Thesis (M.S.)--University of Michigan, Ann Arbor, 1980. / Typescript (photocopy). Includes bibliographical references (leaves 57-59). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1980. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 57-59).

Thesis (M.S. in oral sciences)--University of Illinois at Chicago, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M. Sc.)--University of Manitoba, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S. in oral sciences)--University of Illinois at Chicago, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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

Made available in DSpace on 2014-06-11T19:27:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-27Bitstream added on 2014-06-13T19:36:11Z : No. of bitstreams: 1 sakima_cgp_me_arafo.pdf: 875892 bytes, checksum: 0b407b85b7e24386d401869c06430798 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A possibilidade de usar fios superelásticos retangulares com níveis de força mais leves (biológicos) permitiria simultâneo alinhamento, nivelamento e torque, o que resultaria em um menor número de fios utilizados, reduzindo custos e tempo de tratamento. Existe uma tendência, principalmente na ortodontia lingual, de se dobrar fios superelásticos (manualmente ou com tratamento térmico/elétrico) para adequar o fio à forma do arco. O objetivo deste trabalho foi avaliar as propriedades mecânicas de fios de NiTi de quatro marcas comerciais diferentes (0,017 x 0,025) após dobras e tratamento elétrico. Os fios foram dobrados com alicates elétricos (sistema DERHT) e com alicate 139 e depois foram comparados com fios retos sem nenhum tratamento (grupo controle) e fios retos com tratamento elétrico sem dobras (grupo controle tratamento elétrico). Na tentativa de simular uma situação clínica, todos os fios foram testados a 36oC na máquina de testes FSI (Sistema Identificador de Forças). Foram testados usando-se braquetes autoligáveis tipo Damon, simulando ativações em segunda ordem de 0 mm a 2 mm. Foram analisadas as seguintes variáveis: força e deslocamento no ponto do limite elástico, força máxima, energia total, energia dissipada, energia perdida, força e deslocamento no início e no fim do platô, inclinação e comprimento do platô. As diferenças estatísticas para os diferentes fios, nos diferentes testes, foram avaliadas pela ANOVA. Os resultados mostraram que: (1) o tratamento elétrico afetou as propriedades mecânicas de todos os fios de maneira geral, existindo uma tendência de diminuição nos níveis de força; (2) quando os fios receberam dobras, todos perderam os platôs de superelasticidade; (3) se o uso de forças leves e constantes é desejável no tratamento ortodôntico, os fios termodinâmicos deveriam ser recomendados na seguinte ordem: Copper NiTi 400, Neo Sentalloy 100 e Copper NiTi 270. / The possibility of using superelastic rectangular Nickel-Titanium wires in early stages of treatment with light forces, could allow more three-dimensional control, a small number of wires, lowering costs and treatment time. There is a tendency, especially in lingual orthodontics of bending superelastic wires (manually or with heat treatment) to adequate the wire in the arch anatomy. The aim of this study was to evaluate the mechanical properties of four commercially available 0.017 x 0.025 inch NiTi archwires after bending and heat treatment. The wires were bent with electrical pliers (DERHT System) and with standard bird beak plier and then compared with straight wires as a control group and another electrical treatment control group. All the wires were tested at 360 C in an orthodontic wire-testing device, a so called Force System Identification (FSI) apparatus. In the FSI a two-bracket system using self ligating Damon brackets simulated second order displacements up to 2 mm. The following variables from the activation/deactivation curves were calculated: force and displacement at yield point, maximum force level, total energy up to maximum displacement, energy loss after deactivation, force and displacement at the beginning and at finish of the plateau, and the slope and length of the plateau. Any statistically significant differences in these variables for the different brands and tests were analyzed using one-way analysis of variance. The results showed that: (1) the electrical treatment affected the characteristics of all the wires tested in a different way but with a tendency of lowering the force levels. (2) When the wires were bent they all lost activation and deactivation plateau of superelasticity. (3) If the use of low and constant force levels are desirable in orthodontic treatment, the thermodynamic wires should be recommended in the following order: Copper Niti 400 , NeoSentalloy 100 and Copper Niti 270.

Indiana University-Purdue University Indianapolis (IUPUI) / This investigation was designed to compare the force (grams) required to overcome a simulated cuspid retraction assembly capable of three dimensional control during the retraction process. It was hypothesized that a significant difference in the mean retraction values exists between the newer orthodontic alloys of Nitinol, Beta-Titanium, as well as Stainless Steel. One hundred eighty bracket and archwire combinations were examined as follows: Sample # Wire Cross-section Wire Material 30 .016”x.022” Stainless Steel 30 .017”x.025” ” 30 .016”x.022” Nitinol 30 .017”x.025” ” 30 .016”x.022 Beta-Titanium (TMA) 30 .017”x.025” ” A statistically significant difference was shown to exist between all six groups examined regarding the variables of wire size and wire material. The statistical analysis revealed that increasing rectangular archwire cross-sectional size from .016"x.022" to .017"x.025” rectangular wire when simulating canine retraction using an .018" slotted Lewis bracket will lead to significantly greater functional forces. The analysis of wire materials indicated that a significant difference (p=.01) exists between rectangular Beta-Titanium (TMA), Nitinol, and stainless steel during simulated cuspid retraction utilizing a narrow .018" Lewis bracket ligated with A-lastik ligatures. The least frictional force was observed with the .016"x.022" stainless steel test cells. The largest frictional force was found in the .017”'x.025" Beta-Titanium retraction specimens. Nitinol revealed force data intermediate between stainless steel and Beta-Titanium. The maximum resistance assembly developed 2.3 times the minimum frictional force observed. The mean grams of frictional force within these test cells ranged from 55.03 grams for the .016"x.022" retraction assembly to 132.68 grams for the .017"x.025" Beta-Titanium assembly. A topographical scanning electron microscope survey of the brackets and archwires utilized was included to provide qualitative insights into the quantitative results described.

