Introdução: A evolução dos instrumentos de NiTi pode ser dividida em gerações de acordo com algumas modificações tais como: tratamento térmico da liga, secção transversal e movimento utilizado para o preparo do canal, que pode ser movimento rotatório contínuo ou movimento oscilatório assimétrico. Essas mudanças tem como objetivo prover maior flexibilidade aos instrumentos, permitindo uma melhor modelagem do canal, com menor desvio e menor risco de perfurações. Outro aspecto relevante é a maior resistência à fadiga cíclica, das ligas com tratamento térmico, colaborando para uma maior resistência à fratura do instrumento. Objetivos: Este estudo comparou a fadiga cíclica, o transporte do canal , a capacidade de centralização e o volume do canal pós preparo, produzidos pelos sistemas TF Adaptive e Navigator EVO, quando utilizados em rotação contínua ou no movimento Adaptive. Métodos: Quarenta raízes mésio-vestibulares de molares superiores foram analisadas através de micro-CT antes e depois do preparo do canal radicular com os dois sistemas e dois movimentos (Adaptive e Rotação Contínua). As amostras foram divididas em quatro grupos: TFA – instrumentos TF Adaptive utilizados no movimento Adaptive; TFC –instrumentos TF Adaptive utilizados em rotação contínua; NA – instrumentos Navigator EVO utilizados no movimento Adaptive; e NC – instrumentos Navigator EVO utilizados em rotação contínua. Adaptive; e NC – instrumentos Navigator EVO utilizados em rotação contínua. Os canais radiculares foram preparados até instrumentos 35.04. O transporte apical, a capacidade de centralização e o volume de preparo foram analisados utilizando-se micro-CT em três níveis: 3, 6 e 9mm do ápice.O teste de fadiga cíclica foi realizado utilizando um equipamento apropriado, onde, dez instrumentos de cada marca foram utilizados em um contraângulo redutor 6:1 e um motor elétrico com controle de torque, com programas prédefinidos ‘‘custom mode'' e ‘‘TF Adaptive'' para ativar os instrumentos 25.06 e 35.04.Os resultados foram analisados com os testes Kruskal-Wallis eDunn para se verificar o transporte do canal, a capacidade de centralização e o volume do canal. O teste Student-T foi usado para avaliar a fadiga cíclica (P = 0,05). Conclusões: Ambos sistemas podem ser usados no movimento Adaptive ou em rotação contínua. Porém, a resistência à fratura dos instrumentos foi maior quando utilizados em rotação contínua. Pouco transporte de canal ocorreu, quando os canais mésio-vestibulares de molares superiores foram preparados até instrumentos 35.04. / Introduction: The evolution of NiTi instruments can be divided in generations, according to changes like in the NiTi alloy, heat treatment, cross-section format, and in the movement used for root preparation that goes form continuous rotation to asymmetric oscillation. These changes aim to provide greater flexibility to the instruments, allowing a better shaping, with less transportation and risk of perforation. Other aspect is the increased fracture resistance of the alloys with heat treatment, which is a big concern about NiTi instruments. Aim: This study compared the cyclic fatigue and the canal transportation promotedby TF Adaptive and Navigator EVO systems when used with two different motions. Methods: Forty mesiobuccal roots of maxillary molars were scanned using micro-CT imaging before and after root canal preparation with the two instrument systems two motions (adaptive and continuous rotation). Samples were divided into four groups: TFA – TF Adaptive instruments under adaptive motion; TFC - TF Adaptive instruments under continuous motion; NA - Navigator instruments under adaptive motion; and NC – Navigator instruments under continuous motion. Root canals were prepared until 35.04 instruments. Apical transportation, centering ability and volume were analyzed using micro- CT at three levels: 3, 6 and 9 mm from the apex. The cyclic fatigue tests were performed using a custom-made device. Ten instruments of each brand were activated by using a 6:1 reduction handpiece powered by a torque-controlled motor using the preset programs ‘‘custom mode'' and ‘‘TF Adaptive'' to activate25.06 and 35.04 instruments. Data were analyzed with Kruskal-Wallis and Dunn tests were used to assess canal transportation, centering ability and canal volume. Student-T test was used to evaluate cyclic fatigue (P = .05). Conclusions: Both systems can be used under adaptive or continuous rotation. However; the lifespan of the instruments was higher when used under continuous rotation. Little canal transportation occurred when mesiobuccal root canals from maxillary molars were prepared until 35.04instruments.

