K3 ENDO, PRO TAPER, AND PRO FILE SYSTEMS: BREAKAGE AND DISTORTION IN SEVERELY CURVED ROOTS OF MOLARS.By Matthew T. Ankrum, D.D.S.A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Gary R. Hartwell, D.D.S., M.S.Chairman and Professor, Department of EndodonticsIt was the aim of this study to investigate the incidence of file breakage and distortion when the Pro Taper, K3 Endo and ProFile systems were used to instrument canals in the severely curved roots of extracted molars.Forty-five roots of extracted mandibular and maxillary molars with curvatures between 40 and 75 degrees were chosen for use in this study. The roots in Group One were instrumented with the Pro File (PF) system and served as the control group. Roots in Group Two were instrumented with the Pro Taper (PT) system and those in Group Three were instrumented with the K3 Endo (K3) system. The three systems were used according to the manufacturers' instructions.The proportion of files distorted was 15.3% for the PF group, 2.4% for the PT group, and 8.3% for the K3 group. There was a statistically significant difference between the PF and PT groups (p = .0079). The percentage of broken files was 1.7% for the PF group, 6.0% for the PT group and 2.1% for the K3 group. No statistically significant differences were found between these three groups (p = .4243). The results of this study showed that these three rotary tapered systems were not significantly different with regard to breakage. There were significantly more distorted files in the PF group when compared to the PT group, with regard to distortion there was no significant difference between the PT and K3 and the PF and K3 groups.

Automobile and aero industries have an increasing interestin materials with improved mechanical properties. However, manyof these new materials are classified as difficult-to-cut withconventional tools. It is obvious that tools, cutting processesand cutting models has to be devel-oped parallel to materialsscience. In this thesis rotary cutting tools are tested as analternative toexpensive diamond or cubic bore nitridetools. Metal matrix composites mostly consist of a light metalalloy (such as aluminium or titanium) reinforced with hard andabrasive ceramic parti-cles or fibres. On machining, thereinforcement results in a high rate of tool wear. This is themain problem for the machining of MMCs. Many factors affect thelife length of a tool, i.e. matrix alloy, type, size andfraction of the reinforcement, heat treatment, cuttingconditions and tool properties. In tests, the Al-SiC MMC formed a deformation layer duringmilling, probably affected by lack of cooling. The dominatingfactor for tool life was the cutting speed. Water jet or CO2cooling of turning did not provide dramatic increase in toollife. With PCD, cutting speeds up to 2000 m/min were usedwithout machining problems and BUE formation. Tool flank wearwas abrasive and crater wear created an "orange-peel type" wearsurface. PCD inserts did not show the typical increase in flankwear rate at the end of its lifetime. The use of self-propelled rotary tools seems to be apromising way to increase tool life. No BUE was formed on therotary tool at high cutting data. The measurements indicatethat the rotary tool creates twice as good surface as PCDtools. The longest tool life was gained with an inclinationangle of 10 degrees. Tool costs per component will beapproximately the same, but rotary cutting tool allows higherfeeds and therefore a higher production rate and thus a lowerproduction cost. The rotary cutting operation might have a potential toincrease productiv-ity in bar peeling. The lack of BUE withrotary cutting gives hope on higher tool life. The test resultsshow that tool wear was 27% lower with rotary cutting tools.Increase of cutting speed from 22 to 44 m/min did not affectcutting forces. This indicates that the cutting speed canincrease without significant change in tool wear rate. Issues related to rotary cutting like cutting models,cutting processes, standards, tools and models have beendiscussed. A tool wear model with kinetic energy has beendiscussed. KEYWORDS:Difficult-to-Cut material, Metal MatrixComposite (MMC), Machining, Machinability, Rotary Cutting Tool,Acoustic Emission / <p>QCR 20161026</p>

