Yes / Lake-dwellings in the northern Alpine region are renowned for their extraordinary organic preservation. In addition to organic remains, thousands of ceramic sherds are also recovered. This paper addresses ceramic sherds from the Late Bronze Age site Zürich-Alpenquai, and assesses over 2000 sherds for indications of erosion and abrasion in addition to quantifying sherd size and plotting the spatial distribution of these factors. Recording such wear patterns can provide indications of deposition practices in addition to environmental conditions pre- and post-deposition. In this manner the study of ceramic remains from wetland sites for abrasion can complement environmental studies addressing conditions at the time of artefact deposition, and contribute to discussions of influences for lake-settlement abandonment.

O ensaio de desgaste micro-abrasivo por esfera rotativa vem conquistando elevada aceitação em universidades e centros de pesquisa, sendo amplamente adotado em estudos envolvendo desgaste abrasivo de materiais. Dois modos de desgaste abrasivo podem ser observados neste tipo de ensaio: rolamento resulta quando as partículas abrasivas rolam sobre a superfície do corpo-de-prova, enquanto riscamento é observado quando as partículas abrasivas deslizam sobre o mesmo; o tipo do modo de desgaste abrasivo apresenta uma significante influência sobre o comportamento de um sistema tribológico. Diversos trabalhos envolvendo coeficiente de atrito durante ensaios de desgaste abrasivo estão disponíveis na literatura, mas somente uma pequena parcela dedicaram-se ao estudo do coeficiente de atrito desenvolvido em ensaios de desgaste micro-abrasivo conduzidos por esfera rotativa. Adicionalmente, pesquisas preliminares reportaram que os resultados são dependentes da variação de pressão, ocasionada pela condução de ensaios sob condições de força normal constante. Logo, o propósito desta Tese de Doutorado é pesquisar a relação entre coeficiente de atrito e modos de desgaste abrasivo em ensaios desgaste micro-abrasivo por esfera rotativa, em condições de força normal constante e pressão constante. Ensaios ball-cratering foram conduzidos com esferas de aço AISI 52100 e um corpo-de-prova de aço-ferramenta AISI H10. A pasta abrasiva foi preparada com partículas de carbeto de silício (SiC) preto (tamanho médio de partícula de 3 m) e água destilada. Diferentes valores de força normal constante e pressão constante foram definidos para os experimentos. As forças normal (N) e tangencial (T) foram monitoradas continuamente durante os ensaios e a relação entre T/N foi calculada para fornecer uma indicação do coeficiente de atrito atuante no sistema tribológico esfera / partículas abrasivas / corpo-de-prova. Em todos os casos, análises por Microscopia Óptica das crateras de desgaste revelaram somente a presença de desgaste abrasivo por riscamento. Entretanto, observações mais detalhadas, conduzidas por Microscopia Eletrônica de Varredura, indicaram que diferentes níveis desgaste abrasivo por rolamento atuaram ao longo dos riscos, fenômeno nomeado de micro-rolling abrasion (microrolamento). Além disso, os resultados obtidos mostraram, também, que: i) a distância de deslizamento apresenta significante influência sobre a transição entre os modos de desgaste abrasivo, ii) para os valores de força normal constante e pressão constante adotados, o coeficiente de atrito manteve-se, aproximadamente, na mesma faixa de valores e iii) o coeficiente de atrito é independente da taxa de desgaste. / The micro-scale abrasive wear test by rotative ball has gained large acceptance in universities and research centers, being widely used in studies on the abrasive wear of materials. Two wear modes are usually observed in this type of test: rolling abrasion results when the abrasive particles roll on the surface of the tested specimen, while grooving abrasion is observed when the abrasive particles slide; the type of wear mode has a significant effect on the overall behaviour of a tribological system. Several works on the friction coefficient during abrasive wear tests are available in the literature, but only a few were dedicated to the friction coefficient in micro-abrasive wear tests conducted with rotating ball. Additionally, recent works have identified that results may also be affected by the change in contact pressure that occurs when tests are conducted with constant applied force. Thus, the purpose of this work is to study the relationship between friction coefficient and abrasive wear modes in ball-cratering wear tests conducted at constant normal force and constant pressure. Micro-scale abrasive wear tests were conducted with a ball of AISI 52100 steel and a specimen of AISI H10 tool steel. The abrasive slurry was prepared with black silicon carbide (SiC) particles (average particle size of 3 m) and distilled water. Two constant normal force values and two constant pressure values were selected for the tests. The tangential and normal loads were monitored throughout the tests and their ratio was calculated to provide an indication of the friction coefficient. In all cases, optical microscopy analysis of the worn craters revelated only the presence of grooving abrasion. However, a more detailed analysis conducted by SEM has indicated that different degrees of rolling abrasion have also occurred along the grooves. The results have also shown that: i) the sliding distance presents an important role on the wear mode transition, ii) for the selected values of constant normal force and constant pressure, the friction coefficient presented, approximately, the same range of values and ii) the friction coefficient was independent of the wear rate.