nÃo hà / The main aim of endodontic therapy is the cleaning and shaping of the root canal and the complete filling of the entire root canal system. Adhesion is defined as the atomic or molecular attraction between two surfaces that touch, caused by the interfacial force of attraction between the molecules or atoms of both materials. The adhesion can be chemical, mechanical or a combination of both. The perfect adhesion of the filling to the canal walls is a constant search through the improvement and introduction of new materials used in this phase of treatment, with emphasis on the sealer that promotes the union of the solid part of the filling, gutta-percha, to the walls of the root canal. This study aimed to evaluate the bond strength of three root canal sealers by the push-out test, that is quite reliable in view of the accuracy and reproducibility of results. Thirty human upper canines teeth were selected and sectioned at the cementoenamel junction to remove the crown and 2 mm from the apex. All canals were enlarged with Gates-Glidden drills #1-5 and finished the preparation with Peeso drill #6. Between every drill exchange, 1 ml of 2.5% sodium hypochlorite was used as irrigating solution. The roots were sectioned in 1 mm slices and filled according to the root canal sealer, subdividing each group according to the root third (n=25). They were then filled with the sealer as follow: Group 1, AH Plus, Group 2, MTA Fillapex and Group 3 Pulp Canal Sealer. The results showed statistically significant superiority of the AH Plus compared to the other two sealers and Pulp Canal Sealer in relation to the MTA Fillapex. Regarding the root thirds, only the Pulp Canal SealerÂs group showed statistically significant differences, with superiority of the apical third compared to cervical and middle thirds. It is concluded that AH Plus showed the best values of bond strength, regardless of the root third. / Os principais objetivos do tratamento endodÃntico sÃo a limpeza, a modelagem do canal radicular e a completa obturaÃÃo de todo o sistema de canais radiculares. Uma das propriedades exigidas do material obturador à a adesÃo, que à definida como a atraÃÃo molecular ou atÃmica entre duas superfÃcies que se tocam, causada pela forÃa de atraÃÃo interfacial existente entre as molÃculas ou Ãtomos de dois materiais. A adesÃo pode ser quÃmica, mecÃnica ou a combinaÃÃo de ambas. A perfeita adesÃo da obturaÃÃo Ãs paredes do canal à uma busca constante atravÃs do aprimoramento e lanÃamento de novos materiais utilizados nessa fase do tratamento, com Ãnfase no cimento endodÃntico, responsÃvel pela uniÃo da parte sÃlida da obturaÃÃo, a guta percha, Ãs paredes do canal radicular. Este estudo teve como objetivo avaliar a forÃa de adesÃo de trÃs cimentos endodÃnticos atravÃs do teste de push-out, que à um teste bastante confiÃvel, tendo em vista a precisÃo dos resultados e sua reprodutibilidade. Trinta caninos superiores humanos extraÃdos foram selecionados e seccionados na junÃÃo cemento-esmalte, descartando-se a coroa e removendo-se 2mm do Ãpice radicular. Em seguida, os canais radiculares foram preparados com brocas de Gates-Glidden #1 a 5 e finalizados com a broca de Peeso #6, gerando um preparo do canal radicular de forma cilÃndrica e com 1,5 mm de diÃmetro. Logo apÃs, as raÃzes foram seccionadas transversalmente em fatias de 1mm de altura, sendo logo apÃs divididas em 3 grupos de acordo com o cimento utilizado e 3 sub grupos, de acordo com o terÃo radicular (n=25). Os espÃcimes foram entÃo preenchidos com o cimento da seguinte forma: Grupo 1, cimento AH Plus, Grupo 2, cimento MTA Fillapex e Grupo 3, cimento Pulp Canal Sealer. Os resultados mostraram superioridade com diferenÃa estatisticamente significante do cimento AH Plus em relaÃÃo aos outros dois cimentos e do Pulp Canal Sealer em relaÃÃo ao MTA Fillapex. Em relaÃÃo aos terÃos radiculares, somente no grupo do Pulp Canal Sealer foram encontradas diferenÃas estatisticamente significantes, com superioridade do terÃo apical em relaÃÃo aos terÃos cervical e mÃdio. Conclui-se que o cimento AH Plus apresentou os melhores valores de forÃa de adesÃo, independente do terÃo radicular.

