scholarly journals Maxillary incisor retraction: evaluation of different mechanisms

2013 ◽  
Vol 18 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Antônio Carlos de Oliveira Ruellas ◽  
Matheus Melo Pithon ◽  
Rogério Lacerda dos Santos
Keyword(s):  
Stainless Steel ◽  
Heat Source ◽  
Analysis Of Variance ◽  
Steel Wire ◽  
The Other ◽  
Maxillary Incisor ◽  
Tukey Test ◽  
Group A ◽  
Incisor Retraction ◽  
Incisor Inclination

OBJECTIVE: To mechanically evaluate different systems used for incisors retraction. METHODS: Three different methods for incisors retraction using 0.019 x 0.025-in stainless steel wire were evaluated. The samples were divided into three groups: Group A (retraction arch with 7-mm high vertical hooks); Group G3 (elastic chain attached to the miniimplant and to the 3-mm stainless steel hook soldered to the retraction arch); Group G6 (elastic chain attached to the mini-implant and to the 6-mm stainless steel hook soldered to the retraction arch). A dental mannequin was used for evaluation in order to simulate the desired movements when the device was exposed to a heat source. The analysis of variance (ANOVA) and the Tukey test were used (p < 0.05). RESULTS: The results demonstrated that Groups G3 and G6 exhibited less extrusion and less incisor inclination during the retraction phase (p < 0.05). With regard to incisor extrusion, statistically significant differences were observed between Groups A and G3, and between Groups A and G6 (p < 0.05). Regarding incisor inclination, statistically significant differences were observed between the three systems evaluated (p < 0.05). CONCLUSIONS: Arches with 6-mm vertical hooks allow the force to be applied on the center of resistance of the incisors, thus improving mechanical control when compared with the other two systems.

Psychophysically Based Physical Capability Limits For Right Angle Power Tool Operation

2020 ◽  
Vol 64 (1) ◽  
pp. 910-914
Author(s):  
Jonathan Valencia ◽  
Joel Cort
Keyword(s):  
Analysis Of Variance ◽  
The Other ◽  
Mixed Design ◽  
Joint Orientation ◽  
Physical Capability ◽  
Subject Variables ◽  
Group A ◽  
Repeated Analysis ◽  
Post Hoc

A psychophysical methodology was utilized to examine 40 non-skilled female participants performing right-angle power tool (RAPT) fastening tasks. A combination of two between subject variables were examined for a total of four between-subject groups: joint orientation (horizontal and vertical planes) and joint hardness (hard and soft joints). Participants were evenly distributed into one of four joint orientation- hardness groups. Within each group, a combination of three fastening strategies and three fastening frequencies were performed by each participant. The chosen target torque determined the physical capability limits (PCL). A mixed-design repeated analysis of variance with Tukey’ significance post hoc test were used to determine any significance with the measured variables ( p<0.05). Fastening strategy and frequency influenced the chosen torque magnitude. Participants chose significantly higher target torques with the Turbo Tight strategy in comparison to the other two strategies. Furthermore, participants chose to accept lower target torques and forces as fastening frequency increased.

Comparison of Chemical Properties and Ni Release of Stainless Steel and Nickel Titanium Wires

2014 ◽  
Vol 884-885 ◽  
pp. 560-565 ◽  
Author(s):  
Wassana Wichai ◽  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Artificial Saliva ◽  
Steel Wire ◽  
Nickel Titanium ◽  
The Other ◽  
Stainless Steel Wire ◽  
Niti Wire ◽  
Titanium Wire ◽  
Niti Wires

