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Sample records for standard bracketing technique

  1. Reproducibility of bracket positioning in the indirect bonding technique.

    Science.gov (United States)

    Nichols, Dale A; Gardner, Gary; Carballeyra, Alain D

    2013-11-01

    Current studies have compared indirect bonding with direct placement of orthodontic brackets; many of these have shown that indirect bonding is generally a more accurate technique. However, the reproducibility of an indirect bonding setup by an orthodontist has yet to be described in the literature. Using cone-beam computed tomography and computer-assisted modeling software, we evaluated the consistency of orthodontists in placing orthodontic brackets at different times. Five orthodontists with experience in indirect bonding were selected to place brackets on 10 different casts at 3 time periods (n = 30 per orthodontist). Each participant completed an initial indirect bonding setup on each cast; subsequent bracket placements were completed twice at monthly intervals for comparison with the initial setup. The casts were scanned using an iCAT cone-beam computed tomography scanner (Imaging Sciences International, Hatfield, Pa) and imported into Geomagic Studio software (Geomagic, Research Triangle Park, NC) for superimposition and analysis. The scans for each time period were superimposed on the initial setup in the imaging software, and differences between bracket positions were calculated. For each superimposition, the measurements recorded were the greatest discrepancies between individual brackets as well as the mean discrepancies and standard deviations between all brackets on each cast. Single-factor and repeated-measure analysis of variance showed no statistically significant differences between time points of each orthodontist, or among the orthodontists for the parameters measured. The mean discrepancy was 0.1 mm for each 10-bracket indirect bonding setup. Orthodontists are consistent in selecting bracket positions for an indirect bonding setup at various time periods. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  2. Comparative study on direct and indirect bracket bonding techniques regarding time length and bracket detachment

    Directory of Open Access Journals (Sweden)

    Jefferson Vinicius Bozelli

    2013-12-01

    Full Text Available OBJECTIVE: The aim of this study was to assess the time spent for direct (DBB - direct bracket bonding and indirect (IBB - indirect bracket bonding bracket bonding techniques. The time length of laboratorial (IBB and clinical steps (DBB and IBB as well as the prevalence of loose bracket after a 24-week follow-up were evaluated. METHODS: Seventeen patients (7 men and 10 women with a mean age of 21 years, requiring orthodontic treatment were selected for this study. A total of 304 brackets were used (151 DBB and 153 IBB. The same bracket type and bonding material were used in both groups. Data were submitted to statistical analysis by Wilcoxon non-parametric test at 5% level of significance. RESULTS: Considering the total time length, the IBB technique was more time-consuming than the DBB (p < 0.001. However, considering only the clinical phase, the IBB took less time than the DBB (p < 0.001. There was no significant difference (p = 0.910 for the time spent during laboratorial positioning of the brackets and clinical session for IBB in comparison to the clinical procedure for DBB. Additionally, no difference was found as for the prevalence of loose bracket between both groups. CONCLUSION: the IBB can be suggested as a valid clinical procedure since the clinical session was faster and the total time spent for laboratorial positioning of the brackets and clinical procedure was similar to that of DBB. In addition, both approaches resulted in similar frequency of loose bracket.

  3. Nuclear techniques to identify allergenic metals in orthodontic brackets

    International Nuclear Information System (INIS)

    Zenobio, E.G.; Zenobio, M.A.F.; Menezes, M.A.B.C.

    2009-01-01

    The present study determines the elementary alloy composition of ten commercial brands of brackets, especially related to Ni, Cr, and Co metals, confirmed allergenic elements. The nuclear techniques applied in the analyses were X-ray fluorescence (XRF) - Centre National de la Recherche Scientifique, France (National Center of Scientific Research), and X-ray energy spectrometry (XRES), and Instrumental Neutron Activation Analysis (INAA) - CDTN/CNEN, Brazil. The XRES and XRF techniques identified Cr in the 10 samples analyzed and Ni in eight samples. The INAA technique identified the presence of Cr (14% to 19%) and Co (42% to 2400 ppm) in all samples. The semi-quantitative analysis performed by XRF also identified Co in two samples. The techniques were effective in the identification of metals in orthodontic brackets. The elements identified in this study can be considered one of the main reason for the allergic processes among the patients studied. This finding suggests that the patients should be tested for allergy and allergenic sensibility to metals prior to the prescription of orthodontic device. (author)

  4. Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufacturing Techniques

    Science.gov (United States)

    2015-04-24

    images to ensure that brackets were not tilted. The images were calibrated and processed using Zen Pro 2011 commercial software (Carl Zeiss...Orthodontics. 5th ed. St. Louis: El Sevier Mosby; 2013: 369-370. 22. Reimann S et al. Material Testing of Reconditioned Orthodontic Brackets

  5. Modified precision lingual bonding technique: A step-wise approach with torque angulation device-bracket positioning device

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    Rosaline Tina Paul

    2017-01-01

    Full Text Available Objectives: Contemporary preadjusted edgewise appliance is all about the precision in bracket design, prescription and positioning in addition to the orthodontist's skill and training. However, achieving it is a bigger challenge as the anatomy of the lingual surface of a tooth is uneven, dissimilar, and moreover the tooth alignment on the lingual surface is variant. Thus, the need for an accurate method of bracket positioning with predetermined torque and angulation incorporated in the brackets according to the patients' need is of key importance. Materials and Methods: A TAD-BPD machine used to enhance the accuracy of bracket positioning and bioplast accurate tray transfer technique was used. Results: A step-wise procedures in bracket positioning and fabricating an indirect bonding tray for lingual orthodontics using the torque angulation device-bracket positioning device. Conclusions: This technique facilitated unhindered bonding even in severely crowded cases and easy rebonding during mid-treatment stages.

  6. Microleakage under Orthodontic Metal Brackets Bonded with Three Different Bonding Techniques with/without Thermocycling

    Directory of Open Access Journals (Sweden)

    Berahman Sabzevari

    2013-12-01

    Full Text Available Introduction: The aim of this study was to compare the microleakage of beneath the orthodontic brackets bonded with 3 different bonding techniques and evaluate the effect of thermocycling. Methods: One hundred and twenty premolars were randomly divided into 6 groups, received the following treatment: group 1: 37% phosphoric acid gel+Unite primer+Unite adhesive, group 2: 37% phosphoric acid gel+ Transbond XT primer+Transbond XT adhesive, group 3: Transbond plus Self Etching Primer (TSEP+Transbond XT adhesive. Groups 4, 5, and 6 were similar to groups 1, 2, and 3, respectively. Evaluation of microleakage was done following to thermocycling test. After bonding, the specimens were sealed with nail varnish except for 1 mm around the brackets and then stained with 0.5% basic fuchsine. The specimens were sectioned at buccolingual direction in 2 parallel planes and evaluated under a stereomicroscope to determine the amount of microleakage at bracket-adhesive and adhesive-enamel interfaces from gingival and occlusal margins. Results: Microleakage was observed in all groups, and increased significantly after thermocycling at some interfaces of Unite adhesive group and conventional etching+Transbond XT adhesive group, but the increase was not significant in any interface of TSEP group. With or without thermocycling, TSEP displayed more microleakage than other groups. In most groups, microleakage at gingival margin was significantly higher than occlusal margin. Conclusion: Thermocycling and type of bonding technique significantly affect the amount of microleakage.

  7. Alignment efficiency of standard versus tandem wire mechanics using conventional and self-ligating brackets: A pilot study

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    Prarthana Bhardwaj

    2017-01-01

    Full Text Available Objective: The objective of this study is to evaluate the clinical efficiency of 0.018″/0.022″ slot self-ligating (SL bracket system (standard and tandem mechanics in terms of rate of alignment by comparing it with a 0.022″ slot conventional ligating appliance system (MBT. Settings and Sample Population: The Department of Orthodontics. Materials and Methods: The pilot study was carried out using randomized controlled trial design. Forty patients having Little's irregularity index (II of 6–15 mm, treated by all first premolars extractions, were randomly allocated to 0.022″ slot conventional ligating bracket system, 0.018″ slot SL bracket system, 0.018″ slot SL bracket system (tandem archwires, 0.022″ slot SL bracket system, and 0.022″ slot SL bracket system (tandem archwires. The rate of alignment for each bracket system was measured from the difference in the II of serial casts taken at pretreatment and at the end of alignment, divided by the number of days between the two measurements. A one-way ANOVA model with post hoc Bonferroni multiple comparison procedures was used to identify intergroup differences. Results: The mean value of alignment efficiency was not found to be statistically significant in any of the five groups using digital models (P = 0.104. Conclusions: Alignment efficiency was not different between SL versus conventional ligating group, the 0.018″ slot versus 0.022″ slot and tandem versus standard mechanics.

  8. A Simplified Lingual Bracket Positioner

    Directory of Open Access Journals (Sweden)

    Sharath Kumar Shetty

    2014-01-01

    Full Text Available The indirect bonding system for lingual brackets may be broadly classified as; techniques using setup models and those using diagnostic models. The techniques using setup models are more accurate and many of them require the use of lingual bracket positioners for determining the correct position of brackets. We have devised a simpler yet reliable and effective bracket positioner ′Lingual Bracket Positioner′ in our department. Although many variants are available commercially, this design is easy to fabricate, cheap and ready to use.

  9. Radiographic technique and brackets affect measurements of proximal enamel thickness on mandibular incisors

    NARCIS (Netherlands)

    Ang, Amy Giok Phing; Steegmans, Pauline Antoinette Josephine; Kerdijk, Wouter; Livas, Christos; Ren, Yijin

    2017-01-01

    Objective: To investigate the influence of radiographic film and tube positioning, the presence and the size of brackets on in vitro measurements of proximal enamel thickness of mandibular incisors on periapical radiographs aimed to aid planning of interproximal enamel reduction procedures in

  10. [Ceramic brackets].

    Science.gov (United States)

    Mølsted, K

    1992-01-01

    Because of the many drawbacks of the hard and brittle material, ceramic brackets should not be used uncritically for orthodontic treatments. If ceramic brackets are used, the following guidelines should be observed: 1. If large and complicated tooth movements are involved, conventional bracket systems should be considered. 2. Occlusion on ceramic brackets is to be avoided. 3. Sharp instruments should be used with extreme care to avoid scratching the ceramic surface. Metal ligatures must not be used. 4. The length of the treatment is extended, probably because of the increased friction. 5. The problems connected with removing the brackets have not yet been solved. Be particularly careful of weakened teeth. 6. Esthetically, ceramic brackets function satisfactorily, but transparent elastic ligatures do not. They rapidly become discoloured and need frequent replacement. Nor are there as yet any "invisible arch wires", apart from some few, extremely flexible "white" arch wires. The ceramic bracket has no doubt come to stay, but there have been many difficulties in the "running-in" period, and the problems are far from solved yet. New ceramic brackets are coming onto the market all the time, and only future clinical studies can show whether they will become a genuine alternative to the conventional bracket.

  11. Bracketing effects on risk tolerance

    Directory of Open Access Journals (Sweden)

    Ester Moher

    2010-08-01

    Full Text Available Research has shown that risk tolerance increases when multiple decisions and associated outcomes are presented together in a broader ``bracket'' rather than one at a time. The present studies disentangle the influence of problem bracketing (presenting multiple investment options together from that of outcome bracketing (presenting the aggregated outcomes of multiple decisions, factors which have been deliberately confounded in previous research. In the standard version of the bracketing task, in which participants decide how much of an initial endowment to invest into each in a series of repeated, identical gambles, we find a problem bracketing effect but not an outcome bracketing effect. However, this pattern of results does not generalize to the cases of non-identical gambles nor discrete choice, where we fail to find the standard bracketing effect.

  12. Evaluation of shear bond strength of orthodontic brackets using trans-illumination technique with different curing profiles of LED light-curing unit in posterior teeth

    OpenAIRE

    Heravi, Farzin; Moazzami, Saied Mostafa; Ghaffari, Negin; Jalayer, Javad; Bozorgnia, Yasaman

    2013-01-01

    Background Although using light-cured composites for bonding orthodontic brackets has become increasingly popular, curing light cannot penetrate the metallic bulk of brackets and polymerization of composites is limited to the edges. Limited access and poor direct sight may be a problem in the posterior teeth. Meanwhile, effectiveness of the trans-illumination technique is questionable due to increased bucco-lingual thickness of the posterior teeth. Light-emitting diode (LED) light-curing unit...

  13. Analysis of mesiodistal angulations of preadjusted brackets

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    Marcos Rogério de MENDONÇA

    2014-08-01

    Full Text Available Manufacturers offer various prescriptions of preadjusted brackets for use in the “straight-wire” orthodontic technique. However, the need to incorporate bends in the rectangular wires during orthodontic finishing has led to concerns regarding the type of prescription chosen and the credibility of information provided by the manufacturer. The aim of this study was to compare the slot angulations of Roth prescription preadjusted metallic brackets for the maxillary left central incisor and maxillary left canine. For each tooth type, 10 brackets of three commercial brands (GAC, Forestadent and Morelli were selected. Two individual metal matrices for brackets and tooth positioning were made for each group of teeth. Captured images were obtained by standardized ortho-radial photography with a digital camera. Images were exported and analyzed with the Image J software package. One-way ANOVA and Tukey statistical analyses were performed at the 5% significance level. For brackets of the maxillary left central incisor, differences in mean angulation were observed between the Morelli and GAC groups (p < 0.01 and between the Forestadent and GAC groups (p < 0.01. For brackets of the maxillary left canine, differences in mean angulation were found between the Morelli and GAC groups (p < 0.01 and between the Morelli and Forestadent groups (p < 0.05. In conclusion, despite their same prescription name, the different brands exhibited significantly different angulation measurements.

  14. Enamel Surface Roughness after Debonding of Orthodontic Brackets and Various Clean-Up Techniques

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    Farzaneh Ahrari

    2013-01-01

    Full Text Available Objective: This study aimed to evaluate enamel roughness after adhesive removal using different burs and an Er:YAG laser.Materials and Methods: The buccal surfaces of forty human premolars were sealed by two layers of nail varnish, except for a circular area of 3 mm in diameter on the middle third. The enamel surfaces were initially subjected to profilometry analysis and four parameters of surface irregularity (Ra, Rq, Rt and Rz were recorded. Following bracket bonding and debonding, adhesive remnants were removed by tungsten carbide burs in low- or high- speed handpieces (group 1 and 2, respectively, an ultrafine diamond bur (group 3 or an Er:YAG laser (250 mJ, long pulse, 4 Hz (group 4, and surface roughness parameters were measured again. Then, the buccal surfaces were polished and the third profilometry measurements were performed.Results: The specimens that were cleaned with a low speed tungsten carbide bur showed no significant difference in surface irregularity between the different treatment stages (p>0.05. Surface roughness increased significantly after clean-up with the diamond bur and the Er:YAG laser (p<0.01. In comparison between groups, adhesive removal with tungsten carbide burs at slow- or high-speed handpieces produced the lowest, while enamel clean-up with the Er:YAG laser caused the highest values of roughness measurements (P<0.05.Conclusion: Under the study conditions, application of the ultrafine diamond bur or the Er:YAG laser caused irreversible enamel damage on tooth surface, and thus these methods could not be recommended for removing adhesive remnants after debonding of orthodontic brackets.

  15. ′An avant-garde indirect bonding technique for lingual orthodontics using the first complete digital "tad" (torque angulation device, & "BPD" (bracket positioning device′

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    Tushar Hegde

    2010-01-01

    This article covers an Indirect Bonding Technique using the Torque Angulation Device (TAD and the Bracket Positioning Device (BPD which ensure great accuracy while minimizing the poten- tial for error as compared to most methods available to the orthodontist today. This technique has been developed by taking into account the advantages and pitfalls of indirect bonding.

  16. Evaluation of shear bond strength of orthodontic brackets using trans-illumination technique with different curing profiles of LED light-curing unit in posterior teeth.

    Science.gov (United States)

    Heravi, Farzin; Moazzami, Saied Mostafa; Ghaffari, Negin; Jalayer, Javad; Bozorgnia, Yasaman

    2013-11-21

    Although using light-cured composites for bonding orthodontic brackets has become increasingly popular, curing light cannot penetrate the metallic bulk of brackets and polymerization of composites is limited to the edges. Limited access and poor direct sight may be a problem in the posterior teeth. Meanwhile, effectiveness of the trans-illumination technique is questionable due to increased bucco-lingual thickness of the posterior teeth. Light-emitting diode (LED) light-curing units cause less temperature rise and lower risk to the pulpal tissue. The purpose of this study was to evaluate the clinical effectiveness of trans-illumination technique in bonding metallic brackets to premolars, using different light intensities and curing times of an LED light-curing unit. Sixty premolars were randomly divided into six groups. Bonding of brackets was done with 40- and 80-s light curing from the buccal or lingual aspect with different intensities. Shear bond strengths of brackets were measured using a universal testing machine. Data were analyzed by one-way analysis of variance test and Duncan's post hoc test. The highest shear bond belonged to group 2 (high intensity, 40 s, buccal) and the lowest belonged to group 3 (low intensity, 40 s, lingual). Bond strength means in control groups were significantly higher than those in experimental groups. In all experimental groups except group 6 (80 s, high intensity, lingual), shear bond strength was below the clinically accepted values. In clinical limitations where light curing from the same side of the bracket is not possible, doubling the curing time and increasing the light intensity during trans-illumination are recommended for achieving acceptable bond strengths.

  17. Lazy & quarrelsome brackets

    NARCIS (Netherlands)

    Visser, A.

    1992-01-01

    In this paper we study two (kinds of) systems of brackets in an algebraic way. Lazy brackets have the same effect as introducing or eliminating 'a sufficient amount' of ordinary brackets at the same time. Quarrelsome brackets are brackets corresponding to different types of 'levels': think

  18. Adhesives for orthodontic bracket bonding

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    Déborah Daniella Diniz Fonseca

    2010-04-01

    Full Text Available The advent of acid etching, introduced by Buonocore in 1955, brought the possibility of bonding between the bracket base and enamel, contributing to more esthetic and conservative orthodontics. This direct bracket bonding technique has brought benefits such as reduced cost and time in performing the treatment, as well as making it easier to perform oral hygiene. The aim of this study was to conduct a survey of published studies on orthodontic bracket bonding to dental enamel. It was verified that resin composites and glass ionomer are the most studied and researched materials for this purpose. Resin-modified glass ionomer, with its biocompatibility, capacity of releasing fluoride and no need for acid etching on the tooth structure, has become increasingly popular among dentists. However, due to the esthetic and mechanical properties of light polymerizable resin composite, it continues to be one of the adhesives of choice in the bracket bonding technique and its use is widely disseminated.

  19. Material testing of reconditioned orthodontic brackets.

    Science.gov (United States)

    Reimann, S; Rewari, A; Keilig, L; Widu, F; Jäger, A; Bourauel, C

    2012-12-01

    While all manufacturers of orthodontic brackets label these products for single use, there are commercial providers offering bracket reconditioning (or "recycling"). We conducted this study to investigate the effects of different recycling techniques on material-related parameters in orthodontic brackets, aiming to derive indications for clinical use and conclusions about the biocompatibility, longevity, and application of recycled brackets. New metal brackets (equilibrium(®); Dentaurum, Ispringen, Germany) were compared to brackets recycled by different techniques, including direct flaming with a Bunsen burner, chemical reconditioning in an acid bath, a commercial unit (Big Jane; Esmadent, IL, USA), and outsourcing to a company (Ortho Clean, Dellstedt, Germany). Material-related examinations included the following: (1) corrosion behavior by static immersion testing and use of a mass spectrometer to determine nickel-ion concentrations in the corrosive medium, (2) surface features in scanning electron micrographs before and after corrosion testing, (3) Vickers hardness using a hardness testing machine, (4) shear bond strength as defined in DIN 13990-1, (5) dimensional stability of the bracket slots by light microscopy, and (6) frictional loss as assessed by an orthodontic measurement and simulation system (OMSS). Each examination was performed on ten brackets. Student's t-test was used for statistical analysis. Compared to the new brackets, those recycled in an acid bath or by a commercial provider revealed significant dimensional changes (p<0.05). Corrosion on the recycled brackets varied according to the recycling techniques employed. The group of brackets recycled by one company revealed hardness values that differed from those of all the other groups. No significant differences were observed in nickel-ion release, frictional loss, and shear bond strength. Recycling was found to significantly reduce the corrosion resistance and dimensional stability of

  20. Evaluation of stiffness and plastic deformation of active ceramic self-ligating bracket clips after repetitive opening and closure movements.

    Science.gov (United States)

    Carneiro, Grace Kelly Martins; Roque, Juliano Alves; Segundo, Aguinaldo Silva Garcez; Suzuki, Hideo

    2015-01-01

    The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip. Three types of active/interactive ceramic self-ligating brackets (n = 20) were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000), after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip. The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811). There were significant differences on stiffness among the three types of brackets (p = 0.005). The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle. Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation.

  1. Motivational Goal Bracketing

    DEFF Research Database (Denmark)

    Nafziger, Julia; Koch, Alexander

    It is a puzzle why people often evaluate consequences of choices separately (narrow bracketing) rather than jointly (broad bracketing). We study the hypothesis that a present-biased individual, who faces two tasks, may bracket his goals narrowly for motivational reasons. Goals motivate because th...... of the tasks. Narrow goals have a stronger motivational force and thus can be optimal. In particular, if one task outcome becomes known before working on the second task, narrow bracketing is always optimal.......It is a puzzle why people often evaluate consequences of choices separately (narrow bracketing) rather than jointly (broad bracketing). We study the hypothesis that a present-biased individual, who faces two tasks, may bracket his goals narrowly for motivational reasons. Goals motivate because...

  2. Bihamiltonian Cohomology of KdV Brackets

    NARCIS (Netherlands)

    Carlet, G.; Posthuma, H.; Shadrin, S.

    2016-01-01

    Using spectral sequences techniques we compute the bihamiltonian cohomology groups of the pencil of Poisson brackets of dispersionless KdV hierarchy. In particular, this proves a conjecture of Liu and Zhang about the vanishing of such cohomology groups.

  3. Are torque values of preadjusted brackets precise?

    Directory of Open Access Journals (Sweden)

    Alessandra Motta Streva

    Full Text Available OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º presented statistically significant difference from the proposed values (-7º. For the mandibular canines, American Orthodontics (-6.34º and Ortho Organizers (-6.25º presented statistically significant differences from the standards (-6º. Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

  4. The influence of bracket design on frictional losses in the bracket/arch wire system.

    Science.gov (United States)

    Schumacher, H A; Bourauel, C; Drescher, D

    1999-01-01

    In arch guided tooth movement, the essential role played by bracket configuration with respect to sliding friction has been recognized by the manufacturers, a fact which has had an increasing impact on the design and marketing of new bracket models in recent years. The aim of the present in-vitro study was to investigate the influence of different bracket designs on sliding mechanics. Five differently shaped stainless steel brackets (Discovery: Dentaurum, Damon SL: A-Company, Synergy: Rocky Mountain Orthodontics, Viazis bracket and Omni Arch appliance: GAC) were compared in the 0.022"-slot system. The Orthodontic Measurement and Simulation System (OMSS) was used to quantify the difference between applied force (NiTi coil spring, 1.0 N) and orthodontically effective force and to determine leveling losses occurring during the sliding process in arch guided tooth movement. Simulated canine retraction was performed using continuous arch wires with the dimensions 0.019" x 0.025" (Standard Steel, Unitek) and 0.020" x 0.020" (Ideal Gold, GAC). Comparison of the brackets revealed friction-induced losses ranging from 20 to 70%, with clear-cut advantages resulting from the newly developed bracket types. However, an increased tendency towards leveling losses in terms of distal rotation (maximum 15 degrees) or buccal root torque (maximum 20 degrees) was recorded, especially with those brackets giving the arch wire increased mobility due to their shaping or lack of ligature wire.

  5. Comparison of the frictional resistance between archwire and different bracket system: An in vitro study

    Directory of Open Access Journals (Sweden)

    Ajith R Pillai

    2014-01-01

    Full Text Available Background and Objectives: The purpose of this study is to evaluate the frictional resistance generated by conventional stainless steel, radiance ceramic bracket, self-ligating and composite brackets using a 0.019 × 0.025 stainless steel straight length wires in a 022 slot and to select brackets based on their frictional characteristic. Methodology: In order to conduct this study, four different types of bracket system were selected of the mclaughlin-bennet-trevesi (MBT discipline. They are Group 1 - stainless steel, Group 2 - composite bracket Group 3 - (American Orthodontics radiance ceramic bracket Group 4 - self-ligating bracket (SLB (Empower. In this study, five maxillary brackets of an arch of each type were used. All brackets are 0.022 × 0.028" in preadjusted edgewise appliance which simulates the dental arch. Five brackets were bonded to a stainless steel bar of dimension 150 mm × 25 mm × 3 mm. The bracket-arch wire units were submitted to mechanical test with an Instron universal testing machine 3365. A testing apparatus or holding jig was designed to hold the bracket during the mechanical test. Each sample was pulled at a speed of 6 mm for 1 min. Descriptive statistical information including mean and standard deviation of maximum friction force was calculated for each bracket wire combination. Interpretation and Conclusion: The SLB has the least friction among the four groups. The ceramic bracket showed the highest friction followed by stainless steel bracket, composite bracket, and SLB.

  6. Evaluation of stiffness and plastic deformation of active ceramic self-ligating bracket clips after repetitive opening and closure movements

    Directory of Open Access Journals (Sweden)

    Grace Kelly Martins Carneiro

    2015-08-01

    Full Text Available OBJECTIVE: The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip.METHODS: Three types of active/interactive ceramic self-ligating brackets (n = 20 were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000, after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip.RESULTS: The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811. There were significant differences on stiffness among the three types of brackets (p = 0.005. The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle.CONCLUSION: Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation.

  7. Impact of Orthodontic Brackets on the Intraoral Scan Data Accuracy

    Science.gov (United States)

    Park, Ji-Man; Choi, Shin-Ae; Myung, Ji-Yun; Chun, Youn-Sic

    2016-01-01

    This study aims to compare the impact of buccal and lingual brackets on the accuracy of dental arch data acquired by 4 different digital intraoral scanners. Two pairs of dental casts, one with buccal brackets and the other with lingual brackets, were used. Digital measurements of the 3D images were compared to the actual measurements of the dental models, which were considered standard values. The horizontal measurements included intercanine widths and intermolar widths. The Mann–Whitney U test was performed for comparisons. iTero® and Trios® both showed high accuracy with relatively small maximum deviation of measurements. iTero showed a significantly higher accuracy in most of the arch width measurements on the buccal bracket model than on the lingual model (P scanners should be used more cautiously in arches with lingual brackets than in those with buccal brackets. PMID:27999798

  8. Laser Guided Automated Calibrating System for Accurate Bracket ...

    African Journals Online (AJOL)

    appliance. When bands were used originally, Angle[1] thought the best position to place the bracket was at the center of the tooth. Later Ricketts[2] used ... In orthodontic literature, the advantages and disadvantages of ... Keywords: Hough transforms, Indirect bonding technique, Laser, Orthodontic bracket placement.

  9. Laser guided automated calibrating system for accurate bracket ...

    African Journals Online (AJOL)

    It is widely recognized that accurate bracket placement is of critical importance in the efficient application of biomechanics and in realizing the full potential of a preadjusted edgewise appliance. Aim: The purpose of ... placement. Keywords: Hough transforms, Indirect bonding technique, Laser, Orthodontic bracket placement ...

  10. Correlates of Narrow Bracketing

    DEFF Research Database (Denmark)

    Koch, Alexander; Nafziger, Julia

    We examine whether different phenomena of narrow bracketing can be traced back to some common characteristic and whether and how different phenomena are related. We find that making dominated lottery choices or ignoring the endowment when making risky choices are related phenomena and are both as...

  11. Comparative evaluation of efficacy of self-ligating interactive bracket with conventional preadjusted bracket: A clinical study

    Directory of Open Access Journals (Sweden)

    Balajee Jayachandran

    2016-01-01

    Full Text Available Aims and Objectives: This clinical study was conducted to compare the interactive self-ligating twin brackets and the standard double width brackets for their efficiency in Rate of Retraction. Materials and Methods: A total of 20 patients with Angle's class I or class II or class III dento-alveolar malocclusions between the age group of 18-25 years were selected. 10 patients in each group both males and females were randomly selected for the study. Ten patients were bonded using conventional brackets (Group I the other ten patients were bonded using Interactive self-ligating brackets (Group II. The Rate of retraction was quantified using the scanned models. Pretreatment and post treatment models were taken and scanned to measure the amount of Incisor movement and Anchor loss. Results: (1 Interactive Self-ligating brackets showed significant Rate of retraction when compared with conventional brackets on right and left quadrant. (Group I 0.545 ± .205: Group II 0.827 ± .208 P= .013* (Group I 0.598 ± .160: Group II 0.804 ± .268 P= .071 (2 Interactive self-ligating brackets when compared with conventional brackets had significant amount of incisor movement on right and left quadrant. (Group I 3.51 ± .548: Group II 4.38 ± .1.06 P= .047* and (Group I 3.66 ± .899: Group II 4.67 ± 1.02 P= .047* (3 Conventional brackets showed significant Amount of Anchor loss when compared with that of Interactive self-ligating brackets on right and left quadrant. (Group I .948 ± .392: Group II 0.501 ± .229 P= .013*. In the left side (Group I 0.861 ± .464: Group II 0.498 ± .227 P= .060. Conclusion: The interactive self-ligating brackets show more efficiency in Rate of Retraction, Amount of Incisor movement and Amount of Anchor loss when compared with the conventional brackets.

  12. Comparison of Frictional Forces Generated by a New Ceramic Bracket with the Conventional Brackets using Unconventional and Conventional Ligation System and the Self-ligating Brackets: An In Vitro Study.

    Science.gov (United States)

    Pasha, Azam; Vishwakarma, Swati; Narayan, Anjali; Vinay, K; Shetty, Smitha V; Roy, Partha Pratim

    2015-09-01

    Fixed orthodontic mechanotherapy is associated with friction between the bracket - wire - ligature interfaces during the sliding mechanics. A sound knowledge of the various factors affecting the magnitude of friction is of paramount importance. The present study was done to analyze and compare the frictional forces generated by a new ceramic (Clarity Advanced) bracket with the conventional, (metal and ceramic) brackets using unconventional and conventional ligation system, and the self-ligating (metal and ceramic) brackets in the dry condition. The various bracket wire ligation combinations were tested in dry condition. The brackets used were of 0.022″ × 0.028″ nominal slot dimension of MBT prescription: Stainless steel (SS) self-ligating bracket (SLB) of (SmartClip), SS Conventional bracket (CB) (Victory series), Ceramic SLB (Clarity SL), Conventional Ceramic bracket with metal slot (Clarity Bracket), Clarity Advanced Ceramic Brackets (Clarity(™) ADVANCED, 3M Unitek). These brackets were used with two types of elastomeric ligatures: Conventional Elastomeric Ligatures (CEL) (Clear medium mini modules) and Unconventional Elastomeric Ligatures (UEL) (Clear medium slide ligatures, Leone orthodontic products). The aligning and the retraction wires were used, i.e., 0.014″ nickel titanium (NiTi) wires and 0.019″ × 0.025″ SS wires, respectively. A universal strength testing machine was used to measure the friction produced between the different bracket, archwires, and ligation combination. This was done with the use of a custom-made jig being in position. Mean, standard deviation, and range were computed for the frictional values obtained. Results were subjected to statistical analysis through ANOVA. The frictional resistance observed in the new Clarity Advanced bracket with a conventional elastomeric ligature was almost similar with the Clarity metal slot bracket with a conventional elastomeric ligature. When using the UEL, the Clarity Advanced bracket

  13. ELISA technique standardization for strongyloidiasis diagnosis

    International Nuclear Information System (INIS)

    Huapaya, P.; Espinoza, I.; Huiza, A.; Universidad Nacional Mayor de San Marcos, Lima; Sevilla, C.

    2002-01-01

    To standardize ELISA technique for human Strongyloides stercoralis infection diagnosis a crude antigen was prepared using filariform larvae obtained from positive stool samples cultured with charcoal. Harvested larvae were crushed by sonication and washed by centrifugation in order to obtain protein extracts to be used as antigen. Final protein concentration was 600 μg/mL. Several kinds of ELISA plates were tested and antigen concentration, sera dilution, conjugate dilution and cut off were determined to identify infection. Sera from patients with both hyper-infection syndrome and intestinal infection demonstrated by parasitological examination were positive controls and sera from people living in non-endemic areas with no infection demonstrated by parasitological examination were negative controls. Best values were 5 μg/mL for antigen, 1/64 for sera, 1/1000 for conjugate; optical density values for positive samples were 1,2746 (1,1065 - 1,4206, DS = 0,3284) and for negative samples 0,4457 (0,3324 - 0,5538, DS = 0,2230). Twenty sera samples from positive subjects and one hundred from negative subjects were examined, obtaining 90% sensitivity and 88% specificity. The results show this technique could be useful as strongyloidiasis screening test in population studies

  14. [Precision of three-dimensional printed brackets].

    Science.gov (United States)

    Zhang, D; Wang, L C; Zhou, Y H; Liu, X M; Li, J

    2017-08-18

    This study was based on digital orthodontic diagnosis work flow for indirect bonding transfer tray model design and three-dimensional (3D) printing, and the aim of this paper was to inspect the dimensional accuracyof 3D printed brackets, which is the foundation of the follow up work and hoped that will illuminate the clinical application of the digital orthodontics work flow. The samples which consisted of 14 cases of patients with malocclusion from Department of Orthodontics Peking University were selected, including 8 cases with tooth extraction and 6 cases without tooth extraction. All the 14 patients were taken intra-oral scan (Trios 3Shape, Denmark) and cone-beam computed tomography (CBCT, NewTom 3G volumetric scanner, Aperio Service,Italy)shooting after periodontal treatment. STL data and DICOM data were obtained from intraoral scans and CBCT images.Data segmentation, registration, fusion, automatic tooth arrangement, virtual positioning of orthodontic appliance and conversion the coordinates of malocclusion model were all done with self-programming software. The data of 3D printing model with brackets on it were output finally and printed out with EDEN260V (Objet Geometries, Israel) to make indirect bonding transfer tray. Digital vernier caliper was used to measure the length and width of upper and lower left brackets and buccal tubes on those 3D models after removal of surrounding supporting material by ultrasonic vibration and water-spray. Intra-examiner reliability was assessed by using intra-class correlation coefficients (ICC), and one-sample T test was used to compare the measurements with the standard dimensional data of the brackets. There were significant differences which range in 0.04-0.17 mm between the 13 items out of the 19 measurement items. Except for the length of the lower left premolars'brackets, mean values of the other items were greater than the test value. Although the measurement results in the width of brackets and the width and

  15. In vitro tooth cleaning efficacy of electric toothbrushes around brackets

    OpenAIRE

    Schätzle, M.; Sener, B.; Schmidlin, P R.; Imfeld, T.; Attin, T.

    2017-01-01

    This in vitro study assessed the cleaning efficacy of different electric toothbrushes around upper incisor brackets. Standard and Mini Diamond™ brackets were fixed on black-stained teeth. The teeth were coated with white titanium oxide and brushed in a machine twice for 1 minute each. Twelve different brush heads with either a wiping or an oscillating-rotating action were tested. After brushing, the teeth were scanned, the black surfaces were assessed planimetrically and a modified plaque ind...

  16. Video Coding Technique using MPEG Compression Standards ...

    African Journals Online (AJOL)

    Some application areas of video compression focused on the problem of optimizing storage space and transmission bandwidth (BW). The two dimensional discrete cosine transform (2-D DCT) is an integral part of video and image compression, which is used in Moving Picture Expert Group (MPEG) encoding standards.

  17. Tooth angulation and dental arch perimeter-the effect of orthodontic bracket prescription.

    Science.gov (United States)

    Pontes, Luana F; Cecim, Rodolpho L; Machado, Sissy M; Normando, David

    2015-08-01

    The aim of this study was to evaluate the effects of upper incisors and canine angulations introduced by different bracket prescriptions on dental arch perimeter. Cone beam computerized tomography scans collected using I-Cat (Imaging Sciences International, Hatfield, PA, USA) were selected conveniently from a database of routine exams of a clinical radiology center. Crown and radicular measurements of upper incisors and canines were made and exported to the Autocad 2011 software to create a virtual dental model. The virtual teeth were positioned with an angulation of zero; thereafter, a reference value for the perimeter of the arch was measured. Furthermore, teeth angulations were applied according to the standards of the Edgewise bracket system and the Straight-wire systems: MBT, Capelozza, Andrews, and Roth. The largest linear distances for tooth crown (anterior arch perimeter) and root (radicular distance) were obtained for each bracket prescription. The anterior perimeter for well-aligned incisors and canines without angulation was used as reference (crown: 47.34mm; root: 39.13mm). An increase in the arch perimeter was obtained for all bracket prescriptions evaluated, which ranged from 0.28 and 3.19mm in the Edgewise technique, for the crown and root measurements, respectively, to 1.09 and 11.28mm for the Roth prescription. Bracket prescriptions with greater angulation led to an increased use of space within the dental arch, mainly in the radicular region. The consequence of this radicular angular displacement will need to be further investigated. © The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Invisible orthodontics part 3: aesthetic orthodontic brackets.

    Science.gov (United States)

    Waring, David; McMullin, Ailbhe; Malik, Ovais H

    2013-09-01

    In this, the third part of the series, aesthetic orthodontic treatment will be considered. The previous two articles have looked at invisible orthodontics with Invisalign and lingual brackets. This article will discuss the properties and use of aesthetic brackets, along with examples of orthodontic treatment cases using the aesthetic brackets. Increasing demand for aesthetics during orthodontic treatment has resulted in a significant increase in the use of aesthetic brackets. Clinicians need to be aware of the benefits and drawbacks of aesthetic brackets.

  19. Topological optimization of opening fence brackets on ring-stiffened cylindrical shell

    Directory of Open Access Journals (Sweden)

    SONG Xiaofei

    2018-02-01

    Full Text Available [Objectives] Stress concentration is prone to take place at connections between the opening fence and ring ribs of a ring-stiffened cylindrical shell under external pressure. [Methods] In this paper, a topological optimization method for the brackets that connect the fence to the ring ribs is proposed in order to effectively reduce the local high stress in the brackets. The sub-model technique is used to analyze the stress of the connecting brackets. In the design, the connection brackets are used as design variables and the stress of the shell, fence and ribs are used as constraints. The maximum stress of the bracket is minimized as the objective function. The topology optimization results are engineered to obtain the final form of the brackets. [Results] The calculation results show that brackets of which the panel is partially widened can effectively reduce the stress concentration position of the opening fence transverse offset if the side of the bracket away from the longitudinal section is longer; the opening fence is offset relative to the brackets, and the symmetrical design of the brackets is feasible. [Conclusions] This research provides a reference for similar structural design.

  20. In vitro tooth cleaning efficacy of manual toothbrushes around brackets.

    Science.gov (United States)

    Schätzle, Marc; Imfeld, Thomas; Sener, Beatrice; Schmidlin, Patrick R

    2009-02-01

    The purpose of this laboratory study was to assess the potential cleaning efficacy of nine different toothbrushes around brackets in vitro. Standard and Mini Diamond brackets were fixed on coloured teeth in a special model, coated with white titanium oxide, brushed in a machine with different manual toothbrushes (three different types: planar, staged, and v-shaped bristle field), and tested with a horizontal motion for 1 minute. After brushing, the teeth were scanned and the black surfaces were planimetrically assessed using a grey scale. Tooth areas which were black again after brushing indicated tooth surface contact of the filaments. The remaining white tooth areas around the brackets indicated 'plaque-retentive' niches. Statistical analysis was carried out using the Kruskal-Wallis one-way test of variance for individual comparison. Bonferroni adjustment was used for multiple testing, and comparison of bracket size with Wilcoxon signed rank test. In the most critical area of 2 mm around the brackets, there was no statistically significant difference between the different toothbrushes evaluated. The untouched area ranged from 11 to 26 per cent of the initially whitened tooth surface. By pooling the toothbrushes according to their design, the median cleaning efficacy of the v-shaped (73.1 per cent) and staged (75.6 per cent) toothbrushes resulted in significantly superior cleaning efficacy than planar toothbrushes (60.7 per cent) for standard brackets. For mini bracket type, staged toothbrushes showed a significantly better mean cleaning efficacy (77.8 per cent) than planar (65 per cent) and v-shaped (72.4 per cent) toothbrushes. Staged and v-shaped brush designs resulted in superior cleaning efficacy of teeth with fixed orthodontic attachments than toothbrushes with a planar bristle field. None of the tested toothbrushes showed a consistent, significantly higher cleaning efficacy than the others in this in vitro experiment.

  1. A new 2 D bracket positioning gauge

    Directory of Open Access Journals (Sweden)

    Bhuwan Saklecha

    2017-01-01

    Full Text Available Bracket positioning is the basic premise of pre-adjusted system, which allows the teeth to be placed with a straight wire into an occlusal contact with an excellent mesiodistal inclination (tip and excellent faciolingual inclination (torque. Improper bracket placement may lead to poorly placed teeth and necessitate bracket repositioning and archwire adjustments. This can lead to an increased treatment time or poor occlusion. Therefore, a bracket positioning gauge has been designed using both the planes and evaluated for its accuracy in bonding of brackets. It was found that the gauge not only helped in the placement of brackets accurately, but also reduced chairside time.

  2. Motivational Goal Bracketing: An Experiment

    DEFF Research Database (Denmark)

    Koch, Alexander; Nafziger, Julia

    a one-week period. Our theoretical model predicts (i) that weekly goals create incentives to compensate for a lower than desired performance today with the promise to work harder tomorrow, whereas daily goals exclude such excuses; (ii) that subjects with daily goals set higher goals in aggregate......We study in an online, real-effort experiment how the bracketing of non-binding goals affects performance in a work-leisure self-control problem. We externally induce the goal bracket - daily goals or a weekly goal - and within that bracket let subjects set goals for how much they want to work over...... and work harder than those with weekly goals. Our data support these predictions. Surprisingly, however, when goals are combined with an externally enforced commitment that requires subjects to spend less than a minute each day on the task to get started working, performance deteriorates because of high...

  3. Can 10% hydrofluoric acid be used for reconditioning of orthodontic brackets?

    Directory of Open Access Journals (Sweden)

    Daniela D Pompeo

    2016-01-01

    Conclusions: The aluminum oxide blasting technique was effective for the reconditioning of orthodontic brackets. Nevertheless, the reconditioning technique using 10% fluoridric acid for 60 s was not efficient for clinical use.

  4. Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.

    Science.gov (United States)

    Deguchi, T; Ito, M; Obata, A; Koh, Y; Yamagishi, T; Oshida, Y

    1996-07-01

    Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application.

  5. Standardization of P-33 by the TDCR efficiency calculation technique

    CSIR Research Space (South Africa)

    Simpson, BRS

    2004-02-01

    Full Text Available and Isotopes 60 (2004) 465?468 The standardization of 33P by the TDCR efficiency calculation technique B.R.S. Simpson*, W.M. Morris Radioactivity Standards Laboratory, CSIR?NML, 15 Lower Hope Road, Rosebank, Cape Town 7700, South Africa Abstract The activity... allowed). 2. Review of the TDCR efficiency calculation technique A LS source is viewed by a three-phototube detection system and the double-tube coincidence counting rate Nd and the triple-tube rate Nt are recorded simulta- neously. If N0 is the 33P...

  6. [How to write an andrological paper: standardization, mechanics and techniques].

    Science.gov (United States)

    Huang, Yu-Feng; Lu, Jin-Chun

    2010-12-01

    Andrological research papers not only reflect the current status and academic level of andrology, but also constitute an important communication platform for researchers and clinicians engaged in this field and contribute significantly to the development of andrology. It would be made easier to write a high-quality andrological paper once the author observes the basic requirements of research papers, adheres to the use of standard scientific terminology, knows the special writing mechanics, and equips himself with some essential writing techniques. Based on the long experience of editorship, we present a detailed introduction of the standardization, mechanics and techniques of writing an andrological paper.

  7. Paediatric sutureless circumcision-an alternative to the standard technique.

    LENUS (Irish Health Repository)

    2012-01-31

    INTRODUCTION: Circumcision is one of the most commonly performed surgical procedures in male children. A range of surgical techniques exist for this commonly performed procedure. The aim of this study is to assess the safety, functional outcome and cosmetic appearance of a sutureless circumcision technique. METHODS: Over a 9-year period, 502 consecutive primary sutureless circumcisions were performed by a single surgeon. All 502 cases were entered prospectively into a database including all relevant clinical details and a review was performed. The technique used to perform the sutureless circumcision is a modification of the standard sleeve technique with the use of a bipolar diathermy and the application of 2-octyl cyanoacrylate (2-OCA) to approximate the tissue edges. RESULTS: All boys in this study were pre-pubescent and the ages ranged from 6 months to 12 years (mean age 3.5 years). All patients had this procedure performed as a day case and under general anaesthetic. Complications included: haemorrhage (2.2%), haematoma (1.4%), wound infection (4%), allergic reaction (0.2%) and wound dehiscence (0.8%). Only 9 (1.8%) parents or patients were dissatisfied with the cosmetic appearance. CONCLUSION: The use of 2-OCA as a tissue adhesive for sutureless circumcisions is an alternative to the standard suture technique. The use of this tissue adhesive, 2-OCA, results in comparable complication rates to the standard circumcision technique and results in excellent post-operative cosmetic satisfaction.

  8. A-KAM, bracket positioning device

    Directory of Open Access Journals (Sweden)

    Anand Ambekar

    2018-01-01

    Full Text Available Bracket positioning is the heart of preadjusted edgewise appliance. Accuracy of bracket positioning directly affects the treatment outcome. A number of hand-held instruments are available for bracket positioning accuracy including Boon's gauge, MBT gauges, and various other modifications. However, the most commonly used MBT gauges come in a set of two or four jigs with gauges on each end of the instrument making it difficult to carry in the instrument tray for the orthodontists. Our new bracket positioning instrument, A-KAM, bracket positioning device surpasses these difficulties and can be used for reproducible bracket placement from 2.5 mm to 5.5 mm from the base of bracket.

  9. A novel wireless modulation technique for inter-standard communications

    NARCIS (Netherlands)

    Bekkaoui, A.; Haartsen, J.C.

    2006-01-01

    A new technique is presented with permits transceivers of different radio standards to communicate with each other. Applications are found in unlicensed bands where radios using different technologies, like for example Bluetooth, ZigBee, or WLAN IEEE 802.11, have to share the same radio spectrum. If

  10. Adhesive performance of precoated brackets after expiration.

    Science.gov (United States)

    Cloud, Cayce C; Trojan, Terry M; Suliman, Sam N; Tantbirojn, Daranee; Versluis, Antheunis

    2016-03-01

    To evaluate adhesive performance in terms of debonding forces of precoated metal and ceramic brackets 4 years after expiration. Buccal and lingual surfaces of embedded extracted maxillary premolars were etched with 34% Tooth Conditioner Gel (Dentsply Caulk, Milford, Del), rinsed, and dried. Transbond MIP (3M Unitek, Monrovia, Calif) was applied prior to placing adhesive precoated brackets (APC II Victory stainless steel and APC Plus Clarity ceramic brackets, 3M Unitek). The preexpiration brackets had 29-35 months before, and the postexpiration brackets were 45-52 months past, their expiration dates. Sample size was 17-21 per group. Debonding forces were determined by subjecting the bonded brackets to a shear force in a universal testing machine. Debonding forces were compared using two-way ANOVA. Debonded surfaces were examined under a stereomicroscope to determine failure modes, which were compared using the chi-square test. No statistically significant difference was found in debonding forces (P  =  .8581) or failure modes (P  =  .4538) between expired and unexpired brackets. Metal brackets required statistically significantly higher debonding forces than did ceramic brackets (P  =  .0001). For both expired and unexpired brackets, failure modes were mostly cohesive in the adhesive layer for ceramic brackets, and mixed between adhesive and cohesive failure in the adhesive layer for metal brackets. Adhesive precoated brackets did not have any reduction in enamel-adhesion properties up to 4 years after their expiration date. Extended shelf life testing for precoated dental brackets may be worth considering.

  11. The effects of silver coating on friction coefficient and shear bond strength of steel orthodontic brackets.

    Science.gov (United States)

    Arash, Valiollah; Anoush, Keivan; Rabiee, Sayed Mahmood; Rahmatei, Manuchehr; Tavanafar, Saeid

    2015-01-01

    Aims of the present study was to measure frictional resistance between silver coated brackets and different types of arch wires, and shear bond strength of these brackets to the tooth. In an experimental clinical research 28 orthodontic brackets (standard, 22 slots) were coated with silver ions using electroplate method. Six brackets (coated: 3, uncoated: 3) were evaluated with Scanning Electron Microscopy and Atomic Force Microscopy. The amount of friction in 15 coated brackets was measured with three different kinds of arch wires (0.019 × 0.025-in stainless steel [SS], 0.018-in stainless steel [SS], 0.018-in Nickel-Titanium [Ni-Ti]) and compared with 15 uncoated steel brackets. In addition, shear bond strength values were compared between 10 brackets with silver coating and 10 regular brackets. Universal testing machine was used to measure shear bond strength and the amount of friction between the wires and brackets. SPSS 18 was used for data analysis with t-test. SEM and AFM results showed deposition of a uniform layer of silver, measuring 8-10 μm in thickness on bracket surfaces. Silver coating led to higher frictional forces in all the three types of arch wires, which was statistically significant in 0.019 × 0.025-in SS and 0.018-in Ni-Ti, but it did not change the shear bond strength significantly. Silver coating with electroplating method did not affect the bond strength of the bracket to enamel; in addition, it was not an effective method for decreasing friction in sliding mechanics. © Wiley Periodicals, Inc.

  12. Effect of delayed polymerization time and bracket manipulation on orthodontic bracket bonding

    Science.gov (United States)

    Ponikvar, Michael J.

    This study examined the effect of bracket manipulation in combination with delayed polymerization times on orthodontic bracket shear bond strength and degree of resin composite conversion. Orthodontics brackets were bonded to extracted third molars in a simulated oral environment after a set period of delayed polymerization time and bracket manipulation. After curing the bracket adhesive, each bracket underwent shear bond strength testing followed by micro-Raman spectroscopy analysis to measure the degree of conversion of the resin composite. Results demonstrated the shear bond strength and the degree of conversion of ceramic brackets did not vary over time. However, with stainless steel brackets there was a significant effect (p ≤ 0.05) of delay time on shear bond strength between the 0.5 min and 10 min bracket groups. In addition, stainless steel brackets showed significant differences related to degree of conversion over time between the 0.5 min and 5 min groups, in addition to the 0.5 min and 10 min groups. This investigation suggests that delaying bracket adhesive polymerization up to a period of 10 min then adjusting the orthodontic bracket may increase both shear bond strength and degree of conversion of stainless steel brackets while having no effect on ceramic brackets.

  13. Shingle assembly with support bracket

    Science.gov (United States)

    Almy, Charles

    2007-01-02

    A shingle system, mountable to a support surface, includes overlapping shingle assemblies. Each shingle assembly comprises a support bracket, having upper and lower ends, secured to a shingle body. The upper end has an upper support portion, extending away from the shingle body, and an upper support-surface-engaging part, engageable with a support surface so that the upper edge of the shingle body is positionable at a first distance from the support surface to create a first gap therebetween. The lower end has a lower support portion extending away from the lower surface. The support brackets create: (1) a second gap between shingle bodies of the first and second shingle assemblies, and (2) an open region beneath the first shingle assembly fluidly coupling the first and second gaps.

  14. Adhesives for fixed orthodontic brackets.

    Science.gov (United States)

    Mandall, N A; Millett, D T; Mattick, C R; Hickman, J; Macfarlane, T V; Worthington, H V

    2003-01-01

    Bonding of orthodontic brackets to teeth is important to enable effective and efficient treatment with fixed appliances. The problem is bracket failure during treatment which increases operator chairside time and lengthens treatment time. A prolonged treatment is likely to increase the oral health risks of orthodontic treatment with fixed appliances one of which is irreversible enamel decalcification. To evaluate the effectiveness of different orthodontic adhesives for bonding. Electronic databases: the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Date of most recent searches: August 2002 (CENTRAL) (The Cochrane Library Issue 2, 2002). Trials were selected if they met the following criteria: randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing two different adhesive groups. Participants were patients with fixed orthodontic appliances. The interventions were adhesives that bonded stainless steel brackets to all teeth except the molars. The primary outcome was debond or bracket failure. Data were recorded on decalcification as a secondary outcome, if present. Information regarding methods, participants, interventions, outcome measures and results were extracted in duplicate by pairs of reviewers (Nicky Mandall (NM) and Rye Mattick (CRM); Declan Millett (DTM) and Joy Hickman (JH2)). Since the data were not presented in a form that was amenable to meta-analysis, the results of the review are presented in narrative form only. Three trials satisfied the inclusion criteria. A chemical cured composite was compared with a light cure composite (one trial), a conventional glass ionomer cement (one trial) and a polyacid-modified resin composite (compomer) (one trial). The quality of the trial reports was generally poor. It is difficult to draw any conclusions from this review, however, suggestions are made for methods of improving future research involving

  15. Frictional Characteristics of Active and Passive Self-Ligation Bracket Systems: An in vitro Study

    Directory of Open Access Journals (Sweden)

    K M Shahul Hameed Faizee

    2011-01-01

    Conclusion : Self-ligating brackets offered less frictional resistance than conventional brackets. Passive bracket systems offered less frictional resistance than active self-ligating bracket systems and Damon 3 brackets offered the least frictional resistance among all the brackets studied.

  16. Degenerate odd Poisson bracket on Grassmann variables

    International Nuclear Information System (INIS)

    Soroka, V.A.

    2000-01-01

    A linear degenerate odd Poisson bracket (antibracket) realized solely on Grassmann variables is proposed. It is revealed that this bracket has at once three Grassmann-odd nilpotent Δ-like differential operators of the first, second and third orders with respect to the Grassmann derivatives. It is shown that these Δ-like operators, together with the Grassmann-odd nilpotent Casimir function of this bracket, form a finite-dimensional Lie superalgebra

  17. Delayed bracket placement in orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Chandra Wigati

    2008-12-01

    Full Text Available Background: Beside bracket position, the timing of bracket placement is one of the most essential in orthodontic treatment with fixed appliances. Even it seems simple the timing of bracket placement can be crucial and significantly influence the result of orthodontic treatment. However it is often found brackets are placed without complete understanding of its purpose and effects, which could be useless and even detrimental for the case. Purpose: The aim of this case report is to show that the timing of bracket placement could be different depending on the cases. Case: Five different cases are presented here with different timing of bracket placement. Case management: On these cases, brackets were placed on the upper arch first, on the lower arch first, or even only on some teeth first. Good and efficient orthodontic treatment results were achieved. Conclusion: For every orthodontic case, from the very beginning of treatment, bracket should be placed with the end result in mind. If brackets are correctly placed at a correct time, better treatment result could be achieved without unnecessary round tripping tooth movement.

  18. DEBONDING OF CERAMIC BRACKETS BY ER:YAG LASER

    Directory of Open Access Journals (Sweden)

    Fidan ALAKUŞ-SABUNCUOĞLU

    2016-04-01

    Full Text Available Purpose: The objective of the present study is to evaluate the effects of Er:YAG laser debonding of ceramic brackets on the bond strength and the amount of adhesive resin remnant. Materials and Methods: Twenty human mandibular incisors were randomly divided into two groups of 10 and polycrystalline ceramic brackets (Transcend series 6000, 3M Unitek, Monrovia, CA, USA were bonded on enamel surfaces. Group 1 was the control group in which no laser application was performed prior to the shear bond strength (SBS testing. In Group 2, Er:YAG was applied in 3W power for 6 seconds using the scanning method. The brackets were tested for SBS with an Instron universal testing machine and results were expressed in megapascals (MPa. The amount of adhesive remnant was evaluated with Adhesive Remnant Index (ARI. One-way analysis of variance and Tukey’s post-hoc tests were used for statistical analysis. Results: Mean ± standard deviation of SBS values in the control group was 13.42 ±1.23 MPa and 8.47 ±0.71 MPa in the Er:YAG group and this difference was statistically significant (p<0.05. The evaluation of ARI scores demonstrated more adhesive was left on the enamel surface with Er:YAG group. Conclusion: 3W power Er:YAG laser application with the scanning method to polycrystalline ceramic brackets demonstrated lower bond strengths and higher ARI scores during the debonding procedure.

  19. Standardization of surgical techniques used in facial bone contouring.

    Science.gov (United States)

    Lee, Tae Sung

    2015-12-01

    Since the introduction of facial bone contouring surgery for cosmetic purposes, various surgical methods have been used to improve the aesthetics of facial contours. In general, by standardizing the surgical techniques, it is possible to decrease complication rates and achieve more predictable surgical outcomes, thereby increasing patient satisfaction. The technical strategies used by the author to standardize facial bone contouring procedures are introduced here. The author uses various pre-manufactured surgical tools and hardware for facial bone contouring. During a reduction malarplasty or genioplasty procedure, double-bladed reciprocating saws and pre-bent titanium plates customized for the zygomatic body, arch and chin are used. Various guarded oscillating saws are used for mandibular angloplasty. The use of double-bladed saws and pre-bent plates to perform reduction malarplasty reduces the chances of post-operative asymmetry or under- or overcorrection of the zygoma contours due to technical faults. Inferior alveolar nerve injury and post-operative jawline asymmetry or irregularity can be reduced by using a guarded saw during mandibular angloplasty. For genioplasty, final placement of the chin in accordance with preoperative quantitative analysis can be easily performed with pre-bent plates, and a double-bladed saw allows more procedural accuracy during osteotomies. Efforts by the surgeon to avoid unintentional faults are key to achieving satisfactory results and reducing the incidence of complications. The surgical techniques described in this study in conjunction with various in-house surgical tools and modified hardware can be used to standardize techniques to achieve aesthetically gratifying outcomes. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. A scanning electron microscopic investigation of ceramic orthodontic brackets

    International Nuclear Information System (INIS)

    McDonald, F.; Toms, A.P.

    1990-01-01

    Ceramic brackets were introduced to overcome the esthetic disadvantages of stainless steel brackets. The clinical impression of these brackets is very favorable. However, the sliding mechanics used in the Straightwire (A Company, San Diego, CA, USA) system appear to produce slower tooth movements with ceramic compared to stainless steel brackets. To determine whether this was due to any obvious mechanical problem in the bracket slot, Transcend (Unitek Corporation/3M, Monrovia, CA, USA) ceramic brackets were examined by a scanning electron microscope and compared to stainless steel brackets.Consistently, large surface defects were found in the ceramic bracket slots that were not present in the metal bracket slots. These irregularities could obviously hinder the sliding mechanics of the bracket slot-archwire system and create a greater demand on anchorage. Conversely, the fitting surface of the Transcend ceramic bracket showed extremely smooth surface characteristics, and it would seem advisable for the manufacturers to incorporate this surface within the bracket slot. (author)

  1. Dimensional reduction for generalized Poisson brackets

    Science.gov (United States)

    Acatrinei, Ciprian Sorin

    2008-02-01

    We discuss dimensional reduction for Hamiltonian systems which possess nonconstant Poisson brackets between pairs of coordinates and between pairs of momenta. The associated Jacobi identities imply that the dimensionally reduced brackets are always constant. Some examples are given alongside the general theory.

  2. Standardized fluoroscopy-based technique to measure intraoperative cup anteversion.

    Science.gov (United States)

    Zingg, Matthieu; Boudabbous, Sana; Hannouche, Didier; Montet, Xavier; Boettner, Friedrich

    2017-10-01

    Direct anterior approach (DAA) with the patient lying supine has facilitated the use of intraoperative fluoroscopy and allows for standardized positioning of the patient. The current study presents a new technique to measure acetabular component anteversion using intraoperative fluoroscopy. The current paper describes a mathematical formula to calculate true acetabular component anteversion based on the acetabular component abduction angle and the c-arm tilt angle (CaT). The CaT is determined by tilting the c-arm until an external pelvic oblique radiograph with the equatorial plane of the acetabular component perpendicular to the fluoroscopy receptor is obtained. CaT is determined by direct reading on the C-arm device. The technique was validated using a radiopaque synbone model comparing the described technique to computed tomography anteversion measurement. The experiment was repeated 25 times. The difference in anteversion between the two measuring techniques was on average 0.2° (range -3.0-3.1). The linear regression coefficients evaluating the agreement between the experimental and control methods were 0.99 (95%CI 0.88-1.10, p < 0.001) and 0.33 (95%CI -1.53-2.20, p = 0.713) for the slope and intercept, respectively. The current study confirms that the described three-step c-arm acetabular cup measuring technique can reproducibly and reliably assess acetabular component anteversion in the supine position, as compared to CT-imaging. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2307-2312, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  3. Femtosecond laser etching of dental enamel for bracket bonding.

    Science.gov (United States)

    Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk

    2013-09-01

    The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.

  4. Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations

    Directory of Open Access Journals (Sweden)

    Maria Regina Guerra MONTEIRO

    2014-06-01

    Full Text Available Objective: To compare the influence of archwire material (NiTi, beta-Ti and stainless steel and brackets design (self-ligating and conventional on the frictional force resistance. Material and Methods: Two types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and conventional brackets - Gemini, 3M/Unitek with three (0, 5, and 10 degrees slot angulation attached with elastomeric ligatures (TP Orthodontics were tested. All brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium, and stainless steel (Unitek/3M. The mechanical testing was performed with a universal testing machine eMIC DL 10000 (eMIC Co, Brazil. The wires were pulled from the bracket slots at a cross-head speed of 3 mm/min until 2 mm displacement. Results: Self-ligating brackets produced significantly lower friction values compared with those of conventional brackets. Frictional force resistance values were directly proportional to the increase in the bracket/ wire angulation. With regard to conventional brackets, stainless steel wires had the lowest friction force values, followed by nickel-titanium and beta-titanium ones. With regard to self-ligating brackets, the nickel-titanium wires had the lowest friction values, significantly lower than those of other materials. Conclusion: even at different angulations, the self-ligating brackets showed significantly lower friction force values than the conventional brackets. Combined with nickel-titanium wires, the self-ligating brackets exhibit much lower friction, possibly due to the contact between nickel-titanium clips and wires of the same material.

  5. LED vs halogen light-curing of adhesive-precoated brackets.

    Science.gov (United States)

    Mirabella, Davide; Spena, Raffaele; Scognamiglio, Giovanni; Luca, Lombardo; Gracco, Antonio; Siciliani, Giuseppe

    2008-09-01

    To test the hypothesis that bonding with a blue light-emitting diode (LED) curing unit produces no more failures in adhesive-precoated (APC) orthodontic brackets than bonding carried out by a conventional halogen lamp. Sixty-five patients were selected for this randomized clinical trial, in which a total of 1152 stainless steel APC brackets were employed. In order to carry out a valid comparison of the bracket failure rate following use of each type of curing unit, each patient's mouth was divided into four quadrants. In 34 of the randomly selected patients, designated group A, the APC brackets of the right maxillary and left mandibular quadrants were bonded using a halogen light, while the remaining quadrants were treated with an LED curing unit. In the other 31 patients, designated group B, halogen light was used to cure the left maxillary and right mandibular quadrants, whereas the APC brackets in the remaining quadrants were bonded using an LED dental curing light. The bonding date, the type of light used for curing, and the date of any bracket failures over a mean period of 8.9 months were recorded for each bracket and, subsequently, the chi-square test, the Yates-corrected chi-square test, the Fisher exact test, Kaplan-Meier survival estimates, and the log-rank test were employed in statistical analyses of the results. No statistically significant difference in bond failure rate was found between APC brackets bonded with the halogen light-curing unit and those cured with LED light. However, significantly fewer bonding failures were noted in the maxillary arch (1.67%) than in the mandibular arch (4.35%) after each light-curing technique. The hypothesis cannot be rejected since use of an LED curing unit produces similar APC bracket failure rates to use of conventional halogen light, with the advantage of a far shorter curing time (10 seconds).

  6. In vitro tooth cleaning efficacy of electric toothbrushes around brackets.

    Science.gov (United States)

    Schätzle, Marc; Sener, Beatrice; Schmidlin, Patrick R; Imfeld, Thomas; Attin, Thomas

    2010-10-01

    This in vitro study assessed the cleaning efficacy of different electric toothbrushes around upper incisor brackets. Standard and Mini Diamond brackets were fixed on black-stained teeth. The teeth were coated with white titanium oxide and brushed in a machine twice for 1 minute each. Twelve different brush heads with either a wiping or an oscillating-rotating action were tested. After brushing, the teeth were scanned, the black surfaces were assessed planimetrically and a modified plaque index for orthodontic patients (PIOP) was introduced. Tooth areas, which were black again after brushing indicated tooth surface contact of the filaments and were expressed as a percentage of total area. The remaining white areas around the brackets indicated 'plaque-retentive' niches. Analysis of variance was used for individual comparison of the brush types. Bonferroni/Dunn adjustment was applied for multiple testing. The Sonicare toothbrush handle with the brush head 'Compact ProResults' (81.7 per cent) and the brush head 'Standard ProResults' (80.8 per cent), as well as the sonic Waterpik toothbrush SR 800E with the standard brush head (78.2 per cent), showed statistically significantly better cleaning efficacy than all others. The poorest cleaning efficacy was observed for the oscillating-rotating Braun Oral-B Professional Care with the brush head 'Ortho' (less than 50 per cent). The planimetric findings were in correspondence with the results of the PIOP assessment. Cleaning efficacy of electric toothbrushes around brackets on upper incisors was different between the tested brushes. The PIOP was practicable, effective, and easy to use, although it has to be verified in a clinical study.