A guta-percha associada a um cimento endodÃntico representa o recurso mais usado para a obturaÃÃo dos canais radiculares. Esta associaÃÃo, porÃm, nÃo possui adesividade Ãs paredes de dentina, fato este que pode ensejar falhas na massa obturadora no interior do canal radicular e induzir a fraturas radiculares. O sistema Resilon/Epiphany, como alternativa à guta-percha na obturaÃÃo endodÃntica foi lanÃado com a proposta de formaÃÃo de um monobloco (adesÃo de material obturador + dentina), de modo a possiblitar o aumento da resistÃncia a fratura, entretanto, esse à ainda questionado na literatura. O propÃsito desta pesquisa foi avaliar a resistÃncia à fratura de raÃzes obturadas endodonticamente com a guta-percha/AH-Plus e com o sistema Resilon/Epiphany, variando-se a tÃcnica de obturaÃÃo. Foram selecionadas 60 raÃzes dentais humanas extraÃdas, que foram divididas em seis grupos de dez. O grupo I nÃo sofreu intervenÃÃo endodÃntica. O grupo II foi instrumentado e nÃo obturado, os grupos III e IV foram instrumentados e obturados com guta-percha/AH-Plus, sendo o grupo III obturado, empregando-se a tÃcnica da condensaÃÃo lateral, e o grupo IV a tÃcnica hÃbrida de Tagger. Os grupos V e VI foram instrumentados e obturados com o sistema Resilon-Epiphany, variando da mesma forma as tÃcnicas de obturaÃÃo, assim como nos grupos III e IV. As raÃzes foram submetidas à forÃa de compressÃo, utilizando uma mÃquina universal de ensaios (Kratos) em velocidade de carga de 0,5mm/min, registrando-se em seguida o valor da carga quando da constataÃÃo da fratura radicular. Os dados obtidos foram submetidos ao ANOVA (significÃncia de 5%) e teste Tukey. Concluiu-se que os grupos obturados com o sistema Resilon/Epiphany apresentaram maior resistÃncia à fratura em relaÃÃo aos grupos obturados com guta-percha/AH-Plus, porÃm sem significÃncia estatÃstica. Enfatiza-se, entretanto, que o grupo VI (Resilon/Epiphany, tÃcnica hÃbrida de Tagger) apresentou diferenÃas estatÃsticas significativas em relaÃÃo ao grupo I (sem intervenÃÃo endodÃntica) e II (instrumentado e nÃo obturado); a presenÃa de material obturador à fundamental para a manutenÃÃo de boa resistÃncia à fratura, pois o grupo II, instrumentado e nÃo obturado, exibiu a menor resistÃncia a fratura entre os grupos; a tÃcnica de termoplastificaÃÃo do material obturador interferiu no resultado final das resistÃncias mensuradas, porÃm sem diferenÃas estatÃsticas significativas. / Gutta-percha, in combination with a variety of sealers, is the most commonly used material for root canal filling. This association presents no adhesiveness to the root structure. Resilon cones and resinous cement (Epiphany) were introduced on the market that, in association with a self-conditioning primer, would alow a solid monoblock to be obtained. The Resilon/Epiphany system forms a monoblock within the canals that bonds to the dentin walls. It has potential to strengthen the walls against fracture. The material was proposed as an alternative to gutta-percha. The purpose of this in vitro study was to evaluate the fracture resistance of root canals filled with gutta-percha/ AH Plus and root canals filled with Resilon/Epipanhy system. Sixty extracted single rooted teeth were selected. The teeth were randomly categorized into 6 groups of 10 teeth each as follows: Group I: teeth without endodontic treatment; Group II: teeth were instrumented but without endodontic obturation; Group III: teeth were instrumented and obturated with gutta-percha in conjunction with AH Plus sealer and obturated with lateral condensation technique; Group IV: teeth were instrumented and obturated with gutta-percha in conjunction with AH Plus sealer and obturated with hybrid Tagger`s techinique; Group V: teeth were instrumented and obturated with Resilon/Epiphany system and obturated with lateral condensation technique; Group VI: teeth were instrumented and obturated with Resilon/Epiphany system and obturated with hybrid Tagger`s technique. The roots were submited to the compressive test. A Kratos Universal Testing Machine was used to apply a load to each specimen at a crosshead speed of 0,5mm per minute until the root fracture. The results were submited to ANOVA test ( 5%) and Tukey test. With respect to the fracture resistance there was no statiscally significant difference between the group filled with gutta-percha and the Resilon/Epiphany system. However, the group VI showed statistically significant difference when compared with group I and group II. The presence of the endodontic material is very important to maintenance the good fracture resistance, because the group II showed the worst results. The thermoplastic technique presented better results, but within statistically significant differences.

