ◽  
E. H. Davies
Keyword(s):  
Stainless Steel ◽  
Abrasive Wear ◽  
Single Crystal ◽  
Wear Debris ◽  
Aluminium Oxide ◽  
Frictional Resistance ◽  
Material Force ◽  
Orthodontic Bracket ◽  
Ceramic Brackets ◽  
Ceramic Bracket

Planar static frictional phenomena were investigated for two types of ceramic and one type of stainless steel orthodontic bracket against rectangular stainless steel archwire. The brackets studied were ‘Starfire’ (single crystal aluminium oxide), ‘Allure III’ (polycrystalline aluminium oxide), and ‘Dentaurum’ (stainless steel). The investigative parameters were: bracket material, force of ligation and whether the brackets were new or ‘worn’. Without exception, both types of ceramic bracket produced greater frictional resistance than the stainless steel brackets throughout testing. At a ligation force of 500 g, the Starfire bracket gave the greatest frictional resistance. At ligation forces of 200 and 50 g, the greatest frictional resistance was seen with Allure III. After a period of simulated wear, frictional resistance of Starfire tended to increase at the greatest ligation load while that of both ceramics decreased slightly at the two lower ligation loads. The ceramic brackets caused abrasive wear of the archwire surfaces and the consequent wear debris may have contributed to the changes in frictional resistance seen with Starfire and Allure III. Dentaurm brackets produced minimal frictional resistance in any test and negligible change with wear.

Identification of thermo-mechanical fatigue fracture location by transient thermal analysis for high-temperature operating SiC power module assembled with ZnAl eutectic solder

2018 ◽  
Vol 2018 (HiTEC) ◽  
pp. 000028-000031 ◽  
Author(s):  
Fumiki Kato ◽  
Hiroki Takahashi ◽  
Hidekazu Tanisawa ◽  
Kenichi Koui ◽  
Shinji Sato ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thermal Resistance ◽  
Thermal Cycle ◽  
Base Plate ◽  
Test Machine ◽  
Power Module ◽  
Eutectic Solder ◽  
Transient Thermal Analysis ◽  
The Individual ◽  
Transient Thermal

Abstract In this paper, we demonstrate that the structural degradation of a silicon carbide (SiC) power module corresponding to thermal cycles can be detected and tracked non-destructively by transient thermal analysis method. The purpose of this evaluation is to analyze the distribution of the thermal resistance in the power module and to identify the structure deterioration part. The power module with SiC-MOSFET were assembled using ZnAl eutectic solder as device under test. The individual thermal resistance of each part such as the SiC-die, the die-attachment, the AMCs, and the baseplate was successfully evaluated by analyzing the structure function graph. A series of thermal cycle test between −40 and 250°C was conducted, and the power modules were evaluated their thermal resistance taken out from thermal cycle test machine at 100, 200, 500 and 1000 cycles. We confirmed the increase in thermal resistance between AMCs and base plate in each thermal cycle. The portion where the thermal resistance increased is in good agreement with the location of the structural defect observed by scanning acoustic tomography (SAT) observation.

Thermal Effects on Wheel Performance Based on Twin Disc Testing

2020 ◽  
Author(s):  
Dingqing Li ◽  
Monique Stewart
Keyword(s):  
Thermal Effects ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Contact Forces ◽  
Rolling Contact ◽  
Test Machine ◽  
Testing Program ◽  
Different Types ◽  
Different Temperatures ◽  
Surface Performance

Abstract This paper presents the results and findings from a testing program conducted to investigate how temperature at the wheel-rail interface may affect wheel surface performance; i.e., development of rolling contact fatigue (RCF) and wear. Under this testing program, a twin disc test machine was used to test two different types of wheel specimens (cast and forged) under a range of temperatures (ambient to 800° F) and slip ratios from 0 to 0.75 percent. This testing program included a total of 32 tests, covering two wheel materials, four different temperatures, four slip ratios, and various traction coefficients as a ratio of longitudinal and vertical wheel/rail contact forces.

scholarly journals A novel customized ceramic bracket for esthetic orthodontics: in vitro study

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Liu Yang ◽  
Guangfu Yin ◽  
Xiaoming Liao ◽  
Xing Yin ◽  
Niansong Ye
Keyword(s):  
Shape Matching ◽  
Raw Materials ◽  
In Vitro Study ◽  
Frictional Resistance ◽  
Orthodontic Bracket ◽  
Wide Range ◽  
Ceramic Brackets ◽  
Orthodontic Patients ◽  
Ceramic Bracket