  7. Biocompatibility of nanosilver-coated orthodontic brackets: an in vivo study

    Directory of Open Access Journals (Sweden)

    Gamze Metin-Gürsoy

    2016-12-01

    Full Text Available Abstract Background Nanosilver particles of which antibacterial and antifungal properties have been shown in various in vitro and in vivo studies are used in many medical and dental fields for the prevention of infection. In this study, it is intended to evaluate the biocompatibility of nanosilver-coated brackets. Methods Nanosilver coating process was applied to the standard orthodontic brackets by a physical vapor deposition system. Brackets were coated with nanosilver particles of 1 μ thickness. A total of 12 Wistar Albino rats were included in the study (six and control (six groups. For the study and control groups, four nanosilver-coated and four standard brackets were aseptically implanted subcutaneously in the dorsal region of each rat. The brackets were removed with the surrounding tissues on days 7, 14, 30, and 60. The specimens were evaluated for inflammatory response. Results No significant difference was found in terms of tissue reaction between the study and control groups. On day 7, randomly distributed brown-black granules were seen in the granulation tissue adjacent to the bracket in the study group. These foreign particles continued along the bracket cavity in a few samples, but the inflammatory response was insignificant between the groups. Mast cell count was found to be significantly smaller only on day 7 in the study group than in the control group. Conclusions Nanosilver-coated orthodontic brackets were found to be similar with the standard type concerning inflammation. Further researches are needed with regard to the assessment of the brown-black granules, especially on the deposition of the vessel walls.

  8. The effect of ZnO nanoparticle coating on the frictional resistance between orthodontic wires and ceramic brackets

    Directory of Open Access Journals (Sweden)

    Ahmad

    2016-06-01

    Full Text Available Background. Any decrease in friction between orthodontic wire and bracket can accelerate tooth movement in the sliding technique and result in better control of anchorage. This study was carried out to evaluate frictional forces by coating orthodontic wires and porcelain brackets with zinc oxide nanoparticles (ZnO. Methods. In this in vitro study, we evaluated a combination of 120 samples of 0.019×0.025 stainless steel (SS orthodontic wires and 22 mil system edgewise porcelain brackets with and without spherical zinc oxide nanoparticles. Spherical ZnO nanoparticles were deposited on wires and brackets by immersing them in ethanol solution and SEM (scanning electron microscope evaluation confirmed the presence of the ZnO coating. The frictional forces were calculated between the wires and brackets in four groups: group ZZ (coated wire and bracket, group OO (uncoated wire and bracket, group ZO (coated wire and uncoated bracket and group OZ (uncoated wire and coated bracket. Kolmogorov-Smirnov, Mann-Whitney and Kruskal-Wallis tests were used for data analysis. Results. The frictional force in ZZ (3.07±0.4 N was the highest (P <0.05, and OZ (2.18±0.5 N had the lowest amount of friction (P <0.05 among the groups. There was no significant difference in frictional forces between the ZO and OO groups (2.65±0.2 and 2.70±0.2 N, respectively. Conclusion. Coating of porcelain bracket surfaces with ZnO nanoparticles can decrease friction in the sliding technique, and wire coating combined with bracket coating is not recommended due to its effect on friction.

  9. Reef Fish Survey Techniques: Assessing the Potential for Standardizing Methodologies.

    Directory of Open Access Journals (Sweden)

    Zachary R Caldwell

    Full Text Available Dramatic changes in populations of fishes living on coral reefs have been documented globally and, in response, the research community has initiated efforts to assess and monitor reef fish assemblages. A variety of visual census techniques are employed, however results are often incomparable due to differential methodological performance. Although comparability of data may promote improved assessment of fish populations, and thus management of often critically important nearshore fisheries, to date no standardized and agreed-upon survey method has emerged. This study describes the use of methods across the research community and identifies potential drivers of method selection. An online survey was distributed to researchers from academic, governmental, and non-governmental organizations internationally. Although many methods were identified, 89% of survey-based projects employed one of three methods-belt transect, stationary point count, and some variation of the timed swim method. The selection of survey method was independent of the research design (i.e., assessment goal and region of study, but was related to the researcher's home institution. While some researchers expressed willingness to modify their current survey protocols to more standardized protocols (76%, their willingness decreased when methodologies were tied to long-term datasets spanning five or more years. Willingness to modify current methodologies was also less common among academic researchers than resource managers. By understanding both the current application of methods and the reported motivations for method selection, we hope to focus discussions towards increasing the comparability of quantitative reef fish survey data.

  10. Compressed air injection technique to standardize block injection pressures.

    Science.gov (United States)

    Tsui, Ban C H; Li, Lisa X Y; Pillay, Jennifer J

    2006-11-01

    Presently, no standardized technique exists to monitor injection pressures during peripheral nerve blocks. Our objective was to determine if a compressed air injection technique, using an in vitro model based on Boyle's law and typical regional anesthesia equipment, could consistently maintain injection pressures below a 1293 mmHg level associated with clinically significant nerve injury. Injection pressures for 20 and 30 mL syringes with various needle sizes (18G, 20G, 21G, 22G, and 24G) were measured in a closed system. A set volume of air was aspirated into a saline-filled syringe and then compressed and maintained at various percentages while pressure was measured. The needle was inserted into the injection port of a pressure sensor, which had attached extension tubing with an injection plug clamped "off". Using linear regression with all data points, the pressure value and 99% confidence interval (CI) at 50% air compression was estimated. The linearity of Boyle's law was demonstrated with a high correlation, r = 0.99, and a slope of 0.984 (99% CI: 0.967-1.001). The net pressure generated at 50% compression was estimated as 744.8 mmHg, with the 99% CI between 729.6 and 760.0 mmHg. The various syringe/needle combinations had similar results. By creating and maintaining syringe air compression at 50% or less, injection pressures will be substantially below the 1293 mmHg threshold considered to be an associated risk factor for clinically significant nerve injury. This technique may allow simple, real-time and objective monitoring during local anesthetic injections while inherently reducing injection speed.

  11. Standard Establishment Through Scenarios (SETS): A new technique for occupational fitness standards.

    Science.gov (United States)

    Blacklock, R E; Reilly, T J; Spivock, M; Newton, P S; Olinek, S M

    2015-01-01

    An objective and scientific task analysis provides the basis for establishing legally defensible Physical Employment Standards (PES), based on common and essential occupational tasks. Infrequent performance of these tasks creates challenges when developing PES based on criterion, or content validity. Develop a systematic approach using Subject Matter Experts (SME) to provide tasks with 1) an occupationally relevant scenario considered common to all personnel; 2) a minimum performance standard defined by time, distance, load or work. Examples provided here relate to the development of a new PES for the Canadian Armed Forces (CAF). SME of various experience are selected based on their eligibility criteria. SME are required to define a reasonable scenario for each task from personal experience, provide occupational performance requirements of the scenario in sub-groups, and discuss and agree by consensus vote on the final standard based on the definition of essential. A common and essential task for the CAF is detailed as a case example of process application. Techniques to avoid common SME rating errors are discussed and advantages to the method described. The SETS method was developed as a systematic approach to setting occupational performance standards and qualifying information from SME.

  12. Comparative assessment of different recycling methods of orthodontic brackets for clinical use.

    Science.gov (United States)

    de Oliveira Correia, Ayla M; de Souza Matos, Felipe; Pilli Jóias, Renata; de Mello Rode, Sigmar; Cesar, Paulo F; Paranhos, Luiz R

    2017-06-01

    This study aimed to assess bond strength of the resin/bracket interface, under in-vitro shear stress, of metal brackets recycled by different clinical protocols. Sixty stainless steel orthodontic brackets were bonded on acrylic resin. The Transbond XT™ resin was applied at the base of the bracket aided by a matrix, obtaining 1 mm of thickness, and photoactivated with a LED device (40 s; 500 mW/cm2). Samples were randomly divided into four groups (N.=15) according to the reconditioning/recycling protocol: aluminum oxide (AO) 90 µm; hydrofluoric acid 60 s (HA60); hydrofluoric acid 120 s (HA120); hydrofluoric acid 60 s + silane (HA60S). After recycling, the resin was applied at the base of the bracket for shear testing in a universal testing machine (0.5 mm/min). After reconditioning/recycling, the surfaces were analyzed by Scanning Electron Microscopy. Data obtained after the shear test were subjected to ANOVA and Tukey's test (Precycling protocols (Precycling technique by aluminum oxide sandblasting was more effective for reconditioning orthodontic brackets when compared to the other protocols. The reconditioning technique with 10% hydrofluoric acid followed by the application of silane bonding agent may be used as an alternative protocol.

  13. Linear odd Poisson bracket on Grassmann variables

    International Nuclear Information System (INIS)

    Soroka, V.A.

    1999-01-01

    A linear odd Poisson bracket (antibracket) realized solely in terms of Grassmann variables is suggested. It is revealed that the bracket, which corresponds to a semi-simple Lie group, has at once three Grassmann-odd nilpotent Δ-like differential operators of the first, the second and the third orders with respect to Grassmann derivatives, in contrast with the canonical odd Poisson bracket having the only Grassmann-odd nilpotent differential Δ-operator of the second order. It is shown that these Δ-like operators together with a Grassmann-odd nilpotent Casimir function of this bracket form a finite-dimensional Lie superalgebra. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  14. Wronski Brackets and the Ferris Wheel

    Science.gov (United States)

    Martin, Keye

    2005-11-01

    We connect the Bayesian order on classical states to a certain Lie algebra on C^infty[0,1]. This special Lie algebra structure, made precise by an idea we introduce called a Wronski bracket, suggests new phenomena the Bayesian order naturally models. We then study Wronski brackets on associative algebras, and in the commutative case, discover the beautiful result that they are equivalent to derivations.

  15. Further validation of bracket pillar design methodology

    CSIR Research Space (South Africa)

    Vieira, F

    1998-07-01

    Full Text Available of seismic risk along the bracketed feature. Once an informed decision is made regarding the level of seismic risk to be accepted for a given layout, the rock engineer obtains from "design charts" a recommendable pillar width, assumed to keep the risk... for each area were produced. Seismic data from the selected site was processed and interpreted. Back analyses were carried out which attempted to compare modelling data and field seismic data for the actual bracket pillar layouts. Seismic moments...

  16. NET European Network on Neutron Techniques Standardization for Structural Integrity

    International Nuclear Information System (INIS)

    Youtsos, A.

    2004-01-01

    Improved performance and safety of European energy production systems is essential for providing safe, clean and inexpensive electricity to the citizens of the enlarged EU. The state of the art in assessing internal stresses, micro-structure and defects in welded nuclear components -as well as their evolution due to complex thermo-mechanical loads and irradiation exposure -needs to be improved before relevant structural integrity assessment code requirements can safely become less conservative. This is valid for both experimental characterization techniques and predictive numerical algorithms. In the course of the last two decades neutron methods have proven to be excellent means for providing valuable information required in structural integrity assessment of advanced engineering applications. However, the European industry is hampered from broadly using neutron research due to lack of harmonised and standardized testing methods. 35 European major industrial and research/academic organizations have joined forces, under JRC coordination, to launch the NET European Network on Neutron Techniques Standardization for Structural Integrity in May 2002. The NET collaborative research initiative aims at further development and harmonisation of neutron scattering methods, in support of structural integrity assessment. This is pursued through a number of testing round robin campaigns on neutron diffraction and small angle neutron scattering - SANS and supported by data provided by other more conventional destructive and non-destructive methods, such as X-ray diffraction and deep and surface hole drilling. NET also strives to develop more reliable and harmonized simulation procedures for the prediction of residual stress and damage in steel welded power plant components. This is pursued through a number of computational round robin campaigns based on advanced FEM techniques, and on reliable data obtained by such novel and harmonized experimental methods. The final goal of

  17. Applicative Characteristics of a New Zirconia Bracket with Multiple Slots

    Directory of Open Access Journals (Sweden)

    Koutaro Maki

    2016-01-01

    Full Text Available We have developed a new orthodontic bracket with three slots with lubricative properties on the working surfaces and proposed a new orthodontic treatment system employing 0.012−0.014-inch Ni-Ti arch wires. We recruited 54 patients, of which 27 received treatment with the new zirconia bracket with multiple slots system (M group, and the others received treatment with standard edge-wise appliances (control group [C group]. We compared the (1 tooth movement rate at the early stage of leveling; (2 changes in the dental arch morphology before and after leveling; and (3 pain caused by orthodontic treatment. Student’s t-test was used in all assessments. The tooth movement rate in the maxillomandibular dentition was higher in the M group. The basal arch width, anterior length, and the intercanine width in the maxillary dentition were not significantly different in the two groups; however, the intercanine width in the mandibular dentition was higher in the C group. In assessments of treatment-related pain, the visual analogue pain score was 56.0 mm and 22.6 mm in the C and M groups, respectively. A new zirconia bracket with multiple slots system provided better outcomes with respect to tooth movement rate, treatment period, and postoperative pain, thus indicating its effectiveness over conventional orthodontic systems.

  18. Comparison of multiple rebond shear strengths of debonded brackets after preparation with sandblasting and CO2 laser

    Directory of Open Access Journals (Sweden)

    Mojgan Kachoei

    2016-08-01

    Full Text Available Background. Failure of orthodontic bracket bonds is a common occurrence during orthodontic treatment. Different techniques have been suggested in the literature to remove resin residues from the bracket bases and enamel surfaces to prepare the surfaces again after debonding. This study attempted to compare multiple rebond shear strengths (SBS of debonded brackets following preparation with sandblasting and CO2 laser. Methods. The brackets were bonded on 30 human and bovine maxillary central incisors using self-curing composite resin. SBS was measured using Hounsfield testing machine. The brackets were rebonded for two other times after composite resin residues on their surfaces were removed, either with air abrasion or CO2 laser. The debonded brackets and enamel surfaces were also evaluated after each debonding procedure under a stereomicroscope in order to determine adhesive remnant index (ARI. SBS of debonded brackets after each step were compared between sandblast and CO2 laser groups. Results. We observed significant differences in SBS values between pre-recycling and first (P = 0.04, second (P = 0.007 and third recycling (P = 0.007 with laser. Recycling with sandblasting resulted in a decrease in SBS after the first and second recycling procedure; however, the SBS increased after the third recycling procedure, with no significant differences. Conclusion. SBS of brackets after recycling with sandblasting and laser beams was not significantly different, and both were at a favorable level. However, repeating the recycling procedure with sandblasting resulted in more favorable SBS compared to laser.

  19. Clinical Evaluation of Proclination of Lower Anterior Teeth during Alignment using a Single Width Bracket-A Pilot Study

    Science.gov (United States)

    Farhan, Azeem; Issar, Rashmi; Subramanian, Shashikala; Muniyappa, Manju Prasad; Ranjan, Shashi; Singh, Priyankar; Singh, Kumar Tathagat

    2016-01-01

    Introduction The pre-adjusted brackets are available in various prescriptions and sizes; nevertheless there are still many controversies as to which pre-adjusted edgewise bracket offers the maximum clinical efficiency. Aim This study was conducted to determine and compare the amount of lower incisor proclination during de-crowding if any of the Mini-Uni Twin Brackets with that of the standard double width brackets. Materials and Methods A total of 20 patients i.e., 10 patients in each group both males and females were randomly selected for the study from subjects seeking treatment, the selected samples were grouped as follows. Group I – Double Width Brackets (3M Unitek Gemini Series) 0.018” slot with Roth prescription. Group II – Mini Uni-Twin Bracket (3M Unitek) 0.018” slot with Roth prescription. Results The Mini-Uni Twin Brackets had statistically significant (p = 0.01) amount of proclination of the lower anteriors (0.8o± 0.3o) after de-crowding as compared to the standard Double Width Brackets and since the mean change in the Incisor Mandibular Plane Angle (IMPA) was lesser than 1o, its clinical significance could be questionable. Conclusion The Mini Uni Twin brackets are comparatively efficient in the lower anterior decrowding but further comparative clinical studies need to be performed on these Mini Uni Twin brackets, with an increase in the sample size and also the number of parameters to prove its total clinical efficiency. PMID:27504401

  20. In vitro study of color stability of polycrystalline and monocrystalline ceramic brackets

    Science.gov (United States)

    de Oliveira, Cibele Braga; Maia, Luiz Guilherme Martins; Santos-Pinto, Ary; Gandini Júnior, Luiz Gonzaga

    2014-01-01

    Objective The aim of this in vitro study was to analyze color stability of monocrystalline and polycrystalline ceramic brackets after immersion in dye solutions. Methods Seven ceramic brackets of four commercial brands were tested: Two monocrystalline and two polycrystalline. The brackets were immersed in four dye solutions (coffee, red wine, Coke and black tea) and in artificial saliva for the following times: 24 hours, 7, 14 and 21 days, respectively. Color changes were measured by a spectrophotometer. Data were assessed by Multivariate Profile Analysis, Analysis of Variance (ANOVA) and Multiple Comparison Tests of means. Results There was a perceptible change of color in all ceramic brackets immersed in coffee (ΔE* Allure = 7.61, Inspire Ice = 6.09, Radiance = 6.69, Transcend = 7.44), black tea (ΔE* Allure = 6.24, Inspire Ice = 5.21, Radiance = 6.51, Transcend = 6.14) and red wine (ΔE* Allure = 6.49, Inspire Ice = 4.76, Radiance = 5.19, Transcend = 5.64), but no change was noticed in Coke and artificial saliva (ΔE coffee, black tea and red wine. However, the same crystalline structure, either monocrystalline or polycrystalline, do not follow the same or a similar pattern in color change, varying according to the bracket fabrication, which shows a lack of standardization in the manufacturing process. Coffee dye produced the most marked color changes after 21 days of immersion for most ceramic brackets evaluated. PMID:25279530

  1. Intrapulpal Temperature Increase During Er:YAG Laser-Aided Debonding of Ceramic Brackets.

    Science.gov (United States)

    Yilanci, Hilal; Yildirim, Zeynep Beyza; Ramoglu, Sabri Ilhan

    2017-04-01

    The purpose of this study was to evaluate the temperature changes in the pulp chamber while using a newly introduced application of Er:YAG laser to debond ceramic brackets in a study model with a pulpal circulation with and without thermocycled samples. An esthetic alternative to stainless steel brackets, ceramic brackets have been proposed. However, because of their low fracture resistance and high bond strengths, ceramic brackets can cause a problem when they are being removed using conventional techniques. Experimental Groups A and B were established for samples with or without thermocycling. The same 20 maxillary central incisor and 20 premolar teeth were used in both groups. Pulpal blood microcirculation was simulated using an apparatus described in a previous study. Monocrystalline brackets were bonded by using Transbond XT. In Group A, brackets were debonded using the Er:YAG laser (600 mJ, 2 Hz, long pulse, and no air or water spray) after being stored in distilled water for 24 h. In Group B, brackets were debonded using the same laser system as that used in Group A after being stored in distilled water for 24 h and then thermocycled for a total of 5000 cycles between 5°C and 55°C. The laser irradiation duration and intrapulpal temperature changes were measured. In Group B, the intrapulpal temperature increase of the central incisors was significantly higher than that of the premolar teeth. In the central incisor and premolar teeth groups, there were no statistically significant difference between Groups A and B (p > 0.05). A positive correlation was found between laser irradiation duration and temperature increase (p < 0.01). The use of Er:YAG laser is an effective method for debonding the monocrystalline ceramic brackets. This method can be used safely under the consideration of intrapulpal temperature changes.

  2. [Study on standardization of cupping technique: elucidation on the establishment of the National Standard Standardized Manipulation of Acupuncture and Moxibustion, Part V, Cupping].

    Science.gov (United States)

    Gao, Shu-zhong; Liu, Bing

    2010-02-01

    From the aspects of basis, technique descriptions, core contents, problems and solutions, and standard thinking in standard setting process, this paper states experiences in the establishment of the national standard Standardized Manipulation of Acupuncture and Moxibustion, Part V, Cupping, focusing on methodologies used in cupping standard setting process, the method selection and operating instructions of cupping standardization, and the characteristics of standard TCM. In addition, this paper states the scope of application, and precautions for this cupping standardization. This paper also explaines tentative ideas on the research of standardized manipulation of acupuncture and moxibustion.

  3. Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study.

    Science.gov (United States)

    Mirzakouchaki, Behnam; Shirazi, Sajjad; Sharghi, Reza; Shirazi, Samaneh; Moghimi, Mahsan; Shahrbaf, Shirin

    2016-02-01

    Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets. 120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups. The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems. The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system. Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch.

  4. Avaliação da força de tração em braquetes colados pela técnica indireta com diferentes sistemas de adesão Evaluation of tensile strength of brackets bonded by indirect technique

    Directory of Open Access Journals (Sweden)

    André Tortamano

    2007-06-01

    Full Text Available OBJETIVO: o objetivo do presente estudo foi avaliar a resistência à tração de braquetes ortodônticos colados pela técnica indireta e pela técnica direta convencional. METODOLOGIA: foram utilizados 50 pré-molares humanos íntegros, recém-extraídos por motivos ortodônticos. Esses dentes foram divididos em 5 grupos, nos quais foram colados braquetes ortodônticos metálicos (Abzil-Brasil com as resinas compostas ortodônticas Concise (3M-Unitek-EUA e Transbond XT (3M-Unitek-EUA - utilizadas em ambas as técnicas, direta e indireta - e Transbond Sondhi (3M-Unitek-EUA - desenvolvida exclusivamente para a técnica indireta. O grupo I (controle I foi objeto de colagem direta com Transbond XT; no grupo II (controle II procedeu-se à colagem direta com Concise o grupo III recebeu colagem indireta com Concise; o grupo IV foi submetido à colagem indireta com Transbond XT e no grupo V foi realizada colagem indireta com Transbond Sondhi. Na técnica direta, o braquete foi colado diretamente sobre o esmalte após condicionamento ácido e aplicação de adesivo. Na técnica indireta, os braquetes foram colados primeiramente sobre modelo de gesso e depois transferidos para o dente, com o auxílio de moldeira individualizada. Os corpos-de-prova foram submetidos a testes de tração (Instron 4400 e os resultados foram objeto de testes estatísticos de análise de variância e de Tukey a 1%. RESULTADOS: os grupos III e V revelaram resultados significantemente menores que os dos dois grupos controles. CONCLUSÃO: a força obtida na colagem indireta com a resina Transbond XT não difere da força obtida na colagem direta com as resinas Concise e Transbond XT.AIM: The purpose of this study was to evaluate the bonding strength of brackets for direct and indirect bonding techniques. METHODS: Were used 50 human premolars recently extracted for orthodontic reasons. These teeth were divided in 5 groups and metalic orthodontic brackets (Abzil-Brazil were bonded

  5. Frictional Resistance of Three Types of Ceramic Brackets

    Directory of Open Access Journals (Sweden)

    Claire L Williams

    2014-01-01

    Full Text Available Objectives: To investigate the static frictional resistance at the bracket/archwire interface in two recently introduced bracket systems and compare them to conventional ceramic and conventional metal bracket systems. Three variables were considered including the bracket system, archwire type and archwire angulation. Material and Methods: Four bracket systems were tested in vitro: Self ligating ceramic, ceramic with metal slot and module, conventional ceramic with module and conventional metal with module. A specially constructed jig and an Instron testing machine were used to measure the static frictional resistance for 0.014 inches round and 0.018 x 0.025 inches rectangular stainless steel wires at 0° and 7° angulations. Main outcome measures: static frictional force at the bracket/archwire interface; recorded and measured in units of force (Newtons. Results: Self ligating ceramic and metal slot ceramic bracket systems generated significantly less static frictional resistance than conventional ceramic bracket systems with the wire at both angulations (P < 0.05. Changing the wire from 0.014 round to 0.018 x 0.025 rectangular wire significantly increased frictional forces for metal slot ceramic and conventional metal bracket systems (P < 0.01. Increasing wire angulation significantly increased frictional resistance at the bracket/archwire interface for all four types of bracket systems tested (P < 0.001. Conclusions: Compared to conventional ceramic, self ligating ceramic and metal slot ceramic bracket systems should give improved clinical performance, matching that of conventional metal brackets.

  6. Artifacts in orthodontic bracket systems in cone-beam computed tomography and multislice computed tomography.

    Science.gov (United States)

    Hirschinger, V; Hanke, S; Hirschfelder, U; Hofmann, E

    2015-03-01

    The purpose of this study was to quantify artifacts caused by different bracket systems in cone-beam computed tomography (CBCT) and multislice computed tomography (MSCT) scans. Orthodontic brackets of four different systems were consecutively bonded to the surface of a residual molar on a human cadaveric mandible. One MSCT system and three CBCT units were used to scan each of the four bonded brackets, in addition to obtaining a blank reference scan of the tooth surface. All datasets were registered to the reference dataset using visualization software (Analyze 11.0® by AnalyzeDirect). Artifact-related reductions in image quality were expressed in percent of theoretical maximum standard deviations (SD) obtained for the gray values of the adjacent voxels, with higher percentages correlating more pronounced artifacts. Both the SD percentages for three defined line profiles and their mean values were almost invariably higher with the MSCT system than with the CBCT units. Looking into the individual SD percentages, two of the CBCT units (Pax Zenith 3D® and Picasso Trio®; both Vatech) produced higher values than the MSCT system (SOMATOM Definition AS+®; Siemens) in some line profiles. The titanium bracket, in particular, was associated with marked differences between the two scanner technologies, as the mean artifact intensities from this bracket were particularly high with the MSCT unit and relatively low with the CBCT units. The artifact intensities observed with the other three bracket systems varied widely depending on which scanner was used. Different artifact intensities were noted depending on the composition of the bracket system and on the scanner technology (MSCT/CBCT). While the artifacts manifested themselves differently with different scanners, their adverse effects were comparable. However, given the variable severity of the artifacts observed depending on the materials scanned and the scanners used, a blanket recommendation for or against MSCT or CBCT

  7. A clinical and radiographic study to evaluate the rate of retraction of maxillary canine using nickel-titanium closed coil spring with two different bracket systems

    Directory of Open Access Journals (Sweden)

    P Adarsh Reddy

    2014-01-01

    Full Text Available Objectives: This study compares the efficiency of self-ligating brackets with the conventional preadjusted edgewise (PEA brackets during maxillary canine retraction using nickel-titanium closed coil springs. Materials and Methods: The sample comprised of 20 healthy patients (10 males and 10 females, within age groups 16-26 years (mean, 20 years having Class I malocclusion with bimaxillary protrusion. All patients underwent bilateral extraction of the maxillary first bicuspids and retraction of the maxillary canines with fixed self-ligating brackets (3M Smart clip and PEA appliance (3M Gemini. The initial records included standard intra- and extra-oral photographs, study models, lateral cephalograms, and panoramic radiographs. Results: The mean distal movement of canines in self-ligating brackets was 0.89 mm/mo with standard deviation of 0.255 and in preadjusted edgewise brackets, the mean distal movement of canines was 0.87 mm/mo with standard deviation of 0.214. The mean tipping of canine in self-ligating brackets was 7.45 ± 1.050(0 and in PEA brackets it was 7.70° ± 1.21°. The mean rotation of canine in self-ligating brackets was 7.65° ± 3.47° and in preadjusted edgewise appliance it was 12.30° ± 3.08°. Conclusion: The rates of distal movement of the maxillary canines were similar with both conventional and self-ligating brackets. Rotation of the maxillary canines during retraction was minimized with self-ligating brackets in comparison to conventional bracket systems.

  8. Technique for fabrication of gradual standards of radiographic image blachening density

    International Nuclear Information System (INIS)

    Borovin, I.V.; Kondina, M.A.

    1987-01-01

    The technique of fabrication of gradual standards of blackening density for industrial radiography by contact printing from a negative is described. The technique is designed for possibilities of industrial laboratoriesof radiation defectoscopy possessing no special-purpose sensitometric equipment

  9. 21 CFR 872.5470 - Orthodontic plastic bracket.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...

  10. Poisson brackets for fluids and plasmas

    International Nuclear Information System (INIS)

    Morrison, P.J.

    1982-01-01

    Noncanonical yet Hamiltonian descriptions are presented of many of the non-dissipative field equations that govern fluids and plasmas. The dynamical variables are the usually encountered physical variables. These descriptions have the advantage that gauge conditions are absent, but at the expense of introducing peculiar Poisson brackets. Clebsch-like potential descriptions that reverse this situations are also introduced

  11. 445-nm diode laser-assisted debonding of self-ligating ceramic brackets.

    Science.gov (United States)

    Stein, Steffen; Kleye, Alexander; Schauseil, Michael; Hellak, Andreas; Korbmacher-Steiner, Heike; Braun, Andreas

    2017-10-26

    This study determined the influence of irradiation on aesthetic ceramic brackets with a novel 445-nm diode laser prior to debonding on the bracket failure mode. Thirty ceramic brackets (In-Ovation® C, GAC) were standard-bonded to the oral and buccal planed and polished enamel surfaces of 15 caries-free human 3rd molars. Prior to study-blinded debonding, the brackets in the laser group were irradiated with the diode laser (SIROLaser Blue®, Sirona), while the irradiation was simulated within the conventional group. To determine the degree of enamel fractures and the adhesive remnant index (ARI) before debonding (T0), after debonding (T1) and after removal of the remaining composite using a rotating fraise (red ring, Comet) (T2), micrographs of the enamel surface at 10-fold and 20-fold magnifications were taken. Additionally, the enamel surface was investigated using seven randomly chosen samples from each group at every time point by SEM at 200-fold and 500-fold magnifications. In the laser group, the ARI-score was statistically significantly reduced (pdiode laser prior to debonding of ceramic brackets significantly changes bonding failure in terms of less remaining adhesive. This is of clinical importance as the risk of enamel fractures and chair time can be reduced.

  12. Basic prediction techniques in modern video coding standards

    CERN Document Server

    Kim, Byung-Gyu

    2016-01-01

    This book discusses in detail the basic algorithms of video compression that are widely used in modern video codec. The authors dissect complicated specifications and present material in a way that gets readers quickly up to speed by describing video compression algorithms succinctly, without going to the mathematical details and technical specifications. For accelerated learning, hybrid codec structure, inter- and intra- prediction techniques in MPEG-4, H.264/AVC, and HEVC are discussed together. In addition, the latest research in the fast encoder design for the HEVC and H.264/AVC is also included.

  13. Preliminary detection of explosive standard components with Laser Raman Technique

    International Nuclear Information System (INIS)

    Botti, S.; Ciardi, R.

    2008-01-01

    Presently, our section is leader of the ISOTREX project (Integrated System for On-line TRace EXplosives detection in solid, liquid and vapour state), funded in the frame of the PASR 2006 action (Preparatory Action on the enhancement of the European industrial potential in the field of Security Research Preparatory Action) of the 6. EC framework. ISOTREX project will exploit the capabilities of different laser techniques as LIBS (Laser Induced Breakdown Spectroscopy), LPA (Laser Photo Acustic) and CRDS (Cavity Ring Down Spectroscopy) to monitor explosive traces. In this frame, we extended our investigation also to the laser induced Raman effect spectroscopy, in order to investigate its capabilities and possible future integration. We analysed explosive samples in bulk solid phase, diluted liquid phase and as evaporated films over suitable substrate. In the following, we present the main results obtained, outlining preliminary conclusions [it

  14. Interactive edgewise mechanisms: form and function comparison with conventional edgewise brackets.

    Science.gov (United States)

    Voudouris, J C

    1997-02-01

    As the frequency of use of the interactive twin (I-twin) edgewise mechanisms and techniques become increasingly prevalent, it is important to consider how they compare with conventional twin (c-twin) edgewise bracket systems. Optimum intrabracket and interbracket forces in I-twins balance with capillary blood pressures. An unbiased, experimental in vitro, scanning electromicroscopy and in vivo clinical investigation of 83 patients was conducted to compare the frictional resistance of three different I-twin bracket systems, type A (Sigma, American Orthodontics), type B (Interactwin, Ormco Corp.), and type C (Damon, A-company) with three c-twins counterparts respectively types D, E, and F. The three interactive twin brackets were each self-seating by an integrated arm component and made significant incremental improvements to the conventional twins in three different ways. First, the I-twin types reduced frictional resistance by using arm engagement with a lower coefficient of friction and a reduced seating force against the arch wire. The reduced seating force friction produced initially small interbracket arch wire deflections for biocompatible tooth movement and, combined with a wide twin bracket, produced accurate rotation corrections. Reduced friction within the I-twin bracket consequently permitted the effective use of light forces for flowing biomechanics that maximized anchorage. In evaluating friction, two distinctly different interaction forces acting to seat the arch wire were also identified. Type A demonstrated active interaction with round arch wires that resulted in a low functional seating force responsible for early and complete tooth control in comparison to the high seating force of c-twins. Types B and C both showed passive interaction with seating force friction approximately equal to zero that required large rectangular dimension arch wires for full bracket expression. Second, a significant reduction in the time taken to change arch wires was

  15. Effect of Bracket Base Sandblasting on Bonding of Orthodontic Brackets on Enamel Surface

    Directory of Open Access Journals (Sweden)

    Mohammad Farahani

    2016-01-01

    Full Text Available Introduction: In evaluating bond failure, considerable attention has been paid to the various factors that affect bond strength. The bracket–resin interface is the site of usual bond failure. Therefore, many efforts have been accomplished on this interface. The aim of this study was to compare the effects of sandblasting on shear bond strength of three different metal brackets. Materials and Methods: For this experimental study, 180 human maxillary first and second premolars teeth were cleaned and stored in 0.1% thymol solution. The teeth were randomly assigned to either the control (n = 90 or experimental group (n = 90. Each group was subdivided into three equal groups (n = 30. In the control group, three different non-sandblasted metal brackets (American Orthodontics, Dentarum, and 3M Unitek were bonded with 3M (Unitek no-mix resin. In the next stage of the experiment, similar brackets were sandblasted and bonded. All samples were pumiced and etched with 37% phosphoric acid for 15 s. The teeth were embedded in blocks of autopolymerization polymethyl methacrylate, utilizing a special device to make their slots parallel to the horizontal. Samples were stored in distilled water for 24 h before testing. Shear bond testing was carried out with UTM Instron machine. Results: Mean shear bond strength of untreated groups was 15.51, 16.60, and 18.58 MPa for American Orthodontics, Dentarum, and 3M Unitek brackets, respectively. Mean shear bond strength of sandblasted brackets was 15.8, 19.36, and 18.66 for American Orthodontics, Dentarum, and 3M Unitek brackets, respectively. Conclusion: This study showed that there was a significant difference in the mean shear bond strength between untreated and sandblasted specimens only in the Dentarum bracket groups.

  16. Coordinating bracket torque and incisor inclination : Part 3: Validity of bracket torque values in achieving norm inclinations.

    Science.gov (United States)

    Zimmer, Bernd; Sino, Hiba

    2018-03-19

    To analyze common values of bracket torque (Andrews, Roth, MBT, Ricketts) for their validity in achieving incisor inclinations that are considered normal by different cephalometric standards. Using the equations developed in part 1 (eU1 (BOP) = 90° - BT (U1) - TCA (U1) + α 1 - α 2 and eL1 (BOP) = 90° - BT (L1) - TCA (L1) + β 1 - β 2 ) (abbreviations see part 1) and the mean values (± SD) obtained as statistical measures in parts 1 and 2 of the study (α 1 and β 1 [1.7° ± 0.7°], α 2 [3.6° ± 0.3°], β 2 [3.2° ± 0.4°], TCA (U1) [24.6° ± 3.6°] and TCA (L1) [22.9° ± 4.3°]) expected (= theoretically anticipated) values were calculated for upper and lower incisors (U1 and L1) and compared to targeted (= cephalometric norm) values. For U1, there was no overlapping between the ranges of expected and targeted values, as the lowest targeted value of (58.3°; Ricketts) was higher than the highest expected value (56.5°; Andrews) relative to the bisected occlusal plane (BOP). Thus all of these torque systems will aim for flatter inclinations than prescribed by any of the norm values. Depending on target values, the various bracket systems fell short by 1.8-5.5° (Andrews), 6.8-10.5° (Roth), 11.8-15.5° (MBT), or 16.8-20.5° (Ricketts). For L1, there was good agreement of the MBT system with the Ricketts and Björk target values (Δ0.1° and Δ-0.8°, respectively), and both the Roth and Ricketts systems came close to the Bergen target value (both Δ2.3°). Depending on target values, the ranges of deviation for L1 were 6.3-13.2° for Andrews (Class II prescription), 2.3°-9.2° for Roth, -3.7 to -3.2° for MBT, and 2.3-9.2° for Ricketts. Common values of upper incisor bracket torque do not have acceptable validity in achieving normal incisor inclinations. A careful selection of lower bracket torque may provide satisfactory matching with some of the targeted norm values.

  17. Conceptual design for PSP mounting bracket

    Energy Technology Data Exchange (ETDEWEB)

    Ransom, G.; Stein, R. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    Protective structural packages (PSP`s or overpacks) used to ship 2 1/2-ton UF{sub 6} product cylinders are bolted to truck trailers. All bolts penetrate two longitudinal rows of wooden planks. Removal and replacement is required at various intervals for maintenance and routine testing. A conceptual design is presented for mounting brackets which would securely attach PSP`s to trailer frames, reduce removal and replacement time, and minimize risk of personnel injury.

  18. Nambu brackets in fluid mechanics and magnetohydrodynamics

    International Nuclear Information System (INIS)

    Salazar, Roberto; Kurgansky, Michael V

    2010-01-01

    Concrete examples of the construction of Nambu brackets for equations of motion (both 3D and 2D) of Boussinesq stratified fluids and also for magnetohydrodynamical equations are given. It serves a generalization of Hamiltonian formulation for the considered equations of motion. Two alternative Nambu formulations are proposed, first by using fluid dynamical (kinetic) helicity and/or enstrophy as constitutive elements and second, by using the existing conservation laws of the governing equation.

  19. Comparison of shear bond strength of the stainless steel metallic brackets bonded by three bonding systems

    Directory of Open Access Journals (Sweden)

    Mehdi Ravadgar

    2013-09-01

    Full Text Available Introduction: In orthodontic treatment, it is essential to establish a satisfactory bond between enamel and bracket. After the self-etch primers (SEPs were introduced for the facilitation of bracket bonding in comparison to the conventional etch-and-bond system, multiple studies have been carried out on their shear bond strengths which have yielded different results. This study was aimed at comparing shear bond strengths of the stainless steel metallic brackets bonded by three bonding systems. Methods: In this experimental in vitro study, 60 extracted human maxillary premolar teeth were randomly divided into three equal groups: in the first group, Transbond XT (TBXT light cured composite was bonded with Transbond plus self-etching primer (TPSEP; in the second group, TBXT composite was bonded with the conventional method of acid etching; and in the third group, the self cured composite Unite TM bonding adhesive was bonded with the conventional method of acid etching. In all the groups, Standard edgewise-022 metallic brackets (American Orthodontics, Sheboygan, USA were used. Twenty-four hours after the completion of thermocycling, shear bond strength of brackets was measured by Universal Testing Machine (Zwick. In order to compare the shear bond strengths of the groups, the variance analysis test (ANOVA was adopted and p≤0.05 was considered as a significant level. Results: Based on megapascal, the average shear bond strength for the first, second, and third groups was 8.27±1.9, 9.78±2, and 8.92±2.5, respectively. There was no significant difference in the shear bond strength of the groups. Conclusions: Since TPSEP shear bond strength is approximately at the level of the conventional method of acid etching and within the desirable range for orthodontic brackets shear bond strength, applying TPSEP can serve as a substitute for the conventional method of etch and bond, particularly in orthodontic operations.

  20. Toothpaste prevents debonded brackets on erosive enamel.

    Science.gov (United States)

    Barros, Érico Luiz Damasceno; Pinto, Shelon Cristina Souza; Borges, Alvaro Henrique; Tonetto, Mateus Rodrigues; Ellwood, Roger Phillip; Pretty, Ian; Bandéca, Matheus Coelho

    2015-01-01

    This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 μg F(-)/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 μg F(-)/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. the high fluoride toothpaste prevents debonded brackets on erosive enamel.

  1. Toothpaste Prevents Debonded Brackets on Erosive Enamel

    Directory of Open Access Journals (Sweden)

    Érico Luiz Damasceno Barros

    2015-01-01

    Full Text Available This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n=12: WN (distilled water/no acid challenge, W3C (distilled water/3 cycles of acid challenge, and W6C (distilled water/6 cycles of acid challenge were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge and RF6C (regular fluoride dentifrice/6 cycles of acid challenge were treated with dentifrices containing 1450 μg F−/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge and HF6C (high fluoride dentifrice/6 cycles of acid challenge were with 5000 μg F−/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P>0.05. Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05. Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. Clinical relevance: the high fluoride toothpaste prevents debonded brackets on erosive enamel.

  2. Fractional Dirac bracket on Riemman-Liouville context

    Energy Technology Data Exchange (ETDEWEB)

    Godinho, Cresus F.L.; Abreu, Everton M.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

    2011-07-01

    Full text: So far, it is not well known how to deal with dissipative systems. There are many ways explored in the literature and none of them present a systematic and general procedure to tackle the problem. On the other hand, it is well known that the fractional formalism is a powerful alternative when treating dissipative problems. In this paper we propose a detailed way of attacking the issue using the fractional calculus to construct an extension for the Dirac brackets in order to furnish the quantization of nonconservative theories through the standard canonical way. We believe that it can be the first step to construct gauge theories from second-class systems using these extended Dirac brackets. Very popular in the nineties, where an industrial production of papers concerning methods treating constrained systems, the Dirac brackets (DB) were an unmodified common point between all papers in the subject. The main objective of many works were to convert second-class systems in a first-class one, which is considered a gauge theory, i. e., the holy grail for the Standard Model. Although not so popular as before, the analysis of constrained systems deserves some recent attentions in the literature. On the other hand, there are various problems when considering classical systems besides the ones involving the quantization of second-class systems as we saw just above. These problems constitutes the so-called nonconservative systems. The curiosity about them is that the great majority of classical systems is nonconservative and nevertheless, the most advanced formalisms of classical mechanics deals only with conservative systems. One way to attack nonconservative systems is through the Fractional Calculus (FC) since it can be shown that, for example, a friction force has its form resulting from a Lagrangian containing a term proportional to the fractional derivative which is a derivative of any non-integer order. Fractional calculus is one of the generalizations of

  3. Technology and Technique Standards for Camera-Acquired Digital Dermatologic Images: A Systematic Review.

    Science.gov (United States)

    Quigley, Elizabeth A; Tokay, Barbara A; Jewell, Sarah T; Marchetti, Michael A; Halpern, Allan C

    2015-08-01

    Photographs are invaluable dermatologic diagnostic, management, research, teaching, and documentation tools. Digital Imaging and Communications in Medicine (DICOM) standards exist for many types of digital medical images, but there are no DICOM standards for camera-acquired dermatologic images to date. To identify and describe existing or proposed technology and technique standards for camera-acquired dermatologic images in the scientific literature. Systematic searches of the PubMed, EMBASE, and Cochrane databases were performed in January 2013 using photography and digital imaging, standardization, and medical specialty and medical illustration search terms and augmented by a gray literature search of 14 websites using Google. Two reviewers independently screened titles of 7371 unique publications, followed by 3 sequential full-text reviews, leading to the selection of 49 publications with the most recent (1985-2013) or detailed description of technology or technique standards related to the acquisition or use of images of skin disease (or related conditions). No universally accepted existing technology or technique standards for camera-based digital images in dermatology were identified. Recommendations are summarized for technology imaging standards, including spatial resolution, color resolution, reproduction (magnification) ratios, postacquisition image processing, color calibration, compression, output, archiving and storage, and security during storage and transmission. Recommendations are also summarized for technique imaging standards, including environmental conditions (lighting, background, and camera position), patient pose and standard view sets, and patient consent, privacy, and confidentiality. Proposed standards for specific-use cases in total body photography, teledermatology, and dermoscopy are described. The literature is replete with descriptions of obtaining photographs of skin disease, but universal imaging standards have not been developed

  4. Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

    Directory of Open Access Journals (Sweden)

    Rogerio Amaral Tupinambá

    Full Text Available ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO polymer films were deposited on conventional (n = 10 and self-ligating (n = 10 stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p 0.05. Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

  5. Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

    Science.gov (United States)

    Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

    2017-01-01

    ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film. PMID:28902253

  6. Assessment of bracket surface morphology and dimensional change

    Directory of Open Access Journals (Sweden)

    Pillai Devu Radhakrishnan

    2017-01-01

    Full Text Available Objective: The objective of this study was to compare the surface morphology and dimensional stability of the bracket slot at the onset of treatment and after 12 months of intraoral exposure. The study also compared the amount of calcium at the bracket base which indicates enamel loss among the three orthodontic brackets following debonding after 12 months of intraoral exposure. Materials and Methods: The sample consisted of 60 (0.022” MBT canine brackets. They were divided into three groups: self-ligating, ceramic bracket with metal slot, and stainless steel (SS brackets. The slot dimensions, micromorphologic characteristics of as-received and retrieved brackets were measured with a stereomicroscope and scanning electron microscope (SEM, respectively. The amount of calcium at the bracket base which indicates enamel damage was quantified using energy-dispersive X-ray spectrometry (EDX. Results: The results showed statistically significant alterations (P < 0.05 in the right vertical dimension, internal tie wing width (cervical, right and left depth of the slot (Kruskal–Wallis test. Multiple comparison using Mann–Whitney test showed that ceramic brackets underwent (P < 0.05 minimal alterations in the right vertical dimension, internal tie wing width (cervical, right and left depth of the slot (0.01 mm, −0.003 mm, 0.006 mm, −0.002 mm, respectively when compared with the changes seen in SS and self-ligating brackets. SEM analysis revealed an increase in the surface roughness of ceramic with metal slot brackets and self-ligating bracket showed the least irregularity. The presence of calcium was noted on all evaluated brackets under EDX, but ceramic with metal slot brackets showed a significantly greater amount of enamel loss (P = 0.001. Conclusion: Ceramic brackets were found to be dimensionally stable when compared to SS and self-ligating. Self-ligating bracket showed minimal surface irregularity. Ceramic with metal slot brackets showed a

  7. A comparative assessment of torque generated by lingual and conventional brackets

    NARCIS (Netherlands)

    Sifakakis, I.; Pandis, N.; Makou, M.; Eliades, T.; Katsaros, C.; Bourauel, C.

    2013-01-01

    The aim of this study was to assess the effect of bracket type on the labiopalatal moments generated by lingual and conventional brackets. Incognito lingual brackets (3M Unitek), STb lingual brackets (Light Lingual System; ORMCO), In-Ovation L lingual brackets (DENTSPLY GAC), and conventional 0.018

  8. Beatification: Flattening Poisson brackets for plasma theory and computation

    Science.gov (United States)

    Morrison, P. J.; Viscondi, T. F.; Caldas, I.

    2017-10-01

    A perturbative method called beatification is presented for producing nonlinear Hamiltonian fluid and plasma theories. Plasma Hamiltonian theories, fluid and kinetic, are naturally described in terms of noncanonical variables. The beatification procedure amounts to finding a transformation that removes the explicit variable dependence from a noncanonical Poisson bracket and replaces it with a fixed dependence on a chosen state in the phase space. As such, beatification is a major step toward casting the Hamiltonian system in its canonical form, thus enabling or facilitating the use of analytical and numerical techniques that require or favor a representation in terms of canonical, or beatified, Hamiltonian variables. Examples will be given. U.S. D.O.E No. #DE-FG02-04ER-54742.

  9. Experimental study of some mounting brackets to support fuel elements

    International Nuclear Information System (INIS)

    Aubert, M.; Poglia, S.; Roche, R.

    1958-09-01

    In an atomic pile with vertical channels, fuel elements are stacked on one another. According to a possible assembly, fuel element can be contained by a graphite sleeve and be supported by a mounting bracket in this sleeve. Sleeves are then stacked on one another. The authors report the investigation of different designs for these mounting brackets. They describe their mechanical role and their mechanical, aerodynamic, neutronic and test conditions. They report tests performed on brackets made in graphite and on brackets made in stainless steel and graphite, and discuss the obtained results

  10. Maxillary arch width and buccal corridor changes with Damon and conventional brackets: A retrospective analysis.

    Science.gov (United States)

    Shook, Corey; Kim, Sohyon Michelle; Burnheimer, John

    2016-07-01

    To evaluate the effect of Damon self-ligating and conventional bracket systems on buccal corridor widths and areas. A retrospective sample of consecutively treated patients using either conventional (CG, n  =  45) or Damon self-ligating (SL, n  =  39) brackets was analyzed to determine any differences in buccal corridor widths and areas both within and between groups. Pretreatment and posttreatment frontal photographs were transferred to Photoshop CC, standardized using intercanthal width, and linear and area measurements were performed with tools in Photoshop CC. Ratios were then calculated for statistical analysis. Relationships between arch widths and buccal corridors were also examined. There were no significant differences in the posttreatment intercanine or intermolar widths either within or between the CG and SL groups. There were no significant differences in any buccal corridor width or area measurement either within or between the CG and SL groups. There were strong correlations with the intercanine width and the corresponding buccal corridor smile width measurements. There was an inverse correlation with the buccal corridor area in relation to the canine and the total smile width. It is likely that posttreatment increases in arch width can be seen in patients treated with either a conventional bracket system or the Damon system. It is highly unlikely that there is any significant difference in buccal corridor width or area in patients treated with the Damon self-ligating system or a conventional bracket system.

  11. Static and kinetic friction force and surface roughness of different archwire-bracket sliding contacts.

    Science.gov (United States)

    Carrion-Vilches, Francisco J; Bermudez, María-Dolores; Fructuoso, Paula

    2015-01-01

    The aim of this study was to determine the static and kinetic friction forces of the contact bracket-archwire with different dental material compositions in order to select those materials with lower resistance to sliding. We carried out sliding friction tests by means of a universal testing machine following an experimental procedure as described in ASTM D1894 standard. We determined the static and kinetic friction forces under dry and lubricating conditions using an artificial saliva solution at 36.5ºC. The bracket-archwire pairs studied were: stainless steel-stainless steel; stainless steel-glass fiber composite; stainless steel-Nitinol 60; sapphire-stainless steel; sapphire-glass fiber composite; and sapphire-Nitinol 60. The best performance is obtained for Nitinol 60 archwire sliding against a stainless steel bracket, both under dry and lubricated conditions. These results are in agreement with the low surface roughness of Nitinol 60 with respect to the glass fiber composite archwire. The results described here contribute to establishing selection criteria for materials for dental archwire-brackets.

  12. Shear bond strength of self-ligating orthodontic brackets on different types of porcelain crowns

    Directory of Open Access Journals (Sweden)

    Karamdeep Singh Ahluwalia

    2013-01-01

    Full Text Available Aim: The aim of this study is to compare shear bond strength (SBS and adhesive remnant index (ARI of self-ligating orthodontic brackets bonded to different porcelain crowns. Materials and Methods: Three groups of different types of porcelain crowns, each containing 12 crowns were fabricated by the same technician and allocated to one of the study groups as follows: Group I - IPS porcelain crowns (Ivoclar Vivadent AG, Schaan, Liechtenstein, Group II - Porcelain fused to zirconia crowns (Zirkonzahn GmbH, Gais, Italy, Noritake Co., Tokyo, Japan and Group III - Conventional porcelain fused to metal crowns (Ceramco3, Densply, PA, USA. The orthodontic brackets were bonded to these crowns using hydrofluoric acid (HFA + silane etching protocol. After bonding, the SBS of the brackets were tested with a universal testing machine under standard test conditions. Results: Statistical evaluation using analysis of variance showed a significant difference between the groups (P 0.05. Chi-square comparison revealed no significant difference in ARI scores between groups (P > 0.05. Conclusions: When HFA + silane etching protocol were used, IPS crowns showed the greatest SBS of orthodontic brackets. The ARI score was non-significant. Therefore, if there is a need to place crowns over teeth then these crowns can be used for restoration of teeth before orthodontic treatment.

  13. Evaluation of friction of stainless steel and esthetic self-ligating brackets in various bracket-archwire combinations.

    Science.gov (United States)

    Cacciafesta, Vittorio; Sfondrini, Maria Francesca; Ricciardi, Andrea; Scribante, Andrea; Klersy, Catherine; Auricchio, Ferdinando

    2003-10-01

    This study measured and compared the level of frictional resistance generated between stainless steel self-ligating brackets (Damon SL II, SDS Ormco, Glendora, Calif), polycarbonate self-ligating brackets (Oyster, Gestenco International, Göthenburg, Sweden), and conventional stainless steel brackets (Victory Series, 3M Unitek, Monrovia, Calif), and 3 different orthodontic wire alloys: stainless steel (Stainless Steel, SDS Ormco), nickel-titanium (Ni-Ti, SDS Ormco), and beta-titanium (TMA, SDS Ormco). All brackets had a.022-in slot, whereas the orthodontic wire alloys were tested in 3 different sections:.016,.017 x.025, and.019 x 0.025 in. Each of the 27 bracket and archwire combinations was tested 10 times, and each test was performed with a new bracket-wire sample. Both static and kinetic friction were measured on a custom-designed apparatus. All data were statistically analyzed (Kruskal-Wallis and Mann Whitney U tests). Stainless steel self-ligating brackets generated significantly lower static and kinetic frictional forces than both conventional stainless steel and polycarbonate self-ligating brackets, which showed no significant differences between them. Beta-titanium archwires had higher frictional resistances than stainless steel and nickel-titanium archwires. No significant differences were found between stainless steel and nickel-titanium archwires. All brackets showed higher static and kinetic frictional forces as the wire size increased.

  14. Evaluation of frictional forces of polycarbonate self-ligating brackets.

    Science.gov (United States)

    Fernandes, Daniel J; Miguel, José Augusto M; Quintão, Catia C A; Elias, Carlos N

    2010-01-01

    To evaluate the frictional forces generated by ceramic- (Opal, Ultradent) and glass-fiber-reinforced polycarbonate self-ligating brackets (Oyster, Gestenco) and compare the effectiveness of these ligatureless systems with glass-fiber-reinforced polycarbonate conventional brackets (Blonde, Gestenco). The hypothesis is that there is no difference between frictional forces generated by ceramic- and glass-fiber-reinforced polycarbonate self-ligating and glass-fiber-reinforced polycarbonate conventional brackets. Twelve preadjusted 0.022 3 0.028-inch maxillary canine brackets were tested, divided into three groups: Opal, Oyster, and Blonde. Frictional tests were conducted with the Emic DL 10000 testing machine with a 20 N loadcell for 40 seconds at a 0.5 cm/min speed. Each bracket-wire combination was tested five times. The data generated were analyzed by parametric analysis of variance (one-way ANOVA) and Bonferroni tests. Analysis of variance indicated significant differences for the three groups (Pfrictional forces of the Oyster glass-fiber-reinforced polycarbonate self-ligating brackets were significantly lower (37.0 ± 8.9 cN) than those of the Opal ceramic-reinforced polycarbonate self-ligating brackets (49.5 ± 10.1 cN), while the Blonde glass-fiber-reinforced conventional bracket frictional forces were 105.8 ± 6.4 cN. Oyster glass-fiber-reinforced polycarbonate brackets produced less friction than Opal ceramic-reinforced polycarbonate brackets. The polycarbonate ligatureless system showed significantly lower frictional forces compared to Blonde conventional polycarbonate brackets tied with elastomeric ligatures. The study rejected the initial hypothesis because there are significant differences of frictional forces among the tested systems. © 2010 BY QUINTESSENCE PUBLISHING CO, INC.

  15. Bonding brackets to porcelain: in vitro study

    Directory of Open Access Journals (Sweden)

    Sant'Anna Eduardo Franzotti

    2002-01-01

    Full Text Available The aim of this research was to verify, in vitro, the effect of various porcelain surface treatments on the shear strength of orthodontic brackets bonded to porcelain and the mode of fracture after debonding. Eighty-eight samples of metallic supported feldspathic porcelain were randomly divided into four groups according to their surface preparation as follows: the porcelain was maintained intact (GI, roughened with a diamond bur (GII, etched with 10% hydrofluoric acid (GIII, or sandblasted with aluminum oxide (GIV. The specimens were treated with silane (Scothprime and brackets were bonded with Concise. Each sample was subjected to a shear load at a crosshead speed of 1 mm/min and a recording was made at the point of failure. Bond strengths, adequate to withstand the application of orthodontic forces, were achieved in all groups. The Kruskal-Wallis statistical test showed no significant differences in bond strength between the groups (p>0.05. However, many more porcelain fractures occurred on deglazed porcelain. This study indicates that with the appropriate material selection, the silane/composite procedure alone may be adequate for bonding.

  16. Formulation of Hamiltonian mechanics with even and odd Poisson brackets

    International Nuclear Information System (INIS)

    Khudaverdyan, O.M.; Nersesyan, A.P.

    1987-01-01

    A possibility is studied as to constrict the odd Poisson bracket and odd Hamiltonian by the given dynamics in phase superspace - the even Poisson bracket and even Hamiltonian so the transition to the new structure does not change the equations of motion. 9 refs

  17. 3D-printed orthodontic brackets - proof of concept.

    Science.gov (United States)

    Krey, Karl-Friedrich; Darkazanly, Nawras; Kühnert, Rolf; Ruge, Sebastian

    Today, orthodontic treatment with fixed appliances is usually carried out using preprogrammed straight-wire brackets made of metal or ceramics. The goal of this study was to determine the possibility of clinically implementing a fully digital workflow with individually designed and three-dimensionally printed (3D-printed) brackets. Edgewise brackets were designed using computer-aided design (CAD) software for demonstration purposes. After segmentation of the malocclusion model generated based on intraoral scan data, the brackets were digitally positioned on the teeth and a target occlusion model created. The thus-defined tooth position was used to generate a template for an individualized arch form in the horizontal plane. The base contours of the brackets were modified to match the shape of the tooth surfaces, and a positioning guide (fabricated beforehand) was used to ensure that the brackets were bonded at the correct angle and position. The brackets, positioning guide, and retainer splint, digitally designed on the target occlusion model, were 3D printed using a Digital Light Processing (DLP) 3D printer. The archwires were individually pre-bent using the template. In the treatment sequence, it was shown for the first time that, in principle, it is possible to perform treatment with an individualized 3D-printed brackets system by using the proposed fully digital workflow. Technical aspects of the system, problems encountered in treatment, and possible future developments are discussed in this article.

  18. Comparison of canine retraction using single and Siamese edgewise brackets: An in vivo study

    Directory of Open Access Journals (Sweden)

    Zeeshan Iqbal Bhat

    2013-01-01

    Full Text Available Objectives: The purpose of this study was to check the rate of canine retraction with bodily mechanics using two different pre-adjusted edgewise bracket Systems. Materials and Methods: A split mouth study with twenty patients who were randomly selected and allotted to a single operator. Duration of canine retraction, angulation of canine during its retraction, degree of Rotation, anchorage Loss, distance between canine and premolar at different time intervals were then evaluated, pre- (To, 3 months- (T1 and canine tip touches the second premolar- (T2. Descriptive statistics including mean values and standard deviations were calculated. Paired and unpaired t-test was performed to evaluate the differences between the groups. Results: Rotation and angulation of the canines did not show significant difference in both the systems. There was statistically significant difference (P<0.01 in anchorage loss between single wing and Siamese bracket being 2.65 ±1.41 mm and 1.31 ± 0.93 respectively. There was statistically significant intergroup difference (P<0.01 in canine movement i.e distance between canine and premolar was recorded as 4.72mm (15.06 ± 1.69 to 10.34 ± 1.68mm in single wing bracket and 6.25mm in Siamese (15.52 ± 1.41 to 9.27 ± 1.94. Conclusion: In cases where high anchorage is required and the rate of canine retraction is a concern, Siamese brackets pose a definite advantage over Single wing brackets.

  19. Real-time cell analysis of the cytotoxicity of orthodontic brackets on gingival fibroblasts.

    Science.gov (United States)

    Toy, Ebubekir; Malkoc, Siddik; Corekci, Bayram; Bozkurt, Buket S; Hakki, Sema S

    2014-12-30

    The aim of this study was to evaluate the cytotoxic effects of 6 different orthodontic bracket types on human gingival fibroblasts (HGFs) using the xCELLigence system.
 The orthodontic brackets used in this study were gold-plated steel (Apollo Gold), titanium (Rematitan), stainless steel (Equilibrium 2), lucid ice (Inspire ICE), metal-reinforced ceramic (Clarity) and composite (OrthoFlex). Gingival fibroblasts were isolated from human gingival connective tissue of systemically healthy individuals. Tested brackets were incubated in DMEM culture medium for 72 hours according to ISO 10993-5 standards. Gingival fibroblasts were maintained with Dulbecco modified Eagle medium containing 10% fetal bovine serum. The xCELLigence system was used to evaluate cell survival. The statistical analysis used was ANOVA and Tukey-Kramer multiple comparison tests.
 When the data were evaluated in the 30th hour, Apollo Gold showed significant decreases in cell index (P<0.001). It also showed statistically significant decreases (P<0.001) in the 65th hour, but Clarity and Inspire ICE showed significant increases in cell indices (P<0.001, P<0.01). In the 114th hour, Clarity and Equilibrium 2 showed statistically significant increases in cell indices (P<0.001). Inspire ICE and Rematitan demonstrated significant increases (P<0.05). There were significant decreases in cell index of Apollo Gold (P<0.001). 
 The tested brackets are suitable for clinical application, but further studies using different test methods are needed for gold-plated brackets.

  20. Comparative efficacy of Er,Cr:YSGG and Er:YAG lasers for etching of composite for orthodontic bracket bonding.

    Science.gov (United States)

    Mirhashemi, Amir Hossein; Chiniforush, Nasim; Sharifi, Nastaran; Hosseini, Amir Mehdi

    2018-01-11

    Several techniques have been proposed to obtain a durable bond, and the efficacy of these techniques is assessed by measuring parameters such as bond strength. Laser has provided a bond strength as high as that of acid etching in vitro and has simpler use with shorter clinical time compared to acid etching. This study aimed to compare the efficacy of Er:YAG and Er,Cr:YSGG lasers for etching and bonding of composite to orthodontic brackets. No previous study has evaluated the effect of these particular types of laser. A total of 70 composite blocks were randomly divided into five groups (n = 14): group 1, etching with phosphoric acid for 20 s; group 2, Er:YAG laser irradiation with 2 W power for 10 s; group 3, Er:YAG laser with 3 W power for 10 s; group 4, Er,Cr:YSGG laser with 2 W power for 10 s; group 5, Er,Cr:YSGG laser with 3 W power for 10 s. Metal brackets were then bonded to composites, and after 5000 thermal cycles, they were subjected to shear bond strength test in a universal testing machine after 24 h of water storage. One sample of each group was evaluated under a scanning electron microscope (SEM) to assess changes in composite surface after etching. The adhesive remnant index (ARI) was calculated under a stereomicroscope. Data were statistically analyzed. The mean and standard deviation of shear bond strength were 18.65 ± 3.36, 19.68 ± 5.34, 21.31 ± 4.03, 17.38 ± 6.94, and 16.45 ± 4.26 MPa in groups 1-5, respectively. The ARI scores showed that the bond failure mode in all groups was mainly mixed. The groups were not significantly different in terms of shear bond strength. Er:YAG and Er,Cr:YSGG lasers with the mentioned parameters yield optimal shear bond strength and can be used as an alternative to acid etching for bracket bond to composite.

  1. Standardization of proton-induced x-ray emission technique for analysis of thick samples

    Science.gov (United States)

    Ali, Shad; Zeb, Johar; Ahad, Abdul; Ahmad, Ishfaq; Haneef, M.; Akbar, Jehan

    2015-09-01

    This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

  2. A comparison between two lateral cephalometry techniques (standard and natural head position

    Directory of Open Access Journals (Sweden)

    Hedayati Z. Assistant Professor. Sang S. DMD

    2003-06-01

    Full Text Available Statement of Problem: Cephalometric findings are of high importance in making decision about orthodontic treatment plans and orthognathic surgeries. Natural head position (NHP is considered as a useful and exact radiographic technique."nAim: The aim of the present study was to compare two techniques, namely Standard and NHP, in lateral"ncephalometry."nMaterials and Methods: In this cross- sectional study, performed in Shiraz. 138 randomly selected students {70 males .and 68 females, age ranging from (13-15. were evaluated clinically and radiographically. None of them had a history of orthodontic treatment, head and face fracture or surgical operations. Lateral cephalograms were taken in both standard and natural head position techniques, for each student. For statistical analysis, l-lest for paired samples, was done."nResults: This study showed that in anterior-posterior dimension, among angles with significant differences in two techniques, those of standard one were more reliable, whereas in vertical dimension."nstatistical differences showed natural technique as more useful one."nConclusion: Due to the fact that natural cephalometry requires more patient cooperation, more time and a higher complex technique, it is not suggested, except when different clinical and cepholomeiric findings are observed.