Orientador: Adriana de Jesus Soares / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-19T22:30:40Z (GMT). No. of bitstreams: 1 Winocur_EstelaMartaDoffode_D.pdf: 39787975 bytes, checksum: dfb0acb3bf358d565765b0c840c32986 (MD5) Previous issue date: 2012 / Resumo: O objetivo deste estudo in vitro foi avaliar o selamento apical após obturação endodôntica, em dentes humanos preparados com e sem ampliação do forame apical, com o Sistema Rotatório Mtwo® (VDW, Munique, Alemanha). Vinte prémolares inferiores foram divididos em dois grupos. No Grupo I, os canais radiculares foram preparados 1mm além do forame apical e, no Grupo II, 1 mm aquém do CRC. Os dentes foram preparados para avaliação no MEV (JEOL, Modelo JSM 5600LV, Tókio, Japão) e as imagens do forame apical obtidas em aumento de 75x, em posições padronizadas, permitindo a mensuração da área foraminal antes, após o preparo e após a obturação. Por meio do processo do Sistema de Subtração de Imagens (Emago® Sistema de Diagnóstico Oral, Louwesweg, Amsterdam, Holanda), foi possível identificar as variações de forma e transporte do forame apical assim como o nível de preenchimento de sua circunferência pelo cimento obturador Pulp Canal Sealer (Sybron Endo, USA) após o preparo. Os resultados encontrados, submetidos à análise estatística, permitiram concluir que os dentes do Grupo I apresentaram maior diâmetro foraminal que os do Grupo II (Teste Anova, p<0,05) e que houve diferença estatisticamente significante quanto ao transporte do forame (Teste Exato de Fisher, p=0,0108); quanto ao selamento apical houve diferença estatisticamente significante entre os grupos I e II (Testes t de Student e Exato de Fisher, p=0,0007) sendo que, no Grupo I, ocorreram selamento em 100% dos espécimes analisados / Abstract: The aim of this in vitro study was to evaluate the apical root sealing after endodontic filling, in human teeth that were prepared with and without apical foramen enlargement by Mtwo® Rotary System (VDW, Munich, Germany). Twenty mandibular premolars were divided in two groups. Group I had root canals prepared 1mm beyond apical foramen, and in Group II, 1mm below RCL. Teeth were prepared for an electronic microscopy analysis (JEOL, Model JSM 5600LV, Tokyo, Japan). Apical foramen images were 75 times magnified, at standardized positions, allowing measurements from apical foramen area before and after root canal preparation, and after root filling. By using the Image Subtraction System (Emago®, Oral Diagnostic System, Louwesweg, Amsterdam, Netherlands) apical foramen shape modifications and transportation as well as the level of its circumferential filling by Pulp Canal Sealer cement (Sybron Endo, USA) after root canal preparation were accessed. After statistical analysis, results allowed to conclude that Group I teeth showed larger foraminal diameter than Group II (Anova Test, p<0,05) and that foramen transportation difference was statistically significant (Fisher Exact Test, p=0,0108); apical foramen sealing also differed statistically between groups I and II (Student t Test and Fisher Exact Test, p=0,0007) and that 100% of Group I specimens showed apical root sealing / Doutorado / Endodontia / Doutor em Clínica Odontológica

Development Related Termination of the Root Apical Meristem Activity Abstract Root system architecture is modulated through growth and branching of individual roots, while the growth is strictly regulated via long term apical meristem (RAM) maintenance and cell elongation. RAM activity is not consistent during root on- togeny, which was shown in several dicotyledonous species as change in root meristem structure and decline in root growth rate during individual root development. This thesis is focused on changes in extent and arrangement of meristematic tissues and their derivatives within adventitious roots of Acorus calamus and Oryza sativa during long term cultivation. Changes in meristem and elongation zone length, the root cap length, radial tissue complexity, as well as the changes in root hair emergence, etc., are put into relation with quantified expression level of selected important regulatory elements taking part in RAM maintenance (WOX and SCR family transcription factors). Methodology and approach for future research in this field are outlined. Keywords: Root, Apical Meristem, Root System Architecture, RAM Termination