Dispersed particle flows are encountered in many biological, geophysical but also in industrial situations, e.g. during processing of materials. In these flows, the particles usually are non-spherical and their angular dynamics play a crucial role for the final material properties. Generally, the angular dynamics of a particle is dependent on the local flow in the frame-of-reference of this particle. In this frame, the surrounding flow can be linearized and the linear velocity gradient will determine how the particle rotates. In this thesis, the main objective is to improve the fundamental knowledge of the angular dynamics of non-spherical particles related to two specific biobased material processes. Firstly, the flow of suspended cellulose fibers in a papermaking process is used as a motivation. In this process, strong shear rates close to walls and the size of the fibers motivates the study of inertial effects on a single particle in a simple shear flow. Through direct numerical simulations combined with a global stability analysis, this flow problem is approached and all stable rotational states are found for spheroidal particles with aspect ratios ranging from moderately slender fibers to thin disc-shaped particles. The second material process of interest is the production of strong cellulose filaments produced through hydrodynamic alignment and assembly of cellulose nanofibrils (CNF). The flow in the preparation process and the small size of the particles motivates the study of alignment and rotary diffusion of CNF in a strain flow. However, since the particles are smaller than the wavelength of visible light, the dynamics of CNF is not easily captured with standard optical techniques. With a new flow-stop experiment, rotary diffusion of CNF is measured using Polarized optical microscopy. This process is found to be quite complicated, where short-range interactions between fibrils seem to play an important role. New time-resolved X-ray characterization techniques were used to target the underlying mechanisms, but are found to be limited by the strong degradation of CNF due to the radiation. Although the results in this thesis have limited direct applicability, they provide important fundamental stepping stones towards the possibility to control fiber orientation in flows and can potentially lead to new tailor-made materials assembled from a nano-scale. / <p>QC 20160929</p>

<div>Vapor compression cycles are the most common method used to provide cooling to environments. In the residential area, refrigerator/freezers as well as air conditioners/heat pumps almost exclusively use vapor compression cycles. The driving force behind a vapor compression cycle is the compressor, where a variety of compressor types are used in the same application. While reciprocating compressors are found in the majority of refrigerator/freezers, scroll compressors are predominantly used in residential air conditioners. Yet other compressors have emerged as replacements due to increased efficiency. A R134a oil-free prototype scroll compressor and a R134a reciprocating compressor are operated in a hot-gas bypass test stand under refrigerator/freezer conditions to compare performance. Additionally, a R407C scroll compressor and a R410A rotary compressor are operated in a compressor calorimeter under air conditioning/heat pump conditions to compare performance. Experimental results show that the reciprocating compressor far outperforms the prototype scroll compressor in the refrigerator/freezer application, while the performance between the scroll and rotary compressors are almost equal in the air conditioning application.</div><div>Pressure fluctuation at compressor discharge is also measured in the compressor calorimeter to determine feasibility of applying a novel muffling design to air conditioning compressors, although it was found that traditional muffling methods currently used are effective to a degree such that this new method is unwarranted. Data from the compressor calorimeter is also used to investigate the accuracy of the AHRI 540 10-Coefficient Correlation compressor map in predicting performance both inside and outside the tested operating conditions. The AHRI 10-Coefficient Correlation achieves high accuracy inside tested operating conditions but is inept in extrapolating performance, where other map correlations are more accurate.</div>

