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Calleberg, Kerstin. "The Victims at Sandby Borg : Tracing mobility and diet usingstrontium analyses". Thesis, Stockholms universitet, Arkeologiska forskningslaboratoriet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170731.
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Sandby borg, an Iron Age ringfort on Öland, Sweden has been and is still at the center of attention in media and archaeological research. The massacre uncovered at the site during recent years opens many doors for analyses on the Migration Period (c. 400-550 AD) Iron Age skeletal remains. Eighteen teeth (molars) from 12 individuals and three rodent teeth were chosen for strontium (87Sr/86Sr) analyses. This was done to establish whether these individuals were locals or non-locals to Öland. The analyses displayed a, for the most part, local 87Sr/86Sr ratio. Two non-locals were identified, as well as a pattern of higher 87Sr/86Sr peaks on numerous of the individuals during a certain age span, which could indicate a local weaning process with a special food.Sandby borg
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Wiener, R. Constance. "Epipathogenesis of caries| Analyses of family structure, fear, and fatalism upon World Health Organization decayed, missing, and filled teeth severity in Appalachia West Virginia and Pennsylvania". Thesis, West Virginia University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3538200.
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Appalachian has many social, economic, and biologic factors impacting dental health over the life-course.
Purpose: This study examined dental caries experience and family structure, dental fear, and fatalism in West Virginia and Pennsylvania.
Method: Using a cross-sectional study design, 2002-2009 Center for Oral Health Research in Appalachia data were analyzed utilizing the World Health Organization definitions for caries experience, dichotomized into low and high. Three groups were studied: 1) children, 11-13 years (N=237); 2) adolescents, 14-17 years (N=191); and 3) adults, 18 years and above (N=1125). For multivariable model development, generalized estimating equations with exchangeable working structures accounted for family clusters.
Results. For children, family (second biological child vs. first biological child and niece/nephew/step-/grandchild/other vs. first biological child) Fatalism Scale, Dental Fear Survey, and Short Form Fear of Pain Questionnaire failed to reach a significant difference with caries experience. There were 38.0% reporting fear on the Dental Fear Survey, and 80.2% on the Short Form Fear of Pain Survey. There were 62.0% reporting fatalism. There were 44.7% first biological children, 32.1% second biological children, and 23.2% with other family relationships.
Overall, for adolescents, family (single parent vs. both parents, same home; and second biological child vs. first biological child and niece/nephew/step-/grandchild/other vs. first biological child) failed to reach a significant difference with caries experience. However, in gender sub-group analysis, living with a single parent was protective for males, with an adjusted odds ratio (AOR) of 0.08 (95% Confidence Interval [CI]: 0.01, 0.42; p = 0.0249). The Fatalism Scale failed to reach a significant difference with caries experience in the overall model. For females, there was an AOR of 6.60 (95% CI: 1.89, 9.64; p = 0.0076). Although the Short Form Fear of Pain Questionnaire failed to reach a significant difference with caries experience in the overall model, for males, the AOR was 12.86 (95% CI: 1.71, 96.59; p = 0.0130) and for females, the AOR was 0.08 (95% CI: 0.01, 0.55; p = 0.100). There were 36.1% reporting fear on the Dental Fear Survey; 63.9% on the Short Form Fear of Pain Survey; and 43.5% reporting fatalism on the Fatalism Scale. There were 54.6% first biological children; 20.6% second biological children, and 24.8% with other family relationships; 53.5% lived in single parent homes.
For adults, a high Dental Fear Survey score was associated with a high caries experience. The AOR was 1.76 (95% CI: 1.29, 2.40; p = .0003). It remained significant for females (AOR= 2.11[95% CI: 1.41, 3.14; p = 0.0003]). For males, those never married, divorced, widowed, separated, or had other living arrangements vs. married/domestic partnering had an AOR of 0.12 (95% CI: 0.04, 0.36; p = .0002).
Conclusion: Caries is a complex disease with many influences. Gender differences exist in age categories in terms of family relationships, fear, and fatalism. Further exploration of these factors is needed to aid in the development of successful interventions to decrease caries severity.
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Hägglund, Eric. "Hogging Wealth : Dental analyses and an interdisciplinary study of the importance of pigs in prehistoric economies". Thesis, Uppsala universitet, Institutionen för arkeologi och antik historia, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324728.
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Studies in zoo-archaeological Neolithic contexts is the study of early animal domestication in relation to humans transitioning into a more sedentary species. Research and documentation are vital for reconstructing the mechanisms behind the threshold event. In this thesis, teeth of Suidae have been documented, analysed and compared osteologically and interpreted cross-culturally. In addition, aDNA, isotope, coat colour and physical mammal size affecting factor studies are presented to contextualise this thesis. Primary osteological methods are Mandibular Wear Stage (MWS), Linear Enamel Hypoplasia (LEH) recordings and lower jaw third molar (M3) length measurement. These methods can detect biometric domestication markers. The analysed Suidae teeth are from the Middle Neolithic site of Ajvide, Gotland, Sweden. A collection of modern wild boar act as Control sample. These teeth are compared primarily with known domestic pig teeth sample statistics from the British Late Neolithic site of Durrington Walls, Wiltshire, United Kingdom. Results indicate that the Middle Neolithic Pitted Ware culture (PWC) on Gotland hunted during winter and kept limited numbers of captive wild boars as totemic animals (pets) possibly bound to land and ancestry. However, an exact reconstruction of the PWC pig pet keeping practices are uncertain due to human-pig relationships being highly dynamic. Intensified pig hunting, not pet keeping should be considered early domestication. Domestication carries with it detectable biometric markers, which seem to be rare in the Neolithic. The cross-cultural comparisons on traditional pig ‘low-intensity husbandry’ can attest to a human-pig relationship of hunter-gatherers keeping captive wild animals. The pig was not a staple food for the PWC and thus not intensively hunted, rather pigs were rare ritualistic commodities and likely highly praised. Perpetuating this human-pig relationship could have been maintained by PWC ‘big men’ that engaged in socio-political lavish giveaways at festivities and funerals, thus ‘hogging wealth’, but never domesticated the pig.Studier i neolitiska zoo-arkeologiska sammanhang är undersökningar av tidig domesticering av djur i förhållande till mänsklighetens övergång till en mer stillasittande art. Forskning och dokumentation är avgörande för att rekonstruera mekanismerna bakom övergången. I denna uppsats har svintänder dokumenterats, analyserats och jämförts osteologiskt och tolkats tvärkulturellt. Studier i aDNA, isotop, pälsfärg och fysiska storleksfaktorer hos däggdjur presenteras också för att kontextualisera denna uppsats. Primära osteologiska metoder är tandslitage i underkäke (MWS), linjär emaljhypoplasi (LEH) och underkäkens tredje molar (M3) mätningar. Dessa metoder kan finna biometriska domesticeringsmarkörer. De analyserade svintänderna kommer ifrån den mellanneolitiska lokalen Ajvide, Eksta socken, Gotland. En samling moderna vildsvin agerar kontrollmaterial. Dessa tänder jämförs i första hand med kända domesticerade stenåldersvin från den Brittiska senneolitiska lokalen Durrington Walls, Wiltshire, Storbritannien. Resultaten indikerar på att den mellanneolitiska gropkeramiska kulturen (GRK), jagade på Gotland under vinterhalvåret och tog tillfånga ett begränsat antal svin som husdjur (totemdjur). Troligen togs svin tillfånga av olika ’hus’ till följd av att svinet var bundet till land och förfäder. En exakt rekonstruktion av GRKs svinhållningspraktik är dock osäkert på grund av att människo-svin relationer är dynamiska. Intensifierad svinjakt, inte tillfångatagandet av enstaka djur bör betraktas som tidig domesticering. Domesticering medför speciella biometriska markörer som är ovanligare i neolitisk tid. De tvärkulturella jämförelserna i traditionell "lågintensiv svinhållning" kan intyga på ett sådant förhållande mellan jägare-samlar grupper och vildsvin. Även om svinet inte var en basföda åt GRK, och därmed inte intensivt jagade, var svinen sällsynta ritualistiska handelsvaror och troligen högt värdesatta. Gropkeramiska "stormän" kan ha varit de drivande bakom denna praktik. Dessa ”stormän” engagerade sig i sociopolitiska aktiviteter, festligheter och begravningar, och därmed hade "hamstrat välstånd", men domesticerade aldrig svinet.
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Franzon, Renata. "Eficácia da remoção parcial de tecido cariado em dentes decíduos : ensaio clínico controlado randomizado". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/143682.
