Thesis (M.S.)--University of Michigan, 1991.

Thesis (Ph. D.)--University of Alabama at Birmingham, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1991.

Thesis (M.S.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains viii, 49 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 41-48).

Thesis (M. Sc.)--University of Toronto, 1996. / Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2001. / Includes bibliographical references.

Thesis (Ph. D.)--Rensselaer Polytechnic Institute, Troy, New York, 1992. / Includes bibliographical references (p. 184-200).

Made available in DSpace on 2014-06-11T19:35:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-31Bitstream added on 2014-06-13T20:25:51Z : No. of bitstreams: 1 barao_var_dr_araca.pdf: 1603640 bytes, checksum: 5d48588f784413a0d8cc560b1ff6d9b0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivos: (1) Investigar o papel de diferentes níveis de pH da saliva artificial (3; 6,5 e 9) no comportamento corrosivo do titânio comercialmente puro (cp-Ti) e da liga Ti-6Al-4V (Capítulo 1); (2) Avaliar a influência do processo de corrosão na afinidade do lipopolissacarídeo (LPS) de Escherichia coli para o cp-Ti e o Ti-6Al-4V (Capítulo 2); (3) Investigar a natureza tribocorrosiva do titânio em saliva artificial em presença de LPS (Capítulo 3); (4) Comparar o efeito de diferentes designs de overdentures implanto-retidas e prótese total fixa implanto-suportada na distribuição de tensões em mandíbula edêntula pelo método de elementos finitos tridimensional (Capítulo 4). Materiais e métodos: Testes eletroquímicos como potencial de circuito aberto, espectroscopia de impedância eletroquímica, e teste potenciodinâmico foram conduzidos. Para o teste de afinidade ao LPS, os espécimes foram tratados com LPS (1,5; 15 e 150 μg/ml) durante 24 horas para avaliar a aderência de LPS. Os discos foram transferidos a cada 24 horas para solução fresca de água livre de LPS até completar 72 horas, para investigar a liberação de LPS. No teste de tribocorrosão, o pH da saliva (6,5), a concentração de LPS (0, 0,15, 15 and 150 μg/ml), a duração do deslizamento (2000 ciclos), freqüência (1,2 Hz) e carga (20 N) foram usados para mimetizar o processo mastigatório. Finalmente, modelos tridimensionais de uma mandíbula edêntula foram construídos. No grupo OR a mandíbula foi restaurada com overdenture retida por implantes não esplitados com sistema de retenção O’ring; nos grupos BC-C e BC as mandíbulas foram restauradas com overdentures retidas por implantes esplintados com sistema de retenção barra-clipe associado ou não a cantilevers distais... / Objectives: (1) To investigate the role of different levels of pH of artificial saliva (pHs 3, 6.5 and 9) under simulated oral environment on the corrosion behavior of commercially-pure titanium (cp-Ti) and Ti-6Al-4V alloy (Chapter 1); (2) To assess the influence of corrosion process on Escherichia coli lipopolysaccharide (LPS) affinity for cp-Ti and Ti-6Al-4V alloy (Chapter 2); (3) To evaluate the tribocorrosive (corrosion/wear) nature of titanium in artificial saliva (pH 6.5) with LPS (Chapter 3); and (4) To compare the effect of different designs of implant-retained overdentures and fixed full-arch implant-supported prosthesis on stress distribution in edentulous mandible by using a three-dimensional finite element analysis. Materials and methods: Standard electrochemical tests, such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic tests were conducted in a controlled environment. For LPS affinity test, specimens were treated with LPS (1.5, 15 and 150 μg/ml) for 24 hours to evaluated LPS adherence. Discs were then transferred every 24 hours to fresh LPS-free water, up to 72 hours, to investigate LPS elution. In the tribocorrosion test, the pH of saliva (6.5); LPS concentration (0, 0.15, 15 and 150 μg/ml), sliding duration (2000 cycles), frequency (1.2Hz) and load (20 N) parameters mimicked the mastication process. Finally, tridimensional models of an edentulous mandible were constructed. In the OR group, the mandible was restored with an overdenture retained by unsplinted implants with O’ring attachment; in the BC-C and BC groups, the mandibles were restored with overdentures retained by splinted implants with bar-clip anchor associated or not with distally placed cantilevers, respectively; in the FD group, the mandible was restored with a fixed full-arch implant-supported prosthesis... (Complete abstract click electronic access below)

This thesis relates to the feasibility of monitoring dental implants using the transmission of Acoustic Emission (AE) from an intra-oral source to a sensor mounted on the patient’s face. A number of in vitro and in vivo experiments have been carried using different AE sources on teeth and dental implants with the ultimate aim of defining the characteristics of the AE signatures in the time- and frequency-domains that are affected by the implant-bone interface. An initial feasibility study was carried out to assess the transmission of simulated AE signals through human teeth and hard and soft tissues by biting on different types of hard food. The tests demonstrated that the transmission of AE signals through human tissues was feasible. However, the source was not reproducible. Further preliminary experiments were carried out to assess the transmission of AE in various dental materials as well as in bone and bone-implant combinations in various states of hydration. The main systematic body of work centred around establishing whether AE signals could discriminate between implants with different amounts of contact with bone. AE signals were generated by applying a standard impulse source through a specially-designed abutment onto dental implants of various sizes (large and small) inserted in bovine ribs under tight and loose fitting conditions. The findings suggested that this simple transmission test was able to assess the quality of the contact between the implant and the bone in the in vitro situation and that it might be possible to extend this to the clinical environment. The (standard) pencil lead break method was not suitable for use intra-orally, so a more suitable source for in vivo testing needed to be developed. After considering various options a continuous source (based on an air jet) was developed and this was applied to dental implants in the same set of systematic tests as for the pencil lead source. The analysis revealed that the air jet source was a little better at discriminating between the various implant contact conditions. Finally, an in vivo study was conducted to assess the characteristics of the transmitted AE form air jet source applied to the dental implants of a number of volunteers. The findings demonstrated that the AE transmission through the implants, soft and hard tissues using an air jet source was feasible, with the degree of transmission depending on a number of variables, some related to the patients themselves and some related to other, tractable engineering factors. The overall conclusion of the work is that the technique is very likely to be successful for monitoring implant stability, and is feasible to apply with minimum invasion to patients whose implants have been newly installed. An in vivo study in which the test is applied to patients during the stages of stabilisation of their implants is required in order to validate the technique.