Objective: This study aimed to determine the composition and corrosion resistance of stainless steel and nickel titanium (NiTi) archwires and to compare Ni released from simulated standard fixed orthodontic appliances ligated with stainless steel and NiTi wires in artificial saliva at pH 5.14 and pH 6.69. in 4 weeks at 37oC. Materials and Method: Two commercial rectangular wires, 0.016 x 0.022 in size were studied, one Ormco stainless steel wire and another Ormco nickel titanium wire. Their composition was analyzed by an energy disporsive X-ray spectrometer (ESC) and their corrosion resistance was evaluated by a potentiodynamic polarization technique. For Ni release, the twenty-eight simulated fixed appliance sample sets were used, each corresponding to one half-maxillary arch. The samples were divided in 2 groups (14 sets per group). The first one was ligated to Ormco stainless steel archwires and the other one to Ormco NiTi archwires with elastomeric ligatures. Half sets of each group were immersed in 50 ml artificial saliva at pH 5.14 and the other half were immersed at pH 6.69. Ni release was quantified using flame atomic absorption spectrophotometry. Statistical analysis of variance (t-test) was determined on days 1, 4, 7, 9, 14, 21 and 28 comparing the amount of Ni released between groups. Results: Stainless steel wire was composed of Ni, Cr, Si, Mn and Fe while the nickel titanium wire was composed of Ti, Ni and Cr. NiTi wire has more percentage of Ni and therefore has less corrosion resistance than stainless steel wire. For Ni release, stainless steel and NiTi continuously increased at the time intervals for both pH levels. For group one, stainless steel wire had more Ni release at pH 5.14 and for the other group, NiTi wire had more Ni-release at pH 6.69. At 4 weeks, the Ni release of one half-maxillary arch was 1.383 ppm (1383 μg/l) at pH 5.14 and 1.079 ppm (1078 μg/l) at pH 6.69 for stainless steel wire while it was 1.221 ppm (1221 μg/l) at pH 5.14 and 1.267 ppm (1267μg/l) at pH 6.69 for NiTi wire. No significant difference was found in the amount of Ni release from stainless steel and NiTi wires at pH 5.14 and pH 6.69 in the different time intervals except on day 1 wherein the stainless steel archwire was significantly different (p<0.05) at pH 5.14 and pH 6.69. Conclusions: The NiTi wire had more Ni contain and less corrosion resistance than stainless steel wire. Stainless steel had more Ni release at pH 5.14 than pH 6.69 but NiTi had greater Ni release at pH 6.69 than pH 5.14.

scholarly journals Comparison of Apical Root Resorption encountered during Maxillary Incisor retraction using Stainless Steel Boot Loop and TMA Boot Loop – A Case Series

2016 ◽  
Vol 6 (1) ◽  
pp. 45-48
Author(s):  
Gaurav Gupta ◽  
Raj Kumar Singh ◽  
Ashima Relhan ◽  
Gurkeerat Singh ◽  
Abhishek Goyal
Keyword(s):  
Stainless Steel ◽  
Orthodontic Treatment ◽  
Root Resorption ◽  
Case Series ◽  
Maxillary Incisor ◽  
Apical Root Resorption ◽  
Incisor Retraction ◽  
External Apical Root Resorption

External apical root resorption (EARR) is probably the most common iatrogenic sequel of orthodontic treatment. The present case series focuses on the incisor retraction using frictionless mechanics. Boot loop made up of .019x.025 Stainless steel or TMA archwire were used for maxillary incisor retraction. Retraction with stainless steel boot loop showed greater root resorption as compared to TMA boot loop.Orthodontic Journal of Nepal, Vol. 6 No. 1, June 2016, pp.45-48 

scholarly journals Effectiveness of low binding frictional materials: Evaluation of the binding frictional resistance of improved superelastic nickel-titanium alloy wires with different bracket combinations

2019 ◽  
Vol 9 ◽  
pp. 156-164 ◽  
Author(s):  
Yoshio Shima ◽  
Akihiro Koyama ◽  
Motohiro Uo ◽  
Takashi Ono
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Orthodontic Treatment ◽  
Steel Wire ◽  
Frictional Resistance ◽  
Nickel Titanium ◽  
Test Results ◽  
Tukey Test ◽  
Frictional Materials ◽  
Multibracket Appliance