Indiana University-Purdue University Indianapolis (IUPUI) / The present study was designed to test the tensile bond strength of two new bracket base designs and compare the results with those of the study by Higgins using Ormesh brackets. It was hypothesized that the visible increase in surface roughness of the two new bracket bases over the conventional (Ormesh) mesh would increase the tensile bond strength of the bracket. Sixteen DuraLingual mesh brackets and the acid-etched bracket bases were fabricated and bonded to human maxillary bicuspid teeth with a Bis-GMA compound adhesive as described by Higgins. After 24 hours, the bases were subjected to tensile bond strength testing until failure in tension and 10 brackets tested from each group were used to calculate the results. The following results were recorded: (1) The mean tensile bond strength of DuraLingual mesh and acid-etched bracket bases were significantly greater than the Ormesh wire mesh. (2) The mean tensile bond strength of the acid-etched base was significantly greater than the DuraLingual mesh. The visually apparent surface roughness and intricate microscopic voids and pits created by electrolytically-etching a smooth bracket base surface may have contributed to greater mechanical retention in this bracket compared to a smooth wire mesh bracket base (Ormesh) and a cast mesh (DuraLingual).

Orientador: João Roberto Gonçalves / Banca: Cyneu Aguiar Pansani / Banca: Arno Locks / Resumo: A possibilidade de usar fios superelásticos retangulares com níveis de força mais leves (biológicos) permitiria simultâneo alinhamento, nivelamento e torque, o que resultaria em um menor número de fios utilizados, reduzindo custos e tempo de tratamento. Existe uma tendência, principalmente na ortodontia lingual, de se dobrar fios superelásticos (manualmente ou com tratamento térmico/elétrico) para adequar o fio à forma do arco. O objetivo deste trabalho foi avaliar as propriedades mecânicas de fios de NiTi de quatro marcas comerciais diferentes (0,017" x 0,025") após dobras e tratamento elétrico. Os fios foram dobrados com alicates elétricos (sistema DERHT) e com alicate 139 e depois foram comparados com fios retos sem nenhum tratamento (grupo controle) e fios retos com tratamento elétrico sem dobras (grupo controle tratamento elétrico). Na tentativa de simular uma situação clínica, todos os fios foram testados a 36oC na máquina de testes FSI (Sistema Identificador de Forças). Foram testados usando-se braquetes autoligáveis tipo Damon, simulando ativações em segunda ordem de 0 mm a 2 mm. Foram analisadas as seguintes variáveis: força e deslocamento no ponto do limite elástico, força máxima, energia total, energia dissipada, energia perdida, força e deslocamento no início e no fim do platô, inclinação e comprimento do platô. As diferenças estatísticas para os diferentes fios, nos diferentes testes, foram avaliadas pela ANOVA. Os resultados mostraram que: (1) o tratamento elétrico afetou as propriedades mecânicas de todos os fios de maneira geral, existindo uma tendência de diminuição nos níveis de força; (2) quando os fios receberam dobras, todos perderam os platôs de superelasticidade; (3) se o uso de forças leves e constantes é desejável no tratamento ortodôntico, os fios termodinâmicos deveriam ser recomendados na seguinte ordem: Copper NiTi 400, Neo Sentalloy 100 e Copper NiTi 270. / Abstract: The possibility of using superelastic rectangular Nickel-Titanium wires in early stages of treatment with light forces, could allow more three-dimensional control, a small number of wires, lowering costs and treatment time. There is a tendency, especially in lingual orthodontics of bending superelastic wires (manually or with heat treatment) to adequate the wire in the arch anatomy. The aim of this study was to evaluate the mechanical properties of four commercially available 0.017 x 0.025 inch NiTi archwires after bending and heat treatment. The wires were bent with electrical pliers (DERHT System) and with standard bird beak plier and then compared with straight wires as a control group and another electrical treatment control group. All the wires were tested at 360 C in an orthodontic wire-testing device, a so called Force System Identification (FSI) apparatus. In the FSI a two-bracket system using self ligating Damon brackets simulated second order displacements up to 2 mm. The following variables from the activation/deactivation curves were calculated: force and displacement at yield point, maximum force level, total energy up to maximum displacement, energy loss after deactivation, force and displacement at the beginning and at finish of the plateau, and the slope and length of the plateau. Any statistically significant differences in these variables for the different brands and tests were analyzed using one-way analysis of variance. The results showed that: (1) the electrical treatment affected the characteristics of all the wires tested in a different way but with a tendency of lowering the force levels. (2) When the wires were bent they all lost activation and deactivation plateau of superelasticity. (3) If the use of low and constant force levels are desirable in orthodontic treatment, the thermodynamic wires should be recommended in the following order: Copper Niti 400 , NeoSentalloy 100 and Copper Niti 270. / Mestre