Les mosaïques de paysages dessinées par les cours d’eau sont le fruit de fonctionnements complexes. Ces fonctionnements sont appréhendés à divers échelles spatio-temporelles (e.g, bassin versant, secteurs fonctionnels, macroformes alluviales ou particules sédimentaires) décrites au sein du concept de système fluvial. Le fonctionnement des systèmes fluviaux s’établissent autour d’équilibres sédimentaires mettant en balance les flux liquides et solides. C’est pourquoi, l’état géomorphologique des cours d’eau à charge sédimentaire graveleuse peut être décrit au travers d’un prisme sédimentaire par l’observation de tendances générales à large échelles, de phénomènes plus ou moins localisés tels que l’incision, l’engravement, la migration des formes sédimentaires ou des modifications des propriétés géométriques des particules constituant la charge sédimentaire. Ainsi, la meilleure connaissance du rôle des flux sédimentaires actuels et passés dans l’état géomorphologique pour la prédiction des trajectoires hydrosédimentaires des cours, répond à des objectifs à la fois écologiques (la perméabilité de la nappe d’alluvions et de la zone hyporhéique exercent des fonctions auto-épuratrices (Datry et al., 2008), la faune benthique est la base de la chaîne alimentaire des écosystèmes fluviaux), politiques (liés à la gestion des risques d’inondation et d’érosion des terres ou d’ouvrages d’ingénierie) ou encore philosophiques (quel fonctionnement de référence pour quel système fluvial ? Quelle implication et quel rôle pour l’Homme dans le fonctionnement de ces systèmes anthropisés à divers degrés ?). Aussi, le développement d’outils et de méthodologie(s) pour la caractérisation des flux sédimentaires ou des processus observés en rivières constitue un axe de recherche important en constante émulsion. Les recherches que nous avons engagés sont articulées autour de trois axes interdépendants : (1) les propriétés physiques des particules sédimentaires, (2) leur mobilité et (3) leur transformation par abrasion. Dans le cadre de ce typique, nous avons cherché à lever le doute subsistant concernant le rôle de la fracturation de traceurs naturels (calcaires) équipés de transpondeurs passifs basses fréquences (PIT-tag) et à tester l’intérêt de l’utilisation de galets synthétiques pour la conception de nouveaux traceurs équipés de transpondeurs actifs ultra hautes fréquences (a-UHF). Nous avons ensuite testé le potentiel de ces transpondeurs (a-UHF), dont les caractéristiques d’émission sont mieux adaptées que celles des PIT-tag à l’étude du fonctionnement des macroformes fluviale à l’échelle de tronçons fonctionnels, puis avons développé une méthodologie de recherche en rivière spécifique à ces nouveaux traceurs. Par ailleurs, Nous avons testé la sensibilité à divers paramètres d’entrée d’un programme de calcul d’émoussé de particules sédimentaires grossières, en avons validé son intérêt pour l’analyse (1) des relations entre évolution des indices d’émoussé et abrasion de la masse sédimentaire et (2) du fonctionnement hydrosédimentaire d’un bassin versant et avons formulé les recommandations nécessaires de respecter pour sa bonne utilisation. Enfin, nous avons cherché à comparer les influences respectives de la densité et de la forme des particules sédimentaires pendant leur transport par charriage. Ces résultats soulignent l’influence au moins aussi grande de la forme comparée à la mobilité, sur le déplacement des particules sédimentaires. / The influence of fluvial systems dynamics on riverine landscape patterns is the consequence of complex ecosystem dynamics. These driving factors can be analysed at different spatiotemporal scales of the fluvial system (for example: river basin, functional units, alluvial megaforms or sedimentary particles). The dynamic of fluvial systems depends on the equilibrium between solid and liquid fluids. For this reason, the geomorphological status of watercourses can be described from a sedimentary perspective taking into account general trends at large scale, local characteristics such as incision, aggradation, sedimentary migration or the alteration of particles’ geometrical properties that constitute bed load. Thus, a better understanding of the influence of past and present sedimentary flows on the geomorphological status of watercourses has at the same time an ecological impact (permeability of both the alluvial layer and the hyporheic zone and its self-filtration function (Datry et al., 2008)), a political impact (related to flood management, erosion risks and issues or hydraulic facilities) or even a philosophical issue (what is the appropriate reference for what fluvial system? What is the role of Humanity on these