Introduction: This study aimed to evaluate the binding frictional resistance of improved superelastic nickel- titanium alloy wires (ISW) with different bracket combinations and to verify the effectiveness of low binding frictional materials by applying them in orthodontic treatment. Materials and Methods: Straight stainless steel wire (SSW; 0.016 × 0.022-inch) and straight ISW (0.016 × 0.022- inch) were set to each displaced bracket, and the tensile resistance load was measured. The maximum tensile resistance load was statistically compared using the Tukey test. For exemplification, we treated a typical extraction case of Angle Class I crowding malocclusion with lip protrusion using lower binding frictional materials, which were selected based on tensile test results. Results: The SSW and metal bracket combination had the largest maximum tensile resistance load, and the ISW and metal slot-equipped plastic bracket combination had the smallest load (P < 0.01). In a patient treated using lower binding frictional materials, the active treatment period was 9 months. Satisfactory patient results were obtained without using reinforced anchorage. Conclusions: Binding frictional resistance varies, depending on the archwire and bracket combination. In a multibracket appliance, selecting materials with as low a binding frictional resistance as possible may make a more effective treatment.

scholarly journals Evaluación de Extractos Vegetales y Bioinsecticidas Sobre Poblaciones de Spodoptera frugiperda y Elasmopalpus lignosellus en Maíz

2017 ◽  
Vol 13 (21) ◽  
pp. 238
Author(s):  
Teddy Landívar Ortiz ◽  
Eduardo Colina Navarrete ◽  
Carlos Castro Arteaga ◽  
Danilo Santana Aragoné ◽  
Guillermo García Vásquez ◽  
...  
Keyword(s):  
Experimental Design ◽  
Economic Analysis ◽  
Analysis Of Variance ◽  
Spodoptera Frugiperda ◽  
The Other ◽  
Hybrid Corn ◽  
Tukey Test ◽  
Elasmopalpus Lignosellus ◽  
Organic Insecticides ◽  
Higher Doses

The research was carried out on the Property “El Cartan” that is located in Km 4 way at Puebloviejo-Ventanas, county of Los Ríos. A test was conducted on the hybrid corn DK-1040. This test measures the response of the larvae of insects Spodoptera frugiperda and Elasmopalpus lignosellus to the application of dose of biological and organic insecticides. Also, the most appropriate dose in products was determined with an economic analysis. The experimental design used was random complete blocks with seven treatments and three replicates. The variables evaluated are: percentage of larvae control, number of larvae per plant, corn damage, and yield for hectare. The evaluated variables were subjected to the analysis of variance, and Tukey test was applied to 95 % probability. The analyzed results were determined to apply Neem (Azadirachtina indica) in dose of 1,0 L ha -1 . It diminishes the populations of S. frugiperda and E. lignosellus in relationship to the other active matters applied in the test. Higher doses lead to migration of pests to nearby hosts. The highest yield per hectare was found in the Neem 1.0 L ha-1 treatment with 8,940 kg ha-1.

Respiratory and stepping frequencies in conscious exercising cats

1981 ◽  
Vol 51 (4) ◽  
pp. 835-839 ◽  
Author(s):  
S. Iscoe
Keyword(s):  
Stainless Steel ◽  
Cross Correlation ◽  
Steel Wire ◽  
Respiratory Rhythm ◽  
Neural Circuitry ◽  
The Other ◽  
Stainless Steel Wire ◽  
Hamstring Muscles ◽  
Pattern Generators ◽  
The Right