  3. Laryngeal mask airway insertion in children: comparison between rotational, lateral and standard technique.

    Science.gov (United States)

    Ghai, Babita; Makkar, Jeetinder Kaur; Bhardwaj, Neerja; Wig, Jyotsna

    2008-04-01

    The purpose of the study was to compare the success and ease of insertion of three techniques of laryngeal mask airway (LMA) insertion; the standard Brain technique, a lateral technique with cuff partially inflated and a rotational technique with cuff partially inflated. One hundred and sixty-eight ASA I and II children aged 6 months to 6 years undergoing short elective surgical procedures lasting 40-60 min were included in the study. A standard anesthesia protocol was followed for all patients. Patients were randomly allocated into one of the three groups i.e. standard (S), rotational (R) and lateral (L). The primary outcome measure of the study was success rate at the first attempt using three techniques of LMA insertion. Secondary outcomes measures studied were overall success rate, time before successful LMA insertion, complications and maneuvers used to relieve airway obstruction. Successful insertion at the first attempt was significantly higher in group R (96%) compared with group L (84%) and group S (80%) (P = 0.03). Overall success rate (i.e. successful insertion with two attempts) was 100% for group R, 93% for group L and 87% for group S (P = 0.03). Time for successful insertion was significantly lower in group R compared with group L and S (P insertion and lowest incidence of complications and could be the technique of first choice for LMA insertion in pediatric patients.

  4. Effects of 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets on Shear Bond Strength.

    Science.gov (United States)

    Stein, Steffen; Hellak, Andreas; Schauseil, Michael; Korbmacher-Steiner, Heike; Braun, Andreas

    2018-01-01

    The aim of this study was to measure the effect of irradiation with a novel 445-nm diode laser on the shear bond strength (SBS) of ceramic brackets before debonding. Thirty ceramic brackets (In-Ovation ® C, GAC) were bonded in standard manner to the planed and polished buccal enamel surfaces of 30 caries-free human third molars. Each tooth was randomly allocated to the laser or control group, with 15 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue ® ; Sirona) on three sides of the bracket bases for 5 sec each (lateral-coronal-lateral, a total of 15 sec) immediately before debonding. SBS values were measured for the laser group and control group. To assess the adhesive remnant index (ARI) and the degree of enamel fractures, micrographs of the enamel surface were taken with 10-fold magnification after debonding. The SBS values were significantly lower statistically in the laser group in comparison with the control group (p diode laser before debonding significantly reduces the SBS values. This is of clinical importance, as it means that the risk of damage to the teeth, bracket fractures, and the overall treatment time can be reduced.

  5. Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: A pilot study

    Directory of Open Access Journals (Sweden)

    Guilherme Caiado Sobral

    2014-10-01

    Full Text Available OBJECTIVE: By means of a photoelastic model, this study analyzed the stress caused on conventional and self-ligating brackets with expanded arch wires. METHOD: Standard brackets were adhered to artificial teeth and a photoelastic model was prepared using the Interlandi 19/12 diagram as base. Successive activations were made with 0.014-in and 0.018-in rounded cross section Nickel-Titanium wires (NiTi and 0.019 x 0.025-in rectangular stainless steel wires all of which made on 22/14 Interlandi diagram. The model was observed on a plane polariscope - in a dark field microscope configuration - and photographed at each exchange of wire. Then, they were replaced by self-ligating brackets and the process was repeated. Analysis was qualitative and observed stress location and pattern on both models analyzed. CONCLUSIONS: Results identified greater stress on the region of the apex of premolars in both analyzed models. Upon comparing the stress between models, a greater amount of stress was found in the model with conventional brackets in all of its wires. Therefore, the present pilot study revealed that alignment of wires in self-ligating brackets produced lower stress in periodontal tissues in expansive mechanics.

  6. Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: a pilot study.

    Science.gov (United States)

    Sobral, Guilherme Caiado; Vedovello Filho, Mário; Degan, Viviane Veroni; Santamaria, Milton

    2014-01-01

    By means of a photoelastic model, this study analyzed the stress caused on conventional and self-ligating brackets with expanded arch wires. Standard brackets were adhered to artificial teeth and a photoelastic model was prepared using the Interlandi 19/12 diagram as base. Successive activations were made with 0.014-in and 0.018-in rounded cross section Nickel-Titanium wires (NiTi) and 0.019 x 0.025-in rectangular stainless steel wires all of which made on 22/14 Interlandi diagram. The model was observed on a plane polariscope--in a dark field microscope configuration--and photographed at each exchange of wire. Then, they were replaced by self-ligating brackets and the process was repeated. Analysis was qualitative and observed stress location and pattern on both models analyzed. Results identified greater stress on the region of the apex of premolars in both analyzed models. Upon comparing the stress between models, a greater amount of stress was found in the model with conventional brackets in all of its wires. Therefore, the present pilot study revealed that alignment of wires in self-ligating brackets produced lower stress in periodontal tissues in expansive mechanics.

  7. Development of Superhydrophobic Material SS 17-4 PH for Bracket Orthodontic Application by Metal Injection Molding

    Science.gov (United States)

    Supriadi, S.; Suharno, B.; Widjaya, T.; Ayuningtyas, S. T.; Baek, E. R.

    2018-01-01

    Dental’s plaque is a common problem that encountered during orthodontic treatment using bracket. It is caused by demineralization of enamel due to the activity of bacteria. The bacteria increase with remaining excess food which trapped in teeth and bracket. A hydrophobic surface could reduce food attachment on the bracket because of extremely low wettability properties that make it easy to clean with water. There are several methods to obtain hydrophobic surfaces, which are sol-gel, template replica and also etching. The propose of this work is to compare etching treatment and surface modification on sintered SS 17-4 PH as bracket material using CuCl2 and HCl as an etchant while stearic acid was used for surface modification. Hydrophobic surfaces were produced under various etching time i.e 15, 30, 45 and 60 seconds for CuCl2 and 40, 50, 60 and 70 minutes for HCl and also HCl concentration i.e 1,2 and 3 mol/L at room temperature. The hydrophobicity is observed using contact angle measurement while the microstructures observed by Scanning Electron Microscope. The result shows the contact angle could be achieved up to 60% higher than the as-sintered material. Hydrophobic structure has successfully fabricated using etching technique that might be applied to the orthodontic bracket.

  8. Standard techniques for presentation and analysis of crater size-frequency data

    Science.gov (United States)

    1978-01-01

    In September 1977, a crater studies workshop was held for the purpose of developing standard data analysis and presentation techniques. This report contains the unanimous recommendations of the participants. This first meeting considered primarily crater size-frequency data. Future meetings will treat other aspects of crater studies such as morphologies.

  9. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Kyung Soo; Kim, Ae Ji [Dept. of Oral Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Doh, Shi Hong [Dept. of Applied physics . National Fisheries University of Pusan Department of Radiotherapy, Pusan (Korea, Republic of); Kim, Hyun Ja [Dept. of Oral Radiology, Baptist Hospital, Pusan (Korea, Republic of); Yoo, Meong Jin [Dept. of Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    1990-08-15

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  10. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    International Nuclear Information System (INIS)

    Nah, Kyung Soo; Kim, Ae Ji; Doh, Shi Hong; Kim, Hyun Ja; Yoo, Meong Jin

    1990-01-01

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  11. Color stability of ceramic brackets immersed in potentially staining solutions

    Directory of Open Access Journals (Sweden)

    Bruna Coser Guignone

    2015-08-01

    Full Text Available OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18 according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva. The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA, Radiance (American Orthodontics, Sheboygan, WI, USA, Mystique (GAC International Inc., Bohemia, NY, USA and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA. Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0, 24 hours (T1, 72 hours (T2, as well as 7 days (T3 and 14 days (T4 of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

  12. Elemental analyses of goundwater: demonstrated advantage of low-flow sampling and trace-metal clean techniques over standard techniques

    Science.gov (United States)

    Creasey, C. L.; Flegal, A. R.

    The combined use of both (1) low-flow purging and sampling and (2) trace-metal clean techniques provides more representative measurements of trace-element concentrations in groundwater than results derived with standard techniques. The use of low-flow purging and sampling provides relatively undisturbed groundwater samples that are more representative of in situ conditions, and the use of trace-element clean techniques limits the inadvertent introduction of contaminants during sampling, storage, and analysis. When these techniques are applied, resultant trace-element concentrations are likely to be markedly lower than results based on standard sampling techniques. In a comparison of data derived from contaminated and control groundwater wells at a site in California, USA, trace-element concentrations from this study were 2-1000 times lower than those determined by the conventional techniques used in sampling of the same wells prior to (5months) and subsequent to (1month) the collections for this study. Specifically, the cadmium and chromium concentrations derived using standard sampling techniques exceed the California Maximum Contaminant Levels (MCL), whereas in this investigation concentrations of both of those elements are substantially below their MCLs. Consequently, the combined use of low-flow and trace-metal clean techniques may preclude erroneous reports of trace-element contamination in groundwater. Résumé L'utilisation simultanée de la purge et de l'échantillonnage à faible débit et des techniques sans traces de métaux permet d'obtenir des mesures de concentrations en éléments en traces dans les eaux souterraines plus représentatives que les résultats fournis par les techniques classiques. L'utilisation de la purge et de l'échantillonnage à faible débit donne des échantillons d'eau souterraine relativement peu perturbés qui sont plus représentatifs des conditions in situ, et le recours aux techniques sans éléments en traces limite l

  13. Standardization of the Descemet membrane endothelial keratoplasty technique: Outcomes of the first 450 consecutive cases.

    Science.gov (United States)

    Satué, M; Rodríguez-Calvo-de-Mora, M; Naveiras, M; Cabrerizo, J; Dapena, I; Melles, G R J

    2015-08-01

    To evaluate the clinical outcome of the first 450 consecutive cases after Descemet membrane endothelial keratoplasty (DMEK), as well as the effect of standardization of the technique. Comparison between 3 groups: Group I: (cases 1-125), as the extended learning curve; Group II: (cases 126-250), transition to technique standardization; Group III: (cases 251-450), surgery with standardized technique. Best corrected visual acuity, endothelial cell density, pachymetry and intra- and postoperative complications were evaluated before, and 1, 3 and 6 months after DMEK. At 6 months after surgery, 79% of eyes reached a best corrected visual acuity of≥0.8 and 43%≥1.0. Mean preoperative endothelial cell density was 2,530±220 cells/mm2 and 1,613±495 at 6 months after surgery. Mean pachymetry measured 668±92 μm and 526±46 μm pre- and (6 months) postoperatively, respectively. There were no significant differences in best corrected visual acuity, endothelial cell density and pachymetry between the 3 groups (P > .05). Graft detachment presented in 17.3% of the eyes. The detachment rate declined from 24% to 12%, and the rate of secondary surgeries from 9.6% to 3.5%, from group I to III respectively. Visual outcomes and endothelial cell density after DMEK are independent of the technique standardization. However, technique standardization may have contributed to a lower graft detachment rate and a relatively low number of secondary interventions required. As such, DMEK may become the first choice of treatment in corneal endothelial disease. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  14. Mellin-Barnes meets Method of Brackets: a novel approach to Mellin-Barnes representations of Feynman integrals

    Energy Technology Data Exchange (ETDEWEB)

    Prausa, Mario [RWTH Aachen University, Institute for Theoretical Particle Physics and Cosmology, Aachen (Germany)

    2017-09-15

    In this paper, we present a new approach to the construction of Mellin-Barnes representations for Feynman integrals inspired by the Method of Brackets. The novel technique is helpful to lower the dimensionality of Mellin-Barnes representations in complicated cases, some examples are given. (orig.)

  15. Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

    Directory of Open Access Journals (Sweden)

    C A Abdul Shahariyar

    2016-01-01

    Full Text Available Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs and conventional means respectively. These were further equally divided into three subgroups - (1 control (2 CPP-ACP (3 chlorhexidine fluoride mouthwash. The SBSs were then measured using a universal testing machine. Results: SBS of the conventional group was significantly higher than the self-etching group. The intragroup differences were statistically insignificant. Conclusion: CPP-ACP, chlorhexidine fluoride mouthwash did not adversely affect SBS of orthodontic brackets irrespective of the method of conditioning. Brackets bonded with conventional technique showed greater bond strengths as compared to those bonded with SEP.

  16. A comparative assessment of forces and moments generated by lingual and conventional brackets

    NARCIS (Netherlands)

    Sifakakis, I.; Pandis, N.; Makou, M.; Katsaros, C.; Eliades, T.; Bourauel, C.

    2013-01-01

    The aim of this study was to assess the effect of bracket type on the labiopalatal forces and moments generated in the sagittal plane. Incognito lingual brackets (3M Unitek), STb lingual brackets (Light Lingual System; ORMCO), and conventional 0.018 inch slot brackets (Gemini; 3M Unitek) were bonded

  17. A survey on development of neutron standards and neutron measurement technique corresponding to various fields

    International Nuclear Information System (INIS)

    Matsumoto, Tetsuro

    2007-01-01

    Various uses of neutrons are being watched in many fields such as industry, medical technology and radiation protection. Especially, high energy neutrons above 15 MeV are important in a radiation exposure issue of an aircraft and a soft error issue of a semiconductor. Therefore neutron fluence standards for the high energy region are very important. However, the standards are not almost provided all over the world. Three reasons are mainly considered: (1) poor measurement techniques for the high energy neutrons, (2) a small number of high energy neutron facilities and (3) lack of nuclear data for high energy particle reactions. In this paper, the present status of the measurement techniques, the facilities and the nuclear data is investigated and discussed. In NMIJ/AIST, the 19.0-MeV neutron fluence standard will be established by 2010, and development of high energy neutron standards above 20 MeV is also examined. An outline of the development of the high energy neutron standards is also shown in this paper. (author)

  18. A no-gold-standard technique for objective assessment of quantitative nuclear-medicine imaging methods.

    Science.gov (United States)

    Jha, Abhinav K; Caffo, Brian; Frey, Eric C

    2016-04-07

    The objective optimization and evaluation of nuclear-medicine quantitative imaging methods using patient data is highly desirable but often hindered by the lack of a gold standard. Previously, a regression-without-truth (RWT) approach has been proposed for evaluating quantitative imaging methods in the absence of a gold standard, but this approach implicitly assumes that bounds on the distribution of true values are known. Several quantitative imaging methods in nuclear-medicine imaging measure parameters where these bounds are not known, such as the activity concentration in an organ or the volume of a tumor. We extended upon the RWT approach to develop a no-gold-standard (NGS) technique for objectively evaluating such quantitative nuclear-medicine imaging methods with patient data in the absence of any ground truth. Using the parameters estimated with the NGS technique, a figure of merit, the noise-to-slope ratio (NSR), can be computed, which can rank the methods on the basis of precision. An issue with NGS evaluation techniques is the requirement of a large number of patient studies. To reduce this requirement, the proposed method explored the use of multiple quantitative measurements from the same patient, such as the activity concentration values from different organs in the same patient. The proposed technique was evaluated using rigorous numerical experiments and using data from realistic simulation studies. The numerical experiments demonstrated that the NSR was estimated accurately using the proposed NGS technique when the bounds on the distribution of true values were not precisely known, thus serving as a very reliable metric for ranking the methods on the basis of precision. In the realistic simulation study, the NGS technique was used to rank reconstruction methods for quantitative single-photon emission computed tomography (SPECT) based on their performance on the task of estimating the mean activity concentration within a known volume of interest

  19. A no-gold-standard technique for objective assessment of quantitative nuclear-medicine imaging methods

    International Nuclear Information System (INIS)

    Jha, Abhinav K; Frey, Eric C; Caffo, Brian

    2016-01-01

    The objective optimization and evaluation of nuclear-medicine quantitative imaging methods using patient data is highly desirable but often hindered by the lack of a gold standard. Previously, a regression-without-truth (RWT) approach has been proposed for evaluating quantitative imaging methods in the absence of a gold standard, but this approach implicitly assumes that bounds on the distribution of true values are known. Several quantitative imaging methods in nuclear-medicine imaging measure parameters where these bounds are not known, such as the activity concentration in an organ or the volume of a tumor. We extended upon the RWT approach to develop a no-gold-standard (NGS) technique for objectively evaluating such quantitative nuclear-medicine imaging methods with patient data in the absence of any ground truth. Using the parameters estimated with the NGS technique, a figure of merit, the noise-to-slope ratio (NSR), can be computed, which can rank the methods on the basis of precision. An issue with NGS evaluation techniques is the requirement of a large number of patient studies. To reduce this requirement, the proposed method explored the use of multiple quantitative measurements from the same patient, such as the activity concentration values from different organs in the same patient. The proposed technique was evaluated using rigorous numerical experiments and using data from realistic simulation studies. The numerical experiments demonstrated that the NSR was estimated accurately using the proposed NGS technique when the bounds on the distribution of true values were not precisely known, thus serving as a very reliable metric for ranking the methods on the basis of precision. In the realistic simulation study, the NGS technique was used to rank reconstruction methods for quantitative single-photon emission computed tomography (SPECT) based on their performance on the task of estimating the mean activity concentration within a known volume of interest

  20. Quench correction in liquid scintillation counting by a combined internal standard-samples channels ratio technique

    International Nuclear Information System (INIS)

    Dahlberg, E.

    1982-01-01

    A well-known problem in liquid scintillation counting (LSC) is that radioactivity cannot be measured with 100% efficiency, e.g., due to ''quenching'', which thus needs be corrected for. Three methods (viz., those of internal standard (IS), samples channels ratio (SCR), and external standard channels ratio (ESCR) are in common use to accomplish quench correction. None of these methods is ideal. This paper shows that a combination of the IS and SCR methods (IS-SCR) ameliorates the major disadvantages of both techniques and the disadvantage of the SCR technique at low count rates have been eliminated in the IS-SCR method, which also has a low volume dependence compared to the IS and ESCR methods. The IS-SCR method is not affected by time-dependent diffusion of solutes and solvents into the walls of plastic counting vials, which is a major drawback of the ESCR technique. Used with a simple linear regression technique, the IS-SCR quench curves may be linearized over wide ranges of efficiencies. In view of the wide-spread application of LSC, the IS-SCR technique is therefore likely to be useful to many investigators. 2 figures, 2 tables

  1. Assessment of Snared-Loop Technique When Standard Retrieval of Inferior Vena Cava Filters Fails

    International Nuclear Information System (INIS)

    Doody, Orla; Noe, Geertje; Given, Mark F.; Foley, Peter T.; Lyon, Stuart M.

    2009-01-01

    Purpose To identify the success and complications related to a variant technique used to retrieve inferior vena cava filters when simple snare approach has failed. Methods A retrospective review of all Cook Guenther Tulip filters and Cook Celect filters retrieved between July 2006 and February 2008 was performed. During this period, 130 filter retrievals were attempted. In 33 cases, the standard retrieval technique failed. Retrieval was subsequently attempted with our modified retrieval technique. Results The retrieval was successful in 23 cases (mean dwell time, 171.84 days; range, 5-505 days) and unsuccessful in 10 cases (mean dwell time, 162.2 days; range, 94-360 days). Our filter retrievability rates increased from 74.6% with the standard retrieval method to 92.3% when the snared-loop technique was used. Unsuccessful retrieval was due to significant endothelialization (n = 9) and caval penetration by the filter (n = 1). A single complication occurred in the group, in a patient developing pulmonary emboli after attempted retrieval. Conclusion The technique we describe increased the retrievability of the two filters studied. Hook endothelialization is the main factor resulting in failed retrieval and continues to be a limitation with these filters.

  2. On the optimality of double-bracket flows

    Directory of Open Access Journals (Sweden)

    Anthony M. Bloch

    2004-01-01

    Full Text Available We analyze the optimality of the stable fixed point of the double-bracket equations. We introduce different types of optimality and prove local and global optimality results with respect to the Schatten p-norms.

  3. Time-dependent constrained Hamiltonian systems and Dirac brackets

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Manuel de [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Madrid (Spain); Marrero, Juan C. [Departamento de Matematica Fundamental, Facultad de Matematicas, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands (Spain); Martin de Diego, David [Departamento de Economia Aplicada Cuantitativa, Facultad de Ciencias Economicas y Empresariales, UNED, Madrid (Spain)

    1996-11-07

    In this paper the canonical Dirac formalism for time-dependent constrained Hamiltonian systems is globalized. A time-dependent Dirac bracket which reduces to the usual one for time-independent systems is introduced. (author)

  4. Bond strengths evaluation of laser ceramic bracket debonding

    Science.gov (United States)

    Dostalová, T.; Jelinková, H.; Šulc, J.; Němec, M.; Fibrich, M.; Jelínek, M.; Michalík, P.; Bučková, M.

    2012-09-01

    Ceramic brackets often used for an orthodontic treatment can lead to problems such as enamel tear outs because of their low fracture resistance and high bond strengths. Therefore the aim of our study was to investigate the positive laser radiation effect on bracket debonding. Moreover, the influence of the enamel shape surface under the bracket and laser radiation power on the debonding strength was investigated. The source of the radiation was the longitudinally diode-pumped Tm:YAP laser operating at 1997 nm. To eliminate the tooth surface roughness the flat enamel surface was prepared artificially and the bracket was bonded on it. The debonding was accomplished by Tm:YAP laser radiation with different the power value while recording the temperature rise in the pulp. To simulate the debonding process in vivo the actual bond strength was measured by the digital force gauge. The results were analyzed by scanning electron microscope.

  5. Corrosion behavior of self-ligating and conventional metal brackets

    Directory of Open Access Journals (Sweden)

    Lúcio Henrique Esmeraldo Gurgel Maia

    2014-04-01

    Full Text Available Objective: To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. Methods: Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek metal brackets from three manufacturers (n = 150 were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± 1ºC for 21 days. The content of nickel, chromium and iron ions in the solution collected at intervals of 7, 14 and 21 days was quantified by atomic absorption spectrophotometry. After the aging process, the brackets were analyzed by scanning electron microscopy (SEM under 22X and 1,000X magnifications. Results: Comparison of metal release in self-ligating and conventional brackets from the same manufacturer proved that the SCs group released more nickel (p < 0.05 than the GN group after 7 and 14 days, but less chromium (p < 0.05 after 14 days and less iron (p < 0.05 at the three experimental time intervals. The INs group released less iron (p < 0.05 than the GE group after 7 days and less nickel, chromium and iron (p < 0.05 after 14 and 21 days. The ECs group released more nickel, chromium and iron (p < 0.05 than the VE group after 14 days, but released less nickel and chromium (p < 0.05 after 7 days and less chromium and iron (p < 0.05 after 21 days. The SEM analysis revealed alterations on surface topography of conventional and self-ligating brackets. Conclusions: The aging process in self-ligating brackets was not greater than in conventional brackets from the same manufacturer. The null hypothesis was accepted.

  6. Clinical evaluation of the failure rates of metallic brackets

    Directory of Open Access Journals (Sweden)

    Fábio Lourenço Romano

    2012-04-01

    Full Text Available OBJECTIVES: The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems. MATERIAL AND METHODS: Twenty patients (10.5-15.1 years old who had sought corrective orthodontic treatment at a University Orthodontic Clinic were evaluated. Brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: Orthodontic Concise, conventional Transbond XT, Transbond XT without primer, and Transbond XT associated with Transbond Plus Self-etching Primer (TPSEP. The 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. Initial archwires were inserted 1 week after bracket bonding. The number of bracket failures for each adhesive system was quantified over a 6-month period. RESULTS: The number of debonded brackets was: 8- Orthodontic Concise, 2- conventional Transbond XT, 9- Transbond XT without primer, and 1- Transbond XT + TPSEP. By using the Kaplan-Meier methods, statistically significant differences were found between the materials (p=0.0198, and the Logrank test identified these differences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systems were statistically superior to Orthodontic Concise and Transbond XT without primer (p<0.05. There was no statistically significant difference between the dental arches (upper and lower, between the dental arch sides (right and left, and among the quadrants. CONCLUSIONS: The largest number of bracket failures occurred with Orthodontic Concise and Transbond XT without primer systems and few bracket failures occurred with conventional Transbond XT and Transbond XT+TPSEP. More bracket failures were observed in the posterior region compared with the anterior region.

  7. A comparative study in three methods of bracket placement

    OpenAIRE

    Kanako, FUKUYO; Yasushi, NISHII; Kunihiko, NOJIMA; Hideharu, YAMAGUCHI; Imai Orthodontic Clinic; Department of Orthodontics, Tokyo Dental College; Department of Orthodontics, Tokyo Dental College; Department of Orthodontics, Tokyo Dental College

    2004-01-01

    Results of orthodontic treatment with the straight-wire appliances largely depend on bracket positioning. Forty subjects with individual normal occlusion (20 males, 20 females, mean age 23 years) were selected from Tokyo Dental College student. Their orthodontic diagnostic models were digitized with a laser scanner. Three bracket placement methods were compared : the FA Method, which bisects the clinical crown into the gingival and occlusal portions, the Height Method, which measures from the...

  8. Advanced Packaging Materials and Techniques for High Power TR Module: Standard Flight vs. Advanced Packaging

    Science.gov (United States)

    Hoffman, James Patrick; Del Castillo, Linda; Miller, Jennifer; Jenabi, Masud; Hunter, Donald; Birur, Gajanana

    2011-01-01

    The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires advances in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and compared to standard technologies.

  9. Extending and simplifying the standard Köhn-pipette technique for grain size analysis

    Science.gov (United States)

    Hirsch, Florian; Raab, Thomas

    2014-05-01

    Grain size distribution is a fundamental parameter to characterize physical properties of soils and sediments. Manifold approaches exist and according to the DIN ISO 11277 soil texture is analyzed by default with the combined pipette sieving and sedimentation method developed by Köhn. With this standard technique subfractions of sand and silt as well as the total clay content can be determined but the differentiation of clay subfractions is impossible. As the differentiation of the clay subfractions yields relevant information about pedogenesis, we present a protocol basing on standard techniques of granulometry with easy to handle and low cost equipment. The protocol was tested on a set of soil samples to cover the range of grain size distributions. We used a three-step procedure for achieving the grain size distribution of soil samples taking into account the subfractions of sand, silt and clay by a combination of sedimentation, centrifugal sedimentation and wet sieving. The pipetting was done with a piston-stroke pipette instead of the referred complex pipette from the DIN ISO 11277. Our first results show that the applied protocol is less prone to operating errors than the standard Köhn-pipette technique. Furthermore, even a less experienced laboratory worker can handle 10 samples in one day. Analyses of a luvisol profile, sampled in high spatial resolution, showed that the lessivation process is characterized by translocation of fine clay from the eluvial horizon to the illuvial horizon. Therefore our protocol is a fast alternative to detect lessivation, which is otherwise only clearly identifiable by micromorphological investigation and not by the standard Köhn-pipette technique.

  10. Impact of Standardized Communication Techniques on Errors during Simulated Neonatal Resuscitation.

    Science.gov (United States)

    Yamada, Nicole K; Fuerch, Janene H; Halamek, Louis P

    2016-03-01

    Current patterns of communication in high-risk clinical situations, such as resuscitation, are imprecise and prone to error. We hypothesized that the use of standardized communication techniques would decrease the errors committed by resuscitation teams during neonatal resuscitation. In a prospective, single-blinded, matched pairs design with block randomization, 13 subjects performed as a lead resuscitator in two simulated complex neonatal resuscitations. Two nurses assisted each subject during the simulated resuscitation scenarios. In one scenario, the nurses used nonstandard communication; in the other, they used standardized communication techniques. The performance of the subjects was scored to determine errors committed (defined relative to the Neonatal Resuscitation Program algorithm), time to initiation of positive pressure ventilation (PPV), and time to initiation of chest compressions (CC). In scenarios in which subjects were exposed to standardized communication techniques, there was a trend toward decreased error rate, time to initiation of PPV, and time to initiation of CC. While not statistically significant, there was a 1.7-second improvement in time to initiation of PPV and a 7.9-second improvement in time to initiation of CC. Should these improvements in human performance be replicated in the care of real newborn infants, they could improve patient outcomes and enhance patient safety. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  11. Outcome of oncoplastic breast-conserving surgery following bracketing wire localization for large breast cancer.

    Science.gov (United States)

    Malhaire, Caroline; Hequet, Delphine; Falcou, Marie-Christine; Feron, Jean-Guillaume; Tardivon, Anne; Leduey, Alexandre; Guillot, Eugénie; Mosseri, Véronique; Rouzier, Roman; Couturaud, Benoit; Reyal, Fabien

    2015-08-01

    The purpose of this study was to evaluate the outcome of breast conserving surgery comparing oncoplastic surgery (OS) and standard lumpectomy (SL) after preoperative bracketing wire localization of large neoplastic lesions. We retrospectively reviewed the medical records and the mammograms of patients operated on at the Institut Curie between May 2005 and September 2011 after bracketing wire localization under mammographic and/or sonographic guidance. 113 patients underwent surgery for a pre-operative diagnosis of DCIS (n = 80), micro-invasive carcinoma (n = 9) or invasive carcinoma (n = 24), by OS (n = 73) or SL (n = 40). In the OS group, radiological size (52 mm vs 39 mm, p breast cancer and one death unrelated to cancer occurred. Following bracketing wire localization, OS allowed the conserving management of significantly larger lesions with wider resection volumes, without significant increase in margin involvement or re-intervention rate, and equivalent rate of microcalcifications clearance compared to SL. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effect of dental bleaching after bracket bonding and debonding using three different adhesive systems

    Directory of Open Access Journals (Sweden)

    Lucianna de Oliveira Gomes

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the influence of bonding and debonding of orthodontic brackets on dental in-home bleaching, taking into account three different adhesive systems. METHODS: Forty-four bovine incisors were divided into four groups according to the primer system used for orthodontic bracket bonding. Following the debonding of orthodontic brackets, the teeth were stored in staining solution for 96 hours. Then, teeth were whitened using 10% carbamide peroxide for two weeks at a 6-hour-a-day regime. Standardized digital photographs were taken at the following intervals: T0 (initial; T1 (after debonding; T2 (after pigmentation; T3, T4 and T5 representing 1, 7, and 14 days of bleaching. Repeatability and stability tests were carried out to check the method accuracy. Images were analyzed using Adobe Photoshop 7.0 software considering (L*a*b*color coordinate values and a modified color difference total (Δ;E'. RESULTS: The results of this study (ANOVA and Tukey; p < 0.01 demonstrated that after 7 days of bleaching, experimental groups showed significantly less teeth whitening compared to the control group. However, there were no significant color differences between the groups after 14 days, according to values of lightness (L*. CONCLUSIONS: Regardless of the adhesive primer system applied, bonding and debonding of orthodontic brackets alters the outcome of tooth whitening in the first 7 days of bleaching, however it has no influence on the whitening of the dental structure after 14 days of in-home dental bleaching with 10% carbamide peroxide.

  13. Frictional resistances of metal-lined ceramic brackets versus conventional stainless steel brackets and development of 3-D friction maps.

    Science.gov (United States)

    Kusy, R P; Whitley, J Q

    2001-10-01

    The frictional resistances of 2 metal-lined ceramic brackets (Luxi and Clarity) were compared with 2 conventional stainless steel brackets (Mini-Taurus and Mini-Twin) in vitro. In method 1, we varied the second-order angulation from 0 degrees to 12 degrees while maintaining the normal or ligature force constant at 0.3 kg; in method 2, we varied the ligature force from 0.1 kg to 0.9 kg while maintaining the angulation at theta = 0 degrees or theta = 11 degrees. The hardware simulated a 3-bracket system in which the interbracket distances were always 18 mm. All couples were evaluated at 34 degrees C using the same size stainless steel archwire (19 x 26 mil) and ligature wire (10 mil). In the passive region, the static and kinetic frictional forces and coefficients of friction were key parameters; in the active region, the static and kinetic binding forces and coefficients of binding were critical parameters. From outcomes of methods 1 and 2, the 4 aforementioned parameters, and a knowledge of the critical contact angle for binding, 3-dimensional friction maps were constructed in the dry and wet states from which the frictional resistances could be determined at any ligature force or second-order angulation. Those 3-dimensional maps show that metal-lined ceramic brackets can function comparably to conventional stainless steel brackets and that 18-kt gold inserts appear superior to stainless steel inserts. As the morphologies of metal inserts are improved, these metal-lined ceramic brackets will provide not only good esthetics among ceramic brackets but also minimal friction among conventionally ligated brackets.

  14. Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

    Directory of Open Access Journals (Sweden)

    Leonard Euler Andrade Gomes do Nascimento

    2014-01-01

    Full Text Available OBJECTIVE: To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating influences adhesion and formation of Streptococcus mutans colonies. METHODS: Search strategy: four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME were selected to search relevant articles covering the period from January 1965 to December 2012. Selection Criteria: in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria. Data collection and analysis: Two reviewers independently extracted data using the keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted. RESULTS: The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design. CONCLUSIONS: Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating over colony formation and adhesion of Streptococcus mutans.

  15. A comparative in vitro study of frictional resistance between lingual brackets and stainless steel archwires.

    Science.gov (United States)

    Ozturk Ortan, Yildiz; Yurdakuloglu Arslan, Tugce; Aydemir, Bulent

    2012-02-01

    Friction between archwires and labial brackets has received considerable attention; however, information on the frictional behaviour of commercially available lingual brackets is limited. The aim of this study was to investigate the frictional resistance resulting from a combination of lingual orthodontic brackets (7th Generation, STb, Magic, and In-Ovation L) and stainless steel archwires at 0, 5, and 10 degrees of second-order angulation. Each bracket type (n = 30) was tested with three different sizes of archwires. Static and kinetic frictional forces were evaluated with a universal testing machine. Statistical analysis of the data was performed with non-parametric Kruskal-Wallis and Dunn's multiple comparison tests. All tested brackets showed higher frictional forces as the wire size and second-order angulation increased. The lowest friction was found with In-Ovation L brackets and 0.016 inch archwires at 0 degrees angulation, and the greatest friction with a combination of STb brackets and 0.017 × 0.025 inch archwires at 10 degrees angulation. For all combinations, Magic and In-Ovation L brackets showed lower frictional resistance when compared with 7th Generation and STb brackets. The slot width (occluso-gingival dimension) of the brackets, measured using the optics of a microhardness machine, showed that all brackets were oversized and that Magic brackets had the largest slot width. Surface roughness of the brackets investigated using atomic force microscopy and scanning electron microscopy, demonstrated that the 7th Generation brackets had the greatest surface roughness.

  16. Standard practice for monitoring atmospheric SO2 using the sulfation plate technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This practice covers a weighted average effective SO2 level for a 30-day interval through the use of the sulfation plate method, a technique for estimating the effective SO2 content of the atmosphere, and especially with regard to the atmospheric corrosion of stationary structures or panels. This practice is aimed at determining SO2 levels rather than sulfuric acid aerosol or acid precipitation. 1.2 The results of this practice correlate approximately with volumetric SO2 concentrations, although the presence of dew or condensed moisture tends to enhance the capture of SO2 into the plate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  17. Comparisons of neural networks to standard techniques for image classification and correlation

    Science.gov (United States)

    Paola, Justin D.; Schowengerdt, Robert A.

    1994-01-01

    Neural network techniques for multispectral image classification and spatial pattern detection are compared to the standard techniques of maximum-likelihood classification and spatial correlation. The neural network produced a more accurate classification than maximum-likelihood of a Landsat scene of Tucson, Arizona. Some of the errors in the maximum-likelihood classification are illustrated using decision region and class probability density plots. As expected, the main drawback to the neural network method is the long time required for the training stage. The network was trained using several different hidden layer sizes to optimize both the classification accuracy and training speed, and it was found that one node per class was optimal. The performance improved when 3x3 local windows of image data were entered into the net. This modification introduces texture into the classification without explicit calculation of a texture measure. Larger windows were successfully used for the detection of spatial features in Landsat and Magellan synthetic aperture radar imagery.

  18. Prototype to measure bracket debonding force in vivo

    Directory of Open Access Journals (Sweden)

    Jéssika Lagni Tonus

    Full Text Available ABSTRACT Introduction: Material biodegradation that occurs in the mouth may interfere in the bonding strength between the bracket and the enamel, causing lower bond strength values in vivo, in comparison with in vitro studies. Objective: To develop a prototype to measure bracket debonding force in vivo and to evaluate, in vitro, the bond strength obtained with the prototype. Methods: A original plier (3M Unitek was modified by adding one strain gauge directly connected to its claw. An electronic circuit performed the reading of the strain gauge, and the software installed in a computer recorded the values of the bracket debonding force, in kgf. Orthodontic brackets were bonded to the facial surface of 30 bovine incisors with adhesive materials. In Group 1 (n = 15, debonding was carried out with the prototype, while tensile bond strength testing was performed in Group 2 (n = 15. A universal testing machine was used for the second group. The adhesive remnant index (ARI was recorded. Results: According to Student’s t test (α = 0.05, Group 1 (2.96 MPa and Group 2 (3.08 MPa were not significantly different. ARI score of 3 was predominant in the two groups. Conclusion: The prototype proved to be reliable for obtaining in vivo bond strength values for orthodontic brackets.

  19. Outcome of a standardized technique of preputial preservation surgery for phimosis: A single institutional experience

    Directory of Open Access Journals (Sweden)

    Kamalesh Pal

    2014-01-01

    Full Text Available Introduction: Pathological phimosis or preputial stenosis is a distressing problem in children leading to recurrent balanoposthitis, ballooning of prepuce, and rarely back pressure changes in the urinary tract. Circumcision has been the standard of care for such situations, although recently, various alternatives to circumcision have been reported in the literature. Most of these techniques are often complex and are met with poor acceptance. Moreover, besides personal preferences (in Hindus, advantages of preputial preservation is increasingly being realized recently. Materials and Methods: A prospective study was carried out in which a simple standardized technique of preputioplasty (dorsal slit was used in 40 pediatric preputial stenosis cases. The outcome of this procedure including cosmesis and parental satisfaction was evaluated. Results: The average duration of this procedure was from 10 to 25 min with no intraoperative complications. The cosmetic outcome was good in 62.5%, satisfactory in 30%, and poor in 7.5% of cases. All of the boys had retractable prepuce with no functional problems. There was 100% parental satisfaction. None of the patients required a redo procedure or circumcision. Conclusion: A dorsal slit of adequate length i.e.; 1/3 rd the length from the corona to the tip leads to a satisfactory cosmetic outcome in more than 92% of cases. Preputioplasty is a safe and simple alternative to more radical procedure of circumcision.

  20. Self-ligating brackets in orthodontics. A systematic review.

    Science.gov (United States)

    Fleming, Padhraig S; Johal, Ama

    2010-05-01

    To evaluate the clinical differences in relation to the use of self-ligating brackets in orthodontics. 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. 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. 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.

  1. Bering's proposal for boundary contribution to the Poisson bracket

    International Nuclear Information System (INIS)

    Soloviev, V.O.

    1998-11-01

    It is shown that the Poisson bracket with boundary terms recently proposed by Bering can be deduced from the Poisson bracket proposed by the present author if one omits terms free of Euler-Lagrange derivatives (''annihilation principle''). This corresponds to another definition of the formal product of distributions (or, saying it in other words, to another definition of the pairing between 1-forms and 1-vectors in the formal variational calculus). We extend the formula initially suggested by Bering only for the ultralocal case with constant coefficients onto the general non-ultralocal brackets with coefficients depending on fields and their spatial derivatives. The lack of invariance under changes of dependent variables (field redefinitions) seems a drawback of this proposal. (author)

  2. Therapeutic accuracy of individualized brackets in lingual orthodontics.

    Science.gov (United States)

    Pauls, Alexander Harry

    2010-09-01

    Verification of the therapeutic accuracy of the Incognito ® bracket system. The therapeutic set-up casts and final treatment casts were digitalized using a 3D scanner, and the scans were subsequently superimposed. The deviations in rotation and translation of each tooth in the three spatial dimensions were calculated. The front teeth showed deviations in rotations of less than 4.6 ° and in translations under 0.5 mm. In addition, influences such as upper or lower jaw, growth, type of tooth, anterior tooth position, bracket generation, 3D scanner hardware and finishing archwires were analyzed. The clinical impression was confirmed by the measurements taken in this study. The final results following lingual orthodontic treatment using individualized brackets correlate satisfactorily with the therapeutic set-ups.

  3. Force loss in archwire-guided tooth movement of conventional and self-ligating brackets.

    Science.gov (United States)

    Montasser, Mona A; El-Bialy, Tarek; Keilig, Ludger; Reimann, Susanne; Jäger, Andreas; Bourauel, Christoph

    2014-02-01

    This study aimed to investigate the differences in the force loss during simulated archwire-guided canine retraction between various conventional and self-ligating brackets. Three types of orthodontic brackets have been investigated experimentally using a biomechanical set-up: 1. conventional ligating brackets (Victory Series and Mini-Taurus), 2. self-ligating brackets (SmartClip: passive self-ligating bracket, and Time3 and SPEED: active self-ligating brackets), and 3. a conventional low-friction bracket (Synergy). All brackets had a nominal 0.022″ slot size. The brackets were combined with three rectangular 0.019×0.025″ archwires: 1. Remanium (stainless steel), 2. Nitinol SE (nickel-titanium alloy, NiTi), and 3. Beta III Titanium (titanium-molybdenum alloy). Stainless steel ligatures were used with the conventional brackets. Archwire-guided tooth movement was simulated over a retraction path of up to 4mm using a superelastic NiTi coil spring (force: 1 N). Force loss was lowest for the Victory Series and SmartClip brackets in combination with the steel guiding archwire (35 and 37.6 per cent, respectively) and highest for the SPEED and Mini-Taurus brackets in combination with the titanium wire (73.7 and 64.4 per cent, respectively). Force loss gradually increased by 10 per cent for each bracket type in combination with the different wires in the following sequence: stainless steel, Nitinol, and beta-titanium. Self-ligating brackets did not show improved performance compared with conventional brackets. There was no consistent pattern of force loss when comparing conventional and self-ligating brackets or passive and active self-ligating brackets.

  4. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques

    Science.gov (United States)

    Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

    2014-01-01

    On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent. PMID:25525356

  5. Study of the standard direct costs of various techniques of advanced endoscopy. Comparison with surgical alternatives.

    Science.gov (United States)

    Loras, Carme; Mayor, Vicenç; Fernández-Bañares, Fernando; Esteve, Maria

    2018-03-12

    The complexity of endoscopy has carried out an increase in cost that has a direct effect on the healthcare systems. However, few studies have analyzed the cost of advanced endoscopic procedures (AEP). To carry out a calculation of the standard direct costs of AEP, and to make a financial comparison with their surgical alternatives. Calculation of the standard direct cost in carrying out each procedure. An endoscopist detailed the time, personnel, materials, consumables, recovery room time, stents, pathology and medication used. The cost of surgical procedures was the average cost recorded in the hospital. Thirty-eight AEP were analyzed. The technique showing lowest cost was gastroscopy + APC (€116.57), while that with greatest cost was ERCP with cholangioscopy + stent placement (€5083.65). Some 34.2% of the procedures registered average costs of €1000-2000. In 57% of cases, the endoscopic alternative was 2-5 times more cost-efficient than surgery, in 31% of cases indistinguishable or up to 1.4 times more costly. Standard direct cost of the majority of AEP is reported using a methodology that enables easy application in other centers. For the most part, endoscopic procedures are more cost-efficient than the corresponding surgical procedure. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  6. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques.

    Science.gov (United States)

    Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

    2014-01-01

    On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent.

  7. Air-powder polishing on self-ligating brackets after clinical use: effects on debris levels

    Directory of Open Access Journals (Sweden)

    Mônica L. S. Castro Aragón

    Full Text Available ABSTRACT Introduction: Debris buildup on brackets and arch surfaces is one of the main factors that can influence the intensity of friction between bracket and orthodontic wire. Objective: This study sought to evaluate the effect of air-powder polishing cleaning on debris levels of self-ligating ceramic brackets at the end of orthodontic treatment, compared to the behavior of conventional brackets. Methods: Debris levels were evaluated in metal conventional orthodontic brackets (n = 42 and ceramic self-ligating brackets (n = 42 on canines and premolars, arranged in pairs. There were brackets with and without air-powder polishing. At the end of orthodontic treatment, a hemiarch served as control and the contralateral hemiarch underwent prophylaxis with air-powder polishing. Debris buildup in bracket slots was assessed through images, and Wilcoxon test was used to analyze the results. Results: The median debris levels were statistically lower in the conventional metal brackets compared to self-ligating ones (p = 0.02, regarding brackets not submitted to air-powder polishing. Polishing significantly reduced debris buildup to zero in both systems, without differences between groups. Conclusions: Ceramic self-ligating brackets have a higher debris buildup in comparison to conventional metal brackets in vivo, but prophylaxis with sodium bicarbonate jet was effective in reducing debris levels in self-ligating and also in conventional brackets.

  8. Open Partial Nephrectomy in Renal Cancer: A Feasible Gold Standard Technique in All Hospitals

    Directory of Open Access Journals (Sweden)

    J. M. Cozar

    2008-01-01

    Full Text Available Introduction. Partial nephrectomy (PN is playing an increasingly important role in localized renal cell carcinoma (RCC as a true alternative to radical nephrectomy. With the greater experience and expertise of surgical teams, it has become an alternative to radical nephrectomy in young patients when the tumor diameter is 4 cm or less in almost all hospitals since cancer-specific survival outcomes are similar to those obtained with radical nephrectomy. Materials and Methods. The authors comment on their own experience and review the literature, reporting current indications and outcomes including complications. The surgical technique of open partial nephrectomy is outlined. Conclusions. Nowadays, open PN is the gold standard technique to treat small renal masses, and all nonablative techniques must pass the test of time to be compared to PN. It is not ethical for patients to undergo radical surgery just because the urologists involved do not have adequate experience with PN. Patients should be involved in the final treatment decision and, when appropriate, referred to specialized centers with experience in open or laparoscopic partial nephrectomies.

  9. Comparative analysis of photograph-based clinical goniometry to standard techniques.

    Science.gov (United States)

    Crasto, Jared A; Sayari, Arash J; Gray, Robert R-L; Askari, Morad

    2015-06-01

    Assessment of joint range of motion (ROM) is an accepted evaluation of disability as well as an indicator of recovery from musculoskeletal injuries. Many goniometric techniques have been described to measure ROM, with variable validity due to inter-rater reliability. In this report, we assessed the validity of photograph-based goniometry in measurement of ROM and its inter-rater reliability and compared it to two other commonly used techniques. We examined three methods for measuring ROM in the upper extremity: manual goniometry (MG), visual estimations (VE), and photograph-based goniometry (PBG). Eight motions of the upper extremity were measured in 69 participants at an academic medical center. We found visual estimations and photograph-based goniometry to be clinically valid when tested against manual goniometry (r avg. 0.58, range 0.28 to 0.87). Photograph-based measurements afforded a satisfactory degree of inter-rater reliability (ICC avg. 0.77, range 0.28 to 0.96). Our study supports photograph-based goniometry as the new standard goniometric technique, as it has been clinically validated, is performed with greater consistency and better inter-rater reliability when compared with manual goniometry. It also allows for better documentation of measurements and potential incorporation into medical records in direct contrast to visual estimation.

  10. MATLAB Toolboxes for Reference Electrode Standardization Technique (REST) of Scalp EEG.

    Science.gov (United States)

    Dong, Li; Li, Fali; Liu, Qiang; Wen, Xin; Lai, Yongxiu; Xu, Peng; Yao, Dezhong

    2017-01-01

    Reference electrode standardization technique (REST) has been increasingly acknowledged and applied as a re-reference technique to transform an actual multi-channels recordings to approximately zero reference ones in electroencephalography/event-related potentials (EEG/ERPs) community around the world in recent years. However, a more easy-to-use toolbox for re-referencing scalp EEG data to zero reference is still lacking. Here, we have therefore developed two open-source MATLAB toolboxes for REST of scalp EEG. One version of REST is closely integrated into EEGLAB, which is a popular MATLAB toolbox for processing the EEG data; and another is a batch version to make it more convenient and efficient for experienced users. Both of them are designed to provide an easy-to-use for novice researchers and flexibility for experienced researchers. All versions of the REST toolboxes can be freely downloaded at http://www.neuro.uestc.edu.cn/rest/Down.html, and the detailed information including publications, comments and documents on REST can also be found from this website. An example of usage is given with comparative results of REST and average reference. We hope these user-friendly REST toolboxes could make the relatively novel technique of REST easier to study, especially for applications in various EEG studies.

  11. Gyrokinetic energy conservation and Poisson-bracket formulation

    International Nuclear Information System (INIS)

    Brizard, A.

    1988-11-01

    An integral expression for the gyrokinetic total energy of a magnetized plasma with general magnetic field configuration perturbed by fully electromagnetic fields was recently derived through the use of a gyro-center Lie transformation. We show that the gyrokinetic energy is conserved by the gyrokinetic Hamiltonian flow to all orders in perturbed fields. This paper is concerned with the explicit demonstration that a gyrokinetic Hamiltonian containing quadratic nonlinearities preserves the gyrokinetic energy up to third order. The Poisson-bracket formulation greatly facilitates this demonstration with the help of the Jacobi identity and other properties of the Poisson brackets. 18 refs

  12. Are neck nodal volumes drawn on CT slices covered by standard three-field technique?

    Science.gov (United States)

    Sanguineti, Giuseppe; Culp, Laura R; Endres, Eugene J; Bayouth, John E

    2004-07-01

    Several definitions have been proposed in the past few years on how to contour the various neck nodal levels on CT slices. However, whether the resulting nodal volumes would have been covered by standard techniques is unknown. The purpose of this study was to clarify this issue. Eight patients (N0-N1) with head-and-neck cancer from various primary sites referred to us for definitive radiotherapy were included in this study. Two observers contoured the level Ib-V neck nodal volumes on planning CT according to seven reported definitions. Each observer also drew blocks on digitally reconstructed radiographs for the initial (on-cord) phase of a standard three-field technique (parallel opposed lateral fields and AP supraclavicular field) for three different clinical settings: "medium" larynx (to cover upper, mid, and low jugular nodes), "big" larynx (same as for medium, plus posterior cervical nodes), and "tonsil" (same as for big plus retropharyngeal nodes). Fields blocks were concentrically reduced 5 mm in all directions as a surrogate for the clinical target volume to planning target volume expansion. A plan was created for each of the clinical settings, delivering 2 Gy to the International Commission on Radiation Units and Measurements reference point. The coverage of the nodal levels according to the various definitions was investigated throughout the analysis of the volume receiving 50%, 80%, and 95% of the prescribed dose (V(50), V(80), and V(95), respectively) and dose covering at least 95% of the volume (D(95)) values extracted from their cumulative dose-volume histograms in the three clinical settings. The V(50) coverage of levels III and IV was adequate for all definitions and trials. For level V, about 3-5% of the volume was outside the 50% isodose of those trials that targeted the posterior cervical chain. Coverage of level Ib was highly dependent on the definition, with up to 21% of the volume outside the standard tonsillar fields. For level II, although

  13. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Science.gov (United States)

    2010-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin... composed of an adhesive compound, such as polymethylmethacrylate, intended to cement an orthodontic bracket...

  14. A standardized infrared imaging technique that specifically detects UCP1-mediated thermogenesis in vivo.

    Science.gov (United States)

    Crane, Justin D; Mottillo, Emilio P; Farncombe, Troy H; Morrison, Katherine M; Steinberg, Gregory R

    2014-07-01

    The activation and expansion of brown adipose tissue (BAT) has emerged as a promising strategy to counter obesity and the metabolic syndrome by increasing energy expenditure. The subsequent testing and validation of novel agents that augment BAT necessitates accurate pre-clinical measurements in rodents regarding the capacity for BAT-derived thermogenesis. We present a novel method to measure BAT thermogenesis using infrared imaging following β3-adrenoreceptor stimulation in mice. We show that the increased body surface temperature observed using this method is due solely to uncoupling protein-1 (UCP1)-mediated thermogenesis and that this technique is able to discern differences in BAT activity in mice acclimated to 23 °C or thermoneutrality (30 °C). These findings represent the first standardized method utilizing infrared imaging to specifically detect UCP1 activity in vivo.

  15. Friction in Sliding Orthodontic Mechanics: Ceramic Brackets, Teflon-Coated Wires and Comparative Resistances

    Science.gov (United States)

    1989-01-01

    N Tn FRICTION IN SLIDING ORTHODONTIC MECHANICS: N CERAMIC BRACKETS, TEFLON-COATED WIRES , AND COMPARATIVE RESISTANCES 0 DTICSFLECTED James R. Gill1...obsolete. SECURITY CLASSIFICATION OF THIS PAGE AFIT/CI "OVERPRINT" I FRICTION IN SLIDING ORTHODONTIC MECHANICS: CERAMIC BRACKETS, TEFLON-COATED WIRES ...brackets, arch- wires , and ligations during simulated orthodontic edgewise sliding mechanics. Independent variables and their values were 1) bracket

  16. Standardization of Berberis aristata extract through conventional and modern HPTLC techniques

    Directory of Open Access Journals (Sweden)

    Dinesh K. Patel

    2012-05-01

    Full Text Available Objective: Berberis aristata (Berberidaceae is an important medicinal plant, found in the different region of the world. It has significant medicinal value in the traditional Indian and Chinese system of medicine. The aim of the present investigation includes qualitative and quantitative analysis of Berberis aristata extract. Methods: Present study includes determination of phytochemical analysis, solubility test, heavy metal analysis, antimicrobial study and quantitative analysis by HPTLC method. Results: Preliminary phytochemical analysis showed the presence of carbohydrate, glycoside, alkaloid, protein, amino acid, saponin, tannin and flavonoid. Solubility in water and alcohal were found to be 81.90% in water and 84.52% in 50% in alcohal. Loss on drying was found to be 5.32%. Total phenol and flavonoid content were found to be 0.11% and 2.8%. Level of lead, arsenic, mercury and cadmium complies the standard level. E. coli and salmonella was found to be absent whereas total bacterial count, yeast and moulds contents were found to be under the limit. Content of berberine was found to be 13.47% through HPTLC techniques. Conclusions: The results obtained from the present studies could be used as source of valuable information which can play an important role for the food scientists, researchers and even the consumers for its standards.

  17. A standardized technique for high-pressure cooling of protein crystals.

    Science.gov (United States)

    Quirnheim Pais, David; Rathmann, Barbara; Koepke, Juergen; Tomova, Cveta; Wurzinger, Paul; Thielmann, Yvonne

    2017-12-01

    Cryogenic temperatures slow down secondary radiation damage during data collection from macromolecular crystals. In 1973, cooling at high pressure was identified as a method for cryopreserving crystals in their mother liquor [Thomanek et al. (1973). Acta Cryst. A29, 263-265]. Results from different groups studying different crystal systems indicated that the approach had merit, although difficulties in making the process work have limited its widespread use. Therefore, a simplified and reliable technique has been developed termed high-pressure cooling (HPC). An essential requirement for HPC is to protect crystals in capillaries. These capillaries form part of new sample holders with SPINE standard dimensions. Crystals are harvested with the capillary, cooled at high pressure (220 MPa) and stored in a cryovial. This system also allows the usage of the standard automation at the synchrotron. Crystals of hen egg-white lysozyme and concanavalin A have been successfully cryopreserved and yielded data sets to resolutions of 1.45 and 1.35 Å, respectively. Extensive work has been performed to define the useful working range of HPC in capillaries with 250 µm inner diameter. Three different 96-well crystallization screens that are most frequently used in our crystallization facility were chosen to study the formation of amorphous ice in this cooling setup. More than 89% of the screening solutions were directly suitable for HPC. This achievement represents a drastic improvement for crystals that suffered from cryoprotection or were not previously eligible for cryoprotection.

  18. Comparison of the initial orthodontic force systems produced by a new lingual bracket system and a straight-wire appliance.

    Science.gov (United States)

    Fuck, Lars-Michael; Wiechmann, Dirk; Drescher, Dieter

    2005-09-01

    Over the last few years, lingual appliances have become an established orthodontic treatment technique. Many studies have concentrated on various esthetic aspects, on laboratory and clinical procedures, and on patient comfort and compliance. The orthodontic force systems of these appliances, however, have not yet been investigated. The aim of this study was thus to determine the forces and moments produced by a new lingual bracket system during the leveling phase of orthodontic treatment and to compare those with the corresponding force system of a labial straight-wire appliance. The intra-oral situation of ten patients undergoing orthodontic treatment was replicated in measurement casts fitted with lingual and labial brackets. Special care was taken to precisely reproduce each patient's interbracket geometry. We measured each tooth's force systems as generated by a leveling arch inserted into the lingual and labial brackets. The resulting force systems of both appliances were found to be quite similar with regard to the magnitude of most force and moment components. Only the first molars were subjected to considerably greater single forces with the lingual appliance. Tipping moments were found to be significantly smaller with the lingual technique, whereas the rotational moments were significantly smaller with the labial appliance. All in all we noted significant differences between the two techniques only in certain areas which upon closer examination were distributed over only a few tooth types. The initial force systems produced by the new lingual bracket system proved to be comparable with those delivered by a conventional straight-wire appliance. The actual levels of forces and moments, however, were found in certain cases to be too heavy with both techniques. We therefore recommend the development of leveling wires producing considerably lighter forces and moments.

  19. Dosimetric comparison of intensity modulated radiotherapy techniques and standard wedged tangents for whole breast radiotherapy

    International Nuclear Information System (INIS)

    Fong, Andrew; Bromley, Regina; Beat, Mardi; Vien, Din; Dineley, Jude; Morgan, Graeme

    2009-01-01

    Full text: Prior to introducing intensity modulated radiotherapy (IMRT) for whole breast radiotherapy (WBRT) into our department we undertook a comparison of the dose parameters of several IMRT techniques and standard wedged tangents (SWT). Our aim was to improve the dose distribution to the breast and to decrease the dose to organs at risk (OAR): heart, lung and contralateral breast (Contra Br). Treatment plans for 20 women (10 right-sided and 10 left-sided) previously treated with SWT for WBRT were used to compare (a) SWT; (b) electronic compensators IMRT (E-IMRT); (c) tangential beam IMRT (T-IMRT); (d) coplanar multi-field IMRT (CP-IMRT); and (e) non-coplanar multi-field IMRT (NCP-IMRT). Plans for the breast were compared for (i) dose homogeneity (DH); (ii) conformity index (CI); (iii) mean dose; (iv) maximum dose; (v) minimum dose; and dose to OAR were calculated (vi) heart; (vii) lung and (viii) Contra Br. Compared with SWT, all plans except CP-IMRT gave improvement in at least two of the seven parameters evaluated. T-IMRT and NCP-IMRT resulted in significant improvement in all parameters except DH and both gave significant reduction in doses to OAR. As on initial evaluation NCP-IMRT is likely to be too time consuming to introduce on a large scale, T-IMRT is the preferred technique for WBRT for use in our department.

  20. Cost minimisation analysis of using acellular dermal matrix (Strattice™) for breast reconstruction compared with standard techniques.

    Science.gov (United States)

    Johnson, R K; Wright, C K; Gandhi, A; Charny, M C; Barr, L

    2013-03-01

    We performed a cost analysis (using UK 2011/12 NHS tariffs as a proxy for cost) comparing immediate breast reconstruction using the new one-stage technique of acellular dermal matrix (Strattice™) with implant versus the standard alternative techniques of tissue expander (TE)/implant as a two-stage procedure and latissimus dorsi (LD) flap reconstruction. Clinical report data were collected for operative time, length of stay, outpatient procedures, and number of elective and emergency admissions in our first consecutive 24 patients undergoing one-stage Strattice reconstruction. Total cost to the NHS based on tariff, assuming top-up payments to cover Strattice acquisition costs, was assessed and compared to the two historical control groups matched on key variables. Eleven patients having unilateral Strattice reconstruction were compared to 10 having TE/implant reconstruction and 10 having LD flap and implant reconstruction. Thirteen patients having bilateral Strattice reconstruction were compared to 12 having bilateral TE/implant reconstruction. Total costs were: unilateral Strattice, £3685; unilateral TE, £4985; unilateral LD and implant, £6321; bilateral TE, £5478; and bilateral Strattice, £6771. The cost analysis shows a financial advantage of using acellular dermal matrix (Strattice) in unilateral breast reconstruction versus alternative procedures. The reimbursement system in England (Payment by Results) is based on disease-related groups similar to that of many countries across Europe and tariffs are based on reported hospital costs, making this analysis of relevance in other countries. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. A Critical Appraisal of Techniques, Software Packages, and Standards for Quantitative Proteomic Analysis

    Science.gov (United States)

    Lawless, Craig; Hubbard, Simon J.; Fan, Jun; Bessant, Conrad; Hermjakob, Henning; Jones, Andrew R.

    2012-01-01

    Abstract New methods for performing quantitative proteome analyses based on differential labeling protocols or label-free techniques are reported in the literature on an almost monthly basis. In parallel, a correspondingly vast number of software tools for the analysis of quantitative proteomics data has also been described in the literature and produced by private companies. In this article we focus on the review of some of the most popular techniques in the field and present a critical appraisal of several software packages available to process and analyze the data produced. We also describe the importance of community standards to support the wide range of software, which may assist researchers in the analysis of data using different platforms and protocols. It is intended that this review will serve bench scientists both as a useful reference and a guide to the selection and use of different pipelines to perform quantitative proteomics data analysis. We have produced a web-based tool (http://www.proteosuite.org/?q=other_resources) to help researchers find appropriate software for their local instrumentation, available file formats, and quantitative methodology. PMID:22804616

  2. Torque expression of 0.018 and 0.022 inch conventional brackets

    NARCIS (Netherlands)

    Sifakakis, I.; Pandis, N.; Makou, M.; Eliades, T.; Katsaros, C.; Bourauel, C.

    2013-01-01

    The aim of this study was to assess the effect of the moments generated with low- and high-torque brackets. Four different bracket prescription-slot combinations of the same bracket type (Mini Diamond(R) Twin) were evaluated: high-torque 0.018 and 0.022 inch and low-torque 0.018 and 0.022 inch.

  3. On covariant Poisson brackets in classical field theory

    International Nuclear Information System (INIS)

    Forger, Michael; Salles, Mário O.

    2015-01-01

    How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on “multisymplectic Poisson brackets,” together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls–De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic “multisymplectic Poisson bracket” already proposed in the 1970s can be derived from the Peierls–De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra

  4. The Quantum Poisson Bracket and Transformation Theory in ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 8. The Quantum Poisson Bracket and Transformation Theory in Quantum Mechanics: Dirac's Early Work in Quantum Theory. Kamal Datta. General Article Volume 8 Issue 8 August 2003 pp 75-85 ...

  5. Poisson cohomology of scalar multidimensional Dubrovin-Novikov brackets

    Science.gov (United States)

    Carlet, Guido; Casati, Matteo; Shadrin, Sergey

    2017-04-01

    We compute the Poisson cohomology of a scalar Poisson bracket of Dubrovin-Novikov type with D independent variables. We find that the second and third cohomology groups are generically non-vanishing in D > 1. Hence, in contrast with the D = 1 case, the deformation theory in the multivariable case is non-trivial.

  6. Rheocasting an engine mounting bracket in commercial 7075

    CSIR Research Space (South Africa)

    Curle, UA

    2011-07-01

    Full Text Available -1 Light Metals Technology V, the 5th International Conference on Light Metals Technology, July 19- 22, 2011, Luneburg, Germany Rheocasting an engine mounting bracket in commercial 7075 CURLE Ulyate Andries1, a 1Materials Science and Manufacturing...

  7. On covariant Poisson brackets in classical field theory

    Energy Technology Data Exchange (ETDEWEB)

    Forger, Michael [Instituto de Matemática e Estatística, Universidade de São Paulo, Caixa Postal 66281, BR–05315-970 São Paulo, SP (Brazil); Salles, Mário O. [Instituto de Matemática e Estatística, Universidade de São Paulo, Caixa Postal 66281, BR–05315-970 São Paulo, SP (Brazil); Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Campus Universitário – Lagoa Nova, BR–59078-970 Natal, RN (Brazil)

    2015-10-15

    How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on “multisymplectic Poisson brackets,” together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls–De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic “multisymplectic Poisson bracket” already proposed in the 1970s can be derived from the Peierls–De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra.