O presente estudo teve como objetivo avaliar, por meio da microscopia eletrônica de varredura (M.E.V.), a remoção de detritos e deformação superficial sofrida pelos sistemas endodônticos rotatórios de NiTi BioRace (BR); Protaper (PT) e Twisted File (TF) após cada uso, totalizando cinco usos, simulando as condições clínicas. Um total de 75 molares superiores humanos extraídos cuja raiz disto-vestibular apresentava curvatura de 0 a 5° e mésio-vestibular entre 20 e 30° de acordo com o método de Weine, foram selecionados e divididos em três grupos com 25 espécimes. Para o grupo I: realizou-se instrumentação com o sistema BR; para o grupo II com o sistema PT e para o grupo III, com o TF. Foram utilizadas cinco caixas de cada sistema rotatório para instrumentar os canais mesio e distovestibulares. Inicialmente os instrumentos foram fotografados em M.E.V. com aumento de 35 vezes, utilizados uma vez e em seguida passaram por um protocolo de limpeza baseado no proposto por Parashos, Linsuwanont e Messer (2004) previamente a esterilização e, em seguida eram analisados em M.E.V., antes do uso seguinte. Esses procedimentos foram realizados até o último uso. Os dados de limpeza foram submetidos ao teste estatístico de Kruskal Wallis para comparação global e ao teste de Dunn para comparação individual dos grupos, enquanto para análise da deformação foram submetidos ao teste estatístico do Qui-quadrado para comparação global e ao teste exato de Fisher para as comparações individuais, todos com significância de 5%. Os resultados apontaram diferenças estatisticamente significantes quanto à limpeza para o sistema BR com maior quantidade de detritos remanescentes do processo de fabricação em relação ao PT e TF; após os 5 usos, os sistemas BR e PT apresentavam-se mais limpos em relação ao início do experimento, enquanto o TF permaneceu com quantidade semelhante de detritos superficiais. Ocorreu deformação em 40% do sistema BR, sendo 5% fratura e, 100% do TF, sendo 40% fratura. O sistema PT não sofreu danos consideráveis de acordo com os critérios avaliados. Por meio dos resultados obtidos neste estudo, concluiu-se que o protocolo de limpeza utilizado não proporcionou superfícies completamente limpas tanto no decorrer quanto ao final do experimento e quanto a deformação superficial, o sistema TF apresentou o pior resultado, seguido do BR, enquanto o PT que não apresentou qualquer deformação quanto aos critérios avaliados. / The aim of this study was to evaluate by scanning electron microscopy (SEM) the debris removal and deformation surface by rotary NiTi endodontic systems BioRace (BR), Protaper (PT) and Twisted File (TF) before each use, total five uses, simulating clinical conditions. A total of 75 extracted human molars whose disto-vestibular roots had curvature between 0 and 5 degrees and mesio-vestibular roots had curvature between 20 and 30 degrees according to the Weine method were selected and divided into three groups of 25 specimens. In the Group I: was used the BR system, group II was used the PT system and group III was used the TF system to shaping the mesio and distovestibular molars canals. Were used a total of five boxes to each rotary system. Initially, the instruments were examined by SEM at a magnification of 35x, then used into root canals and submitted through the cleaning protocol based on proposed by Parashos, Linsuwanont and Messer (2004) prior to sterilization for further examination by SEM, before the next use. These procedures were carried out until the last use. The cleaning data were analysed using statistical Kruskal Wallis test for global comparison and the Dunn test for individual groups comparison. The deformation data were analysed using Chi-square test for overall comparison and Fisher exact test for individual comparisons, both with 5% significance. The results showed the following statistically significant differences regarding cleaning to BR system with highest amount of debris remaining from the manufacturing process in relation to the PT and TF; after the five uses, the BR and PT systems were cleaner in relation to the initial experiment, but the TF system had the same debris amount. The deformation occurred in 40% of the BR system, with 5% fractured and 100% of the TF, with 40% fractured. The PT system has not suffered considerable damage in accordance with the criteria evaluated. The results of this study showed that the protocol did not provide cleaning surfaces completely free of debris, especially in the TF system, while for the BR and PT, resulting in cleaner surfaces at the end of the experiment compared with the dirt initial (immediately removed from their packaging). The surface deformation of TF system presented the worst results, followed by the BR and PT did not show any deformation on the criteria evaluated.