This thesis focuses on the study of TTL protein family in the model species Arabidopsis thaliana. It sums up available published data on this so far poorly studied genes and presents newly gained experimental data. Main emphasis is given to TTLs cellular localization in possible relationship to their physiological function. Presented thesis comprises of in silico analysis of TTL proteins, but also the creation and microscopy analysis of TTL-mRuby2 and TTL-GFP fusion proteins in transient and permanent transformants. Powered by TCPDF (www.tcpdf.org)

2 p. / Alfalfa varieties differ in fall dormancy, defined as growth during the fall. Nondormant alfalfa varieties are usually planted in mild winter areas for their ability to grow in the fall. However, fall growth of nondormant alfalfa may be undesirable in areas subject to repeated frosts or freezes. Nondormant, very nondormant, and extremely nondormant alfalfa varieties (fall dormancy class 8, 9, and 10) are adapted to elevations below 4000 feet in Arizona. Other dormancy classes not included in this publication are moderately nondormant varieties (fall dormancy class 7) which may be grown from 3000 to 5000 feet, and semi-dormant and dormant varieties (fall dormancy 6 and below) which are adapted to colder winter areas above 4000 feet.

Il est généralement admis que la végétation peut stabiliser les pentes naturelles et artificielles contre les glissements de terrain superficiel. Par rapport au rôle mécanique, les racines renforcent le sol d'une pente en fournissant une cohésion additionnelle (cr). La quantification des cr est une étape essentielle pour évaluer la stabilité des pentes, quantifiée par le facteur de sécurité (FoS, défini par le ratio entre les forces de la résistance et les forces motrices sur une pente). La plupart des modèles prédictifs de cr existants ne prennent pas en compte la dynamique racinaire à l'échelle spatiale et temporelle qui peut conduire à une hétérogénéité de renforcement des racines. Ainsi, cette thèse vise à caractériser, quantifier et modéliser la répartition spatiale et temporelle de la dynamique racinaire ainsi que son impact sur la cr estimée. La distribution, croissance et mortalité racinaire ont été échantillonnées à l'aide de monolithes et de rhizotrons à deux altitudes dans des forêts mixtes et naturellement régénérées dans les Alpes françaises, composées d'îlots et de trouées. Avec les méthodes de modélisation statistique, une série de facteurs abiotiques et biotiques affectant la dynamique racinaire ont été étudiés. Pour quantifier les cr, une méta-analyse a été effectuée et les divers algorithmes de modélisation ont été employés et leurs résultats comparés. Cette étude a montré que: (i) dans un écosystème à espèces mixtes, la densité racinaire influence davantage les cr que les propriétés de la qualité racinaire; (ii) tous les facteurs abiotiques (altitude, paysage écologique, profondeur du sol et mois) peuvent faire varier la densité racinaire selon des conditions différentes du sol ; (iii) lors de l'observation de 1,5 ans à l'aide de rhizotrons, le cr augmente continuellement, rapidement dans la saison active et lentement pendant la saison dormante, mais cette augmentation est dépendante de la profondeur du sol, de l'altitude et du patch écologique ; (iv) malgré le fait que les racines les plus fines (]0, 1] mm en diamètre) soient les plus actives dans le cycle de nutritions et de carbone (selon des publications précédentes), elles contribuent peu au renforcement mécanique de terrain. Cette étude a permis d'élargir et d'approfondir nos connaissances sur le rôle des racines dans l'éco-ingénierie. / It is largely recognized that vegetation can stabilize artificial and natural slopes against shallow landslides. Mechanically, plant roots reinforce soil on a slope by providing an additional cohesion (cr). Quantification of cr is a key step to estimate the stability of a given slope, usually quantified by the Factor of Safety (FoS, defined as the ratio between resisting forces and the driving forces on a slope). Most existing cr predictive models do not take into consideration spatial and temporal root dynamics which result in heterogeneous root reinforcement along a vegetated slope. Therefore, this thesis aims to characterize, quantify and model the spatial and temporal patterns in root dynamics and their impact on the estimation