  8. Flow Diversion versus Standard Endovascular Techniques for the Treatment of Unruptured Carotid-Ophthalmic Aneurysms.

    Science.gov (United States)

    Di Maria, F; Pistocchi, S; Clarençon, F; Bartolini, B; Blanc, R; Biondi, A; Redjem, H; Chiras, J; Sourour, N; Piotin, M

    2015-12-01

    Over the past few years, flow diversion has been increasingly adopted for the treatment of intracranial aneurysms, especially in the paraclinoid and paraophthalmic carotid segment. We compared clinical and angiographic outcomes and complication rates in 2 groups of patients with unruptured carotid-ophthalmic aneurysms treated for 7 years by either standard coil-based techniques or flow diversion. From February 2006 to December 2013, 162 unruptured carotid-ophthalmic aneurysms were treated endovascularly in 138 patients. Sixty-seven aneurysms were treated by coil-based techniques in 61 patients. Flow diverters were deployed in 95 unruptured aneurysms (77 patients), with additional coiling in 27 patients. Complication rates, clinical outcome, and immediate and long-term angiographic results were retrospectively analyzed. No procedure-related deaths occurred. Four procedure-related thromboembolic events (6.6%) leading to permanent morbidity in 1 case (1.6%) occurred in the coiling group. Neurologic complications were observed in 6 patients (7.8%) in the flow-diversion group, resulting in 3.9% permanent morbidity. No statistically significant difference was found between complication (P = .9) and morbidity rates (P = .6). In the coiling group (median follow-up, 31.5 ± 24.5 months), recanalization occurred at 1 year in 23/50 (54%) aneurysms and 27/55 aneurysms (50.9%) at the latest follow-up, leading to retreatment in 6 patients (9%). In the flow-diversion group (mean follow-up, 13.5 ± 10.8 months), 85.3% (35/41) of all aneurysms were occluded after 12 months, and 74.6% (50/67) on latest follow-up. The retreatment rate was 2.1%. Occlusion rates between the 2 groups differed significantly at 12 months (P < .001) and at the latest follow-up (P < .005). Our retrospective analysis shows better long-term occlusion of carotid-ophthalmic aneurysms after use of flow diverters compared with standard coil-based techniques, without significant differences in permanent morbidity

  9. The “excluding” suture technique for surgical closure of ventricular septal defects: A retrospective study comparing the standard technique

    Directory of Open Access Journals (Sweden)

    Roy Varghese

    2016-01-01

    Conclusion: Surgical closure of VSDs can be accomplished by placing sutures along the margins or away with comparable results. The incidence of CHB, however, seems to be less when the “excluding” technique is employed.

  10. Reduced Rate of Dehiscence After Implementation of a Standardized Fascial Closure Technique in Patients Undergoing Emergency Laparotomy

    DEFF Research Database (Denmark)

    Tolstrup, Mai-Britt; Watt, Sara Kehlet; Gögenur, Ismail

    2017-01-01

    is lacking. We aimed to investigate whether this technique would reduce the rate of dehiscence. METHODS: A standardized procedure of closing the midline laparotomy by using a "small steps" technique of continuous suturing with a slowly absorbable (polydioxanone) suture material in a wound-suture ratio...

  11. A comparative study to evaluate the effects of ligation methods on friction in sliding mechanics using 0.022" slot brackets in dry state: An In-vitro study.

    Science.gov (United States)

    Vinay, K; Venkatesh, M J; Nayak, Rabindra S; Pasha, Azam; Rajesh, M; Kumar, Pradeep

    2014-04-01

    Friction between archwires and brackets is assuming greater importance for finishing with increased use of sliding mechanics in orthodontics as friction impedes the desired tooth movement. The following study is conducted to compare and evaluate the effect of ligation on friction in sliding mechanics using 0.022" slot bracket in dry condition. In the study 48 combinations of brackets, archwires and different ligation techniques were tested in order to provide best combination that offers less friction during sliding mechanics. Instron- 4467 machine was used to evaluate static and kinetic friction force values and the results were subjected to Statistical Analysis and Anova test. The results of the study showed that 0.022" metal brackets, Stainless steel wires and Slick modules provided the optimum frictional resistance to sliding mechanics. It is observed that frictional forces of 0.019" x 0.025" were higher when compared with 0.016" x 0.022" Stainless steel archwire due to the increase in dimension. Self-ligating brackets offered least friction followed by mini twin, variable force, regular stainless steel, ceramic with metal insert bracket and ceramic brackets. The stainless steel ligature offered less resistance than slick and grey modules, and TMA wires recorded maximum friction. The stainless steel archwire of 0.019" x 0.025" dimension are preferred during sliding mechanics, these archwires with variable force brackets ligated with Slick Modules offer decreased friction and is cost effective combination which can be utilized during sliding mechanics. How to cite the article: Vinay K, Venkatesh MJ, Nayak RS, Pasha A, Rajesh M, Kumar P. A comparative study to evaluate the effects of ligation methods on friction in sliding mechanics using 0.022" slot brackets in dry state: An In-vitro study. J Int Oral Health 2014;6(2):76-83.

  12. The effect of different soft drinks on the shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Omid Khoda, M; Heravi, F; Shafaee, H; Mollahassani, H

    2012-01-01

    It is proved that acidic soft drinks that are commonly used, have an adverse effect on dental structures, and may deteriorate oral heath of our patients and orthodontic appliances. The aim of this study was to compare the effect of yoghurt drink with other soft drinks on the shear bond strength of orthodontic brackets. Seventy-five first premolar teeth extracted for orthodontic purposes were selected and standard twin metal brackets were bonded on the center of buccal surface with No-Mix composite. The teeth were thermocycled for 625 cycles and randomly divided into five groups of artificial saliva, carbonated yoghurt drink with lactic acid base, non-carbonated yoghurt drink with lactic acid base, 7 up with citric acid base and Pepsi with phosphoric acid base. In all groups, the teeth were immersed in liquid for five-minute sessions three times with equal intervening intervals for 3 months. SBS was measured by a universal testing machine with a speed of 0.5mm/min. Data was analyzed statistically by one-way ANOVA. The results showed that mean values for the shear bond strength of carbonated yoghurt drinks, non-carbonated yoghurt drinks, 7up and Pepsi groups were 12.98(±2.95), 13.26(±4.00), 16.11(±4.89), 14.73(±5.10), respectively. There was no statistically significant difference among the groups (P-value= 0.238) Soft drinks used in this study did not decrease the bond strength of the brackets bonded with this specific type of composite.

  13. The Effect of Different Soft Drinks on the Shear Bond Strength of Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    M Omid Khoda

    2012-01-01

    Full Text Available Objective: It is proved that acidic soft drinks that are commonly used, have an adverse effect on dental structures, and may deteriorate oral heath of our patients and orthodontic appliances. The aim of this study was to compare the effect of yoghurt drink with other soft drinks on the shear bond strength of orthodontic brackets.Materials and Methods: Seventy-five first premolar teeth extracted for orthodontic purposes were selected and standard twin metal brackets were bonded on the center of buccal surface with No-Mix composite. The teeth were thermocycled for 625 cycles and randomly divided into five groups of artificial saliva, carbonated yoghurt drink with lactic acid base, non-carbonated yoghurt drink with lactic acid base, 7 up with citric acid base and Pepsi with phosphoric acid base. In all groups, the teeth were immersed in liquid for five-minute sessions three times with equal intervening intervals for 3 months. SBS was measured by a universal testing machine with a speed of 0.5mm/min. Data was analyzed statistically by one-way ANOVA.Results: The results showed that mean values for the shear bond strength of carbonated yoghurt drinks, non-carbonated yoghurt drinks, 7up and Pepsi groups were 12.98(+_2.95, 13.26(+_4.00, 16.11(+_4.89, 14.73(+_5.10, respectively. There was no statistically significant difference among the groups (P-value= 0.238Conclusion: Soft drinks used in this study did not decrease the bond strength of the brackets bonded with this specific type of composite.

  14. The Influence of No-Primer Adhesives and Anchor Pylons Bracket Bases on Shear Bond Strength of Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Andrea Scribante

    2013-01-01

    Full Text Available Objective. The aim of this study was to compare the shear bond strength (SBS and adhesive remnant index (ARI scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP with different bracket bases (anchor pylons and 80-gauge mesh were bonded to the teeth using a conventional adhesive (Transbond XT and two different no-primer adhesive (Ortho Cem; Heliosit systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs, Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs.

  15. Comparative Study of Periodontal Status of Early Orthodontic Subjects treated with Self-ligating Brackets vs Conventional Edgewise Brackets

    Directory of Open Access Journals (Sweden)

    Biken Shrestha

    2014-01-01

    Conclusion: The use of SLBs or the conventionally ligated brackets have no difference in the periodontal response in early orthodontic patients. Oral hygiene prophylaxis before the start of the orthodontic treatment and its maintenance throughout the treatment duration is of prime importance.

  16. Evaluation of failure characteristics and bond strength after ceramic and polycarbonate bracket debonding : effect of bracket base silanization

    NARCIS (Netherlands)

    Ozcan, M.; Finnema, K.; Ybema, A.

    The objectives of this study were to evaluate the effect of silanization on the failure type and shear-peel bond strength (SBS) of ceramic and polycarbonate brackets, and to determine the type of failure when debonded with either a universal testing machine or orthodontic pliers. Silanized and

  17. [Abdominothoracic esophageal resection according to Ivor Lewis with intrathoracic anastomosis : standardized totally minimally invasive technique].

    Science.gov (United States)

    Runkel, N; Walz, M; Ketelhut, M

    2015-05-01

    The clinical and scientific interest in minimally invasive techniques for esophagectomy (MIE) are increasing; however, the intrathoracic esophagogastric anastomosis remains a surgical challenge and lacks standardization. Surgeons either transpose the anastomosis to the cervical region or perform hybrid thoracotomy for stapler access. This article reports technical details and early experiences with a completely laparoscopic-thoracoscopic approach for Ivor Lewis esophagectomy without additional thoracotomy. The extent of radical dissection follows clinical guidelines. Laparoscopy is performed with the patient in a beach chair position and thoracoscopy in a left lateral decubitus position using single lung ventilation. The anvil of the circular stapler is placed transorally into the esophageal stump. The specimen and gastric conduit are exteriorized through a subcostal rectus muscle split incision. The stapler body is placed into the gastric conduit and both are advanced through the abdominal mini-incision transhiatally into the right thoracic cavity, where the anastomosis is constructed. Data were collected prospectively and analyzed retrospectively. A total of 23 non-selected consecutive patients (mean age 69 years, range 46-80 years) with adenocarcinoma (n = 19) or squamous cell carcinoma (n = 4) were surgically treated between June 2010 and July 2013. Neoadjuvant therapy was performed in 15 patients resulting in 10 partial and 4 complete remissions. There were no technical complications and no conversions. Mean operative time was 305 min (range 220-441 min). The median lymph node count was 16 (range 4-42). An R0 resection was achieved in 91 % of patients and 3 anastomotic leaks occurred which were successfully managed endoscopically. There were no postoperative deaths. The intrathoracic esophagogastric anastomosis during minimally invasive Ivor Lewis esophagectomy can be constructed in a standardized fashion without an additional thoracotomy

  18. Standardization of MIP technique in three-dimensional CT portography: usefulness in evaluation of portosystemic collaterals in cirrhotic patients

    International Nuclear Information System (INIS)

    Kim, Jong Gi; Kim, Yong; Kim, Chang Won; Lee, Jun Woo; Lee, Suk Hong

    2003-01-01

    To assess the usefulness of three-dimensional CT portography using a standardized maximum intensity projection (MIP) technique for the evaluation of portosystemic collaterals in cirrhotic patients. In 25 cirrhotic patients with portosystemic collaterals, three-phase CT using a multide-tector-row helical CT scanner was performed to evaluate liver disease. Late arterial-phase images were transferred to an Advantage Windows 3.1 workstation (Gener Electric). Axial images were reconstructed by means of three-dimensional CT portography, using both a standardized and a non-standardized MIP technique, and the respective reconstruction times were determined. Three-dimensional CT portography with the standardized technique involved eight planes, namely the spleno-portal confluence axis (coronal, lordotic coronal, lordotic coronal RAO 30 .deg. C, and lordotic coronal LAO 30 .deg. C), the left renal vein axis (lordotic coronal), and axial MIP images (lower esophagus level, gastric fundus level and splenic hilum). The eight MIP images obtained in each case were interpreted by two radiologists, who reached a consensus in their evaluation. The portosystemic collaterals evaluated were as follows: left gastric vein dilatation; esophageal, paraesophageal, gastric, and splenic varix; paraumbilical vein dilatation; gastro-renal, spleno-renal, and gastro-spleno-renal shunt; mesenteric, retroperitoneal, and omental collaterals. The average reconstruction time using the non-standardized MIP technique was 11 minutes 23 seconds, and with the standardized technique, the time was 6 minutes 5 seconds. Three-dimensional CT portography with the standardized technique demonstrated left gastric vein dilatation (n=25), esophageal varix (n=18), paraesophageal varix (n=13), gastric varix (n=4), splenic varix (n=4), paraumbilical vein dilatation (n=4), gastro-renal shunt (n=3), spleno-renal shunt (n=3), and gastro-spleno-renal shunt (n=1). Using three-dimensional CT protography and the non-standardized

  19. Orthodontic brackets removal under shear and tensile bond strength resistance tests – a comparative test between light sources

    International Nuclear Information System (INIS)

    Silva, P C G; Porto-Neto, S T; Lizarelli, R F Z; Bagnato, V S

    2008-01-01

    We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 ± 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased

  20. Development, improvement and calibration of neutronic reaction rates measurements: elaboration of a standard techniques basis

    International Nuclear Information System (INIS)

    Hudelot, J.P.

    1998-06-01

    In order to improve and to validate the neutronics calculation schemes, perfecting integral measurements of neutronics parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronics reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO 2 ) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238 U (defined as the ratio of 238 U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242 Pu (on MOX rods) and 232 Th (on

  1. Self-ligating vs conventional twin brackets during en-masse space closure with sliding mechanics.

    Science.gov (United States)

    Miles, Peter G

    2007-08-01

    The aim of this study was to compare the rate of en-masse space closure with sliding mechanics between passive self-ligating SmartClip brackets (3M Unitek, Monrovia, Calif) and conventional twin brackets ligated with stainless steel ligatures. Nineteen patients including 20 arches participated in this prospective trial with 0.018-in slot brackets. All patients had first premolar extractions in at least 1 arch, with the second premolar and the first molar distal to the extraction site bonded with SmartClip brackets on 1 side and conventional twin brackets on the other. The sides were alternated with each consecutive patient. Space closure was achieved on 0.016 x 0.022-in stainless steel wires with nickel-titanium coil springs activated 6 to 9 mm. The patients were recalled every 5 weeks until 1 side had closed. The distances from the mesial aspect of the canine bracket to the distal aspect of the first molar bracket were recorded before and after space closure, and an average rate of space closure per month was calculated. Thirteen patients completed the trial (14 arches); the median rates of tooth movement for the SmartClip bracket side (1.1 mm per month) and the conventional twin bracket side (1.2 mm per month) were not significantly different (P = .86). There was no significant difference in the rate of en-masse space closure between passive SmartClip brackets and conventional twin brackets tied with stainless steel ligatures.

  2. A study to compare the effects of simulated torquing forces on pre-adjusted orthodontic brackets.

    Science.gov (United States)

    McKnight, M M; Jones, S P; Davies, E H

    1994-11-01

    The transmission of torquing forces between three types of preadjusted bracket was investigated. 0.022-inch Roth prescription 'A'-Company (stainless steel), Silkon (reinforced polycarbonate), and Allure III (polycrystalline ceramic) brackets were used. A selection of stainless steel archwires were chosen, 0.018 x 0.025, 0.019 x 0.025, and 0.021 x 0.025 inch. The brackets were torqued with respect to the archwire and force v. angular deflection was recorded on an Instron machine. The dimension of angular change was in part dependent on the ability of the bracket to elastically or plastically deform. There were no significant differences between bracket types with the 0.018 x 0.025-inch archwire. 'A'-Company brackets demonstrated a significantly lower resistance to loading compared to Silkon brackets in the 0.019 x 0.025-inch group. The greatest amount of distortion was seen in Silkon brackets with an 0.021 x 0.025-inch archwire. Allure III brackets demonstrated the greatest resistance to loading in all groups. As no apparent distortion under loading is seen in Allure III brackets, it is assumed that the load is largely transmitted to the tooth. Full thickness stainless steel rectangular wires should be avoided with these brackets, in order to prevent overloading.

  3. Finite Element Analysis Design of a Split Rotor Bracket for a Bulb Turbine Generator

    Directory of Open Access Journals (Sweden)

    Yongyao Luo

    2013-01-01

    Full Text Available The rotor bracket is a key component of the generator rotor with cracks in the rotor bracket leading to rubbing between the rotor and stator, which threatens safe operation of the unit. The rotor rim is so complicated that the equivalent radial stiffness of rim was determined by numerical simulation other than engineering experience. A comprehensive numerical method including finite element analyses and the contact method for multibody dynamics has been used to design the split rotor bracket. The com-putational results showed that cracks would occur in the initial design of the bracket when the turbine operated at the runaway speed, and the bracket design should be improved. The improved design of the bracket was strong enough to avoid cracks and rub between the rotor and stator. This design experience will help improve the design of split rotor brackets for bulb turbine generators.

  4. Standardization of pulmonary ventilation technique using volume-controlled ventilators in rats with congenital diaphragmatic hernia

    Directory of Open Access Journals (Sweden)

    Rodrigo Melo Gallindo

    Full Text Available OBJECTIVE: To standardize a technique for ventilating rat fetuses with Congenital Diaphragmatic Hernia (CDH using a volume-controlled ventilator. METHODS: Pregnant rats were divided into the following groups: a control (C; b exposed to nitrofen with CDH (CDH; and c exposed to nitrofen without CDH (N-. Fetuses of the three groups were randomly divided into the subgroups ventilated (V and non-ventilated (N-V. Fetuses were collected on day 21.5 of gestation, weighed and ventilated for 30 minutes using a volume-controlled ventilator. Then the lungs were collected for histological study. We evaluated: body weight (BW, total lung weight (TLW, left lung weight (LLW, ratios TLW / BW and LLW / BW, morphological histology of the airways and causes of failures of ventilation. RESULTS: BW, TLW, LLW, TLW / BW and LLW / BW were higher in C compared with N- (p 0.05. The morphology of the pulmonary airways showed hypoplasia in groups N- and CDH, with no difference between V and N-V (p <0.05. The C and N- groups could be successfully ventilated using a tidal volume of 75 ìl, but the failure of ventilation in the CDH group decreased only when ventilated with 50 ìl. CONCLUSION: Volume ventilation is possible in rats with CDH for a short period and does not alter fetal or lung morphology.

  5. Evaluation of friction produced by self-ligating, conventional and Barbosa Versatile brackets

    Directory of Open Access Journals (Sweden)

    Jurandir Antonio BARBOSA

    Full Text Available Abstract Introduction The Barbosa Versatile bracket design may provide lower frictional force and greater sliding. However, no in vitro studies have shown its sliding mechanisms and frictional resistance, particularly in comparison with other self-ligating or conventional brackets. Objective To compare the frictional resistance among self-ligating brackets (EasyClip/ Aditek, Damon MX/ Ormco and In Ovation R/ GAC; conventional brackets (Balance Roth/ GAC, and Roth Monobloc/ Morelli; and Barbosa Versatile bracket (Barbosa Versatile/ GAC with different angles and arch wires. Material and method Brackets were tested with the 0.014", 0.018", 0.019"×0.025" and 0.021"×0.025" stainless steel wires, with 0, 5, 10, 15 and 20 degree angulations. Tying was performed with elastomeric ligature for conventional and Barbosa Versatile brackets, or with a built-in clip system of the self-ligating brackets. A universal testing machine was used to obtain sliding strength and friction value readouts between brackets and wires. Result Three-way factorial ANOVA 4×5×6 (brackets × angulation × wire and Tukey tests showed statistically significant differences for all factors and all interactions (p<0.0001. Static frictional resistance showed a lower rate for Barbosa Versatile bracket and higher rates for Roth Monobloc and Balance brackets. Conclusion The lowest frictional resistance was obtained with the Barbosa Versatile bracket and self-ligating brackets in comparison with the conventional type. Increasing the diameter of the wires increased the frictional resistance. Smaller angles produced less frictional resistance.

  6. Frictional and mechanical properties of diamond-like carbon-coated orthodontic brackets.

    Science.gov (United States)

    Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Nakagaki, Susumu; Endo, Kazuhiko; Mizoguchi, Itaru

    2013-04-01

    This study investigated the effects of a diamond-like carbon (DLC) coating on frictional and mechanical properties of orthodontic brackets. DLC films were deposited on stainless steel brackets using the plasma-based ion implantation/deposition (PBIID) method under two different atmospheric conditions. As-received metal brackets served as the control. Two sizes of stainless steel archwires, 0.018 inch diameter and 0.017 × 0.025 inch cross-section dimensions, were used for measuring static and kinetic friction by drawing the archwires through the bracket slots, using a mechanical testing machine (n = 10). The DLC-coated brackets were observed with a scanning electron microscope (SEM). Values of hardness and elastic modulus were obtained by nanoindentation testing (n = 10). Friction forces were compared by one-way analysis of variance and the Scheffé test. The hardness and elastic modulus of the brackets were compared using Kruskal-Wallis and Mann-Whitney U-tests. SEM photomicrographs showed DLC layers on the bracket surfaces with thickness of approximately 5-7 μm. DLC-coated brackets deposited under condition 2 showed significantly less static frictional force for the stainless steel wire with 0.017 × 0.025 inch cross-section dimensions than as-received brackets and DLC-coated brackets deposited under condition 1, although both DLC-coated brackets showed significantly less kinetic frictional force than as-received brackets. The hardness of the DLC layers was much higher than that of the as-received bracket surfaces. In conclusion, the surfaces of metal brackets can be successfully modified by the PBIID method to create a DLC layer, and the DLC-coating process significantly reduces frictional forces.

  7. An in vivo Study on Bacterial Colonization with Metal, Ceramic and Self-ligating Brackets: A Scanning Electron Microscopy Study

    Directory of Open Access Journals (Sweden)

    Aravind S Raju

    2013-01-01

    Conclusion: This study highlights that higher retention of plaque in ceramic brackets ligated with elastomeric ring followed with metal brackets ligated with steel ligatures and comparatively less plaque retention in self-ligating brackets. Excess composite around the bracket base is the critical site of plaque accumulation associated with fixed appliances due to its rough surface texture.

  8. Coordinating bracket torque and incisor inclination : Part 2: Reproducibility and statistical measures of the torque coordination angle (TCA).

    Science.gov (United States)

    Sino, H; Zimmer, B; Schelper, I; Schenk-Kazan, S; Streibelt, F

    2018-03-09

    To determine the reproducibility and statistical measures of the torque coordination angle (TCA). A total of 107 final cephalograms and corresponding casts were included, all reflecting treatment outcomes that met high qualitative standards, one of them being a Peer Assessment Rating (PAR) score of ≤3. Based on these records, the TCA was measured as a parameter to identify differences related to tooth morphology and bracket position between the torque-relevant reference plane at the bracket base and the long axis of a tooth. All measurements were performed on upper and lower central incisors (U1 and L1). Several reproducibility assessments for the TCA measurements yielded good results, including objectivity at 1.26 ± 0.81° (U1) or 1.41 ± 1.18° (L1), examiner reliability at 1.30 ± 0.97° (U1) or 1.25 ± 0.82° (L1), and method reliability at 1.80 ± 1.13° (U1) or 1.53 ± 1.07° (L1). The statistical measures revealed a high degree of interindividual variability. With bracket placement 4.5 mm (U1) or 4.0 mm (L1) above the incisal edge, the differences between the maximum and minimum TCA values were similarly large in both jaws (21.0° for U1 or 20.0° for L1), given mean TCA values of 24.6 ± 3.6° (U1) or 22.9 ± 4.3° (L1). Moving the bracket placement from 3.5 to 5.5 mm (U1) or from 3.0 to 5.0 mm (L1) changed the mean TCA values by 4.5° (U1) or 3.2° (L1). The TCA is a suitable cephalometric parameter to identify differences related to tooth morphology and bracket placement. Given its high interindividual variability, the fixed torque value of a specific bracket system should not be expected to produce the same incisor inclinations across patients.

  9. 𝒩 = 2 supersymmetric harmonic oscillator: Basic brackets without canonical conjugate momenta

    Science.gov (United States)

    Srinivas, N.; Shukla, A.; Malik, R. P.

    2015-09-01

    We exploit the ideas of spin-statistics theorem, normal-ordering and the key concepts behind the symmetry principles to derive the canonical (anti)commutators for the case of a one (0 + 1)-dimensional (1D) 𝒩 = 2 supersymmetric (SUSY) harmonic oscillator (HO) without taking the help of the mathematical definition of canonical conjugate momenta with respect to the bosonic and fermionic variables of this toy model for the Hodge theory (where the continuous and discrete symmetries of the theory provide the physical realizations of the de Rham cohomological operators of differential geometry). In our present endeavor, it is the full set of continuous symmetries and their corresponding generators that lead to the derivation of basic (anti)commutators amongst the creation and annihilation operators that appear in the normal mode expansions of the dynamical fermionic and bosonic variables of our present 𝒩 = 2 SUSY theory of a HO. These basic brackets are in complete agreement with such kind of brackets that are derived from the standard canonical method of quantization scheme.

  10. Modification of the cranial closing wedge ostectomy technique for the treatment of canine cruciate disease. Description and comparison with standard technique.

    Science.gov (United States)

    Wallace, A M; Addison, E S; Smith, B A; Radke, H; Hobbs, S J

    2011-01-01

    To describe a modification of the cranial closing wedge ostectomy (CCWO) technique and to compare its efficacy to the standard technique on cadaveric specimens. The standard and modified CCWO technique were applied to eight pairs of cadaveric tibiae. The following parameters were compared following the ostectomy: degrees of plateau levelling achieved (degrees), tibial long axis shift (degrees), reduction in tibial length (mm), area of bone wedge removed (cm²), and the area of proximal fragment (cm²). The size of the removed wedge of bone and the reduction in tibial length were significantly less with the modified CCWO technique. The modified CCWO has two main advantages. Firstly a smaller wedge is removed, allowing a greater preservation of bone stock in the proximal tibia, which is advantageous for implant placement. Secondly, the tibia is shortened to a lesser degree, which might reduce the risk of recurvatum, fibular fracture and patella desmitis. These factors are particularly propitious for the application of this technique to Terrier breeds with excessive tibial plateau angle, where large angular corrections are required. The modified CCWO is equally effective for plateau levelling and results in an equivalent tibial long-axis shift. A disadvantage with the modified technique is that not all of the cross sectional area of the distal fragment contributes to load sharing at the osteotomy.

  11. Algebric generalization of symmetry Dirac bracket. Application to field theory

    International Nuclear Information System (INIS)

    Rocha Filho, T.M. da.

    1987-01-01

    The A set of observable of a physical system with finite e infinite number of degrees of freedom and submitted to certain constraint conditions, is considered. Using jordan algebra structure on A in relation to bymmetric Poisson bracket obtained by Droz-Vincent, a jordan product is obtained on the A/I quocient set with regard to I ideal generated by constraints of second class. It is shown that this product on A/I corresponds to symmetric Dirac bracket. The developed formulation is applied to a system corresponding to harmonic oscillators, non relativistic field, Rarita-Schwinger field and the possibility of its utilization in fermionic string theories is discussed. (M.C.K.)

  12. A quantum Goldman bracket in (2 + 1) quantum gravity

    International Nuclear Information System (INIS)

    Nelson, J E; Picken, R F

    2008-01-01

    In the context of quantum gravity for spacetimes of dimension (2 + 1), we describe progress in the construction of a quantum Goldman bracket for intersecting loops on surfaces. Using piecewise linear paths in R 2 (representing loops on the spatial manifold, i.e. the torus) and a quantum connection with noncommuting components, we review how holonomies and Wilson loops for two homotopic paths are related by phases in terms of the signed area between them. Paths rerouted at intersection points with other paths occur on the rhs of the Goldman bracket. To better understand their nature we introduce the concept of integer points inside the parallelogram spanned by two intersecting paths, and show that the rerouted paths must necessarily pass through these integer points

  13. Derivation of the Hall and extended magnetohydrodynamics brackets

    Energy Technology Data Exchange (ETDEWEB)

    D' Avignon, Eric C., E-mail: cavell@physics.utexas.edu; Morrison, Philip J., E-mail: morrison@physics.utexas.edu [Department of Physics and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States); Lingam, Manasvi, E-mail: mlingam@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-06-15

    There are several plasma models intermediate in complexity between ideal magnetohydrodynamics (MHD) and two-fluid theory, with Hall and Extended MHD being two important examples. In this paper, we investigate several aspects of these theories, with the ultimate goal of deriving the noncanonical Poisson brackets used in their Hamiltonian formulations. We present fully Lagrangian actions for each, as opposed to the fully Eulerian, or mixed Eulerian-Lagrangian, actions that have appeared previously. As an important step in this process, we exhibit each theory's two advected fluxes (in analogy to ideal MHD's advected magnetic flux), discovering also that with the correct choice of gauge they have corresponding Lie-dragged potentials resembling the electromagnetic vector potential, and associated conserved helicities. Finally, using the Euler-Lagrange map, we show how to derive the noncanonical Eulerian brackets from canonical Lagrangian ones.

  14. Orthodontic bracket bonding to glazed full-contour zirconia

    Directory of Open Access Journals (Sweden)

    Ji-Young Kwak

    2016-05-01

    Full Text Available Objectives This study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces. Materials and Methods Glazed zirconia (except for the control, Zirkonzahn Prettau disc surfaces were pre-treated: PO (control, polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z or a silane primer (Monobond-S, S was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S. Metal bracket-bonded specimens were stored in water for 24 hr at 37℃, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10. Results Except for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z (4.60 ± 1.08 MPa and all other groups (13.38 ± 2.57 - 15.78 ± 2.39 MPa, p < 0.05. For AA-Z, most of the adhesive remained on the bracket. Conclusions For bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed.

  15. Enamel Resistance to Demineralization After Bracket Debonding Using Fluoride Varnish

    OpenAIRE

    Vicente, Ascensión; Ortiz Ruiz, Antonio José; García López, Miriam; Martínez Beneyto, Yolanda; Bravo-González, Luis-Alberto

    2017-01-01

    The aim of this study was to evaluate the elemental content and morphology of enamel subjected to demineralization cycles after bracket debonding, adhesive remnant removal, and application of a fluoride varnish. 125 bovine teeth were divided into five groups (n = 25): 1) Intact enamel; 2) Intact enamel + demineralization cycles (DC); 3) Enamel after adhesive removal; 4)Enamel after adhesive removal + DC; 5) Enamel after adhesive removal + Profluorid + DC. The weight percentages of calcium (Ca...

  16. Standardization of the PCR technique for the detection of delta toxin in Staphylococcus spp.

    Directory of Open Access Journals (Sweden)

    C. Marconi

    2005-06-01

    Full Text Available Coagulase-negative staphylococci (CNS, components of the normal flora of neonates, have emerged as important opportunistic pathogens of nosocomial infections that occur in neonatal intensive care units. Some authors have reported the ability of some CNS strains, particularly Staphylococcus epidermidis, to produce a toxin similar to S. aureus delta toxin. This toxin is an exoprotein that has a detergent action on the membranes of various cell types resulting in rapid cell lysis. The objectives of the present study were to standardize the Polymerase Chain Reaction (PCR technique for the detection of the gene responsible for the production of delta toxin (hld gene in staphylococcal species isolated from catheters and blood cultures obtained from neonates, and to compare the results to those obtained with the phenotypic synergistic hemolysis method. Detection of delta toxin by the phenotypic and genotypic method yielded similar results for the S. aureus isolates. However, in S. epidermidis, a higher positivity was observed for PCR (97.4% compared to the synergistic hemolysis method (86.8%. Among CNS, S. epidermidis was the most frequent isolate and was a delta toxin producer. Staphylococcus simulans and S. warneri tested positive by the phenotypic method, but their positivity was not confirmed by PCR for the hld gene detection. These results indicate that different genes might be responsible for the production of this toxin in different CNS species, requiring highly specific primers for their detection. PCR was found to be a rapid and reliable method for the detection of the hld gene in S. aureus and S. epidermidis.

  17. "Heidelberg standard examination" and "Heidelberg standard procedures" - Development of faculty-wide standards for physical examination techniques and clinical procedures in undergraduate medical education.

    Science.gov (United States)

    Nikendei, C; Ganschow, P; Groener, J B; Huwendiek, S; Köchel, A; Köhl-Hackert, N; Pjontek, R; Rodrian, J; Scheibe, F; Stadler, A-K; Steiner, T; Stiepak, J; Tabatabai, J; Utz, A; Kadmon, M

    2016-01-01

    The competent physical examination of patients and the safe and professional implementation of clinical procedures constitute essential components of medical practice in nearly all areas of medicine. The central objective of the projects "Heidelberg standard examination" and "Heidelberg standard procedures", which were initiated by students, was to establish uniform interdisciplinary standards for physical examination and clinical procedures, and to distribute them in coordination with all clinical disciplines at the Heidelberg University Hospital. The presented project report illuminates the background of the initiative and its methodological implementation. Moreover, it describes the multimedia documentation in the form of pocketbooks and a multimedia internet-based platform, as well as the integration into the curriculum. The project presentation aims to provide orientation and action guidelines to facilitate similar processes in other faculties.

  18. Precision of indirect bonding of lingual brackets using the Quick Modul System (QMS)®.

    Science.gov (United States)

    Schubert, Katharina; Halbich, Thomas; Jost-Brinkmann, Paul-Georg; Müller-Hartwich, Ralf

    2013-01-01

    Almost all common laboratory procedures for lingual orthodontic appliances use indirect bonding of brackets via transfer trays. Ensuring precise transfer of these bracket positions to the oral cavity is especially important, as subsequent manual adjustments are challenging in lingual orthodontics and even minor errors of bracket placement may result in considerably deviating tooth positions. The purpose of this study was to evaluate in vivo the precision of indirect bonding of lingual brackets using the "Quick Modul System" (QMS®; Halbich Lingualtechnik, Berlin, Germany). The study included eight consecutive patients treated with lingual brackets. After placing the brackets on a setup cast, the resultant positions were digitized with an optical scanner (OraScanner®; OraMetrix, Richardson, TX, USA). Individual transfer copings (QMS®) were used to transfer the brackets to the mouth, followed by intraoral scanning and virtual superimposition to analyze how much the intraoral bracket positions deviated from the positions on the cast. Translational deviations added up to a mean transfer error of 0.12 mm in the mesiodistal, 0.13 mm in the orovestibular, and 0.10 mm in the vertical planes. Mean deviations in rotational directions amounted to 2.20° of inclination, 3.21° of angulation, and 2.29° of rotation. The transfer system investigated in this study is capable of transferring bracket positions with good clinical precision. No differences between the bracket types and both modifications of the transfer copings were noted.

  19. [Bond strengths of customized titanium brackets manufactured by selective laser melting].

    Science.gov (United States)

    Zou, Dao-xing; Wang, Ze-min; Guo, Hong-ming; Li, Song; Bai, Yu-xing

    2013-07-01

    To investigate the bond strengths of customized titanium bracket manufactured by selective laser melting. Eighty human premolars which had been extracted for orthodontic purpose were collected and divided randomly (by random table) into two groups (customized bracket group and 3M bracket group, 40 molars in each group). The 35% phosphoric acid was used for etching and the brackets were bonded with 3M Unitek bonding adhesive. All bonded specimens were placed in saline for 24 hours at room temperature and were tested on DWD3050 electronic testing machine to determine the shear bond strength and tensile bond strength. After debonding, the adhesive remnant indexes (ARI) were recorded. The shear bond strengths of customized brackets was 6.80 (6.20, 8.32) MPa, which was significantly lower than that of the 3M brackets [10.46 (9.72, 11.48) MPa] (Z = -3.463, P < 0.05). And the tensile bond strengths of customized brackets was (6.93 ± 1.21) MPa, which was significantly higher than that of the 3M brackets [(5.88 ± 1.23) MPa] (t = 2.81, P < 0.05). No significant difference was found in the ARI between two different kinds of the brackets. The shear bond strength and tensile bond strength of both kinds of brackets were enough for clinic application.

  20. Comparison of anthropometry with photogrammetry based on a standardized clinical photographic technique using a cephalostat and chair.

    Science.gov (United States)

    Han, Kihwan; Kwon, Hyuk Joon; Choi, Tae Hyun; Kim, Jun Hyung; Son, Daegu

    2010-03-01

    The aim of this study was to standardize clinical photogrammetric techniques, and to compare anthropometry with photogrammetry. To standardize clinical photography, we have developed a photographic cephalostat and chair. We investigated the repeatability of the standardized clinical photogrammetric technique. Then, with 40 landmarks, a total of 96 anthropometric measurement items was obtained from 100 Koreans. Ninety six photogrammetric measurements from the same subjects were also obtained from standardized clinical photographs using Adobe Photoshop version 7.0 (Adobe Systems Corporation, San Jose, CA, USA). The photogrammetric and anthropometric measurement data (mm, degree) were then compared. A coefficient was obtained by dividing the anthropometric measurements by the photogrammetric measurements. The repeatability of the standardized photography was statistically significantly high (p=0.463). Among the 96 measurement items, 44 items were reliable; for these items the photogrammetric measurements were not different to the anthropometric measurements. The remaining 52 items must be classified as unreliable. By developing a photographic cephalostat and chair, we have standardized clinical photogrammetric techniques. The reliable set of measurement items can be used as anthropometric measurements. For unreliable measurement items, applying a suitable coefficient to the photogrammetric measurement allows the anthropometric measurement to be obtained indirectly.

  1. Comparative study between random vibration and linear static analysis using Miles method for thruster brackets in space structures

    Directory of Open Access Journals (Sweden)

    Ion DIMA

    2017-06-01

    Full Text Available Random vibrations occur during the launch at the fastening interface between thruster brackets and basic support of satellite. These are generated in the launcher by the motion of some mechanical parts, combustion phenomena or structural elements excited by the acoustic environment. The goal of this comparative study is to find a simplified and efficient validation method using FEM PATRAN-NASTRAN software for thruster brackets in the random vibrations environment for space applications. The random vibration analysis requests complex pre/ post processing efforts and large hardware resources for various geometrical shapes. The PATRAN-NASTRAN random vibration analysis consists of frequency response analysis (111 solver and Acceleration Spectral Density (ASD diagram, taking into account the natural frequencies of the bracket. The Miles method computes the root mean square acceleration (aRMS using the natural frequencies and the ASD diagram as input. As a conservative hypothesis in the random analysis, the three sigma standard deviation criteria in normal Gaussian distribution is applied at these RMS acceleration values, which means to multiply the aRMS by a load factor of three. Simplified method consists of using linear static PATRAN-NASTRAN analysis (101 solver where the aRMS are introduced as loads. For validation of the simplified method, a comparative study was made between the random vibration and the linear static analysis. The final results are presented in detail in this article.

  2. Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques. 1.1.1 Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy. 1.1.2 Standard comparison technique using pure gold, or gold-aluminum alloy, and 1.1.3 Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy. 1.2 The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-...

  3. [Health protection for rural workers: the need to standardize techniques for quantifying dermal exposure to pesticides].

    Science.gov (United States)

    Selmi, Giuliana da Fontoura Rodrigues; Trapé, Angelo Zanaga

    2014-05-01

    Quantification of dermal exposure to pesticides in rural workers, used in risk assessment, can be performed with different techniques such as patches or whole body evaluation. However, the wide variety of methods can jeopardize the process by producing disparate results, depending on the principles in sample collection. A critical review was thus performed on the main techniques for quantifying dermal exposure, calling attention to this issue and the need to establish a single methodology for quantification of dermal exposure in rural workers. Such harmonization of different techniques should help achieve safer and healthier working conditions. Techniques that can provide reliable exposure data are an essential first step towards avoiding harm to workers' health.

  4. Standard techniques for presentation and analysis of crater size-frequency data. [on moon and planetary surfaces

    Science.gov (United States)

    Arvidson, R.; Boyce, J.; Chapman, C.; Cintala, M.; Fulchignoni, M.; Moore, H.; Soderblom, L.; Neukum, G.; Schultz, P.; Strom, R.

    1979-01-01

    In September 1977 a crater studies workshop was held for the purpose of developing standardized data analysis and presentation techniques. The present report contains the unanimous recommendations of the participants. Recommendations are devoted primarily to crater size-frequency data and refer to cumulative and relative size-frequency distribution plots and to morphological analysis.

  5. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  6. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    DEFF Research Database (Denmark)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-01-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal...

  7. [Comparison study on polymerase chain reaction (PCR) and standard culture technique in detecting mycobacterium tuberculosis to diagnose of joint tuberculosis].

    Science.gov (United States)

    Sun, Yong-sheng; Wen, Jian-min; Lü, Wei-xin; Lou, Si-quan; Jiao, Chang-geng; Yang, Su-min; Xu, Hai-bin; Duan, Yong-zhuang

    2009-07-01

    To study the role of PCR technique in detection of mycobacterium tuberculosis in the samples from joint tuberculosis, and to evaluate the clinical value of PCR in diagnosis of joint tuberculosis. From June 1993 to August 2001, PCR was used to detect DNA of mycobacterium tuberculosis, and the standard culture was applied to detect mycobacterium tuberculosis. Mycobacterium tuberculosis were respectively blindly by the two techniques in the samples obtained from 95 patients with joint tuberculosis (55 males and 40 females, the age ranging from 2 to 75 years, with an average of 34 years). The positive rate of mycobacterium tuberculosis detection was calculated. In the detection of mycobacterium tuberculosis, positive rate was 82% (78/95) in PCR technique, and 16% (15/95) in standard culture technique. There were statistical differences between the two groups (chi2=67, Ptechnique is a rapid, simple, sensitive and specific method for detection of mycobacterium tuberculosis in the samples of joint tuberculosis, showing more marked advantages than the standard culture technique. It is valuable in the early rapid diagnosis and differential diagnosis of joint tuberculosis.

  8. Concurrent engineering solution for the design of ship and offshore bracket parts and fabrication process

    Directory of Open Access Journals (Sweden)

    Tae-Won Kim

    2013-09-01

    Full Text Available Brackets in ships and offshore structures are added structures that can endure stress concentrations. In this study, a concurrent engineering solution was proposed, and a high strength low carbon cast steel alloy applicable to offshore structures was designed and developed. The yield strength and ultimate tensile strength of the designed steel were 480 and 600 MPa, respectively. The carbon equivalent of the steel was 0.446 with a weld crack susceptibility index of 0.219. The optimal structural design of the brackets for offshore structures was evaluated using ANSYS commercial software. The possibility of replacing an assembly of conventional built-up brackets with a single casting bulb bracket was verified. The casting process was simulated using MAGMAsoft commercial software, and a casting fabrication process was designed. For the proposed bulb bracket, it was possible to reduce the size and weight by approximately 30% and 50%, respectively, compared to the conventional type of bracket.

  9. A comparative study of frictional resistance and surface roughness between orthodontic bracket and arch wire

    OpenAIRE

    Kazuro, SATOH; Masaru, ISHIGAME; Yukiko, NAKAMURA; Kazushi, OGASAWARA; Shigeru, TANAKA; Hiroyuki, MIURA; Department of Orthodontics, School of Dentistry, Iwate Medical University; Department of Orthodontics, School of Dentistry, Iwate Medical University; Department of Orthodontics, School of Dentistry, Iwate Medical University; Department of Orthodontics, School of Dentistry, Iwate Medical University; Department of Orthodontics, School of Dentistry, Iwate Medical University; Department of Orthodontics, School of Dentistry, Iwate Medical University

    2003-01-01

    The frictional resistance between an orthodontic bracket and arch wire is closely related to the efficiency of tooth movement in sliding mechanics. Frictional resistance may arise from the materials, geometrical configuration between the orthodontic bracket and arch wire, ligation system and its force, wire stiffness, direction and degree of orthodontic force, and surface roughness of bracket and wire. This study examined the relationship between the frictional resistance and surface roughnes...

  10. A simplified indirect bonding technique

    Directory of Open Access Journals (Sweden)

    Radha Katiyar

    2014-01-01

    Full Text Available With the advent of lingual orthodontics, indirect bonding technique has become an integral part of practice. It involves placement of brackets initially on the models and then their transfer to teeth with the help of transfer trays. Problems encountered with current indirect bonding techniques used are (1 the possibility of adhesive flash remaining around the base of the brackets which requires removal (2 longer time required for the adhesive to gain enough bond strength for secure tray removal. The new simplified indirect bonding technique presented here overcomes both these problems.

  11. Model Standards and Techniques for Control of Radon in New Residential Buildings

    Science.gov (United States)

    This document is intended to serve as a model for use to develop and adopt building codes, appendices to codes, or standards specifically applicable to unique local or regional radon control requirements.

  12. A comparative computed tomographic evaluation of expression of angulation and inclination in self ligating brackets

    Directory of Open Access Journals (Sweden)

    Rehana Bashir

    2018-01-01

    Full Text Available Introduction: An important objective of orthodontic treatment is to obtain the correct angulation and inclination for all the teeth. Very few studies have been conducted so far comparing the expression of angulation and inclination in conventional and self-ligating brackets (SLBs. The present study was designed to evaluate and compare the inclination and angulation in conventional brackets and active and passive SLBs. Materials and Methods: Totally 21 patients who required four 1st premolar extractions were selected and were randomly allotted to three groups: Group 1: Conventional Brackets (3M Unitek MBT (mean age 19.14 ± 2.12 years, Group 2: Passive Brackets (Smart Clip Brackets-3M Unitek MBT (mean age 19.71 ± 1.80 years, Group 3: Active Brackets (Empower Brackets-American Orthodontics MBT (mean age 18.29 ± 2.29 years computed tomographic records were collected before the start of treatment, after leveling and aligning and at 6 months into retraction. Results: The data were evaluated using SPSS version 16.0 using one-way ANOVA and post hoc Bonferroni tests. There was no statistically significant difference in the expression of angulation and inclination in conventional, active, and passive SLB systems. Conclusion: Self-ligating brackets seem to be no better than conventional brackets when it comes to the expression of angulation and inclination.

  13. Forces in the presence of ceramic versus stainless steel brackets with unconventional vs conventional ligatures.

    Science.gov (United States)

    Baccetti, Tiziano; Franchi, Lorenzo; Camporesi, Matteo

    2008-01-01

    To compare the forces resulting from four types of bracket/ligature combinations: ceramic brackets and stainless steel brackets combined with unconventional elastomeric ligatures (UEL) and conventional elastomeric ligatures (CEL) during the leveling and aligning phases of orthodontic therapy. The testing model consisted of five 0.022-inch preadjusted brackets (second premolar, first premolar, canine, lateral incisor, and central incisor) for each of the two bracket types. The canine bracket was welded to a sliding bar that allowed for different amounts of offset in the gingival direction. The forces generated by a 0.014-inch superelastic nickel titanium wire in the presence of either the UEL or CEL bracket/ligature systems at different amounts of upward canine misalignment (1.5 mm, 3 mm, 4.5 mm, and 6 mm) were recorded. Significant differences were found between UEL and CEL systems for all tested variables (P < .01) with the exception of the canine misalignment of 1.5 mm. The average amount of recorded force in the presence of CEL was negligible with 3.0 mm or greater of canine misalignment. On the contrary, during alignment, a force available for tooth movement was recorded in the presence of both ceramic and stainless steel brackets when associated with UEL. The type of ligature used influenced the actual amount of force released by the orthodontic system significantly more than the type of bracket used (stainless steel vs ceramic).

  14. Microleakage under metallic and ceramic brackets bonded with orthodontic self-etching primer systems.

    Science.gov (United States)

    Uysal, Tancan; Ulker, Mustafa; Ramoglu, Sabri Ilhan; Ertas, Huseyin

    2008-11-01

    To compare the in vitro microleakage of orthodontic brackets (metal and ceramic) between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides produced by self-etching primer system with that of conventional acid etching and bonding. Sixty freshly extracted human mandibular premolar teeth were used in this study. The teeth were separated into four groups of 15 teeth each and received the following treatments: Group 1, 37% phosphoric acid gel + Transbond XT liquid primer + stainless steel bracket; Group 2, Transbond Plus Self-Etching Primer (TSEP) + stainless steel bracket; Group 3, 37% phosphoric acid gel + Transbond XT liquid primer + ceramic bracket; Group 4, TSEP + ceramic bracket. After curing, specimens were further sealed with nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. The gingival sides in all groups exhibited higher microleakage scores compared with those observed in occlusal sides for both adhesive interfaces. Enamel-adhesive interfaces exhibited more microleakage than did the adhesive-bracket interfaces. Brackets bonded with self-etching primer system showed significantly higher microleakage at the enamel-adhesive interface of the gingival side. TSEP causes more microleakage between enamel-adhesive interfaces, which may lead to lower bond strength and/or white-spot lesions.

  15. Comparison surface characteristics and chemical composition of conventional metallic and Nickel-Free brackets

    Directory of Open Access Journals (Sweden)

    Ricardo Lima SHINTCOVSK

    2015-01-01

    Full Text Available This study aims at comparing conventional and nickel-free metal bracket surface characteristics with elemental composition by scanning electron microscopy (SEM, using energy dispersive spectroscopy (EDS. The sample consisted of 40 lower incisor brackets divided into four groups: ABZ = conventional brackets, Kirium Abzil 3M® (n = 10; RL = conventional brackets, Roth Light Morelli® (n = 10; NF = nickel-free brackets, Nickel-Free Morelli® (n = 10; and RM = nickel-free brackets, Roth Max Morelli® (n = 10. Qualitative evaluation of the bracket surface was performed using SEM, whereby surface features were described and compared. The elemental composition was analyzed by EDS. According to surface analysis,groups ABZ and RL showed a homogeneous surface, with better finishing, whereas the surfaces in groups NF and RM were rougher. The chemical components with the highest percentage were Fe, Cr and C. Groups NF and MR showed no nickel in their composition. In conclusion, the bracket surface of the ABZ and RL groups was more homogeneous, with grooves and pores, whereas the surfaces in groups NF and RM showed numerous flaws, cracks, pores and grooves. The chemical composition analysis confirmed that the nickel-free brackets had no Ni in their composition, as confirmed by the manufacturer’s specifications, and were therefore safe to use in patients with a medical history of allergy to this metal.

  16. Measurement of friction forces between stainless steel wires and "reduced-friction" self-ligating brackets.

    Science.gov (United States)

    Reznikov, Natalie; Har-Zion, Gilad; Barkana, Idit; Abed, Yossi; Redlich, Meir

    2010-09-01

    In this study, we assessed the friction forces between various self-ligating brackets and stainless steel orthodontic wires, subjected to different shear and bending forces in the buccolingual plane. Three kinds of self-ligating brackets and 2 kinds of ligated controls were tested in a newly developed in-vitro system. Friction was tested with stainless steel orthodontic wire in 3 deflection states. The Bonferroni multiple comparisons test was applied to evaluate intergroup differences (P friction resistance in response to wire deflection. In nonzero buccolingual deflections, passive self-ligating brackets developed higher friction forces, comparable with those in the conventional elastic ligation control group. The control brackets with reduced friction ligature had considerably lower friction forces than any other group. The active self-ligating bracket ranked between the self-ligating brackets and the reduced friction ligature group. A tribologic survey showed substantial surface alterations among wire samples coupled with passive self-ligating brackets. In contrast to manufacturers' claims, this study illustrates that, in certain clinical situations, a firm passive bracket clip can have a negative influence on the wire-bracket frictional characteristics. 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  17. Torsional strength of computer-aided design/computer-aided manufacturing-fabricated esthetic orthodontic brackets.

    Science.gov (United States)

    Alrejaye, Najla; Pober, Richard; Giordano Ii, Russell

    2017-01-01

    To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion. Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC). The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P 3467 g.mm for Mark II to 11,902 g.mm for YZ. The mean torsion angles at failure ranged from 15.3° to 40.9°. Zirconia had the highest torsional strength among the tested esthetic brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.

  18. Evaluation of the overlapping of posterior teeth in two techniques of improved interproximal panoramic program and standard panoramic

    Directory of Open Access Journals (Sweden)

    Goodarzi pour D

    2010-06-01

    Full Text Available "nBackground and Aims: Overlapping of the proximal surfaces of posterior teeth in the panoramic radiography is a major concern. Therefore, an option has been developed in the panoramic unit of Planmeca Promax, namely improved interproximal mode. This mode causes lower horizental angle with the teeth contact region during the unit rotation decreasing overlapping of the panoramic images of the posterior teeth especially premolar teeth. The present study was done to compare the overlapping of posterior teeth using two techniques of improved interproximal panoramic program and standard panoramic. "nMaterials and Methods: In this diagnostic study, 32 patients requiring panoramic radiographies at their posterior teeth during their routine diagnosis and treatment process with the mean age of 27.3 years were participated. No patients showed crowding of posterior teeth or missed and restored posterior teeth. The participants' panoramic radiographies were randomly taken by two techniques of improved interproximal panoramic and standard panoramic using Planmeca Promax device. The overlapping of the panoramic images was blindly assessed by an oral radiologist. The overlapping in both techniques was reported by frequency and percentage. The comparisons were done by Chi-square test between two techniques and the odds ratio of overlapping was estimated using regression analysis. "nResults: In standard panoramic techniques, 38.5% (148 contacts of 384 contacts of the proximal surfaces overlapped while the overlapping of the proximal surfaces was observed in 18.8% (72 contacts of 384 overall contacts in improved interproximal technique. Significant differences were noted between two techniques regarding overlapping (P<0.001. Also 66.4% and 39.1% of 4-5 teeth contacts overlapped in standard and improved techniques. The values were reported to be 39.1% and 12.5% in contacts of 5-6 teeth and 10.2% and 4.7% in the contacts of 6-7 teeth in both techniques

  19. Plaque Index in Multi-Bracket Fixed Appliances

    International Nuclear Information System (INIS)

    Rahim, Z.H.; Shaikh, S.; Razak, F.A.

    2014-01-01

    To compare the plaque index in patients receiving multi-bracket fixed orthodontic treatment for various factors like age, gender, socio-economic status, brushing practices, meal habits, types of brackets, types of ligations, use of mouthwash and duration of treatment. Study Design: Cross-sectional analytical study. Place and Duration of Study: Orthodontics Clinic, The Aga Khan University Hospital, from September to November 2011. Methodology: Socio-demographic and clinical modalities were defined and recorded for 131 patients having multi-bracket fixed appliances. The plaque index of subjects were recorded according to the Silness and Loe plaque index method. Independent sample t-test was used to see difference in plaque index in factors having two variables. One way ANOVA and Post-Hoc Tukey tests were used to see difference in plaque index in factors having three variables. Kappa statistics was used to assess inter examiner reliability. P-value 0.05 was taken to be significant. Results: The sample comprised of 37% males (n = 48) and 63% females (n = 83). The plaque index had statistically significant association with practice of brushing i.e., timing of brushing (p=0.001), method of brushing (p=0.08), type of ligatures (p=0.05) and frequency of visits (p=0.01). Conclusion: The plaque accumulation is significantly decreased in subjects who brush the teeth twice or more than twice a day and those who brush their teeth after breakfast. The use of interdental brush and stainless steel ligatures had significantly low plaque. Subjects presenting with more frequent appointments of short-period had significantly less plaque. (author)

  20. Remnant preservation in anterior cruciate ligament reconstruction versus standard techniques: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Ma, Tianjun; Zeng, Chun; Pan, Jianying; Zhao, Chang; Fang, Hang; Cai, Daozhang

    2017-01-01

    Preserving the remnant during anterior cruciate ligament (ACL) reconstruction is considered beneficial for graft healing, but it might increase the technical difficulties and complications. This study was to compare outcomes of using the technique of remnant preservation during the ACL reconstruction versus the standard procedure with the debridement of remnant. We searched PubMed and EMBASE and the Cochrane Library for randomized controlled trials comparing the outcomes of ACL reconstruction both with and without remnant preservation. The risk of bias was assessed in accordance with the Cochrane Collaboration's risk of bias tool. Meta-analysis was performed to compare results. Six randomized controlled trials with 346 patients were included. Statistically significant differences in favor of using technique of remnant preservation were observed for Lysholm Score, arthrometer measurements, and tibial tunnel enlargement. There was no significant difference between remnant technique of preservation and the standard procedure with respect to the IKDC (International Knee Documentation Committee) grade, IKDC score, Lachman Test, Pivot-shift Test, range of motion (ROM), and the incidence of the cyclops lesion. This meta-analysis of randomized controlled trials showed that ACL reconstruction with technique of remnant preservation cannot provide superior clinical outcomes compared with the standard procedure.

  1. Effect of brushing on fluoride release from 3 bracket adhesives.

    Science.gov (United States)

    Staley, Robert N; Mack, Steven J; Wefel, James S; Vargas, Marcos A; Jakobsen, Jane R

    2004-09-01

    The purpose of this in vitro study was to compare fluoride ion release from 3 orthodontic bracket adhesives with and without brushing the bracketed teeth with a fluoridated dentifrice. The bracket adhesives included a light-cured composite resin (Transbond; 3M Unitek, Monrovia, Calif), a fluoride-releasing composite resin (Advance; L D Caulk Division, Dentsply International, Milford, Del), and a resin-modified glass ionomer (Fuji Ortho LC; GC America, Alsip, Ill). The teeth in the control group were not bonded with brackets. Sixty extracted human teeth were randomly assigned to 6 groups of 10 each: (1) Transbond, brushed; (2) Advance, brushed; (3) Advance, not brushed; (4) Fuji, brushed; (5) Fuji, not brushed; and (6) control, brushed. After bonding, each tooth was placed in a sealed plastic test tube containing 4 ml of deionized water. The toothpaste used in brushing contained 0.15% weight per volume sodium fluoride, 1500 parts per million parts fluoride (Winter-fresh gel; Colgate-Palmolive Co., New York, NY). Brushing began 24 hours after the teeth were bonded and placed in deionized water. After brushing, the teeth were thoroughly rinsed with deionized water and returned to a sealed test tube. Fluoride measurements were taken before brushing began, at intervals of 72 hours for 22 days, and 90 and 93 days after bonding. Findings included: (1) brushing significantly increased the release of fluoride ions from the teeth in the composite resin and control groups, (2) the enamel crowns of the unbonded control teeth absorbed and re-released a substantial amount of fluoride ions obtained from the toothpaste, (3) the brushed group of teeth bonded with the fluoride-releasing composite resin released significantly more fluoride on the last 4 days that measurements were taken after brushing than the nonbrushed group bonded with the same adhesive, (4) the brushed group of teeth bonded with the resin-modified glass ionomer released significantly more fluoride on the last 4

  2. Maslov indices, Poisson brackets, and singular differential forms

    Science.gov (United States)

    Esterlis, I.; Haggard, H. M.; Hedeman, A.; Littlejohn, R. G.

    2014-06-01

    Maslov indices are integers that appear in semiclassical wave functions and quantization conditions. They are often notoriously difficult to compute. We present methods of computing the Maslov index that rely only on typically elementary Poisson brackets and simple linear algebra. We also present a singular differential form, whose integral along a curve gives the Maslov index of that curve. The form is closed but not exact, and transforms by an exact differential under canonical transformations. We illustrate the method with the 6j-symbol, which is important in angular-momentum theory and in quantum gravity.

  3. Intrapulpal Temperature Increases Caused by 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets During Simulated Pulpal Fluid Circulation.

    Science.gov (United States)

    Stein, Steffen; Wenzler, Johannes; Hellak, Andreas; Schauseil, Michael; Korbmacher-Steiner, Heike; Braun, Andreas

    2018-01-03

    This study investigated temperature increases in dental pulp resulting from laser-assisted debonding of ceramic brackets using a 445-nm diode laser. Eighteen ceramic brackets were bonded in standardized manner to 18 caries-free human third molars. Pulpal fluid circulation was simulated by pumping distilled water at 37°C through the pulp chamber. The brackets were irradiated with a 445-nm diode laser. Temperatures were measured using a thermal camera at points P1 (center of the pulp) and P2 (in the hard dental tissue) at the baseline (T0), at the start and end of laser application (T1 and T2), and the maximum during the sequence (T max ). Significant differences in the temperatures measured at P1 and P2 were observed among T0, T1, T2, and T max . Significant increases in temperature were noted at points P1 and P2, between T1 and T2, T1 and T max , and T2 and T max . The maximum P2 values were significantly higher than at P1. The maximum temperature increase measured in the pulp was 2.23°C, lower than the critical threshold of 5.5°C. On the basis of the laser settings used, there is no risk to the vitality of dental pulp during laser-assisted debonding of ceramic brackets with a 445-nm diode laser.

  4. Development of sulfide calibration standards for the laser ablation inductively-coupled plasma mass spectrometry technique

    Science.gov (United States)

    Wilson, S.A.; Ridley, W.I.; Koenig, A.E.

    2002-01-01

    The requirements of standard materials for LA-ICP-MS analysis have been difficult to meet for the determination of trace elements in sulfides. We describe a method for the production of synthetic sulfides by precipitation from solution. The method is detailed by the production of approximately 200 g of a material, PS-1, with a suite of chalcophilic trace elements in an Fe-Zn-Cu-S matrix. Preliminary composition data, together with an evaluation of the homogeneity for individual elements, suggests that this type of material meets the requirements for a sulfide calibration standard that allows for quantitative analysis. Contamination of the standard with Na suggests that H2S gas may prove a better sulfur source for future experiments. We recommend that calibration data be collected in whatever mode is closest to that employed for the analysis of the unknown material, because of variable fractionation effects as a function of analytical mode. For instance, if individual spot analyses are attempted on unknown sample, then a raster of several individual spot analyses, not a continuous scan, should be collected and averaged for the standard. Hg and Au are exceptions to the above and calibration data should always be collected in a scanning mode. Au is more heterogeneously distributed than other trace metals and large-area scans are required to provide an average value for calibration purposes. We emphasize that the values given in Table 1 are preliminary values. Further chemical characterization of this standard, through a round-robin analysis program, will allow the USGS to provide both certified and recommended values for individual elements. The USGS has developed PS-1 as a potential new LA-ICP-MS standard for use by the analytical community, and requests for this material should be addressed to S. Wilson. However, it is stressed that an important aspect of the method described here is the flexibility for individual investigators to produce sulfides with a wide range

  5. Standard practice for examination of welds using the alternating current field measurement technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice describes procedures to be followed during alternating current field measurement examination of welds for baseline and service-induced surface breaking discontinuities. 1.2 This practice is intended for use on welds in any metallic material. 1.3 This practice does not establish weld acceptance criteria. 1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system might not be exact equivalents; therefore, each system shall be used independently of the other. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  6. Relationship between alveolar bone measured by 125I absorptiometry with analysis of standardized radiographs: 2. Bjorn technique

    International Nuclear Information System (INIS)

    Ortman, L.F.; McHenry, K.; Hausmann, E.

    1982-01-01

    The Bjorn technique is widely used in periodontal studies as a standardized measure of alveolar bone. Recent studies have demonstrated the feasibility of using 125 I absorptiometry to measure bone mass. The purpose of this study was to compare 125 I absorptiometry with the Bjorn technique in detecting small sequential losses of alveolary bone. Four periodontal-like defects of incrementally increasing size were produced in alveolar bone in the posterior segment of the maxilla of a human skull. An attempt was made to sequentially reduce the amount of bone in 10% increments until no bone remained, a through and through defect. The bone remaining at each step was measured using 125 I absorptiometry. At each site the 125 I absorptiometry measurements were made at the same location by fixing the photon source to a prefabricated precision-made occlusal splint. This site was just beneath the crest and midway between the borders of two adjacent teeth. Bone loss was also determined by the Bjorn technique. Standardized intraoral films were taken using a custom-fitted acrylic clutch, and bone measurements were made from the root apex to coronal height of the lamina dura. A comparison of the data indicates that: (1) in early bone loss, less than 30%, the Bjorn technique underestimates the amount of loss, and (2) in advanced bone loss, more than 60% the Bjorn technique overestimates it

  7. Applying Standard Independent Verification and Validation (IVV) Techniques Within an Agile Framework: Is There a Compatibility Issue?

    Science.gov (United States)

    Dabney, James B.; Arthur, James Douglas

    2017-01-01

    Agile methods have gained wide acceptance over the past several years, to the point that they are now a standard management and execution approach for small-scale software development projects. While conventional Agile methods are not generally applicable to large multi-year and mission-critical systems, Agile hybrids are now being developed (such as SAFe) to exploit the productivity improvements of Agile while retaining the necessary process rigor and coordination needs of these projects. From the perspective of Independent Verification and Validation (IVV), however, the adoption of these hybrid Agile frameworks is becoming somewhat problematic. Hence, we find it prudent to question the compatibility of conventional IVV techniques with (hybrid) Agile practices.This paper documents our investigation of (a) relevant literature, (b) the modification and adoption of Agile frameworks to accommodate the development of large scale, mission critical systems, and (c) the compatibility of standard IVV techniques within hybrid Agile development frameworks. Specific to the latter, we found that the IVV methods employed within a hybrid Agile process can be divided into three groups: (1) early lifecycle IVV techniques that are fully compatible with the hybrid lifecycles, (2) IVV techniques that focus on tracing requirements, test objectives, etc. are somewhat incompatible, but can be tailored with a modest effort, and (3) IVV techniques involving an assessment requiring artifact completeness that are simply not compatible with hybrid Agile processes, e.g., those that assume complete requirement specification early in the development lifecycle.