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A remoção parcial de tecido cariado (RPTC) em lesões profundas de cárie em dentes decíduos tem demonstrado excelentes resultados clínicos, radiográficos e microbiológicos. No entanto, o desempenho das restaurações com resina composta em dentes que tiveram esse tratamento ainda merece esclarecimentos. O objetivo desse trabalho foi investigar a taxa de manutenção de restaurações sobre tecido cariado através de uma revisão sistemática de literatura e de um ensaio clínico controlado randomizado. Métodos: Cinquenta e uma crianças de 3 a 8 anos de idade (28 meninos e 23 meninas) portadoras de ao menos um molar com lesão profunda de cárie foram incluídas no estudo. Os dentes foram aleatoriamente divididos de acordo com os seguintes tratamentos: Grupo controle: Remoção total de tecido cariado (RTTC) e teste: Remoção parcial de tecido cariado (RPTC). Nos casos em que ocorreu exposição pulpar foi realizada pulpotomia. Três Odontopediatras realizaram os procedimentos que foram acompanhados em 3, 6,12, 18 e 24 meses. Todos os procedimentos foram realizados sob anestesia local e isolamento absoluto. No início e no final do procedimento as crianças reportaram sua ansiedade através de duas escalas: Venham Picture Test (VPT) e Facial Image Scale (FIS). O comportamento da criança durante o atendimento foi avaliado através da escala de Sarnat. Em todos os momentos experimentais foram avaliados os aspectos clínicos e radiográficos dos tratamentos e as restaurações foram analisadas por um examinador cego e calibrado através do USPHS modificado.Para determinar as taxas de sucesso clínico e radiográfico e das restaurações de resina composta foram geradas curvas de sobrevida com o estimador Kaplan-Meyer. A distribuição dos indivíduos cooperativos e não cooperativos de acordo com diferentes variáveis independentes, assim como as comparações das escalas FIS e VENHAM entre os três tratamentos, foram avaliadas utilizando-se o teste de Qui-quadrado. Resultados: Quarenta e oito crianças e 120 dentes foram incluídos na análise. Dentre as variáveis analisadas, apenas o tempo de atendimento afetou significativamente o comportamento das crianças (p=0,018). No grupo RTTC ocorreram 15 casos de exposição pulpar (27,5%), enquanto que no grupo RPTC apenas 1 caso (2%). As taxas de sucesso clínicoradiográfico após RPTC e RTTC foram 92% e 98%, respectivamente (p=0,14). Foi observada uma tendência a menor taxa de sucesso clínicoradiográfico em cavidades oclusoproximais (92%) em comparação com cavidades oclusais (100%), porém não estatisticamente significante (p=0,08). Não houve diferença significativa entre os operadores. A taxa de sobrevida das restaurações foi de 66%, 85% e 92%, para os grupos RPTC, RTTC e pulpotomia, respectivamente, após 24 meses, (p=0,09). Quando a taxa de sobrevida das restaurações foi avaliada de acordo com o tratamento e o tipo de cavidade, foi observada taxa de sobrevida significativamente menor (p=0,007) para restaurações do tipo oclusoproximais após RPTC (52%).Por outro lado, os maiores percentuais 10 de sobrevida das restaurações foram observados em cavidades oclusais após RPTC (95%). A revisão de literatura demonstrou que o sucesso das restaurações aumenta quanto menor o número de superfícies envolvidas, assim, cavidades classe I apresentaram em torno de 90% de sucesso e diminui para 50% quando mais de uma superfície foi restaurada. Conclusões: As restaurações de resina composta sobre tecido cariado necessitam de proservação em curtos períodos de tempo para manutenção e reparo.Partial caries removal in deep carious lesions of primary teeth has been demonstrated excellent clinical, radiographs and microbiological results. However, the clinical performance of composite resin restorations placed over the demineralized dentin need more information. The objective of this work was to investigate the restoration performance over carious tissue trough a literature systematic review and a randomized controlled clinical trial. Methods: Fifty-one children aged from 3 to 8 years old (28 boys and 23 girls) with, at least, one molar with deep carious lesion were included in this clinical trial. The teeth were randomly divided according to the following treatments: Control group - total caries removal (TCR); and Test - partial caries removal (PCR). In case of pulp exposure during dentinal excavation, pulpotomy was performed. Three Pediatric Dentist made the procedures that were followed-up by 3, 6, 12, 18 and 24 months. All procedures were performed under local anesthesia and rubber dam isolation. At the beginning and right after the procedure the children reported their anxiety through two scales: Venham Picture Test (VPT) and Facial Image Scale (FIS). The children behavior during the attendance was valued through Sarnat scale. During the time course follow-up clinical and radiographic aspects of the treatments were evaluated and the restorations analyzed by a calibrated and blinded examiner through modified USPHS. To determine the clinical and radiographic outcomes of composite restorations the groups were statistically analyzed using Kaplan-Meier survival followed by Log Rank. The distribution of cooperatives and non-cooperatives subjects in accordance with different independent variables as well as FIS and VENHAM comparisons between the tree treatments were availed using Qui-square test. Results: The final sample was comprised by forty-eight children and 120 teeth. Among all the analyzed variables, only the time spent for the procedure significantly affected the children behavior (p=0.018) The total caries removal procedure produced 15 pulp exposures (27.5%), while the same event occurred only in one case for the PCR group (2%). The clinical- radiographic success rate after PCR and TCR were 92% and 98%, respectively (p=0.14). It was observed a tendency to lower clinical-radiographic success rate in oclusoproximal cavities (92%) in comparison with oclusal (100%) but without statistic significance (p=0.08). The restorations survival rate was 66%, 85% and 92% to PCR, TCR and pulpotomy groups, respectively after 24 months follow-up (p=0.09). When the restorations survival rate was evaluated in accordance with type of treatment and the type of cavity was observed a significant lower survival rate (p=0.007) to oclusoproximal restoration after PCR (52%). On the other hand, the highest restorations survival was observed in oclusal cavities with partial caries removal (95%). The literature review shows that success rate increases with the decrease of involved surface at the restoration, thus class I restorations presented around 90% of success and it decreases below to 50% if more than one surface are restored. Conclusions: The composite resin restorations placed over caries tissue need shorter follow-up time to evaluate the necessity of being repaired or replaced.
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Bailey, Lillian Amanda. "The Bolton Analysis revisited". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0005/MQ34333.pdf.
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Lam, Raymond Hiu-wai. "Artificial teeth : dental biofilm analysis on a chip". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62525.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
In this thesis, an "artificial teeth" microfluidic device is developed that provides unprecedented control over the conditions required to simulate the growth of complex dental biofilm. Dental plaque formation is not only a precursor to tooth decay, but also induces more serious systemic health problems such as cardiovascular disease, pre-term labor, and diabetes. Therefore, understanding the conditions promoting colonization and subsequent biofilm development involving complex bacteria coaggregation is particularly important. The requirement of the continuous culture and analysis systems for large quantities of growth media and reagents has pushed the move toward microfluidics - the miniaturization and chip-based control of fluidic operations. Microfluidic oxygenation is necessary to regulate the cellular gas condition of culture medium, especially for mixed population biofilms consisting of both anaerobic and aerobic cell populations. A double-layer gas perfusion network structure fabricated above the cell culture regions is developed for culture oxygenation. Throughout the modeling and analysis of the oxygen transfer in microfluidic oxygenators, design strategies for such devices are proposed for different configurations. Various designs of oxygen-nitrogen mixer networks providing parallel oxygenation with differential or tunable oxygen concentrations are described and verified experimentally to test the corresponding applicability in microbiological culture. The microfluidic "artificial teeth" platform, integrated with the microfluidic oxygenators, functions as an effective and inexpensive analysis tool to dynamically adjust critical growth parameters such as bacteria population, growth medium composition, medium flow rate and dissolved oxygen levels. The first single-chamber "artificial tooth" chip is developed for long-term dental biofilm culture with better medium handling, such as mixing, humidification and automated growth medium replenishment. This device is also compatible with different analysis techniques using optical microscopy in order to determine the biofilm thickness, the ratio between viable and dead cells, and the visualization of spatial distribution of different dental bacteria in the biofilm. Furthermore, the single-chamber design is extended to a device containing up to 128 chambers. This "artificial teeth" chip is developed to achieve high-throughput parallel biofilm culture and analysis with a matrix of different growth conditions that can contribute to the quantitative studies of the physiology of dental biofilms. The artificial teeth device is applied to investigate the response of two key dental bacteria, Streptococci sp. and Fusobacterium nucleatum, in the biofilm under different microenvironments, including their growth under different gas conditions and their adherence properties with different sucrose concentrations. This work demonstrates a successful application of microfluidics to long-term biofilm culture applications.
by Raymond H. W. Lam.
Ph.D.
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Steiner, Alexis K. "3D Digitization and Wear Analysis of Sauropod Teeth". Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1525990888624381.
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Whitenack, Lisa Beth. "The biomechanics and evolution of shark teeth". [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002678.
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Benazzi, Stefano <1977>. "Image analysis in the morphological and morphometric study of teeth". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/326/.
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The subject of this doctoral dissertation concerns the definition of a new methodology for the morphological and morphometric study of fossilized human teeth, and therefore strives to provide a contribution to the reconstruction of human evolutionary history that proposes to extend to the different species of hominid fossils. Standardized investigative methodologies are lacking both regarding the orientation of teeth subject to study and in the analysis that can be carried out on these teeth once they are oriented. The opportunity to standardize a primary analysis methodology is furnished by the study of certain early Neanderthal and preneanderthal molars recovered in two caves in southern Italy [Grotta Taddeo (Taddeo Cave) and Grotta del Poggio (Poggio Cave), near Marina di Camerata, Campania]. To these we can add other molars of Neanderthal and modern man of the upper Paleolithic era, specifically scanned in the paleoanthropology laboratory of the University of Arkansas (Fayetteville, Arkansas, USA), in order to increase the paleoanthropological sample data and thereby make the final results of the analyses more significant. The new analysis methodology is rendered as follows: 1. Standardization of an orientation system for primary molars (superior and inferior), starting from a scan of a sample of 30 molars belonging to modern man (15 M1 inferior and 15 M1 superior), the definition of landmarks, the comparison of various systems and the choice of a system of orientation for each of the two dental typologies. 2. The definition of an analysis procedure that considers only the first 4 millimeters of the dental crown starting from the collar: 5 sections parallel to the plane according to which the tooth has been oriented are carried out, spaced 1 millimeter between them. The intention is to determine a method that allows for the differentiation of fossilized species even in the presence of worn teeth. 3. Results and Conclusions. The new approach to the study of teeth provides a considerable quantity of information that can better be evaluated by increasing the fossil sample data. It has been demonstrated to be a valid tool in evolutionary classification that has allowed (us) to differentiate the Neanderthal sample from that of modern man. In a particular sense the molars of Grotta Taddeo, which up until this point it has not been possible to determine with exactness their species of origin, through the present research they are classified as Neanderthal.
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Sathorn, Chankhrit. "Factors affecting fracture susceptibility of tooth root : a laboratory and finite element analysis (FEA) study /". Connect to thesis, 2004. http://eprints.unimelb.edu.au/archive/00001600.
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Mullen, S. Russell. "Accuracy of performing space analysis using emodels[TM] and plaster models". Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3302.
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Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains vii, 56 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 36-39).
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Abdellatif, Abeer Moustafa. "A study of developmental defects of enamel using clinical indices and image analysis". Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247151.
