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1
Young, William G. "Tooth wear /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17715.pdf.
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Kryvoshey, V. "Tooth sensor." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45336.
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Fear of the dentist can be a very serious issue for many children and adolescents. According to academic researches into Dental Fear and Anxiety, some young people hate dentist visits so much that they often refuse to co-operate, or worse - they don’t even go to the dentist. Scientists at Princeton and Tufts have been working a thin tooth sensor that may limit the amount of times we will need to get our teeth checked. The sensor will alert you when it detects any bacteria that could cause cavities, plaque buildup, or any other infections. The scientists say that the new sensor can recognize human oral activities, such as chewing, drinking, speaking and coughing. It also can help to better understand people’s habits and identify potential health problems, such as if a person is smoking or drinking too much. The sensor is so small that it can either fit inside an artificial tooth or straddle a real one.
3
Alfaqeeh, Sarah Ahmad A. "Characterisation and regulation of the tooth-bone interface during tooth development." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/characterisation-and-regulation-of-the-toothbone-interface-during-tooth-development(c9272f5d-7401-4f4c-8933-7c087c775802).html.
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The tooth is closely related to the periodontium in which it sits, with a soft tissue interface forming between the alveolar bone and hard tissues of the tooth. This is known as the tooth-bone interface (TBI). In functional teeth, the TBI houses the periodontal ligament, while during development the TBI creates a space into which the tooth can grow. This project aims to provide an understanding of how the formation of the tooth and bone are coordinated during development and characterise the underlying factors and mechanisms that prevent bone formation and invasion at the interface between the tooth and bone. Using murine mandibular first molar (M1) TRAP stained histological sections, osteoclasts were found to be closely associated with the border of the developing bone, lining the TBI, but not within the TBI itself. Slice culture was used to follow tooth development in explant culture as it provided an excellent opportunity for manipulation and lineage tracing. DiI labelling experiments showed the contribution of two sources of cells in the formation of alveolar bone namely, dental follicle cells from around the tooth and, bone cells from the margins of the dentary. Isolation experiments were used to investigate the impact of the tooth on the bone and bone on the tooth. Isolation of E14.5 mandibular first molar (M1) tooth germ from the surrounding mesenchyme and alveolar bone resulted in tooth germ expansion while removing the tooth epithelium did not change the normal layout of osteoclasts at E14.5. The effect of manipulating the BMP signalling pathway on the differentiation of cells in the TBI during tooth development was studied. A local reduction in the TBI was observed next to the BMP-4 beads whereas a local widening in the TBI was observed when Noggin beads were implanted. The effect of manipulating the RANK-RANKL signalling pathway was investigated next. In situ hybridisation revealed the presence of OPG, RANK, and RANKL in the alveolar bone but OPG and RANKL only in the dental epithelium. Addition of exogenous RANKL to tooth explants in culture resulted in a statistically significant increase in osteoclast numbers and a widening of the TBI. On the other hand, the results obtained after exogenous OPG addition were regarded as inconsistent due to high variability. However, correlation of the difference in bone growth within a cultured tooth germ with the presence of osteoclasts showed absence of osteoclasts in areas of bone encroachment and the opposite, presence of osteoclasts, in areas devoid of bone. The TBI then was analysed in c-Fos mutants, a knockout mouse known to have a defect in osteoclastogenesis, resulting in lack of osteoclast production. Genotyping showed that the c-Fos mutant embryos were displaying the expected Mendelian ratio, but almost all the homozygotes died after birth, and the heterozygotes viability was found to be compromised. Micro-CT analysis of a 3 week old c-Fos homozygote showed a strong osteopetrotic phenotype. Defects in the midline diastema, tooth impaction, and lack of roots were also observed. The TBI showed signs of bone invasion, encroaching on the M1. TRAP assay revealed few positive-stained mononucleated cells, which were probably macrophages. In conclusion this thesis demonstrates that the formation and maintenance of the TBI appears to be a finely regulated two-pronged process with control of osteoclast differentiation used to remove the bone (osteoclastogenesis), combined with inhibition of bone induction (osteogenesis). Together these two processes create a bone-free zone around the tooth. By changing either of these processes the TBI is disrupted and tooth development is altered.
4
Luxford, Yvonne School of History & Philosophy of Science UNSW. "Was the Tooth Fairy breast fed? The politics of infant tooth decay." Awarded by:University of New South Wales. School of History and Philosophy of Science, 2006. http://handle.unsw.edu.au/1959.4/25224.
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In the mid 1970s American paediatric dentists started publishing claims that breast feeding an infant on demand and/or during the night was as dangerous to the infant's dental health, in terms of the production of caries, as the previously established dangers of Baby Bottle Tooth Decay. It was argued by some dentists that this danger increased if the infant was breast fed for an extended period of time. Such claims have gained support from many dentists, and their professional bodies, into the twenty-first century. This thesis examines the historical, social, commercial and cultural influences that supported the development of such assertions. It analyses the ways in which expert reinforcement was gained, and scrutinises the scientific controversy as publicly fought in professional journals and other outlets. The thesis also examines the growing status of the dental profession, especially in connection with its claim to specialised scientific and medical knowledge in the production of dental caries. Further, consideration is given to the medicalisation of breast feeding and the associated commercial infant feeding dispute. The thesis attempts to redress the current lack of theoretical analysis of the construction of dental knowledge. To date there has been minimal academic contribution to the history of dentistry; however, the absence of extensive analysis has been advantageous in enabling an original approach to the material.
5
Baines, David Christian. "Tooth microwear in fishes." Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8753.
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The published articles, p. 149 onwards, are not available in the electronic version of this thesis due to copyright restrictions. The full version can be consulted at the University of Leicester Library.
6
Sarrafpour, Babak. "Studies in tooth movement." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/9746.
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This thesis describes work investigating the mechanisms that result in the eruption of teeth out of the jaws into the mouth, as well as the post-eruptive continuous emergence of teeth once they have entered the mouth. First Chapter summarizes relevant literature on the formation and movement of teeth, and identifies difficulties with the current widely accepted concept of an 'eruptive force' driving teeth into the mouth. Chapter 2 outlines relevant biomechanical principles for Finite Element Analysis (FEA) and by FEA explores the possible role of functional stress in driving continuous post-eruptive emergence of teeth. Data in Chapter 3 support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodeling at the inner surface of the surrounding bony crypt, with the effect of enabling tooth eruption into the mouth. Consequent to work described in Chapter 3, was a need to further characterize mechanosensor activity in dental follicle cells, to that end, Chapter 4 outlines the relevant literature and describes experimental work examining the possible mechanosensor response of cultured dental follicle cells isolated from tissue obtained from extracted wisdom teeth.