  8. MIMO wireless networks channels, techniques and standards for multi-antenna, multi-user and multi-cell systems

    CERN Document Server

    Clerckx, Bruno

    2013-01-01

    This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal. Reflecting developments

  9. Free-field reciprocity calibration of laboratory standard (LS) microphones using a time selective technique

    DEFF Research Database (Denmark)

    Rasmussen, Knud; Barrera Figueroa, Salvador

    2006-01-01

    Although the basic principle of reciprocity calibration of microphones in a free field is simple, the practical problems are complicated due to the low signal-to-noise ratio and the influence of cross talk and reflections from the surroundings. The influence of uncorrelated noise can be reduced...... by conventional narrow-band filtering and time averaging, while correlated signals like cross talk and reflections can be eliminated by using time-selective postprocessing techniques. The technique used at DPLA overcomes both these problems using a B&K Pulse analyzer in the SSR mode (steady state response......) and an FFT-based time-selective technique. The complex electrical transfer impedance is measured in linear frequency steps from a few kHz to about three times the resonance frequency of the microphones. The missing values at low frequencies are estimated from a detailed knowledge of the pressure...

  10. Effectiveness and efficiency of a CAD/CAM orthodontic bracket system.

    Science.gov (United States)

    Brown, Matthew W; Koroluk, Lorne; Ko, Ching-Chang; Zhang, Kai; Chen, Mengqi; Nguyen, Tung

    2015-12-01

    The first straight-wire appliance was introduced over 40 years ago to increase the consistency and efficiency of orthodontic treatment. More recently, computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been used to create individualized orthodontic appliances. The purpose of this study was to investigate the clinical effectiveness and efficiency of CAD/CAM customized orthodontic appliances compared with direct and indirect bonded stock orthodontic brackets. This retrospective study included 3 treatment groups: group 1 patients were direct bonded with self-ligating appliances, group 2 patients were indirect bonded with self-ligating appliances, and group 3 patients were indirect bonded with CAD/CAM self-ligating appliances. Complete pretreatment and posttreatment records were obtained for all patients. The American Board of Orthodontics (ABO) Discrepancy Index was used to evaluate the pretreatment records, and the posttreatment outcomes were analyzed using the ABO Cast-Radiograph Evaluation. All data collection and analysis were completed by 1 evaluator. There were no statistically significant differences in the ABO Discrepancy Index or the ABO Cast-Radiograph Evaluation among the groups. Treatment times for the 3 groups were significantly different; the CAD/CAM group was the shortest at 13.8 ± 3.4 months, compared with 21.9 ± 5.0 and 16.9 ± 4.1 months for the direct bonded and indirect bonded groups, respectively. The number of treatment appointments for the CAD/CAM group was significantly fewer than for the direct bonded group. The CAD/CAM orthodontic bracket system evaluated in this study was as effective in treatment outcome measures as were standard brackets bonded both directly and indirectly. The CAD/CAM appliance was more efficient in regard to treatment duration, although the decrease in total archwire appointments was minimal. Further investigation is needed to better quantify the clinical benefits of CAD/CAM orthodontic

  11. Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva.

    Science.gov (United States)

    Tahmasbi, Soodeh; Sheikh, Tahereh; Hemmati, Yasamin B

    2017-03-01

    To investigate the galvanic corrosion of brackets manufactured by four different companies coupled with stainless steel (SS) or nickel-titanium (NiTi) wires in an artificial saliva solution. A total of 24 mandibular central incisor Roth brackets of four different manufacturers (American Orthodontics, Dentaurum, Shinye, ORJ) were used in this experimental study. These brackets were immersed in artificial saliva along with SS or NiTi orthodontic wires (0.016'', round) for 28 days. The electric potential difference of each bracket/ wire coupled with a saturated calomel reference electrode was measured via a voltmeter and recorded constantly. Corrosion rate (CR) was calculated, and release of ions was measured with an atomic absorption spectrometer. Stereomicroscope was used to evaluate all samples. Then, samples with corrosion were further assessed by scanning electron microscope and energy-dispersive X-ray spectroscopy. Two-way analysis of variance was used to analyze data. Among ions evaluated, release of nickel ions from Shinye brackets was significantly higher than that of other brackets. The mean potential difference was significantly lower in specimens containing a couple of Shinye brackets and SS wire compared with other specimens. No significant difference was observed in the mean CR of various groups (p > 0.05). Microscopic evaluation showed corrosion in two samples only: Shinye bracket coupled with SS wire and American Orthodontics bracket coupled with NiTi wire. Shinye brackets coupled with SS wire showed more susceptibility to galvanic corrosion. There were no significant differences among specimens in terms of the CR or released ions except the release of Ni ions, which was higher in Shinye brackets.

  12. The Effect of Long-Term Therapeutics, Prophylaxis and Screening Techniques on Aircrew Medical Standards.

    Science.gov (United States)

    1981-03-01

    350. voel RA, Kirch DC, LeFree MT, Rainwater JO, Jensen DP, Steele PP. Thallium-201 myocardial perfusion scintiaraphy: results of standard aad multi...Reference 3. Further Reference 4.Security Clasification of Document A;ARD4"P-3 10 ISBN 92-835-0288-4 UNCLASSIFIE) 5 Originator Advi,,ory Group for

  13. Admissions Standards and the Use of Key Marketing Techniques by United States' Colleges and Universities.

    Science.gov (United States)

    Goldgehn, Leslie A.

    1989-01-01

    A survey of admissions deans and directors investigated the use and perceived effectiveness of 15 well-known marketing techniques: advertising, advertising research, a marketing plan, market positioning, market segmentation, marketing audit, marketing research, pricing, program and service accessibility, program development, publicity, target…

  14. International intercomparison of standards for low collision kerma rates in air by means of low dose TLD techniques

    International Nuclear Information System (INIS)

    Spanne, P.; Carlsson, C.A.; Carlsson, G.A.

    1984-01-01

    An international intercomparison of standards for calibration of radiation protection instruments is described. The intercomparison involved collision kerma rates in air in the range 5.7 to 7.400 μGy.h -1 and was performed using low dose TLD techniques with TL-LiF dosemeters. The dosemeters were specifically tested with regard to their dose rate dependence, but none was found. (author)

  15. Assessing the service quality of Iran military hospitals: Joint Commission International standards and Analytic Hierarchy Process (AHP) technique.

    Science.gov (United States)

    Bahadori, Mohammadkarim; Ravangard, Ramin; Yaghoubi, Maryam; Alimohammadzadeh, Khalil

    2014-01-01

    Military hospitals are responsible for preserving, restoring and improving the health of not only armed forces, but also other people. According to the military organizations strategy, which is being a leader and pioneer in all areas, providing quality health services is one of the main goals of the military health care organizations. This study was aimed to evaluate the service quality of selected military hospitals in Iran based on the Joint Commission International (JCI) standards and comparing these hospitals with each other and ranking them using the analytic hierarchy process (AHP) technique in 2013. This was a cross-sectional and descriptive study conducted on five military hospitals, selected using the purposive sampling method, in 2013. Required data collected using checklists of accreditation standards and nominal group technique. AHP technique was used for prioritizing. Furthermore, Expert Choice 11.0 was used to analyze the collected data. Among JCI standards, the standards of access to care and continuity of care (weight = 0.122), quality improvement and patient safety (weight = 0.121) and leadership and management (weight = 0.117) had the greatest importance, respectively. Furthermore, in the overall ranking, BGT (weight = 0.369), IHM (0.238), SAU (0.202), IHK (weight = 0.125) and SAB (weight = 0.066) ranked first to fifth, respectively. AHP is an appropriate technique for measuring the overall performance of hospitals and their quality of services. It is a holistic approach that takes all hospital processes into consideration. The results of the present study can be used to improve hospitals performance through identifying areas, which are in need of focus for quality improvement and selecting strategies to improve service quality.

  16. Evaluation of a standard breast tangent technique: a dose-volume analysis of tangential irradiation using three-dimensional tools

    International Nuclear Information System (INIS)

    Krasin, Matthew; McCall, Anne; King, Stephanie; Olson, Mary; Emami, Bahman

    2000-01-01

    Purpose: A thorough dose-volume analysis of a standard tangential radiation technique has not been published. We evaluated the adequacy of a tangential radiation technique in delivering dose to the breast and regional lymphatics, as well as dose delivered to underlying critical structures. Methods and Materials: Treatment plans of 25 consecutive women with breast cancer undergoing lumpectomy and adjuvant breast radiotherapy were studied. Patients underwent two-dimensional (2D) treatment planning followed by treatment with standard breast tangents. These 2D plans were reconstructed without modification on our three-dimensional treatment planning system and analyzed with regard to dose-volume parameters. Results: Adequate coverage of the breast (defined as 95% of the target receiving at least 95% of the prescribed dose) was achieved in 16 of 25 patients, with all patients having at least 85% of the breast volume treated to 95% of the prescribed dose. Only 1 patient (4%) had adequate coverage of the Level I axilla, and no patient had adequate coverage of the Level II axilla, Level III axilla, or the internal mammary lymph nodes. Conclusion: Three-dimensional treatment planning is superior in quantification of the dose received by the breast, regional lymphatics, and critical structures. The standard breast tangent technique delivers an adequate dose to the breast but does not therapeutically treat the regional lymph nodes in the majority of patients. If coverage of the axilla or internal mammary lymph nodes is desired, alternate beam arrangements or treatment fields will be necessary

  17. Phytochemical analysis and standardization of Strychnos nux-vomica extract through HPTLC techniques

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar Patel

    2012-05-01

    Full Text Available Objective: The objective is to develop a noval qualitative and quantitative method by which we can determine different phytoconstituents of Strychnos nux-vomica L. Methods: To profile the phyconstituents of Strychnos nux-vomica, in the present study hydroalcoholic extract of Strychnos nux-vomica was subjected to preliminary phytochemical analysis, antimicrobial activities against certain pathogenic microorganisms, solubility test, loss on drying and pH value. Extract was also subjected to the quantitative analysis including total phenol, flavonoid and heavy metal analysis. Quantitative analysis was performed through HPTLC methods using strychnine and brucine as a standard marker. Results: Phytochemical analysis revealed the presence of alkaloid, carbohydrate, tannin, steroid, triterpenoid and glycoside in the extract. Total flavonoid and phenol content of Strychnos nux-vomica L extract was found to be 0.40 % and 0.43%. Result showed that the level of heavy metal (lead, arsenic, mercury and cadmium complie the standard level. Total bacterial count, yeast and moulds contents were found to be under the limit whereas E. coli and salmonella was found to be absent in the extract. Content of strychnine and brucine were found to be 4.75% and 3.91%. Conclusions: These studies provide valluable information for correct identification and selection of the drug from various adulterations. In future this study will be helpful for the quantitative analysis as well as standardization of the Strychnos nux-vomica L.

  18. A Simple low-cost device enables four epi-illumination techniques on standard light microscopes.

    Science.gov (United States)

    Ishmukhametov, Robert R; Russell, Aidan N; Wheeler, Richard J; Nord, Ashley L; Berry, Richard M

    2016-02-08

    Back-scattering darkfield (BSDF), epi-fluorescence (EF), interference reflection contrast (IRC), and darkfield surface reflection (DFSR) are advanced but expensive light microscopy techniques with limited availability. Here we show a simple optical design that combines these four techniques in a simple low-cost miniature epi-illuminator, which inserts into the differential interference-contrast (DIC) slider bay of a commercial microscope, without further additions required. We demonstrate with this device: 1) BSDF-based detection of Malarial parasites inside unstained human erythrocytes; 2) EF imaging with and without dichroic components, including detection of DAPI-stained Leishmania parasite without using excitation or emission filters; 3) RIC of black lipid membranes and other thin films, and 4) DFSR of patterned opaque and transparent surfaces. We believe that our design can expand the functionality of commercial bright field microscopes, provide easy field detection of parasites and be of interest to many users of light microscopy.

  19. Cytotoxic effects of polycarbonate-based orthodontic brackets by activation of mitochondrial apoptotic mechanisms

    NARCIS (Netherlands)

    Kloukos, D.; Taoufik, E.; Eliades, T.; Katsaros, C.; Eliades, G.

    2013-01-01

    OBJECTIVES: The aim of the study was to evaluate the biological effects of water eluents from polycarbonate based esthetic orthodontic brackets. METHODS: The composite polycarbonate brackets tested were Silkon Plus (SL, fiber-glass-reinforced), Elan ME (EL, ceramic particle-reinforced) and Elegance

  20. Friction Forces during Sliding of Various Brackets for Malaligned Teeth: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Vito Crincoli

    2013-01-01

    Full Text Available Aims. To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3 and low-friction (Synergy brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine. Methods. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA was carried out to investigate whether the following factors affect the values of friction force: (i degree of malalignment, (ii diameter of the orthodontic wire, and (iii bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed. Results. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments. Conclusion. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance.

  1. Forces produced by different nonconventional bracket or ligature systems during alignment of apically displaced teeth.

    Science.gov (United States)

    Baccetti, Tiziano; Franchi, Lorenzo; Camporesi, Matteo; Defraia, Efisio; Barbato, Ersilia

    2009-05-01

    To analyze the forces released by four types of passive stainless steel self-ligating brackets (SLBs), and by two nonconventional elastomeric ligature-bracket systems when compared with conventional elastomeric ligatures on conventional stainless steel brackets during the alignment of apically displaced teeth at the maxillary arch. An experimental model consisting of five brackets was used to assess the forces released by the seven different ligature-bracket systems with 0.012'' or 0.014'' superelastic nickel titanium wire in the presence of different amounts of apical displacement of the canine (ranging from 1.5 mm to 6 mm). Comparisons between the different types of bracket/wire/ ligature systems were carried out by means of ANOVA on ranks with Dunnett's post hoc test (P < .05). When correction of a misalignment greater than 3 mm is attempted, a noticeable amount of force for alignment is generated by passive SLBs and nonconventional elastomeric ligature-bracket systems, and a null amount of force is released in the presence of conventional elastomeric ligatures on conventional brackets. When minimal apical displacement is needed (1.5 mm), the differences in performance between low-friction and conventional systems are minimal. These differences become significant when correction of a misalignment of greater than 3.0 mm is attempted.

  2. Changes in the surface roughness and friction coefficient of orthodontic bracket slots before and after treatment.

    Science.gov (United States)

    Liu, Xiaomo; Lin, Jiuxiang; Ding, Peng

    2013-01-01

    In this study, we tested the surface roughness of bracket slots and the friction coefficient between the bracket and the stainless steel archwire before and after orthodontic treatment. There were four experimental groups: groups 1 and 2 were 3M new and retrieved brackets, respectively, and groups 3 and 4 were BioQuick new and retrieved brackets, respectively. All retrieved brackets were taken from patients with the first premolar extraction and using sliding mechanics to close the extraction space. The surface roughness of specimens was evaluated using an optical interferometry profilometer, which is faster and nondestructive compared with a stylus profilometer, and provided a larger field, needing no sample preparation, compared with atomic force microscopy. Orthodontic treatment resulted in significant increases in surface roughness and coefficient of friction for both brands of brackets. However, there was no significant difference by brand for new or retrieved brackets. These retrieval analysis results highlight the necessity of reevaluating the properties and clinical behavior of brackets during treatment to make appropriate treatment decisions. © Wiley Periodicals, Inc.

  3. Loss of surface enamel after bracket debonding : An in-vivo and ex-vivo evaluation

    NARCIS (Netherlands)

    Pont, Huib Berghauser; Özcan, Mutlu; Bagis, Bora; Ren, Yijin

    2010-01-01

    INTRODUCTION: The objective of this study was to evaluate the surface enamel after bracket debonding and residual resin removal. METHODS: Thirty patients (female, 20; male, 10; mean age, 18.4 years) who completed orthodontic treatment with fixed appliances (Twin Brackets, 3M Unitek, Monrovia, Calif)

  4. Shear bond strength of precoated orthodontic brackets: an in vivo study

    Directory of Open Access Journals (Sweden)

    Ali H Hassan

    2010-06-01

    Full Text Available Ali H HassanDepartment of Preventive Dental Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi ArabiaObjective: To evaluate the shear bond strength of precoated orthodontic brackets bonded with self-etching primer relative to that of noncoated conventionally-bonded brackets at two different time intervals.Methods: Twenty-one subjects were selected for randomized split-mouth bonding of two types of brackets to the maxillary arch. Half of the teeth had precoated brackets bonded using selfetching adhesive, and the other half had regular brackets bonded using Transbond XT adhesive. Nitinol wires were tied to the upper arch and were left until the time of debonding. The patients were randomly divided into two groups: one debonded after one hour and the other debonded two weeks after the initial wire placement. The shear bond strength was directly recorded from the patients’ mouths using an in vivo debonding device.Results: There were no significant differences in shear bond strength between the precoated and conventional groups or within each group at different time intervals. There were significant differences between anterior and posterior teeth in both the precoated and conventional groups. Conclusion: Pre-coated brackets bonded with self-etching adhesive have the same bonding strength as the conventionally bonded brackets.Keywords: shear bond, bonding, orthodontics, precoated, brackets, self-etching adhesive

  5. Comparison of static friction with self-ligating, modified slot design and conventional brackets

    Directory of Open Access Journals (Sweden)

    Raquel Morais Castro

    2013-07-01

    Full Text Available OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA, with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA and conventional (Kirium, Abzil, São José do Rio Preto, Brazil. The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA. The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (p<0.05 in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05. The angulation influenced friction (p<0.05 when the brackets were associated with a 0.018" wire. CONCLUSION: Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

  6. Caries outcomes after orthodontic treatment with fixed appliances: do lingual brackets make a difference?

    NARCIS (Netherlands)

    van der Veen, M.H.; Attin, R.; Schwestka-Polly, R.; Wiechmann, D.

    2010-01-01

    Orthodontic treatment with fixed appliances is considered a risk factor for the development of white spot caries lesions (WSL). Traditionally, brackets are bonded to the buccal surfaces. Lingual brackets are developing rapidly and have become more readily available. Buccal surfaces are considered to

  7. Magnetic resonance imaging artifacts caused by brackets of various materials - An in vivo study

    Directory of Open Access Journals (Sweden)

    Deepti Razdan

    2012-01-01

    Patients who might require repeated MRI scans, can be treated orthodontically with ceramic/composite/anterior ceramic and posterior stainless steel brackets. When the region of interest is above the orbit or beyond the posterior wall of the pharynx, no demonstrable artifacts were recorded with various types of brackets included in the present study.

  8. Shear Bond Strength of DentStat(trademark) for Bracket Bonding to Gold, Ceramic, and Enamel

    Science.gov (United States)

    2012-12-21

    when bonding ceramic brackets to enamel, one good use for this material would be for bonding brackets in patients with bad hygiene that demanded...releasing materials. Biomaterials . 2003 Jun; 2004(14): 2451-61. Yap AU, Chung SM, Chow WS, Tsai KT, Lim CT. Fracture resistance of compomer and

  9. Static and kinetic frictional forces of silica-insert ceramic brackets with coated archwires in artificial saliva

    Directory of Open Access Journals (Sweden)

    Mostafa Shahabi

    2017-01-01

    Conclusion: From the standpoint of friction, SIC brackets may serve well, even better than SS brackets, in sliding mechanics. The coating layer of the archwires may delaminate and lost, causing an impediment to tooth movement.

  10. From conventional to self-ligating bracket systems: Is it possible to aggregate the experience with the former to the use of the latter?

    Directory of Open Access Journals (Sweden)

    Anderson Capistrano

    2014-06-01

    Full Text Available INTRODUCTION: Orthodontics, just as any other science, has undergone advances in technology that aim at improving treatment efficacy with a view to reducing treatment time, providing patients with comfort, and achieving the expected, yet hardly attained long-term stability. The current advances in orthodontic technology seem to represent a period of transition between conventional brackets (with elastic ligatures and self-ligating brackets systems. Scientific evidence does not always confirm the clear clinical advantages of the self-ligating system, particularly with regard to reduced time required for alignment and leveling (a relatively simple protocol, greater comfort for patients, and higher chances of performing treatment without extractions - even though the number of extractions is more closely related to patient's facial morphological pattern, regardless of the technique of choice. Orthodontics has recently and brilliantly used bracket individualization in compensatory treatment with a view to improving treatment efficacy with lower biological costs and reduced treatment time. OBJECTIVE: This paper aims at presenting a well-defined protocol employed to produce a better treatment performance during this period of technological transition. It explores the advantages of each system, particularly with regards to reduced treatment time and increased compensatory tooth movement in adult patients. It particularly addresses compensable Class III malocclusions, comparing the system of self-ligating brackets, with which greater expansive and protrusive tooth movement (maxillary arch is expected, with conventional brackets Capelozza Prescription III, with which maintaining the original form of the arch (mandibular arch with as little changes as possible is key to yield the desired results.

  11. Standardization of the radioimmunoassay technique for the determination of human gastrin and its clinical application

    International Nuclear Information System (INIS)

    Peig Ginabredra, M.G.

    1989-01-01

    It was developed and standardized a system of radioimmunoassay for the determination of gastrin, employing synthetic human gastrin for radioiodination and preparation of standard as well as specific antibody raised rabbits. The hormone was labeled with 125 I by the Cloramine T techique and purified by anion exchange chromatography in QAE-Sephadex A-25, being determined its specific activity. The tracer thus obtained was submitted to analysis of purity by poliacrilamide gel eletrophoresis and precipitation of proteins by trichloroacetic acid. Its stability evaluated according to the time of storage, being its purity and adequation for the use in radioimmunoassay also compared to a tracer obtained from a commercial diagnosis kit. The assays were performed by incubation of radioiodinated gastrin, standard gastrin prepared in plasma free from this hormone (from zero to 500 pmol/l) or samples to be assayed with the antiserum for 4 days at 4 0 C. The separation between the free gastrin and the gastrin bound to the antibody was carried out by adsorption of the free hormone to the charcoal, whose ideal concentration was previously determined. Plasma free from gastrin was obtained from time-expired blood bank plasma submitted to extraction with charcoal. When performed the quality control, this radioimmunoassay was shown specific, accurate, precise and sensitive, allowing the performance of valid assays. Its validation was even confirmed by clear discrimination not only of the gastrin concentration in subjects with very low levels (gastrectomized) and extremely high levels (Zollinger-Ellison syndrome) as well as gastrin concentrations in subjects with other diseases, such as Chagas disease, pernicious anemia and chronic renal failure. (author) [pt

  12. Characterization of the neutron sources storage pool of the Neutron Standards Laboratory, using Montecarlo Techniques

    International Nuclear Information System (INIS)

    Campo Blanco, X.

    2015-01-01

    The development of irradiation damage resistant materials is one of the most important open fields in the design of experimental facilities and conceptual nucleoelectric fusion plants. The Neutron Standards Laboratory aims to contribute to this development by allowing the neutron irradiation of materials in its calibration neutron sources storage pool. For this purposes, it is essential to characterize the pool itself in terms of neutron fluence and spectra due to the calibration neutron sources. In this work, the main features of this facility are presented and the characterization of the storage pool is carried out. Finally, an application is shown of the obtained results to the neutron irradiation of material.

  13. Effects of silane application on the shear bond strength of ceramic orthodontic brackets to enamel surface

    Directory of Open Access Journals (Sweden)

    Pinandi Sri Pudyani

    2016-12-01

    Full Text Available Background: Fixed orthodontic appliances with ceramic brackets are used frequently to fulfill the aesthetic demand of patient through orthodontic treatment. Ceramic brackets have some weaknesses such as bond strength and enamel surface damage. In high bond strength the risk of damage in enamel surfaces increases after debonding. Purpose: This study aimed to determine the effect of silane on base of bracket and adhesive to shear bond strength and enamel structure of ceramic bracket. Method: Sixteen extracted upper premolars were randomly divided into four groups based on silane or no silane on the bracket base and on the adhesive surface. Design of the base on ceramic bracket in this research was microcrystalline to manage the influence of mechanical interlocking. Samples were tested in shear mode on a universal testing machine after attachment. Following it, adhesive remnant index (ARI scores were used to assess bond failure site. Statistical analysis was performed using a two-way Anova and the Mann-Whitney test. A scanning electron microscope (SEM with a magnification of 2000x was used to observe enamel structure after debonding. Result: Shear bond strength was increased between group without silane and group with silane on the base of bracket (p<0,05. There was no significance different between group without silane and group with silane on adhesive (p<0,05. Conclusion: Application of silane on base of bracket increases shear bond strength, however, application of silane on adhesive site does not increase shear bond strength of ceramic bracket. Most bonding failure occurred at the enamel adhesive interface and damage occurred on enamel structure in group contains silane of ceramic bracket.

  14. Physical and chemical properties of orthodontic brackets after 12 and 24 months: in situ study

    Directory of Open Access Journals (Sweden)

    Bernardo de Azevedo Bahia MENDES

    2014-06-01

    Full Text Available Objective: The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. Material and Methods: Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide® elastomeric ligature. Results: The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface. Conclusion: The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction.

  15. Systematic solutions to solve the Dirac bracket commutators

    International Nuclear Information System (INIS)

    Ananias Neto, Jorge

    2009-01-01

    Full text. The quantization of a dynamical system with second class constraints is usually performed by using the method proposed by Dirac, Bergman and coworkers. The constraints are classified as primary and secondary ones. Secondary constraints are obtained from the condition that primary constraints are conserved in time. We must repeat the condition requiring time derivative of secondary constraints vanish until all independent constraints are obtained. If the whole second class constraints are established, the so called Dirac bracket can be defined. In the case of the total second class constraints are two, the Dirac Bracket for the canonical variables A and B is given by {A,B} DB = {A,B} + 1/{T 1 , T 2 } {A, T 1 { {T 2 , B} - {A, T 2 } {T 1 , B } where T1 and T2 are the second class constraints. The quantum mechanics commutators are given by the replacement { } DB → i h/2π. From the particular expressions of the Dirac bracket (DB) commutators, we can derive the physical operators of a specific theory. These operators together with the physical states dictate the rules that govern the quantum system with constraints. However, due to the fact that the commutators are coordinates dependent and there are ordering problems, the obtainment of the physical operators is a difficult task. In this work we develop a systematic procedure that derives physical operators in coordinates space that satisfy the DB commutators. For this purpose, we use the Gauge Unfixing formalism (GU), a method that converts second class systems into first class ones without to extend the original phase space variables. We will see that, after converting the second class variables into first class ones and substituting these gauge invariant variables by operators, we obtain solutions of the DB commutators. Thus, we can employ the idea of the GU formalism in order to establish a systematic procedure that solves the DB commutators. We apply our formalism in the free particle constrained to

  16. Effect of Surface Treatment on Enamel Cracks after Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching versus Acid-Etching

    OpenAIRE

    Hassanali Ghaffari; Amirhossein Mirhashemi; Tahereh Baherimoghadam; Amir Azmi; Reza Rasooli

    2017-01-01

    Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and the conventional acid-etching technique.Materials and Methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the ...

  17. Evaluation of Visualization Using a 50/50 (Contrast Media/Glucose 5% Solution) Technique for Radioembolization as an Alternative to a Standard Sandwich Technique.

    Science.gov (United States)

    Paprottka, Karolin J; Todica, Andrei; Ilhan, Harun; Rübenthaler, Johannes; Schoeppe, Franziska; Michl, Marlies; Heinemann, Volker; Bartenstein, Peter; Reiser, Maximilian F; Paprottka, Philipp M

    2017-11-01

    Radioembolization (RE) with 90 yttrium ( 90 Y) resin microspheres generally employs a sandwich technique with separate sequential administration of contrast medium (CM), followed by vehicle (e.g., glucose 5% [G5] solution), then 90 Y resin microspheres (in G5), then G5, and then CM again to avoid contact of CM and microspheres under fluoroscopic guidance. This study evaluates the visualization quality and safety of a modified sandwich technique with a 50/50-mixture of CM (Imeron 300) and G5 for administration of 90 Y resin microspheres. A retrospective analysis of 81 RE procedures in patients with primary or secondary liver tumors was performed. The quality of angiographic visualization of the hepatic vessels was assessed before the first injection and immediately before the whole dose has been injected. Visualization and flow rate were graded on a 5-point scale: 1 = very good to 5 = not visible/no antegrade flow. Univariate logistic regression models and multiple linear regression models were used to evaluate the prognostic variables associated with visualization and flow scores. Visualization quality was inversely related to flow rate, the lower the flow rate the better the grade of the visualization. Visualization quality was also inversely related to body-mass-index (BMI). Performing RE with the 50/50-CM/G5 mixture resulted in a mean injection time for 1 GBq of 15 min. No clinically significant adverse events, including radiation-induced liver disease were reported. RE with a 50/50-mixture of CM and G5 for administration of 90 Y resin microspheres in a modified sandwich technique is a safe administration alternative and provides good visualization of hepatic vessels, which is inversely dependent on flow rate and BMI. Injection time was reduced compared with our experience with the standard sandwich technique.

  18. Robot-assisted repair of tricuspid leaflet prolapse using standard valvuloplasty techniques.

    Science.gov (United States)

    Seder, Christopher W; Suri, Rakesh M; Rehfeldt, Kent; Pislaru, Sorin; Burkhart, Harold M

    2012-11-01

    While minimally invasive approaches are used routinely to correct severe mitral regurgitation due to leaflet prolapse, isolated tricuspid valve prolapse is less frequent and usually addressed via sternotomy. A 34-year-old female presented with exertional dyspnea and severe tricuspid regurgitation due to an unsupported anterior leaflet causing prolapse, a tethered septal leaflet, and dilated annulus. Herein, the technique is described of a robot-assisted tricuspid valve repair using established open valvuloplasty principles. The robotic repair was performed by the placement of Gore-Tex neochordae from the anterior papillary muscle to the anterior tricuspid leaflet, plication of the anteroseptal and anteroposterior commissures, closure of an anterior leaflet cleft, and the insertion of an annuloplasty band. The patient had an uncomplicated hospital course and was dismissed home on the third postoperative day.

  19. Model-Based Data Integration and Process Standardization Techniques for Fault Management: A Feasibility Study

    Science.gov (United States)

    Haste, Deepak; Ghoshal, Sudipto; Johnson, Stephen B.; Moore, Craig

    2018-01-01

    This paper describes the theory and considerations in the application of model-based techniques to assimilate information from disjoint knowledge sources for performing NASA's Fault Management (FM)-related activities using the TEAMS® toolset. FM consists of the operational mitigation of existing and impending spacecraft failures. NASA's FM directives have both design-phase and operational-phase goals. This paper highlights recent studies by QSI and DST of the capabilities required in the TEAMS® toolset for conducting FM activities with the aim of reducing operating costs, increasing autonomy, and conforming to time schedules. These studies use and extend the analytic capabilities of QSI's TEAMS® toolset to conduct a range of FM activities within a centralized platform.

  20. Standard practice for evaluation of hydrogen uptake, permeation, and transport in metals by an electrochemical technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This practice gives a procedure for the evaluation of hydrogen uptake, permeation, and transport in metals using an electrochemical technique which was developed by Devanathan and Stachurski. While this practice is primarily intended for laboratory use, such measurements have been conducted in field or plant applications. Therefore, with proper adaptations, this practice can also be applied to such situations. 1.2 This practice describes calculation of an effective diffusivity of hydrogen atoms in a metal and for distinguishing reversible and irreversible trapping. 1.3 This practice specifies the method for evaluating hydrogen uptake in metals based on the steady-state hydrogen flux. 1.4 This practice gives guidance on preparation of specimens, control and monitoring of the environmental variables, test procedures, and possible analyses of results. 1.5 This practice can be applied in principle to all metals and alloys which have a high solubility for hydrogen, and for which the hydrogen permeation is ...

  1. Pyrite: A blender plugin for visualizing molecular dynamics simulations using industry-standard rendering techniques.

    Science.gov (United States)

    Rajendiran, Nivedita; Durrant, Jacob D

    2018-05-05

    Molecular dynamics (MD) simulations provide critical insights into many biological mechanisms. Programs such as VMD, Chimera, and PyMOL can produce impressive simulation visualizations, but they lack many advanced rendering algorithms common in the film and video-game industries. In contrast, the modeling program Blender includes such algorithms but cannot import MD-simulation data. MD trajectories often require many gigabytes of memory/disk space, complicating Blender import. We present Pyrite, a Blender plugin that overcomes these limitations. Pyrite allows researchers to visualize MD simulations within Blender, with full access to Blender's cutting-edge rendering techniques. We expect Pyrite-generated images to appeal to students and non-specialists alike. A copy of the plugin is available at http://durrantlab.com/pyrite/, released under the terms of the GNU General Public License Version 3. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. On the compatible weakly nonlocal Poisson brackets of hydrodynamic type

    Directory of Open Access Journals (Sweden)

    Andrei Ya. Maltsev

    2002-01-01

    of hydrodynamic type (Ferapontov brackets and the corresponding integrable hierarchies. We show that, under the requirement of the nondegeneracy of the corresponding “first” pseudo-Riemannian metric g(0 νμ and also some nondegeneracy requirement for the nonlocal part, it is possible to introduce a “canonical” set of “integrable hierarchies” based on the Casimirs, momentum functional and some “canonical Hamiltonian functions.” We prove also that all the “higher” “positive” Hamiltonian operators and the “negative” symplectic forms have the weakly nonlocal form in this case. The same result is also true for “negative” Hamiltonian operators and “positive” symplectic structures in the case when both pseudo-Riemannian metrics g(0 νμ and g(1 νμ are nondegenerate.

  3. Psychovisual masks and intelligent streaming RTP techniques for the MPEG-4 standard

    Science.gov (United States)

    Mecocci, Alessandro; Falconi, Francesco

    2003-06-01

    In today multimedia audio-video communication systems, data compression plays a fundamental role by reducing the bandwidth waste and the costs of the infrastructures and equipments. Among the different compression standards, the MPEG-4 is becoming more and more accepted and widespread. Even if one of the fundamental aspects of this standard is the possibility of separately coding video objects (i.e. to separate moving objects from the background and adapt the coding strategy to the video content), currently implemented codecs work only at the full-frame level. In this way, many advantages of the flexible MPEG-4 syntax are missed. This lack is due both to the difficulties in properly segmenting moving objects in real scenes (featuring an arbitrary motion of the objects and of the acquisition sensor), and to the current use of these codecs, that are mainly oriented towards the market of DVD backups (a full-frame approach is enough for these applications). In this paper we propose a codec for MPEG-4 real-time object streaming, that codes separately the moving objects and the scene background. The proposed codec is capable of adapting its strategy during the transmission, by analysing the video currently transmitted and setting the coder parameters and modalities accordingly. For example, the background can be transmitted as a whole or by dividing it into "slightly-detailed" and "highly detailed" zones that are coded in different ways to reduce the bit-rate while preserving the perceived quality. The coder can automatically switch in real-time, from one modality to the other during the transmission, depending on the current video content. Psychovisual masks and other video-content based measurements have been used as inputs for a Self Learning Intelligent Controller (SLIC) that changes the parameters and the transmission modalities. The current implementation is based on the ISO 14496 standard code that allows Video Objects (VO) transmission (other Open Source Codes

  4. Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets

    Directory of Open Access Journals (Sweden)

    M S Kannan

    2015-01-01

    Full Text Available Aim: The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope study of the Brackets after Frictional evaluation. Materials and Methods: Two types of self-ligating esthetic brackets, Damon clear (Ormco made of fully ceramic and Opal (Ultradent Products, USA and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek and Damon 3 (Ormco both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot. Results: The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets. For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05 than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets generated smaller amount of frictional forces when compared with Damon clear and

  5. Two-loop renormalization in the standard model, part II. Renormalization procedures and computational techniques

    Energy Technology Data Exchange (ETDEWEB)

    Actis, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Passarino, G. [Torino Univ. (Italy). Dipt. di Fisica Teorica; INFN, Sezione di Torino (Italy)

    2006-12-15

    In part I general aspects of the renormalization of a spontaneously broken gauge theory have been introduced. Here, in part II, two-loop renormalization is introduced and discussed within the context of the minimal Standard Model. Therefore, this paper deals with the transition between bare parameters and fields to renormalized ones. The full list of one- and two-loop counterterms is shown and it is proven that, by a suitable extension of the formalism already introduced at the one-loop level, two-point functions suffice in renormalizing the model. The problem of overlapping ultraviolet divergencies is analyzed and it is shown that all counterterms are local and of polynomial nature. The original program of 't Hooft and Veltman is at work. Finite parts are written in a way that allows for a fast and reliable numerical integration with all collinear logarithms extracted analytically. Finite renormalization, the transition between renormalized parameters and physical (pseudo-)observables, are discussed in part III where numerical results, e.g. for the complex poles of the unstable gauge bosons, are shown. An attempt is made to define the running of the electromagnetic coupling constant at the two-loop level. (orig.)

  6. Standard Test Methods for Total Normal Emittance of Surfaces Using Inspection-Meter Techniques

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1971-01-01

    1.1 These test methods cover determination of the total normal emittance (Note) of surfaces by means of portable, inspection-meter instruments. Note 1—Total normal emittance (εN) is defined as the ratio of the normal radiance of a specimen to that of a blackbody radiator at the same temperature. The equation relating εN to wavelength and spectral normal emittance [εN (λ)] is where: L b(λ, T) = Planck's blackbody radiation function = c1π −1λ−5(ec2/λT − 1)−1, c1 = 3.7415 × 10−16 W·m 2, c2 = 1.4388 × 10−2 m·K, T = absolute temperature, K, λ = wavelength, m, Lb(λ, T)dλ = Δπ −1T4, and Δ = Stefan-Boltzmann constant = 5.66961 × 10 −8 W·m2·K−4 1.2 These test methods are intended for measurements on large surfaces when rapid measurements must be made and where a nondestructive test is desired. They are particularly useful for production control tests. 1.3 The values stated in SI units are to be regarded as standard. No other units of measu...

  7. Watermarking Techniques Using Least Significant Bit Algorithm for Digital Image Security Standard Solution- Based Android

    Directory of Open Access Journals (Sweden)

    Ari Muzakir

    2017-05-01

    Full Text Available Ease of deployment of digital image through the internet has positive and negative sides, especially for owners of the original digital image. The positive side of the ease of rapid deployment is the owner of that image deploys digital image files to various sites in the world address. While the downside is that if there is no copyright that serves as protector of the image it will be very easily recognized ownership by other parties. Watermarking is one solution to protect the copyright and know the results of the digital image. With Digital Image Watermarking, copyright resulting digital image will be protected through the insertion of additional information such as owner information and the authenticity of the digital image. The least significant bit (LSB is one of the algorithm is simple and easy to understand. The results of the simulations carried out using android smartphone shows that the LSB watermarking technique is not able to be seen by naked human eye, meaning there is no significant difference in the image of the original files with images that have been inserted watermarking. The resulting image has dimensions of 640x480 with a bit depth of 32 bits. In addition, to determine the function of the ability of the device (smartphone in processing the image using this application used black box testing. 

  8. Qualitative and quantitative evaluation of human dental enamel after bracket debonding: a noncontact three-dimensional optical profilometry analysis.

    Science.gov (United States)

    Ferreira, Fabiano G; Nouer, Darcy F; Silva, Nelson P; Garbui, Ivana U; Correr-Sobrinho, Lourenço; Nouer, Paulo R A

    2014-09-01

    The aim of this study was to undertake a qualitative and quantitative evaluation of changes on enamel surfaces after debonding of brackets followed by finishing procedures, using a high-resolution three-dimensional optical profiler and to investigate the accuracy of the technique. The labial surfaces of 36 extracted upper central incisors were examined. Before bonding, the enamel surfaces were subjected to profilometry, recording four amplitude parameters. Brackets were then bonded using two types of light-cured orthodontic adhesive: composite resin and resin-modified glass ionomer cement. Finishing was performed by three different methods: pumice on a rubber cup, fine and ultrafine aluminum oxide discs, and microfine diamond cups followed by silicon carbide brushes. The samples were subsequently re-analyzed by profilometry. Wilcoxon signed-rank test, Kruskal-Wallis test (p enamel roughness when diamond cups followed by silicon carbide brushes were used to finish surfaces that had remnants of resin-modified glass ionomer adhesive and when pumice was used to finish surfaces that had traces of composite resin. Enamel loss was minimal. The 3D optical profilometry technique was able to provide accurate qualitative and quantitative assessment of changes on the enamel surface after debonding. Morphological changes in the topography of dental surfaces, especially if related to enamel loss and roughness, are of considerable clinical importance. The quantitative evaluation method used herein enables a more comprehensive understanding of the effects of orthodontic bonding on teeth.

  9. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

    Energy Technology Data Exchange (ETDEWEB)

    Campo B, X.; Mendez V, R.; Embid S, M. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Sanz G, J., E-mail: xandra.campo@ciemat.es [Universidad Nacional de Educacion a Distancia, Escuela Tecnica Superior de Ingenieros Industriales, C. Juan del Rosal 12, 28040 Madrid (Spain)

    2014-08-15

    Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with {sup 241}Am-Be (185 GBq) and {sup 252}Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the {sup 252}Cf source. This source predominates and the effect of the {sup 241}Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

  10. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

    International Nuclear Information System (INIS)

    Campo B, X.; Mendez V, R.; Embid S, M.; Vega C, H. R.; Sanz G, J.

    2014-08-01

    Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with 241 Am-Be (185 GBq) and 252 Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the 252 Cf source. This source predominates and the effect of the 241 Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

  11. Comparison of four different techniques to evaluate the elastic properties of phantom in elastography: is there a gold standard?

    Science.gov (United States)

    Oudry, Jennifer; Lynch, Ted; Vappou, Jonathan; Sandrin, Laurent; Miette, Véronique

    2014-10-07

    Elastographic techniques used in addition to imaging techniques (ultrasound, resonance magnetic or optical) provide new clinical information on the pathological state of soft tissues. However, system-dependent variation in elastographic measurements may limit the clinical utility of these measurements by introducing uncertainty into the measurement. This work is aimed at showing differences in the evaluation of the elastic properties of phantoms performed by four different techniques: quasi-static compression, dynamic mechanical analysis, vibration-controlled transient elastography and hyper-frequency viscoelastic spectroscopy. Four Zerdine® gel materials were tested and formulated to yield a Young's modulus over the range of normal and cirrhotic liver stiffnesses. The Young's modulus and the shear wave speed obtained with each technique were compared. Results suggest a bias in elastic property measurement which varies with systems and highlight the difficulty in finding a reference method to determine and assess the elastic properties of tissue-mimicking materials. Additional studies are needed to determine the source of this variation, and control for them so that accurate, reproducible reference standards can be made for the absolute measurement of soft tissue elasticity.

  12. Standardization of the Fricke gel dosimetry method and tridimensional dose evaluation using the magnetic resonance imaging technique

    International Nuclear Information System (INIS)

    Cavinato, Christianne Cobello

    2009-01-01

    This study standardized the method for obtaining the Fricke gel solution developed at IPEN. The results for different gel qualities used in the preparation of solutions and the influence of the gelatin concentration in the response of dosimetric solutions were compared. Type tests such as: dose response dependence, minimum and maximum detection limits, response reproducibility, among others, were carried out using different radiation types and the Optical Absorption (OA) spectrophotometry and Magnetic Resonance (MR) techniques. The useful dose ranges for Co 60 gamma radiation and 6 MeV photons are 0,4 to 30,0 Gy and 0,5 to 100,0 Gy , using OA and MR techniques, respectively. A study of ferric ions diffusion in solution was performed to determine the optimum time interval between irradiation and samples evaluation; until 2,5 hours after irradiation to obtain sharp MR images. A spherical simulator consisting of Fricke gel solution prepared with 5% by weight 270 Bloom gelatine (national quality) was developed to be used to three-dimensional dose assessment using the Magnetic Resonance Imaging (MRI) technique. The Fricke gel solution prepared with 270 Bloom gelatine, that, in addition to low cost, can be easily acquired on the national market, presents satisfactory results on the ease of handling, sensitivity, response reproducibility and consistency. The results confirm their applicability in the three-dimensional dosimetry using MRI technique. (author)

  13. The 'Pull' Technique for Removal of Peritoneal Dialysis Catheters: A Call for Re-Evaluation of Practice Standards.

    Science.gov (United States)

    Grieff, Marvin; Mamo, Elizabeth; Scroggins, Gina; Kurchin, Alexander

    2017-01-01

    ♦ BACKGROUND: The most commonly used peritoneal dialysis (PD) catheters have silicon tubing with attached Dacron cuffs. The current standard of care for PD catheter removal is by complete surgical dissection, withdrawing both the tubing and the cuffs. The intention is to avoid infection of any residual part of the catheter. We retrospectively analyzed our results with the alternative 'pull' technique, by which the silicon tube is pulled out, leaving the Dacron cuffs within the abdominal wall. This technique never gained popularity due to concern that the retained cuffs would get infected. ♦ METHODS: We reviewed our experience from an 18-month period, between January 2014 and June 2015. There were 46 catheter removals in 40 patients. All the catheters were of the double-cuffed coiled Tenckhoff type (Covidien, Dublin, Ireland). ♦ RESULTS: Of the 46 catheter removals by the 'pull' technique, there was only 1 case of retained cuff infection. ♦ CONCLUSIONS: The 'pull' technique is a safe method for Tenckhoff catheter removal with low risk of infection. We strongly recommend it as the procedure of choice. Copyright © 2017 International Society for Peritoneal Dialysis.

  14. [The standard implantation of a total hip prosthesis via two incisions (the Yale Technique)].

    Science.gov (United States)

    Kipping, Robert

    2009-09-01

    Implantation of a total hip endoprosthesis with minimal trauma to the soft tissue. The need for visual aids (e.g., navigation or X-rays) during the procedure is frequently avoided. All kinds of coxarthrosis for every age group, for every variation of bone construction, and even in obese patients. Extremely dysplastic hip joints involving the development of a secondary socket and the necessity of reconstruction of the acetabular socket (e.g., in the Harris method). Using a fixed lateral position, a small entry incision is made between the tensor fasciae latae and the sartorius muscles and the prosthesis socket is put into place. Via a second dorsal incision, after stripping the exterior rotators, the prosthesis stem and ball are implanted and the two parts of the prosthesis are attached. Full weight bearing allowed immediately. A luxation prophylaxis, in the form of a self-developed hip bodice (the so-called Yale bandage), is used until the end of the 4th postoperative week. Discharge from hospital is possible after just a few days. Upon discharge, the patient is sent to a rehabilitation facility, either as a resident or as an outpatient, for approximately 3 weeks. Return to the workplace, with only light physical activity, is possible once the wound has healed completely; this could be as soon as 14 days after the operation. Checkups are made after 4 weeks, 6 months, 1 year and then every year; these checkups include a full examination, X-rays and laboratory tests. Full exposure to sport or heavy manual labor is usually approved after the 6-month checkup. Between October 2004 and April 2006, a total of 221 patients underwent surgery using this new technique (of these 15 patients underwent two-stage bilateral hip joint replacements). Patients were followed up for a minimum of 12 months and a maximum of 30 months. The Harris Hip Score improved from an average of 45.25 preoperatively to 96.4 postoperatively.

  15. Effects of six different preventive treatments on the shear bond strength of orthodontic brackets: in vitro study

    Directory of Open Access Journals (Sweden)

    Gianguido Cossellu

    2015-01-01

    Full Text Available Objective: The aim of this study is to evaluate the effect of six different prophylactic agents on shear bond strength (SBS of orthodontic brackets. Materials and methods: One hundred twenty-six freshly extracted mandibular bovine incisors were used. Teeth were randomly divided into 7 equal groups (18 per group as follows: group-1 served as control with no pre-treatment; group-2 enamel treated with fluoride varnish (Fluor Protector, Ivoclar Vivadent; group-3 containing casein-phosphopeptide–amorphous calcium-phosphate (CPP–ACP paste (GC Tooth Mousse, RECALDENT™; group-4 with ozone (HealOzone, Kavo; group-5 with glycine powder (Perio Flow, EMS; group-6 with hydroxyapatite powder 99.5% (Coswell S.p.A.; group-7 with a toothpaste made of hydroxyapatite nanocrystals (BioRepair® Plus, Coswell S.p.A. Brackets were all bonded using the same technique with transbond XT (3 M Unitek, Monrovia, CA. All the bonded specimens were stored for 24 h in deionized water (37 °C and subjected to thermal cycling for 1000 cycles. The SBS was measured with an Instron Universal Testing machine and the adhesive remnant was assessed with the adhesive remnant index (ARI using a stereomicroscope at 10× magnification. Results: Statistical differences (ANOVA were found among the seven investigated groups (F = 12.226, p < 0.001. SBS of groups 2, 5 and 6 were significantly lower than the control group (p < 0.05. ARI scores (chi-square test were correlated with the differences of SBS values. Conclusion: CPP–ACP paste, ozone or BioRepair® did not compromise on bracket bond strength. Fluoride, glycine or hydroxyapatite significantly decreased the SBS; only the fluoride group showed significant clinically low (<6 MPa SBS values.

  16. Opening and closure forces of sliding mechanisms of different self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Paola GANDINI

    2013-06-01

    Full Text Available Self-ligating brackets engage the wire by means of a slide mechanism. Forces that have to be applied to open and close the sliding mechanism of brackets are still unknown. Objective The aim of this study was to measure and compare the opening and closure forces of different self-ligating brackets. Material and Methods Three different stainless steel self-ligating brackets (Carriere LX, Ortho Organizers; F1000, Leone; Damon Q, Ormco were tested. For each different bracket, 20 maxillary right central incisors and 20 mandibular right central incisors were used. Opening and closure forces were measured using an Instron Universal Testing Machine. Statistical analysis was performed and ANOVA and Tukey tests were carried out. Results Opening forces were registered between 1.1 N and 5.6 N, whereas closure forces were recorded between 1.57 N and 4.87 N. Significant differences were detected among the different brackets and between the two prescriptions tested. Conclusion The knowledge of different opening and closure forces of self-ligating brackets can help the orthodontist in the clinical management of these devices.

  17. Comparative study of torque expression among active and passive self-ligating and conventional brackets

    Directory of Open Access Journals (Sweden)

    Érika Mendonça Fernandes Franco

    2015-12-01

    Full Text Available Abstract Objective: The aim of this study was to compare torque expression in active and passive self-ligating and conventional brackets. Methods: A total of 300 segments of stainless steel wire 0.019 x 0.025-in and six different brands of brackets (Damon 3MX, Portia, In-Ovation R, Bioquick, Roth SLI and Roth Max were used. Torque moments were measured at 12°, 24°, 36° and 48°, using a wire torsion device associated with a universal testing machine. The data obtained were compared by analysis of variance followed by Tukey test for multiple comparisons. Regression analysis was performed by the least-squares method to generate the mathematical equation of the optimal curve for each brand of bracket. Results: Statistically significant differences were observed in the expression of torque among all evaluated bracket brands in all evaluated torsions (p < 0.05. It was found that Bioquick presented the lowest torque expression in all tested torsions; in contrast, Damon 3MX bracket presented the highest torque expression up to 36° torsion. Conclusions: The connection system between wire/bracket (active, passive self-ligating or conventional with elastic ligature seems not to interfere in the final torque expression, the latter being probably dependent on the interaction between the wire and the bracket chosen for orthodontic mechanics.

  18. Actual versus theoretical torsional play in conventional and self-ligating bracket systems

    DEFF Research Database (Denmark)

    Dalstra, Michel; Eriksen, Henrik; Bergamini, Chiara

    2015-01-01

    Abstract Objective: The aim of this study was to assess the amount of torsional play in 32 commercially available self-ligating and conventional 0·018-inch and 0·022-inch bracket systems in relation to 0·017×0·022-inch and 0·019×0·025-inch stainless steel wires, respectively, and compare the resu......Abstract Objective: The aim of this study was to assess the amount of torsional play in 32 commercially available self-ligating and conventional 0·018-inch and 0·022-inch bracket systems in relation to 0·017×0·022-inch and 0·019×0·025-inch stainless steel wires, respectively, and compare...... and particularly in relation to the passive self-ligating brackets. The play ranged from 19·8 to 36·1° of play for the most imprecise bracket system. Conclusions: The result does not favour the use of self-ligating brackets when focussing on torque control. The actual play is larger due to oversized slots...... and the inability of self-ligation brackets to press the archwire into the bottom of the slot. In conventional brackets, the initial torque moment is generated by the steel ligatures pressing the arch wire against the bottom of the slot. The oversize of the slot is thus less critical in relation to the conventional...

  19. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kajan, Zahra Dalili; Alizadeh, Ahmad; Hemmaty, Yasmin Babael; Roushan, Zahra Atrkar; Khademi, Jalil

    2015-01-01

    This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1-weighted images, fast spin-echo T2-weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires

  20. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kajan, Zahra Dalili; Alizadeh, Ahmad; Hemmaty, Yasmin Babael; Roushan, Zahra Atrkar; Khademi, Jalil [Guilan University of Medical Sciences, Rasht (Iran, Islamic Republic of)

    2015-09-15

    This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1-weighted images, fast spin-echo T2-weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires.

  1. A comparative study of metal artifacts from common metal orthodontic brackets in magnetic resonance imaging

    Science.gov (United States)

    Khademi, Jalil; Alizadeh, Ahmad; Babaei Hemmaty, Yasamin; Atrkar Roushan, Zahra

    2015-01-01

    Purpose This study was performed to compare the metal artifacts from common metal orthodontic brackets in magnetic resonance imaging. Materials and Methods A dry mandible with 12 intact premolars was prepared, and was scanned ten times with various types of brackets: American, 3M, Dentaurum, and Masel orthodontic brackets were used, together with either stainless steel (SS) or nickel titanium (NiTi) wires. Subsequently, three different sequences of coronal and axial images were obtained: spin-echo T1-weighted images, fast spin-echo T2-weighted images, and fluid-attenuated inversion recovery images. In each sequence, the two sequential axial and coronal images with the largest signal-void area were selected. The largest diameters of the signal voids in the direction of the X-, Y-, and Z-axes were then measured twice. Finally, the mean linear values associated with different orthodontic brackets were analyzed using one-way analysis of variation, and the results were compared using the independent t-test to assess whether the use of SS or NiTi wires had a significant effect on the images. Results Statistically significant differences were only observed along the Z-axis among the four different brands of orthodontic brackets with SS wires. A statistically significant difference was observed along all axes among the brackets with NiTi wires. A statistically significant difference was found only along the Z-axis between nickel-free and nickel-containing brackets. Conclusion With respect to all axes, the 3M bracket was associated with smaller signal-void areas. Overall, the 3M and Dentaurum brackets with NiTi wires induced smaller artifacts along all axes than those with SS wires. PMID:26389058

  2. Russian Language Development Assessment as a Standardized Technique for Assessing Communicative Function in Children Aged 3–9 Years

    Directory of Open Access Journals (Sweden)

    Prikhoda N.A.,

    2016-10-01

    Full Text Available The article describes the Russian Language Development Assessment, a standardized individual diagnostic tool for children aged from 3 to 9 that helps to assess the following components of a child’s communicative function: passive vocabulary, expressive vocabulary, knowledge of semantic constructs with logical, temporal and spatial relations, passive perception and active use of syntactic and morphological features of words in a sentence, active and passive phonological awareness, active and passive knowledge of syntactic structures and categories. The article provides descriptions of content and diagnostic procedures for all 7 subtests included in the assessment (Passive Vocabulary, Active Vocabulary, Linguistic Operators, Sentence structure, Word Structure, Phonology, Sentence Repetition. Basing on the data collected in the study that involved 86 first- graders of a Moscow school, the article analyzes the internal consistency and construct validity of each subtest of the technique. It concludes that the Russian Language Development Assessment technique can be of much use both in terms of diagnostic purposes and in supporting children with ASD taking into account the lack of standardized tools for language and speech development assessment in Russian and the importance of this measure in general.

  3. A comparative study of standard vs. high definition colonoscopy for adenoma and hyperplastic polyp detection with optimized withdrawal technique.

    Science.gov (United States)

    East, J E; Stavrindis, M; Thomas-Gibson, S; Guenther, T; Tekkis, P P; Saunders, B P

    2008-09-15

    Colonoscopy has a known miss rate for polyps and adenomas. High definition (HD) colonoscopes may allow detection of subtle mucosal change, potentially aiding detection of adenomas and hyperplastic polyps. To compare detection rates between HD and standard definition (SD) colonoscopy. Prospective, cohort study with optimized withdrawal technique (withdrawal time >6 min, antispasmodic, position changes, re-examining flexures and folds). One hundred and thirty patients attending for routine colonoscopy were examined with either SD (n = 72) or HD (n = 58) colonoscopes. Groups were well matched. Sixty per cent of patients had at least one adenoma detected with SD vs. 71% with HD, P = 0.20, relative risk (benefit) 1.32 (95% CI 0.85-2.04). Eighty-eight adenomas (mean +/- standard deviation 1.2 +/- 1.4) were detected using SD vs. 93 (1.6 +/- 1.5) with HD, P = 0.12; however more nonflat, diminutive (9 mm) hyperplastic polyps was 7% (0.09 +/- 0.36). High definition did not lead to a significant increase in adenoma or hyperplastic polyp detection, but may help where comprehensive lesion detection is paramount. High detection rates appear possible with either SD or HD, when using an optimized withdrawal technique.

  4. Comparison of frictional forces between aesthetic orthodontic coated wires and self-ligation brackets

    OpenAIRE

    Kim, Yunmi; Cha, Jung-Yul; Hwang, Chung-Ju; Yu, Hyung Seog; Tahk, Seon Gun

    2014-01-01

    Objective The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. Methods 0.016-inch nickel titanium (NiTi) wires and 0.017 × 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0°, 5°, and 10°. Upper maxillary premolar brackets (Clippy-C®) with a 0.022-inch slot were selected for the study and a te...

  5. IN VITRO Cr(VI SPECIATION IN SYNTHETIC SALIVA AFTER RELEASING FROM ORTHODONTIC BRACKETS USING SILICA-APTES SEPARATION AND GF AAS DETERMINATION

    Directory of Open Access Journals (Sweden)

    Maciel S. Luz

    Full Text Available A method for Cr(VI speciation in synthetic saliva after releasing from orthodontic brackets, using silica nanoparticles organofunctionalized with (3-aminopropyltriethoxysilane (APTES for Cr(III/Cr(VI separation and GF AAS determination is proposed. Under the optimized conditions, Cr(VI speciation was performed using 150 mg of silica organofunctionalized with 2.0% (v v-1 of APTES at pH 8. It was observed different sensitivity when calibrations of GF AAS were performed using Cr(III or Cr(VI as standard solutions. Consequently, calibrations using stoichiometric mixtures (Cr(III + Cr(VI were used for total Cr determination and calibration using Cr(VI was used only for the determination of this specie. The reliability of the proposed silica-APTES separation procedure and GF AAS determination was checked by addition of both species in synthetic saliva. Recoveries ranging from 97 to 110% were obtained. The repeatability, based on the relative standard deviation (RSD inter days was less than 6%. A corrosion test was carried out on 20 orthodontic brackets from two different models, after immersion in synthetic saliva (pH=6.0 at 37 °C with agitation (125 rpm for 24 h. It was observed that about 40% of the total chromium released from the analyzed orthodontic brackets was Cr(VI.

  6. Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Ruo-qiao Han

    2016-01-01

    Full Text Available Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p<0.05, but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.

  7. Effect of sodium bicarbonate air abrasive polishing on attrition and surface micromorphology of ceramic and stainless steel brackets.

    Science.gov (United States)

    Parmagnani, Eduardo Augusto; Basting, Roberta Tarkany

    2012-03-01

    To evaluate the frictional resistance of ceramic and metal brackets using rectangular stainless steel orthodontic wires before and after using sodium bicarbonate air abrasive polishing and to evaluate the surface micromorphology of these brackets by means of scanning electron microscopy. Two commercial brands of metal brackets and two commercial brands of ceramic brackets were evaluated. The specimens were divided into eight groups (n  =  10) according to brackets and the application or not of sodium bicarbonate airborne particle abrasion for 10 seconds. A device adapted to a universal testing machine was used to simulate the movement of retraction in sliding mechanics, measuring the traction force needed to slide 10 mm of the wire over the test specimen brackets. The test speed was 5 mm/min. The data were analyzed by two-way analysis of variance (ANOVA) and Tukey test. There was higher frictional resistance after airborne particle abrasion irrespective of the type of bracket (P < .05). One of the ceramic brackets showed higher frictional resistance before and after airborne application than the other metal and ceramic brackets. The micromorphologic analysis showed that airborne particle abrasion caused alterations on the metal bracket surfaces. It may be concluded that it is not recommended to apply airborne particle abrasion on the slots of ceramic or metal brackets.

  8. Twin - Arch technique. Revival of the "edgewise -Technique"?

    Directory of Open Access Journals (Sweden)

    Jacob Karp

    2012-01-01

    The SNB – Bracket brings a new dimension into the orthodontic world which is most apparent in extraction cases. Its Teflon – like material has a very low friction coefficient thus, reducing the treatment time considerably. Through the use of low dimensioned arch wires, the Twin – Arch Technique becomes a Light – wire system and simultaneously provides good anchorage and torque control.

  9. Resistance to Sliding in Clear and Metallic Damon 3 and Conventional Edgewise Brackets: an In vitro Study

    Science.gov (United States)

    Karim Soltani, Mohammad; Golfeshan, Farzaneh; Alizadeh, Yoones; Mehrzad, Jabraiel

    2015-01-01

    Statement of the Problem Frictional forces are considered as important counterforce to orthodontic tooth movement. It is claimed that self-ligating brackets reduce the frictional forces. Purpose The aim of this study was to compare the resistance to sliding in metallic and clear Damon brackets with the conventional brackets in a wet condition. Materials and Method The samples included 4 types of brackets; metallic and clear Damon brackets and metallic and clear conventional brackets (10 brackets in each group). In this study, stainless steel wires sized 0.019×0.025 were employed and the operator’s saliva was used to simulate the conditions of oral cavity. The tidy-modified design was used for simulation of sliding movement. The resistance to sliding and static frictional forces was measured by employing Testometric machine and load cell. Results The mean (±SD) of resistance to sliding was 194.88 (±26.65) and 226.62 (±39.9) g in the esthetic and metallic Damon brackets, while these values were 187.81(±27.84) and 191.17(±66.68) g for the clear and metallic conventional brackets, respectively. Static frictional forces were 206.4(±42.45) and 210.38(±15.89) g in the esthetic and metallic Damon brackets and 220.63(±49.29) and 215.13(±62.38) g in the clear and metallic conventional brackets. According to two-way ANOVA, no significant difference was observed between the two bracket materials (clear and metal) and the two types of bracket (self-ligating versus conventional) regarding resistance to sliding (p= 0.17 and p= 0.23, respectively) and static frictional forces (p= 0.55 and p= 0.96, respectively). Conclusion Neither the type of bracket materials nor their type of ligation made difference in resistance to sliding and static friction. PMID:26106630

  10. Comparison between two methods for resin removing after bracket debonding

    Directory of Open Access Journals (Sweden)

    Rodrigo De Marchi

    2012-12-01

    Full Text Available OBJECTIVE: The aim of this study was to assess - using scanning electron microscopy (SEM - the effectiveness of two abrasive discs, one made from silicon and one from aluminum oxide, in removing adhesive remnants (AR after debonding orthodontic brackets. METHODS: Ten randomly selected bovine teeth were used, i.e., 2 in the control group, and the other 8 divided into two groups, which had orthodontic brackets bonded to their surface with Concise Orthodontic Adhesive (3M. The following methods were employed - in one single step - to remove AR after debracketing: Group A, Optimize discs (TDV and Group B, Onegloss discs (Shofu, used at low speed. After removing the AR with the aforementioned methods, the teeth were prepared to undergo SEM analysis, and photographs were taken of the enamel surface with 50x magnification. Six examiners evaluated the photographs applying the Zachrisson and Årtun enamel surface index (ESI system (1979. RESULTS: Group A exhibited minor scratches on the enamel surface as well as some AR in some of the photographs, while Group B showed a smoother surface, little or no AR and some abrasion marks in the photographs. No statistically significant differences were found between the two methods and the control group. CONCLUSIONS: The two abrasive discs were effective in removing the AR after bracket debonding in one single step.OBJETIVO: o objetivo deste trabalho foi avaliar, por microscopia eletrônica de varredura, a eficácia de dois discos abrasivos de silicone e óxido de alumínio para a remoção da resina remanescente após a descolagem de braquetes ortodônticos. MÉTODOS: foram utilizados 10 dentes bovinos selecionados aleatoriamente, sendo 2 para o grupo controle e os demais divididos em dois grupos, os quais receberam colagem de braquetes ortodônticos com resina ortodôntica Concise (3M. Os métodos de remoção da resina após a descolagem dos acessórios ortodônticos em apenas uma etapa foram: Grupo A - disco

  11. Equal-Time and Equal-Space Poisson Brackets of the N -Component Coupled NLS Equation

    International Nuclear Information System (INIS)

    Zhou Ru-Guang; Li Pei-Yao; Gao Yuan

    2017-01-01

    Two Poisson brackets for the N-component coupled nonlinear Schrödinger (NLS) equation are derived by using the variantional principle. The first one is called the equal-time Poisson bracket which does not depend on time but only on the space variable. Actually it is just the usual one describing the time evolution of system in the traditional theory of integrable Hamiltonian systems. The second one is equal-space and new. It is shown that the spatial part of Lax pair with respect to the equal-time Poisson bracket and temporal part of Lax pair with respect to the equal-space Poisson bracket share the same r-matrix formulation. These properties are similar to that of the NLS equation. (paper)

  12. Bracket formulations and energy- and helicity-preserving numerical methods for incompressible two-phase flows

    Science.gov (United States)

    Suzuki, Yukihito

    2018-03-01

    A diffuse interface model for three-dimensional viscous incompressible two-phase flows is formulated within a bracket formalism using a skew-symmetric Poisson bracket together with a symmetric negative semi-definite dissipative bracket. The budgets of kinetic energy, helicity, and enstrophy derived from the bracket formulations are properly inherited by the finite difference equations obtained by invoking the discrete variational derivative method combined with the mimetic finite difference method. The Cahn-Hilliard and Allen-Cahn equations are employed as diffuse interface models, in which the equalities of densities and viscosities of two different phases are assumed. Numerical experiments on the motion of periodic arrays of tubes and those of droplets have been conducted to examine the properties and usefulness of the proposed method.