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Li, Zheng. "Spur gear teeth contact analysis on power-train transmission noise, vibration and harshness". Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/3163/.
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The gear meshing is very complex process as high non-linearity behaviour is involved during the process. Normally most analysis of gear tooth contact is on the basis of a hypothesis that the contacted gear teeth are cantilever beams to obtain the approximate results quickly. However, many important factors have been ignored in simulating gear tooth contact using cantilever beam hypothesis, those factors include tooth profile variations, gear rotation speed and input torque, coefficient of friction and geometry distortion. Many of non-linear responses such as noise, vibration, abrasion and so on make the actual contact process much more complicated than those in the cantilever beam hypothesis although it is a reliable reference for integrated gear performance investigation. The main contribution of this thesis is in the investigation of the typical static and dynamic performances of meshing gears by simulating gears rolling-sliding contact processes using non-linear finite element method. A typical spur gear model has been proposed first for performance analysis and the model with integrated parameters could contribute reliable finite element conditions to simulate actual gear meshing. The bending stress and its resultant stress of contacted teeth with static model and dynamic model have been then simulated and the results can be used to provide information on the contacted teeth stresses distribution. The detailed investigation of transmission error in gear meshing has been carried out to understand harmful noise and vibration of gear set and a micro geometry modification of gear tooth profile has been proposed, i.e. tip relief. The gear contact pressure distributions and transmission errors have been then analyzed with micro geometry modification and the analysis is under static and dynamic boundary conditions. Finally, the most significant contribution of the thesis is the investigation of the frictional effect on dynamic performance, including dynamic stress and transmission errors.
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Meredith, Neil. "An in-vitro analysis of the stresses in natural and restored human teeth". Thesis, University College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286166.
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Tuttle, Kimberly. "An Analysis of California Drug Courts: Why Drug Treatment Programs Should Have Teeth". Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2124.
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Since the passing of Proposition 47 in California in 2014, drug court programs across the state have invariably undergone changes. In my thesis, I evaluate the drug court programs of three counties in Southern California: Orange County, Los Angeles County, and Riverside County. Through a qualitative analysis of the drug court programs in these counties, via interviews, data collection, and courtroom observation, I provide insight into the functionality of each county's program, as well as an analysis of the effects of Proposition 47. This paper aims to address the key factors involved in maintaining a functional and successful drug court system.
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Steward, Julian Holmes. "Elastic analysis of load distribution in wide-faced spur gears". Thesis, University of Newcastle Upon Tyne, 1989. http://hdl.handle.net/10443/804.
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The load distribution across the contact line(s) of spur gears is essential for the gear designer to be able to accurately stress gears for a given application. Existing gear standards (eg BS 436, AGMA 218 DIN 3990) use a thin slice (2D) model of the meshing gear teeth to estimate the contact line load distribution. This approach clearly fails to model properly teeth subjected to mal-distributed loads, since the buttressing effect of adjacent tooth sections tends to flatten the load distribution. Non-linear tooth modifications such as crowning and some forms of lead correction are also inadequately modelled. This thesis sets out the theory for a 3D elastic model of widefaced- spur gears that has been implemented on a micro-computer. The required 3D contact line influence coefficients for standard form zero modification spur gears with 18 to 100 teeth have been determined by Finite Element analysis. These theoretical values have been compared with results from experiments carried out on a complete large module (18. Omm) wide-faced spur gear. The effect of the various elemental gear errors (eg pitch, profile, lead) and profile modifications have been investigated using the 3D computer model; the results compared with results predicted by the existing gear design standards. The existing gear standards use 2D tooth compliance values up to 50% less than those obtained in this work, largely due to inadequate modelling of the gear body compliance, which is most significant in gear wheels. Comparison of 3D tooth compliance values shows a large discrepancy between author's results again due to inadequate modelling of the gear body.
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Fishman, Ross H. "The Molecular Analysis of the Biofilm of Proximal Incipient Caries in Young Permanent Teeth". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244847351.
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Benzahya, Mohamed. "Analysis of the occurrence of taurodontism in patients attending the Tygerberg Oral Health Centre". University of the Western Cape, 2015. http://hdl.handle.net/11394/5038.
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Magister Scientiae Dentium - MSc(Dent)Aim: Analysis of the occurrence of taurodont molars among patients attending the Tygerberg Oral Health Centre. Methodology: A retrospective descriptive study comprising 1608 panoramic radiographs of patient records, 815 females and 793 males, ranging in ages from 18 to 68 years old. The panoramic radiographs were evaluated for presence of taurodontism. Gender predilection and location of taurodont molars were analysed using a chi-square test. Results: Taurodontism was found in 52 (3.23%) radiographs distributed according to gender (30 females and 22 males [P > 0.05]). The overall prevalence of taurodont molars was (0.73%) from a total of 17148 molars that were examined. The mandibular molar teeth were more affected than the maxillary molar teeth and the second mandibular tooth was the most affected. Conclusion: Taurodontism was not uncommon in a group of patients that attended the Tygerberg Oral Health Centre, UWC. Further larger scale studies are required to assess its distribution in the general population of South Africa to compare it with other ethnic groups and to establish any associations. However, taurodontism in mandibular teeth is a condition that should be taken into consideration, especially the second mandibular tooth, to avoid complications.
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Patel, Nirdesh D. "Efficient prediction of bite fracture force for hard food items". Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/theses/228/.
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Schroeder, Agmar Anthony. "Micro-computed tomography analysis of post space preparation in teeth obturated with carrier-based thermoplasticized gutta percha techniques". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51594.
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Many dentists use the obturation technique of carrier-based thermoplasticized gutta percha. Placement of a post may be indicated for teeth in which there has been extensive loss of coronal tooth structure. This study aimed to determine if post space preparation deviated from the endodontic preparation in teeth obturated with the Thermafil, GuttaCore, or gutta percha material. Forty-two extracted human permanent maxillary lateral incisors were decoronated and their root canals instrumented with nickel-titanium rotary files using a standardized protocol. Samples were divided into three groups and filled with Thermafil, GuttaCore, or gutta percha, before post space preparation was performed. Teeth were scanned using micro-computed tomography after obturation, and again after post space preparation. Scans were examined for post space deviation, volume and linear deviation of post space preparation, and minimum root thickness before and after post space preparation. Data were analyzed with parametric and non-parametric statistical methods. Deviation occurred in eight teeth; seven from the Thermafil group (50%), one from the GuttaCore group (7%), and none from the gutta percha group. Deviation occurred statistically more often in the Thermafil group than in each of the other two groups (p < 0.05). The volume difference before and after post space preparation was statistically greater in the Thermafil group than in each of the other two groups (p < 0.05). Linear deviation of post space preparation was greater in the Thermafil group than in both of the other groups, and was statistically greater than that of the gutta percha group (p < 0.05). The minimum root thickness before post space preparation was significantly greater than it was after post space preparation for all groups (p < 0.01). There was no difference between the groups with respect to the difference in minimum root thickness before and after post space preparation. The differences in the number of samples showing post space deviation, volume, and linear deviation of post space preparation amongst the Thermafil, GuttaCore, and gutta percha groups were due to the presence or absence of a carrier as well as the different carrier materials.Dentistry, Faculty of
Graduate
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Scarff, Morgan. "Functional Analysis and Treatment of Bruxism in Children with Autism Spectrum Disorder". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6581.
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Bruxism, the gnashing or grinding of one’s teeth, is a significant dental concern that can lead to severe damage of the tooth and gum structures and has been suggested to occur at higher rates in the developmentally disabled population. Very little research has been conducted in this area and of those articles, none of which utilized function based treatments nor conducted functional analyses. The purpose of this investigation was to examine the effects of a function based stimulation intervention on audible diurnal bruxism with two adolescent boys diagnosed with autism spectrum disorder. Functional analyses were conducted for both participants and revealed that bruxism was exhibited across all conditions and occurred highest in the alone condition, suggesting that the behavior was maintained by automatic reinforcement. Based on these findings, a function based stimulation treatment was developed to examine the effects of auditory and tactile stimuli on bruxism relative to conditions in which no stimuli were available. Results indicated that the function based stimulation intervention produced substantial decreases in bruxism for both participants. A post stimulation evaluation further supported these findings, showing the occurrence of bruxism remained at low levels following the removal of the stimulus, suggesting the application of the stimulation acted as an abolishing operation for bruxism.
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Faulkner, Dennis W. "A view from the teeth in the war of the flea an analysis of U.S. Army tactics in Iraq". Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Dec%5FFaulkner.pdf.
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Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, December 2007.Thesis Advisor(s): Wirtz, James ; Russell, James. "December 2007." Description based on title screen as viewed on January 18, 2008. Includes bibliographical references (p. 77-79). Also available in print.
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Pedrosa, Alexsander Ribeiro. "Análise química e topográfica em superfícies tratadas de implantes osseointegráveis de titânio". CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2011. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=158.