Abstract Background This study aims to develop a novel process to establish a standardized manufacturing technique of customized esthetic ceramic bracket system (CCB) which could be endowed with individual color and shape to satisfy patients’ individual demands. Material characteristics and mechanical parameters of CCB were evaluated. Subjects and methods CCB virtual models were designed individually according to patient’s teeth morphology and clinical demands. 3D printing technology, lost-wax technology, and selected glass-ceramic ingots were employed to fabricate CCB. Scanning electron microscopy (SEM) analyses were performed to characterize the surface morphology of CCB and commercially available brackets (Clarity Advanced; Crystalline VII; Inspire ICE; Damon Q). Static and kinetic frictional resistance (FR), shear bond strength (SBS) and adhesive remnant index (ARI) scores were recorded. One-way analyses of variance (ANOVA) and post-hoc Tukey’s HSD multiple tests were used for statistical analyses. Results Multi-color and multi-transparency raw materials facilitated CCB with a wide range of color options and controllable optical properties to satisfy different esthetic demands of individual orthodontic patients. CCB presented same level of FR as commercially available ceramic brackets did. No significant differences (P ≥ 0.05) of SBS were observed among CCB-ES (treated silane), Clarity Advanced and Crystalline VII groups, and CCB-E (no silane) attained the highest ARI mean score 3. In the preliminary clinical trial, CCB presented excellent color-matching and shape-matching appearances similar to natural teeth, which made it highly invisible from social intercourse distance. Conclusions CCB were demonstrated to be an applicable labial orthodontic bracket system with optimized esthetics and biomechanics. We envision that it would be an ideal alternative for patients who pursue esthetic orthodontic treatment but were not likely to take lingual appliances or clear aligners.

scholarly journals Cleansing orthodontic brackets with air-powder polishing: effects on frictional force and degree of debris

2016 ◽  
Vol 21 (4) ◽  
pp. 60-65 ◽  
Author(s):  
Brisa dos Santos Leite ◽  
Nathalia Carolina Fernandes Fagundes ◽  
Mônica Lídia Castro Aragón ◽  
Carmen Gilda Barroso Tavares Dias ◽  
David Normando
Keyword(s):  
Image Analysis ◽  
Comparative Analysis ◽  
Frictional Force ◽  
Orthodontic Treatment ◽  
Orthodontic Brackets ◽  
Wilcoxon Test ◽  
Control Group ◽  
And Control ◽  
Sliding Mechanics ◽  
Control Surfaces

ABSTRACT Introduction: Debris buildup on the bracket-wire interface can influence friction. Cleansing brackets with air-powder polishing can affect this process. Objective: The aim of this study was to evaluate the frictional force and amount of debris remaining on orthodontic brackets subjected to prophylaxis with air-powder polishing. Methods: Frictional force and debris buildup on the surface of 28 premolar brackets were evaluated after orthodontic treatment. In one hemiarch, each bracket was subjected to air-powder polishing (n = 14) for five seconds, while the contralateral hemiarch (n = 14) served as control. Mechanical friction tests were performed and images of the polished bracket surfaces and control surfaces were examined. Wilcoxon test was applied for comparative analysis between hemiarches at p < 0.05. Results: Brackets that had been cleaned with air-powder polishing showed lower friction (median = 1.27 N) when compared to the control surfaces (median = 4.52 N) (p < 0.01). Image analysis showed that the control group exhibited greater debris buildup (median = 2.0) compared with the group that received prophylaxis with air-powder polishing (median = 0.5) (p < 0.05). Conclusion: Cleansing orthodontic brackets with air-powder polishing significantly reduces debris buildup on the bracket surface while decreasing friction levels observed during sliding mechanics.

Enhancement of Tribological and Mechanical Behavior of Polyphenylene Sulfide Reinforced by Titanium Dioxide Nanoparticles

2016 ◽  
Vol 724 ◽  
pp. 20-27 ◽  
Author(s):  
A. Saad Najim ◽  
A. Kadhum Ola
Keyword(s):  
Friction Coefficient ◽  
Mechanical Behavior ◽  
Titanium Dioxide Nanoparticles ◽  
Polyphenylene Sulfide ◽  
Wear Volume ◽  
Test Machine ◽  
Melt Mixing ◽  
Pin On Disc ◽  
Sliding Test ◽  
The Impact