anthropized environments and at what extent?).Thus, the development of methodological tools to characterize sedimentary flows or the observed dynamics on rivers, is considered a major and rising research issue. The research studies described in this thesis are structured in three distinct topics: (1) physical properties of sedimentary particles; (2) their mobility; (3) their transformation as a consequence of abrasion.In this context, we have analysed the relationship between breakage and low recovery rates for natural tracers (limestone pebbles) equipped with low frequency passive transponders (PIT-tag). In addition, we have tested the use of synthetic pebbles to create new tracers equipped with high frequency active transponders (a-UHF), more performant than PIT-tags. Secondly, we have developed a new search and location field methodology specially, adapted to these new transponders. Thirdly, we have tested the sensibility of the toolbox developed by Roussillon et al. (2009), design to measure the roundness of coarse sedimentary particles, to different entry parameters. We have confirmed its interest to (1) analyse the relationship between particles normalized abrasion and its roundness trends; (2) analyse the hydrosedimentary dynamics at a river basin scale. We have included several recommendations to apply this toolbox in the appropriate conditions. Finally, we have performed a comparative analysis between particles’ density and shape and its influence on bedrock transport. These results highlight the significant influence of shape on travelled distance in comparison with density.

O ensaio de desgaste micro-abrasivo por esfera rotativa vem conquistando elevada aceitação em universidades e centros de pesquisa, sendo amplamente adotado em estudos envolvendo desgaste abrasivo de materiais. Dois modos de desgaste abrasivo podem ser observados neste tipo de ensaio: rolamento resulta quando as partículas abrasivas rolam sobre a superfície do corpo-de-prova, enquanto riscamento é observado quando as partículas abrasivas deslizam sobre o mesmo; o tipo do modo de desgaste abrasivo apresenta uma significante influência sobre o comportamento de um sistema tribológico. Diversos trabalhos envolvendo coeficiente de atrito durante ensaios de desgaste abrasivo estão disponíveis na literatura, mas somente uma pequena parcela dedicaram-se ao estudo do coeficiente de atrito desenvolvido em ensaios de desgaste micro-abrasivo conduzidos por esfera rotativa. Adicionalmente, pesquisas preliminares reportaram que os resultados são dependentes da variação de pressão, ocasionada pela condução de ensaios sob condições de força normal constante. Logo, o propósito desta Tese de Doutorado é pesquisar a relação entre coeficiente de atrito e modos de desgaste abrasivo em ensaios desgaste micro-abrasivo por esfera rotativa, em condições de força normal constante e pressão constante. Ensaios ball-cratering foram conduzidos com esferas de aço AISI 52100 e um corpo-de-prova de aço-ferramenta AISI H10. A pasta abrasiva foi preparada com partículas de carbeto de silício (SiC) preto (tamanho médio de partícula de 3 m) e água destilada. Diferentes valores de força normal constante e pressão constante foram definidos para os experimentos. As forças normal (N) e tangencial (T) foram monitoradas continuamente durante os ensaios e a relação entre T/N foi calculada para fornecer uma indicação do coeficiente de atrito atuante no sistema tribológico esfera / partículas abrasivas / corpo-de-prova. Em todos os casos, análises por Microscopia Óptica das crateras de desgaste revelaram somente a presença de desgaste abrasivo por riscamento. Entretanto, observações mais detalhadas, conduzidas por Microscopia Eletrônica de Varredura, indicaram que diferentes níveis desgaste abrasivo por rolamento atuaram ao longo dos riscos, fenômeno nomeado de micro-rolling abrasion (microrolamento). Além disso, os resultados obtidos mostraram, também, que: i) a distância de deslizamento apresenta significante influência sobre a transição entre os modos de desgaste abrasivo, ii) para os valores de força normal constante e pressão constante adotados, o coeficiente de atrito manteve-se, aproximadamente, na mesma faixa de valores e iii) o coeficiente de atrito é independente da taxa de desgaste. / The micro-scale abrasive wear test by rotative ball has gained large acceptance in universities and research centers, being widely used in studies on the abrasive wear of materials. Two wear modes are usually observed in this type of test: rolling abrasion results when the abrasive particles roll on the surface of the tested specimen, while grooving abrasion is observed when the abrasive particles slide; the type