Morphological and Structural Characterization of Two Types of As-Received and In vivo Orthodontic Stainless Steel Brackets

Aims: To perform a) a topographical analysis of the bracket slot of 12 as-received stainless steel brackets and of in vivo used stainless steel brackets from 7 patients and b) a compositional characterization of the constituting materials of two types of brackets.
Study Design: In vitro laboratory study.
Methodology: 12 as-received brackets and in vivo used brackets of seven patients were analysed. Two commercially available brackets were used for this study. A SEM analysis evaluated the topographic features of each bracket slot while an EDAX analysis was performed to analyse the constituting parts of each bracket.
Results: As-received ORMCO brackets show more traces of plastic deformation than GAC brackets. On the contrary, pits, crevices and grain boundaries were observed on all as-received brackets. An increased plastic deformation and amount of scratches was noticed on ORMCO and GAC brackets after orthodontic treatment. Elemental analysis revealed that base and wing materials were not identical in GAC nor in Ormco brackets. In addition, both ORMCO and GAC brackets consist each of two parts assembled using a different brazing material.
Conclusion: Both as-received brackets show different damage patterns on their slot surface. Increase of damage patterns was visualized after intra-oral use. As a consequence of the use of different constituting materials for the manufacturing of the two types of brackets investigated, galvanic corrosion is likely to occur.