7
Hamandi, Rola Riad. "Effects of tooth quality, tooth structure, and cement mixing ratios on dental adhesion." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-06102009-063355/.
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Salakka, Seela. "Tooth Replacement of Euhelopus zdanskyi (Dinosauria: Sauropoda) and the Evolution of Titanosaurian Tooth Morphology." Thesis, Uppsala universitet, Paleobiologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-232847.
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Sauropod tooth morphologies and tooth replacement patterns bear important information on feeding habits and sauropod evolution. Euhelopus zdanskyi is an Early Cretaceous neosauropod, and belongs to the group Euhelopodidae, which is the sister group of Titanosauria. Euhelopus is a key taxon in the evolution of sauropod teeth, because it displays a very conservative tooth morphology compared to that seen in Titanosauria, despite being a close relative. The teeth of Euhelopus resemble those of Camarasaurus, as well as many basal sauropods that are not closely related to Euhelopus. The teeth of Euhelopus are spoon-shaped, and they have approximately two replacement teeth for each functional tooth. Their robust morphology and low number of replacement teeth suggest that they were worn down a lot more slowly than the pencil-shaped teeth of Titanosauria and Diplodocoidea. Diplodocoids, whose teeth have been studied widely, especially show very rapid tooth replacement rates, and the tooth morphology of titanosaurs suggests that they might have had similar replacement rates. On the contrary, Euhelopus was likely to have replacement rates similar to the relatively low rates of Camarasaurus, whose tooth battery is much like that of Euhelopus. Furthermore, some euhelopodids are known to have had pencil-shaped teeth, which indicates that there was a strong evolutionary pressure towards the development of narrow teeth during the Late Cretaceous. This pressure may have been caused by a change in vegetation or may merely represent somphospondylans occupying the niches vacated by the diplodocoids, which appear to have gone extinct before the end of the Cretaceous. This study uses 3D modelling for inspecting tooth replacement of Euhelopus and evolution of sauropod teeth.
9
Courtney, Jo-Maree. "TNF signalling in tooth development." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424467.
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Robb, Nigel Douglas. "Epidemiological studies in tooth wear." Thesis, King's College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308314.
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11
Modino, Sonie Alix Carmen. "Stem cells and tooth development." Thesis, King's College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444559.
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Elamin, Fadil. "Tooth formation in Sudanese children." Thesis, Queen Mary, University of London, 2011. http://qmro.qmul.ac.uk/xmlui/handle/123456789/2339.
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The aim of this study was to describe the average age of permanent mandibular tooth formation in two groups of Sudanese children using a cross-sectional design following STROBE guidelines. The Northern groups are of Arab origin whilst the Western groups are predominantly Fur of African origin (Darfur). North Sudanese sample (844 males, 802 females) consisted of equally distributed, randomly selected healthy university students and school children, whilst the West Sudanese (848 males, 401 females) consisted of a convenience sample attending religious schools in camps for the internally displaced. Panoramic radiographs (2-23 years), with known date of birth were taken. Height and weight were also measured. Developing permanent mandibular teeth were staged from radiographs (Moorrees et al., 1963). The mean age of attainments were calculated using logistic regression and comparisons carried out on 331 tooth stages to determine gender and ethnic differences. Results showed that mean age of attainment of teeth was not significantly different between the genders within each ethnic group (p>0.05) for 135 out of 155 stage comparisons. The mean age of attainment of teeth was not significantly different between same sex groups in 113 out of 174 stage comparisons (p>0.05). The canine was more advanced in females compared to males while the reverse was true for some crown and root stages of third molars. Growth indicators showed that all groups are undernourished (z-scores =< -2). Severe malnutrition had minimal effect on tooth formation of M1 and M2 (p>0.05) in Northern females. The prevalence of hypodontia (excluding third molars) was 0.7% in the Western group and 2.6% in the Northern group. The pattern of hypodontia differed between groups. In conclusion, the within group variation for most tooth stages is considerable while the differences between groups are small. The study represents the first radiographic investigation of permanent tooth formation in Africa.
13
Lam, Garret Chi Yan. "Biomechanics of orthodontic tooth movement /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20LAM.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 118-122). Also available in electronic version. Access restricted to campus users.
14
Wedenberg, Cecilia. "Development and morphology of internal resorption of teeth a study in humans, monkeys and rats /." Stockholm : Kongl Carolinska Medico Chirurgiska Institutet, 1987. http://catalog.hathitrust.org/api/volumes/oclc/16149996.html.
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15
White, Andrew John. "The biophysical chemistry of tooth surfaces : protein and peptide-based technologies for inhibiting erosive tooth wear." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550331.
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Dental erosion is an increasing problem in many countries around the world, and research in this field has increased dramatically in recent years. Dental erosion is the dissolution of tooth tissues by acids that are not of bacterial origin; most commonly these originate from the diet. Methods to reduce erosion are of great import; the application of milk-derived proteins such as casein and casein-derived proteins are of current interest as anti-erosion agents and are the subject of the work presented here in this thesis. The efficacy of casein and casein-derived proteins as agents to inhibit dissolution of hydroxyapatite in simple citric acid solutions are investigated in chapters 3 and 4 with two different in vitro models. It was found that these proteins inhibit hydroxyapatite dissolution over a range of erosion timescales, concentrations and exposure times. The effect of an in vitro formed salivary pellicle is also examined and the proteins were shown to retain their efficacy. The efficacy of these proteins to inhibit the earliest stages of erosion (surface softening) and more progressed stages of erosion (bulk tissue loss) are investigated in chapter 5 using atomic force microscopy nanoindentation and non-contact optical profilometry respectively. It was found that again these proteins inhibit both surface softening and bulk tissue loss of bovine enamel. The nature of the protective mechanism due to casein is investigated in chapter 6 using a range of complementary, inter-disciplinary techniques such as atomic force microscopy, x-ray reflectometry and sodium dodecyl sulphate polyacrylamide gel electrophoresis. The protective effect is ascribed to a thin protein film, of 6.6 nm in thickness, forming on the mineral surface. In conclusion, casein and casein-derived proteins are shown to have anti-erosion properties and potential as oral healthcare products.