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NenhumaEmbora o titânio e suas ligas sejam amplamente utilizados na implantodontia e os resultados das experiências clínicas comprovarem que estes materiais apresentam excelente biocompatibilidade, existem questionamentos quanto às propriedades físico-químicas ideais das superfícies dos implantes de titânio cppaarrroaap crstieee rdoísabtdtieceras sus musãpaoe roifsmisceipaooiisnr ttdeagnorstae çismã, opu lmaadnaet qevusea zdd aeq ueti etd âuanr iaood soasuienroadi.na t Nenogã roea nçeãtsaotnã otéo ,di neotfsei nnmisdaoomdse enlnoats e l iptdaeerrpaae tnuddreaefi.n ntEiers tdaaass ligação das células com a superfície do implante. A composição química e a topografia da superfície e métodos de subtração e de revestimentos utilizados em modificações de superfícies de titânio comercial implantes dentários foram estudados por espectroscopia de emissão de fotoelétrons por raios-X (XPS), espectroscopia por energia dispersiva (EDS), microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM), e difração de raios X (XRD). As amostras foram dispostas em cinco grupos, de acordo com tratamento de superfície: (1) duplo ataque ácido, (2) anodização e incorporação de Ca/P, (3) condicionamento ácido e deposição de Ca/P, (4) plasma spray de hidroxiapatita, e (5) jateamento de Ca/P mais ataque ácido. As análises através de XPS demonstraram que as concentrações de Ti, O e C na superfície foi diferente entre os grupos, o que pode ser atribuído a diversos processos que foram submetidos ao implante na sua fabricação. Além disso, foi demonstrada a presença dos elementos mencionados pelo fabricante nos grupos 1, 2 e 4, mas a ausência de Ca e P nos grupos 3 e 5, divergindo da informação fornecida pelo fabricante. No entanto, eles foram demonstrados em pequenas quantidades por EDS. A análise da composição de contaminação da superfície por EDS em todos os grupos revelou a presença dos elementos C, Na, Si, Nb, Cl, K, V, Al e Fe, atribuído aos elementos de liga, ao processo de fabricação ou à manipulação dos implantes. A análise por XRD demonstrou além da presença de titânio em todos os grupos, a presença de hidreto de titânio no grupo 1, anatase (TiO2) no grupo 2, e hidroxiapatita sintética no grupo 4. O aspecto topográfico do tratamento abrasivo, erosivo e tratamentos de revestimento foram diferentes para os diferentes tratamentos de superfície, como observado por SEM e AFM. O tratamento abrasivo associado ao erosivo aumentou o parâmetro de rugosidade Sa e o tratamento erosivo sozinho diminuiu o Sa. Os parâmetros Ssk e Ska para as superfícies estudadas variaram os valores entre negativos e positivos, indicando que as superfícies dos grupos 2 e 4 são compostas por uma superfície áspera com perfil aleatório de picos e vales, sendo a prevalência por vales apresentando boa molhabilidade. Na seqüência as superfícies dos grupos 4, 1 e 3, respectivamente apresentaram as mesmas características em menor relevância.
Although titanium and its alloys are widely used in implantology and results of clinical trials demonstrate that these materials show excellent biocompatibility, there are doubts about the ideal physicochemical properties of the titanium implants surfaces to achieve an adequate and lasting osseointegration. However, the ideal parameters to define the titanium surface properties of dental implants are not yet defined in the literature. These features are important, since osseointegration is heavily dependent on the bonding of the cells with the implant surface. The chemical composition and the surface topography of subtractive and coating methods used in surface modifications of commercial titanium dental implants were studied by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The groups were: (1) double acid etching, (2) anodization and incorporation of Ca/P, (3) acid etching and deposition of Ca/P, (4) hydroxyapatite- blasting, and (5) Ca/P-blasting and acid etching. The XPS analysis showed that the concentrations of O, Ti and C on the surface were different between the groups, which can be attributed to the different processes they are subjected to the implants in their manufacture. Analysis by XPS showed the presence of the elements mentioned by the manufacturer in groups 1, 4, and 5, did not reveal the presence of Ca and P in groups 2 and 3, as mentioned by the manufacturer. However, they were demonstrated in very small amounts by EDS. The composition analysis of surface contamination viewed by EDS in all groups revealed the presence of C, Na, Si, Nb, Cl, K, Al and Fe impurities, attributed to the manufacturing process and handling of the implants. The XRD analysis showed the presence of titanium hydride in group 1, the absence of Ca and P in group 2 and V and Al in group 3 (informed by the manufacturers). However, the presence of Al and V in the latter group was confirmed by the EDS analysis, but not the Ca in the former. The topographical aspect of abrasive, erosive and coating treatments were different for the different surface treatments, as observed by SEM and AFM. The abrasive treatment associated with the erosion increased the rugosity parameter Sa and the erosive treatment decreased it. The parameters Ssk and Ska ranged values between negative and positive, indicating that the areas in groups 2 and 4 were composed of a random rough surface with a profile of peaks and valleys, with the prevalence of valleys with good wettability. The surfaces of groups 4, 1, and 3 presented the same characteristics in lesser relevance.
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Ghattas, Lama Elias. "Identifying Prehistoric Origin and Mobility : using Strontium analysis and laser ablation on teeth enamel from Viking Age boat-graves XI and XIII from Tuna in Alsike". Thesis, Stockholms universitet, Arkeologiska forskningslaboratoriet, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-126265.
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The Viking Age cemetery of Tuna in Alsike from the 9th - 11th century AD is located in the eastern part of middle Sweden and contains inhumation boat graves. Here analysis of Strontium isotopes, using laser ablation method on the tooth enamel of the canine and first molar of two individuals buried in boat-graves XI and XIII have been performed. Comparing Strontium isotope evidence with local strontium ratios and variations indicated that at least one individual, the one in boat-grave XIII, were non-local.
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Holobinko, Anastasia. "STABLE ISOTOPE RATIOS AS A PROXY FOR HUMAN GEOGRAPHIC PROVENANCE: BIOGEOGRAPHICAL EVIDENCE FROM THE 2H, 18O, AND 13C SIGNATURES IN MODERN HUMAN TEETH". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1108.
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The positive identification of a decedent is paramount to a forensic investigation in which human remains have been recovered and must be identified. Due to increasing global mobility in the world's populations, it is not inconceivable that an individual might die far away from his or her home. Pinpointing an individual's geographic origin may contribute to definitive forensic identification of contemporary human skeletal remains in cases where dental records and other means of identification are either unavailable to law enforcement personnel or do not yield immediate results. Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well‐recognized and increasingly important method for determining the provenance of human remains, and it has been used successfully in bioarchaeological studies as well as forensic investigations. Both 18O and 2H stable isotope signatures are well established proxies as environmental indicators of climate (temperature) and source water and are therefore considered reliable indicators of geographic life trajectories of animals and humans. Similarly, 13C and 15N abundance data have distinguished dietary preferences in ancient human populations, and have been used to qualify 2H and 18O geolocational data that may be consistent with more than one location. Few if any studies have systematically investigated the multi-isotopic signatures in human tooth enamel and dentin from living individuals. Since 18O abundance values obtained from tooth enamel of late-erupting molars are a source of information on geographic origin of an individual during adolescence when crown formation takes place, it was hypothesized that: 1) the stable isotope abundance of 2H, 18O, and 13C in human tooth enamel and dentin is consistent with self-reported residential history and dietary preferences data, and 2) the isotopic variability evident between individuals with shared residential history and nutrient intake is quantifiable, and indicative of intra-individual variability. Two pilot studies were conducted to: 1) evaluate the feasibility of extracting and measuring the 2H composition of human tooth enamel and its suitability as a proxy for human geographic provenance, and 2) compare the isotopic abundance of isotopic abundance of 2H and 13C in human crown dentin collagen obtained from archaeological and modern teeth with the 18O and 13C isotopic composition of the corresponding tooth enamel carbonate. A protocol for preparing tooth enamel for 2H analysis was successfully devised and implemented; however, no correlation was observed between tooth enamel 2H abundance values as measured plotted against source water 2H abundance values. While unexpectedly low rates of hydrogen exchange within mineral hydroxyl groups were documented, and it was possible to analyze tooth enamel for its 2H isotopic composition, the seemingly fixed nature of 2H abundance in tooth enamel means that the 2H isotopic signature of tooth enamel cannot be used as an indicator of geographic provenance. Conversely, positive correlations between collagen 2H abundance values of primary dentin with 2H abundance values for source water and also with enamel 18O abundance values suggests that primary dentin collagen 2H values are linked to the isotopic composition of source water. Third molar tooth enamel was sampled from 10 living volunteers undergoing routine tooth extractions at University of Toronto affiliated dental clinics in Ontario, Canada. The mixed-sex group of patients was given questionnaires in which they provided detailed residential history and answered questions pertaining to dietary preferences (e.g., vegetarian) prior to donating all four third molars. Enamel was drilled from the crown of two third molars from each subject, chemically cleaned, and subjected to an acid digest before being analyzed for its 18O and 13C composition using Isotope Ratio Mass Spectrometry. Herewith, isotope abundance values are presented using the delta notation as delta values in per mil (‰). Mean d13CVPDB values for all samples ranged from -9.47 ‰ to -11.31 ‰ (pooled mean = -10.37 ‰), which suggested a persistent C4 plant dietary influence at the time the sampled tooth enamel was forming and is consistent with the typical North American diet. While inter-subject variation contributed the largest proportion of total d13C variability, differences were not significant. The pooled mean d18OVSMOW value for enamel samples was 24.39 ‰, while individual subject mean d18OVSMOW values ranged from 23.76 ‰ to 25.18 ‰. Marked offsets (0.01 ‰ - 0.51 ‰) in mean d18OVSMOW values for each pair of third molars were observed. While subject variation was significant (p=0.0034), neither diet nor sex significantly influenced the oxygen (or carbon) isotope data. Following conversion of d18OVSMOW values to d18OPhosphate values, drinking water values were calculated using the Daux et al. (2008) equation, and compared to their corresponding regional estimated annual average d18O values in precipitation retrieved from the Online Isotopes in Precipitation Calculator (OIPC) (Bowen 2014). Despite observed correlations between the drinking water d18OWater values and d18OOIPC values of four subjects, no statistically significant correlations were evident between the two limited data sets. However, when the isotopically similar d18O values of Toronto area residents were averaged and combined with the remaining Canadian data and the 18O data from 5 enamel samples analyzed in the 2H enamel pilot study, strong positive correlations were evident between d18OPhosphate valuesand d18OOIPC values (R2 = 0.87). Moreover, an equally strong linear relationship was observed between modeled annual precipitation 18O and calculated source water 18O (R2 = 0.87). Based on the d2H, d18O, and d13C values measured in tooth enamel and dentin, it is possible to infer and confirm geographic provenance and dietary intake. However, while enamel carbonate d13C values were consistent with self-reported dietary intake information and residential history, as could be expected vegetarians could not be distinguished from those who consumed meat without determining C/N isotopic ratios in dentin collagen. Further, the presence of strong linear relationships between the 18O composition of enamel carbonate and modeled source water 18O in the merged dataset illustrates the importance of considering site-specific isotopic complexities and using multi-isotope data obtained from multiple tissues when investigating the geographic origins of humans in an archaeological or forensic context. It is not possible to quantify intra-individual isotopic variability without sampling from larger, geographically diverse populations and controlling for as many variables as possible. The construction of regional databases containing 18O and 2H isotopic data obtained from a variety of environmental and human and faunal tissue samples, and the application of such data to individual cases in which geographic origins are desired, is recommended provided the following caveats are considered: 1) whenever possible, d18OPhosphate values should be used when comparing d18O values in tooth enamel with those in precipitation in order to avoid the unmitigated error associated with the application of carbonate conversion equations to enamel phosphate d18O data, 2) the continuous consumption of food sourced elsewhere is liable to affect the overall enamel carbonate d18O values, 3) d18O values in precipitation are not inclusive of the variety of postprecipitation and hydrological processes unique to a particular location, nor are they an accurate representation of the isotopically mixed nature of tap water sourced from distant reservoirs. Hence, extrapolations should be made with caution. Enamel sequential microsampling methods may be advisable for narrowing down a geographic timeline if the overlapping of isotopic signals at various points along the tooth’s longitudinal plane can be quantified and validated. While standardization of analytical methodology is critical to appropriate interpretations of the data, stable isotope profiling is not a standalone method and should be used in conjunction with other lines of evidence in determinations of human provenance.