of wear mode has a significant effect on the overall behaviour of a tribological system. Several works on the friction coefficient during abrasive wear tests are available in the literature, but only a few were dedicated to the friction coefficient in micro-abrasive wear tests conducted with rotating ball. Additionally, recent works have identified that results may also be affected by the change in contact pressure that occurs when tests are conducted with constant applied force. Thus, the purpose of this work is to study the relationship between friction coefficient and abrasive wear modes in ball-cratering wear tests conducted at constant normal force and constant pressure. Micro-scale abrasive wear tests were conducted with a ball of AISI 52100 steel and a specimen of AISI H10 tool steel. The abrasive slurry was prepared with black silicon carbide (SiC) particles (average particle size of 3 m) and distilled water. Two constant normal force values and two constant pressure values were selected for the tests. The tangential and normal loads were monitored throughout the tests and their ratio was calculated to provide an indication of the friction coefficient. In all cases, optical microscopy analysis of the worn craters revelated only the presence of grooving abrasion. However, a more detailed analysis conducted by SEM has indicated that different degrees of rolling abrasion have also occurred along the grooves. The results have also shown that: i) the sliding distance presents an important role on the wear mode transition, ii) for the selected values of constant normal force and constant pressure, the friction coefficient presented, approximately, the same range of values and ii) the friction coefficient was independent of the wear rate.

La fréquence des opérations de maintenance lors de l’excavation du sol par les tunneliers est problématique pour les entreprises de travaux publics. Ces opérations de maintenance engendrent des temps morts onéreux et nécessitent l'intervention d'opérateurs dans des conditions de travail hyperbares. Une des raisons aux nombreuses interventions humaines pour la maintenance est l’endommagement des outils racleurs du sol excavé (dents) qui sont placés sur la tête du tunnelier. Ces outils sont sujets à l’usure compte tenu de l’abrasivité des différents milieux qu’ils rencontrent. Le but de cette thèse est de contribuer à augmenter d’au moins 20% la durée de vie des matériaux constitutifs de ces outils, afin de réduire les différentes opérations de maintenance qui exposent les opérateurs à des risques importants. Pour atteindre cet objectif, les investigations menées dans ce travail ont porté sur plusieurs axes. Dans un premier temps, une expertise est menée pour identifier les modes d’endommagement prédominants sur les inserts à base de carbure de tungstène placés sur les dents ; ensuite, de nouveaux matériaux avec des propriétés mécaniques et des microstructures optimisées, développés dans le cadre du projet européen NeTTUN, sont caractérisés sur des bancs d’essais représentatifs. Ces essais ont permis de bien comprendre les mécanismes d’usure des nouveaux matériaux à base de carbure de tungstène. Les résultats de ce travail peuvent ensuite donner lieu à de nouvelles orientations en matière de choix de matériaux pour renforcer les dents de tunnelier. / The frequency of maintenance operations during the excavation of the ground by the tunnel boring machines (TBM) is problematic for civil engineering companies. These maintenance operations provoke expensive timeouts and they bring in excavation operators in risky hyperbaric work conditions. One of the reasons which leads to the numerous human interventions for the maintenance is the damage of drag bits located on the cutting wheel of the TBM. These drag bits undergo wear due to the abrasiveness of the various media they meet. The purpose of this thesis is to contribute to increase by 20 % at least the lifetime of the materials of the dag bits, in order to reduce the various maintenance operations which expose the operators to important risks. To achieve this goal, the investigations led in this work concerned several axes. At first, an expertise is led to identify the wear modes prevailing on the carbide inserts located on the drag bits; then, new materials with enhanced mechanical properties and optimized microstructures, developed in the framework of the European project NeTTUN, are characterized on representative lab testing devices. These tests allowed us to understand well the wear mechanisms of the newly developed grades of tungsten carbides. The results of this work can lead to new strategies for the selection of materials to reinforce the drag bits.