16
Lentini, Erika. "Endodontic Radiolucency on a Mature Permanent Tooth in the Pediatric Population: Can the Tooth be Vital?" VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3329.
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The objective was to determine the prevalence of vital teeth requiring non-surgical root canal therapy (NSRCT) that present with radiolucencies in mature permanent teeth in a pediatric population. A retrospective electronic dental chart review of children treated with NSRCT at VCU’s School of Dentistry between November 30, 2009 and March 1, 2013 was conducted. The presence or absence of a periapical radiolucency was determined from digital radiographs by three calibrated dentists. Specific characteristics of each tooth were collected. Statistical analysis using logistic regression was completed on all teeth with radiolucencies and vital teeth with radiolucencies. NSRCT was completed on 551 teeth. Radiolucencies were present in 246 teeth. Vitality data on access was only available in 184 teeth. In these, the prevalence of vital teeth with radiolucencies was 45.1% (n=83). Significant differences were noted for tooth type, gender, and puberty. Post-pubertal subjects had more vital teeth with radiolucencies than pubertal subjects.
17
Vaahtokari, Anne. "Molecular mechanisms in embryonic tooth development." Helsinki : Dept. of Dentistry, Division of Pedodontics and Orthodontics, Institute of Biotechnology and Dept. of Biosciences, Division of Biochemistry, University of Helsinki, 1996. http://catalog.hathitrust.org/api/volumes/oclc/35253532.html.
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18
Weninger, Malin. "Blue tooth : test of devices range." Thesis, University West, Department of Informatics and Mathematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-646.
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Mistry, Miten Bharatkumar. "In vitro investigation of tooth erosion." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/in-vitro-investigation-of-tooth-erosion(ff317ff4-a94a-4476-992c-93438de363f2).html.
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In vitro investigations in dental research are important as they allow for conditions such as tooth erosion to be extensively studied in controlled environments for product development and testing. The studies in this thesis investigate citric, phosphoric and hydrochloric acids under varying conditions of concentrations and immersion times in erosion and erosionabrasion models and use non-contact profilometry and Knoop microhardness to measure the change in the surface of enamel. The effects of different experimental protocols on profilometry and Knoop microhardness were investigated. Using the results from these preliminary studies, a modified erosion model was developed to investigate the effects of low concentration fluorides and time of application. The role of fluoride experiment was furthered by investigating a dose response effect using sodium and stannous fluoride at concentrations normally found in mouth rinses and toothpastes. Citric and phosphoric acid were more erosive than hydrochloric acid at pH 3.2. The effect of increasing the immersion time and concentration increased the amount of erosion. The addition of abrasion produced a non-linear response, suggesting a more complex mechanism was operating rather than the simple eroded surface being more susceptible to abrasion. Profilometry and to a lesser extent Knoop microhardness were effective measurements to quantify the amount of erosion. Tooth surface/type, ultrasonication, storage, agitation and speed, rinsing, volume and position of sample all influenced the mean step height and Knoop microhardness change. Stannous fluoride (225ppm) produced significantly lower (p<0.001) mean step height and higher Knoop microhardness change than sodium fluoride. The application before an erosive challenge produced a significantly lower mean step height (p<0.04) for stannous fluoride compared to the application after. A dose response effect was observed between the different fluorides. Both fluorides produced significantly lower mean step height (p<0.001) and Knoop microhardness (p<0.001) change compared to the control. Sodium fluoride provided less protection (significantly higher mean step height) (p<0.05) compared to stannous fluoride. These studies show that the different experimental protocols can influence the measured outcome and that further work is needed to fully understand the effects of all the experimental protocols and abrasion. Greater standardisation and detailed reporting in method sections need to be promoted in in vitro dental research.
20
Tsui, Wai-kin, and 徐偉堅. "Bone anchorage for orthodontic tooth movement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44661605.
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Al-Omiri, M. K. "Tooth wear impact on daily living." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269042.
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Birch, W. J. "Incremental growth of deciduous tooth enamel." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1348309/.
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Deciduous tooth formation begins before birth and ends after birth. This makes it more difficult to construct a continuous developmental chronology for deciduous teeth than for permanent teeth. The discovery of the neonatal line in enamel and confirmation that it marks birth, allowed the expansion of deciduous dental chronologies, which until this time had been largely based on qualitative descriptions. The aim of this study was to use the daily incremental record in deciduous enamel to document rates of enamel formation and to use these data to produce regression equations that describe the average rates of deciduous enamel formation for each tooth type. These formulae can then be applied to all deciduous teeth even when daily increments are not visible, in order to estimate crown formation times and other events during crown development, as well as to determine the age at death where enamel formation has ceased prior to completion. In permanent teeth, rates of enamel formation vary between 2.5μm per day at the EDJ to 6.5μm per day at the enamel surface. Seventy deciduous ground sections were examined and it was established that the daily rates in deciduous enamel varied less, with regional weighted means for all tooth types ranging from 2.85μm per day at the EDJ to 3.40μm per day at the enamel surface with extreme outliers of 2.07 to 4.97μm per day. The average daily incremental growth rate of enamel in deciduous teeth was calculated for each tooth type, the weighted mean of the apposition rate over both aspects (labial/buccal and lingual) and over all three regions (cervical, lateral and occlusal) for all tooth types was 3.23μm per day. A key finding of this study was that there is a marked reduction in the enamel formation rate in the zone immediately following the neonatal line or following other accentuated striae assumed to be associated with stressful events. A catch-up phase usually followed these events, during which the previous rates recovered. These data provide clear evidence of enamel hypoplasia associated with both the birth process and other events that cause stress in perinatal life.
23
Batyuk, A. "Chocolate toothpaste for a sweet tooth." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/40530.
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What do we mean saying ―a beautiful smile‖? Well, first of
all, it is a sincere smile. What makes it beautiful? – White and
healthy teeth. The most important helper for us is a toothbrush. A
toothbrush is used with a toothpaste, and the choice of it is rather
important, too. As a rule, toothpaste contains various antimicrobial,
deodorizing, bleaching, medical and other components. The main
task of paste is to clean, fresh your mouth, make brushing more
enjoyable, to keep gums healthy, to prevent the development of
cavities and whiten our teeth.