O presente estudo avaliou a interferência de operadores com diferentes proficiências no preparo de canais radiculares curvos, simulados em blocos de resina transparente. Os grupos, com 10 indivíduos cada um, foram: Grupo 1 – professores de Endodontia; Grupo 2 - alunos de especialização; Grupo 3 – alunos de odontologia Monitores de Endodontia e o Grupo 4 – alunos de graduação no início do curso de Endodontia. Cada operador instrumentou dois canais com 20 graus de curvatura, o primeiro canal era visualizado para treinamento e o segundo não. O sistema mecanizado com instrumentos rotatórios de níquel-titânio empregado foi o RaCe®. Os parâmetros de avaliação foram: tempo de instrumentação, quantidade de material removido, desvio apical e deformação dos instrumentos. Os resultados encontrados (ANOVA e Teste de Tuckey a= 0,05%), foram: Para o tempo de instrumentação, no primeiro canal, houve diferença estatística entre o grupo 1 e os grupos 3 e 4, o grupo 2 diferiu somente do grupo 4. Já, no segundo canal, não houve diferença estatística entre os grupos. Para a quantidade de material removido do primeiro canal houve diferença estatística entre os graduados (grupos 1 e 2) em relação aos graduandos (grupos 3 e 4), porém, no segundo canal, houve diferença somente entre os grupos 1 e 2. O desvio apical não apresentou diferença estatística entre os grupos em nenhuma das condições experimentais. Após a aplicação do teste do Qui-quadrado (a=0,01%), observou-se que o grupo 1 foi o que produziu as menores deformações nos instrumentos. Conclui-se que: Os desvios apicais promovidos foram semelhantes entre os grupos experimentais. Houve diminuição no tempo de instrumentação do segundo canal em relação ao primeiro, com diferença estatística nos grupos dos monitores e acadêmicos e que não houve diferença estatística entre os grupos, em relação ao tempo de instrumentação do segundo canal. Os grupos dos graduados (professores e alunos de especialização) excisaram maior quantidade de material do primeiro canal, quando comparados aos dos graduandos (monitores e acadêmicos), não havendo diferença estatística entre os grupos em relação à quantidade de material removido do segundo canal, excetuando a comparação entre os professores e os alunos de especialização, onde os primeiros desgastaram significativamente mais que os últimos. Comparados aos demais grupos, os professores produziram menores deformações aos instrumentos. / This study evaluated the interference of operators with different proficiencies in the preparation of curved canals , simulated transparent resin blocks. The groups, with 10 individuals each, were: Group 1 - professors of Endodontics; Group 2 – students of specialization; Group 3 – undergraduate dental students who had concluded the Endodontics course and Group 4 - undergraduate dental students in the beginning of the Endodontics course. Each operator prepared two canals with 20 degrees of bending, the first canal was visualized for training and second no. The rotary instrumentation used was the RaCe®. The parameters of evaluation were: time of instrumentation, amount of removed material, apical transportation and deformation of the instruments. The results (ANOVA and Test of Tuckey = 0.05%): In relation to the instrumentation time, when of the execution of the first canal, it had statistics difference between group 1 and groups 3 and 4, group 2 only differed from group 4. When of the execution of the second canal it did not have difference statistics between the groups. For the amount of material removed of the first canal it had difference statistics between the graduated (groups 1 and 2) relation to the undegraduated (groups 3 and 4). After the second canal instrumentation, only had difference between groups 1 and 2. The apical transportation did not present statistics difference enters the groups in no ne of the experimental conditions. After the application ?2 test (a=0,01%), was observed that group 1 produced lesser deformations in the instruments. Conclusions: The apical transportation was similar between the different groups. It had reduction in the time of instrumentation of the second canal in relation to the first one, with statistics difference in the groups of the monitors and academics. It did not have difference statistics between the groups, in relation to the time of instrumentation of the second canal. The groups of the graduated ones (professors and students of specialization) removed bigger amount of material of the first canal, when compared with the ones of the undergraduate (monitorial and academic). It did not have statistics difference enters the groups in relation to the amount of material removed of the second canal, excepting the comparison between the professors and the students of specialization, where the first ones had consumed significantly more than the last ones. Compared with all groups, the professors had produced minors deformations to the instruments.