of cr. Root distribution, growth and mortality were measured using monoliths and rhizotrons installed at two altitudes in naturally regenerated mixed forests in the French Alps. These forests are composed of trees growing in groups (tree islands) with large gaps between the islands. Using statistical modeling approaches, abiotic and biotic factors affecting root dynamics were investigated. For quantifying cr, a meta-analysis was performed and different modeling algorithms were employed and results compared. Based on these studies, the following conclusions were made: (i) in a mixed, mature forest ecosystem root density influenced cr more than root mechanical properties; (ii) all abiotic factors (altitude, type of vegetation patch, soil depth and month) significantly affected root quantity to different degrees, depending on soil conditions; (iii) during the 1.5 years' observations in rhizotron, cr increased rapidly during the growing season and more slowly in the dormant season but the increment increase was largely dependent on soil depth, altitude and vegetation patch. (iv) The finest roots (]0, 1] mm in diameter), which are considered the most important for nutrient and carbon cycling, contributed little to mechanical reinforcement of the soil. Results are discussed with regard to ecological engineering strategies for unstable slopes.

Introdução: A evolução dos instrumentos de NiTi pode ser dividida em gerações de acordo com algumas modificações tais como: tratamento térmico da liga, secção transversal e movimento utilizado para o preparo do canal, que pode ser movimento rotatório contínuo ou movimento oscilatório assimétrico. Essas mudanças tem como objetivo prover maior flexibilidade aos instrumentos, permitindo uma melhor modelagem do canal, com menor desvio e menor risco de perfurações. Outro aspecto relevante é a maior resistência à fadiga cíclica, das ligas com tratamento térmico, colaborando para uma maior resistência à fratura do instrumento. Objetivos: Este estudo comparou a fadiga cíclica, o transporte do canal , a capacidade de centralização e o volume do canal pós preparo, produzidos pelos sistemas TF Adaptive e Navigator EVO, quando utilizados em rotação contínua ou no movimento Adaptive. Métodos: Quarenta raízes mésio-vestibulares de molares superiores foram analisadas através de micro-CT antes e depois do preparo do canal radicular com os dois sistemas e dois movimentos (Adaptive e Rotação Contínua). As amostras foram divididas em quatro grupos: TFA – instrumentos TF Adaptive utilizados no movimento Adaptive; TFC –instrumentos TF Adaptive utilizados em rotação contínua; NA – instrumentos Navigator EVO utilizados no movimento Adaptive; e NC – instrumentos Navigator EVO utilizados em rotação contínua. Adaptive; e NC – instrumentos Navigator EVO utilizados em rotação contínua. Os canais radiculares foram preparados até instrumentos 35.04. O transporte apical, a capacidade de centralização e o volume de preparo foram analisados utilizando-se micro-CT em três níveis: 3, 6 e 9mm do ápice.O teste de fadiga cíclica foi realizado utilizando um equipamento apropriado, onde, dez instrumentos de cada marca foram utilizados em um contraângulo redutor 6:1 e um motor elétrico com controle de torque, com programas prédefinidos ‘‘custom mode'' e ‘‘TF Adaptive'' para ativar os instrumentos 25.06 e 35.04.Os resultados foram analisados com os testes Kruskal-Wallis eDunn para se verificar o transporte do canal, a capacidade de centralização e o volume do canal. O teste Student-T foi usado para avaliar a fadiga cíclica (P = 0,05). Conclusões: Ambos sistemas podem ser usados no movimento Adaptive ou em rotação contínua. Porém, a resistência à fratura dos instrumentos foi maior quando utilizados em rotação contínua. Pouco transporte de canal ocorreu, quando os canais mésio-vestibulares de molares superiores foram preparados até instrumentos 35.04. / Introduction: The evolution of NiTi instruments can be divided in generations, according to changes like in the NiTi alloy, heat treatment, cross-section format, and in the movement used for root preparation that goes form continuous rotation to asymmetric oscillation. These changes aim to provide greater flexibility to the instruments, allowing a better shaping, with less transportation and risk of perforation. Other aspect is the increased fracture resistance of the alloys