The incidence of entrainment between respiratory and stepping frequencies has been investigated in exercising cats. Stainless steel wire electrodes were surgically implanted in the right hemidiaphragm, quadriceps, and hamstring muscles of six cats. Electromyograms were recorded while the cats were at rest or walking on a treadmill at speeds between 0.31 and 1.67 m/s (6 km/h). Autocorrelation of diaphragmatic activity showed cats to have two respiratory patterns: regular (maintained periodicity in the autocorrelogram) or irregular (flat autocorrelogram). Autocorrelation of quadriceps or hamstring activity revealed stepping frequency. Cross correlation of diaphragmatic vs. quadriceps or hamstring activities revealed the presence of entrainment between respiration and stepping. In four cats, entrainment was either very weak or absent, but the other two cats clearly showed entrainment of the two activities, even in the absence of a regular respiratory rhythm. In conclusion, at speeds up to 1.67 m/s, respiratory frequency is not tightly locked to stepping frequency in cats; however, the occurrence of entrainment in some instances clearly indicates the existence of neural circuitry linking these two pattern generators.

scholarly journals Comparison of anchorage capacity between implant and headgear during anterior segment retraction

2011 ◽  
Vol 81 (5) ◽  
pp. 915-922 ◽  
Author(s):  
F. Li ◽  
H. K. Hu ◽  
J. W. Chen ◽  
Z. P. Liu ◽  
G. F. Li ◽  
...  
Keyword(s):  
Treatment Duration ◽  
The Other ◽  
Maxillary Incisor ◽  
Controlled Trials ◽  
Cochrane Central Register ◽  
Positional Change ◽  
Anterior Teeth ◽  
Basal Bone ◽  
Anchorage Loss ◽  
Incisor Inclination

Abstract Objective: To compare the anchorage effects of the implants and the headgear for patients with anterior teeth retraction in terms of incisor retraction, anchorage loss, inclination of maxillary incisors, positional change of maxillary basal bone, and treatment duration. Materials and Methods: An electronic search for relative randomized controlled trials (RCTs) prospective and retrospective controlled trials was done through the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Medline, and CNKI, regardless of language of study. Study selection, methodological quality assessment, and data extraction were performed by two reviewers independently. Meta-analysis was performed when possible; otherwise descriptive assessment was done. Results: The search yielded 35 articles, of which eight met the inclusion criteria and were categorized into five groups according to types of intervention. For the midpalatal implant, the anchorage loss was much less than for the headgear group, with insignificant differences in terms of anterior teeth retraction, maxillary incisor inclination, positional change of basal bone, and treatment duration. For the mini-implant, greater anterior teeth retraction and less anchorage loss were demonstrated, with inconsistent results for the other measures. For the onplant, less anchorage loss was noted, with insignificant differences for the other measures. Conclusions: The skeletal anchorage of the midpalatal implant, mini-implant, and onplant offer better alternatives to headgear, with less anchorage loss and more anterior teeth retraction. There were inconsistent results from the included studies in terms of maxillary incisor inclination, positional change of maxillary basal bone, and treatment duration. More qualified RCTs are required to provide clear recommendations.

scholarly journals ANÁLISE FÍSICO-QUÍMICA E CONTAGEM DE COLIFORMES TOTAIS E TERMOTOLERANTES DE ALMÔNDEGAS ELABORADAS COM CARNE DE CAPIVARA E DIFERENTES CONCENTRAÇÕES DE BACON

2017 ◽  
Vol 13 (Especial 2) ◽  
pp. 35-40
Author(s):  
Gabriella Castro Cunha ◽  
Brena Cristine Rosário Silva ◽  
Diego da Silva Pedro ◽  
Vilson Matias Pinto ◽  
Márcio Ramatiz Lima dos Santos ◽  
...  
Keyword(s):  
Experimental Design ◽  
Analysis Of Variance ◽  
Titratable Acidity ◽  
The Other ◽  
Tukey Test ◽  
Physical Chemical ◽  
Level Of Significance