Non-exhaust PM10 is an issue in the urban environment linked to health issues. Emissions of non-exhaust PM10 is relatable to pavement properties. Also of importance is resuspension of road dust stored from surfaces. This depends on the traffic and metrological conditions. Given this, the purpose of the thesis was to give an overview limited to Sweden and the Nordic countries regarding non-exhaust PM10 emissions and road dust. The overview includes how particles are related to human health. Also included is the principle of how particles are emitted from road surface and tyre interaction, both directly and through resuspension of road dust. This thesis also includes an overview of how the use of studded tyres impact on asphalt surfacings and how the properties of the materials used impact on the abrasion wear. This is then linked to the emissions of non-exhaust particles. Further described is how measurements can be done of ambient particles and road dust, followed on two major models for road abrasion wear and non-exhaust PM prediction. Also included is how road operation, e.g. traction sanding and dust binding, influence the particle emissions together with other options to reduce the emissions through, e.g. limiting the use of studded tyres. One special issue discussed in this thesis is the lack of holistic view regarding the environmental problems in the urban environment with focus on particle emissions and road noise emissions, both from the road surface and tyre interaction. Currently the most problematic issue is prioritized and the resulting solution to that specific problem might increase other problems. This thesis shows that much knowledge is available regarding non-exhaust PM10 emissions and road dust, but also that several knowledge gaps exists. Several suggestions on further studies is given together with a brief overview on the continued work forward from this thesis. / Icke-avgasemissioner av PM10 är ett problem i urbana miljöer länkat till flera hälsoaspekter. Dessa emissioner kan relateras till beläggningars egenskaper. Även resuspension av vägdamm från ytor är av betydelse och beror på både trafiken och meterologin. Baserat på detta är syftet med denna avhandling att ge en översikt kring icke-avgas PM10 emissioner och vägdamm, begränsat till Sverige och de övriga nordiska länderna. Denna översikt inkluderar hur partiklar relaterar till människans hälsa. Annat som inkluderas är hur partiklarna emitteras från vägyta-däckinteraktionen, både direkt och genom resuspension av vägdamm. Avhandlingen inkluderar även en översikt kring hur användandet av dubbdäck inverkar på vägbeläggningar och hur dess egenskaper inverkar på nötningsslitage. Detta länkas därefter till partikelemissioner. Vidare beskrivs även hur mätningar kan genomföras av partiklar samt vägdamm vilket följs upp av beskrivningar kring två större modeller kring prediktion av nötningsslitage och prediktion av icke-avgasemissioner. Även hur driftåtgärder inverkar på emissionerna tillsammans med alternativ för att minska emissionerna tas upp. Ett särskilt problem som tas upp i avhandlingen är bristen på helhetssyn beträffande miljöproblem i den urbana miljön med fokus på partikel- och bulleremissioner från vägyta-däckinteraktionen. För närvarande brukar det värsta problemet prioriteras och lösningen till det detta problem kan i sin tur medföra att andra miljöproblem istället förvärras. Denna avhandling visar på att mycket kunskap existerar kring icke-avgasemissioner av PM10 och kring vägdamm, men även att flertalet kunskapsluckor existerar. Flertalet förslag på vidare studier ges tillsammans med en överblick kring det fortsatta arbetet. / <p>QC 20180202</p>

Indiana University-Purdue University Indianapolis (IUPUI) / Repair is an alternative treatment option in many cases to replacement of resin matrix composite restoration. However, aged resin matrix composites have a limited number of carbon-carbon double bonds to adhere to a new layer of rein. Therefore, surface treatments of the aged resin matrix composite surface prior to repairing could improve the repair bond strength. The objectives of this study were to: 1) To evaluate various surface treatments on shear bond strength of repair between aged and new microhybrid resin matrix composite, and 2) To assess the influence of applying a silane coupling agent after surface treatments. Eighty disk-shaped resin matrix composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatments (n = 20): 1) Airborne abrasion with 50 μm aluminum oxide, 2) Tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG laser and control group (n = 20). Specimens were cleaned with 35-percent phosphoric acid, rinsed, and dried. Each group was assigned into two subgroups (n =10): a) no silanization, and b) with silanization. Adhesive agent was applied and new resin matrix composite was bonded to each conditioned surface. Bond strength was evaluated by shear test. Data were analyzed with a two-way ANOVA model. The interaction between conditioning and silanization was significant(p = 0.0163), indicating that comparisons of silanization must be evaluated for each conditioning method, and that comparisons of conditioning methods must be evaluated separately with and without silanization. Airborne particle abrasion showed significantly higher repair bond strength than Er,Cr:YSGG laser without silanization (p < 0.0001) and with silanization(p = 0.0002), and higher repair bond strength than the control without silanization (p < 0.00001) and with silanization (p < 0.00001). Airborne particle abrasion did not have significantly different in repair bond strength than Tribosilica coating without silanization (p = 0.70) or with silanization (p = 0.33). Tribosilica coating had significantly higher repair bond strength than Er,CR:YSGG laser without silanization (p < 0.0001) and with silanization (p < 0.0001), and significantly higher repair bond strength than control without silanization (p < 0.0001), but not with silanization (p =0.16). Er,CR:YSGG laser and control did not have significantly different repair bond strength without silanization (p = 1.00) or with silanization (p = 0.11). There was no effect of silanization on repair bond strength overall (p = 0.34) for any of the surface conditioning methods (p = 0.76 for airborne particle abrasion; p = 0.39 for tribosilica coating; p = 1.00 for Er,Cr:YSGG laser, or p = 0.39 for control). Airborne particle abrasion with 50-μm aluminum oxide particle and tribochemical silica coating followed by the application of bonding agent provided the highest shear bond strength values, suggesting that they might be adequate methods to improve the quality of the repairs of resin-matrix composites.