24
Badenoch-Jones, Emma K. "Consent for third molar tooth extractions." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123066/1/Emma_Badenoch-Jones_Thesis.pdf.
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This project is an important contribution to the field of medico-legal practice in surgery. The thesis provides perspectives in deficient areas of objective evidence on consent for third molar tooth extractions through defined patient and judicial disclosures and understanding. The outcome of the project is an evidence-based consent form for third molar tooth extractions that will enhance the standard of patient information disclosure for this procedure by general dentists and oral and maxillofacial surgeons. The methodological process adopted is also one that can be replicated in other medical fields to yield objective evidence to guide the process of consent for any medical procedure.
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DIANA, MICHELA. "Tooth-coil wound multiphase synchronous machines." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2713044.
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Nowadays we are witnessing a strong growth in the full electric vehicle market.
In the field of traction the requirements are low weight, small dimensions and low
cost, without renouncing reliability and good performances. The high power density
requirement is pushing the research towards integrated drive solutions. A particular
drive that allows to obtain more insightful integrated solutions is the multi-phase one.
In fact, in multi-phase structures it is possible to realize a converter as a combination
of standard modules with an equal subdivision of the current. The resulting power
electronics modules meet the needs of an integrated solution: smaller and widely
distributed.
Although road electric vehicles primarily adopt 3-phase drives, the multi-phase
version could represent a good alternative not only for its integration capability
but also for other features like reduced weight and volume, high efficiency, low
vibrations and noise, robustness and, overall, fault tolerance. The aim of this thesis is
to investigate a particular category of multiphase machines, characterized by a very
simple structure that allows to match manufacturing and performance standards.
In Chapter 1, the subcategory of multiphase machine object of the investigation
is identified. Considering a simple stator structure, as the tooth-coil wound, a
general algorithm to identify the right stator-rotor coupling in multiphase machine is
presented.
In Chapter 2, an analytical and generalized formulation of the harmonic fields at
the air gap for the multi-n-phase solutions chosen is reported allowing to understand
and quantify the harmonic compensation in the MMF. Starting from the Lorenz
Force Law an analytical formulation of the torque and torque ripple is then proposed.
The model proposed has been then verified by Finite Element Analysis (FEA).
In Chapter 3, the main issues tackled in the design of a nine phase machine are
reported. Between the possible solutions a 9 slot 10 poles PM-inset machine has
been chosen. The chapter reports the evaluation of the performance conducted by the
time stepping FEA. The chapter reports the experimental results that were conducted
on a prototype. A description of the control infrastructure is reported.
In Chapter 4, a simple modulation strategy that allows to reduce the DC-link
stress for a triple-3-phase drive is presented. The analysis of the benefits introduced
by the PWM phase shifting are evaluated by steady state simulations ,using the
software Pspice, in all the possible operating conditions. A worst case approach has
been chosen in order to find the best angle of shifting between carriers to reduce
the DC-link rms current in multi-3-phase drives. The results of the experimental
validation are reported. The same analysis has been extended to sectored multiphase.
In Chapter 5, a mathematical model is proposed in order to evaluate the torque
and the torque ripple in fractional slot tooth-coil wound (TCW) Synchronous Reluctance
(SyR) machines. Considering a generic harmonic field and an ideal SyR rotor,
the rotor magnetic potential is modelled and the torque equations are calculated
starting from the Lorenz Force Law. Time stepping FEA results are reported in order
to verify the formulations.
Appendix A reports the mathematical demonstration that defines the rotor reaction
for an ideal SyR rotor together with the methodologies used to design the SyR
constant permeance rotor.
Appendix B reports the manufacturing process of the machine.
Appendix C reports the COOL-TIE concept: a cooling devices for the electrical
machine compatible with the power electronic integration
26
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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Fure, Solveig. "Studies of root surface caries prevalence and associated factors /." Göteborg : University of Göteborg, 1990. http://books.google.com/books?id=MhBqAAAAMAAJ.
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Abdallah, Mohamed Nur. "Surface reactivity of tooth enamel with dyes, oxidizing agents and magnesium ions and its effect on tooth color." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117232.
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Enamel, the outer protective layer of human teeth, is constantly interacting with its surrounding harsh environment. These interactions play a major role in many mechanisms that affect the dental health such as tooth caries, tooth discoloration and plaque formation. Accordingly, most treatments used to maintain and/or restore dental health focus first on the enamel surface. Even though most of the enamel structure has been thoroughly studied, many of the enamel surface features, and the chemical reaction that occur on it, are not well understood. Extrinsic tooth discoloration poses a major problem to many patients and dentists. Most causes of extrinsic tooth staining have been well identified and are usually treated with hydrogen peroxide. However, the mechanism of extrinsic tooth discoloration and tooth bleaching using peroxide oxidizers are not fully understood. It is unknown why certain staining molecules attach to the enamel surface, whether peroxide radicals make teeth whiter by removing these stains, and why sometimes hydrogen peroxide does not work. Also, treating darkened teeth with peroxide agents has its limitations and disadvantages. This has pushed us to look for better and less harmful whitening agents. Recent studies have revealed that there is a correlation between crystallographic characteristics of enamel and its physical properties, such as tooth shade and microhardness. This discovery predicts that tooth properties can be changed by modifying its crystallographic structure. Since magnesium ions are known to react with synthetic hydroxyapatite and affect its crystallographic properties, it is possible that magnesium ions could react with dental enamel and induce changes in dental enamel crystallographic, optical and mechanical properties. Several significant conclusions and achievements are presented in this thesis. We demonstrated the presence of a carbon rich layer on the surface of enamel that contains relatively high amounts of calcium. This layer might explain the high staining ability of certain types of anionic staining agents that are among the most common causes of external tooth discoloration. Moreover, we showed that hydrogen peroxide does not induce significant changes in tooth enamel organic and inorganic relative contents, and it whitens teeth just by oxidizing their organic matrix. This finding is of great clinical significance since it explains the mechanism of tooth bleaching and the reasons behind the limited predictability of the treatment