  13. Research and analysis on response characteristics of bracket-line coupling system under wind load

    Science.gov (United States)

    Jiayu, Zhao; Qing, Sun

    2018-01-01

    In this paper, a three-dimensional finite element model of bracket-line coupling system is established based on ANSYS software. Using the wind velocity time series which is generated by MATLAB as a power input, by comparing and analyzing the influence of different wind speeds and different wind attack angles, it is found that when 0 degree wind acts on the structure, wires have a certain damping effect in the bracket-line coupling system and at the same wind speed, the 90 degree direction is the most unfavorable wind direction for the whole structure according to the three kinds of angle wind calculated at present. In the bracket-line coupling system, the bracket structure is more sensitive to the increase of wind speed while the conductors are more sensitive to the change of wind attack angle.

  14. Rebonding performance of different ceramic brackets conditioned with a new silane coupling agent.

    Science.gov (United States)

    Falkensammer, Frank; Jonke, Erwin; Bertl, Michael; Freudenthaler, Josef; Bantleon, Hans Peter

    2013-02-01

    The objective of this study was to investigate the rebonding effect of a new silane coupling agent on various ceramic brackets bonded to ceramic specimen. Different ceramic brackets (Fascination 2, Clarity SL, and In-OvationC) were assigned to three groups: rebonding with new silane coupling agent, rebonding with conventional silane coupling agent, or regular bonding as control (n = 16). Bracket adhesion was calculated with a shear test in a universal testing machine. The bracket-composite-ceramic interface was evaluated using the adhesive remnant index score. One-way analysis of variance was applied for inferential statistics. Rebonding with the new silane coupling agent resulted in high shear bond strengths (SBSs; mean values: 37.44-41.24 MPa) and ceramic specimen fractures. Rebonding with the conventional silane coupling agent resulted in significantly (P silane coupling should be debonded cautiously using alternative debonding methods.

  15. High-dynamic-range microscope imaging based on exposure bracketing in full-field optical coherence tomography.

    Science.gov (United States)

    Leong-Hoi, Audrey; Montgomery, Paul C; Serio, Bruno; Twardowski, Patrice; Uhring, Wilfried

    2016-04-01

    By applying the proposed high-dynamic-range (HDR) technique based on exposure bracketing, we demonstrate a meaningful reduction in the spatial noise in image frames acquired with a CCD camera so as to improve the fringe contrast in full-field optical coherence tomography (FF-OCT). This new signal processing method thus allows improved probing within transparent or semitransparent samples. The proposed method is demonstrated on 3 μm thick transparent polymer films of Mylar, which, due to their transparency, produce low contrast fringe patterns in white-light interference microscopy. High-resolution tomographic analysis is performed using the technique. After performing appropriate signal processing, resulting XZ sections are observed. Submicrometer-sized defects can be lost in the noise that is present in the CCD images. With the proposed method, we show that by increasing the signal-to-noise ratio of the images, submicrometer-sized defect structures can thus be detected.

  16. Normal forms of dispersive scalar Poisson brackets with two independent variables

    Science.gov (United States)

    Carlet, Guido; Casati, Matteo; Shadrin, Sergey

    2018-03-01

    We classify the dispersive Poisson brackets with one dependent variable and two independent variables, with leading order of hydrodynamic type, up to Miura transformations. We show that, in contrast to the case of a single independent variable for which a well-known triviality result exists, the Miura equivalence classes are parametrised by an infinite number of constants, which we call numerical invariants of the brackets. We obtain explicit formulas for the first few numerical invariants.

  17. Comparison of clinical bracket point registration with 3D laser scanner and coordinate measuring machine

    OpenAIRE

    Nouri,Mahtab; Farzan,Arash; Baghban,Ali Reza Akbarzadeh; Massudi,Reza

    2015-01-01

    OBJECTIVE: The aim of the present study was to assess the diagnostic value of a laser scanner developed to determine the coordinates of clinical bracket points and to compare with the results of a coordinate measuring machine (CMM). METHODS: This diagnostic experimental study was conducted on maxillary and mandibular orthodontic study casts of 18 adults with normal Class I occlusion. First, the coordinates of the bracket points were measured on all casts by a CMM. Then, the three-dimensional ...

  18. Technical report for quality requirements establishment of in-chimney bracket

    International Nuclear Information System (INIS)

    Kim, Kwan Hyun

    2000-06-01

    This technical report provides the methods on how to sustain the items of experimental materials, nuclear fuel on examination, ect. This report applies to the quality assurance(QA) programmes of the design, fabrication in-chimney bracket.The organization having overall responsibility for the nuclear power item design, preservation, fabrication shall be described in this report in each stage of chimney bracket fabrication project

  19. Demonstration of a 10 V programmable Josephson voltage standard system based on a multi-chip technique

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, T; Sasaki, H; Yamamori, H; Shoji, A [National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)], E-mail: yamada-takahiro@aist.go.jp

    2008-03-01

    We have demonstrated a programmable Josephson voltage standard (PJVS) operation up to 10.84 V using a multi-chip technique. We combined two PJVS chips fabricated using NbN/(TiN{sub x}/NbN){sub 2} junction technology. Each PJVS chip was mounted on a single chip carrier using bonding wire, and the two chip carriers were connected by a simple Cu lead wire, and mounted on a cryocooler. High-precision measurements confirmed flat voltage steps for all 22 cells, with a peak-to-peak variation of 100 nV and wide margins of at least 0.35 mA. We also confirmed the stability of the voltage steps in spite of a temperature and RF frequency variation of {+-} 0.1 K and {+-} 0.1 GHz, respectively.

  20. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Rodrigo Hitoshi Higa

    Full Text Available ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM, active (In-Ovation RTM and passive (Damon 3MXTM self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi wires (MorelliTM and GACTM, in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces.

  1. Effect of Argon Laser on Enamel Demineralization around Orthodontic Brackets: An In Vitro Study.

    Directory of Open Access Journals (Sweden)

    Amirfarhang Miresmaeili

    2014-08-01

    Full Text Available This study was designed to evaluate the effect of argon laser irradiation on development and progress of enamel demineralization around orthodontic brackets.Fifty caries-free, intact human premolars were randomly assigned to one of the following five equal groups: Groups 1 (control and 2: The brackets were bonded using conventional halogen light for 40s and argon laser for 10s, respectively. Teeth in group 3 were lased with argon laser for 10s before bracket bonding with halogen light. Group 4 was the same as group 3 except that brackets were also bonded with argon laser. In group 5 samples were bonded conventionally, immersed in an artificial caries solution for two days and then irradiated for 10s with argon laser. All samples were subjected to demineralization by artificial caries solution for 10 days. After bracket removal, samples were buccolingually sectioned and evaluated by polarized light microscopy. Decalcified lesion depth in each section was measured by a trained examiner in a blind fashion. Data were analyzed in SPSS 14 using one-way ANOVA and Tukey's HSD post hoc test.The control group showed the greatest mean lesion depth while group 5 revealed the lowest. The laser-treated groups had significantly lower mean lesion depth compared with the control group (P<0.05 except for group 4 (P=0.192.Argon laser irradiation for 10s before or during bracket bonding can increase caries resistance of intact and demineralized enamel.

  2. Process qualification and testing of LENS deposited AY1E0125 D-bottle brackets.

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, Clinton J.; Smugeresky, John E. (Sandia National Labs, Livermore,CA); Jew, Michael (Sandia National Labs, Livermore,CA); Gill, David Dennis; Scheffel, Simon (Sandia National Labs, Livermore,CA)

    2006-11-01

    The LENS Qualification team had the goal of performing a process qualification for the Laser Engineered Net Shaping{trademark}(LENS{reg_sign}) process. Process Qualification requires that a part be selected for process demonstration. The AY1E0125 D-Bottle Bracket from the W80-3 was selected for this work. The repeatability of the LENS process was baselined to determine process parameters. Six D-Bottle brackets were deposited using LENS, machined to final dimensions, and tested in comparison to conventionally processed brackets. The tests, taken from ES1E0003, included a mass analysis and structural dynamic testing including free-free and assembly-level modal tests, and Haversine shock tests. The LENS brackets performed with very similar characteristics to the conventionally processed brackets. Based on the results of the testing, it was concluded that the performance of the brackets made them eligible for parallel path testing in subsystem level tests. The testing results and process rigor qualified the LENS process as detailed in EER200638525A.

  3. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets.

    Science.gov (United States)

    Higa, Rodrigo Hitoshi; Semenara, Nayara Thiago; Henriques, José Fernando Castanha; Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire

    2016-01-01

    The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM), active (In-Ovation RTM) and passive (Damon 3MXTM) self-ligating brackets. Two brands of stainless steel and nickel-titanium (NiTi) wires (MorelliTM and GACTM), in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey's tests. Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces.

  4. Comparison of static friction with self-ligating, modified slot design and conventional brackets

    Science.gov (United States)

    CASTRO, Raquel Morais; SMITH NETO, Perrin; HORTA, Martinho Campolina Rebello; PITHON, Matheus Melo; OLIVEIRA, Dauro Douglas

    2013-01-01

    Objective To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. Material and Methods The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. Results There was a significant difference (pwire size. The wire diameter influenced friction only when the brackets had a 10º angulation (pwire. Conclusion Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested. PMID:24037069

  5. Mechanical and topographic evaluation of esthetic brackets and its relation to frictional resistance

    Directory of Open Access Journals (Sweden)

    Vikram Pai

    2013-01-01

    Full Text Available Introduction: The purpose of this in-vitro study was to evaluate the frictional characteristics of conventional ceramic versus metal insert ceramic brackets in combination with stainless steel and Teflon-coated stainless steel archwires. Materials and Methods: Twenty brackets each, of ceramic and metal insert ceramic Maxillary canine preadjusted edgewise brackets 0.022 × 0.028 in slot and 20 archwires, each of stainless steel and Teflon-coated stainless steel (0.019 × 0.025 in were tested for frictional resistance. Friction was evaluated in a simulated Tidy′s design apparatus on universal testing machine. The kinetic friction data were analyzed using Student′s ′t′ test. The effects of surface characteristics on frictional resistance were qualitatively assessed using scanning electron microscope. Results: Metal insert ceramic brackets generated significantly lower kinetic frictional resistance than the conventional ceramic brackets with Teflon-coated stainless steel archwires (P < 0.001 as well as stainless steel archwires (P < 0.05. Conclusion: Metal insert ceramic bracket with stainless steel archwire is the best possible combination among the materials studied because it generated the least frictional resistance during simulated tooth movement.

  6. Comparison of static friction with self-ligating, modified slot design and conventional brackets.

    Science.gov (United States)

    Castro, Raquel Morais; Neto, Perrin Smith; Horta, Martinho Campolina Rebello; Pithon, Matheus Melo; Oliveira, Dauro Douglas

    2013-01-01

    To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. There was a significant difference (pstatic friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (pfriction (pstatic frictional force values between the conventional and self-ligating brackets tested.

  7. Evaluation of Static Friction of Polycrystalline Ceramic Brackets after Conditioning with Different Powers of Er:YAG Laser.

    Science.gov (United States)

    Arash, Valiollah; Javanmard, Saeed; Eftekhari, Zeinab; Rahmati-Kamel, Manouchehr; Bahadoram, Mohammad

    2015-01-01

    This research aimed to reduce the friction between the wire and brackets by Er:YAG laser. To measure the friction between the wires and brackets in 0° and 10° of wire angulations, 40 polycrystalline ceramic brackets (Hubit, South Korea) were divided into 8 study groups and irradiated by 100, 200, and 300 mj/s of Er:YAG laser power. Two groups of brackets were not irradiated. The friction between the wires and brackets was measured with universal testing machine (SANTAM) with a segment of .019 × .025 SS wire pulled out of the slot of bracket. ANOVA and t-test were used for analyzing the results. To evaluate the effect of the laser on surface morphology of the bracket, SEM evaluations were carried out. The mean frictional resistances between the brackets and wires with 0° of angulation by increasing the laser power decreased compared with control group, but, in 10° of angulation, the friction increased regardless of the laser power and was comparable to the friction of nonirradiated brackets. Furthermore, with each laser power, frictional resistance of brackets in 10° of angulation was significantly higher than 0° of angulation. These results were explained by SEM images too.

  8. Late effects of craniospinal irradiation for standard risk medulloblastoma in paediatric patients: A comparison of treatment techniques

    International Nuclear Information System (INIS)

    Leman, J.

    2016-01-01

    Background: Survival rates for standard risk medulloblastoma are favourable, but craniospinal irradiation (CSI) necessary to eradicate microscopic spread causes life limiting late effects. Aims: The aim of this paper is to compare CSI techniques in terms of toxicity and quality of life for survivors. Methods and materials: A literature search was conducted using synonyms of ‘medulloblastoma’, ’craniospinal’, ‘radiotherapy’ and ‘side effects’ to highlight 29 papers that would facilitate this discussion. Results and discussion: Intensity modulated radiotherapy (IMRT), tomotherapy and protons all provide CSI which can reduce dose to normal tissue, however photon methods cannot eliminate exit dose as well as protons can. Research for each technique requires longer term follow up in order to prove that survival rates remain high whilst reducing late effects. Findings/conclusion: Proton therapy is the superior method of CSI in term of late effects, but more research is needed to evidence this. Until proton therapy is available in the UK IMRT should be utilised. - Highlights: • Craniospinal irradiation is vital in the treatment of medulloblastoma. • Survivors often suffer long term side effects which reduce quality of life. • Tomotherapy, IMRT and proton therapy reduce late effects by sparing normal tissue. • Proton therapy offers superior dose distribution but further research is necessary. • IMRT should be employed for photon radiotherapy.

  9. Influence of ligation method on friction resistance of lingual brackets with different second-order angulations: an in vitro study

    Directory of Open Access Journals (Sweden)

    Graziane Olímpio Pereira

    Full Text Available ABSTRACT Objective: To evaluate stainless steel archwire static friction in active and passive self-ligating lingual and conventional brackets with second-order angulations. Methods: Two conventional lingual brackets for canines (STb light/Ormco; PSWb/Tecnident, and two self-ligating brackets, one active (In-Ovation L/GAC and the other passive (3D/ Forestadent, were evaluated. A stainless steel archwire was used at 0°, 3° and 5° angulations. Metal ligatures, conventional elastic ligatures, and low friction elastic ligatures were also tested. A universal testing machine applied friction between brackets and wires, simulating sliding mechanics, to produce 2-mm sliding at 3 mm/minute speed. Results: Two-way analysis of variance demonstrated a significant effect of the interaction between brackets and angulations (p < 0.001. Tukey test indicated that the highest frictional resistance values were observed at 5° angulation for In-Ovation L, PSWb bracket with non conventional ligature, and STb bracket with metal ligature. As for 3D, PSWb with conventional or metal ligatures, and STb brackets with non conventional ligature, showed significantly lower static frictional resistance with 0° angulation. At 0° angulation, STb brackets with metal ties, In-Ovation L brackets and 3D brackets had the lowest frictional resistance. Conclusions: As the angulation increased from 0° to 3°, static friction resistance increased. When angulation increased from 3° to 5°, static friction resistance increased or remained the same. Self-ligating 3D and In-Ovation L brackets, as well as conventional STb brackets, seem to be the best option when sliding mechanics is used to perform lingual orthodontic treatment.

  10. Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units

    Directory of Open Access Journals (Sweden)

    Javad Chalipa

    2017-01-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED light curing units on shear bond strength (SBS of metal and ceramic brackets to tooth surface.Materials and Methods: Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10. Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer’s instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI.Results: The mean SBS of samples in groups A (high-power LED, metal bracket, B (high-power LED, ceramic bracket, C (conventional LED, metal bracket and D (conventional LED, ceramic bracket was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional and bracket type on SBS was not statistically significant (P=0.483. In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (P<0.001. The ARI score was not significantly influenced by the interaction between the type of LED unit and bracket. Conclusions: The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets.Keywords: Orthodontic Brackets; Shear Strength; Light-Curing of Dental Adhesives

  11. Effect of Surface Treatment on Enamel Cracks After Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching Versus Acid-Etching.

    Science.gov (United States)

    Ghaffari, Hassanali; Mirhashemi, Amirhossein; Baherimoghadam, Tahereh; Azmi, Amir; Rasooli, Reza

    2017-09-01

    This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique. This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60μs, 80% water and 60% air). Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene's test was applied to assess the equality of variances. No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05). Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding.

  12. A hybrid electron and photon IMRT planning technique that lowers normal tissue integral patient dose using standard hardware.

    Science.gov (United States)

    Rosca, Florin

    2012-06-01

    To present a mixed electron and photon IMRT planning technique using electron beams with an energy range of 6-22 MeV and standard hardware that minimizes integral dose to patients for targets as deep as 7.5 cm. Ten brain cases, two lung, a thyroid, an abdominal, and a parotid case were planned using two planning techniques: a photon-only IMRT (IMRT) versus a mixed modality treatment (E+IMRT) that includes an enface electron beam and a photon IMRT portion that ensures a uniform target coverage. The electron beam is delivered using a regular cutout placed in an electron cone. The electron energy was chosen to provide a good trade-off between minimizing integral dose and generating a uniform, deliverable plan. The authors choose electron energies that cover the deepest part of PTV with the 65%-70% isodose line. The normal tissue integral dose, the dose for ring structures around the PTV, and the volumes of the 75%, 50%, and 25% isosurfaces were used to compare the dose distributions generated by the two planning techniques. The normal tissue integral dose was lowered by about 20% by the E+IMRT plans compared to the photon-only IMRT ones for most studied cases. With the exception of lungs, the dose reduction associated to the E+IMRT plans was more pronounced further away from the target. The average dose ratio delivered to the 0-2 cm and the 2-4 cm ring structures for brain patients for the two planning techniques were 89.6% and 70.8%, respectively. The enhanced dose sparing away from the target for the brain patients can also be observed in the ratio of the 75%, 50%, and 25% isodose line volumes for the two techniques, which decreases from 85.5% to 72.6% and further to 65.1%, respectively. For lungs, the lateral electron beams used in the E+IMRT plans were perpendicular to the mostly anterior/posterior photon beams, generating much more conformal plans. The authors proved that even using the existing electron delivery hardware, a mixed electron/photon planning

  13. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques; Developpement, amelioration et calibration des mesures de taux de reaction neutroniques: elaboration d`une base de techniques standards

    Energy Technology Data Exchange (ETDEWEB)

    Hudelot, J.P

    1998-06-19

    In order to improve and to validate the neutronic calculation schemes, perfecting integral measurements of neutronic parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronic reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO{sub 2}) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of {sup 238}U (defined as the ratio of {sup 238}U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for {sup 242}Pu (on MOX rods) and

  14. Effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cements.

    Science.gov (United States)

    Pereira, Tatiana Bahia Junqueira; Jansen, Wellington Corrêa; Pithon, Matheus Melo; Souki, Bernardo Quiroga; Tanaka, Orlando Motohiro; Oliveira, Dauro Douglas

    2013-08-01

    The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups.

  15. Comparison of deflection forces of esthetic archwires combined with ceramic brackets*

    Science.gov (United States)

    MATIAS, Murilo; de FREITAS, Marcos Roberto; de FREITAS, Karina Maria Salvatore; JANSON, Guilherme; HIGA, Rodrigo Hitoshi; FRANCISCONI, Manoela Fávaro

    2018-01-01

    Abstract Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Methods Non-coated NiTi (NC), rhodium coated NiTi (RC), teflon coated NiTi (TC), epoxy coated NiTi (EC), fiber-reinforced polymer (FRP), and the three different conventional brackets metal-insert polycrystalline ceramic (MI-PC), polycrystalline ceramic (PC) and monocrystalline ceramic (MC) were used. The specimens were set up on a clinical simulation device and evaluated in a Universal Testing Machine (Instron). An acrylic device, representative of the right maxillary central incisor was buccolingually activated and the unloading forces generated were recorded at 3, 2, 1 and 0.5 mm. The speed of the testing machine was 2 mm/min. ANOVA and Tukey tests were used to compare the different archwires and brackets. Results The brackets presented the following decreasing force ranking: monocrystalline, polycrystalline and polycrystalline metal-insert. The decreasing force ranking of the archwires was: rhodium coated NiTi (RC), non-coated NiTi (NC), teflon coated NiTi (TC), epoxy coated NiTi (EC) and fiber-reinforced polymer (FRP). At 3 mm of unloading the FRP archwire had a plastic deformation and produced an extremely low force in 2; 1 and 0.5 mm of unloading. Conclusion Combinations of the evaluated archwires and brackets will produce a force ranking proportional to the combination of their individual force rankings. PMID:29451650

  16. Evaluation of surface roughness of the bracket slot floor—a 3D perspective study

    Directory of Open Access Journals (Sweden)

    Chetankumar O. Agarwal

    2016-01-01

    Full Text Available Abstract Background An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. Methods All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM machine and to qualitatively analyse the average surface roughness (Sa of the bracket slot floor with the help of a three-dimensional (3D non-contact optical surface profilometer machine. Results The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0—very rough surface, group C = 1—rough surface, group B = 2—smooth surface, and group D = 3—very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Conclusions Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.

  17. Expert training with standardized operative technique helps establish a successful penile prosthetics program for urologic resident education.

    Science.gov (United States)

    King, Ashley B; Klausner, Adam P; Johnson, Corey M; Moore, Blake W; Wilson, Steven K; Grob, B Mayer

    2011-10-01

    The challenge of resident education in urologic surgery programs is to overcome disparity imparted by diverse patient populations, limited training times, and inequalities in the availability of expert surgical educators. Specifically, in the area of prosthetic urology, only a small proportion of programs have full-time faculty available to train residents in this discipline. To examine whether a new model using yearly training sessions from a recognized expert can establish a successful penile prosthetics program and result in better outcomes, higher case volumes, and willingness to perform more complex surgeries. A recognized expert conducted one to two operative training sessions yearly to teach standardized technique for penile prosthetics to residents. Each session consisted of three to four operative cases performed under the direct supervision of the expert. Retrospective data were collected from all penile prosthetic operations before (February, 2000 to June, 2004: N = 44) and after (July, 2004 to October, 2007: N = 79) implementation of these sessions. Outcomes reviewed included patient age, race, medical comorbidities, operative time, estimated blood loss, type of prosthesis, operative approach, drain usage, length of stay, and complications including revision/explantation rates. Statistical analysis was performed using Student's t-tests, Fisher's tests, and survival curves using the Kaplan-Meier technique (P value ≤ 0.05 to define statistical significance). Patient characteristics were not significantly different pre- vs. post-training. Operative time and estimated blood loss significantly decreased. Inflatable implants increased from 19/44 (43.2%, pre-training) to 69/79 (87.3%, post-training) (P prosthetics surgery. © 2011 International Society for Sexual Medicine.

  18. On hamiltonian systems with even and odd Poisson brackets and on the duality of their conservation laws

    International Nuclear Information System (INIS)

    Volkov, D.V.; Pashnev, A.I.; Soroka, V.A.; Tkach, V.I.

    1986-01-01

    Taking as example the Witten supersymmetric mechanics it is shown that the hamiltonian system with equal number of even and odd canonical variables admits simultaneously the introduction of even and odd Poisson brackets. When using bracket operations of different graduation the canonical variable equations are not varied whereas the motion integrals with opposite Grassman graduation become dual transforming into each other at the transition to Poisson bracket with opposite graduation

  19. Torque efficiency of square and rectangular archwires into 0.018 and 0.022 in. conventional brackets

    Directory of Open Access Journals (Sweden)

    Spyridon N. Papageorgiou

    2016-01-01

    Full Text Available Abstract Background The aim of this study was to compare the torque efficacy of square and rectangular wires in 0.018- and 0.022-in. conventionally ligated brackets. Methods Brackets of the same prescription were evaluated in both slot dimensions. Identical acrylic resin models of the maxilla were bonded with the brackets and mounted on the Orthodontic Measurement and Simulation System. Ten 0.018 × 0.018 in., 0.018 × 0.022 in., and 0.018 × 0.025 in. stainless steel wires were evaluated in the 0.018-in. brackets and ten 0.019 × 0.019 in., 0.019 × 0.025 in., and 0.019 × 0.026 in. stainless steel wires were evaluated in the 0.022-in. brackets. A 15° buccal root torque was gradually applied to the right central incisor bracket, and the moments were recorded at this position. One-way ANOVA was applied for both bracket slot sizes along with post hoc analysis for the various archwire sizes. Results The mean measured moments varied between 10.78 and 30.60 Nmm among the assessed wire-and-bracket combinations. Both square and rectangular archwires in the 0.018-in. bracket system exerted statistically significantly higher moments in comparison with their counterparts in the 0.022-in. bracket system. Rectangular archwires exerted statistically significantly higher moments than square archwires, both for the 0.018- and the 0.022-in. bracket system. Conclusions Rectangular archwires seem to be more efficient in torque exertion, especially in 0.018-in. brackets.

  20. Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash

    Directory of Open Access Journals (Sweden)

    Soodeh Tahmasbi

    2015-09-01

    Full Text Available Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various man-ufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022” Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye. These brackets along with stainless steel (SS or nickel-titanium (NiTi orthodontic wires (0.016", round were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP difference of each bracket-wire couple was measured with a Satu-rated Calomel Reference Electrode (Ag/AgCl saturated with KCl via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and speci-mens with corrosion were analyzed with scanning electron microscopy (SEM. Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0.05. Corrosion rate of brackets coupled with NiTi wires was higher than that of brack-ets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recom-mended when using them.

  1. In vitro evaluation of microleakage under ceramic and metal brackets bonded with LED and plasma arc curing.

    Science.gov (United States)

    Davari, Abdolrahim; Yassaei, Soghra; Karandish, Mariam; Zarghami, Fateme

    2012-09-01

    The aim of the present study was to evaluate these two high intensity light curing units regarding microleakage beneath metal and ceramic brackets. A total of 60 freshly extracted human premolar teeth were randomly divided into four groups of 15 samples; group I: Metal bracket + LED cured, group II: Ceramic bracket + LED cured, group III: Metal bracket + plasma arc cured, group IV: Ceramic bracket + plasma arc cured. After photopolymerization, the teeth were immersed in water and thermocycled (500 cycles between 5 and 55). Specimens were further sealed with nail varnish and stained with 5% basic fuchsin for 24 hours. All of the teeth were sectioned with two parallel longitudinal occlusogingival cuts and examined under a stereomicroscope. The microleakage was measured with a digital caliper and scored from 0 to 3 for marginal microleakage at the bracket-adhesive and adhesive-enamel interfaces from both the occlusal and gingival margins. Microleakage was detected in all groups. The plasma arc cured group showed less microleakage than light emitting diode (LED) cured in all samples at the enamel-adhesive interface at the gingival margin (ceramic brackets, p = 0.009 and metal brackets, p = 0.005). The plasma arc cured samples showed less microleakage than LED cured in metal brackets at the adhesive-brackets interface at the occlusal margin (p = 0.033). While curing with an LED unit, ceramic brackets displayed significantly less microleakage than metal ones at the gingival margin of adhesive-enamel interface (p = 0.013). The gingival margin in all groups exhibited higher microleakage compared with those observed in occlusal sides in all sample groups (p white spot lesions beneath the bracket base.

  2. Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units.

    Science.gov (United States)

    Chalipa, Javad; Jalali, Yasamin Farajzadeh; Gorjizadeh, Fatemeh; Baghaeian, Pedram; Hoseini, Mohammad Hashem; Mortezai, Omid

    2016-11-01

    The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface. Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer's instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI). The mean SBS of samples in groups A (high-power LED, metal bracket), B (high-power LED, ceramic bracket), C (conventional LED, metal bracket) and D (conventional LED, ceramic bracket) was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional) and bracket type on SBS was not statistically significant (P=0.483). In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (Punit and bracket. The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets.

  3. Assessment of the hardness of different orthodontic wires and brackets produced by metal injection molding and conventional methods

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    Shiva Alavi

    2017-01-01

    Conclusion: MIM orthodontic brackets exhibited hardness values much lower than those of SS orthodontic archwires and were more compatible with NiTi and beta-titanium archwires. A wide range of microhardness values has been reported for conventional orthodontic brackets and it should be considered that the manufacturing method might be only one of the factors affecting the mechanical properties of orthodontic brackets including hardness.

  4. Should hand-assisted retroperitoneoscopic nephrectomy replace the standard laparoscopic technique for living donor nephrectomy? A meta-analysis.

    Science.gov (United States)

    Elmaraezy, Ahmed; Abushouk, Abdelrahman Ibrahim; Kamel, Moaz; Negida, Ahmed; Naser, Omar

    2017-04-01

    We performed this meta-analysis to compare hand-assisted retroperitoneoscopic (HARP) and traditional laparoscopic (TLS) techniques for living donor nephrectomy. We searched PubMed, Cochrane Central, EMBASE, and Web of science for prospective studies, comparing HARP and TLS techniques. Data were extracted from eligible studies and pooled as risk ratios (RR) or standardized mean difference (SMD), using RevMan software (version 5.3 for windows). We performed a sensitivity analysis to test the robustness of our evidence and a subgroup analysis to stratify intraoperative complications on Clavien-Dindo score. Seven studies (498 patients) were included in the final analysis. HARP was superior to TLS in terms of shortening the operative duration (SMD = -0.84, 95% CI [-1.18 to -0.50]) and warm ischemia time (SMD = -0.93, 95% CI [-1.13 to -0.72]). There was no significant difference between HARP and TLS in terms of blood loss (SMD = 0.13, 95% CI [-0.50 to 0.76]), hospital stay (SMD = -0.27, 95% CI [-0.70 to 0.15]) or graft survival (RR = 0.97, 95% CI [0.92 to 1.02]). The overall risk ratio of intraoperative complications did not differ significantly between the two groups (RR = 0.62, 95% CI [0.31 to 1.21]). Our meta-analysis shows that HARP was associated with a shorter surgery duration and less warm ischemia time than TLS. However, no significant differences were found between the two groups in terms of graft survival or intraoperative complication rates. We recommend HARP over TLS for living donor nephrectomy; however, future studies with larger sample sizes are recommended to compare both techniques in terms of operative safety and quality of life outcomes. Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  5. Slot deformation of various stainless steel bracket due to the torque force of the beta-titanium wire

    Science.gov (United States)

    Huda, M. M.; Siregar, E.; Ismah, N.

    2017-08-01

    Stainless steel bracket slot deformation ffects the force applied to teeth and it can impede tooth movement and prolong orthodontic treatment time. The aim of this study is to determine the slot deformation due to torque of a 0.021 × 0.025 inch Beta Titanium wire with a torsional angle of 30° and 45° for five different bracket brands: y, 3M, Biom, Versadent, Ormco, and Shinye. The research also aims to compare the deformation and amount of torque among all five bracket brands at torsional angles of 30° and 45°. Fifty stainless steel edgewise brackets from the five bracket group brands (n=10) were attached to acrylic plates. The bracket slot measurements were carried out in two stages. In the first stage, the, deformation was measured by calculating the average bracket slot height using a stereoscopy microscope before and after application of torque. In the second stage, the torque was measured using a torque measurement apparatus. The statistical analysis shows that slot deformations were found on all five bracket brands with a clinical permanent deformation on the Biom (2.79 μm) and Shinye (2.29 μm) brackets. The most torque was observed on the 3M bracket, followed by the Ormco, Versadent, Shinye, and Biom brackets. When the brands were compared, a correlation between bracket slot deformation and the amount of torque was found, but the correlation was not statistically significant for the 3M and Ormco brackets and the Biom and Shinye brackets. There is a difference in the amount of torque between the five brands with a torsional angle of 30° (except the 3M and Ormco brackets) and those with a torsional angle of 45°. The composition of the metal and the manufacturing process are the factors that influence the occurrence of bracket slot deformation and the amount of torque. A manufacturing process using metal injection molding (MIM) and metal compositions of AISI 303 and 17-4 PH stainless steel reduce the risk of deformation.

  6. Standard Test Method for Oxygen Content Using a 14-MeV Neutron Activation and Direct-Counting Technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers the measurement of oxygen concentration in almost any matrix by using a 14-MeV neutron activation and direct-counting technique. Essentially, the same system may be used to determine oxygen concentrations ranging from over 50 % to about 10 g/g, or less, depending on the sample size and available 14-MeV neutron fluence rates. Note 1 - The range of analysis may be extended by using higher neutron fluence rates, larger samples, and higher counting efficiency detectors. 1.2 This test method may be used on either solid or liquid samples, provided that they can be made to conform in size, shape, and macroscopic density during irradiation and counting to a standard sample of known oxygen content. Several variants of this method have been described in the technical literature. A monograph is available which provides a comprehensive description of the principles of activation analysis using a neutron generator (1). 1.3 The values stated in either SI or inch-pound units are to be regarded...

  7. Technique for evaluation of spatial resolution and microcalcifications in digital and scanned images of a standard breast phantom

    International Nuclear Information System (INIS)

    Santana, Priscila do C.; Gomes, Danielle S.; Oliveira, Marcio A.; Oliveira, Paulo Marcio C. de; Meira-Belo, Luiz C.; Nogueira-Tavares, Maria S.

    2011-01-01

    In this work, an automated methodology to evaluate digital and scanned images of a standard phantom (Phantom Mama) was studied. The Phantom Mama was used as an important tool to check the quality of mammographs. The scanned images were digitized using a ScanMaker 9800XL, with resolution of 900 dpi. The aim of this work is to test an automatic methodology for evaluation of spatial resolution and microcalcifications group of phantom mama images acquired with the same parameters in the same equipment. In order to analyze the images we have used the ImageJ software (in Java) which is public domain. We have used the Fast Fourier transform technique to evaluate the spatial resolution and used the ImageJ function Subtract Background and the Light Background plus Sliding Paraboloid on the evaluation of the five groups of microcalcifications on the breast phantom to assess the viability of using automated methods for both types of images. The methodology was adequate for evaluated the microcalcifications group and the spatial resolution in scanned and digital images, but the Phantom Mama doesn't provide sufficient parameters to evaluate the spatial resolution in this images. (author)

  8. Orthodontic Metallic Lingual Brackets: The Dark Side of the Moon of Bond Failures?

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    Maria Francesca Sfondrini

    2017-07-01

    Full Text Available Lingual orthodontics, among both young and adult patients, increased in popularity during last years. The purposes of the present investigation were to evaluate the shear bond strength (SBS values and Adhesive Remnant Index (ARI scores of different lingual brackets compared with a vestibular control bracket. One hundred bovine teeth were extracted and embedded in resin blocks. Four different lingual brackets (Idea, Leone; STB, Ormco; TTR, RMO; 2D, Forestadent and a vestibular control bracket (Victory, 3M were bonded to the bovine enamel surfaces and subsequently shear tested to failure utilizing a Universal Testing Machine. SBS values were measured. A microscopic evaluation was performed to obtain ARI scores. Statistical analysis was performed at a statistically significant level of p < 0.05 to determine significant differences in SBS values and ARI Scores. No statistically significant variations in SBS were reported among the different groups. Conversely, significant differences were shown in ARI scores among the various groups. Clinical relevance of the present study is that orthodontists can expect similar resistance to debonding forces from lingual appliances as with vestibular brackets.

  9. Influence of flowable resins on the shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Park, Soo-Byung; Son, Woo-Sung; Ko, Ching-Chang; García-Godoy, Franklin; Park, Mi-Gyoung; Kim, Hyung-Il; Kwon, Yong Hoon

    2009-11-01

    The present study tested the shear bond strength (SBS) of orthodontic brackets bonded to teeth using flowable resins. A total of 105 human teeth were divided into seven groups. The brackets in each group were bonded to the tooth substrates using a Transbond XT adhesive and six other different flowable resins, respectively. Each adhesive resin was light-cured using a quartz-tungsten-halogen (QTH) light for 40 seconds. The brackets were debonded in shear mode using a universal testing machine. The brackets bonded using Tetric Flow and Grandio Flow showed slightly greater SBS values (13.0+/-1.8 and 12.2+/-1.2 MPa, respectively) than the Transbond XT adhesive (12.1+/-1.2 MPa). However, the SBS values of Transbond XT, X-flow, Tetric Flow, Grandio Flow, and Filtek Z350 flow were not significantly different. As for Admira Flow and Aelite Flow, they scored significantly lower SBS values (7.0+/-2.1 and 9.2+/-1.3 MPa, respectively) than the other groups. On bracket failure mode, statistical analysis revealed a similar failure mode among all the seven test groups.

  10. Evaluation of a new nano-filled restorative material for bonding orthodontic brackets.

    Science.gov (United States)

    Bishara, Samir E; Ajlouni, Raed; Soliman, Manal M; Oonsombat, Charuphan; Laffoon, John F; Warren, John

    2007-01-01

    To compare the shear bond strength of a nano-hybrid restorative material, Grandio (Voco, Cuxhaven, Germany), to that of a traditional adhesive material (Transbond XT; 3M Unitek, Monrovia, CA, USA) when bonding orthodontic brackets. Forty teeth were randomly divided into 2 groups: 20 teeth were bonded with the Transbond adhesive system and the other 20 teeth with the Grandio restorative system, following manufacturer's instructions. Student t test was used to compare the shear bond strength of the 2 systems. Significance was predetermined at P 5 .05. The t test comparisons (t = 0.55) of the shear bond strength between the 2 adhesives indicated the absence of a significant (P = .585) difference. The mean shear bond strength for Grandio was 4.1 +/- 2.6 MPa and that for Transbond XT was 4.6 +/- 3.2 MPa. During debonding, 3 of 20 brackets (15%) bonded with Grandio failed without registering any force on the Zwick recording. None of the brackets bonded with Transbond XT had a similar failure mode. The newly introduced nano-filled composite materials can potentially be used to bond orthodontic brackets to teeth if its consistency can be more flowable to readily adhere to the bracket base.

  11. Influence of lingual bracket position on microbial and periodontal parameters in vivo

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    Maria Francesca Sfondrini

    2012-06-01

    Full Text Available OBJECTIVE: Lingual orthodontics is becoming more popular in dental practice. The purpose of the present investigation was to compare plaque formation on teeth bonded with the same bracket onto buccal or lingual surface, with non-bonded control teeth, via an in vivo growth experiment over a 30-day period. MATERIAL AND METHODS: A randomized controlled trial with split-mouth design was set up enrolling 20 dental students. Within each subject sites with buccal and lingual brackets and control sites were followed. Clinical periodontal parameters (periodontal pocket depth: PPD; bleeding on probing: BOP were recorded at baseline and on days 1, 7 and 30. Microbiological samples were taken from the brackets and the teeth on days 1, 7 and 30 to detect colony-forming units (CFU. Total CFU, streptococci CFU and anaerobe CFU were measured. RESULTS: No significant differences (P>0.05 were found between buccal and lingual brackets in terms of clinical periodontal parameters and microbiological values. Conclusion: Bracket position does not have significant impact on bacterial load and on periodontal parameters.

  12. Influence of surface treatments on the shear bond strength of orthodontic brackets to porcelain

    Science.gov (United States)

    Wang, Cong; Zeng, Jishan; Wang, Shaoan; Yang, Zheng; Huang, Qian; Chen, Pixiu; Zhou, Shujuan; Liu, Xiaoqing

    2008-11-01

    The purpose of this study was to investigate the effect of various surface treatments after different storage time and thermocycling on the shear bond strength of orthodontic brackets to the feldspathic porcelain surfaces. 128 disc-shaped porcelain specimens were randomly assigned to the following surface treatments: 9.6% HFA, 9.6% HFA combined with silane, 50 μ aluminum trioxide sandblasting followed by silane and application of silane after 37% phosphoric acid. Metal or ceramic brackets were bonded onto each treated porcelain facet with light cured resin. The samples were stored in 37 °C water 1 day or 7 days, thermocycled 500 times from 5 to 55 °C. The shear bond strengths were measured (1 mm/min), and statistically analyzed. The bond failure sites were classified according to ARI system. The surface of the glazed, sandblasted, hydrofluoric and phosphoric acid etched porcelain were examined with SEM. All groups achieved reasonable bond strengths to withstand the application of orthodontic forces. Water storage for 7 days caused lower shear bond strength than that of 1 day. But there is no statistically significant difference between the two groups. The mean shear bond strength provided by ceramic bracket with mechanical retention had no statistical difference with that of metal bracket. Therefore, the optimal treatment for orthodontic brackets bonding to feldspathic porcelain was to apply phosphoric acid combined with silane.

  13. Assessment of the dimensions and surface characteristics of orthodontic wires and bracket slots

    Directory of Open Access Journals (Sweden)

    Gabriel Schmidt Dolci

    2013-04-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the dimensions and surface characteristics of orthodontic wires and bracket slots of different commercial brands. METHODS: Thirty metallic brackets (0.022 x 0.028-in and 0.022 x 0.030-in were divided in three groups: DYN/3M group = Dyna-Lock, 3M/Unitek (stainless steel, or SS; STD/MO group = Slim Morelli (SS; and Ni-Free/MO group = Slim Morelli (Ni-Free. The stainless steel wires (0.019 x 0.025in were divided into two groups: MO group = Morelli; and 3M group = 3M/Unitek. The bracket and wire measurements were done by two methods: (a Surface Electron Microscopy (SEM, and (b Profile projection. The surface analysis was done qualitatively, based on SEM images and/or by a rugosimeter. The quantitative results were analyzed by ANOVA with Tukey's test (p < 0.05 and Student's t test. RESULTS: A significant difference in the dimensions of slots was observed, and the NiFree/MO group showed the greatest changes when compared to the other groups. The analysis of surface topography of the brackets indicated greater homogeneity of the metallic matrix for DYN/3M and STD/MO groups. As for the dimensions of the wires, groups showed statistically different mean heights. CONCLUSIONS: It was concluded that wires and brackets slots can present altered dimensions, which might directly and unintentionally affect the planned tooth movement.

  14. Effect of Adhesive Type on the Shear Bond Strength of Metal Brackets to Two Ceramic Substrates

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Ahmad Akhoundi

    2014-04-01

    Full Text Available Increased number of adult patients requesting orthodontic treatment result in bonding bracket to ceramic restorations more than before. The aim of this study was to evaluate and compare the shear bond strength of orthodontic brackets bonded to two types of ceramic bases with conventional orthodontic bonding resin and a new nano-filled composite resin.Twenty four feldespathic porcelain and 24 lithium disilicate ceramic disks were fabricated. All of the samples were conditioned by sandblasting, hydrofluoric acid and silane. Maxillary incisor metal brackets were bonded to half of the disks in each group by conventional orthodontic bonding resin and the other half bonded with a nano-filled composite. The samples then were thermocycled for 2000 cycle between 5-55° C. Shear bond strength was measured and the mode of failure was examined. Randomly selected samples were also evaluated by SEM.The lowest bond strength value was found infeldespathic ceramic bonded by nano-filled composite (p<0.05. There was not any statistically significant difference between other groups regarding bond strength. The mode of failure in the all groups except group 1 was cohesive and porcelain damages were detected.Since less damages to feldspathic porcelain was observed when the nano-filled composite was used to bond brackets, the use of nano-filled composite resins can be suggested for bonding brackets to feldspathic porcelain restorations.

  15. Perkiraan Fatigue Life pada Bracket Kapal Tanker Berdasarkan Common Structural Rules

    Directory of Open Access Journals (Sweden)

    Dita septiana

    2012-09-01

    Full Text Available Umur kelelahan (fatigue life dari struktur kapal dianalisis dengan menggunakan standar pada Common Structural Rules for Double Hull Oil Tanker. Kapal tanker single hull direncanakan akan dikonversi menjadi FPSO sehingga perlu diketahui sisa fatigue life konstruksinya. Dalam penelitian ini, fokus analisis dilakukan pada konstruksi bracket karena bracket sebagai salah satu penopang yang esensial pada kapal ini. Oleh karena itu, perlu diketahui letak bracket dengan tegangan paling besar dan besar fatigue lifenya. Kapal tersebut dimodelkan menggunakan softwareMSC Pastran sebagai pre-processor dan MSC Nastran sebagai processor. Bagian kapal yang dimodelkan adalah 3 ruang muat pada midship. Ruang muat pada bagian tengah dari ketiga ruang muat tersebut adalah ruang muat yang paling besar. Fatigue life yang dianalisa merupakan pengaruh dari beban lingkungan (beban gelombang air laut dan beban internal (beban tangki. Kondisi pembebanan yang dilakukan ada 6 macam load cases sesuai dengan ketentuan CSR. Tegangan pada bracket yang didapat dari pemodelan diambil tegangan yang paling besar untuk dianalisa fatigue lifenya. Hasil perhitungan menunjukkan bahwa bracket dengan tegangan paling besar terjadi pada web frame 7 pada ruang muat tengah dan pada kondisi pembebanan A2 didapat umur kapal yang paling rendah yaitu sebesar 26 tahun.

  16. Shear bond strength of metallic and ceramic brackets using color change adhesives

    Directory of Open Access Journals (Sweden)

    Aisha de Souza Gomes Stumpf

    2013-04-01

    Full Text Available OBJECTIVE: To determine the shear bond strength of orthodontic brackets using color change adhesives that are supposed to aid in removing excess of bonding material and compare them to a traditional adhesive. METHODS: Ninety metallic and ninety ceramic brackets were bonded to bovine incisors using two color change adhesives and a regular one. A tensile stress was applied by a universal testing machine. The teeth were observed in a microscope after debonding in order to determine the Adhesive Remnant Index (ARI. RESULTS: The statistical analysis (ANOVA, Tukey, and Kruskall-Wallis tests demonstrated that the mean bond strength presented no difference when metallic and ceramic brackets were compared but the bond resistance values were significantly different for the three adhesives used. The most common ARI outcome was the entire adhesive remaining on the enamel. CONCLUSIONS: The bond strength was similar for metallic and ceramic brackets when the same adhesive system was used. ARI scores demonstrated that bonding with these adhesives is safe even when ceramic brackets were used. On the other hand, bond strength was too low for orthodontic purposes when Ortho Lite Cure was used.

  17. A Comparison of Gender and Socioeconomic Bracket in Fourth Grade Students when Measuring Volume

    Science.gov (United States)

    Jennings, Kelly A.

    The goal of this study was to assess students' abilities when measuring volume as well as providing a hands-on method for designing a water-filtration process. I studied the trends among gender, time, and ability to measure water in two different groups of fourth grade students. Fourth grade students from both higher income and lower income school districts visited a STEM (Science, Technology, Engineering, and Mathematics) Studio in order to participate in hands-on, problem-based learning. The students in this study attempted to solve the "Dirty Water Problem" by measuring 281ml of dirty water solution, and using household tools to filter and clean the dirty water. This study showed that 68% of students from a high-income socioeconomic bracket were able to measure a determined volume of water independently. Meanwhile, only 18% of students from a low-income socioeconomic bracket were able to complete the same task independently. In the low-income bracket, 78% of students required assistance measuring a volume of water, indicating that the majority of these students performed below grade level. Where time spent at the station was concerned, the difference between high-income and low-income socioeconomic brackets was insignificant. Key Words: STEM, measurement, volume, design, Dirty Water Problem, socioeconomic bracket.

  18. Pulpal Thermal Changes following Er-YAG Laser Debonding of Ceramic Brackets

    Directory of Open Access Journals (Sweden)

    Didem Nalbantgil

    2014-01-01

    Full Text Available Lasers are effective in debonding ceramic brackets. Unfortunately, while reducing the adhesive bond strength, lasers are also reported to increase pulpal temperature. The aim of this study was to evaluate the shear bond strengths and temperature increase levels after debonding ceramic brackets using an Er-YAG laser with or without water-cooling. Sixty polycrystalline upper premolar ceramic brackets were placed on the labial surface of sixty human premolar teeth which were randomly divided into three groups of twenty. A laser pulse at 5 W for 9 seconds was delivered to each bracket in both study groups either with water-cooling (water group or without water-cooling (waterless group using an Er-YAG laser. Debonding was performed 45 seconds after laser exposure and shear bond strengths were measured. Data comparison revealed a statistically significant difference between the groups. Mean temperature increases of 2.41°C and 4.59°C were recorded for the water and waterless laser groups, respectively. The shear bond strength value for the control group was 22.76 MPa and 10.46 and 6.36 MPa for the water and waterless laser groups, respectively. The application of Er-YAG laser with water-cooling was an efficient and safe method of debonding ceramic brackets.

  19. Bond strength evaluation of ceramic and stainless steel bracket bases subjected to cyclic tensile loading.

    Science.gov (United States)

    Soderquist, Scott A; Drummond, James L; Evans, Carla A

    2006-02-01

    The aim of this study was to evaluate the effects of loading, static and cyclic, on 1 stainless steel and 3 ceramic bracket bonding bases. The brackets were chosen because of the different characteristics of their bonding bases. The brackets in each group were bonded to bovine teeth by using the same adhesive and subjected to both static and cyclic tensile loading; the results were analyzed (ANOVA and Scheffé) for statistical differences among the groups. The analysis showed that ceramic brackets have unique characteristics compared with stainless steel; the most significant is higher bond strengths. The effects of cyclic loading were shown to be significant, in that fatigue testing caused a decrease in mean tensile bond strength for most groups. An additional factor on the bond strength might be the composition and design of the bracket base. Simulations of occlusal forces (a combination of tensile, shear, and compressive forces) to orthodontic materials during in-vitro studies in accordance with clinical use might adequately describe actual clinical performance.

  20. Shear bond strength of orthodontic brackets bonded to provisional crown materials utilizing two different adhesives.

    Science.gov (United States)

    Rambhia, Sameer; Heshmati, Reza; Dhuru, Virendra; Iacopino, Anthony

    2009-07-01

    To test the hypothesis that there is no difference in the shear bond strength of brackets bonded to provisional crown materials (PCMs) using two adhesive agents. Four PCMs were tested: Integrity, Jet, Protemp, and Snap. Forty cylindrical specimens of 10 mm diameter x 5 mm were prepared for each PCM. Ten specimens from each group were bonded to one of the two brackets, Clarity or Victory, using one of the two adhesives, Fuji Ortho LC or Ortho Bracket Adhesive. The brackets were debonded in shear at a cross-head speed of 5 mm/min, and the shear bond strength (SBS) was calculated. The type of failure was visually determined. The numeric data were analyzed using three-way analysis of variance and Tukey multiple range test at alpha = .05. The mean SBSs ranged from 2.81 MPa to 9.65 MPa. There was a significant difference between Snap and the other three materials (P .05). The bond failure for all the specimens was of the adhesive type between the PCM and the adhesive resin. The PCM Snap yielded a significantly lower mean SBS value compared to the other three materials. No significant differences were found between the brackets or the adhesives. The bond failure was of the adhesive type.

  1. Comparison of shear bond strength of four types of orthodontic brackets with different base technologies

    Directory of Open Access Journals (Sweden)

    Gaurang H Chaudhary

    2017-01-01

    Full Text Available Objectives: The aim of this study was to compare the shear bond strength (SBS of brackets systems with four different base technologies. Materials and Methods: Maxillary first premolars were randomly divided into four groups of thirty specimens each: (1 Master Series™ conventional twin, (2 T3™ self-ligating, (3 Victory series™ conventional twin, and (4 H4™ self-ligating brackets. Maxillary first premolars were bracketed using an acid-etch composite system, and the SBS measured using an Instron Universal Testing Machine at a crosshead speed of 2 mm/min. The ANOVA and Tukey's multiple comparison tests were performed with significance predetermined at P ≤ 0.05. Results: The overall mean bond strengths were 8.49 ± 2.93, 10.85 ± 3.34, 9.42 ± 2.97, and 9.73 ± 2.62 for the Groups 1, 2, 3, and 4 brackets, respectively. One-way ANOVA test gave an F = 3.182 with a P = 0.026. The Group 1 and Group 2 were observed to have statistically significant difference with a P = 0.014. Conclusions: The T3 self-ligating one-piece design with microetched Quadra Grip™ base brackets had the highest bond strength. The SBS difference between Group 2, Group 3, and Group 4 was not significant, but the difference between Group 2 and Group 1 was statistically significant.

  2. Halogen light versus LED for bracket bonding: shear bond strength

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    Paulo Eduardo Guedes Carvalho

    2013-02-01

    Full Text Available INTRODUCTION: LED light-curing devices seek to provide a cold light activator which allows protocols of material polymerization with shorter duration. OBJECTIVE: The present study aimed to evaluate the shear bond strength of bracket bonding using three types of light-curing devices: One with halogen light (Optilight Plus - Gnatus and two with LEDs (Optilight CL - Gnatus and Elipar Freelight - 3M/ESPE. RESULTS: Comparing the results by analysis of variance, the Gnatus LED device showed an inferior statistical behavior in relation to other light sources, when activated by a short time. But, when it was used for 40 seconds, the polymerization results were consistent with the other evaluated sources. The device with the best average performance was the halogen light, followed by the 3M/ESPE LED. CONCLUSION: It was concluded that the LEDs may be indicated in orthodontic practice, as long as a protocol is used for the application of light with the activation time of 40 seconds.INTRODUÇÃO: os aparelhos de fotopolimerização por LED buscam proporcionar uma luz ativadora fria, que possibilite protocolos de polimerização do material com menor tempo de duração. OBJETIVO: avaliar a resistência à tração da colagem de braquetes, utilizando três tipos de aparelhos fotoativadores: um de luz halógena (Optilight Plus - Gnatus e outros dois de LED (Optilight CL - Gnatus; e Elipar Freelight - 3M/Espe. RESULTADOS: comparando os resultados por meio da análise de variância, o aparelho de LED Gnatus apresentou comportamento estatístico inferior em relação às outras fontes de luz, quando ativado por tempo reduzido. Já quando foi utilizado o tempo de 40 segundos, os resultados de polimerização foram compatíveis com as demais fontes avaliadas. O aparelho que apresentou melhor desempenho médio foi o de luz halógena, seguido pelo LED 3M/Espe. CONCLUSÃO: concluiu-se que os LEDs podem ser indicados na prática ortodôntica, uma vez que seja utilizado

  3. Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires

    Directory of Open Access Journals (Sweden)

    Vanessa Vieira Leite

    2014-06-01

    Full Text Available OBJECTIVE: To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. MATERIAL AND METHODS : Abzil Kirium Capelozza (Pattern I and Easy Clip (Roth prescription incisor brackets were used. An elastomeric ligature or a ligating wire 0.10-in was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM. RESULTS: Steel-tied brackets (16.48 ± 8.31 showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 and self-ligating brackets (1.66 ± 1.57 (P 0.05. No statistical differences (P > 0.05 were found between zero (7.76 ± 8.46 and five-degree (7.19 ± 7.93 angulations. CONCLUSIONS: Friction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied

  4. Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash.

    Science.gov (United States)

    Tahmasbi, Soodeh; Ghorbani, Mohammad; Masudrad, Mahdis

    2015-01-01

    Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022" Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0.016", round) were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them.

  5. The influence of size and structure of metal orthodontic bracket base on bond strength on tooth enamel

    Directory of Open Access Journals (Sweden)

    Mitić Vladimir

    2009-01-01

    Full Text Available Introduction. The factors which may influence the bond strength of the applied orthodontic brackets on the tooth surface are the size and structure of the bracket base. Objective. The aim of the paper was to investigate the influence of size and shape of different types of brackets on bond strength on the enamel and analyze the remaining quality of adhesive material on the tooth surface after debonding of orthodontic brackets (adhesive remnant index - ARI. Methods. In this study, three types of metal brackets of different sizes and shapes of Dentaurum manufacturer were used (Utratrimm, Equilibrium 2, Discovery, Dentaurum, Inspringen, Germany. The brackets were applied onto the middle part of the anatomic crowns of buccal surfaces of 30 premolars extracted for orthodontic reasons. In addition, the pre-treatment of teeth by 37% orthophosphoric acid and adhesive material System1+ (Dentaurum, Germany were used. Results. The mean value of the bonded brackets bond strength of Discovery type after debonding was 8.67±0.32 MPa, while the value of the bonded brackets bond strength of Equilibrium 2 type amounted to 8.62±0.22 MPa. The value of the bonded brackets bond strength of Ultratrimm type after debonding was 8.22±0.49 MPa. There were no statistical differences in the values of bond strength regarding all three groups of the investigated orthodontic brackets (F=4.56; p<0.05. Conclusion. The base size and design of metal orthodontic brackets did not play a significant role in bond strength, while the values of ARI index were identical in all three investigated groups.

  6. Estudio de brackets autoligables mediante microscopía electrónica de barrido.

    OpenAIRE

    González Ruiz, Aiala

    2015-01-01

    Desde finales del siglo XIX, cuando Angle desarrolló el arco E en su afán de mover los dientes en los tres planos del espacio, se han ido creando diferentes tipos de brackets. Así, a día de hoy tenemos lo que conocemos como brackets preajustados, que llevan la información de 1º, 2º y 3er orden en su estructura interna para evitar las dobleces de los arcos. Sin embargo, el afán de los últimos años ha sido el reducir al mínimo la fricción creada entre bracket y ligadura, y por ello han surgido ...

  7. Evaluation of the friction force generated by monocristalyne and policristalyne ceramic brackets in sliding mechanics

    Directory of Open Access Journals (Sweden)

    Roberta Ferreira Pimentel

    2013-02-01

    Full Text Available OBJECTIVE: To evaluate and compare "in vitro" the maximum friction force generated by three types of esthetic brackets, two types of polycrystalline conventional ceramic brackets (20/40 and InVu and one type of sapphire monocrystalline bracket (Radiance in dry and artificial saliva wet settings. Also, to evaluate the influence exerted by artificial saliva on the friction forces of those brackets. METHODS: Tests were performed in dry and artificial saliva wet setting (Oral Balance by using an EMIC DL 10000 testing machine, simulating a 2 mm slide of 0.019 x 0.025-in rectangular stainless steel wires over the pre-angulated and pre-torqued (right superior canine, Roth prescription, slot 0.022 x 0.030-in brackets (n = 18 for each bracket. In order to compare groups in dry and wet settings, the ANOVA was used. For comparisons related to the dry versus wet setting, the student t test was used for each group. RESULTS: The results showed that in the absence of saliva the Radiance monocrystalline brackets showed the highest friction coefficients, followed by the 20/40 and the InVu polycrystalline brackets. In tests with artificial saliva, the Radiance and the 20/40 brackets had statistically similar friction coefficients and both were greater than that presented by the InVu brackets. The artificial saliva did not change the maximum friction force of the Radiance brackets, but, for the others (20/40 and InVu, an increase of friction was observed in its presence. CONCLUSION: The InVu brackets showed, in the absence and in the presence of saliva, the lowest friction coefficient.OBJETIVO: avaliar e comparar in vitro as cargas máximas de atrito geradas por três tipos de braquetes estéticos, sendo dois deles cerâmicos policristalinos convencionais (20/40 e InVu e um monocristalino de safira (Radiance, em ambientes seco e umedecido por saliva artificial. Também avaliar a influência exercida pela saliva artificial sobre as cargas de atrito dos referidos

  8. Comparison of measured and calculated contralateral breast doses in whole breast radiotherapy for VMAT and standard tangent techniques

    International Nuclear Information System (INIS)

    Tse, T.L.J; Bromley, R.; Booth, J.; Gray, A.

    2011-01-01

    Full text: Objective This study aims to evaluate the accuracy of calculated dose with the Eclipse analytical anisotropic algorithm (AAA) for contralateral breast (CB) in left-sided breast radiotherapy for dual-arc VMA T and standard wedged tangent (SWT) techniques. Methods and materials Internal and surface CB doses were measured with EBT2 film in an anthropomorphic phantom mounted with C-cup and D-cup breasts. The measured point dose was approximated by averaging doses over the 4 x 4 mm 2 central region of each 2 x 2 cm2 piece of film. The dose in the target region of the breast was also measured. The measured results were compared to AAA calculations with calculation grids of I, 2.5 and 5 mm. Results In SWT plans, the average ratios of calculation to measurement for internal doses were 0.63 ± 0.081 and 0.5 I ± 0.28 in the medial and lateral aspects, respectively. Corresponding ratios for surface doses were 0.88 ± 0.22 and 0.38 ± 0.38. In VMAT plans, however, the calculation accuracies showed little dependence on the measurement locations, the ratios were 0.78 ± O. I I and 0.81 ± 0.085 for internal and surface doses. In general, finer calculation resolutions did not inevitably improve the dose estimates of internal doses. For surface doses, using smaller grid size I mm could improve the calculation accuracies on the medial but not the lateral aspects of CB. Conclusion In all plans, AAA had a tendency to underestimate both internal and surface CB doses. Overall, it produces more accurate results in VMAT than SWT plans.

  9. ANALISA KEKUATAN KONSTRUKSI BRACKET TOWING HOOK PADA TB. BONTANG DENGAN METODE ELEMEN HINGGA DAN RULES BKI

    Directory of Open Access Journals (Sweden)

    Imam Pujo Mulyatno

    2013-01-01

    Full Text Available Bracket towing hook construction planning is to make a construction that has the stress level of the allowable limit and can be accepted by the construction. Requirements for towing hook are structural strength if the stress levels that occur below the elastic region. By calculating the value of the maximum load, maximum stress, von mises stress and deflection (displasment that occur in the construction of bracket towing hook, so that known security level of construction that has been designed. Research on construction of the strength bracket towing hook need to be considered and carried out, where the stress caused by load about them should not exceed the maximum limit σyield materials and σallow based on the rules from the class. The reference to rules used in this research is based on the rules of Bureau Classification Indonesia. Analysis of the strength bracket towing hook construction is done by using finite element methode. The analysis used is a static load analysis to determine the characteristics and location of greatest stress on the construction bracket towing hook based on three variations of loading. Analysis results obtained using finite element methode based program of greatest stress maximum occurs in the condition of the bracket towing hook  with maximum horse power load that is equal to 44,2 N/mm2 where the most critical area occurs at node 457 which is located at frame number 23 lengthwise section and stiffener number 7 cross section. This stress is still in a safe condition because after compared with material σyield of 400 N/mm2 and σallow based BKI rules of 178,12 N/mm2 produce safety factor value of 9,05 and 4,03

  10. Comparison of shear bond strength of stainless steel brackets bonded with three light- cured adhesives

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    Zahra Minaei Basharik

    2015-09-01

    Full Text Available Introduction: The bonding process of the brackets to enamel has been a critical issue in orthodontic research. The purpose of this study was to evaluate the shear bond strength of 3 light-cured adhesives (transbond XT, Z250, light bond. Materials &Methods: In this study sixty extracted human premolars were collected and randomly divided into 3 test groups. All teeth were etched by 37% phosphoric acid. In first group brackets were bonded by Transbond XT adhesive, in group two brackets were bonded by Light bond adhesive and in third group were bonded by filtek Z250 composite. All of them were cured with Ortholux xt for 40 seconds.24 hours after thermocycling, Shear Bond Strength (SBS values of these brackets were recorded using a Universal Testing Machine. Adhesive Remnant Index (ARI scores were determined after the failure of the brackets, using Stereo Microscope the data were analyzed using ANOVA and Chi-square tests. Results: Mean shear bond strength of Transbond XT, light bond and Z250 were 28.9±2.25 MPa, 25.06±1.98 MPa and 26.8±2.57 MPa, respectively. No significant difference was observed in the SBS among the groups and a clinically acceptable SBS was found for the three adhesives. ARI scores were not significantly different between the various groups (P>0.05. Conclusion: This study showed that the Z250 can be used as light bond and transbond xt to bond orthodontic brackets and ARI and SBS scores were not significantly different.

