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Previous issue date: 2018-01-24 === Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES === Objective: Quantify the metal ion release of different brazing and welding methods in
the saliva of patients that need a lingual arch appliance and evaluate the surfaces of
soldered and welded bands in scanning el?ctron microscopy (SEM). Material and
Methods: 64 patients were selected and distributed into four groups: Group 1 (21
patients that did not need a lingual arch), group 2 (16 patients that needed a lingual
arch and had the appliance manufactured with the silver solder brazing method),
group 3 (14 patients that needed a lingual arch and had the appliance manufactured
with the laser welding method) and group 4 (13 patients that needed a lingual arch
and had the appliance manufactured with the TIG welding method). Saliva samples
were collected at different points in time (before treatment, 7 days after placing
appliance, 15 days after placing appliance and 30 days after placing appliance) and
were analyzed with an ICP mass spectrometer followed by generalized estimating
equation modeling with a 5% level of significance. In addition, 9 bands with steel
joints were evaluated in SEM to compare the surface of the 3 different joining
techniques (brazing, laser welding and TIG welding). Results: For ions Cr, Fe, Cu
and Sn comparing concentrations between groups, there was no difference in the
variation along the collections and there was no statistically significant difference
throughout the collections for any of the groups when comparing these ions
concentrations. For Ni, values were compared in groups and at points in time, and an
interaction effect was seen (P<0.001). For Zn, Ag, and Cd there was no difference
along the points in time. For Zn there was statistic difference from group 4 to groups
1 and 2; for Ag there was statistic difference from group 4 to groups 2 and 3. For Cd
there was statistic difference from T1 for T4 in all groups. Digital images were
generated and showed different surface characteristics. Brazing presented a flatter
and smoother area, while laser and TIG welding developed rougher areas.
Conclusions: Orthodontics appliances may affect salivary ion concentrations in vivo
over the short term evaluated. For most ions evaluated there was no increasing
significant release comparing types of soldering/welding and comparing values
throughout the points in time at the same group. Levels resembled those already
documented and remained below the daily dietary metals intake. Nevertheless, small
amounts of metal ions are able to induce allergic reactions and should be
considered. The protocol performed for conventional welding, together with a suitable
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finishing and polishing, guarantees a more regular welded ring surface. The protocols
for laser and TIG welding still have undefined aspects, and the need for filling
material must be evaluated to cover irregularities and prevent failures. === Objetivo: Avaliar e quantificar a presen?a de ?ons met?licos na saliva de pacientes
em uso de arco lingual com diferentes tipos de soldagem e avaliar as superf?cies de
an?is soldados por diferentes t?cnicas em microscopia eletr?nica de varredura
(MEV). Material e M?todo: 64 pacientes foram selecionados e distribu?dos em
quatro grupos: grupo 1 (21 pacientes sem necessidade de uso de arco lingual),
grupo 2 (16 pacientes em uso de arco lingual, sendo o aparelho fabricado pelo
m?todo de soldagem a prata), grupo 3 (14 pacientes em uso de arco lingual, sendo o
aparelho fabricado pelo m?todo de soldagem a laser) e grupo 4 (13 pacientes em
uso de arco lingual, sendo o aparelho fabricado pelo m?todo de soldagem TIG).
Amostras de saliva foram coletadas em diferentes tempos (inicial ? sem aparelho, 7,
15 dias e 30 dias ap?s a coloca??o do aparelho) e foram analisadas em ICP-MS
seguido de an?lise estat?stica para compara??o pelo modelo de equa??es de
estimativas generalizadas com n?vel de signific?ncia de 5%. Al?m disso, 9 an?is com
fios de a?o soldados foram avaliados em MEV para comparar as t?cnicas de
soldagem a prata, soldagem a laser e soldagem a TIG em rela??o ? superf?cie.
Resultados: Para as concentra??es de ?ons Cr, Fe, Cu e Sn comparadas entre os
grupos, n?o houve diferen?a na varia??o ao longo das cole??es e n?o houve
diferen?a estatisticamente significativa ao longo das coletas para os grupos. Para Ni,
os valores foram comparados em grupos e tempos de coleta, encontrando um efeito
de intera??o (P<0,001). Para Zn, Ag, e Cd, n?o houve diferen?a ao longo dos pontos
no tempo. Para Zn houve diferen?a estat?stica do grupo 4 para os grupos 1 e 2; Para
Ag houve diferen?a estat?stica do grupo 4 para os grupos 2 e 3. Para Cd houve
diferen?a estat?stica de T1 para T4 em todos os grupos. Imagens digitais
apresentaram caracter?sticas de superf?cie diferentes para cada m?todo de
soldagem testado. A solda de prata apresentou uma ?rea mais lisa e suave,
enquanto a soldagem a laser e a TIG desenvolveu ?reas mais irregulares.
Conclus?es: Aparelhos ortod?nticos podem afetar as concentra??es de ?ons em um
curto per?odo de avalia??o. Para a maioria dos ?ons avaliados, n?o houve aumento
significativo na libera??o comparando tipos de solda e comparando valores em todos
os pontos no mesmo grupo. Os n?veis se assemelham aos j? publicados na literatura
e est?o abaixo dos limites para ingest?o di?ria na dieta. No entanto, pequenas
quantidades de ?ons met?licos s?o capazes de induzir rea??es al?rgicas e devem
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ser consideradas. O protocolo realizado para soldagem convencional, juntamente
com acabamento e polimento adequados, garante uma superf?cie mais regular. Os
protocolos para soldagem laser e TIG ainda possuem aspectos indefinidos e a
necessidade de material de preenchimento deve ser avaliada para cobrir
irregularidades e evitar falhas.
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