with heat treatment, which is a big concern about NiTi instruments. Aim: This study compared the cyclic fatigue and the canal transportation promotedby TF Adaptive and Navigator EVO systems when used with two different motions. Methods: Forty mesiobuccal roots of maxillary molars were scanned using micro-CT imaging before and after root canal preparation with the two instrument systems two motions (adaptive and continuous rotation). Samples were divided into four groups: TFA – TF Adaptive instruments under adaptive motion; TFC - TF Adaptive instruments under continuous motion; NA - Navigator instruments under adaptive motion; and NC – Navigator instruments under continuous motion. Root canals were prepared until 35.04 instruments. Apical transportation, centering ability and volume were analyzed using micro- CT at three levels: 3, 6 and 9 mm from the apex. The cyclic fatigue tests were performed using a custom-made device. Ten instruments of each brand were activated by using a 6:1 reduction handpiece powered by a torque-controlled motor using the preset programs ‘‘custom mode'' and ‘‘TF Adaptive'' to activate25.06 and 35.04 instruments. Data were analyzed with Kruskal-Wallis and Dunn tests were used to assess canal transportation, centering ability and canal volume. Student-T test was used to evaluate cyclic fatigue (P = .05). Conclusions: Both systems can be used under adaptive or continuous rotation. However; the lifespan of the instruments was higher when used under continuous rotation. Little canal transportation occurred when mesiobuccal root canals from maxillary molars were prepared until 35.04instruments.

Thesis (M. A. Agriculture (Plant Protection)) -- University of Limpopo, 2019 / Potato (Solanum tuberosum L.) is highly susceptible to root-knot (Meloidogyne species) nematodes, with no known nematode resistant genotypes. In Limpopo Province, two cucurbitacin-containing phytonematicides had been researched and developed. The active ingredients of the cucurbitacin-containing phytonematicides are cucurbitacins, which are allelochemicals that could induce phytotoxicity on crops being protected against nematode damage. The objectives of this study were to determine: (1) mean concentration stimulation point (MCSP) of Nemarioc-AL phytonematicide on potato cultivar ꞌMondial G3ꞌ for managing M. javanica and (2) application interval of Nemarioc AL phytonematicide on potato cultivar ꞌMondial G3ꞌ. Sprouted tubers were planted in 10 cm deep/pot with each pot filled with steam-pasteurised soil and Hygromix at 3:1 (v/v) ratio in the field under microplot conditions. After 100% emergence (2 weeks), each plant was inoculated with 5 000 M. javanica eggs and second-stage juveniles (J2). Seven treatments, namely, 0, 2, 4, 8, 16, 32 and 64% Nemarioc-AL phytonematicide were arranged in a randomised complete block design, with 11 replications. In Objective 2, four treatments, namely, 1, 2, 3 and 4 weeks were arranged in randomised complete block design, with 15 replications. Plant variables and nutrient elements were subjected to the Curve-fitting Allelochemical Response Data (CARD) model to generate biological indices used to compute MCSP using the relation MCSP = Dm + Rh/2 and the overall sensitivity value (∑k). The MCSP for plant variables and nutrient elements, were empirically derived as 4.31% and 1.33%, with the ∑k of 18 and 4 units, respectively. Nematode variables and increasing concentrations of Nemarioc-AL phytonematicide exhibited negative quadratic relations where eggs, J2 in soil and roots and total population (Pf) were optimised at xv 14.43, 28.23, 23.30 and 13.55%. To conduct Objective 2 which is application interval, empirically derived MCSP value of 4.31% from Objective 1 was used. Application interval was optimised using the concept of 1, 2, 3, and 4 weeks in weeks-per-month-of-30-days. The application interval of 4.31% was established at 2.43 weeks which translated to 18 days [(2.43 weeks/4 weeks) × 30 days]. All nematode variables in Objective 2 were not significantly different at all intervals. In, conclusion Nemarioc-AL phytonematicide can be used at 4.31% concentration to control nematodes population densities without being phytotoxic to crops at 18 days application interval. / National Research Foundation (NRF) , Agricultural Research Council (ARC) and the Flemish Interuniversity Council of Belgium