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Vasquez, Anete. "Teacher Efficacy and Student Achievement in Ninth and Tenth Grade Reading: A Multilevel Analysis". [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002601.
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Jeffrey, Amy. "Exploring palaeoaridity using stable oxygen and carbon isotopes in small mammal teeth : a case study from two Late Pleistocene archaeological cave sites in Morocco, North Africa". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:5443f540-1049-4f89-8240-970afd5e59f5.
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Revised chronologies from Moroccan cave sites have raised questions concerning the timing of changes in human cultural behaviour in relation to past climate shifts. However, many of the inferences about past moisture regimes are based on external records. Therefore, this thesis aimed to develop a palaeoclimate record using oxygen and carbon isotope values (d18O and d13C) in Gerbillinae (gerbil) teeth from two Late Pleistocene cave sites, El Harhoura 2 and Taforalt, in Morocco. Since small mammals are not commonly used to construct proxy climate records, a modern isotope study was undertaken in northwestern Africa to understand the influences on the stable isotope composition of small mammal tissues in semi-arid and arid settings. The results from the modern study show that d18O composition of gerbil teeth is strongly correlated with mean annual precipitation (MAP), and therefore in arid settings reflects moisture availability. Predictably, the d13C values of the gerbil teeth reflected C3 and C4 dietary inputs, but arid and mesic sites could not be distinguished because of the high variability displayed in d13C. The d18O isotope-based MAP reconstructions suggest that the Mediterranean coastal region of North Africa did not experience hyper-arid conditions during the Late Pleistocene. The d13C values of the gerbil teeth show that C3 vegetation dominated in the Late Pleistocene, but there was a small amount C4 vegetation present at Taforalt. This indicates that small mammals are extremely sensitive to discreet shifts in past vegetation cover. Both the modern and archaeological studies demonstrated that the isotope values of molars and incisors differed. The results indicate that tooth choice is an important consideration for applications as proxy Quaternary records, but also highlights a new potential means to distinguish seasonal contexts. Comparisons of proxy climate records and cultural sequences at Taforalt and El Harhoura 2 show that Middle Stone Age occupations of both sites occurred during relatively humid and arid climate phases. The transition to the Later Stone Age appears to have taken place during a period of increased aridity, hinting that this cultural transition may be related to changing environmental conditions.
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Chrcanovic, Bruno Ramos. "Tratamentos de superfície aplicados a titânio para uso em implantes odontológicos". CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2012. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=199.
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NenhumaDesde que Brånemark cunhou o termo osseointegração após a sua descoberta acidental em 1962, o uso de implantes osseointegráveis ganhou força e dentre estes, particularmente os implantes dentais, que são hoje o estado da arte para a terapia reabilitadora oral. Esta fixação biológica (osseointegração) é considerada um pré-requisito para próteses implanto-suportadas e para seu sucesso a longo prazo. Vários fatores foram identificados como particularmente importantes para a incorporação do implante no osso, sendo um deles as propriedades da superfície do implante. Tendo em vista esta importância, o presente trabalho tem como objetivo investigar as modificações nas propriedades morfológicas e fisico-químicas da superfície de titânio utilizado na confecção de implantes odontológicos introduzidas após o tratamento por diferentes metodos de acabamento (jateamento, ataque ácido, imersão em solução para incoporação de Ca/P, formação de oxido de titânio nanoestruturado via anodização). Na primeira parte do presente estudo determinaram-se as melhores condições de jateamento para se obter parâmetros de rugosidade adequados. Para isso, foram inseridas três variáveis: pressão do jateamento, granulometria média de partículas de Al2O3, e área de superfície escaneada. Na segunda parte, discos de titânio foram jateados (com a pressão de jateamento determinada a partir da primeira parte) e submetidos a cinco tratamentos ácidos diferentes. Além disso, dois grupos duplicados foram submetidos à imersão em fluido simulado humano (SBF) e em solução supersaturada de calcificação (SCS). Na terceira parte, a fim de determinar a influência do tempo de imersão das amostras em SBF e SCS em suas características superficiais, novos discos de titânio c.p. foram jateadas com partículas de Al2O3 com granulometria média de 250 μm a 4 bar, sem nenhum tipo de tratamento ácido. Na quarta parte do estudo, investigamos a efetividade de um método de eletropolimento de titânio. Na quinta parte do estudo, investigamos a formação de nanoporos de TiO2 em titânio a partir da técnica de anodização. Com base nos resultados, observou-se que nem sempre há um aumento linear nos parâmetros de rugosidade com o aumento da pressão de jateamento, da granulometria média de Al2O3 e com o aumento da área de varredura, embora haja uma tendência. Frente às situações aqui propostas, definimos a amostra jateada a uma pressão de 4 bar com partículas de Al2O3 com granulometria média de 250 μm como apresentando a melhor superfície para uma melhor osseointegração, baseando-se em resultados de rugosidade apresentados na literatura. Dos tratamentos ácidos diferentes aplicados após o jateamento, dois se mostraram eficientes em remover o alumínio da superfície, que apresenta toxicidade tecidual. Um tempo de imersão de 28 dias em SBF produz uma camada de apatita suficiente para encobrir totalmente a superfície de titânio, independente das condições de jateamento ou de tratamento ácido realizadas. A imersão em solução de SCS produziu a deposição de apatitas mais rapidamente do que em amostras submersas em SBF. As condições de eletropolimento aqui estudadas não foram suficientes para produzir uma superfície homogeneamente polida, necessitando-se de mais experimentação variando-se as condições do processo. O processo de anodização de titânio demonstrou que o aumento da tensão aplicada pode vir a aumentar o diâmetro médio dos poros na superfície. Apesar disso, os resultados se apresentaram bastante diferentes de acordo com as condições aplicadas. Assim, pode ser interessante testar os mesmos parâmetros a temperaturas diferentes, uma vez que o aumento de temperatura irá acelerar a taxa de dissolução química do TiO2 formado, podendo dificultar uma formação homogênea de poros por toda a superfície. Além disso, faz-se necessário um estudo de imersão destas amostras após a anodização em soluções ácidas, para que estes nanoporos possam ser revelados por debaixo da camada de excesso de resíduos de TiO2, supondo-se que tenham se formado. Sugere-se também a realização da anodização em soluções eletrólitas menos ácidas já que, de acordo com a literatura, em valores mais altos de pH da solução eletrolítica o ataque químico à camada de TiO2 é drasticamente mais lento do que em eletrólitos mais ácidos.
Since Brånemark coined the term osseointegration after its accidental discovery in 1962, the use of osseointegrated implants has gained strength, particularly the dental implants, which are now the state of the art for oral rehabilitation therapy. This biological fixation (osseointegration) is considered a prerequisite for implant-supported prostheses and for their long term success. Several factors were identified as particularly important for the incorporation of implant in the bone, one being the properties of the implant surface. Given this importance, this study aims to investigate the changes in morphological and physico-chemical properties of titanium surfaces used in the manufacture of dental implants introduced after treatment by different methods of finishing (sandblasting, acid etching, immersion in solutions for the incorporation of Ca/P, formation of nanostructured titanium oxide via anodization). The first part of the study tried to determine the sandblasting conditions that provided the highest values of roughness parameters, varying the sandblasting pressure, the average particle size of Al2O3 powder, and the scanned surface area. In the second part, titanium disks were sandblasted and subjected to five different acid treatments. Furthermore, two duplicate groups were submitted to immersion in fluid simulated human (SBF) and in solution supersaturated calcification (SCS). In the third part, in order to determine the influence of immersion time of the samples in SBF and SCS in their surface features, new titanium discs were sandblasted with Al2O3 (250 μm 4 bar) without any acid treatment. In the fourth part of the study, we investigated the effectiveness of a method for electropolishing of titanium. In the fifth part of the study, we investigated the formation of TiO2 nanotubes from titanium anodization technique. Based on the results, it was observed that there is not always a linear increase in roughness parameters with increasing sandblasting pressure, average grain size of Al2O3 and with increasing scanning area, although there is a trend. We have defined the sample sandblasted at a pressure of 4 bar with Al2O3 powder with an average particle size of 250 μm as presenting the best surface for a better osseointegration, based on roughness results presented in the literature. Two of the five acid treatments applied after the sandblasting were efficient in removing the aluminum from the surface. An immersion period of 28 days in SBF produces a layer of apatite thick enough to totally cover the titanium surface, independent of sandblasting or acid treatment performed. The immersion in SCS solution produced the deposition of apatites faster than in the samples submerged in SBF. The electropolishing conditions studied here were not sufficient to produce a homogeneously polished surface. Thus, more experimentation varying the process conditions is required. The titanium anodizing process showed that the increase of the applied voltage can produce an increase in the average pore diameter on the surface. Notwithstanding, the anodization results presented quite different from one sample to another. So it may be interesting to test the parameters with different temperatures, since the temperature increase may accelerate the dissolution rate of the TiO2 formed, being able to hamper a homogeneous formation of pores throughout the surface. Furthermore, it is necessary to study these samples after anodization by immersion in acidic solutions, so that these nanopores can be revealed beneath the excess layer of TiO2, assuming that it has been formed. It is also suggested the realization of anodization with less acidic electrolytic solutions since, according to the literature, in higher values of pH of the electrolyte solution etching of the TiO2 layer is dramatically slower than in more acidic electrolyte.