  11. Assessment of dimensional accuracy of preadjusted metal injection molding orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Shiva Alavi

    2016-01-01

    Full Text Available Background: the aim of this study is to evaluate the dimensional accuracy of McLaughlin, Bennett, and Trevisi (MBT brackets manufactured by two different companies (American Orthodontics and Ortho Organizers and determine variations in incorporation of values in relation to tip and torque in these products. Materials and Methods: In the present analytical/descriptive study, 64 maxillary right central brackets manufactured by two companies (American Orthodontics and Ortho Organizers were selected randomly and evaluated for the accuracy of the values in relation to torque and angulation presented by the manufacturers. They were placed in a video measuring machine using special revolvers under them and were positioned in a manner so that the light beams would be directed on the floor of the slot without the slot walls being seen. Then, the software program of the same machine was used to determine the values of each bracket type. The means of measurements were determined for each sample and were analyzed with independent t-test and one-sample t-test. Results: Based on the confidence interval, it can be concluded that at 95% probability, the means of tip angles of maxillary right central brackets of these two brands were 4.1-4.3° and the torque angles were 16.39-16.72°. The tips in these samples were at a range of 3.33-4.98°, and the torque was at a range of 15.22-18.48°. Conclusion: In the present study, there were no significant differences in the angulation incorporated into the brackets from the two companies; however, they were significantly different from the tiP values for the MBT prescription. In relation to torque, there was a significant difference between the American Orthodontic brackets exhibited significant differences with the reported 17°, too.

  12. Metallurgical characterization, galvanic corrosion, and ionic release of orthodontic brackets coupled with Ni-Ti archwires.

    Science.gov (United States)

    Darabara, Myrsini S; Bourithis, Lefteris I; Zinelis, Spiros; Papadimitriou, George D

    2007-04-01

    In orthodontics, a combination of metallic alloys is placed into the oral cavity during medical treatment and thus the corrosion resistance and ionic release of these appliances is of vital importance. The aim of this study is to investigate the elemental composition, microstructure, hardness, corrosion properties, and ionic release of commercially available orthodontic brackets and Copper Ni-Ti archwires. Following the assessment of the elemental composition of the orthodontic wire (Copper Ni-Ti) and the six different brackets (Micro Loc, Equilibrium, OptiMESH(XRT), Gemini, Orthos2, and Rematitan), cyclic polarization curves were obtained for each material to estimate the susceptibility of each alloy to pitting corrosion in 1M lactic acid. Galvanic corrosion between the orthodontic wire and each bracket took place in 1M lactic acid for 28 days at 37 degrees C and then the ionic concentration of Nickel and Chromium was studied. The orthodontic wire is made up from a Ni-Ti alloy with copper additions, while the orthodontic brackets are manufactured by different stainless steel grades or titanium alloys. All tested wires and brackets with the exception of Gemini are not susceptible to pitting corrosion. In galvanic corrosion, following exposure for 28 days, the lowest potential difference (approximately 250 mV) appears for the orthodontic wire Copper Ni-Ti and the bracket made up from pure titanium (Rematitan) or from the stainless steel AISI 316 grade (Micro Loc). Following completion of the galvanic corrosion experiments, measurable quantities of chromium and nickel ions were found in the residual lactic acid solution. (c) 2006 Wiley Periodicals, Inc.

  13. Comparison of ankle-brachial index measured by an automated oscillometric apparatus with that by standard Doppler technique in vascular patients

    DEFF Research Database (Denmark)

    Korno, M.; Eldrup, N.; Sillesen, H.

    2009-01-01

    was calculated twice using both the methods on both legs. MATERIALS AND METHODS: We tested the automated oscillometric blood pressure device, CASMED 740, for measuring ankle and arm blood pressure and compared it with the current gold standard, the hand-held Doppler technique, by the Bland-Altman analysis....... RESULTS: Using the Doppler-derived ABI as the gold standard, the sensitivity and specificity of the oscillometric method for determining an ABI Udgivelsesdato: 2009/11...

  14. Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

    Directory of Open Access Journals (Sweden)

    Dziubińska A.

    2016-06-01

    Full Text Available The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

  15. Evaluation of soft tissue changes around the lips after bracket debonding using three-dimensional stereophotogrammetry.

    Science.gov (United States)

    Kim, Young-Kyun; Lee, Nam-Ki; Moon, Sang-Woon; Jang, Moon-Jung; Kim, Hyun-Suk; Yun, Pil-Young

    2015-09-01

    To evaluate the changes in soft tissue around the lips after orthodontic bracket debonding using three-dimensional (3-D) stereophotogrammetry. 3-D facial images of 20 subjects (10 men and 10 women; mean age, 26.81 ± 7.23 years) were taken with a white light scanner before and after debonding the labial brackets. Two images acquired from each subject were superimposed, and 15 soft tissue landmarks around the lips were plotted and analyzed. Statistical analysis was performed using both paired and independent t-tests (P orthodontic patients.

  16. Bracket/wire play: what to expect from tipping prescription on pre-adjusted appliances Folga braquete/fio: o que esperar da prescrição para inclinação nos aparelhos pré-ajustados

    Directory of Open Access Journals (Sweden)

    Leopoldino Capelozza Filho

    2012-08-01

    Full Text Available INTRODUCTION: The opinion on the 'straight-wire' concept has been evolving since its origin, characterized by faithful followers or absolute skepticism. Currently, it seems reasonable to state that most professionals have a more realistic and critical viewpoint, with an attitude that reveals Orthodontics' maturity and greater knowledge on the technique. The most relevant criticisms refer to the impossibility of the both the Straight-Wire and the Standard systems to completely express the characteristics related to the brackets due to mechanical deficiencies, such as bracket/wire play. OBJECTIVES: A critical analysis of this relationship, which is unclear due to lack of studies, was the scope of this paper. METHODS: The compensatory treatment of two patients, using Capelozza's individualized brackets, works as the scenery for cephalometric evaluation of changes in incisor inclination produced by different dimensions of leveling archwires. RESULTS: The evaluation of these cases showed that, while the introduction of a 0.019 x 0.025-in stainless steel archwire in a 0.022 x 0.030-in slot did not produce significant changes in incisor inclination, the 0.021 x 0.025-in archwire was capable of changing it, mainly in mandibular incisors, and in the opposite direction to the compensation. CONCLUSION: Considering compensatory treatments, even when using an individualized prescription according to the malocclusion, the bracket/wire play seems to be a positive factor for malocclusion correction, without undesirable movements. Therefore, it seems reasonable to admit that, until a bracket system can have absolute individualization, the use of rectangular wires that still have a certain play with the bracket slot is advisable.INTRODUÇÃO: a opinião sobre o conceito Straight-Wire tem evoluído desde sua origem, caracterizada por seguidores fiéis ou ceticismo absoluto. Atualmente, parece razoável acreditar que a maioria dos profissionais tem uma visão mais

  17. Clinical and microbiological parameters in patients with self-ligating and conventional brackets during early phase of orthodontic treatment.

    Science.gov (United States)

    Pejda, Slavica; Varga, Marina Lapter; Milosevic, Sandra Anic; Mestrovic, Senka; Slaj, Martina; Repic, Dario; Bosnjak, Andrija

    2013-01-01

    To determine the effect of different bracket designs (conventional brackets and self-ligating brackets) on periodontal clinical parameters and periodontal pathogens in subgingival plaque. The following inclusion criteria were used: requirement of orthodontic treatment plan starting with alignment and leveling, good general health, healthy periodontium, no antibiotic therapy in the previous 6 months before the beginning of the study, and no smoking. The study sample totaled 38 patients (13 male, 25 female; mean age, 14.6 ± 2.0 years). Patients were divided into two groups with random distribution of brackets. Recording of clinical parameters was done before the placement of the orthodontic appliance (T0) and at 6 weeks (T1), 12 weeks (T2), and 18 weeks (T3) after full bonding of orthodontic appliances. Periodontal pathogens of subgingival microflora were detected at T3 using a commercially available polymerase chain reaction test (micro-Dent test) that contains probes for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola. There was a statistically significant higher prevalence of A actinomycetemcomitans in patients with conventional brackets than in patients with self-ligating brackets, but there was no statistically significant difference for other putative periodontal pathogens. The two different types of brackets did not show statistically significant differences in periodontal clinical parameters. Bracket design does not seem to have a strong influence on periodontal clinical parameters and periodontal pathogens in subgingival plaque. The correlation between some periodontal pathogens and clinical periodontal parameters was weak.

  18. Effect of clearfil protect bond and transbond plus self-etch primer on shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    S Hamid Raji

    2011-01-01

    Conclusion: The shear bond strength of clearfil protect bond and transbond plus self-etch primer was enough for bonding the orthodontic brackets. The mode of failure of bonded brackets with these two self-etch primers is safe for enamel.

  19. A comparison of finite element analysis with in vitro bond strength tests of the bracket-cement-enamel system

    NARCIS (Netherlands)

    Algera, T.J.; Feilzer, A.J.; Prahl-Andersen, B.; Kleverlaan, C.J.

    2011-01-01

    The aim of this study was to determine the in vitro shear bond strength (SBS) and tensile bond strength (TBS) of 45 metal brackets bonded with Transbond XT to bovine enamel. The SBS was determined by loading the short and the long sides of the bracket base. Testing took place after storage of the

  20. [Epidemics of schistosomiasis in military staff assigned to endemic areas: standard diagnostic techniques and the development of real-time PCR techniques].

    Science.gov (United States)

    Biance-Valero, E; De Laval, F; Delerue, M; Savini, H; Cheinin, S; Leroy, P; Soullié, B

    2013-05-01

    The authors report the results of molecular biology techniques for the early diagnosis of cases (invasion phase) of schistosomiasis during two epidemics occurring during French military projects in the Central African Republic and Madagascar. The use of these techniques in real time for subjects not residing in the endemic area significantly improves the sensitivity of screening. The attack rates of these episodes, according to a case definition that took positive specific PCR results into account, were 59% and 26%. These results are a concrete illustration of the proverb that "yaws begin where the trail stops".

  1. Improvement of security techniques and protection of biometric data in biometric systems: Presentation of International Standard ISO 24745

    OpenAIRE

    Milinković, Milorad

    2017-01-01

    This paper presents the International Standard ISO 24745 as a potential security tool for biometric information protection, more precisely as a tool for privacy protection in biometric systems. This is one of the latest internationally accepted standards that address the security issues of biometric systems.

  2. Bonding polycarbonate brackets to ceramic: : Effects of substrate treatment on bond strength

    NARCIS (Netherlands)

    Özcan, Mutlu; Vallittu, Pekka K.; Peltomäki, Timo; Huysmans, Marie-Charlotte; Kalk, Warner

    2004-01-01

    This study evaluated the effects of 5 different surface conditioning methods on the bond strength of polycarbonate brackets bonded to ceramic surfaces with resin based cement. Six disc-shaped ceramic specimens (feldspathic porcelain) with glazed surfaces were used for each group. The specimens were

  3. On the equivalence of convergent kinetic equations for hot dilute plasmas: Generating functions for collision brackets

    NARCIS (Netherlands)

    Cohen, J.S.; Suttorp, L.G.

    1982-01-01

    The generating functions for the collision brackets associated with two alternative convergent kinetic equations are derived for small values of the plasma parameter. It is shown that the first few terms in the asymptotic expansions of these generating functions are identical. Consequently, both

  4. Onzichtbare orthodontie : Vacuümgevormde apparatuur, linguale apparatuur en keramische brackets

    NARCIS (Netherlands)

    van der Kaaij, N.C.W.; Zuurbier, P.C.M.

    2016-01-01

    Voor volwassenen die de stap nemen om zich orthodontisch te laten behandelen zijn er drie esthetische mogelijkheden naast de conventionele metalen brackets. 1) Vacuümgevormde apparatuur, waarbij met een set aligners de juiste tandstand wordt bereikt. Ze zijn comfortabel en nauwelijks zichtbaar, maar

  5. Assessment of the dimensions and surface characteristics of orthodontic wires and bracket slots.

    Science.gov (United States)

    Dolci, Gabriel Schmidt; Spohr, Ana Maria; Zimmer, Eduardo Rigon; Marchioro, Ernani Menezes

    2013-01-01

    The purpose of this study was to evaluate the dimensions and surface characteristics of orthodontic wires and bracket slots of different commercial brands. Thirty metallic brackets (0.022 x 0.028-in and 0.022 x 0.030-in) were divided into three groups: DYN/3M group = Dyna-Lock, 3M/Unitek (stainless steel, or SS); STD/MO group = Slim Morelli (SS); and Ni-Free/MO group = Slim Morelli (Ni-Free). The stainless steel wires (0.019 x 0.025-in) were divided into two groups: MO group = Morelli; and 3M group = 3M/Unitek. The bracket and wire measurements were done by two methods: (a) Surface Electron Microscopy (SEM), and (b) Profile Projection. The surface analysis was done qualitatively, based on SEM images and/or by a rugosimeter. The quantitative results were analyzed by ANOVA with Tukey's test (p wires, groups showed statistically different mean heights. It was concluded that wires and brackets slots can present altered dimensions, which might directly and unintentionally affect the planned tooth movement.

  6. Dirichlet-Neumann bracketing for boundary-value problems on graphs

    Directory of Open Access Journals (Sweden)

    Sonja Currie

    2005-08-01

    Full Text Available We consider the spectral structure of second order boundary-value problems on graphs. A variational formulation for boundary-value problems on graphs is given. As a consequence we can formulate an analogue of Dirichlet-Neumann bracketing for boundary-value problems on graphs. This in turn gives rise to eigenvalue and eigenfunction asymptotic approximations.

  7. Effect of Enamel Preparation and Light Curing Methods on Microleakage under Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Hamidreza Pakshir

    2015-11-01

    Full Text Available Objectives: This study aimed to compare the microleakage beneath metallic brackets following two different methods of enamel preparation and light curing.Materials and Methods: A total of 120 bovine deciduous lower incisors were randomly divided into four groups of 30 teeth. The preparations were as follows: Group I: Acid etching + Transbond XT primer + direct illumination, group II: acid etching + Transbond XT primer + transillumination, group III: Transbond XT self-etching primer + direct illumination and Group IV: Transbond XT self-etching primer + transillumination. Dye penetration was used as the method of microleakage evaluation. Sections made at the enamel-adhesive and adhesive-bracket interfaces were evaluated under a stereomicroscope. The Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. The level of significance was set at P<0.05.Results: All groups showed greater microleakage at the gingival in comparison to the incisal margin and the differences were significant among groups with transillumination (P<0.001. No significant differences were observed in the microleakage scores at the gingival and incisal margins in any of the interfaces (P>0.05. Mesiodistal margins of the self-etching group with direct illumination showed significantly lower scores in comparison with acid etched group (P<0.05.Conclusion: Use of self-etching primers for bonding of orthodontic brackets yields acceptable results if all bracket margins are cured directly.

  8. Dental Hygiene and Orthodontics: Effect of Ultrasonic Instrumentation on Bonding Efficacy of Different Lingual Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Andrea Scribante

    2017-01-01

    Full Text Available Dental hygienists are often faced with patients wearing lingual orthodontic therapy, as ultrasonic instrumentation (UI is crucial for oral health. As the application of external forces can lead to premature bonding failure, the aim of this study was to evaluate the effect of UI on shear bond strength (SBS and on adhesive remnant index (ARI of different lingual orthodontic brackets. 200 bovine incisors were divided into 10 groups. Four different lingual (STB, Ormco; TTR, Rocky Mountain Orthodontics; Idea, Leone; 2D, Forestadent and vestibular control (Victory, 3M brackets were bonded. UI was performed in half of specimens, whereas the other half did not receive any treatment. All groups were tested with a universal testing machine. SBS and ARI values were recorded. Statistical analysis was performed (significance: P=0.05. TTR, Idea, and 2D lingual brackets significantly lowered SBS after UI, whereas for other braces no effect was recorded. Appliances with lower mesh area significantly reduced their adhesion capacity after UI. Moreover groups subjected to UI showed higher ARI scores than controls. UI lowered SBS of lingual appliances of small dimensions so particular care should be posed avoiding prolonged instrumentation around bracket base during plaque removal. Moreover, UI influenced also ARI scores.

  9. Comparison of clinical bracket point registration with 3D laser scanner and coordinate measuring machine.

    Science.gov (United States)

    Nouri, Mahtab; Farzan, Arash; Baghban, Ali Reza Akbarzadeh; Massudi, Reza

    2015-01-01

    The aim of the present study was to assess the diagnostic value of a laser scanner developed to determine the coordinates of clinical bracket points and to compare with the results of a coordinate measuring machine (CMM). This diagnostic experimental study was conducted on maxillary and mandibular orthodontic study casts of 18 adults with normal Class I occlusion. First, the coordinates of the bracket points were measured on all casts by a CMM. Then, the three-dimensional coordinates (X, Y, Z) of the bracket points were measured on the same casts by a 3D laser scanner designed at Shahid Beheshti University, Tehran, Iran. The validity and reliability of each system were assessed by means of intraclass correlation coefficient (ICC) and Dahlberg's formula. The difference between the mean dimension and the actual value for the CMM was 0.0066 mm. (95% CI: 69.98340, 69.99140). The mean difference for the laser scanner was 0.107 ± 0.133 mm (95% CI: -0.002, 0.24). In each method, differences were not significant. The ICC comparing the two methods was 0.998 for the X coordinate, and 0.996 for the Y coordinate; the mean difference for coordinates recorded in the entire arch and for each tooth was 0.616 mm. The accuracy of clinical bracket point coordinates measured by the laser scanner was equal to that of CMM. The mean difference in measurements was within the range of operator errors.

  10. Effect of alloy type and surface conditioning on roughness and bond strength of metal brackets

    NARCIS (Netherlands)

    Nergiz, I.; Schmage, P.; Herrmann, W.; Ozcan, M.; Nergiz, [No Value

    2004-01-01

    The effect of 5 different surface conditioning methods on bonding of metal brackets to cast dental alloys was examined. The surface conditioning methods were fine (30-µm) or rough (125-µm) diamond bur, sandblasting (50-µm or 110-µm aluminum oxide [Al2O3]), and silica coating (30-µm silica). Fifty

  11. Evaluation of spectrographic standards for the carrier-distillation analysis of PuO2

    International Nuclear Information System (INIS)

    Martell, C.J.; Myers, W.M.

    1976-05-01

    Three plutonium metals whose impurity contents have been accurately determined are used to evaluate spectrographic standards. Best results are obtained when (1) highly impure samples are diluted, (2) the internal standard, cobalt, is used, (3) a linear curve is fitted to the standard data that bracket the impurity concentration, and (4) plutonium standards containing 22 impurities are used

  12. Duration of Hemodialysis Following Peritoneal Dialysis Cessation in Australia and New Zealand: Proposal for a Standardized Definition of Technique Failure.

    Science.gov (United States)

    Lan, Patrick G; Clayton, Philip A; Johnson, David W; McDonald, Stephen P; Borlace, Monique; Badve, Sunil V; Sud, Kamal; Boudville, Neil

    ♦ BACKGROUND: Although technique failure is a key outcome in peritoneal dialysis (PD), there is currently no agreement on a uniform definition. We explored different definitions of PD technique failure using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. ♦ METHODS: We included 16,612 incident PD patients in Australia and New Zealand from January 1998 to December 2012. Different definitions of technique failure were applied according to the minimum number of days (30, 60, 90, 180, or 365) the patient received hemodialysis after cessation of PD. ♦ RESULTS: Median technique survival varied from 2.0 years with the 30-day definition to 2.4 years with the 365-day definition. For all definitions, the most common causes of technique failure were death, followed by infectious complications. The likelihood of a patient returning to PD within 12 months of technique failure was highest in the 30-day definition (24%), and was very small when using the 180- and 365-day definitions (3% and 0.8%, respectively). Patients whose technique failed due to mechanical reasons were the most likely to return to PD (46% within 12 months using the 30-day definition). ♦ CONCLUSIONS: Both 30- and 180-day definitions have clinical relevance but offer different perspectives with very different prognostic implications for further PD. Therefore, we propose that PD technique failure be defined by a composite endpoint of death or transfer to hemodialysis using both 30-day and 180-day definitions. Copyright © 2016 International Society for Peritoneal Dialysis.

  13. Effect of Surface Treatment on Enamel Cracks after Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching versus Acid-Etching

    Directory of Open Access Journals (Sweden)

    Hassanali Ghaffari

    2017-12-01

    Full Text Available Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG laser and the conventional acid-etching technique.Materials and Methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30. The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60µs, 80% water and 60% air. Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene’s test was applied to assess the equality of variances.Results: No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05.Conclusions: Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions, Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding.  

  14. Static and kinetic frictional forces of silica-insert ceramic brackets with coated archwires in artificial saliva.

    Science.gov (United States)

    Shahabi, Mostafa; Salari, Soheil; Poosti, Maryam; Abtahi, Mostafa

    2017-01-01

    During sliding mechanics, the frictional force (FF) is an important counterforce to orthodontic tooth movement. The purpose of this in vitro study was to investigate the static and kinetic FFs of S silica-insert ceramic (SIC) brackets with Teflon-coated (TC) and conventional S stainless steel (SS) archwires. The target group of this study included 80 maxillary canine 0.022 inch slot SIC brackets. Forty SS brackets were used as the control. TC and conventional uncoated SS archwires of different dimensions (0.016, 0.018, 0.016 × 0.022, and 0.018 × 0.025 inch) were examined. All tests were carried out under artificial saliva injected condition. Scanning Electron Micrographs were prepared for two samples of coated and uncoated archwires. Analysis of variance and Tukey post hoc tests were used for statistical purposes (level of significance P < 0.05). SIC brackets showed significantly lower levels of FFs than SS brackets. TC archwires had greater frictional values than conventional uncoated ones. They also exhibited an unusual behavior of increasing kinetic FFs with time. Indentation and delamination of coating were obvious under scanning electron microscopy observations. From the standpoint of friction, SIC brackets may serve well, even better than SS brackets, in sliding mechanics. The coating layer of the archwires may delaminate and lost, causing an impediment to tooth movement.

  15. PERBANDINGAN TEKNIS DAN EKONOMIS ANTARA PENGGANTIAN BANTALAN POROS PROPELLER DIBANDINGKAN DENGAN PENGGESERAN POSISI V-BRACKET PADA KMP. KUMALA

    Directory of Open Access Journals (Sweden)

    Untung Budiarto

    2012-02-01

    Full Text Available In the propulsion systems there are three preference components main engine, propeller shaft, and propeller.KMP. Kumala is one for all passengers ship the owner PT. Darma Lautan Utama, there are it’s to experienceproblems to the systems propulsion to happen missalignment between construction v-bracket with sterntube,there are v-bracket to function become to hold up propeller shaft in the inside to find shaft bearing. Effect themissalignment, shaft can’t to turn, so need the realized preparing with the change to shaft bearing shapeexentric and to scrape position v-bracket the position again. In this finish task purporting to know the valuefrom side technics and economics between to realized the change shaft bearing shape exentric with to scrapeposition v-bracket to position again with account time to docking next time. From the result analyse to find thatto change the shaft bearing shape exentric to need faster time, material cost is more expensive, labour cost ischeaper, construction to v-bracket isn’t normaly, than to scrape position v-bracket to need the time is long time,material cost is cheaper, job cost is more expensive, construction v-bracket back to normal the position again,until to moment realization docking next time to need faster time, material cost and job cost is cheaper from tochange the shaft bearing shape exentric.

  16. Evaluation of the force generated by gradual deflection of orthodontic wires in conventional metallic, esthetic, and self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Manoela Fávaro Francisconi

    Full Text Available ABSTRACT Objective: The purpose of this study was to evaluate the deflection forces of Nitinol orthodontic wires placed in different types of brackets: metallic, reinforced polycarbonate with metallic slots, sapphire, passive and active self-ligating, by assessing strength values variation according to gradual increase in wire diameter and deflection and comparing different combinations in the different deflections. Material and Methods: Specimens were set in a clinical simulation model and evaluated in a Universal Testing Machine (INSTRON 3342, using the ISO 15841 protocol. Data were subjected to One-way ANOVA, followed by Tukey tests (p<0.05. Results: Self-ligating brackets presented the most similar behavior to each other. For conventional brackets there was no consistent behavior for any of the deflections studied. Conclusions: Self-ligating brackets presented the most consistent and predictable results while conventional brackets, as esthetic brackets, showed very different patterns of forces. Self-ligating brackets showed higher strength in all deflections when compared with the others, in 0.020-inch wires.

  17. Unreamed intramedullary nailing of femoral shaft fractures: operative technique and early clinical experience with the standard locking option.

    Science.gov (United States)

    Krettek, C; Rudolf, J; Schandelmaier, P; Guy, P; Könemann, B; Tscherne, H

    1996-05-01

    Nailing techniques have changed in recent years in ways which are not just limited to omitting the reaming process. These changes concern positioning patients, techniques of reduction and selecting implants. Techniques of approach and exposure have been modified to new, less-invasive procedures to fulfill technical, functional and cosmetic requirements. In addition, techniques have been developed to avoid fragment diastasis, rotational and sagittal malalignment, and leg-length discrepancy. Finally, simple algorithms have been elaborated for the management of specific fracture patterns (bilateral shaft fractures, ipsilateral tibial fractures or associated femoral neck fractures) and to determine the number and location of locking bolts. We developed these algorithms, techniques and procedures in a series of 133 femoral shafts, which were stabilized with the AO unreamed femoral nail (URFN) in a prospective study between 1991 and 1994. Of these, the first 57 cases with a mean follow-up of 17.9 months (range, 5-44) after injury were reviewed. Fractures were classified according to Müller's 1990 system: 12 type A, 29 type B and 16 type C. Closed soft-tissue injuries were classified by our classification of 1982: 17 type C 0/I, 42 type C II. Of 15 open fractures, six were OI, six OII, two OIIIA and one was OIIIB by Gustilo's classification of 1984. The major complications were two broken locking bolts, one nail breaking after 9 weeks, one case of osteitis and one of intra-operative lung embolism.

  18. Deproteinization of tooth enamel surfaces to prevent white spot lesions and bracket bond failure: A revolution in orthodontic bonding

    Directory of Open Access Journals (Sweden)

    Roberto Justus

    2016-01-01

    Full Text Available Orthodontic treatment success is jeopardized by the risk of development of white spot lesions (WSLs around orthodontic brackets. Unfortunately, the formation of WSLs still remains a common complication during treatment in patients with poor oral hygiene. Nearly 75% of orthodontic patients are reported to develop enamel decalcification because of prolonged plaque retention around brackets. It is the orthodontist′s responsibility to minimize the risk of patients having enamel decalcifications as a consequence of orthodontic treatment. This can be achieved by using hybrid, fluoride-releasing, glass ionomer cement to bond brackets, with deproteinization of the enamel surface before phosphoric acid etching.

  19. A Technique for Standardized Evaluation of Soft and Hard Peri-Implant Tissues in Partially Edentulous Patients

    NARCIS (Netherlands)

    Meijndert, Leo; Meijer, Henny J.A.; Raghoebar, Gerry M.; Vissink, Arjan

    Background: There is a growing need to evaluate the esthetics of implant-supported crowns and bridges. An important tool for such an evaluation is standardized assessment of the soft and hard peri-implant tissue levels. Methods: A simple acrylic device has been developed for reliable and

  20. Slit-scanning technique using standard cell sorter instruments for analyzing and sorting nonacrocentric human chromosomes, including small ones

    NARCIS (Netherlands)

    Rens, W.; van Oven, C. H.; Stap, J.; Jakobs, M. E.; Aten, J. A.

    1994-01-01

    We have investigated the performance of two types of standard flow cell sorter instruments, a System 50 Cytofluorograph and a FACSTar PLUS cell sorter, for the on-line centromeric index (CI) analysis of human chromosomes. To optimize the results, we improved the detection efficiency for centromeres

  1. Comparación de la Respuesta Biológica generada por un sistema de brackets Convencional y brackets de Autoligado.

    OpenAIRE

    Wilches Buitrago, Liseth; Pontificia Universidad Javeriana; García, Adriana; Pontificia Universidad Javeriana; Quintero, Lina; Pontificia Universidad Javeriana; De Los Reyes, Alfonso; Pontificia Universidad Javeriana; Otero, Liliana; Pontificia Universidad Javeriana

    2014-01-01

    Antecedentes: No existe evidencia científica suficiente que soporte las ventajas del sistema de fuerzas de autoligado sobre el sistema de fuerzas convencional en ortodoncia. El objetivo de esta investigación  fue Comparar la expresión de OPG y RANKL en el ligamento periodontal de dientes sometido a fuerzas ortodóncicas generadas por un sistema de brackets de autoligado y un sistema convencional. Materiales y Métodos: Se analizó  la expresión de OPG y RANKL mediante RT-PCR en el  ligamento per...

  2. Strain analysis in CRT candidates using the novel segment length in cine (SLICE) post-processing technique on standard CMR cine images.

    Science.gov (United States)

    Zweerink, Alwin; Allaart, Cornelis P; Kuijer, Joost P A; Wu, LiNa; Beek, Aernout M; van de Ven, Peter M; Meine, Mathias; Croisille, Pierre; Clarysse, Patrick; van Rossum, Albert C; Nijveldt, Robin

    2017-12-01

    Although myocardial strain analysis is a potential tool to improve patient selection for cardiac resynchronization therapy (CRT), there is currently no validated clinical approach to derive segmental strains. We evaluated the novel segment length in cine (SLICE) technique to derive segmental strains from standard cardiovascular MR (CMR) cine images in CRT candidates. Twenty-seven patients with left bundle branch block underwent CMR examination including cine imaging and myocardial tagging (CMR-TAG). SLICE was performed by measuring segment length between anatomical landmarks throughout all phases on short-axis cines. This measure of frame-to-frame segment length change was compared to CMR-TAG circumferential strain measurements. Subsequently, conventional markers of CRT response were calculated. Segmental strains showed good to excellent agreement between SLICE and CMR-TAG (septum strain, intraclass correlation coefficient (ICC) 0.76; lateral wall strain, ICC 0.66). Conventional markers of CRT response also showed close agreement between both methods (ICC 0.61-0.78). Reproducibility of SLICE was excellent for intra-observer testing (all ICC ≥0.76) and good for interobserver testing (all ICC ≥0.61). The novel SLICE post-processing technique on standard CMR cine images offers both accurate and robust segmental strain measures compared to the 'gold standard' CMR-TAG technique, and has the advantage of being widely available. • Myocardial strain analysis could potentially improve patient selection for CRT. • Currently a well validated clinical approach to derive segmental strains is lacking. • The novel SLICE technique derives segmental strains from standard CMR cine images. • SLICE-derived strain markers of CRT response showed close agreement with CMR-TAG. • Future studies will focus on the prognostic value of SLICE in CRT candidates.

  3. Strain analysis in CRT candidates using the novel segment length in cine (SLICE) post-processing technique on standard CMR cine images

    Energy Technology Data Exchange (ETDEWEB)

    Zweerink, Alwin; Allaart, Cornelis P.; Wu, LiNa; Beek, Aernout M.; Rossum, Albert C. van; Nijveldt, Robin [VU University Medical Center, Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), Amsterdam (Netherlands); Kuijer, Joost P.A. [VU University Medical Center, Department of Physics and Medical Technology, Amsterdam (Netherlands); Ven, Peter M. van de [VU University Medical Center, Department of Epidemiology and Biostatistics, Amsterdam (Netherlands); Meine, Mathias [University Medical Center, Department of Cardiology, Utrecht (Netherlands); Croisille, Pierre; Clarysse, Patrick [Univ Lyon, UJM-Saint-Etienne, INSA, CNRS UMR 5520, INSERM U1206, CREATIS, Saint-Etienne (France)

    2017-12-15

    Although myocardial strain analysis is a potential tool to improve patient selection for cardiac resynchronization therapy (CRT), there is currently no validated clinical approach to derive segmental strains. We evaluated the novel segment length in cine (SLICE) technique to derive segmental strains from standard cardiovascular MR (CMR) cine images in CRT candidates. Twenty-seven patients with left bundle branch block underwent CMR examination including cine imaging and myocardial tagging (CMR-TAG). SLICE was performed by measuring segment length between anatomical landmarks throughout all phases on short-axis cines. This measure of frame-to-frame segment length change was compared to CMR-TAG circumferential strain measurements. Subsequently, conventional markers of CRT response were calculated. Segmental strains showed good to excellent agreement between SLICE and CMR-TAG (septum strain, intraclass correlation coefficient (ICC) 0.76; lateral wall strain, ICC 0.66). Conventional markers of CRT response also showed close agreement between both methods (ICC 0.61-0.78). Reproducibility of SLICE was excellent for intra-observer testing (all ICC ≥0.76) and good for interobserver testing (all ICC ≥0.61). The novel SLICE post-processing technique on standard CMR cine images offers both accurate and robust segmental strain measures compared to the 'gold standard' CMR-TAG technique, and has the advantage of being widely available. (orig.)

  4. Comparison of frictional resistance among conventional, active and passive selfligating brackets with different combinations of arch wires: a finite elements study.

    Science.gov (United States)

    Gómez, Sandra L; Montoya, Yesid; Garcia, Nora L; Virgen, Ana L; Botero, Javier E

    2016-09-01

    The aim of this study was to compare frictional resistance among conventional, passive and active selfligating brackets using Finite Elements Analysis (FEA). Seventynine (79) slide tests were performed by combining an upper first bicuspid conventional bracket, 0.018" stainless steel wires and 0.010" ligature by means of an INSTRON 3345 load system to obtain average maximum static frictional resistance (MSFR). This value was compared to the FR (frictional resistance) obtained by simulation of a slide of the same combination by FEA following conventional bracket modeling by means of Computer Aided Design (CAD). Once the FEA was validated, bracket CADs were designed (upper right first bicuspid conventional, active and passive selfligating bracket) and bracket properties calculated. MSFR was compared among conventional, active and passive selfligating brackets with different alloys and archwire cross sections such as 0.018", 0.019" x 0.025"and 0.020" x 0.020". Passive selfligating brackets had the lowest MSFR, followed by conventional brackets and active selfligating brackets. In conventional brackets, a 0.018" archwire produced a linear pattern of stress with maximum concentration at the center. Conversely, stress in 0.020 x 0.020" and 0.019 x 0.025" archwires was distributed across the width of the slot. The highest normal forces were 1.53 N for the 0.018" archwire, 4.85 N for the 0.020 x 0.020" archwire and 8.18 N for the 0.019 x 0.025" archwire. Passive selfligating brackets presented less frictional resistance than conventional and active selfligating brackets. Regardless of bracket type, greater contact area between the slot and the archwire and the spring clip increased frictional resistance. Sociedad Argentina de Pediatría.

  5. Comparison of Bond Strength of Brackets with Foil Mesh and Laser Structure Base using Light Cure Composite Resin: An in vitro Study.

    Science.gov (United States)

    Rajesh, R N G; Girish, K S; Sanjay, N; Scindhia, Rajath D; Kumar, Sujay G; Rajesh, Suchitra

    2015-12-01

    The purpose of this in vitro study was to evaluate the bond strength of the laser-etched base bracket, site of bond failure, and evaluate for enamel remnants on the bracket base after debonding, when compared to foil mesh base bracket. Sixty noncarious, human premolar extracted for the orthodontic treatment were used for this study. The teeth were randomly divided into two groups containing 30 teeth each, which were bonded with laser-etched base bracket and mesh base bracket using light cure resin. The tensile and mechanical bond strength was tested after 24 hours using TIRA. The forces recorded during debonding were measured in Newton and final readings were tabulated in megapascals (MPa). After debonding, the amount of residual adhesive and enamel detachment on the bracket base were assessed according to adhesive remnant index (ARI) and enamel detachment index (EDI) using stereomicroscope and energy dispersive X-ray spectrometer. The laser-etched base bracket showed statistically significant higher results than mesh base bracket. Mann-Whitney test indicated that laser-etched base bracket had significantly higher tensile bond strength of 8.47 MPa (SD ± 0.84), fatigue strength of 7.75 MPa (SD ± 0.79) compared to mesh base bracket with tensile bond strength of 5.53 Mpa (SD ± 0.89) and fatigue strength of 5.17 MPa (SD ± 1.15). Adhesive remnant index score indicated that laser-etched base bracket had ARI score of 3 for most of the bracket, when compared to mesh base bracket. This was statistically significant. Enamel detachment index scores indicated that less than 10% of enamel detachment occurred in both the types of brackets, which was not statistically significant. Laser-etched base bracket showed superior bond strength, when compared to the foil mesh base bracket. The site of bond failure of these laser-etched base bracket was at the interface of enamel-adhesive and did not induce any significant enamel detachment. Thus, we can conclude that laser-etched base

  6. An in vitro Evaluation of Friction Characteristics of Conventional Stainless Steel and Self-ligating Stainless Steel Brackets with different Dimensions of Archwires in Various Bracket-archwire Combination.

    Science.gov (United States)

    Sridharan, K; Sandbhor, Shailesh; Rajasekaran, U B; Sam, George; Ramees, M Mohamed; Abraham, Esther A

    2017-08-01

    The purpose of this research is to compare the frictional attributes of stainless steel conventional brackets and self-ligating stainless steel brackets with different dimensions of archwires. The test was carried with two sets of maxillary brackets: (1) Conventional stainless steel (Victory Series), (2) stainless steel self-ligating (SmartClip) without first premolar brackets. Stainless steel, nickel-titanium (NiTi), and beta-Ti which are the types of orthodontic wire alloys were tested in this study. To monitor the frictional force, a universal testing machine (Instron 33R 4467) that comprises 10 kg tension load cell was assigned on a range of 1 kg and determined from 0 to 2 kg, which allows moving of an archwire along the brackets. One-way analysis of variance was used to test the difference between groups. To analyze the statistical difference between the two groups, Student's t-test was used. For Victory Series in static friction, p-value was 0.946 and for kinetic friction it was 0.944; at the same time for SmartClip, the p value for static and kinetic frictional resistance was 0.497 and 0.518 respectively. Hence, there was no statistically significant difference between the NiTi and stainless steel archwires. It is concluded that when compared with conventional brackets with stainless steel ligatures, self-ligating brackets can produce significantly less friction during sliding. Beta-Ti archwires expressed high amount of frictional resistance and the stainless steel archwires comprise low frictional resistance among all the archwire materials. In orthodontics, frictional resistance has always had a major role. Its ability to impair tooth movement leads to the need for higher forces to move the teeth and it extends the treatment time which results in loss of posterior anchorage. Friction in orthodontics is related with sliding mechanics when a wire is moving through one or a series of bracket slots.

  7. Chemical Separation Technique of Strontium-90 in the Soil Water as theStandard Methods for Environmental Radioactivity Analysis

    International Nuclear Information System (INIS)

    Ngasifudin-Hamdani; Suratman; Djoko-Sardjono, Ign; Winduanto-Wahyu SP

    2000-01-01

    Research about separation technique of strontium-90 from its materialmatrix using chemical precipitation method has been done. That technique wasapplied on the detection of radionuclide strontium-90 containing in the soilwater of near nuclear reactor facility P3TM BATAN in three location. The twoimportant parameters used in this technique were growth time of Y-90 andstirring time. The result shown that activity of strontium-90 in the pos-01was between 1.801x10 -19 - 9.616x10 -17 μCi/cm 3 , pos-02 was8.448x10 -19 - 1.003x X 10 -16 μCi/cm 3 and pos-03 was 6.719x10 -19 - 11.644x10 -16 μCi/cm 3 . From those data shown that activity of Sr-90in the soil water of near nuclear reactor facility P3TM BATAN was still belowthe limit value of maximum concentration permitted i.e. 4.0x10 -7 -3.5x10 -6 μCi/cm 3 . The statistic test using analysis of varian twofactorial with random block design shown that the activity of Sr-90 in thesoil water was influenced by the interaction which take place between growthlong time of Y-90 and stirring long time. (author)

  8. [Western blot technique standardization for specific diagnosis of Chagas disease using excretory-secretory antigens of Trypanosoma cruzi epimastigotes].

    Science.gov (United States)

    Escalante, Hermes; Jara, César; Davelois, Kelly; Iglesias, Miguel; Benites, Adderly; Espinoza, Renzo

    2014-01-01

    Evaluate the effectiveness of Western Blot for the specific diagnosis of Chagas disease using excretory-secretory antigens of Trypanosoma cruzi epimastigotes. Antigens were obtained after twenty hours of incubation in Eagle’s Minimum Essential Medium, which were prepared at a protein concentration of 0.2 ug/uL to be faced with 10 mL pool of serum from patients with Chagas disease and a conjugated anti-IgG labeled with peroxidase. The presence of the following antigens was observed: 10, 12, 14, 15, 19, 20, 23, 26, 30, 33, 36, 40, 42, 46, 58, 63, 69, 91, 100, and 112 kDa; of which antigens of 10, 12, 14, 15, 19, 20, 23, and 26 kDa were considered to be specific using pools of serum from patients with other parasitosis and serum from people with no parasites. The sensitivity of the technique was assessed using individual serum from 65 patients with Chagas disease; and the specificity with serum from 40 patients with other parasitosis, and serums from five people who did not have parasites. The technique has a sensitivity of 95.4% in the detection of one to eight specific bands, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 93.7%. Western Blot technique with excretory-secretory antigens of T. cruzi epimastigotes is effective in the diagnosis of Chagas disease in Peru; therefore, it can be used as a confirmatory test.

  9. Report on COTECH test procedure and characterization techniques

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul

    .Characterization techniques and test procedure requirements for innovative self-ligating dental brackets (EO) Section 5.Characterization techniques and test procedure requirements for smart diagnostic chips comprising a microfluidic channel system (GBO) Section 6.Characterization techniques and test procedure...... requirements for multifunctional integrated lighting rear lamp for cars (CRP) Section 7.Characterization techniques and test procedure requirements for micro-fresnel lenses for cell phone flash lights (HEPTAGON) Section 8.Characterization techniques and test procedure requirements for 5 Pin Ric Connector...

  10. Influence of adhesion promoters and curing-light sources on the shear bond strength of orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Claudia Tavares Machado

    2012-01-01

    Conclusions: The conventional orthodontic adhesive presented higher bond strength than the nanofilled composite, although both materials interacted similarly to the teeth. The curing-light devices tested did not influence on bond strength of orthodontic brackets.

  11. Reduction in static friction by deposition of a homogeneous diamond-like carbon (DLC) coating on orthodontic brackets.

    Science.gov (United States)

    Akaike, Shun; Hayakawa, Tohru; Kobayashi, Daishiro; Aono, Yuko; Hirata, Atsushi; Hiratsuka, Masanori; Nakamura, Yoshiki

    2015-01-01

    In orthodontics, a reduction in static friction between the brackets and wire is important to enable easy tooth movement. The aim of this study was to examine the effects of a homogeneous diamond-like carbon (DLC) coating on the whole surfaces of slots in stainless steel orthodontic brackets on reducing the static friction between the brackets and the wire. The DLC coating was characterized using Raman spectroscopy, surface roughness and contact angle measurements, and SEM observations. Rectangular stainless steel and titanium-molybdenum alloy wires with two different sizes were employed, and the static friction between the brackets and wire was measured under dry and wet conditions. The DLC coating had a thickness of approximately 1.0 μm and an amorphous structure was identified. The results indicated that the DLC coating always led to a reduction in static friction.

  12. Combined use of miniscrews and clear appliances for the treatment of bialveolar protrusion without conventional brackets.

    Science.gov (United States)

    Choi, Nak-Chun; Park, Young-Chel; Jo, Yong-Min; Lee, Kee-Joon

    2009-05-01

    The increasing demand for esthetic orthodontic treatment has led to the development of tooth-colored and even "invisible" appliances. Although sequential removable clear aligners have several advantages over conventional bracket systems, they have some limitations in extraction treatment. This case report presents the esthetic extraction treatment of a patient with bialveolar protrusion; conventional brackets were not used. The treatment was completed in 2 steps. The first step involved segmental retraction of the anterior teeth by using miniscrews and an anterior lingual splint with a clear lever arm. The second step involved alignment and finishing by using sequential removable clear aligners. The patient's esthetic demands were fulfilled successfully during treatment, and satisfactory facial profile and occlusion were achieved after treatment.

  13. Comparison of frictional forces between aesthetic orthodontic coated wires and self-ligation brackets.

    Science.gov (United States)

    Kim, Yunmi; Cha, Jung-Yul; Hwang, Chung-Ju; Yu, Hyung Seog; Tahk, Seon Gun

    2014-07-01

    The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. 0.016-inch nickel titanium (NiTi) wires and 0.017 × 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0°, 5°, and 10°. Upper maxillary premolar brackets (Clippy-C®) with a 0.022-inch slot were selected for the study and a tensile test was performed with a crosshead speed of 5 mm/min. The maximum static frictional forces and kinetic frictional forces were recorded and compared. The maximum static frictional forces and the kinetic frictional forces of coated wires were equal to or higher than those of the uncoated wires (p forces of rhodium-coated wires were significantly higher than those of polymer-coated wires when the angulations between the brackets and wires were set to (i) 5° in the 0.016-inch NiTi wires and (ii) all angulations in the 0.017 × 0.025-inch SS wires (p kinetic frictional forces of rhodium-coated wires were higher than those of polymer-coated wires, except when the angulations were set to 0° in the 0.016-inch NiTi wires (p forces of the coated wires with regards to aesthetics were equal to or greater than those of the uncoated wires, a study under similar conditions regarding the oral cavity is needed in order to establish the clinical implications.

  14. Effect of different concentrations of papain gel on orthodontic bracket bonding

    OpenAIRE

    Pithon, Matheus M; Ferraz, Caio S; Oliveira, Gabriel D Couto; Santos, Adrielle M Dos

    2013-01-01

    Background The objective of this study was to verify the hypothesis that enamel deproteinization with papain gel at concentrations of 2%, 4%, 6%, 8%, and 10% increases shear bond strength as concentration increases. Methods A total of 180 bovine mandibular permanent incisors were used, divided into six groups (n = 30), and denominated as follows: group 1 is the control group (CG) in which brackets are bonded with resin-modified glass ionomer cement (RMGIC) according to the manufacturer's reco...

  15. Symplectic matrix, gauge invariance and Dirac brackets for super-QED

    Energy Technology Data Exchange (ETDEWEB)

    Alves, D.T. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Cheb-Terrab, E.S. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Mathematics

    1999-08-01

    The calculation of Dirac brackets (DB) using a symplectic matrix approach but in a Hamiltonian framework is discussed, and the calculation of the DB for the supersymmetric extension of QED (super-QED) is shown. The relation between the zero-mode of the pre-symplectic matrix and the gauge transformations admitted by the model is verified. A general description to construct Lagrangians linear in the velocities is also presented. (author)

  16. Probability Bracket Notation: the Unified Expressions of Conditional Expectation and Conditional Probability in Quantum Modeling

    OpenAIRE

    Wang, Xing M.

    2009-01-01

    After a brief introduction to Probability Bracket Notation (PBN), indicator operator and conditional density operator (CDO), we investigate probability spaces associated with various quantum systems: system with one observable (discrete or continuous), system with two commutative observables (independent or dependent) and a system of indistinguishable non-interacting many-particles. In each case, we derive unified expressions of conditional expectation (CE), conditional probability (CP), and ...

  17. Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

    Science.gov (United States)

    Cumerlato, Marina; de Lima, Eduardo Martinelli; Osorio, Leandro Berni; Mota, Eduardo Gonçalves; de Menezes, Luciane Macedo; Rizzatto, Susana Maria Deon

    2017-01-01

    ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI. PMID:28902249

  18. Comparison of frictional forces between aesthetic orthodontic coated wires and self-ligation brackets

    Science.gov (United States)

    Kim, Yunmi; Cha, Jung-Yul; Hwang, Chung-Ju; Tahk, Seon Gun

    2014-01-01

    Objective The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. Methods 0.016-inch nickel titanium (NiTi) wires and 0.017 × 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0°, 5°, and 10°. Upper maxillary premolar brackets (Clippy-C®) with a 0.022-inch slot were selected for the study and a tensile test was performed with a crosshead speed of 5 mm/min. The maximum static frictional forces and kinetic frictional forces were recorded and compared. Results The maximum static frictional forces and the kinetic frictional forces of coated wires were equal to or higher than those of the uncoated wires (p wires were significantly higher than those of polymer-coated wires when the angulations between the brackets and wires were set to (i) 5° in the 0.016-inch NiTi wires and (ii) all angulations in the 0.017 × 0.025-inch SS wires (p wires were higher than those of polymer-coated wires, except when the angulations were set to 0° in the 0.016-inch NiTi wires (p wires with regards to aesthetics were equal to or greater than those of the uncoated wires, a study under similar conditions regarding the oral cavity is needed in order to establish the clinical implications. PMID:25133130

  19. Surface Modification of Orthodontic Bracket Models via Ion Implantation: Effect on Coefficients of Friction

    Science.gov (United States)

    1989-01-01

    was accomplished and tested against the four major orthodontic alloy groups, [stainless steel (S.S.), cobalt-chromium (Co-Cr), nickel-titanium ( NiTi ...premolar extraction case measured friction values as a bracket slid over an arch wire. To deliver a constant ligature force, a coil spring maintained...accomplished and tested against the four major orthodontic alloy groups, [stainless steel (S.S.), cobalt-chromium (Co-Cr), nickel-titanium ( NiTi

  20. Comparison of clinical bracket point registration with 3D laser scanner and coordinate measuring machine

    Directory of Open Access Journals (Sweden)

    Mahtab Nouri

    2015-02-01

    Full Text Available OBJECTIVE: The aim of the present study was to assess the diagnostic value of a laser scanner developed to determine the coordinates of clinical bracket points and to compare with the results of a coordinate measuring machine (CMM. METHODS: This diagnostic experimental study was conducted on maxillary and mandibular orthodontic study casts of 18 adults with normal Class I occlusion. First, the coordinates of the bracket points were measured on all casts by a CMM. Then, the three-dimensional coordinates (X, Y, Z of the bracket points were measured on the same casts by a 3D laser scanner designed at Shahid Beheshti University, Tehran, Iran. The validity and reliability of each system were assessed by means of intraclass correlation coefficient (ICC and Dahlberg's formula. RESULTS: The difference between the mean dimension and the actual value for the CMM was 0.0066 mm. (95% CI: 69.98340, 69.99140. The mean difference for the laser scanner was 0.107 ± 0.133 mm (95% CI: -0.002, 0.24. In each method, differences were not significant. The ICC comparing the two methods was 0.998 for the X coordinate, and 0.996 for the Y coordinate; the mean difference for coordinates recorded in the entire arch and for each tooth was 0.616 mm. CONCLUSION: The accuracy of clinical bracket point coordinates measured by the laser scanner was equal to that of CMM. The mean difference in measurements was within the range of operator errors.

  1. Does the CO2 laser reduce bond strength in different types of ceramic brackets?

    Directory of Open Access Journals (Sweden)

    Fábio Lourenço Romano

    Full Text Available ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A; Transcend (T. Each group was divided into 2 subgroups (n = 15: L, laser (10W, 3s; C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05. RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3. TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

  2. Single interval longwave radiation scheme based on the net exchanged rate decomposition with bracketing

    Czech Academy of Sciences Publication Activity Database

    Geleyn, J.- F.; Mašek, Jan; Brožková, Radmila; Kuma, P.; Degrauwe, D.; Hello, G.; Pristov, N.

    2017-01-01

    Roč. 143, č. 704 (2017), s. 1313-1335 ISSN 0035-9009 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : numerical weather prediction * climate models * clouds * parameterization * atmospheres * formulation * absorption * scattering * accurate * database * longwave radiative transfer * broadband approach * idealized optical paths * net exchanged rate decomposition * bracketing * selective intermittency Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 3.444, year: 2016

  3. Mechanical properties of coated superelastic archwires in conventional and self-ligating orthodontic brackets

    OpenAIRE

    Elayyan, Firas; Silikas, Nick; Bearn, David

    2010-01-01

    Introduction: Coated archwires have been introduced to improve esthetics during orthodontic treatment. Our aim was to investigate the mechanical properties of coated superelastic archwires compared with conventional superelastic archwires with conventional and self-ligating brackets. Methods: Four types of orthodontic archwires were investigated, 2 superelastic nickel-titanium and 2 coated Ultraesthetic archwires in 0.016-in and 0.018 × 0.025-in dimensions (all from G&H Wire, Greenwood, I...

  4. The impact of chlorhexidine mouth rinse on the bond strength of polycarbonate orthodontic brackets.

    Science.gov (United States)

    Hussein, Farouk Ahmed; Hashem, Mohammed Ibrahim; Chalisserry, Elna P; Anil, Sukumaran

    2014-11-01

    The purpose of the current in-vivo study was to assess the effect of using 0.12% chlorhexidine (CHX) mouth rinse, before bonding, on shear bond strength of polycarbonate brackets bonded with composite adhesive. Eighteen orthodontic patients with a mean age 21.41 ± 1.2 years, who were scheduled to have 2 or more first premolars extracted, were included in this study. Patients were referred for an oral prophylaxis program which included, in part, the use of a mouth rinse. Patients were divided into 2 groups, a test group of 9 patients who used 0.12% CHX gluconate mouth rinse twice daily and a control group of 9 patients who used a mouth rinse without CHX, but with same color. After 1 week, polycarbonate brackets were bonded to first premolars with Transbond XT composite adhesive. Premolars were extracted after 28 days and tested for shear bond strength on a universal testing machine. Student's t-test was used to compare shear bond strengths of both groups. No statistically significant difference was found in bond strengths' values between both groups. The test group (with CHX) has mean shear bond strength of 14.21 ± 2.42 MPa whereas the control group (without CHX) revealed a mean strength of 14.52 ± 2.31 MPa. The use of 0.12% CHX mouth rinse, for one week before bonding, did not affect the shear bond strength of polycarbonate brackets bonded with Transbond composite. Furthermore, these brackets showed clinically acceptable bond strength.

  5. Deproteinization of tooth enamel surfaces to prevent white spot lesions and bracket bond failure: A revolution in orthodontic bonding

    OpenAIRE

    Roberto Justus

    2016-01-01

    Orthodontic treatment success is jeopardized by the risk of development of white spot lesions (WSLs) around orthodontic brackets. Unfortunately, the formation of WSLs still remains a common complication during treatment in patients with poor oral hygiene. Nearly 75% of orthodontic patients are reported to develop enamel decalcification because of prolonged plaque retention around brackets. It is the orthodontist′s responsibility to minimize the risk of patients having enamel decalcifications ...

  6. Effect of various commercially available mouthrinses on shear bond strength of orthodontic metal brackets: An in vitro study

    Directory of Open Access Journals (Sweden)

    Nazeer Ahmed Meeran

    2013-01-01

    Conclusion: Alcohol containing mouthrinses affect the shear bond strength of the metal orthodontic brackets bonded with composite resin (Transbond XT in the present study, more when compared with alcohol-free mouthrinses. It is, therefore, highly advisable to avoid alcohol containing mouthrinses in patients undergoing orthodontic treatment and use alcohol-free mouthrinses as adjuncts to regular oral hygiene procedures for maintaining good enamel integrity and periodontal health, without compromising the shear bond strength of the bonded metal brackets.

  7. Effects of silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets

    Directory of Open Access Journals (Sweden)

    Saadet Atsü

    2011-06-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of tribochemical silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets. MATERIAL AND METHODS: Twenty debonded metal and 20 debonded ceramic brackets were randomly assigned to receive one of the following surface treatments (n=10 for each group: (1 sandblasting (control; (2 tribochemical silica coating combined with silane. Brackets were rebonded to the enamel surface on the labial and lingual sides of premolars with a light-polymerized resin composite. All specimens were stored in distilled water for 1 week and then thermocycled (5,000 cycles between 5-55ºC. Shear bond strength values were measured using a universal testing machine. Student's t-test was used to compare the data (α=0.05. Failure mode was assessed using a stereomicroscope, and the treated and non-treated bracket surfaces were observed by scanning electron microscopy. RESULTS: Rebonded ceramic brackets treated with silica coating followed by silanization had significantly greater bond strength values (17.7±4.4 MPa than the sandblasting group (2.4±0.8 MPa, P<0.001. No significant difference was observed between the rebonded metal brackets treated with silica coating with silanization (15±3.9 MPa and the sandblasted brackets (13.6±3.9 MPa. Treated rebonded ceramic specimens primarily exhibited cohesive failure in resin and adhesive failure at the enamel-adhesive interface. CONCLUSIONS: In comparison to sandblasting, silica coating with aluminum trioxide particles followed by silanization resulted in higher bond strengths of rebonded ceramic brackets.

  8. The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel

    OpenAIRE

    Hooman Zarif Najafi; Vahid Moshkelgosha; Atefeh Khanchemehr; Akram Alizade; Ali Mokhtar

    2015-01-01

    Statement of the Problem: Some studies have reported the bond strength to be significantly lower in fluorotic enamels than the non-fluorosed. Purpose: The purpose of this study was to evaluate the shear bond strength of metallic brackets to non-fluorosed and fluorosed teeth after different enamel conditioning. Materials and Method: A total of 176 freshly extracted human premolars (88 non-fluorosed and 88 fluorosed teeth) were used in this study for bonding the metallic brackets. Teeth w...

  9. Effect of different concentrations of papain gel on orthodontic bracket bonding.

    Science.gov (United States)

    Pithon, Matheus M; Ferraz, Caio S; Oliveira, Gabriel D Couto; Dos Santos, Adrielle M

    2013-08-19

    The objective of this study was to verify the hypothesis that enamel deproteinization with papain gel at concentrations of 2%, 4%, 6%, 8%, and 10% increases shear bond strength as concentration increases. A total of 180 bovine mandibular permanent incisors were used, divided into six groups (n=30), and denominated as follows: group 1 is the control group (CG) in which brackets are bonded with resin-modified glass ionomer cement (RMGIC) according to the manufacturer's recommendations and groups 2, 3, 4, 5, and 6 have brackets bonded with RMGIC after enamel deproteinization with papain gel at concentrations of 2%, 4%, 6%, 8%, and 10%, respectively. After bonding, teeth were immersed in artificial saliva and kept at a temperature of 37°C for 24 h. Mechanical tests were then performed in a universal mechanical test machine EMIC DL 5000 (Sao Jose dos Pinhais, Brazil). Values obtained were submitted to analysis of variance and then to Tukey's test (p0.05). It was concluded that enamel deproteinization with 8% and 10% papain gel increases shear bond strength of orthodontic brackets bonded with RMGIC.

  10. Improving Tensile Bond Strength of Orthodontic Bracket by Applying Papain Gel as an Email Deproteinization Agent

    Directory of Open Access Journals (Sweden)

    Niswati Fathmah Rosyida

    2017-12-01

    Full Text Available An effort to improve the bonding between bracket and tooth surface is required. Objective: The aim of this studywas to evaluate the effect of papain gel on tensile bond strength (TBS and adhesive remnant index (ARI of the orthodontic brackets. Methods: A total of 42 healthy human premolars were randomly divided into six groups. 1 Resin-modifed glass ionomer cement (RMGIC without papain, 2 RMGIC with papain 8%, 3 RMGIC with papain 10%, 4 Composite resin (CR without papain, 5 CR with papain 8%, 6 CR with papain 10%. The TBS was determined using a universal testing machine. Bond failure was classifed according to the ARI. The TBS data were analyzed with Kruskal-Wallis test followed by Mean Whitney tests with 5% of signifcance level. Results: The mean of TBS(MPa values of RMGIC groups are without papain (5.03 ± 1.52, papain 8% (4.79 ± 2.61, papain 10 (7.75 ± 1, 48. CR groups without papain (5.45 ± 1.23, papain 8% (2.30 ± 0.73, and papain 10% (4.84 ± 1.72 Bond failure was mainly classifed as score 1. The TBS values were statistically influenced by the application of papain and adhesive. Conclusion: The application of papain 10% before RMGIC cementation improves the tensile bond strength and could decrease the bond failure of the orthodontic bracket.

  11. Nickel and chromium ion release from stainless steel bracket on immersion various types of mouthwashes

    Science.gov (United States)

    Mihardjanti, M.; Ismah, N.; Purwanegara, M. K.

    2017-08-01

    The stainless steel bracket is widely used in orthodontics because of its mechanical properties, strength, and good biocompatibility. However, under certain conditions, it can be susceptible to corrosion. Studies have reported that the release of nickel and chromium ions because of corrosion can cause allergic reactions in some individuals and are mutagenic. The condition of the oral environment can lead to corrosion, and one factor that can alter the oral environment is mouthwash. The aim of this study was to measure the nickel and chromium ions released from stainless steel brackets when immersed in mouthwash and aquadest. The objects consisted of four groups of 17 maxillary premolar brackets with .022 slots. Each group was immersed in a different mouthwash and aquadest and incubated at 37 °C for 30 days. After 30 days of immersion, the released ions were measured using the ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). For statistical analysis, both the Kruskal-Wallis and Mann-Whitney tests were used. The results showed differences among the four groups in the nickel ions released (p World Health Organization.

  12. Comparison of metal ion release from different bracket archwire combinations: an in vitro study.

    Science.gov (United States)

    Karnam, Srinivas Kumar; Reddy, A Naveen; Manjith, C M

    2012-05-01

    The metal ion released from the orthodontic appliance may cause allergic reactions particularly nickel and chromium ions. Hence, this study was undertaken to determine the amount of nickel, chromium, copper, cobalt and iron ions released from simulated orthodontic appliance made of new archwires and brackets. Sixty sets of new archwire, band material, brackets and ligature wires were prepared simulating fixed orthodontic appliance. These sets were divided into four groups of fifteen samples each. Group 1: Stainless steel rectangular archwires. Group 2: Rectangular NiTi archwires. Group 3: Rectangular copper NiTi archwires. Group 4: Rectangular elgiloy archwires. These appliances were immersed in 50 ml of artificial saliva solution and stored in polypropylene bottles in the incubator to simulate oral conditions. After 90 days the solution were tested for nickel, chromium, copper, cobalt and iron ions using atomic absorption spectrophotometer. Results showed that high levels of nickel ions were released from all four groups, compared to all other ions, followed by release of iron ion levels. There is no significant difference in the levels of all metal ions released in the different groups. The study confirms that the use of newer brackets and newer archwires confirms the negligible release of metal ions from the orthodontic appliance. The measurable amount of metals, released from orthodontic appliances in artificial saliva, was significantly below the average dietary intake and did not reach toxic concentrations.

  13. Stretched graphene tented by polycaprolactone and polypyrrole net–bracket for neurotransmitter detection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhenzhen; Ying, Ye; Li, Li; Xu, Ting; Wu, Yiping; Guo, Xiaoyu; Wang, Feng; Shen, Haojie; Wen, Ying, E-mail: ying.wen@shnu.edu.cn; Yang, Haifeng, E-mail: Hfyang@shnu.edu.cn

    2017-02-28

    Highlights: • A new DA sensor is constructed with RGO and electrospun polymer fiber film. • RGO sheets can be mechanically stretched by the as-fabricated net-brackets. • The DA sensor shows highly catalytic activity toward the oxidation of dopamine. • The as-prepared sensor is used to detect DA in injection or urine. • The protocol to make sensors in large scale way has good reproducibility. - Abstract: A net-bracket built out from the core@shell structure of chemically oxidized polypyrrole (PPy) coated electrospun polycaprolactone (PCL) nanofibers, and the following surface modification of a thin layer of positively charged poly(dimethyl diallyl ammonium chloride) (PDDA) has been applied for stretching the reduced graphene oxide (RGO) sheets to some extent with the electrochemical deposition method. The as-formed RGO/PDDA/PCL@PPy nanocomposites were investigated by using scanning electron microscopy, transmission electron microscope, X-ray diffraction and Raman spectroscopy. The graphene tented by the net-bracket showed remarkable electrocatalytic properties in detecting the neurotransmitter dopamine (DA). Low detection limit of 0.34 μM (S/N = 3) with the wide linear detection range from 4 μM to 690 μM was obtained. The successful determination of DA in real urine samples and DA injection were achieved. Such attractive fabrication strategy can be extended to make other graphene sheet-based sensors.

  14. Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation

    Science.gov (United States)

    Giacomo, Giovanni Di; Costantini, Alberto; de Gasperis, Nicola; De Vita, Andrea; Lin, Bernard K. H.; Francone, Marco; Beccaglia, Mario A. Rojas; Mastantuono, Marco

    2013-01-01

    Aims: One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis. Materials and Methods: A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques. Results: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P Latarjet procedure. Conclusion: Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings. Level of Evidence: Level 4. Clinical Relevance: Prospective case series, Treatment study. PMID:23858288

  15. Dentoalveolar mandibular changes with self-ligating versus conventional bracket systems: A CBCT and dental cast study

    Directory of Open Access Journals (Sweden)

    Marcio Rodrigues de Almeida

    2015-06-01

    Full Text Available OBJECTIVE: The aim of the present study was to compare dentoalveolar changes in mandibular arch, regarding transversal measures and buccal bone thickness, in patients undergoing the initial phase of orthodontic treatment with self-ligating or conventional bracket systems. METHODS: A sample of 25 patients requiring orthodontic treatment was assessed based on the bracket type. Group 1 comprised 13 patients bonded with 0.022-in self-ligating brackets (SLB. Group 2 included 12 patients bonded with 0.022-in conventional brackets (CLB. Cone-beam computed tomography (CBCT scans and a 3D program (Dolphin assessed changes in transversal width of buccal bone (TWBB and buccal bone thickness (BBT before (T1 and 7 months after treatment onset (T2. Measurements on dental casts were performed using a digital caliper. Differences between and within groups were analyzed by Student's t-test; Pearson correlation coefficient was also calculated. RESULTS: Significant mandibular expansion was observed for both groups; however, no significant differences were found between groups. There was significant decrease in mandibular buccal bone thickness and transversal width of buccal bone in both groups. There was no significant correlation between buccal bone thickness and dental arch expansion. CONCLUSIONS: There were no significant differences between self-ligating brackets and conventional brackets systems regarding mandibular arch expansion and changes in buccal bone thickness or transversal width of buccal bone.

