Physical and chemical properties of orthodontic brackets after 12 and 24
months: in situ study |
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| Authors: | Bernardo de Azevedo Bahia MENDES Ricardo Alberto Neto FERREIRA Matheus Melo PITHON Martinho Campolina Rebello HORTA Dauro Douglas OLIVEIRA |
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| Affiliation: | 1. Graduate Program in Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte, MG, Brazil.;2. Center for Development of Nuclear Technology, National Nuclear Energy Commission CDTN/CNEN, Belo Horizonte, MG, Brazil.;3. Department of Orthodontics, Southwest Bahia State University - UESB, Jequié, BA, Brazil. |
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| Abstract: | ObjectiveThe aim of this article was to assess how intraoral biodegradation influenced thesurface characteristics and friction levels of metallic brackets used during 12and 24 months of orthodontic treatment and also to compare the static frictiongenerated in these brackets with four different methods of the ligation oforthodontic wires.Material and MethodsSeventy premolar brackets as received from the manufacturer and 224 brackets thatwere used in previous orthodontic treatments were evaluated in this experiment.The surface morphology and the composition of the deposits found in the bracketswere evaluated with rugosimetry, scanning electron microscopy, and energydispersive X-ray spectroscopy. Friction was analyzed by applying tensile testssimulating sliding mechanics with a 0.019x0.025" steel wire. The static frictionlevels produced by the following ligation methods were evaluated: loosely attachedsteel ligature around all four bracket wings, steel ligature attached to only twowings, conventional elastomeric ligation around all 4 bracket wings, andnon-conventional Slide® elastomeric ligature.ResultsThe results demonstrated the presence of biodegradation effects such as corrosionpits, plastic deformation, cracks, and material deposits. The main chemicalelements found on these deposits were Carbon and Oxygen. The maximum frictionproduced by each ligation method changed according to the time of intraoral use.The steel ligature loosely attached to all four bracket wings produced the lowestfriction levels in the new brackets. The conventional elastic ligatures generatedthe highest friction levels. The metallic brackets underwent significantdegradation during orthodontic treatment, showing an increase in surface roughnessand the deposit of chemical elements on the surface.ConclusionThe levels of static friction decreased with use. The non-conventional elasticligatures were the best alternative to reduce friction. |
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| Keywords: | Orthodontic brackets Friction Biodegradation |
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