O objetivo do presente estudo foi avaliar as alterações ocorridas na dentina radicular de dentes permanentes provenientes de pessoas submetidas aos diferentes tratamentos antineoplásicos após erosão (in situ), cárie (in situ) e abrasão (in vitro). Foram selecionados dentes extraídos de pacientes que realizaram tratamentos para câncer na região de cabeça e pescoço (CCP) no Hospital das Clínicas de Ribeirão Preto ou no Hospital do Câncer de Barretos Os dentes foram divididos em grupos de acordo com o tratamento antineoplásico: CO- controle: dentes extraídos de pacientes saudáveis; RTX - radioterapia na região de cabeça e pescoço; QTX quimioterapia; QRT quimioradioterapia. Todos os fragmentos de dentina radicular foram aleatoriamente distribuídos entre os voluntários de cada fase. Na primeira fase foi realizada a erosão in situ; na segunda fase foi feito o processo carioso nos substratos dentais in situ e na 3ª fase foi realizado o teste de abrasão por escovação in vitro. As variáveis de resposta quantitativas foram: perfil de desgaste, degrau formado, número, área e perímetro dos túbulos dentinários, rugosidade da superfície, volume perdido e quantificação do tecido desmineralizado; e qualitativamente analisou-se a morfologia da superfície. Na erosão observou-se que o processo erosivo produziu um aumento no número, diâmetro e área dos túbulos de modo geral, sendo que apenas QRT apresentou maior perda estrutural e diferente estatisticamente em relação aos outros grupos (p<0,05). No processo carioso nenhum tratamento proporcionou alteração quantitativa maior que o controle (p>0,05), contudo morfologicamente foi observado que o tecido dentinário submetido à QRT apresentou uma superfície mais amorfa. Na abrasão, o grupo RTX apresentou maior perda estrutural e diferente estatisticamente de todos os grupos (p<0,05), além de morfologicamente apresentar um maior padrão de desgaste. Conclui-se que os tratamentos antineoplásicos alteraram a dentina radicular e afetaram os processos de erosão, cárie e abrasão / The aim of the present study was to evaluate the alterations on root dentin of permanent teeth from individuals submitted to different antineoplastic treatments after erosion (in situ), caries (in situ) and abrasion (in vitro).Teeth extracted from patients who underwent cancer treatments in the head and neck region (HNC) at Hospital das Clínicas de Ribeirão Preto or at Hospital do Câncer de Barretos were selected and divided into groups according to antineoplastic treatment: CO-control: teeth extracted from healthy patients; RTX- radiotherapy in the head and neck region; QTX - chemotherapy; QRT - chemoradiotherapy. All fragments of root dentin were randomly distributed among the volunteers of each stage. In the first phase, erosion was carried out in situ; in the second phase the carious process was performed on the dental substrates in situ and the third phase was performed the in vitro abrasion test by teeth-brushing machine. The quantitative response variables were: wear profile, step, number, area and perimeter of the dentinal tubules, surface roughness, volume loss and quantification of the demineralized tissue; and qualitatively was analyzed the surface morphology. For the erosive process, it was observed an increase in the number, diameter and area of the tubules for all groups, but only QRT presented greater structural loss with statistical difference in relation to the other groups (p <0.05). For the carious process, no treatment provided a quantitative alteration greater than the control (p> 0.05). However, morphologically, it was observed that the dentinal tissue submitted to QRT presented a surface more amorphous. For the abrasion, the RTX group presented higher structural loss and statistically different from the other groups (p <0.05), besides presenting, morphologically, a higher pattern of wear. It was concluded that the antineoplastic treatments changed the root dentin and affected the processes of erosion, caries and abrasion