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Leder, Ronny Maik. "Morphometrische Analyse der Kieferbezahnung fossiler wie rezenter carcharhinider Selachier". Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-160324.
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Die morphologische Variabilität dentaler Strukturen, bei Haien der Familie der Carcharhinidae, ist sowohl innerhalb als auch zwischen den Arten unzureichend erforscht. Ohne Kenntnis der artspezifischen Parameter ist eine genaue taxonomische Klassifizierung von fossilen Haien anhand der Zähne jedoch unmöglich. Die umfassende Analyse der dentalen Strukturen rezenter carcharhinider Haie nach artspezifischen Merkmalen wurde genutzt, um die Ergebnisse auf die nächsten fossilen Verwandten zu übertragen. Besonderes Augenmerk galt darüber hinaus dem morphologischen Vergleich fossiler Zähne westatlantischer und zentralasiatischer Herkunft. Es wurde ein morphometrisches Analyseverfahren entwickelt, dass entgegen bestehender Methoden, gänzlich auf manuelle Datengewinnung verzichtet. Für die neue Methode der automatisierten algorithmischen Morphometrie (AAM) wurden erstmals, anhand von 2340 Einzelzähnen von 112 Individuen aus 41 Arten rezenter Carcharhinidae, die wesentlichen artspezifischen Merkmalskomplexe definiert und in ein Analyseprogramm samt Datenbank übertragen. Die Einzeluntersuchung der einzelnen Spezies nach Gesichtspunkten ontogenetischer, sexueller bzw. mono-/dignather Heterodontie sowie intra- und interspezifischer Varianz der Zahnmorphologie zeigte, dass carcharhinide Haie allein mit Hilfe zahnmorphologischer Merkmale identifiziert werden können und diese Merkmale für systematische Zwecke geeignet sind. Der Erfolg der systematischen Zuordnung steht aber in direkter Abhängigkeit zur Zahnposition und zur betrachteten Spezies. Der Einfluss der Heterodontie auf die taxonomische Aussagekraft ist mitunter enorm, so dass die Eindeutigkeit der taxonomischen Klassifizierung stark begrenzt wird. Es existiert eine enorme Bandbreite an morphologischen Überschneidungen und Durchdringungen, sowohl innerhalb der Arten als auch art- bzw. gattungsübergreifend. Beim Vergleich allein anhand einzelner Zähne, sowohl fossiler als auch rezenter Herkunft, ist es in vielen Fällen nicht feststellbar, ob noch innerartliche Varianz oder bereits artliche Differenz vorliegt. Aus den Erkenntnissen der morphometrischen Analyse und deren Übertragung auf die fossilen Belege, ergab sich die Notwendigkeit, fossile Zähne carcharhinider Haie zukünftig, neben dem bestehenden deskriptiven Verfahren der Taxonomie, zusätzlich funktionsmorphologisch zu beurteilen. Dazu wurden erstmals sechs funktionsmorphologische Gruppen definiert, mit deren Hilfe vor allem ökologische Schlussfolgerungen bei der Bewertung fossiler Zähne möglich sindThe morphological variability of dental structures within the different species as well as between the species of sharks belonging to the family of the Carcharhinidae is insufficient investigated. Without knowledge of the species specific parameter the precise taxonomic classification based on the teeth morphology of fossil sharks is kind of impossible. The comprehensive analysis of dental structures of extant carcharhinid sharks was used to transfer the results to their next extinct relatives. Special attention was focused on the comparison between fossil teeth of populations with westatlantic and centralasiatic origin. A morphometric analysis program was established, that is in contrast to traditional methods not based on manual data collection. With the new method of automatic algorithmic morphometry (AAM) the essential species specific attribut complexes were defined for the first time by using the morphological data of 2340 single tooth from 112 individuals from 41 species of extant carcharhinid sharks and transfered to an appropriate new analysis program including all datasets in one database. Individual studies for each single species in aspects like ontogenetic, sexual, mono- and dignatic heterodondity as well as intra- and interspecific variance in tooth morphology proved the possibility to identify carcharhinid sharks just by their teeth and that these attributes can be used for systematic purposes. The effectiveness of the systematic classification stands in direct dependence to tooth position and investigated species. The heterodondity influence for the taxonomic significance is quite high and limiting the taxonomic classification. An enormous bandwith in morphological overlapping and interpenetration is existing as well as within the species but also between species respectively across genus. The comparison based on single teeth with both fossil and extant origin, makes it in many cases impossible to differentiate between intraspecific variance and already existing specific difference. From the new insight to morphological differentiation based on the morphometric analysis (AAM) established in this work and the tranfer from this informations to fossil samples the need for different view to fossil teeth of carcharhinid sharks was obvious. Beside the traditional descriptive procedure of taxonomy a method based on functional morphology is need to better reassess fossil carcharhinid shark teeth. Therefor six functional morphological groups where defined for the first time especially for paleoecological conclusions in the assessment of fossil teeth
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Castro, Waleska. "Elemental Analysis of Biological Matrices by Laser Ablation High Resolution Inductively Coupled Plasma Mass Spectrometry (LA-HR-ICP-MS) and High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS)". FIU Digital Commons, 2008. http://digitalcommons.fiu.edu/etd/185.
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The need for elemental analysis of biological matrices such as bone, teeth, and plant matter for sourcing purposes has emerged within the forensic and geochemical laboratories. Trace elemental analyses for the comparison of aterials such as glass by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS has been shown to offer a high degree of discrimination between different manufacturing sources. Unit resolution ICP-MS instruments may suffer from some polyatomic interferences including 40Ar16O+, 40Ar16O1H+, and 40Ca16O+ that affect iron measurement at trace levels. Iron is an important element in the analysis of glass and also of interest for the analysis of several biological matrices. A comparison of the nalytical performance of two different ICP-MS systems for iron analysis in glass for determining the method detection limits (MDLs), accuracy, and precision of the measurement is presented. Acid digestion and laser ablation methods are also compared. Iron polyatomic interferences were reduced or resolved by using dynamic reaction cell and high resolution ICP-MS. MDLs as low as 0.03 ìg g-1 and 0.14 ìg g-1 for laser ablation and solution based analyses respectively were achieved. The use of helium as a carrier gas demonstrated improvement in the detection limits of both iron isotopes (56Fe and 57Fe) in medium resolution for the HR-ICP-MS and with a dynamic reaction cell (DRC) coupled to a quadrupole ICP-MS system. The development and application of robust analytical methods for the quantification of trace elements in biological matrices has lead to a better understanding of the potential utility of these measurements in forensic chemical analyses. Standard reference materials (SRMs) were used in the development of an analytical method using HR-ICP-MS and LA-HR-ICP-MS that was subsequently applied on the analysis of real samples. Bone, teeth and ashed marijuana samples were analyzed with the developed method. Elemental analysis of bone samples from 12 different individuals provided discrimination between individuals, when femur and humerus bones were considered separately. Discrimination of 14 teeth samples based on elemental composition was achieved with the exception of one case where samples from the same individual were not associated with each other. The discrimination of 49 different ashed plant (cannabis)samples was achieved using the developed method.
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CAMPOS, LUIZA M. de P. "Estudo da aplicação de argilas nanoestruturadas em resinas restauradoras fotoativadas, utilizadas em odontologia". reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10173.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Taylor, Roberta E. "Being clouds, pulling teeth and using their breadloaves : a multimodal micro-analysis of instantiations of child-to-child interaction in classroom contexts". Thesis, University of Sheffield, 2011. http://etheses.whiterose.ac.uk/14655/.
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This study examines the ways in which children communicate and collaborate with one another whilst working on curriculum tasks in an educational setting. It uses an approach to methodology founded on Linguistic Anthropology and Linguistic Ethnography and informed by a social-semiotic theory of communication, drawing upon field notes and video-recorded data from a class of nine and ten year olds at a Sheffield primary school. A framework informed by sociolinguistic theory and multimodal analyses of communication has been devised to analyse the data in such a way that the many and varied modes of meaning-making employed by the children are considered. The purpose of the study is to gain a deeper understanding of the ways in which children creatively employ semiotic resources in their face-to-face spontaneous interactions. The main findings of the study are that modes of meaning-making are integral to the communicative activity and work in coordination with each other. Features which have been noted in linguistic studies of interaction can be seen in this multimodal study and could be classed as features of multimodal communication rather than linguistic features. In addition, child-to-child classroom meaning-making is intersubjective and collaborative. Knowledge can be presented through any chosen mode and can be developed collaboratively through multiple modes. The study has implications for pedagogy in that educationalists need to be aware of the multimodal nature of children's interactions, recognise the value of the semiotic work of pupils and ensure opportunities for meaning-making using multiple modes are planned for. The implications for future research are that methodological approaches need to take account of the use of all modes in interactions in order to gain a thicker description of what is taking place than could be achieved with a language-dominant approach.
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Brasier, Terry Gale. "The Effects of Parental Involvement on Students' Eighth and Tenth Grade College Aspirations: A Comparative Analysis". NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-01152008-152426/.