A conversão biológica de biomassa celulósica em combustíveis e produtos químicos oferece elevados rendimentos de produtos para a o sucesso da economia e futuramente o potencial de custos muito baixos. A hidrólise enzimática, que converte a biomassa lignocelulósica a açúcares fermentáveis é uma etapa complexa do processo. Um requisito importante no custo-eficiente no processamento de biomassa lignocelulósica é empregar um reator que assegure, ou até mesmo promova uma elevada conversão de celulose para glicose com uma mínima dosagem de enzima. O objetivo da utilização do reator é também de processar um elevado teor de matéria seca e, consequentemente, elevados níveis de celulose que conduzem a um aumento na concentração do produto. No entanto, nos processos que empregam altas cargas de sólidos, além da viscosidade elevada do meio reacional, outros fatores afetam o processo, além da inibição do produto, sendo estes as limitações decorrentes da transferência de massa e a agitação e mistura do meio. Dentro deste contexto, o objetivo deste trabalho foi projetar um biorreator do tipo tambor rotativo para ser empregado no processo, em grande escala, de hidrólise enzimática do bagaço de cana-de-açúcar. Para alcançar este objetivo foram realizados experimentos, em escala de bancada, em um protótipo já existente no laboratório. Neste equipamento foi adicionado uma carga de sólidos de 10% (p/v) (bagaço de cana de açúcar, in natura e pré-tratado) e enzima celulase (Accellerase 1500® (Danisco)). Os resultados dos experimentos no reator mostraram um aumento na concentração de glicose (L&#8315;&#185) convertida quando comparado com os realizados em frascos Erlenmeyer (controle). Isto ocorreu devido a melhor transferência de massa e de mistura no reator, sendo este mais eficiente, pois permite uma maior área de contacto da enzima com o substrato (bagaço). / The biological conversion of cellulosic biomass to fuels and chemicals offers high yields of products for the success of the economy and future the potential for very low costs. Enzymatic hydrolysis that converts fermentable sugars in lignocellulosic biomass is a complex step in this process. An important requirement in cost-efficient in the processing of lignocellulosic biomass is to employ a reactor that will ensure, or even promote, maximal conversion of cellulose to glucose with a minimum dosage of enzyme. The purpose of using the reactor is also for to process of high dry matter contents and therefore higher levels of cellulose that will also drive up the product concentration. However, the processes that emply high solid loadings, in addition to the high viscosity of the reaction mixture and other factors than product inhibition, notably mixing and mass transfer limitations. Within this context, the aim of this work was to design a bioreactor rotary drum to be used in the process, with largescale enzymatic hydrolysis from sugarcane bagasse. To achieve this objective were performed in a bench scale, with prototype already existing in the laboratory. In this equipment was added a solids loading of 10% (w/v) (sugar cane bagasse, raw and pretreated) and cellulose enzyme (Accellerase 1500® (Danisco)). The results of the reactor experiments showed an increase in glucose concentration (L&#8315;&#185) converted when compared with those realized in Erlenmeyer flasks (control). This occurred because the mass transfer and mixing in the reactor is more efficient because it allows greater contact area of the enzyme with the substrate (sugarcane bagasse).

