Magister Chirurgiae Dentium - MChD (Orthodontics) / The aim of the study is to compare the frictional resistance generated between two types of self-ligating brackets; Smart-Clip Metal SL (3M Unitek) and Damon Clear SL (Ormco), with conventional stainless steel brackets, Victory Series (3M Unitek) when coupled with various stainless steel and nickel-titanium archwires. Materials and Methods: All brackets had a 0.022" slot and tested using three archwires: 0.016" nickel-titanium, 0.019 x 0.025" nickel-titanium and 0.019 x 0.025" stainless steel archwires. Friction was evaluated for the upper right quadrant of the typodont. For each testing procedure, new brackets and archwire was employed to eliminate the influence of wear. Results: The mean results showed that the Smart-Clip self-ligating brackets generated significantly lower friction than both the Damon Clear self-ligating brackets and Victory Series brackets. However, the analysis of the various bracket-archwire combinations displayed that Damon Clear SL brackets generated the lowest friction when tested with 0.016" round nickeltitanium archwire and significantly higher friction than Smart-Clip and Victory Series brackets when tested with 0.019 x 0.025" stainless steel rectangular archwires. All brackets showed higher frictional forces as the wire size increased. Clinical relevance: The production of high levels of friction during orthodontic sliding mechanics presents a clinical challenge to the orthodontists. The generation of high levels of friction may reduce the effectiveness of the mechanics, decrease tooth movement efficiency and further complicate anchorage control. The amount of friction is variable in the orthodontic system and can be altered somewhat by the orthodontist's choices.

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Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-08-29T18:10:51Z No. of bitstreams: 2 Dissertação - Vinícius Marcelo Aires Póvoa - 2011.pdf: 2752370 bytes, checksum: 9fbffc261c22bdc57a1b99d2aed34d3e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2016-08-29T18:12:36Z (GMT) No. of bitstreams: 2 Dissertação - Vinícius Marcelo Aires Póvoa - 2011.pdf: 2752370 bytes, checksum: 9fbffc261c22bdc57a1b99d2aed34d3e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-29T18:12:36Z (GMT). No. of bitstreams: 2 Dissertação - Vinícius Marcelo Aires Póvoa - 2011.pdf: 2752370 bytes, checksum: 9fbffc261c22bdc57a1b99d2aed34d3e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2011-12-21 / Flexy-Multi™, a newly introduced finishing wire with the outermost portion of its crosssection composed by nickel-titanium and its core by beta-titanium, was evaluated according to its flexural behavior in bending tests. The aim of this study was to compare the loaddeflection rate of Flexy-Multi™ to stainless-steel, beta titanium and nickel-titanium archwires in three-point bending test. The samples examined included 0.017”x 0.025”-inch stainlesssteel, beta-titanium, nickel-titanium and Flexy-Multi™ wires. Each combination, alloy and manufacturer, was tested 6 times and an average was obtained for comparison. All specimens were tested in a universal testing machine (EMIC DL10.000/700) in a 3-point bending test at a speed of 1mm per minute and deflected for 1.5 mm. Loading and unloading forces were recorded at each 0.5mm of deflection and load-deflection curves were determined. Three self-ligating brackets of lower incisors (In-Ovation – GAC Orthodontics, Roth prescription, slot .022”x.028”) were used as supports to the wires. On loading, there was no difference between Flexy-Multi™ and all nickel-titanium wires tested. On the other hand, Flexy-Multi™ showed lower load-deflection rates than all stainless-steel and betatitanium wires both on loading and unloading (p>0.05). On unloading, Flexy-Multi™ showed lower load-deflection rate than all nickel-titanium wires just to 0.5mm of deflection (p<0.05). Flexy-multi™ presented a lower load-deflection rate than all wires tested, except when compared to nickel-titanium where this difference came up just at the level of 0.5mm of unloading, since this wire lost force by the end of the test. / O Flexy-Multi®, fio recentemente introduzido ao mercado brasileiro, composto por uma camada externa de níquel-titânio e um núcleo central de beta-titânio, foi avaliado de acordo com o seu comportamento mecânico em testes de flexão. O objetivo do presente trabalho foi comparar a proporção carga/deflexão do Flexy-Multi® com fios de aço, beta-titânio e níquel-titânio em testes de flexão em três bráquetes. As amostras avaliadas constituíam-se de fios 0,017” x 0,025” de aço, beta-titânio, níquel-titânio e o Flexy-Multi®. Cada combinação, liga e fabricante, foi testada 6 vezes e médias foram obtidas para comparação. Todos os espécimes foram submetidos a ensaios de flexão em três pontos em máquina universal de ensaio EMIC DL10.000/700, utilizando bráquetes autoligados de incisivos inferiores (In-Ovation, slot 0,022” x 0,028” e prescrição Roth) como suportes. A velocidade dos ensaios foi de 1mm/min com deflexão máxima de 1,5mm. Forças de ativação e desativação foram registradas a cada 0,5mm e curvas carga x deflexão estabelecidas. Na ativação, não houve diferença entre o Flexy-Multi® e os demais fios de níquel-titânio testados. Por outro lado, o Flexy-Multi® mostrou menor proporção carga/deflexão que todos os fios de aço e beta-titânio, tanto na ativação quanto na desativação (p>0,05). Na desativação, o Flexy-Multi® mostrou menor proporção carga-deflexão que todos os fios de níquel-titânio testados apenas para 0,5mm de deflexão (p<0,05). O Flexy-Multi® apresentou menor proporção carga-deflexão que todos fios testados, exceto quando comparado aos fios de níquel-titânio, já que neste caso esta diferença se evidenciou apenas para 0,5mm de deflexão na desativação, evidenciando uma perda de força deste fio ao final do teste.