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Following scholarly calls (e.g., Crosnoe, 2001; Perna & Titus, 2005) for studies related to studentsâ academic trajectories, the purpose of this study was to examine whether the relationship between studentsâ college aspirations and parental involvement differs between the eighth grade and tenth grade years, two critical time periods during which students typically initiate and subsequently reassess future college plans. Utilizing base-year and first follow-up data from the restricted-use version of the National Educational Longitudinal Survey (NELS: 88/90), results from fixed-effects logistic regression analyses indicated that parental involvement has a significant positive effect on the likelihood of students having high college aspirations (desire to finish college) during both the eighth and tenth grade years. Additionally, a cross-model hypothesis test indicated that the magnitude of the relationship between students' college aspirations and parental involvement is significantly weaker during the tenth grade year. In conclusion, findings from this study provide statistical support for previous claims that the relationship between college aspirations and parental involvement weakens as students ascend through the educational pipeline. Results from this study imply that scholars should view the relationship between studentsâ college aspirations and parental involvement as dynamic, rather than static, as students ascend through the secondary school grades and, coincidentally, the student college choice process. Additionally, this studyâs findings imply that future revisions to federal, state, and school-level parental involvement policies such as Section 1118 of the No Child Left Behind Act of 2001 should emphasize proactive forms of parental involvement (e.g., participation in school activities, school-related discussions with students), in addition to motivational forms of parental involvement (e.g., expressed levels of encouragement and expectations for educational attainment), throughout the secondary school years.
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Voth, Christine Bobbitt. "An analysis of the tenth-century Anglo-Saxon manuscript London, British Library, Royal 12. D. xvii". Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708953.
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Ruta, Giancarlo. "Understanding hunter-gatherers behaviour through the macro-fractures analysis of lithic backed points". Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/671946.
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La aplicació d'una metodologia sòlida és premissa fonamental per obtenir informació fiable en cada investigació científica, i particularment en arqueologia prehistòrica, on fàcilment es cometen errors en nivell interpretatiu.
L'objectiu principal d'aquest treball és comprendre la tasca dels caçadors-recol·lectors després l'Últim Màxim Glacial i durant el Tardìoglacial en una àrea determinada a través de l'anàlisi funcional dels materials lítics arqueològics per tal d'aportar una primera presa de contacte a el paper que van desenvolupar els jaciments en un període de canvis climàtics i mediambientals ràpids. Els jaciments de cultura Epigravettiana de Grotta di Pozzo al centre d'Itàlia i Riparo Villabruna al nord han investigat en profunditat des de la perspectiva lítica per identificar possibles puntes de projectil utilitzades durant activitats de caça. Això ofereix una informació detallada sobre tecnologies d'empunyadura i tècniques de caça, brindant un ampli marc dels coneixements i les habilitats pràctiques de la població.
El projecte de recerca introdueix aspectes únics que mai abans havien estat investigats en els jaciments prèviament esmentats. L'adopció sistemàtica de l'arqueologia experimental és innovadora, i s'han provat aspectes específics i majoritàriament desconeguts sobre l'ús d'eines lítiques.
Les dades provinents de l'àmplia literatura i els resultats inesperats es creuen per comprendre les estratègies de caça, el comportament, els desplaçaments, els assentaments estacionals i la possible interrelació entre grups humans en aquesta gran àrea de centre-nord d'Itàlia a la fi de l'Plistocè.La aplicatión de una metodología sólida es premisa fundamental para obtener información fiable en cada investigación científica, y particularmente en arqueología prehistórica, donde fácilmente se cometen errores a nivel interpretativo. El objetivo principal de este trabajo es comprender la labor de los cazadores-recolectores tras el Último Máximo Glacial y durante el Tardìoglacial en un área determinada a través del análisis funcional de los materiales líticos arqueológicos con el fin de aportar una primera mirada al papel que jugaron los yacimientos en un período de rápidos cambios climáticos y medioambientales. Los yacimientos de cultura Epigravettiana de Grotta di Pozzo en el centro de Italia y Riparo Villabruna al norte han investigado en profundidad desde la perspectiva lítica para identificar posibles puntas de proyectil utilizadas durante actividades de caza. Esto ofrece una detallada información sobre tecnologías de empuñadura y técnicas de caza, brindando un amplio marco de conocimientos y habilidades prácticas de la población. El proyecto de investigación introduce aspectos únicos que nunca antes han sido investigados para los yacimientos mencionados. La adopción sistemática de la arqueología experimental es innovadora, y se han probado aspectos específicos y en su mayoría desconocidos sobre el uso de herramientas líticas. Los datos provenientes de la amplia literatura y los resultados inesperados se cruzan para comprender las estrategias de caza, el comportamiento, los desplazamientos, los asentamientos estacionales y la posible interrelación entre grupos humanos en esta gran área del centro-norte de Italia a finales del Pleistoceno.
The application of a robust methodology is a fundamental precondition to get reliable information in every scientific investigation, in particular in prehistoric archaeology where it is easy to make mistakes on the interpretation level. The main goal of this work is to understand the role of the hunter-gatherers after the Last Glacial Maximum and during the Late Glacial in a given area, through the functional analysis of the archaeological lithic materials, in order to give a glimpse of the function of the sites in a period of rapid climate and environmental changes. The Epigravettian sites of Grotta di Pozzo in the Central Italy and Riparo Villabruna in the North Italy have been investigated on the lithic point of view, as to individuate possible projectile points used during hunting activity. This contribution offers detailed information about hafting technologies and hunting techniques, giving a wide framework of knowledge and practical skills of the inhabitants. The research project introduces unique aspects that have never been investigated before for the considered sites. The systematic adoption of the experimental archaeology is innovative, and there have been tested specific and mostly unknown aspects about the use of lithic tools. The data coming from the large literature and the unexpected results are crossed together as to understand the hunting strategies, the behaviour, the movements, the seasonal settlements and the possible connection between human groups in this large area of North-Central Italy at the end of Pleistocene.
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PEREIRA, ANDREA A. "Alteracoes quimicas e fisicas de tecidos duros irradiados por laser de neodimio chaveado". reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11216.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:00/07378-9
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ADACHI, LENA K. "Estudo in vitro do desgaste do esmalte dental pelos materiais restauradores utilizando metodo radiometrico". reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10811.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao [Mestrado]
IEA/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:98/01953-0
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Sommer, Andrew Patrick. "VIBRATION-BASED HEALTH MONITORING OF MULTIPLE-STAGE GEAR TRAIN AND DIFFERENTIAL PLANETARY TRANSMISSION INVOLVING TEETH DAMAGE AND BACKLASH NONLINEARITY". DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/631.
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The objective of this thesis is to develop vibration-based fault detection strategies for on-line condition monitoring of gear transmission systems. The study divides the thesis into three sections. First of all, the local stresses created by a root fatigue crack on a pinion spur gear are analyzed using a quasi-static finite element model and non-linear contact mechanics simulation. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. The second section is dedicated to fixed axis power trains. Torsional vibration is shown to cause teeth separation and double-sided impacts in unloaded and lightly loaded gearing drives. The transient and steady-state dynamic loading on teeth within a two stage crank-slider mechanism arising from backlash and geometric manufacturing errors is investigated by utilizing a non-linear multi-body dynamics software model. The multi-body model drastically reduces the computation time required by finite element methods to simulate realistic operation. The gears are considered rigid with elastic contact surfaces defined by a penalty based non-linear contact formulation. The third section examines a practical differential planetary transmission which combines two inputs and one output. Planetary gears with only backlash errors are compared to those containing both backlash and tooth defects under different kinematic and loading conditions. Fast Fourier Transform (FFT) analysis shows the appearance of side band modulations and harmonics of the gear mesh frequency. A joint time-frequency analysis (JTFA) during start-up reveals the unique vibration patterns for fixed axis gear train and differential planetary gear, respectively, when the contact forces increase during acceleration.
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Lee, Karen Mary. "Inductively coupled plasma-mass spectrometry (ICP-MS) for the analysis of heavy metals in teeth and their use as bio-markers of environmental exposure". Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367153.
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Grimes, V. H. "Oxygen isotope analysis of biogenic phosphate in mammalian bone and teeth : investigating sample pretreatment methodology and intra-species biological variation on oxygen isotope-based palaeoclimate reconstructions during the British Middle to Late Pleistocene". Thesis, University of Bradford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.644723.
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BACHMANN, LUCIANO. "Estrutura e composicao do esmalte e da dentina tratados termicamente ou irradiados com lasers emissores no infravermelho". reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11179.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese(Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:00/01102-1
42
Garcia, Roberta. "Tratamento de lesões profundas de cárie : um ensaio clínico randomizado comparando tratamento expectante com remoção parcial da dentina". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/52449.