Inúmeras são as vantagens da utilização de instrumentos rotatórios de níquel-titânio no preparo químico-cirúrgico, como por exemplo, melhor modelagem dos canais curvos e uma diminuição significativa no tempo de trabalho. Todavia, a maior preocupação no uso desses instrumentos tem sido a sua fratura, principalmente, por sua ocorrência estar ligada a diferentes fatores. O objetivo do presente estudo foi avaliar a influência da velocidade de rotação e do número de usos, no tempo de trabalho e na ocorrência de fraturas de instrumentos de dois sistemas rotatórios de níquel-titânio (K3 e RaCe), em canais simulados com mesmo ângulo de curvatura. Foram avaliados os instrumentos 25/.04 dos dois sistemas nas velocidades de 180, 350, 600 rpm ao instrumentarem 5 mm referentes à curvatura dos canais simulados. Para cada velocidade foram utilizadas limas com 1, 2 e 3 usos. Um contra-ângulo foi adaptado a um dispositivo calibrado para realizar movimentos padronizados de penetração nos canais simulados. Foram mensurados: o tempo necessário para instrumentar a curvatura do canal e a quantidade de fraturas ocorridas. Os resultados obtidos foram submetidos a ANOVA sendo em seguida empregado o teste de Tukey (&#945;=5%). Sob as condições desse experimento, o aumento da velocidade diminuiu o tempo de instrumentação em ambos os sistemas. Os instrumentos RaCe prepararam o canal em menor tempo do que os instrumentos K3 nas velocidades de 350 e 600 rpm (p<0,05), não havendo diferença em 180 rpm (p>0,05). Ocorreu maior número de instrumentos fraturados nas velocidades de 180 e 600 rpm para o sistema RaCe e de 600 rpm para o K3, e nenhuma fratura na velocidade de 350 rpm para ambos. O número de usos não influenciou o tempo de trabalho para nenhum sistema (p>0,05), porém, o número de fraturas aumentou proporcionalmente ao aumento do número de usos, exceto na velocidade de 350 rpm na qual não ocorreram fraturas. Os instrumentos RaCe apresentaram maior índice de fratura para a velocidade de 180 rpm (30%) do que para 600 rpm (13,33%). A velocidade de 350 rpm foi a mais segura para os instrumentos de ambos os sistemas. / Use of nickel-titanium rotary instruments has many advantages like better shaping of curved canals and lower working time. However, instrument fracture has always been a serious concern in root canal treatment because it involves a lot of factors. The aim of this study was to evaluate the influence of rotational speed and number of uses on the preparation time and incidence of fractures of K3 and RaCe instruments, using simulated root canals with the same angle of curvature. Nickel-titanium 25/.04- tapered instruments of both rotary systems were tested at 180, 350 and 600 rpm during shaping of 5 mm curvature’s extent. The files were used 3 times in each rotational speed. A contra-angle electric handpiece was mounted on a machine that was calibrated to deliver a constant penetration movement. Working time and incidence of fractures were measured. The results were analyzed statistically using a one-way analysis of variance with a post-hoc Tukey test (&#945;=5%). Under the conditions of this study, higher rotational speeds reduced preparation time for both rotary systems. RaCe instruments showed lower preparation time than K3 instruments at 350 and 600 rpm (p<0,05). There was no significant difference at 180 rpm (p>0,05). There was a higher incidence of fractures at 180 and 600 rpm for RaCe instruments and at 600 rpm for K3 instruments. No file breakage occurred at 350 rpm for both instruments. Preparation time was not influenced significantly by the frequency that the files were used (p>0,05). Incidence of fractures increased with an increase in the number of file usage, unless at 350 rpm in which none of the files fractured. At 180 rpm, RaCe instruments showed a higher incidence of breakage than at 600 rpm. Rotational speed of 350 rpm was the safest for both kind of instruments tested in this study.

O objetivo deste estudo ex vivo foi avaliar o preparo biomecânico e a obturação de canais radiculares ovais utilizando os sistemas ProTaper, WaveOne, Reciproc e Self-Adjusting File. Com esta finalidade avaliou-se: 1) área, perímetro, circularidade, diâmetro maior, diâmetro menor, área de superfície, volume e SMI após o preparo biomecânico, por meio de microtomografia computadorizada (&mu;TC); 2) percentual volumétrico de espaços vazios após a obturação do canal, por meio de &mu;TC; 3) resistência de união (RU) e tipo de falha ocorrida após teste de push-out; e 4) a interface dentina/material obturador em microscopia eletrônica de varredura (MEV). Cem caninos inferiores humanos foram escaneados no microtomógrafo SkyScan 1174v.2. Após o preparo do terço cervical dos canais, os dentes foram distribuídos em 4 grupos (n=25), de acordo com o sistema usado no preparo biomecânico: ProTaper; WaveOne; Reciproc; Self-Adjusting File (SAF). Após a segunda &mu;TC, 18 espécimes de cada grupo foram redistribuídos em dois grupos (n=9), de acordo com a técnica de obturação: Técnica Modificada da Onda Contínua de Condensação e técnica recomendada pelo fabricante. Os sete espécimes restantes de cada grupo constituíram os grupos controle negativo e positivo. Após a TC dos espécimes obturados, as raízes foram seccionadas transversalmente em fatias de 1 mm de espessura correspondentes às regiões cervical, média e apical. A RU foi