Objectif : il a été rapporté que l’utilisation d’agents prophylactiques fluorés pouvait favoriser la corrosion galvanique au sein des alliages de titane. L’objectif de la présente étude était d’évaluer l’effet d’un rince-bouche fluoré sur les propriétés mécaniques de fils en nickel-titane (NiTi) et de fils en cuivre-nickel-titane (CuNiTi) lorsque ces derniers sont couplés à des boîtiers de compositions différentes (boîtiers de marques Smartclip, Clarity, et Sprint). Matériels et Méthodes : 90 segments de fils en NiTi et 90 segments de fils en CuNiTi ont été chacun couplés à 2 boîtiers de chaque marque. Chaque assemblage fil-boîtiers a été par la suite incubé pendant 3 heures à 37°C, soit dans une solution de fluore neutre (Fluorinse™ 0,05% NaF), soit dans une solution de salive artificielle (solution contrôle). Suite à l’incubation, les échantillons étaient nettoyés avec de l’eau déshydrogénée, les fils séparés des boîtiers et montés sur un support pour subir un test de pliage en trois points en milieu humide (salive artificielle) à 37°C. Les modules d’élasticité ainsi que les limites conventionnelles d’élasticité en activation et en désactivation ont été mesurés et comparés. Des analyses de Variance (ANOVA) et des comparaisons post-hoc avec la correction de Bonferronni ont été utilisées pour comparer les groupes entre eux (α = 0,05). Résultats : L’utilisation d’un rince-bouche fluoré a produit une réduction du module d’élasticité et de la limite conventionnelle d’élasticité en activation et en désactivation pour les fils en NiTi ; cependant, cet effet a été modulé par le type de boîtier auquel le fil a été couplé. Les propriétés mécaniques de fils en CuNiTi n’ont pas été affectées par le fluor, ou par le type de boîtier utilisé. Conclusions : L’utilisation d’un rince-bouche fluoré modifie les propriétés mécaniques des fils en NiTi seulement. Cet effet est modulé par le boîtier auquel le fil en NiTi est couplé. A la différence des autres études publiées dans la littérature, nos résultats ne nous permettent pas de conclure que la modification des propriétés mécaniques des fils en NiTi entrainerait obligatoirement un allongement de la durée du traitement orthodontique. Mots clés : Fluor, fils nickel-titane, boîtiers orthodontiques, corrosion galvanique, propriétés mécaniques. / Aim: it has been reported that the use of fluoride prophylactic agents can cause galvanic corrosion of the titanium based alloys used in orthodontics. The purpose of the present study was to investigate the effects of a fluoride mouthrinse on the mechanical properties of nickel-titanium (NiTi) and copper–nickel-titanium (CuNiTi) orthodontic archwires that have been coupled with different types of orthodontic brackets (Smartclip, Clarity, and Sprint brackets). Materials and Methods: 90 segments of NiTi and 90 segments of CuNiTi archwires were tested. Every segment was coupled with 2 brackets of each brand. The wire–bracket assembly obtained was incubated, at 37°C for three hours either in a solution of a commercially available mouthwash (Fluorinse™ 0,05% NaF), or in a solution of artificial saliva (control). Following the incubation, the wires were separated from the brackets, rinsed, mounted on a stainless steel support and placed in a waterbath of artificial saliva at 37°C. A 3-point bending test was made to calculate the loading and unloading elastic modulus and yield strength of the wires. Analysis of variance (ANOVA) and post hoc comparisons were made using Bonferronni’s correction to identify the statistically significant differences (α = 0,05). Results: The use of a fluoridated mouthrinse reduced the loading and unloading elastic modulus and yield strength of the NiTi wires. This reduction, however, varies with the type of bracket that was coupled with the wire. The mechanical properties of the CuNiTi wires were not modified by the use of the fluoride rinse or by the type of bracket to which they were coupled. Conclusions : The use of a fluoride mouthrinse alters the mechanical properties of NiTi wires only. This effect varies with the type of bracket that was in contact with the wire. However our results do not allow us to conclude that the alteration of the mechanical properties of the wires would necessarily imply a prolongation of the orthodontic treatment time. Key words: Fluoride, nickel-titanium archwires, galvanic corrosion, mechanical properties,orthodontic brackets.