Este estudo avaliou in situ a ação do gel contendo euclea natalensis na redução da erosão associada ou não abrasão em esmalte e dentina humanos. O estudo foi realizado em duas fases cruzadas de cinco dias cada (SG - sem gel e CG - com gel) nas quais 10 voluntários utilizaram placas palatinas com 4 blocos de esmalte e 4 blocos de dentina, distribuídos em duas fileiras horizontais contendo 4 blocos, correspondendo aos subgrupos: erosão (Eros); erosão + abrasão (30min) (Eros + Abras). Em fases alternadas metade dos voluntários teve a aplicação do gel em todos espécimes do aparelho e na outra metade os espécimes não sofreram tratamento nenhum. O gel foi aplicado durante 5 minutos, sendo o mesmo removido após este tempo. Na etapa experimental os aparelhos foram imersos em refrigerante 4x ao dia, por 5 minutos. A seguir o aparelho foi colocado na boca por 30 minutos. Após este período os voluntários escovaram 4 espécimes da fileira Eros + Abras e recolocaram o aparelho. A outra fileira (Eros) não foi escovada. A análise da perda de estrutura dentária foi realizada por meio de teste de perfilometria e microdureza. Foi utilizada a análise de variância (ANOVA) a 2 critérios (presença ou ausência da aplicação do gel) de acordo com cada substrato e o teste TUCKEY (p<0,05). Não houve associação entre perda de dureza e condições ou grupos testados (p>0,05). O desgaste dentário médio nos blocos de esmalte para o grupo CG foi de 12,86µm eros e 12,13µm eros+abras e para os blocos de dentina foi de 5,95µm eros e 6,16µm eros+abras. A média de desgaste dentário para o grupo SG, em blocos de esmalte foi de 14,08µm eros e 16,29µm eros+abras e, nos blocos de dentina foi de 13,64µm eros e 12,63µm eros+abras. Houve diferença significativa entre os grupos (p<0,05). Concluiu-se que o gel contendo euclea natalensis é capaz de reduzir o desgaste associado ou não a abrasão, independente do tipo de substrato, esmalte ou dentina. / This study investigated the action of in situ gel containing euclea natalensis on reducing erosion associated or not with abrasion in the human enamel and dentin. The study was performed into two phases crossed in five days each (WOG-without gel and WG- with gel) in which ten volunteers used acrylic palatal appliances with four blocks of enamel and four dentin, distributed in two horizontal rows containing four blocks, corresponding to the subgroups: erosion (Eros); erosion + abrasion (30min) (Eros + Abras). In alternating phases half the volunteers had the applying the gel at all specimens. And the other half of the volunteers have not suffered any treatment. The gel was applied during 5 minutes, being removed after this time. In stage experimental, the blocks were subjected to erosion by immersion of the appliances into soft drink for five minutes, 4 times a day. The appliance was then replaced into the mouth for 30 minutes. After this period the volunteers brushed row (eros+abrasion) and replaced into the mouth. The row (eros) was not brushed. The analysis of the dental structure were determined using profilometry and microhardness tests. ANOVA by two criteria (presence or absence of application of gel) in agreement with each the substrate and Tukey test were applied (p <0.05). Microhardness and conditions or groups tested were not found association (p> 0.05). The mean wear in enamel blocks was 12.86µm eros and 12.13µm eros + abras in the WG group and in dentin blocks was 5.95 µm eros and 6.16µm eros+ abras. The mean wear in enamel blocks was 14.08µm eros and 16.29µm eros+abras for the WOG group and in dentin blocks was 13.64µm eros and 12.63µm eros + abras. There was significant difference between groups (p <0.05). It concluded that the gel containing Euclea Natalensis can reduce erosion with or without abrasion, independently of the substrate type, enamel or dentin.