In present work, the influences of TiO2 nanoparticles addition on the tribological and mechanical behavior of polyphenylene sulfide (PPS) were investigated. The composites samples containing TiO2 nanoparticles at various percentages (0, 1, 3, and 6 wt. %) were prepared by melt mixing process using single screw extruder at 325 °C and 20 rpm. A pin-on-disc sliding test machine was used for measurement of wear volume and the friction coefficient. The counterface was made of steel carbide with roughness 0.1 μm Ra. The tests were run at a sliding speed of 0.4 m/s and 1 m/s, the contact pressure 0.65 Mpa with different sliding distances (5, 10, 15 and 20 km). Mechanical properties of PPS nanocomposites were studied to evaluate the influence of the nanoparticles addition, as well as examined the relation between the tribological and mechanical behavior. It was found that nanoparticles could further enhance the tribological properties. The lowest wear volume and friction coefficient was observed at 1 m/s was PPS+1wt. %, and for 0.4 m/s was observed in PPS+6wt. %. The results indicate that the mechanical of PPS nanocomposites have been improved, the impact strength and hardness increased with the incorporation of TiO2 nanoparticles. The density was also increased with TiO2 nanoparticles.

scholarly journals Surface roughness of three types of modern plastic bracket slot floors and frictional resistance

2013 ◽  
Vol 84 (1) ◽  
pp. 177-183 ◽  
Author(s):  
Sung-Hwan Choi ◽  
Da-Young Kang ◽  
Chung–Ju Hwang
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Three Dimensional ◽  
Frictional Resistance ◽  
Lower Surface ◽  
Reinforced Plastic ◽  
Ceramic Brackets ◽  
Sliding Test ◽  
Plastic Brackets

ABSTRACT Objective: To quantitatively analyze the surface roughness of the slot floors of three types of modern plastic brackets and to measure static frictional force during sliding mechanics in vitro. Materials and Methods: Control groups comprised stainless steel brackets and monocrystalline ceramic brackets. Test groups comprised three types of 0.022-in slot, Roth prescription, plastic, maxillary right central incisor brackets. Test groups included glass fiber-reinforced polycarbonate, filler-reinforced polycarbonate, and hybrid polymer with inserted metal slot brackets. The static frictional resistance caused by sliding movements with an archwire (stainless steel) in vitro was quantitatively analyzed. Both scanning electron microscope and three-dimensional optical surface profiling were used. Results: Scanning electron microscope and three-dimensional optical surface profiler revealed that all as-received brackets had irregular slot floor surfaces, and both irregularity and roughness increased after the archwire sliding test. The ceramic brackets in the control group showed significantly lower surface roughness values and higher frictional values during the archwire sliding test compared with the other brackets. The glass or filler-reinforced plastic brackets exhibited significantly higher static frictional values than the metallic slot type brackets (P &lt; .001). The hybrid polymer with inserted metal slot brackets showed relatively lower surface roughness and frictional values compared with the stainless steel control bracket. Conclusion: Glass or filler-reinforced plastic brackets showed higher frictional resistance than metallic slot–type brackets. A plastic bracket with inserted metal slot may be the best choice among plastic brackets for low frictional resistance and to avoid damage from sliding movements of the archwire.

scholarly journals The Impact of Different Types of Orthodontic Appliances and Its Location in Producing CT Scan Artefacts

2021 ◽  
Vol 50 (10) ◽  
pp. 3067-3075
Author(s):  
Mahmud Mohammed ◽  
Norma Ab. Rahman ◽  
Ahmad Hadif Zaidin Samsudin
Keyword(s):  
Stainless Steel ◽  
Image Quality ◽  
Orthodontic Brackets ◽  
Diagnostic Image Quality ◽  
Orthodontic Appliances ◽  
Diagnostic Image ◽  
Different Types ◽  
Polycrystalline Ceramic ◽  
The Mean ◽  
Ceramic Bracket

Fixed orthodontic appliances can produce metal artefacts in CT images which may degrade the diagnostic image quality. The study aimed to evaluate the artefacts based on the types and location of the metallic and non-metallic orthodontic brackets. This is an in-vitro cross-sectional study. Four different types of orthodontic brackets (stainless steel, titanium, monocrystalline, and polycrystalline ceramic bracket) were bonded consecutively in four different locations of the cadaveric skull. All scans were performed by a single operator using the same CT machine followed by a standard scanning protocol. Artefact intensity for all data sets was quantified by calculating the standard deviation (SD) of the grey values within the dataset by following a standard method. The One-way ANOVA Bonferroni test was used for the data analysis. The mean artefact score of the stainless steel bracket was significantly (p < 0.001) high in comparison with other types of the orthodontic brackets. Besides, the mean artefact score was significantly (p=0.002) low when orthodontic brackets were placed unilaterally. Stainless steel brackets produced a significant amount of noise in CT images which can degrade the diagnostic image quality. Thus, the polycrystalline ceramic bracket can be a better alternative of stainless steel brackets for patient need frequent CT scan.

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