Objectif : il a été rapporté que l’utilisation d’agents prophylactiques fluorés pouvait favoriser la corrosion galvanique au sein des alliages de titane. L’objectif de la présente étude était d’évaluer l’effet d’un rince-bouche fluoré sur les propriétés mécaniques de fils en nickel-titane (NiTi) et de fils en cuivre-nickel-titane (CuNiTi) lorsque ces derniers sont couplés à des boîtiers de compositions différentes (boîtiers de marques Smartclip, Clarity, et Sprint). Matériels et Méthodes : 90 segments de fils en NiTi et 90 segments de fils en CuNiTi ont été chacun couplés à 2 boîtiers de chaque marque. Chaque assemblage fil-boîtiers a été par la suite incubé pendant 3 heures à 37°C, soit dans une solution de fluore neutre (Fluorinse™ 0,05% NaF), soit dans une solution de salive artificielle (solution contrôle). Suite à l’incubation, les échantillons étaient nettoyés avec de l’eau déshydrogénée, les fils séparés des boîtiers et montés sur un support pour subir un test de pliage en trois points en milieu humide (salive artificielle) à 37°C. Les modules d’élasticité ainsi que les limites conventionnelles d’élasticité en activation et en désactivation ont été mesurés et comparés. Des analyses de Variance (ANOVA) et des comparaisons post-hoc avec la correction de Bonferronni ont été utilisées pour comparer les groupes entre eux (α = 0,05). Résultats : L’utilisation d’un rince-bouche fluoré a produit une réduction du module d’élasticité et de la limite conventionnelle d’élasticité en activation et en désactivation pour les fils en NiTi ; cependant, cet effet a été modulé par le type de boîtier auquel le fil a été couplé. Les propriétés mécaniques de fils en CuNiTi n’ont pas été affectées par le fluor, ou par le type de boîtier utilisé. Conclusions : L’utilisation d’un rince-bouche fluoré modifie les propriétés mécaniques des fils en NiTi seulement. Cet effet est modulé par le boîtier auquel le fil en NiTi est couplé. A la différence des autres études publiées dans la littérature, nos résultats ne nous permettent pas de conclure que la modification des propriétés mécaniques des fils en NiTi entrainerait obligatoirement un allongement de la durée du traitement orthodontique. Mots clés : Fluor, fils nickel-titane, boîtiers orthodontiques, corrosion galvanique, propriétés mécaniques. / Aim: it has been reported that the use of fluoride prophylactic agents can cause galvanic corrosion of the titanium based alloys used in orthodontics. The purpose of the present study was to investigate the effects of a fluoride mouthrinse on the mechanical properties of nickel-titanium (NiTi) and copper–nickel-titanium (CuNiTi) orthodontic archwires that have been coupled with different types of orthodontic brackets (Smartclip, Clarity, and Sprint brackets). Materials and Methods: 90 segments of NiTi and 90 segments of CuNiTi archwires were tested. Every segment was coupled with 2 brackets of each brand. The wire–bracket assembly obtained was incubated, at 37°C for three hours either in a solution of a commercially available mouthwash (Fluorinse™ 0,05% NaF), or in a solution of artificial saliva (control). Following the incubation, the wires were separated from the brackets, rinsed, mounted on a stainless steel support and placed in a waterbath of artificial saliva at 37°C. A 3-point bending test was made to calculate the loading and unloading elastic modulus and yield strength of the wires. Analysis of variance (ANOVA) and post hoc comparisons were made using Bonferronni’s correction to identify the statistically significant differences (α = 0,05). Results: The use of a fluoridated mouthrinse reduced the loading and unloading elastic modulus and yield strength of the NiTi wires. This reduction, however, varies with the type of bracket that was coupled with the wire. The mechanical properties of the CuNiTi wires were not modified by the use of the fluoride rinse or by the type of bracket to which they were coupled. Conclusions : The use of a fluoride mouthrinse alters the mechanical properties of NiTi wires only. This effect varies with the type of bracket that was in contact with the wire. However our results do not allow us to conclude that the alteration of the mechanical properties of the wires would necessarily imply a prolongation of the orthodontic treatment time. Key words: Fluoride, nickel-titanium archwires, galvanic corrosion, mechanical properties,orthodontic brackets.