avaliada pelo teste de push-out e as falhas após desunião observadas em microscópio digital. Após preparo para MEV, avaliou-se a interface adesiva de forma qualitativa nominal e ordinal pelo estabelecimento e determinação de escores. No conjunto, a análise dos parâmetros avaliados no preparo biomecânico mostraram que as alterações mais significativas ocorreram nos grupos ProTaper e WaveOne. Os resultados no grupo Reciproc ficaram em um nível intermediário, enquanto as menores alterações foram observadas no grupo SAF (ANOVA, p<0,05). Em relação à obturação, a Técnica Modificada da Onda Contínua de Condensação apresentou menor percentual volumétrico de espaços vazios que a técnica recomendada pelo fabricante apenas no terço cervical (Kruskall-Wallis, p<0,05). Após o teste de push-out, a análise das médias indicou RU (MPa) significativamente maior nos espécimes obturados pela técnica do fabricante em comparação com a Técnica Modificada de Onda Contínua de Condensação (teste t para amostras independentes, p<0,05). Em todos os grupos foi verificado maior percentual de falhas adesivas, com predominância de falhas mistas na técnica do fabricante e de falhas adesiva na dentina na Técnica Modificada de Onda Contínua de Condensação. Em MEV, não houve tags na maioria dos espécimes obturados pela Técnica Modificada da Onda Contínua de Condensação e quando presentes, eram pequenos e irregularmente distribuídos. Nos espécimes obturados pela técnica recomendada pelo fabricante observou-se formação de tags longos e bem distribuídos, principalmente no terço apical (teste de Friedman, p<0,05). Concluiu-se que todos os sistemas resultaram em alterações nos parâmetros bidimensionais e tridimensionais do canal após o preparo biomecânico; a técnica recomendada pelo fabricante resultou em maior volume de espaços vazios no terço cervical e maior RU do material obturador do que a Técnica Modificada de Onda Contínua de Condensação. Obs: tese completa no site: https://rapidshare.com/files/963588082/Tese_Prof._Dr._Marco_Versiani_FORP_USP_2012.pdf (na pagina que abrir, clicar no botao \"download\"). / The purpose of this ex vivo study was to evaluate the biomechanical preparation and obturation of root canals using ProTaper, WaveOne, Reciproc and Self-Adjusting File systems. It was evaluated: 1) area, perimeter, roundness, major diameter, minor diameter, surface area, volume and SMI after biomechanical preparation, using microcomputed tomography (&mu;TC), 2) percentage volume of voids in the obturation material by means of &mu;TC, 3) bond strength (BS) and type of failure after the pushout test, and 4) the analysis of the interface dentin / filling material using scanning electron microscopy (SEM). One-hundred human mandibular canines were scanned in the SkyScan 1174v.2 device. After preparing the coronal third of the canals, the teeth were divided into 4 groups (n=25), according to the biomechanical preparation system used: ProTaper, WaveOne, Reciproc, and Self-Adjusting File (SAF). After the second TC, eigthteen specimens of each group were assigned to two groups (n=9), according to the obturation technique: the Modified Continuous Wave of Condensation Technique and the technique recommended by the manufacturer. The remaining seven specimens of each group were used as negative and positive controls. After scanning, the obturated specimens were sectioned perpendicularly to its long axis into 1-mm slice thickness of the coronal, middle and apical thirds. The bond strength (BS) was performed by the push-out test and, after dislodgments, the failures were observed in a digital microscope. The specimens were processed for SEM analysis to observe bonding interface formation and resin tag density using a four-step scale method. Overall, the analysis of the biomechanical parameters showed that the most significant changes in the root canal occurred in the ProTaper group and WaveOne groups. Reciproc results were in an intermediate level and smaller changes were observed in the SAF group (ANOVA, p<0.05). In the coronal third, the Modified Continuous Wave of Condensation Technique showed a lower percentage volume of voids than the technique recommended by the manufacturer (Kruskal-Wallis test, p<0.05). After the push-out test, the analysis indicated the mean BS (MPa) was significantly higher in specimens filled by the manufacturer\'s technical than the Modified Continuous Wave of Condensation Technique (t test for independent samples, p<0.05). The adhesive failures were frequent in all groups. The Modified Continuous Wave of Condensation Technique showed the highest percentage of adhesive failure in dentin while in the technique recommended by the manufacturer, mixed failure was predominant. Overall, in SEM analysis, no tags were observed in most of the specimens filled by the Modified Continuous Wave of Condensation Technique. When present, they were small and irregularly distributed. The specimens filled by the technique recommended by the manufacturer showed long and well-distributed tags, especially in the apical third (Friedman test, p<0.05). It was concluded that all systems promoted root canal changes after the biomechanical preparation, the obturation technique recommended by the manufacturer resulted in a higher volume of voids in the coronal third and BS of the Modified Continuous Wave of Condensation Technique group.