Objetivo: avaliar e comparar os efeitos do jato de óxido de alumínio sobre a superfície do esmalte, quando aplicados por tempos diferentes. Material e métodos: 110 pré-molares foram obtidos por meio de doações do Banco de Dentes da FOUSP. Os dentes foram divididos aleatoriamente em 5 grupos (n=22) para a aplicação de jato de óxido de alumínio por diferentes períodos de tempo. Nos grupos A, B, C, D e E o jato de óxido de alumínio de 50 ?m foi aplicado, respectivamente, por 01, 03, 05, 07 e 10 segundos. Avaliações quantitativas da superfície do esmalte foram realizadas pelas análises das alterações do perfil e da rugosidade (Sa) da superfície vestibular antes e após o seu jateamento, por meio do medidor de perfil Form Talysurf Intra (Taylor Hobson - AMETEK Inc, Pennsylvania) e do interferômetro a laser Talysurf CCl Lite (Taylor Hobson - AMETEK Inc, Pennsylvania), respectivamente. Uma avaliação qualitativa da superfície do esmalte foi realizada por meio da microscopia eletrônica de varredura (MEV). Para esta última análise, um exemplar de cada grupo foi selecionado aleatoriamente para que as superfícies de esmalte jateadas fossem devidamente preparadas para as suas leituras. Os dados quantitativos foram comparados pelo teste ANOVA, seguido do teste post hoc de Tukey, adotando-se um nível de significância de 5% (p= 0,05). Resultados: observou-se maior alteração do perfil e da rugosidade conforme se aumentou o tempo de aplicação do jato de óxido de alumínio. Porém, com relação à alteração do perfil, diferenças estatisticamente significantes foram observadas somente entre o grupo A (1s) quando comparado aos grupos D (7s) e E (10s), e entre o grupo B (3s) quando comparado com o grupo E (10s). Quanto à rugosidade, verificou-se diferença estatisticamente significante apenas entre o grupo E (10s) quando comparado aos demais grupos. As cinco imagens obtidas pelo microscópio eletrônico de varredura (MEV) demonstraram bastante semelhança entre si, com padrão de condicionamento marcado por picos e vales, porém as imagens dos esmaltes jateados por 1 e 3 segundos apresentaram esses picos e vales em menor quantidade. Conclusão: a perda de estrutura dentária e a rugosidade da superfície do esmalte aumentaram conforme se aumentou o tempo de aplicação do jato de óxido de alumínio; a aplicação do jato de óxido de alumínio por 1 e 3 segundos promove menos perda de estrutura de esmalte do que quando se jateia o esmalte por 10 segundos; maior rugosidade pode ser obtida com o jateamento de óxido de alumínio por 10 segundos; entretanto, o aspecto morfológico do esmalte dentário é bastante similar, independentemente do tempo de jateamento. / Objective: To evaluate and compare the effects of aluminium oxide sandblasting on enamel surface when applied at different times. Materials & Methods: 110 premolars were obtained from the local tooth bank. The teeth were randomly divided into 5 groups (n = 22) for application of aluminium oxide sandblasting at different times. In Groups A, B, C, D and E, sandblasting with 50-?m aluminium oxide particles was applied for 01, 03, 05, 07 and 10 seconds, respectively. Quantitative assessments of enamel surface were performed by analysing changes in the profile and roughness (Sa) of the buccal surface before and after sandblasting application by using a profile gauge (Form Talysurf Intra, Taylor Hobson - AMETEK Inc, Pennsylvania, USA) and a laser interferometer (Talysurf CCl Lite, Taylor Hobson - AMETEK Inc, Pennsylvania, USA), respectively. A qualitative assessment of enamel surface was performed by means of scanning electron microscopy (SEM). For this latter analysis, a sample of each group was randomly chosen so that the sandblasted enamel surfaces could be adequately prepared to be evaluated. The quantitative data were compared by using ANOVA test, followed by post-hoc Tukey\'s test, at a significance level of 5% (P = 0.05). Results: Profile and roughness were found to be more altered as the sandblasting application time increased. With regard to the profile, however, statistically significant differences were found only in Group A (1s) compared to Groups D (7s) and E (10s), as well as in Group B (3s) compared to Group E (10s). With regard to the roughness, statistically significant difference was also observed only in Group E (10s) compared to the other groups. Five SEM images were demonstrated to be very similar to each other, with the conditioning pattern being marked by peaks and valleys, although SEM images of enamel blasted for 1 and 3 seconds showed peaks and valleys in lesser amount. Conclusion: Both loss of dental structure and enamel roughness increased as the time for application of aluminum oxide sandblasting also increased; application of aluminum oxide sandblasting for 1 and 3 seconds produced less loss of enamel structure compared to the 10-second application; more roughness can be obtained with application of aluminum oxide sandblasting for 10 seconds; however, the morphological aspect of the tooth enamel is very similar, regardless of the application time.