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Este ensaio clínico randomizado multicêntrico avaliou a efetividade de um tratamento alternativo em lesões de cárie profundas comparado ao tratamento expectante (TE) após três anos de acompanhamento. O tratamento alternativo consistiu na remoção parcial de tecido cariado (RPTC) seguida de restauração em uma sessão. Métodos: Os critérios de inclusão foram: pacientes com molares permanentes apresentando lesões profundas de cárie (lesão alcançando metade interna de dentina ao exame radiográfico); resposta positiva ao teste térmico; ausência de dor espontânea; sensibilidade negativa à percussão vertical e ausência de lesão periapical detectada no exame radiográfico. Dentes elegíveis para participação no estudo foram randomicamente designados ao grupo teste (RPTC) e receberam remoção incompleta de tecido cariado e restauração em uma sessão (resina ou amálgama). Dentes designados ao grupo controle (TE) receberam capeamento pulpar indireto com cimento de hidróxido de cálcio e restauração temporária com cimento de óxido de zinco e eugenol modificado. Após 60 dias, as cavidades foram reabertas, o tecido cariado remanescente foi removido e os dentes foram restaurados com resina composta ou amálgama. O desfecho avaliado foi a vitalidade pulpar, determinada por sensibilidade ao teste térmico e ausência de alteração periapical ao exame radiográfico. Os dados foram submetidos à análise de sobrevivência (Kaplan Meier), teste Log Rank e análise de regressão de Cox. Resultados: Foram executados 299 tratamentos, sendo 152 RPTC e 147 TE, em pacientes com idade variando entre seis a 53 anos. Até o terceiro ano de seguimento, 209 dentes foram avaliados. Foram observadas taxas de sucesso de 94% para o grupo RPTC e de 78% para o TE (p<0,000). As razões de falha foram: pulpite (4) e necrose (1) no grupo RPTC, e pulpite (11), necrose (5) exposição pulpar seguida de tratamento endodôntico (2), osteíte (1), exodontia (1) e fratura do dente (1) no grupo TE. Variáveis associadas com sucesso do tratamento foram o tipo de tratamento (RPTC) e número de superfícies envolvidas na restauração – uma superfície mais favorável do que duas ou mais superfícies. Os resultados sugerem que não há necessidade de reabrir a cavidade e realizar uma segunda escavação de tecido cariado para preservar a vitalidade pulpar.This randomized multicenter clinical trial evaluated the effectiveness of an alternative treatment on deep caries lesion’s compared to stepwise excavation (SW) after three years follow up. Treatment consisted on partial caries removal (PDR) followed by tooth’s restoration in one session. Methods: Inclusion criteria were: patients with permanent molars presenting deep carious lesions (lesion reaching inner half dentin on the radiographic examination); positive response to cold test; absence of spontaneous pain; negative sensitivity to percussion and absence of periapical lesion detected on radiographic exam. Teeth randomly assigned to PDR (test) received incomplete caries removal and filling in one session (resin or amalgam). Teeth assigned to SW (control) received indirect pulp capping with calcium hydroxide cement, temporary filling with a modified zinc oxide-eugenol cement. After 60 days the cavity was reopened, the remaining decayed dentine was removed and teeth were filled with composite resin or amalgam. Outcome evaluated was pulp vitality, determine by sensitivity to cold test and the absence of periapical alterations on radiographic exam. Data were submitted to Kaplan Meier, log rank test and Cox regression analysis. Results: At baseline, 299 treatments were executed, 152 PDR and 147 SW. At three years follow up, 209 teeth had been evaluated. A success rate of 94% for PDR and 78% for SW was demonstrated (p<0.000). Failure reasons were: pulpitis (4), pulp necrosis (1) for PDR group, and pulpitis (11), necrosis (5), pulp exposure followed by endodontic treatment (2), osteitis (1), tooth extraction (1) and tooth fracture (1) for SW. Variables associated with treatment success were type of treatment (PDR) and number of surfaces involved in the restoration – one surface more favorable than 2 or more surfaces. Results suggest that there is no need to reopen cavity and perform a second excavation to preserve pulp vitality.
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Nettleton, Sarah. "Power knowledge and the production of dentistry : an analysis of the mouth and teeth as the objects and effects of dental practices between 1850 and the present day". Thesis, University of London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297455.
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Macho, Gabriele A., D. Shimizu y I. R. Spears. "The effect of prism orientation and loading direction on contact stresses in prismatic enamel: implications for interpreting wear patterns". 2005. http://hdl.handle.net/10454/3551.
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NoThe ability of prisms to effectively dissipate contact stress at the surface will influence wear rates in teeth. The aim of this investigation was to begin to quantify the effect of prism orientation on surface stresses. Seven finite element models of enamel microstructure were created, each model differing in the angulation of prism orientation with regard to the wear surface. For validation purposes, the mechanical behavior of the model was compared with published experimental data. In order to test the enamel under lateral loads, a compressed food particle was dragged across the surface from the dentino-enamel junction (DEJ) towards the outer enamel surface (OES). Under these conditions, tensile stresses in the enamel model increased with increases in the coefficient of friction. More importantly, stresses were found to be lowest in models in which the prisms approach the surface at lower angles (i.e., more obliquely cut prisms), and highest when the prisms approached the surface at 60° (i.e., less obliquely cut). Finally, the direction of travel of the simulated food particle was reversed, allowing comparison of the difference in behavior between trailing and leading edge enamels (i.e., when the food particle was dragged either towards or away from the DEJ). Stresses at the trailing edge were usually lower than stresses at the leading edge. Taken together with what is known about prism orientation in primate teeth, such findings imply greater wear resistance at the intercuspal region and less wear resistance at the lateral enamel at midcrown. Such findings appear to be supported by archeological evidence.
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Huang, Han-Ren y 黃漢仁. "Micromechanical analysis of human hard-tissued teeth composite materials". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/14188331978923373716.
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碩士國立中正大學
機械系
99
In the last decades, biomechanics research integrating biology and material mechanics grew to maturity rapidly. Only recently, with the development of nanoindentation instruments, it has been possible to investigate the size, shape and orientation of nanocrystalline micro-structural constituent material of bio-hard tissue (such as tooth). Therefore, the mechanical analysis and modeling of nanostructured bio-composite become a very important research topic. This research studies the microstructural mechanical model of the enamel, which would be established and evaluated with finite element method analysis. Using the basic mechanical theory of composite materials to investigate mechanical problem of bio-tissue could enhance the basic research of biomimetic composite materials. According to the results, exhibiting: (1) the different shapes of each contact surfaces between the enamel rods would affect the values of the normal stress which were reduced by the keyhole rod, and a curved surface could reduce the normal stress. (2) The sheath of enamel could absorb energy induced by shear stress, then to reduce the rod of enamel value of shear stress. (3) The tube of dentin had no significant effects to the tube’s trend of stress distribution. (4) The absorbing strain energy and viscoelastic property were decreased with increasing of angle.
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Huang, Jyun-Yan y 黃俊彥. "Design and Motion Analysis of Two Teeth DifferenceCycloid Reducer". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/bjxhvm.
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碩士國立虎尾科技大學
機械與機電工程研究所
100
This paper studies two teeth difference Discussion on the design and analysis of the reduction gear, two teeth difference cycloid wheel manufactured in Japan Cyclo reducer dismantling draw reference to the internal structure of the traditional bolt instead of the pin wheel inside and outsidethe dental occlusion way analysis of the change in the dynamic simulation and stress analysis. Reverse engineering equipment such as the design process with a special shape parts scanning to find the outline through imaging equipment to pinpoint the parameters of the contour, and then use graphics software to construct the CAD file, and finally use the analysis software for dynamicsimulation and structural analysis, given cycloidal gear and output pins of different sizes designed to explore the different parts of the design parameters, the operation of the overall structure, through which improvements can effectively reduce the vibration and stress values used to achieve precise positioning and growthlife goals.
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Pausch, Niels Christian, Franziska Naether y Karl Friedrich Krey. "Tutanchamun's dentition: the pharaoh and his teeth". 2015. https://ul.qucosa.de/id/qucosa%3A32059.
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Tutankhamun was a Pharaoh of the 18th Dynasty (New Kingdom) in ancient Egypt. Medical and radiological investigations of his skull revealed details about the jaw and teeth status of the mummy. Regarding the jaw relation, a maxillary prognathism, a mandibular retrognathism and micrognathism have been discussed previously. A cephalometric analysis was performed using a lateral skull X-ray and a review of the literature regarding King Tutankhamun´s mummy. The results imply diagnosis of mandibular retrognathism. Furthermore, third molar retention and an incomplete, single cleft palate are present.
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Childs, T. H. C., K. W. Dalgarno, M. H. Hojjati, M. J. Tutt y Andrew J. Day. "The meshing of timing belt teeth in pulley grooves". 1997. http://hdl.handle.net/10454/2378.
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The work described here has been carried out to obtain a better understanding of the tooth root
cracking failure mode of timing belts. Previous work has demonstrated the close dependence of this on the
tooth deflections of fully meshed teeth, generated by torque transmission, but has not considered the
additional distortions generated in the partially meshed conditions at entry to and exit from a pulley groove.
Approximate compatibility and constitutive equations are combined with a rigorous consideration of tooth
equilibrium in partial meshing to show how bending moments are generated at both exit from a driven
pulley and entry to a driving pulley. Experimentally determined belt lives correlate very well with a
combined measure of fully meshed tooth strain and strain due to bending at entry or exit. The analysis also
shows that this strain measure reduces with increasing belt tooth stiffness, confirming the importance of a
high tooth stiffness for a long belt life. Tooth force variations through the partial meshing cycle have also
been predicted and compared with measurements obtained from a special strain gauge instrumented pulley.
A greater pulley rotation than is predicted is required for a belt tooth to seat in a pulley groove. There is
room for improvement in the modelling
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HO, MING-HSUN y 何明勳. "Three-dimensional finite element analysis of stress distribution in pulpless teeth". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/67247286171855197337.
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Wu, Fu-Chuan y 吳福傳. "TOOTH CONTACT ANALYSIS OF STRAIGHT BEVEL GEAR PAIR WITH CROWNING TEETH". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4aed2j.
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碩士國立臺灣科技大學
機械工程系
105
The mathematical models for tooth contact analysis (TCA) of a gear pair have been well derived in the literature. TCA includes evaluation of contact path, angle transmission error, and elliptical contact pattern. The existing method is systematic, efficient, and commonly applied in gear industry. However, it has a drawback in unstable solution when the edge contact happens. Normal vectors of tooth surfaces of the pinion and gear at the edge point do not collinear that leads to a divergence in solving nonlinear equations. In addition, an ellipse is adopted to approach the contact pattern according to curvatures of two tooth surfaces. The deviations of contact pattern get larger while their curvatures change greatly. The paper therefore develops a new mathematical model of TCA. Here, the optimization method of Golden ratio is adopted to directly determine the contact points. The proposed method avoids divergences in solving equations due to avoidance of involving the condition of same normal vectors between the mapped tooth surfaces. Moreover, a searching method for the boundary of contact pattern is applied to find the real contact pattern. The paper also establishes the mathematical models of straight bevel gears, cylindrical gears and spiral bevel gears with double crowning tooth surfaces. Their tooth surfaces are based on a spherical involute, standard involute and face-milled surfaces, respectively. Two methods, the existing and proposed methods, are adopted for evaluating the tooth contact analyses of gear pairs. The results confirm the correctness of the proposed mathematical models.