  16. Effect of time and pH on physical-chemical properties of orthodontic brackets and wires.

    Science.gov (United States)

    Dos Santos, Aretha Aliny Ramos; Pithon, Matheus Melo; Carlo, Fabíola Galbiatti Carvalho; Carlo, Hugo Lemes; de Lima, Bruno Alessandro Silva Guedes; Dos Passos, Tibério Andrade; Lacerda-Santos, Rogério

    2015-03-01

    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. 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 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). 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.

  17. Alterations in plaque accumulation and gingival inflammation promoted by treatment with self-ligating and conventional orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Mauricio de Almeida Cardoso

    2015-04-01

    Full Text Available OBJECTIVE: The aim of the present study was to evaluate, comparatively, the periodontal response during orthodontic treatment performed with self-ligating and conventional brackets. METHODS: Sixteen Caucasian individuals of both sexes, aged between 12 and 16 years old and in permanent dentition were selected. Eight individuals were treated with conventional brackets installed on the lower dental arch and self-ligating brackets on the upper arch. Another eight individuals received self-ligating brackets in the lower arch and conventional brackets in the upper arch. The subjects received material and instructions for oral hygiene. Visible plaque index (VPI, gingival bleeding index (GBI and clinical attachment level (CAL were evaluated just after installation of orthodontic appliances, and 30, 60 and 180 days later. Mann-Whitney test was used to compare differences between groups (self-ligating and conventional, two-way ANOVA followed by Tukey's test was used to assess CAL at each site of each tooth. Significance level was set at 5%. RESULTS: No significant changes were found with regard to the assessed parameters (VPI, GBI and CAL in either one of the systems. CONCLUSION: No significant changes were found with regard to the periodontal response to orthodontic treatment for the variables assessed and between subjects receiving passive self-ligating and conventional brackets. All individuals had received oral hygiene instructions and had their periodontal conditions monitored.

  18. Standardizing operational vector sampling techniques for measuring malaria transmission intensity: evaluation of six mosquito collection methods in western Kenya.

    Science.gov (United States)

    Wong, Jacklyn; Bayoh, Nabie; Olang, George; Killeen, Gerry F; Hamel, Mary J; Vulule, John M; Gimnig, John E

    2013-04-30

    Operational vector sampling methods lack standardization, making quantitative comparisons of malaria transmission across different settings difficult. Human landing catch (HLC) is considered the research gold standard for measuring human-mosquito contact, but is unsuitable for large-scale sampling. This study assessed mosquito catch rates of CDC light trap (CDC-LT), Ifakara tent trap (ITT), window exit trap (WET), pot resting trap (PRT), and box resting trap (BRT) relative to HLC in western Kenya to 1) identify appropriate methods for operational sampling in this region, and 2) contribute to a larger, overarching project comparing standardized evaluations of vector trapping methods across multiple countries. Mosquitoes were collected from June to July 2009 in four districts: Rarieda, Kisumu West, Nyando, and Rachuonyo. In each district, all trapping methods were rotated 10 times through three houses in a 3 × 3 Latin Square design. Anophelines were identified by morphology and females classified as fed or non-fed. Anopheles gambiae s.l. were further identified as Anopheles gambiae s.s. or Anopheles arabiensis by PCR. Relative catch rates were estimated by negative binomial regression. When data were pooled across all four districts, catch rates (relative to HLC indoor) for An. gambiae s.l (95.6% An. arabiensis, 4.4% An. gambiae s.s) were high for HLC outdoor (RR = 1.01), CDC-LT (RR = 1.18), and ITT (RR = 1.39); moderate for WET (RR = 0.52) and PRT outdoor (RR = 0.32); and low for all remaining types of resting traps (PRT indoor, BRT indoor, and BRT outdoor; RR < 0.08 for all). For Anopheles funestus, relative catch rates were high for ITT (RR = 1.21); moderate for HLC outdoor (RR = 0.47), CDC-LT (RR = 0.69), and WET (RR = 0.49); and low for all resting traps (RR < 0.02 for all). At finer geographic scales, however, efficacy of each trap type varied from district to district. ITT, CDC-LT, and WET appear to be effective methods for large-scale vector sampling in

  19. Determination of Pu-238 Abundance in a Plutonium Standard by an Advanced Thermal Ionization Mass Spectrometric Technique

    Science.gov (United States)

    Mason, P.; Thomas, R.

    2006-12-01

    New developments in thermal ionization mass spectrometers allow for the determination of very small minor isotope ratios. The new hardware and software capabilities require attention to detail and accounting for additional sources of measurement uncertainty. The Pu-238 isotopic composition in New Brunswick Laboratory plutonium metal standard CRM 126-A was determined by thermal ionization mass spectrometry using combined Faraday cup and ion counting detection. A dynamic acquisition scheme was employed which provided for near real-time mass fractionation correction and ion counter/Faraday detector inter-calibration. Steps taken to minimize or eliminate isobaric U-238 interferences will be described, and an evaluation detailing contributions to the uncertainty, including SEM non-linearity, will be presented.

  20. A semi-automated technique determining the liver standardized uptake value reference for tumor delineation in FDG PET-CT.

    Directory of Open Access Journals (Sweden)

    Kenji Hirata

    Full Text Available 18F-fluorodeoxyglucose (FDG positron emission tomography (PET-computed tomography (CT has been an essential modality in oncology. We propose a semi-automated algorithm to objectively determine liver standardized uptake value (SUV, which is used as a threshold for tumor delineation.A large spherical volume of interest (VOI was placed manually to roughly enclose the right lobe (RL of the liver. For each voxel in this VOI, a coefficient of variation of voxel values (CVv was calculated for neighboring voxels within a radius of d/2. The voxel with the minimum CVv was then selected, where a 30-mm spherical VOI was placed at that voxel in accordance with PERCIST criteria. Two nuclear medicine physicians independently defined 30-mm VOIs manually on 124 studies in 62 patients to generate the standard values, against which the results from the new method were compared.The semi-automated method was successful in determining the liver SUV that was consistent between the two physicians in all the studies (d = 80 mm. The liver SUV threshold (mean +3 SD within 30-mm VOI determined by the new semi-automated method (3.12±0.61 was not statistically different from those determined by the manual method (Physician-1: 3.14±0.58, Physician-2: 3.15±0.58. The semi-automated method produced tumor volumes that were not statistically different from those by experts' manual operation. Furthermore, the volume change in the two sequential studies had no statistical difference between semi-automated and manual methods.Our semi-automated method could define the liver SUV robustly as the threshold value used for tumor volume measurements according to PERCIST. The method could avoid possible subjective bias of manual liver VOI placement and is thus expected to improve clinical performance of volume-based parameters for prediction of cancer treatment response.

  1. Minimal immunoreactive plasma beta-endorphin and decrease of cortisol at standard analgesia or different acupuncture techniques.

    Science.gov (United States)

    Harbach, H; Moll, B; Boedeker, R-H; Vigelius-Rauch, U; Otto, H; Muehling, J; Hempelmann, G; Markart, P

    2007-04-01

    Acupuncture has been claimed to be associated with activation of the endogenous antinociceptive system. The analgesic effects of acupuncture have been ascribed to beta-endorphin interacting with opioid receptors. However, firstly, the release of beta-endorphin into the blood has been proven to be induced by stress, i.e. under dysphoric conditions, and, secondly, if released under stress, beta-endorphin has been shown not to be analgesic. Our aim was to test whether beta-endorphin immunoreactive material is released into the cardiovascular compartment during acupuncture comparing the most frequently used types of acupuncture with standard pain treatment under apparently low stress conditions. This prospective study included 15 male patients suffering from chronic low back pain. beta-Endorphin immunoreactive material and cortisol were measured in the plasma of patients who underwent, in random order, therapy according to a standard pain treatment, traditional Chinese acupuncture, sham acupuncture, electro acupuncture and electro acupuncture at non-acupuncture points before, at and after the treatment. Statistical analysis was performed using two-way ANOVA with repeated measures. A decrease in plasma cortisol concentration measured over the five treatment protocols was highly significant (P < 0.001). The beta-endorphin immunoreactive material concentrations in plasma were minimal at all times and in all treatment conditions. The influence of treatments by various acupuncture procedures on cortisol and beta-endorphin immunoreactive material plasma concentrations over the three time points was not significantly different. beta-endorphin immunoreactive material in blood is not released by any type of acupuncture as tested under low stress conditions.

  2. Impact of Standardized Simulated Patients on First-Year Pharmacy Students' Knowledge Retention of Insulin Injection Technique and Counseling Skills.

    Science.gov (United States)

    Bowers, Riley; Tunney, Robert; Kelly, Kim; Mills, Beth; Trotta, Katie; Wheeless, C Neil; Drew, Richard

    2017-08-01

    Objective. To compare pre- and post-intervention test scores assessing insulin injection technique and counseling skills among P1 students with (intervention) or without (control) simulated patients, and to compare counseling checklist and knowledge retention test scores between groups. Methods. This study utilized cluster randomization. In addition to traditional instruction, the intervention group counseled a simulated patient on the use of insulin using the teach-back method. Test score changes from baseline were analyzed via two-sample t-test. Results. The intervention group exhibited a significantly greater increase in knowledge test scores from baseline compared to the control group. Similar changes were seen in post-instruction counseling checklist scores and knowledge retention test scores from baseline. Conclusion. Simulated patient interactions, when added to traditional coursework within a P1 skills lab, improve student counseling aptitude and knowledge retention scores.

  3. Layout techniques to enhance the radiation tolerance of standard CMOS technologies demonstrated on a pixel detector readout chip

    CERN Document Server

    Snoeys, W; Burns, M; Campbell, M; Cantatore, E; Carrer, N; Casagrande, L; Cavagnoli, A; Dachs, C; Di Liberto, S; Formenti, F; Giraldo, A; Heijne, Erik H M; Jarron, Pierre; Letheren, M F; Marchioro, A; Martinengo, P; Meddi, F; Mikulec, B; Morando, M; Morel, M; Noah, E; Paccagnella, A; Ropotar, I; Saladino, S; Sansen, Willy; Santopietro, F; Scarlassara, F; Segato, G F; Signe, P M; Soramel, F; Vannucci, Luigi; Vleugels, K

    2000-01-01

    A new pixel readout prototype has been developed at CERN for high- energy physics applications. This full mixed mode circuit has been implemented in a commercial 0.5 mu m CMOS technology. Its radiation tolerance has been enhanced by designing all NMOS transistors in enclosed geometry and introducing guardrings wherever necessary. The technique is explained and its effectiveness demonstrated on various irradiation measurements on individual transistors and on the prototype. Circuit performance started to degrade only after a total dose of 600 krad-1.7 Mrad depending on the type of radiation. 10 keV X-rays, /sup 60/Co gamma-rays, 6.5 MeV protons, and minimum ionizing particles were used. Implications of this layout approach on the circuit design and perspectives for even deeper submicron technologies are discussed. (20 refs).

  4. Use of the iTClamp versus standard suturing techniques for securing chest tubes: A randomized controlled cadaver study

    Directory of Open Access Journals (Sweden)

    Jessica Mckee

    2018-03-01

    Full Text Available Objectives: Tube thoracostomy (TT is a common yet potentially life-saving trauma procedure. After successful placement however, securing a TT through suturing is a skillset that requires practice, risking that the TT may become dislodged during prehospital transport. The purpose of this study was to examine if the iTClamp was a simpler technique with equivalent effectiveness for securing TTs. Materials and methods: In a cadaver model, a 1.5 inch incision was utilized along the upper border of the rib below the 5th intercostal space at the anterior axillary line. TTs (sizes 28Fr, 32Fr, 36Fr and 40Fr were inserted and secured with both suturing and iTClamp techniques according to the preset randomization. TT were then functionally tested for positive and negative pressure as well as the force required to remove the TT (pull test-up to 5 lbs. Time to secure the TT was also recorded. Results: When sutured is placed by a trained surgeon, the sutures and iTClamp were functionally equivalent for holding a positive and negative pressure. Mean pull force for both sutures and iTClamp exceeded the 5 lb threshold; there was no significant difference between the groups. Securing the TT with the iTClamp was significantly faster (p < 0.0001 with the iTClamp having a mean application time of 37.0 ± 22.8 s and using a suture had a man application time of 96.3 ± 29.0 s. Conclusion: The iTClamp was effective in securing TTs. The main benefit to the iTClamp is that minimal skill is required to adequately secure a TT to ensure that it does not become dislodged during transport to a trauma center. Keywords: Chest tube, Tube thoracostomy, Securing chest tubes

  5. Are flowable resin-based composites a reliable material for metal orthodontic bracket bonding?

    Science.gov (United States)

    Pick, Bárbara; Rosa, Vinícius; Azeredo, Tatiana Rocha; Cruz Filho, Eduardo Augusto Mascarenhas; Miranda, Walter Gomes

    2010-07-01

    To compare the tensile bond strength (TBS) and adhesive remnant index (ARI) of three flowable resin-based composites and three orthodontic adhesive systems for metal bracket bonding. Sixty bovine incisors were randomly divided into six groups. Enamel surfaces were etched with 37 percent phosphoric acid for 30 seconds and stainless steel orthodontic brackets were bonded using either flowable resin-based composites (3M Flow, FL; Tetric Flow, TF; and Wave, WA) or orthodontic bonding systems (Transbond XT, TX; Concise Orthodontic, CO; Fill Magic Ortodôntico, FM). All specimens were thermal cycled and stored in distilled water at 37°C for 24 hours, after which they were subsequently tested for TBS using a universal testing machine. ARI scores were determined after the failure of brackets. TBS and ARI data were submitted to ANOVA, Tukey, and Kruskal-Wallis tests (p=0.05), respectively. Rankings of the resin-based composites based on TBS means (MPa) were TX (6.4 ± 2.1), followed by CO (4.5 ± 2.7), FM (3.7 ± 1.2), FL (3.6 ± 1.2), TF (3.3 ± 1.2), and WA (2.4 ± 0.6). CO exhibited the lowest ARI mean score (0.9 ± 1.2) which was significantly different from the other five materials: TX (2.8 ± 0.42), FM (2.8 ± 0.42), FL (2.9 ± 0.32), TF (2.9 ± 0.32), and WA (3.0 ± 0.01). However, there were no statistically significant differences among the other groups with mean scores of 2.8-3.0. A score of 3.0 indicated that all the resin remained bonded to the tooth surface. The flowable resin-based composites tested (Fl, TF, and WA) used to bond metal orthodontic brackets to bovine enamel had low mean TBS values but acceptable ARI mean scores. Flowable composites may not be appropriate for bracket bonding, unless the teeth to be bonded are not subjected to higher orthodontic stresses, such as those without an antagonist.

  6. Salt Spray Test to Determine Galvanic Corrosion Levels of Electroless Nickel Connectors Mounted on an Aluminum Bracket

    Science.gov (United States)

    Rolin, T. D.; Hodge, R. E.; Torres, P. D.; Jones, D. D.; Laird, K. R.

    2014-01-01

    During preliminary vehicle design reviews, requests were made to change flight termination systems from an electroless nickel (EN) connector coating to a zinc-nickel (ZN) plating. The reason for these changes was due to a new NASA-STD-6012 corrosion requirement where connectors must meet the performance requirement of 168 hr of exposure to salt spray. The specification for class F connectors, MIL-DTL-38999, certifies the EN coating will meet a 48-hr salt spray test, whereas the ZN is certified to meet a 168-hr salt spray test. The ZN finish is a concern because Marshall Space Flight Center has no flight experience with ZN-finished connectors, and MSFC-STD-3012 indicates that zinc and zinc alloys should not be used. The purpose of this test was to run a 168-hr salt spray test to verify the electrical and mechanical integrity of the EN connectors and officially document the results. The salt spray test was conducted per ASTM B117 on several MIL-DTL-38999 flight-like connectors mounted to an aluminum 6061-T6 bracket that was alodined. The configuration, mounting techniques, electrical checks, and materials used were typical of flight and ground support equipment.

  7. Development, standardization and validation of purine excretion technique for measuring microbial protein supply for Yerli Kara cross-breed cattle

    International Nuclear Information System (INIS)

    Cetinkaya, N.; Ozdemir, H.; Gucus, A.I.; Ozcan, H.; Sogut, A.; Yaman, S.

    2002-01-01

    Three experiments were conducted to evaluate of the developed techniques for uric acid, allantoin and creatinine in Yerli Kara cross-breed cattle on farm at different feeding level locally available feed resources and linking the observed information to feed intake and to assess of protein nutrition status of Yerli Kara cross-breed dairy cattle using urinary PD and creatinine excretion. In Experiment I. Response of daily PD excretion to feed intake in Yerli Kara cross-breed on state farm was measured. Animals were fed a mixed diet containing 30 % wheat straw and 70 % compounded feed. The diet contained 90 % DM, its N and OM contents were 124 and 950 g/kg DM, respectively. In Experiment II. Spot urine sampling techniques was applied at state farm. Four Yerli Kara cross-breed bulls live weight with a mean of 211±41.3 kg were used. Experimental design, feeding and diet were the same as in Experiment I. The treatments were [located according to a 4x4 Latin Square design. In Experiment III. Spot urine sampling techniques was applied at smallholder farms. Compound feed containing 65 % barley, 25 % bran, 6 % sunflower seed meal, 3 % manner dust and 1 % mineral and vitamin mixture (120 g/kg DM-Crude Protein and 950 g/kg DM-Organic Matter)- was offered total in between 2 to 3 kg in two parts one in the morning (07:30 h) and one in the afternoon (17:00 h). Compound feed ingredients were similar given to all animals but Groups I, II and III animals were receiving 1 to 2 kg/d of straw (30 g CP/kg DM, 93Og OM/kg DM), grass hay (70g CP/kg DM, 915 g OM/kg DM), straw and grass hay respectively. There were significant correlations (R 2 =0.99) between PD excretion (mmol/d) and DOMI (kg/d) for YK-C cattle. PD execration (mmol/L) was plotted against PD: Creatinine W 0.75 to obtain slope and use as constant for the estimation of daily PD excretion from spot sampling from animals held by small holders. The equation could be expressed as: PD (mmol/d)=8.27+0.960 (PD:CxW 0.75 ). The

  8. Internal standardization--atomic spectrometry and geographical pattern recognition techniques for the multielement analysis and classification of Catalonian red wines.

    Science.gov (United States)

    Iglesias, Mònica; Besalú, Emili; Anticó, Enriqueta

    2007-01-24

    Major and minor (K, P, Ca, Mg, Na, Fe, Mn, Zn, and Sr) and trace (Ba, Ni, Pb, V, Co, Cd, and Sb) elements from wine samples from the Denomination of Origin (DO) Empordà-Costa Brava (Catalonia, Spain) were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) respectively. Previously, a comparison of different calibration methodologies and sample digestion treatments had been carried out using ANOVA statistical tool. The obtained results demonstrated that internal standardization provides reliable results with the advantage that no further manipulation of the sample is needed. A principal component analysis of the concentration data was performed to differentiate the samples of DO Empordà-Costa Brava from wine samples from other wine-producing regions in Spain (i.e., Penedès, Somontano, and Rioja). It was found that Sr and Ba contents discriminate the two DO groups. Moreover, a discriminant analysis function involving both variables distinguishes the two groups with a 100% classification rate. At the level of the leave-one-out cross-validation, all of the Empordà-Costa Brava samples were well classified, whereas the other DOs presented two borderline misclassifications.

  9. Standard Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading Technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method establishes a procedure to measure the susceptibility of steel to a time-delayed failure such as that caused by hydrogen. It does so by measuring the threshold for the onset of subcritical crack growth using standard fracture mechanics specimens, irregular-shaped specimens such as notched round bars, or actual product such as fasteners (2) (threaded or unthreaded) springs or components as identified in SAE J78, J81, and J1237. 1.2 This test method is used to evaluate quantitatively: 1.2.1 The relative susceptibility of steels of different composition or a steel with different heat treatments; 1.2.2 The effect of residual hydrogen in the steel as a result of processing, such as melting, thermal mechanical working, surface treatments, coatings, and electroplating; 1.2.3 The effect of hydrogen introduced into the steel caused by external environmental sources of hydrogen, such as fluids and cleaners maintenance chemicals, petrochemical products, and galvanic coupling in an aqueous enviro...

  10. Detection of active noise control on the standard motorcycle exhaust Supra X 125 D using PVC pipe technique form Y

    Science.gov (United States)

    Isranuri, I.; Alfisyahrin; Nasution, A. R.

    2018-02-01

    This detection aims to obtain noise reduction on the supra X 125D motorcycle exhaust by using the Active Noise Control Method. The technique is done using a Y-shaped PVC pipe to be bolted on the exhaust, which then branch Y PVC is placed loudspeaker with impermeable conditions. The function of this loudspeaker is as a secondary noise to counter the primary noise of the sound of exhaust motorcycle Supra X 125D. The sound generator in this study is the ISD 4004 module, which serves to generate noise to counter the source noise. How this ISD 4004 module works is by recording source noise then recording the source noise and then reversed the phase 180° by phase reversing circuit. So that, the noise generated by the sound generator will hit the source noise and encounter or such as addition of two different phase of sound will result in noise reduction when detected at the end of the Y-shaped PVC pipe. Inverted phase reversed using feed-back resistor 1 kΩ and 2 kΩ input resistors, 16V capacitor 2500μf and as amplifier using ICL 7660 and TL 702 CP. Test results on the highest 1000 rpm rotation engine speed on the Z axis of 2 dB, and at the highest 2000 rpm rotation engine speed also occurs on the Z axis of 1.5 dB.

  11. Evaluation of Image Processing Technique for Measuring of Nitrogen and Yield in Paddy Rice and Comparing it with Standard Methods

    Directory of Open Access Journals (Sweden)

    M.R Larijani

    2011-09-01

    Full Text Available In order to use new and low cost methods in precision agriculture, nitrogen should be supplied for plants on time and precisely. For determining the required nitrogen of paddy rice in the clustering stage, a series of experiments were conducted using three different methods of: image processing, kjeldahl and chlorophyll meter set (SPAD-502, in a randomized complete block design with three replications during 2010 at Rice Research Center of Tonekabon, Iran. Four experimental treatments were different level of fertilizer (Urea with 46% nitrogen. In the clustering stage, some images from rice plants were taken vertically by a digital camera and were analyzed using image processing technique. Simultaneously the chlorophyll index of plants was measured by SPAD-502 chlorophyll meter set and the percentage amount of nitrogen was measured using of the so called kjeldahl laboratory method. The results showed that the three methods of determining nitrogen of rice plant were highly correlated. Moreover, the correlation among the three methods and crop yield were almost the same. In general, the method of image processing could have a high potential for nitrogen management in the field, while this method was low-cost, faster and also nondestructive in comparison to the other methods.

  12. Scaffolds with a standardized macro-architecture fabricated from several calcium phosphate ceramics using an indirect rapid prototyping technique

    Science.gov (United States)

    Wilson, C. E.; van Blitterswijk, C. A.; Verbout, A. J.; de Bruijn, J. D.

    2010-01-01

    Calcium phosphate ceramics, commonly applied as bone graft substitutes, are a natural choice of scaffolding material for bone tissue engineering. Evidence shows that the chemical composition, macroporosity and microporosity of these ceramics influences their behavior as bone graft substitutes and bone tissue engineering scaffolds but little has been done to optimize these parameters. One method of optimization is to place focus on a particular parameter by normalizing the influence, as much as possible, of confounding parameters. This is difficult to accomplish with traditional fabrication techniques. In this study we describe a design based rapid prototyping method of manufacturing scaffolds with virtually identical macroporous architectures from different calcium phosphate ceramic compositions. Beta-tricalcium phosphate, hydroxyapatite (at two sintering temperatures) and biphasic calcium phosphate scaffolds were manufactured. The macro- and micro-architectures of the scaffolds were characterized as well as the influence of the manufacturing method on the chemistries of the calcium phosphate compositions. The structural characteristics of the resulting scaffolds were remarkably similar. The manufacturing process had little influence on the composition of the materials except for the consistent but small addition of, or increase in, a beta-tricalcium phosphate phase. Among other applications, scaffolds produced by the method described provide a means of examining the influence of different calcium phosphate compositions while confidently excluding the influence of the macroporous structure of the scaffolds. PMID:21069558

  13. [Western blot technique standardization of the diagnosis of human fasciolosis using Fasciola hepatica excreted-secreted antigens].

    Science.gov (United States)

    Escalante, Hermes; Davelois, Kelly; Ortiz, Pedro; Rodríguez, Hans; Díaz, Enrique; Jara, César

    2011-01-01

    To evaluate the performance of the enzyme-linked immunoelectrotransfer blot assay (EITB, Western blot) using excretory/secretory antigens from adult forms of Fasciola hepatica (Fh E/S Ag) for the diagnosis of human fasciolosis. Antigens were obtained after 18 hours of incubation in culture medium Minimum Essential Eagle, prepared at a protein concentration of 0.15 ug/uL and run against a pool of sera of patients with proven fasciolosis (confirmed by the finding of parasite eggs in the stool microscopy). Antigens of 10, 12, 17, 23, 27, 30, 36, 43, 66 and 136 kDa were detected and used to develop the Western blot technique. The sensitivity was evaluated using sera from 67 fasciolosis patients, and the specificity using sera from 57 patients with other parasitic diseases, and 10 from healthy individuals. Out of the 67 sera, 64 reacted with the 23 kDa band and 61 with the one of 17 kDa. These two bands were not detected in sera from patients with other parasitic diseases or in those from healthy volunteers and thus could be considered specific and diagnostic. The sensitivity of the test, using the bands of 17 and 23 kDa, was 95.5% for positive reactions to at least one of these two bands, being its specificity 100% with a positive predictive value of 100% and negative predictive value of 95.71%.

  14. Actual survey of dose evaluation method for standardization of radiation therapy techniques. With special reference to display method of radiation doses

    International Nuclear Information System (INIS)

    Kumagai, Kozo; Yoshiura, Takao; Izumi, Takashi; Araki, Fujio; Takada, Takuo; Jingu, Kenichi.

    1994-01-01

    This report presents the results of questionnaire survey for actual conditions of radiation therapy, which was conducted with the aim of establishing the standardization of radiation therapy techniques. Questionnaires were sent to 100 facilities in Japan, and 86 of these answered, consisting of 62 university hospitals, 2 national hospitals, 14 cancer centers, 4 prefectural or municipal hospitals, and 4 other hospitals. In addition to electron beam therapy, the following typical diseases for radiation therapy were selected as standard irradiation models: cancers of the larynx, esophagus, breast, and uterine cervix, and malignant lymphomas. According to these models, questionnaire results are analyzed in terms of the following four items: (1) irradiation procedures, (2) energy used for radiotherapy, (3) the depth for calculating target absorption doses, and (4) points for displaying target absorption doses. (N.K.)

  15. Salivary Fluoride level in preschool children after toothbrushing with standard and low fluoride content dentifrice, using the transversal dentifrice application technique: pilot study

    Directory of Open Access Journals (Sweden)

    Fabiana Jandre Melo

    2008-01-01

    Full Text Available Objective: To investigate the salivary fluoride concentration in pre-school children after toothbrushing with dentifrice containing standard (1100ppmF/NaF and low (500ppmF/NaF fluoride concentration, using the transversal technique of placing the product on the toothbrush. Methods: Eight children of both sexes, ranging from 4 to 9 years, and 5 years and 6 months of age, participated in the study. The experiment was divided into two phases with a weekly interval. In the first stage, the children used the standard concentration dentifrice for one week, and in the second, the low concentration product. Samples were collected at the end of each experimental stage, at the following times: Before brushing, immediately afterwards, and after 15, 30 and 45 minutes. The fluoride contents were analyzed by the microdiffusion technique. Statistical analysis was done by the analysis of variance ANOVA and Student’s-t test (p<0.05. Results: The salivary fluoride concentration was significantly higher at all times, when the standard concentration product was used. The comparison between the Halogen concentration found before bushing and immediately afterwards, showed that there was a 6.8 times increase in the standard dentifrice (0.19 x 1.29μgF/ml and in the low concentration product, an increase of 20.5 times (0.02 x 0.41μgF/ml. Conclusion: Toothbrushing with both products promoted relevant increases in the salivary fluoride concentration; however, longitudinal studies are necessary to verify the clinical result of this measurement.

  16. Precision of a photogrammetric method to perform 3D wound measurements compared to standard 2D photographic techniques in the horse.

    Science.gov (United States)

    Labens, R; Blikslager, A

    2013-01-01

    Methods of 3D wound imaging in man play an important role in monitoring of healing and determination of the prognosis. Standard photographic assessments in equine wound management consist of 2D analyses, which provide little quantitative information on the wound bed. 3D imaging of equine wounds is feasible using principles of stereophotogrammetry. 3D measurements differ significantly and are more precise than results with standard 2D assessments. Repeated specialised photographic imaging of 4 clinical wounds left to heal by second intention was performed. The intraoperator variability in measurements due to imaging and 3D processing was compared to that of a standard 2D technique using descriptive statistics and multivariate repeated measures ANOVA. Using a custom made imaging system, 3D analyses were successfully performed. Area and circumference measurements were significantly different between imaging modalities. The intraoperator variability of 3D measurements was up to 2.8 times less than that of 2D results. On average, the maximum discrepancy between repeated measurements was 5.8% of the mean for 3D and 17.3% of the mean for 2D assessments. The intraoperator repeatability of 3D wound measurements based on principles of stereophotogrammetry is significantly increased compared to that of a standard 2D photographic technique indicating it may be a useful diagnostic and monitoring tool. The equine granulation bed plays an important role in equine wound healing. When compared to 2D analyses 3D monitoring of the equine wound bed allows superior quantitative characterisation, contributing to clinical and experimental investigations by offering potential new parameters. © 2012 EVJ Ltd.

  17. Standardization of radiochemical techniques aiming the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region

    International Nuclear Information System (INIS)

    Guimaraes, Jean Remy Davee

    1992-09-01

    Methylation of inorganic Hg in aquatic systems is a key process in the environmental cycling of this metal, not yet studied in tropical conditions. Radiochemical techniques were adapted and simplified, aiming at the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region. Preliminary experiments showed, in 35 days volatilization of up to 32 % of 203 Hg 2+ added to aqueous solutions. Acid K 2 Cr 2 0 7 0.1 M solutions were not effective in 203 Hg 0 trapping and the latter was highly and irreversibly absorbed by a variety of synthetic materials commonly used in laboratory work. Considerably simplified versions of the Furutani and Rudd (1980) radiochemical technique for the determination of methylation rates in environmental samples were developed and showed efficiencies close to 90 % in tests with methyl- 2 0 3 H g standards. In-situ incubations of surface sediments were performed in the Madeira River gold mining region, Rondonia State, Brazil, and potential net Hg methylation rates (MR) of up to 1 %.g-1.h-1 were found in black-water affluent like the Mutum-Parana and Jamari rivers and in the Samuel reservoir. MRs in the Madeira River sediments were lower, ranging 10-5 to 10-3 %.g-1.h-1 . MRs obtained in incubations of samples some weeks after collection were one or two orders of magnitude lower than those resulting from in-situ incubations. Methylation in autoclaved samples was close to minimum detectable rates. MRs in surface water samples was in all cases < 7.10-7 %.ml-1.h-1. The determination of the predominant methylation sites will allow a better standardization of the technique described herein, suitable for MR determinations even under the unfavorable conditions prevailing in the Amazon region. (author)

  18. Desmistificando os braquetes autoligáveis Demystifying self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Renata Sathler

    2011-04-01

    Full Text Available Atualmente, os braquetes autoligáveis têm sido associados a tratamentos mais rápidos e eficazes, o que desperta a curiosidade em compará-los ao sistema convencional. Ao contrário dos braquetes tradicionais, os autoligáveis não necessitam de ligaduras, sejam elásticas ou metálicas. A literatura é farta em concluir que essa característica diminui, ostensivamente, a resistência do atrito durante as mecânicas de deslize. Além disso, existem alegações sobre a dimimuição da necessidade de extrações e de expansão maxilar com o uso desses acessórios. Portanto, o objetivo dessa revisão de literatura foi buscar os mais novos estudos a respeito dos aparelhos autoligáveis atualmente utilizados nos tratamentos ortodônticos, confirmando ou retificando as especulações vigentes.Currently self-ligating brackets have been associated to faster and more efficient treatments, which arouse the curiosity to compare them to the conventional system. Unlike traditional appliances, self-ligating brackets do not require elastomeric or metal ligatures. The literature is abundant in concluding that this feature decreases, ostensibly, the friction resistance during the sliding mechanics. Moreover, there are reports on minimizing the need of extractions and maxillary expansion using these accessories. Therefore, the purpose of this literature review was to seek the newest studies about the self-ligating brackets currently used in orthodontic treatments, confirming or correcting current speculations.

  19. Effectiveness of fluoride sealant in the prevention of carious lesions around orthodontic brackets: an OCT evaluation

    Directory of Open Access Journals (Sweden)

    Matheus Melo Pithon

    2015-12-01

    Full Text Available Abstract Objective: This article aimed to evaluate in vitro the efficiency of Pro Seal fluoride sealant application in the prevention of white spot lesions around orthodontic brackets. Material and Methods: Brackets were bonded to the buccal surface of bovine incisors, and five groups were formed (n = 15 according to the exposure of teeth to oral hygiene substances and the application of enamel sealant: G1 (control, only brushing was performed with 1.450 ppm fluoride; G2 (control brushing associated with the use of mouthwash with 225 ppm fluoride; G3, only Pro Seal sealant application was performed with 1.000 ppm fluoride; G4 Pro Seal associated with brushing; G5 Pro Seal associated with brushing and mouthwash. Experimental groups alternated between pH cycling and the procedures described. All specimens were kept at a temperature of 37 °C throughout the entire experiment. Both brushing and immersion in solutions were performed within a time interval of one minute, followed by washing in deionized water three times a day for 28 days. Afterwards, an evaluation by Optical Coherence Tomography (OCT of the spectral type was performed. In each group, a scanning exam of the white spot lesion area (around the sites where brackets were bonded and depth measurement of carious lesions were performed. Analysis of variance (ANOVA was applied to determine whether there were significant differences among groups. For post hoc analysis, Tukey test was used. Results: There was statistically significant difference between groups 1 and 2 (p = 0.003, 1 and 3 (p = 0.008, 1 and 4 (p = 0.000 and 1 and 5 (p = 0.000. The group in which only brushing was performed (Group 1 showed deeper enamel lesion. Conclusion: Pro Seal sealant alone or combined with brushing and/or brushing and the use of a mouthwash with fluoride was more effective in protecting enamel, in comparison to brushing alone.

  20. Tensile Bond Strength of Metal Bracket Bonding to Glazed Ceramic Surfaces With Different Surface Conditionings

    Directory of Open Access Journals (Sweden)

    M. Imani

    2011-12-01

    Full Text Available Objective: The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments.Materials and Methods: Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA. Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primerand adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively.Results: The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (P<0.01.Conclusion: In spite of limitations in laboratory studies it may be concluded that in application of Scotch bond multipurpose plus adhesive, phosphoric acid can be used instead of HFA for bonding brackets to the glazed ceramic restorations with enough tensile bond strength.

  1. Six-month bracket failure rate with a flowable composite: A split-mouth randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Sindhuja Krishnan

    Full Text Available ABSTRACT INTRODUCTION: The use of flowable composites as an orthodontic bonding adhesive merits great attention because of their adequate bond strength, ease of clinical handling and reduced number of steps in bonding. OBJECTIVE: The aim of this Randomized Controlled Trial was to comparatively evaluate over a 6-month period the bond failure rate of a flowable composite (Heliosit Orthodontic, Ivoclar Vivadent AG, Schaan and a conventional orthodontic bonding adhesive (Transbond XT, 3M Unitek. METHODS: 53 consecutive patients (23 males and 30 females who fulfilled the inclusion and exclusion criteria were included in the study. A total of 891 brackets were analyzed, where 444 brackets were bonded using Heliosit Orthodontic and 447 brackets were bonded using Transbond XT. The survival rates of brackets were estimated with the Kaplan-Meier analysis. Bracket survival distributions for bonding adhesives, tooth location and dental arch were compared with the log-rank test. RESULTS: The failure rates of the Transbond XT and the Heliosit Orthodontic groups were 8.1% and 6% respectively. No significant differences in the survival rates were observed between them (p= 0.242. There was no statistically significant difference in the bond failure rates when the clinical performance of the maxillary versus the mandibular arches and the anterior versus the posterior segments were compared. CONCLUSIONS: Both systems had clinically acceptable bond failure rates and are adequate for orthodontic bonding needs.

  2. Does self-ligating brackets type influence the hysteresis, activation and deactivation forces of superelastic NiTi archwires?

    Directory of Open Access Journals (Sweden)

    José Rino Neto

    2013-02-01

    Full Text Available OBJECTIVE: To compare hysteresis, activation and deactivation forces produced by first-order deformation of Contour 0.014-in NiTi wire (Aditek, Brazil in four brands of self-ligating brackets: Damon MX, Easy Clip, Smart Clip and In-Ovation. METHODS: Activation and deactivation forces were measured in an Instron universal tensile machine at 3 mm/minute speed to a total displacement of 4 mm. Tests were repeated eight times for each bracket/wire combination. Statistical analysis comprised ANOVA and Tukey's multiple comparisons test. RESULTS: Using a 4-mm deformation, mean activation forces increased in the following order: Damon = 222 gf, Easy Clip = 228 gf, In-Ovation = 240 gf and Smart Clip = 306 gf. The same order was observed for mean hysteresis values, i.e., 128 gf, 140 gf, 150 gf and 206 gf, respectively. The respective values of deactivation forces for the Damon, Easy Clip, In-Ovation and Smart Clip brackets were 94 gf, 88 gf, 90 gf and 100 gf. CONCLUSIONS: Brackets with higher activation forces were accompanied by higher hysteresis values, which resulted in clinically similar deactivation forces, regardless of the type of self-ligating brackets used.

  3. Comparison of mechanical properties of beta-titanium wires between leveled and unleveled brackets: an in vitro study.

    Science.gov (United States)

    Insabralde, Natalia Martins; Poletti, Thaís; Conti, Ana Cláudia; Oltramari-Navarro, Paula Vanessa; Lopes, Murilo B; Flores-Mir, Carlos; de Almeida, Marcio Rodrigues

    2014-05-30

    The objective of this study is to evaluate the force-deflection behavior of beta-titanium alloy wires between two leveled and unleveled bracket alignment scenarios using a three-point bending test. Six groups of ten beta-titanium alloy wire segments (0.017 × 0.025-in. diameter) of different manufacturers (Orthometric, Ortho Organizers, GAC, Morelli, and Ormco) were used. Both brackets were bonded to an acrylic jig with a 10-mm interbracket distance. A 1-mm deflection test in two hypothetical conditions (with aligned brackets and by simulating a 2-mm horizontal displacement of the brackets) was explored. Forces of activation and deactivation of the wires during both tests were compared by an analysis of variance (ANOVA) tests followed by a Tukey test. A statistically significant difference was found in the force-deflection behavior between some of the wires in both simulated in vitro conditions. For the leveled-type alignment scenario, the differences between wires were up to 70 g (range 110 to 179 g). For the unleveled-type alignment scenario, these differences were up to 65 g (range 111 to 175 g). The study showed some significant differences in forces generated during activation and deactivation among the five types of beta-titanium wires tested. In comparing leveled and unleveled brackets during activation, only Orthometric Beta Flexy and Ormco Beta-titanium were different between them.

  4. Biodegradação de braquetes ortodônticos: avaliação da liberação iônica in vitro Biodegradation of orthodontic brackets: in vitro ion release

    Directory of Open Access Journals (Sweden)

    Gabriel Schmidt Dolci

    2008-06-01

    Full Text Available OBJETIVO: avaliar, in vitro, a biodegradação de aparelhos ortodônticos simulados constituídos de braquetes e fios de aço inoxidável. METODOLOGIA: a amostra foi dividida em 2 grupos, de acordo com a marca dos braquetes usados: grupo A - Dyna-Lock, 3M/Unitek (AISI 303; e grupo B - LG Edgewise Standard, American Orthodontics (AISI 316L. Os corpos-de-prova permaneceram incubados em solução salina (0,05% a 36ºC, sob agitação por um período de até 60 dias. A análise da liberação iônica foi realizada por meio de espectrofotometria de absorção atômica. O peso em massa dos braquetes também foi medido antes e após o experimento. RESULTADOS: os resultados indicaram que o grupo A apresentou maior liberação de íons ferro, níquel e cromo do que o grupo B. Além disso, os braquetes do grupo A também mostraram perda de massa, considerada outro indicativo de corrosão. CONCLUSÃO: concluiu-se que, nas condições deste experimento, os braquetes do grupo A apresentaram maior biodegradação que os acessórios do grupo B, o que pode estar associado à liga metálica e/ou ao processo de fabricação dos mesmos.OBJECTIVE: The purpose of this study was to evaluate, in vitro, the biodegradation of simulated orthodontic appliances consisting of stainless steel brackets and wires. MATERIALS AND METHODOS: The sample was divided in 2 groups, according to brackets brand: group A - Dyna-Lock, 3M/ Unitek (AISI 303; and group B - LG Edgewise Standard, American Orthodontics (AISI 316L. The specimens (simulated orthodontic appliances were incubated in saline solution (0.05%, in shake, at 36ºC, for 60 days. The ion release was detected by atomic absorption spectrophotometer. The weight of brackets was also measured before and after the test. RESULTS: The results indicated that group A released more ions iron, nickel and chromium than group B. Moreover, the brackets in group A also presented weight loss, which is considered an indicator of corrosion

  5. Bowel sparing in pediatric cranio-spinal radiotherapy: a comparison of combined electron and photon and helical TomoTherapy techniques to a standard photon method

    International Nuclear Information System (INIS)

    Harron, Elizabeth; Lewis, Joanne

    2012-01-01

    The aim of this study was to compare the dose to organs at risk (OARs) from different craniospinal radiotherapy treatment approaches available at the Northern Centre for Cancer Care (NCCC), with a particular emphasis on sparing the bowel. Method: Treatment plans were produced for a pediatric medulloblastoma patient with inflammatory bowel disease using 3D conformal 6-MV photons (3DCP), combined 3D 6-MV photons and 18-MeV electrons (3DPE), and helical photon TomoTherapy (HT). The 3DPE plan was a modification of the standard 3DCP technique, using electrons to treat the spine inferior to the level of the diaphragm. The plans were compared in terms of the dose-volume data to OARs and the nontumor integral dose. Results: The 3DPE plan was found to give the lowest dose to the bowel and the lowest nontumor integral dose of the 3 techniques. However, the coverage of the spine planning target volume (PTV) was least homogeneous using this technique, with only 74.6% of the PTV covered by 95% of the prescribed dose. HT was able to achieve the best coverage of the PTVs (99.0% of the whole-brain PTV and 93.1% of the spine PTV received 95% of the prescribed dose), but delivered a significantly higher integral dose. HT was able to spare the heart, thyroid, and eyes better than the linac-based techniques, but other OARs received a higher dose. Conclusions: Use of electrons was the best method for reducing the dose to the bowel and the integral dose, at the expense of compromised spine PTV coverage. For some patients, HT may be a viable method of improving dose homogeneity and reducing selected OAR doses.

  6. A hybrid straightwire technique.

    Science.gov (United States)

    Celli, Daniel; Catalfamo, Lorenza; Gasperoni, Enrico; Deli, Roberto

    2017-09-01

    An original straightwire appliance was developed in order to easily adapt force and friction to the different stages and needs of treatment. The appliance features: (1) conventional brackets with a 0.020×0.030″ slot in the anterior area, passive self-ligating brackets with a 0.022×0.030″ slot in the lateral area, and tubes with a 0.022×0.030″ slot in the molar area; (2) archwires which adapt to the different stages of treatment and increase their section and stiffness progressively, starting with 0.014″ superelastic NiTi, passing through 0.016×0.025″ and 0.019×0.025″ heat-activated NiTi and reaching 0.019×0.025″ stainless steel working archwires; (3) use of several ligation systems which progressively increase their binding (low-friction ligatures, "O"- or "8"-shape elastomeric ligatures). Clinical cases are shown to illustrate the technique. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

  7. Evaluation of Effect of Air Abrasion on Friction and Surface Micromorphology of Passive Stainless Steel Self-Ligated Brackets: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Yasir Sate Mizhir

    2018-03-01

    Full Text Available The friction that occur between arch wire and the brackets during arch wire sliding in fixed orthodontic appliance will affect negatively on the outcome of the orthodontic treatment in addition to the treatment time. The process of friction is a critical issue and should be understood properly by the orthodontist in order to provide the optimum treatment result in a short period of time. Aim: The aim of our study was to compare the effect of calcium carbonate air abrasive on static friction and micromorphology of bracket slot surface for two different stainless steel self-ligated brackets. Methods: 120 passive stainless steel self-ligated brackets from two different commercial brands where involved in the study (discovery® sl2.0, Dentaurum co. and Damon®, Ormco co.. The samples were divided randomly into 8 groups, and every group with 5 samples, the criteria for classification of these groups depend on bracket types and air abrasion periods. Round (18 inches NITI arch wire was used to slide through 3 brackets with the middle one 1 mm higher than the others, the distance of sliding through the brackets was 10 mm, the machine used for measurement included the (instron universal testing machine, the roughness of the bracket slot surface was analyzed be the machine of (scanning electron microscope. Results: The effect of air abrasive agent calcium carbonate on the both types of metal self-ligated brackets result in elevation the amount of static friction for (discovery® l2.0 by 35.157%, Damon® by 36.652%. Viewing the slot of the brackets under microscope by using (SEM device reveal great modification in surface of the slot with uneven and rougher surface when compared to the brackets of control group that appear with polished and smooth surface.

  8. Influence of long-term in vivo exposure, debris accumulation and archwire material on friction force among different types of brackets and archwires couples.

    Science.gov (United States)

    Mezeg, Uroš; Primožic, Jasmina

    2017-11-30

    The aim was to assess the influence of long-term in vivo exposure, debris accumulation and archwire material on static and kinetic friction force among different types of brackets and archwires couples. Friction testing was performed among four lower incisors' brackets, conventional and self-ligating (SL), coupled with either nickel-titanium or stainless steel archwires, as-received and in vivo exposed in 18 subjects. The friction testing was performed for a sliding distance of 14 mm at a speed of 10 mm/min, with a starting force of 0.2 N. Wear and quantitative assessment of debris accumulation was performed on pictures of brackets obtained using a scanning electron microscope. Non parametric tests were used for statistical analysis. Only bracket type, but not exposure duration, amount of debris accumulation, archwire material or their manufacturer, was significantly correlated with both static (rho = 0.602, P friction force. Within each bracket type no significant difference was observed between as-received and in vivo exposed brackets for any friction parameter except for the SL brackets in which significantly higher static and kinetic (P = 0.001, at least) friction forces were seen in in vivo exposed SL brackets (164.9 cN and 217.63 cN, respectively) in comparison with as-received SL brackets (19.69 cN and 55.72 cN, respectively). The frictional testing was performed in the dry condition which might have influenced the results. A significant correlation was seen between friction force and bracket type, while treatment duration, amount of debris accumulation, archwire material or their manufacturer was not significantly correlated to it. Nevertheless, higher friction forces were measured among in vivo aged SL brackets in comparison with as-received ones. © The Author 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com

  9. Analysis of soil and sewage sludge by ICP-OES and the German standard DIN 38414 sample preparation technique (P3)

    International Nuclear Information System (INIS)

    Edlund, M.; Heitland, P.; Visser, H.

    2002-01-01

    Full text: The elemental analyses of soil and sewage sludge has developed to become one of the main applications for ICP optical emission spectrometry (ICP-OES) and is described in many official procedures. These methods include different acid mixtures and digestion techniques. Even though the German standard DIN 38414 part 7 and the Dutch NEN 6465 do not guarantee complete recoveries for all elements, they are widely accepted in Europe. This paper describes sample preparation, line selection and investigates precision, accuracy and Limits of detection. The SPECTRO CIROSCCD EOP with axial plasma observation and the SPECTRO CIROSCCD SOP with radial observation were compared and evaluated for the analyses of soil and sewage sludge. Accuracy was investigated using the certified reference materials CRM-141 R, CRM-143 R and GSD 11. Both instruments show excellent performance in terms of speed, precision, accuracy and detection limits for the determination of trace metals in soil and sewage sludge. (author)

  10. New overlay measurement technique with an i-line stepper using embedded standard field image alignment marks for wafer bonding applications

    Science.gov (United States)

    Kulse, P.; Sasai, K.; Schulz, K.; Wietstruck, M.

    2017-06-01

    In the last decades the semiconductor technology has been driven by Moore's law leading to high performance CMOS technologies with feature sizes of less than 10 nm [1]. It has been pointed out that not only scaling but also the integration of novel components and technology modules into CMOS/BiCMOS technologies is becoming more attractive to realize smart and miniaturized systems [2]. Driven by new applications in the area of communication, health and automation, new components and technology modules such as BiCMOS embedded RF-MEMS, high-Q passives, Sibased microfluidics and InP-SiGe BiCMOS heterointegration have been demonstrated [3-6]. In contrast to standard VLSI processes fabricated on front side of the silicon wafer, these new technology modules require addition backside processing of the wafer; thus an accurate alignment between the front and backside of the wafer is mandatory. In previous work an advanced back to front side alignment technique and implementation into IHP's 0.25/0.13 μm high performance SiGe:C BiCMOS backside process module has been presented [7]. The developed technique enables a high resolution and accurate lithography on the backside of BiCMOS wafer for additional backside processing. In addition to the aforementioned back side process technologies, new applications like Through-Silicon Vias (TSV) for interposers and advanced substrate technologies for 3D heterogeneous integration demand not only single wafer fabrication but also processing of wafer stacks provided by temporary and permanent wafer bonding [8]. Therefore, the available overlay measurement techniques are not suitable if overlay and alignment marks are realized at the bonding interface of a wafer stack which consists of both a silicon device and a silicon carrier wafer. The former used EVG 40NT automated overlay measurement system, which use two opposite positioned microscopes inspecting simultaneous the wafer back and front side, is not capable measuring embedded overlay

  11. Reliability evaluation of high-performance, low-power FinFET standard cells based on mixed RBB/FBB technique

    Science.gov (United States)

    Wang, Tian; Cui, Xiaoxin; Ni, Yewen; Liao, Kai; Liao, Nan; Yu, Dunshan; Cui, Xiaole

    2017-04-01

    With shrinking transistor feature size, the fin-type field-effect transistor (FinFET) has become the most promising option in low-power circuit design due to its superior capability to suppress leakage. To support the VLSI digital system flow based on logic synthesis, we have designed an optimized high-performance low-power FinFET standard cell library based on employing the mixed FBB/RBB technique in the existing stacked structure of each cell. This paper presents the reliability evaluation of the optimized cells under process and operating environment variations based on Monte Carlo analysis. The variations are modelled with Gaussian distribution of the device parameters and 10000 sweeps are conducted in the simulation to obtain the statistical properties of the worst-case delay and input-dependent leakage for each cell. For comparison, a set of non-optimal cells that adopt the same topology without employing the mixed biasing technique is also generated. Experimental results show that the optimized cells achieve standard deviation reduction of 39.1% and 30.7% at most in worst-case delay and input-dependent leakage respectively while the normalized deviation shrinking in worst-case delay and input-dependent leakage can be up to 98.37% and 24.13%, respectively, which demonstrates that our optimized cells are less sensitive to variability and exhibit more reliability. Project supported by the National Natural Science Foundation of China (No. 61306040), the State Key Development Program for Basic Research of China (No. 2015CB057201), the Beijing Natural Science Foundation (No. 4152020), and Natural Science Foundation of Guangdong Province, China (No. 2015A030313147).

  12. Assessment of pain experience in adults and children after bracket bonding and initial archwire insertion

    Directory of Open Access Journals (Sweden)

    Marcio José da Silva Campos

    2013-10-01

    Full Text Available INTRODUCTION: Ninety five percent of orthodontic patients routinely report pain, due to alterations in the periodontal ligament and surrounding soft tissues, with intensity and prevalence varying according to age. OBJECTIVE: This study aimed to assess toothache and buccal mucosal pain in adults and children during two initial phases of the orthodontic treatment. METHODS: The intensity of toothache and buccal mucosal pain reported by 20 patients, 10 children (11-13 years and 10 adults (18-37 years was recorded with the aid of a Visual Analog Scale (VAS, during 14 days - 7 days with bonded brackets only and 7 days with the initial archwire inserted. RESULTS: There was no significant difference in pain intensity among adults and children. After bracket bonding, 50% of the children and 70% of the adults reported pain. 70% of both groups reported pain after initial archwire insertion. While adults reported constant, low intensity, buccal mucosal pain, the children showed great variation of pain intensity, but with a trend towards decreasing pain during the assessment period. After initial archwire insertion the peaks of toothache intensity and prevalence occurred 24 hours in children and 48 hours in adults. CONCLUSIONS: In general, children reported pain less frequently than adults did, though with greater intensity.

  13. Should the orthodontic brackets always be removed prior to magnetic resonance imaging (MRI)?

    Science.gov (United States)

    Poorsattar-Bejeh Mir, Arash; Rahmati-Kamel, Manouchehr

    2016-01-01

    Request for temporary removal of orthodontic appliances due to medical conditions that require magnetic resonance (MR) imaging is not uncommon in daily practice in the field of orthodontics. This may be at the expense of time and cost. Metal Orthodontic appliances cause more signal loss and image distortion as compared to ceramic and titanium ones. Stainless steel and large brackets in addition to the oriented miniscrews in relation to the axis of magnetic field may cause severe signal loss and image distortion. Moreover, gradient echo and frequency-selective fat saturation MR protocols are more susceptible to metal artifacts. The spin echo and fat-suppression protocols, low magnetic field strength (e.g., 1.5 Tesla vs. 3 Tesla), small field of view, high-resolution matrix, thin slice, increased echo train length and increased receiver band width could be applied to lessen the metal artifacts in MR images. The larger the distance between an appliance and desired location to be imaged, the lower the distortion and signal loss. Decision to remove brackets should be made based on its composition and desired anatomic location. In this review, first the principles of MR imaging are introduced (Part-I) and then the interactions of orthodontic appliances and magnetic field are farther discussed (Part-II).

  14. Tensile bond strength of metal bracket bonding to glazed ceramic surfaces with different surface conditionings.

    Science.gov (United States)

    Akhoundi, Ms Ahmad; Kamel, M Rahmati; Hashemi, Sh Mahmood; Imani, M

    2011-01-01

    The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments. Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primer and adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively. The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (Ptensile bond strength.

  15. Effects of surface treatment of provisional crowns on the shear bond strength of brackets.

    Science.gov (United States)

    de Almeida, Josiane Xavier; Deprá, Mauren Bitencourt; Marquezan, Mariana; Retamoso, Luciana Borges; Tanaka, Orlando

    2013-01-01

    To assess the adhesive resistance of metallic brackets bonded to temporary crowns made of acrylic resin after different surface treatments. 180 specimens were made of Duralay and randomly divided into 6 groups (n = 30) according to surface treatment and bonding material: G1 - surface roughening with Soflex and bonding with Duralay; G2 - roughening with aluminum oxide blasting and bonding with Duralay; G3 - application of monomer and bonding with Duralay; G4 - roughening with Soflex and bonding with Transbond XT; G5 - roughening with aluminum oxide blasting and bonding with Transbond XT and G6 - application of monomer and bonding with Transbond. The results were statistically assessed by ANOVA/Games-Howell. The means (MPa) were: G1= 18.04, G2= 22.64, G3= 22.4, G4= 9.71, G5= 11.23, G6= 9.67. The Adhesive Remnant Index (ARI) ranged between 2 and 3 on G1, G2 and G3 whereas in G4, G5 and G6 it ranged from 0 to 1, showing that only the material affects the pattern of adhesive flaw. The surface treatment and the material influenced adhesive resistance of brackets bonded to temporary crowns. Roughening by aluminum blasting increased bond strength when compared to Soflex, in the group bonded with Duralay. The bond strength of Duralay acrylic resin was superior to that of Transbond XT composite resin.

  16. Should the orthodontic brackets always be removed prior to magnetic resonance imaging (MRI)?

    Science.gov (United States)

    Poorsattar-Bejeh Mir, Arash; Rahmati-Kamel, Manouchehr

    2015-01-01

    Request for temporary removal of orthodontic appliances due to medical conditions that require magnetic resonance (MR) imaging is not uncommon in daily practice in the field of orthodontics. This may be at the expense of time and cost. Metal Orthodontic appliances cause more signal loss and image distortion as compared to ceramic and titanium ones. Stainless steel and large brackets in addition to the oriented miniscrews in relation to the axis of magnetic field may cause severe signal loss and image distortion. Moreover, gradient echo and frequency-selective fat saturation MR protocols are more susceptible to metal artifacts. The spin echo and fat-suppression protocols, low magnetic field strength (e.g., 1.5 Tesla vs. 3 Tesla), small field of view, high-resolution matrix, thin slice, increased echo train length and increased receiver band width could be applied to lessen the metal artifacts in MR images. The larger the distance between an appliance and desired location to be imaged, the lower the distortion and signal loss. Decision to remove brackets should be made based on its composition and desired anatomic location. In this review, first the principles of MR imaging are introduced (Part-I) and then the interactions of orthodontic appliances and magnetic field are farther discussed (Part-II). PMID:27195213

  17. Effects of surface treatment of provisional crowns on the shear bond strength of brackets

    Directory of Open Access Journals (Sweden)

    Josiane Xavier de Almeida

    2013-08-01

    Full Text Available OBJECTIVE: To assess the adhesive resistance of metallic brackets bonded to temporary crowns made of acrylic resin after different surface treatments. METHODS: 180 specimens were made of Duralay and randomly divided into 6 groups (n = 30 according to surface treatment and bonding material: G1 - surface roughening with Soflex and bonding with Duralay; G2 - roughening with aluminum oxide blasting and bonding with Duralay; G3 - application of monomer and bonding with Duralay; G4 - roughening with Soflex and bonding with Transbond XT; G5 - roughening with aluminum oxide blasting and bonding with Transbond XT and G6: application of monomer and bonding with Transbond. The results were statistically assessed by ANOVA/Games-Howell. RESULTS: The means (MPa were: G1= 18.04, G2= 22.64, G3= 22.4, G4= 9.71, G5= 11.23, G6= 9.67. The Adhesive Remnant Index (ARI ranged between 2 and 3 on G1, G2 and G3 whereas in G4, G5 and G6 it ranged from 0 to 1, showing that only the material affects the pattern of adhesive flaw. CONCLUSION: The surface treatment and the material influenced adhesive resistance of brackets bonded to temporary crowns. Roughening by aluminum blasting increased bond strength when compared to Soflex, in the group bonded with Duralay. The bond strength of Duralay acrylic resin was superior to that of Transbond XT composite resin.

  18. Comparative study of friction between metallic and conventional interactive self-ligating brackets in different alignment conditions

    Directory of Open Access Journals (Sweden)

    Sérgio Ricardo Jakob

    2014-06-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the friction between three bracket models: conventional stainless steel (Ovation, Dentsply GAC, self-ligating ceramic (In-Ovation, Denstply GAC and self-ligating stainless steel brackets (In-Ovation R, Dentsply GAC. METHODS: Five brackets were used for each model. They were bonded to an aluminum prototype that allowed the simulation of four misalignment situations (n = 10. Three of these situations occurred at the initial phase (in which a 0.016-in nickel-titanium wire was used: 1. horizontal; 2. vertical; and 3. simultaneous horizontal/vertical. One of the situations occurred at the final treatment phase: 4. no misalignment (in which a 0.019 x 0.025-inch stainless steel rectangular wire was used. The wires slipped through the brackets and friction was measured by a Universal Testing Machine. RESULTS: Analysis of variance followed by Tukey's Test for multiple comparisons (α = 0.05 were applied to assess the results. Significant interaction (p < 0.01 among groups was found. For the tests that simulated initial alignment, Ovation(r bracket produced the highest friction. The two self-ligating models resulted in lower and similar values, except for the horizontal situation, in which In-Ovation C(r showed lower friction, which was similar to the In-Ovation R(r metallic model. For the no misalignment situation, the same results were observed. CONCLUSION: The self-ligating system was superior to the conventional one due to producing less friction. With regard to the material used for manufacturing the brackets, the In-Ovation C(r ceramic model showed less friction than the metallic ones.

  19. MEDICION IN VITRO DE LA FUERZA DE FRICCIÓN EN DUPLAS ARCO-BRACKET CON ANGULACIÓN

    OpenAIRE

    Murillo Mora, Emmanuel

    2012-01-01

    En ortodoncia se utilizan técnicas que buscan un máximo control sobre el movimiento de los dientes. Uno de los múltiples factores a considerar en la selección del material, es optar uno que genere menor fuerza friccional.(23). La reducción de la fricción es una de las metas para la nueva generación de bracket. Se investigó la fuerza friccional de 3 tipos de bracket de diferentes marcas comerciales siendo uno de autoligado (Smart Clip) y los otros con eslastomero, en este cas...

  20. Suction/inspiration against resistance or standardized Mueller maneuver: a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

    International Nuclear Information System (INIS)

    Gutzeit, Andreas; Froehlich, Johannes M.; Weymarn, Constantin von; Goyen, Matthias; Waelti, Stephan; Roos, Justus E.; Meissnitzer, Matthias; Hergan, Klaus; Czell, David; Reischauer, Carolin

    2015-01-01

    Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. (orig.)

  1. Suction/inspiration against resistance or standardized Mueller maneuver: a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

    Energy Technology Data Exchange (ETDEWEB)

    Gutzeit, Andreas [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland); Kantonsspital Winterthur, Department of Radiology, Winterthur (Switzerland); Froehlich, Johannes M.; Weymarn, Constantin von; Goyen, Matthias [Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Department of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Roos, Justus E. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Meissnitzer, Matthias; Hergan, Klaus [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Czell, David [Cantonal Hospital Winterthur, Department of Neurology, Winterthur (Switzerland); Reischauer, Carolin [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland)

    2015-11-15

    Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. (orig.)

  2. Expression of human immunodeficiency virus (HIV) in naturally infected peripheral blood mononuclear cells: comparison of a standard co-culture technique with a newly developed microculture method.

    Science.gov (United States)

    Eberlein, B; Baur, A; Neundorfer, M; Jahn, G

    1991-05-01

    Peripheral blood mononuclear cells (PBMCs) from 29 patients infected with human immunodeficiency virus (HIV) were cultured by two different methods. One was the standard co-culture technique, the other a newly developed microculture method. In this assay 10(6) PBMCs were cultivated in 250 microliters medium, no activating agents or allogeneic cells were present. P24 antigen production measured by this method was found in 7 out of 11 PBMC cultures of patients in the Walter Reed (WR) stage 1 or 2, whereas only 4 samples were positive by the co-culture procedure. Cultures from patients in the later stages of the disease (WR 5/6) showed a higher p24 production by the co-culture method than by the microculture assay. It is assumed that rapidly growing HIV strains can be better assessed by the co-culture method which may select for these strains. P24 expression can be more easily obtained by the microculture technique even in cases where slowly replicating strains may be present. In conclusion, results from the microculture procedure described may be a useful supplementation to findings observed by the co-culture method.

  3. The comparison of frictional resistance in titanium, self-ligating stainless steel, and stainless steel brackets using stainless steel and TMA archwires: An in vitro study

    Directory of Open Access Journals (Sweden)

    Syed Altaf Khalid

    2012-01-01

    Full Text Available Aim: The aim of the study was to compare the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and titanium molybdenum alloy (TMA archwires. Materials and Methods: We compared the frictional resistance in 0.018 slot and 0.022 slot of the three brackets - titanium, self-ligating stainless steel, and conventional stainless steel - using stainless steel archwires and TMA archwires. An in vitro study of simulated canine retraction was undertaken to evaluate the difference in frictional resistance between titanium, self-ligating stainless steel, and stainless steel brackets, using stainless steel and TMA archwires. Results and Conclusion: We compared the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and TMA archwires, with the help of Instron Universal Testing Machine. One-way analysis of variance (ANOVA, Student′s "t" test, and post hoc multiple range test at level of <0.05 showed statistically significant difference in the mean values of all groups. Results demonstrated that the titanium, self-ligating stainless steel, and stainless steel brackets of 0.018-inch and 0.022-inch slot had no significant variations in frictional résistance. The self-ligating bracket with TMA archwires showed relatively less frictional resistance compared with the other groups. The titanium bracket