outcomes. Finally, we showed for the first time that magnesium ions can react with tooth enamel and induce a reduction in the size of enamel hydroxyapatite nanocrystals. This change in crystallography affected the enamel optical and mechanical properties; making the enamel harder and whiter. This is a new method that can be exploited to whiten teeth without using peroxide-based bleaching agents. We concluded that crystallographic ultrastructure plays a key role in defining the tooth enamel properties which can be tailored through ionic substitution for improvement of optical and mechanical properties without causing the possible negative effects of peroxide agents.L'émail est la couche protectrice externe des dents humaines en constante interaction avec son environnement hostile. Ces interactions jouent un rôle important dans de nombreux mécanismes qui influencent la santé dentaire, tels que les caries dentaire, la coloration dentaire et la formation de plaque. Par conséquence, la majorité des traitements utilisés pour maintenir et/ou restaurer la santé dentaire se concentre principalement sur la surface de l'émail. Tandis que la structure de l'émail a été largement étudiée, les caractéristiques de sa surface, ainsi que les réactions chimiques se produisant à son niveau ont rarement été décrites. La coloration extrinsèque des dents pose un problème majeur pour certains patients et dentistes. La majorité des causes de colorations extrinsèques des dents ont été bien identifiées et sont habituellement traitées avec du peroxyde d'hydrogène. Cependant, le mécanisme de coloration extrinsèque des dents et de blanchiment des dents à l'aide des oxydants du peroxyde ne sont pas entièrement décrits. Les raisons pour lesquelles certaines molécules colorantes s'attachent à la surface de l'émail, comment les radicaux de peroxyde peuvent blanchir les dents en enlevant ces colorations, ainsi que la raison pour laquelle le peroxyde d'hydrogène n'est pas optimal en terme de blanchiment des dents, restent toujours méconnus. De plus, le traitement avec des agents de peroxyde de dents noircies présente certaines limitations et inconvénients. Ce qui nous a motivés à intensifier les recherches pour de meilleurs agents de blanchiment avec le moins d'effets nuisibles.Des études récentes ont montré qu'il existait une corrélation entre les caractéristiques cristallographiques de l'émail et ses propriétés physiques, comme la couleur de la dent et la microdureté. Cette découverte prédit que les propriétés de la dent peuvent être changées par la modification de sa structure cristallographique. Comme les ions du magnésium sont connus de leur capacité de réagir avec l'hydroxyapatite synthétique et d'affecter ses propriétés cristallographiques, il est possible que ces ions puissent réagir avec l'émail dentaire et induire des changements cristallographiques à son niveau ainsi que des changements de ses propriétés optiques et mécaniques.Plusieurs conclusions et réalisations importantes sont présentées dans cette thèse. Nous avons montré la présence d'une couche riche en carbone sur la surface de l'émail qui contient des quantités relativement élevées de calcium. Cette couche pourrait expliquer la capacité colorante élevée de certains types d'agents anioniques, qui sont parmi les causes les plus communes de la coloration extrinsèque des dents. De plus, nous avons montré que le peroxyde d'hydrogène ne provoque pas de changements significatifs dans le contenu organique et inorganique relatif à l'émail des dents, ainsi qu'il blanchit les dents uniquement en oxydant leur matrice organique. Cette conclusion est d'une valeur clinique importante car elle explique le mécanisme de blanchiment des dents et les raisons de la prévisibilité limitée des résultats du traitement. Enfin, nous avons montré pour la première fois que les ions du magnésium puissent réagir avec l'émail des dents et provoquent une réduction de la taille des nano-cristaux d'hydroxyapatite. Ce changement dans la cristallographie affecte les propriétés optiques et mécaniques de l'émail et le rend plus dur et plus blanc. Cette nouvelle méthode peut être exploitée pour blanchir les dents sans avoir recours à l'utilisation d'agents de blanchiment à base du peroxyde. Nous avons conclu que l'ultrastructure cristallographique joue un rôle clé dans la définition des propriétés de l'émail des dents, ce qui peut être ajusté par la substitution ionique afin d'améliorer les propriétés optiques et mécaniques et sans causer des effets potentiels nocifs des agents basés sur le peroxyde.
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Hemingway, Catherine Anne. "The interaction of food-approved proteins and salivary pellicle on tooth surfaces and their impact on tooth demineralisation." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496224.
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Demineralisation of the dental hard tissues by acidic beverages is thought to be one of the most important etiological factors in dental erosion. The influence of the chemical parameters of soft drinks on erosion has been studied by many investigators. There have been attempts to produce low erosive soft drinks by altering pH and calcium concentration, and moderately successful products have been developed, but the detrimental effect on beverage taste is a major drawback. In conclusion, it has been shown that the erosion rate of HA and dental tissues in acid can be inhibited by changing many parameters and that in terms of drink moaiTicaiion tne aaaition or certain food approved polymers can inhibit dissolution.
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Vogel, Olaf [Verfasser]. "Gear-Tooth-Flank and Gear-Tooth-Contact Analysis for Hypoid Gears : An Application of Singularity Theory / Olaf Vogel." Aachen : Shaker, 2007. http://d-nb.info/1170528155/34.
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Beaumont, Julia. "The whole tooth and nothing but the tooth: or why temporal resolution of bone collagen may be unreliable." Wiley, 2020. http://hdl.handle.net/10454/17648.
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YesThe carbon (δ13C) and nitrogen (δ15N) isotope ratios of human bone collagen have been used extensively over the last 40 years to investigate the diet of past populations. It has become apparent that bone collagen can give an unreliable temporal dietary signature especially in juveniles. With higher temporal resolution sampling of collagen from tooth dentine, it is possible to identify short‐term changes in diet previously invisible in bone. This paper discusses the inherent problems of using bone collagen for dietary studies and suggests better sample choices which can make our interpretations more robust, using breastfeeding and weaning as an example.
The modern data was collected and analysed using funding from the Rank Prize Funds New Investigator Award and sponsorship from DB Orthodontics, Bradford. The Tooth Fairy team acknowledges the support of the National Institute for Health Research Clinical Research Network (NIHR CRN).
The full-text of this article will be released for public view at the end of the publisher embargo on 06 Feb 2022.
Research Development Fund Publication Prize Award winner, February 2020.
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Brodarac, Andreja. "Impaired tooth development in Periostin deficient mice." [S.l.] : [s.n.], 2006. http://www.sub.uni-hamburg.de/opus/volltexte/2006/3106/index.html.
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DeCaires, Brian J. "Variation analysis of involute spline tooth contact /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1176.pdf.
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Bergseth, Ellen. "On tribological design in gear tooth contacts." Doctoral thesis, KTH, Maskinelement, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102742.