O presente trabalho teve por objetivo avaliar e comparar dois sistemas de aplicação de agrotóxicos em citros visando à redução do volume de aplicação com base no estudo da quantidade de produto que permanece no alvo (deposição) e análise das gotas. Na citricultura utilizam-se altos volumes de aplicação (de 2000 a 5000 L.ha-1) para o controle de pragas e doenças incrementando os custos operacionais, por esse motivo, atualmente vem-se desenvolvendo diversos sistemas de aplicação com tecnologia sofisticada visando diminuir esses volumes para 200 ou 500 L.ha-1 mas permitindo que a quantidade de produto depositado no alvo seja eficaz no controle de pragas e doenças. Procuramos avaliar dois sistemas de aplicação de agrotóxicos com um pulverizador de jato transportado. Os sistemas de aplicação utilizaram os atomizadores rotativos de discos e os bicos hidráulicos para efeito comparativo do desempenho. Foi realizada uma pulverização em duas passadas para cada sistema sobre uma amostra de quatro árvores. Utilizaram-se papéis hidrosensíveis, folhas e placas de vidro para a coleta dos dados. Para a análise da gota utilizou-se o software de leitura visual e-Sprinkle e a análise de deposição foi realizada com cromatografia gasosa e cromatografia de permeação em gel. Concluiu-se que o sistema de aplicação com atomizadores rotativos mostrou resultados favoráveis de deposição quando comparado com o sistema de aplicação com bicos hidráulicos, uma vez que esses resultados não foram significativamente diferentes. O que resulta bastante importante é que o sistema de aplicação com atomizadores rotativos utilizou um quinto do volume de aplicação quando comparado ao sistema com bicos hidráulicos, pelo que se deve considerar de vital importância o aspecto econômico para trabalhos complementares. / The aim of the work was to evaluate and compare two application spray systems of pesticides in citrus, aiming the reduction of the application volume rate in based in the amount of product that remains in the target (spray deposition) and distribution of the drops. Actually in the citrus orchard high application volumes rates for the pest control are used increasing the operational costs. The application system must be based in sophisticated technology to reduce the application volumes rates and also be efficient in the pest control. For such we evaluated two pesticides application systems with an air carrier sprayer. The application systems used were the rotary discs atomizers and the hydraulic nozzles, to compare the performance based in the applied volume rates, spray deposition and droplets distribution. A spraying run for each system was performed on a random sample of four trees for each system, water-sensitive papers, leaves and glass slides had been used for data collection. The water-sensitive papers were analyzed with visual imaging software (e-Sprinkle) and the spray deposition was analyzed with gas chromatography and gel permeation chromatography. The application system with rotary discs atomizers used reduced application volumes rates and had less deposit than hydraulic nozzles but did not significantly differents. Those results were important because the application system with rotary discs atomizers only used fifth of the application volume rate compared with hydraulic nozzles, must be consider of vital importance the economical aspect to complementary works.