The objective of this study was to evaluate the quality of meatballs prepared with capybara meat and different concentrations of pork bacon. Three formulations of capybara meatballs were prepared: one with 100% of capybara meat and the other with 10 and 20% of pork bacon added. Coliforms were carried out at 35 and 45ºC of the meatball samples, in addition to pH, titratable acidity, moisture and ash determinations. In relation to the physical-chemical determinations, the results were submitted to analysis of variance and the differences of the means compared by Tukey test at the 5% level of significance. The results of the microbiological analyzes were evaluated in a descriptive way. The experimental design was completely randomized. All physicalchemical and microbiological determinations were performed in triplicate. Coliform analyzes showed that the meatballs were fit for consumption and the physicochemical results are in acceptable levels.

scholarly journals Evaluation of the marginal accuracy of provisional restorations made of acrylic resins

2019 ◽  
Vol 18 ◽  
pp. e191404
Author(s):  
Ísis Franco Pereira ◽  
Emilena Maria Castor Xisto Lima
Keyword(s):  
Analysis Of Variance ◽  
The Other ◽  
Marginal Adaptation ◽  
Finish Line ◽  
Acceptable Limit ◽  
Tukey Test ◽  
Acrylic Resins ◽  
Direct Technique ◽  
Marginal Discrepancy

Aim: To evaluate the marginal accuracy of provisional crowns made with acrylics resins and to identify the surface(s) with the highest marginal discrepancy. Methods: A direct technique was used to fabricate 96 provisional restorations with 8 materials: Dencrilay, Dencôrlay, Dencôr, Vipicor, Duralay, Resinlay Speed, Refine Bright and Alike (n=12). The provisional crowns were made on a prepared molar-shaped metal die with a vinyl polysiloxane impression as a matrix. Marginal discrepancy of provisional restorations was analyzed at buccal, lingual, mesial and distal surfaces of metal die finish line in a stereomicroscope lupe at 100X. The images obtained were transferred to the Corel Draw X7 program and the distances from the cervical margins of the specimen to the reference lines were measured vertically. Comparisons were made with 1-way analysis of variance and the Tukey test (p <0.05). Results: The Alike resin exhibited the lowest marginal discrepancy (0.018 mm) and was significantly different from the Dencôrlay (0.037 mm), Filter Bright (0.034 mm), Duralay (0.033 mm) and Vipicor (0.032) resins. The buccal surface showed the highest marginal discrepancy (0.040 mm) compared to those of other surfaces (distal 0.029mm, lingual 0.028mm and mesial 0.024mm). Conclusion: The marginal adaptation of all materials and surfaces tested in this study were within a clinical acceptable limit. The Alike resin showed the best performance compared to Dencôrlay, Refine Bright, Duralay, and Vipicor resins. The buccal surface showed the highest marginal discrepancy than those of the other tested surfaces.

Direct Metal Deposition of Stainless Steel Wire Using Metal Inert Gas as Heat Source for Repair Purposes

2011 ◽  
Vol 110-116 ◽  
pp. 3570-3574
Author(s):  
Nur Izan Syahriah Hussein ◽  
Mohd Seiful Ezuan Sayuti ◽  
Mohamad Nizam Ayof
Keyword(s):  
Stainless Steel ◽  
Heat Source ◽  
Steel Wire ◽  
Testing Machine ◽  
Optical Microscope ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Inert Gas ◽  
Microstructural Development ◽  
Deposition Parameter

Direct metal deposition (DMD) using wire feedstock than powder feeding offers potential advantages such as high material usage efficiency and deposition rate and therefore employed in this work. The deposition process was conducted using metal inert gas (MIG) as the heat source. This study involves manipulating one variable that is deposition parameter to determine if changes in this variable cause changes in another variable that is microstructure and hardness variation. The deposited material was characterized by means of optical microscope and Rockwell microhardness testing machine. In addition, Design Expert Software that implemented Response Surface Methodology (RSM) technique was used in determining optimization of parameters. Results from the software were compared to the results obtained from the experimental works. This study shows that the deposition parameters such as current, arc voltage and travel speed significantly affect the microstructural development and microhardness variations of the stainless steel deposited structure. At the end of this study, directions for future work were suggested in order to further enhance the microstructural and microhardness properties of deposited material.)

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