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The correct tribological design will have a considerable effect on a gear’s service life and efficiency. The purpose of this thesis is to clarify the impact of variation in the gear tooth flank tribological system on the gear contact load capacity – to increase the understanding of how surface topography and lubricant interact. In this thesis the variation in surface topography inherent in the manufacturing method has been shown, by experimental work and computer simulations, to be an important factor for the contact condition in the early life of gears. Surface analysis revealed that the formation and composition of surface boundary layers depends strongly on the chemical composition of the lubricant, but also on pre-existing surface boundary layers. Additionally, surface boundary layers play a major role in frictional behaviour, wear and in allowing the lubricant to react properly with the surfaces. Paper A presents the current ISO 6336 calculation of surface durability. A robust design approach was used to investigate the extent to which the current standard for calculation of surface durability allows for manufacturing variations and the choice of lubricant. Paper B investigates the extent to which a logarithmical profile modification can increase gear contact pressure robustness compared to traditional lead profiles for gears. Paper C compares different gear manufacturing methods and their as-manufactured (fresh unworn) surface topographies, using measured surface topographies as input to a contact simulation program. Paper D examines surface boundary layer formation and the corresponding wear in relation to different anti-wear additives in an environmentally adapted base oil. Papers E and F make use of specimens with surface topographies imitating two gear manufacturing methods (grinding and superfinishing) to be used in a twin-disc and barrel-on-disc machine respectively. The contacts are analysed by friction measurements and simulations combined with methods for surface analysis.QC 20120925
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Salman, Saad Ahmed. "An Analysis of Single Tooth Milling Operation." Thesis, KTH, Industriell produktion, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102553.
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This study examines the possible mechanisms found on hobs used in gear cutting by using a single insert face milling test. Cutting inserts are used to represent hob teeth.The two types of inserts used in this thesis, namely surface-prepared and edge-prepared insert, have been considered as inputs for the experiments. The basic objective of this work is to find out the behavioural patterns shown by the above-mentioned inserts during milling operations. After going through this thesis paper, one can comprehend various information during milling operation with the help of the illustrated graphs and diagrams, which have been inferred after extensive analysis. The output from this thesis would be the information assemblage of cutting force, vibration, chip thickness, engagement energy, tool losing edge volume and machined surface on work piece.
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Agenter, Michael Kelly. "Influence of tooth crown size on malocclusion." View the abstract Download the full-text PDF version (on campus access only), 2008. http://etd.utmem.edu/ABSTRACTS/2008-001-Agenter-index.html.
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Thesis (M.S. )--University of Tennessee Health Science Center, 2008.Title from title page screen (viewed on March 4, 2008 ). Research advisor: Edward Harris, Ph.D. Document formatted into pages (xvii, 192 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 155-166).
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Cherukara, George Philip. "Tooth preparation for porcelain veneers : an analysis." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423185.
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Brookes, Julie Bridget. "An evaluation of tooth clipping in piglets." Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262281.
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Luo, Wen. "Assessment of Tooth Colour using Digital Imaging." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485749.
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As tooth whitening has become a popular and routine dental procedure, the measurement of tooth colour, especially for the evaluation of the efficacy of the tooth-whitening products, has become important. One of the instrumental methods of assessing tooth whiteness is digital photography. The aim of this study was to develop a digital imaging method in colorimetry of human teeth which could be used for evaluating the efficacy of tooth-whitening products. The successful use .of a tooth-imaging system for assessing tooth whiteness relies upon two things: precise and preferably accurate colour-rendering for teeth, and an appropriate whiteness scale or index for quantifying the tooth whiteness according to human perception. These two things are the main objectives needed to be achieved in this study. The development of the tooth-imaging system consists of two essential procedures: calibration and characterisation. The imaging system was firstly calibrated according to the requirements of clinical tooth-colour measurement, including accurate control of the intensity of the light source with the aid of software. For camera characterisation, besides the traditional methods, efforts were made by choosing training samples that are physically similar to real human teeth for the characterisation model to improve the accuracy of the system. Two cameras were evaluated and several characterisation models were compared. Moreover, uncertainties involved in the clinical tooth-colour measurement were investigated as a complementarity to the performance of the tooth-imaging system. In order to find the relationship between the objective measurements and visual assessments of tooth whiteness, psychophysical experiments were conducted in a controlled viewing condition as well as a typical clinical viewing condition. A whiteness index for quantifying tooth whiteness was proposed and its performance was compared with some existing whiteness/yellowness indices. Finally, the validation of the tooth-imaging system and the tooth-whiteness index were assessed under the conditions of clinical whitening trials. In addition to the tooth-whiteness study, the gloss of tooth, as one part of the tooth appearance, was investigated on a gonio-imaging system which was verified by results from the repeatability test and the tooth-etching experiments.
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Metwally, H. M. B. "Multi-tooth per pole variable reluctance motors." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370148.
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Kupczik, Kornelius Florian. "Tooth root morphology in primates and carnivores." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408708.
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Popa, Mihaela. "Tooth cleaning : abrasive particles but no abrasion." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI034.
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En 1997 Stuard L. Fischman a dit « Certainement on mange bien, on parle bien, on a l'air bien et on « sent frais » - mais on a aussi la plaque dentaire, la gingivite et les caries dentaires. Le lecteur peut déterminer les progrès réalisés en réfléchissant à son état de santé bucco-dentaire personnel! ». Vingt ans plus tard cette affirmation reste valide. L'acte le plus commun d'hygiène buccale est de se nettoyer les dents par brosse à dents, eau et dentifrice. Le rôle principal de la brosse à dents et du dentifrice est d'éliminer le biofilm dentaire responsable des maladies buccales. Il est largement admis que le biofilm dentaire est éliminé au moyen de particules de nettoyage trouvés dans la composition du dentifrice. Puisque le mécanisme des particules nettoyantes est couramment supposé abrasif, la recherche sur le nettoyage des dents a été principalement conduite du point de vue « abrasif », elles sont ainsi appelées « particules abrasives ». Néanmoins, le nettoyage des dents est un processus complexe impliquant plusieurs mécanismes (biochimiques, physico-chimiques et mécaniques), chacun activé par des facteurs à la fois internes (comme l'environnement oral individuel et les habitudes individuelles d'hygiène buccale) et externes La conception de la brosse à dents et la composition de dentifrice). Ce travail a commencé à partir de l'idée que le nettoyage des dents ne peut pas être réduit à un processus d'abrasion; par conséquence, afin d'acquérir une connaissance plus profonde du comportement réel des particules nettoyantes, il est nécessaire de comprendre la contribution de chaque mécanisme d'action impliqué. Un système biomimétique a été développé pour reproduire la brosse à dents, l'émail dentaire, la pellicule exogène acquise et le dentifrice (une suspension simplifiée à base de silice). Le système a été analysé d'un point de vue tribologique, en adoptant la théorie du « troisième corps » et en utilisant différentes techniques expérimentales (spectroscopie infrarouge, microscopie à force atomique, la microscopie électronique à balayage). On a déterminé la contribution de la mécanique et de la physico-chimie de la surface de l'émail dentaire, de la chimie du dentifrice et de la mécanique de la brosse à dents. Les résultats ont montré que la pellicule exogène acquise biomimétique n'a pas été rayée pendant le nettoyage des dents, mais plutôt lissée ou enlevée, ce qui suggère que l'abrasion n'est pas le mécanisme «gouvernant» du processus de brossage des dents. En effet, un mécanisme de «lubrification fractionnée» est supposé intervenir, favorisant la formation des agglomérats de silice supportent la charge normale dans des zones de contact localisées. L'efficacité du processus de nettoyage des dents est censée être contrôlée par la taille des agglomérats de silice, qui dépend à son tour de la mécanique et la physico-chimie de la surface de l’émail dentaire, de la chimie du dentifrice et de la mécanique de la brosse à dentsIn 1997, Stuart L. Fischman wrote “We certainly eat well, speak well, look fine and ‘smell fresh’—but we also have plaque, gingivitis and dental caries. The reader can determine how much progress has been made by reflecting on his or her personal oral health status!” Two decades later, this affirmation is still valid. The most common act of oral hygiene is to clean one’s teeth via toothbrush, water, and dentifrice. The main role of toothbrush and dentifrice is to remove the dental biofilm responsible for oral diseases. Over the years, several studies have focused on improving toothbrushing techniques, toothbrush design, and dentifrice composition, often leading to conflicting results. It is largely accepted that dental biofilm is removed by means of cleansing particles, which can be found in many dentifrice compositions. Since the mechanism of the cleansing particles is commonly believed to be abrasive, research on teeth cleaning has been mainly conducted from an ‘abrasive’ point of view, so much so that cleansing particles are frequently referred to as ‘abrasive particles’. Nonetheless, teeth cleaning is a complex process involving several mechanisms (bio-chemical, physico-chemical, and mechanical), each one activated by factors that are both internal (such as individual oral environment and individual oral hygiene habits) and external (such as toothbrush design and dentifrice composition). This work started from the idea that teeth cleaning cannot be reduced to an abrasion process; consequently, in order to gain deeper knowledge about the actual behavior of the cleansing particles, it is necessary to understand the contribution of each mechanism involved. A biomimetic system was developed to reproduce toothbrush, dental enamel, acquired enamel pellicle, and dentifrice (modeled as a silica-based slurry). The system was analyzed from a tribological point of view, adopting the ‘third-body approach’ and employing different experimental techniques such as infrared spectroscopy, atomic force microscopy, and environmental scanning electron microscopy. The contribution of the dental enamel surface mechanics and physico-chemistry, of the dentifrice chemistry, and of toothbrush mechanics was assessed. Results showed that the biomimetic acquired enamel pellicle was not scratched during teeth cleaning, but rather smoothened or removed, suggesting that abrasion is not the governing mechanism of the toothbrushing process. Indeed, a ‘fractionated lubrication’ mechanism is believed to take part, promoting the formation of silica agglomerates that bear normal load at localized contact areas. The effectiveness of the teeth cleaning process is believed to be controlled by the size of the silica agglomerates, which in turn depends on dental enamel surface mechanics and physico-chemistry, dentifrice chemistry, and toothbrush mechanics
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Broomhead, Tom. "Neighbourhood effects : spatial inequalities in tooth decay." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/20729/.
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Objectives: Little theoretical work has been conducted on the topic of neighbourhood effects on health outcomes, let alone within dentistry. Previous work has often quantified and described outcomes without proper investigation of potential causal mechanisms and pathways. Therefore, the aim of this exploratory research was to investigate features of neighbourhood environments that may influence tooth decay in adults. Methods: Relevant literature was mapped onto a neighbourhood based theoretical framework to create numerous pathways by which neighbourhoods influence decay. Spatial microsimulation was used to combine data from the Adult Dental Health Survey (2009) with Census data to create a synthetic dataset of individuals at the small area level for the city of Sheffield (UK), including associated socio-economic, demographic and dental characteristics. This data formed the basis of the agent-based models which were used to test the theoretical pathways in two contrasting study areas in Sheffield, as well as a hypothetical scenario involving an extra shop being added to each location. Results: The trends of the agent-based models indicated that the same pathway (the interaction between shops, diet and sugar intake) had the largest impact in both study areas, leading to statistically significant increases in decay in both cases (p < 0.05). The results of the hypothetical simulation involving an extra shop revealed a statistically significant decrease in decay in the more affluent study area (p < 0.05), while decay scores remained similar in the less affluent study area. Conclusions: The findings suggest the interactions between shops, diet and sugar intake may be the most important neighbourhood based mechanisms for tooth decay, regardless of socio-economic status. However, additional simulations pointed to more opportunities to reduce decay in the more affluent study area through the local food environment. The implications of these findings are discussed in light of previous research and future work.
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McLennan, Laura. "Tooth wear, microwear and diet in elasmobranchs." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42779.
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As abundant and widespread apex predators, elasmobranchs play influential roles in the food-web dynamics of marine communities. This has obvious implications for fisheries management and marine conservation. For successful conservation, the ecology of a species must be known. An understanding of extinct species ecology is also useful. Unfortunately, diet a key component of a species’ ecology, is relatively understudied in elasmobranchs. For a majority of elasmobranch species, little or no quantitative dietary data exists. This reflects the limitations of current dietary defining methods. This thesis presents two alternative methods that can be used to determine the diet of extinct and extant elasmobranchs: meso-style wear analysis and 3D tooth microtextural analysis. These wear techniques can be applied to small sample sizes, and sampled animals with no stomach contents, thus reducing the impact of study on wild elasmobranch populations. The techniques can also be applied to dried and fossil samples, further reducing the impact of study on wild populations and providing a means for the study of extinct species. Furthermore, these wear techniques provide additional advantages over the traditional methods of stomach contents analysis and observation. The wear, measured through the methods outlined in this thesis, accumulates over a longer timescale. The “snapshot bias” associated with traditional methods is thus overcome when analysing diet via meso-style analyses or 3D microtextural analyses. This thesis also investigates the impact of sediment abrasion to 3D tooth microtextures. Results show that care needs to be taken when comparing fossil specimens originating from deposits with differing sediment compositions. These findings are applicable to any study using 3D microtextural techniques on fossil specimens of any species, as all have been exposed to sediment abrasion before fossilisation. This is the first time that these alternative wear methods have been applied to elasmobranchs. They have displayed the potential to be a powerful tool for the dietary analysis of living and extinct elasmobranchs in the future.
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Olley, Ryan. "Association of dentine hypersensitivity to tooth wear." Thesis, King's College London (University of London), 2012. https://kclpure.kcl.ac.uk/portal/en/theses/association-of-dentine-hypersensitivity-to-tooth-wear(09a7f9b3-e0a7-4f4c-8a2e-b926a89cffc2).html.
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Dentine hypersensitivity (DH) affects up to 57% of patients following exposure of unoccluded dentine tubules. However the aetiology is incompletely understood. These studies investigated the association of DH to tooth wear. A prevalence study investigated risk factors associated with tooth wear and DH on all tooth surfaces in 350 subjects aged 18-35 in SE England. Sextant cumulative scores for DH and tooth wear were validated and positive correlations existed between both (p < 0.0001). Two randomised, single blind in situ studies investigated the degree of dentine tubule occlusion provided by desensitising dentifrices following four days of twice daily brushing with agitated acid challenges on days three and four. In the first in situ study involving 28 healthy subjects, samples were imaged daily using Scanning Electron Microscopy (SEM) and graded using a ‘standard’ visual ordinal scale. On days one and two, an 8% strontium acetate and 8% arginine based desensitising dentifrice demonstrated more occlusion than control paste (p < 0.0001) and water (p < 0.0001, p = 0.0003). On day four, strontium demonstrated more occlusion than all other treatments (p < 0.0001). In a second in situ study involving 30 subjects, an innovative computerised and imaging method was created and validated to quantify tubule occlusion. Samples were imaged with Tandem Scanning Microscopy (TSM) and then SEM. Intra-class correlation of the number of un-occluded tubules counted visually and then by the computational analysis on 10% (n = 47) randomised SEM or TSM images was > 0.8. Positive Spearman correlations existed between the visual ordinal ‘standard’ and the SEM (r = 0.58) and TSM (r = 0.42) computational analyses (p < 0.001, n = 469). At day four, the TSM computational analysis and the ‘standard’ showed that an experimental dentifrice containing 5% calcium sodium phosphosilicate produced more occlusion than controls (p < 0.0001). These studies refute the null hypothesis that there is no association between DH, tooth wear and the patency of the dentine tubules. Accurate techniques were developed to measure DH.
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Cruwys, Elizabeth. "Tooth wear patterns in modern human populations." Thesis, University of Cambridge, 1987. https://www.repository.cam.ac.uk/handle/1810/272343.
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Chojnowski, Alexandre. "Myotubularines et maladie de Charcot-Marie-Tooth." Paris 5, 2007. http://www.theses.fr/2007PA05D001.
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La maladie de Charcot Marie Tooth (CMT) est la neuropathie périphérique héréditaire la plus commune chez l'homme ; elle affecte environ une personne sur 2500. A ce jour, plus de 20 gènes ont été liés à une des formes de CMT et parmi eux, deux sont impliqués dans des formes sévères autosomiques récessives démyélinisantes, les CMT4B1 et CMT4B2. Ces gènes codent pour des protéines de la famille des myotubularines, MTMR2 et MTMR13. Les rôles cellulaires de ces protéines sont aujourd'hui encore largement inconnus. Nous avons étudié les profils d'expression de ces gènes et montré qu'ils s'expriment selon un profil spatio-temporel similaire, mais avec une cinétique différente lors de la myélinisation. Nous avons ensuite établi un modèle in vitro de leur perte de fonction par RNA interférence, et montré qu'elle entraîne une diminution de la densité des cellules de Schwann. De plus, l'inactivation de MTMR2 diminue la survie de ces cellules par un mécanisme apoptotique dépendant des caspasesThe Charcot Marie Tooth disease is the most common inherited neuropathy in humans, with a frequency of 1/2500. More than 20 genes have been identified so far, and two of them are involved in the severe autosomal recessives demyelinating forms CMT4B1 and CMT4B2. Those two genes belongs to the myotubularin family, MTMR2 (Myotubularin related 2) and MTMR13, their roles in the physiopathology of the CMT4 being still largely unknown. We established their expression profile during development and showed that they are spatially expressed in a similar way, but differ during the myelination. We then developed a model in which MTMR2 and MTMR13 loss of function was reproduced in Schwann cells by RNA interference. We found that depletion of MTMR2 and MTMR13 cells decreased their rate of proliferation. Furthemore, MTMR2-depletion increased the number of Schwann cells that died by a caspase-dependant apoptosis
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Asai, Keita. "Tooth Loss and Atherosclerosis: The Nagahama study." Kyoto University, 2015. http://hdl.handle.net/2433/202796.
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Robins, Robert R. "Tooth Engagement Evaluation of Involute Spline Couplings." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2605.pdf.
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De, Caires Brian J. "Variation Analysis of Involute Spline Tooth Contact." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/375.
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The purpose of this thesis is to provide an in-depth understanding of tooth engagement in splined couplings based on variations in clearances between mating teeth. It is standard practice to assume that 25-50% of the total spline teeth in a coupling are engaged due to variations from manufacture. Based on the assumed number of teeth engaged, the load capability of a splined coupling is determined. However, due to the variations in tooth geometry from manufacuture, the number of teeth actually engaged is dependent on the applied load and the tooth errors. The variations result in sequential tooth engagement with increasing load. To date, little work has been done to model tooth engagement and the stresses resulting from unequal load sharing among engaged teeth. A Statistical Tooth Engagement Model (STEM) has been developed which allows designers to estimate tooth engagement and resulting stress based on a statistical representation of the tooth errors. STEM is validated with finite element models as well as some preliminary experimental tests. Parametric studies are performed to determine the effect and sensitivities of variations in tooth parameters and tooth errors.