This study was conducted to see the effect of TiN ion-plating on the bond strength of orthodontic bracket. Three stainlesssteel brackets with different base types were chosen; when TiNTion-plated brackets and non ion-plated brackets were bonded to the teeth, initial and long-term bond strength were measured The observations of bonding surface and failure sites through the scanning electron microscope were analysed and compared.
The summary of this study was as follows:
When TiN ion-plating was not applied, the Micro-Loc type was the highest in bond strength atter 24 hours as 5.89±1.77 MPa, followed by 4.27±1.12 MPa for Foil Mesh type and 2.64±0.58 MPa for Undercut type(P<0.05).
Under TiN ion-plating, the bond strength after 24 hours showed: Micro-Loc type - 6.26±1.51 MPa, Foil Mesh type - 7.45± 2.01 MPa, Undercut type - 2.93±0.84 MPa Unlike in the case of non ion-plating, Foil Mesh type showed a higher strength than Micro-Loc type, with Undercut type still showing the lowest bond strength(P<0.05).
The bond strength, after 24 hours, increased in case of ion-plated in all 3 types, but a significant increase was shown only in Foil Mesh type(P<0.001).
Under a long-term immersion, regardless of ion or non ion-plating, bond strength in general increased over the initial bond strength(one day), with more stability.
Through scanning electron microscopic observation of bonding surface, it was found that, regardless of the bracket base type
or the application of ion-plating, the resin was thoroughly spreaded into bracket base to form a solid bonding surface between
the bracket and the tooth.. This was also true in case of a long-term immersion.
The scanning electron microscopic observation of failure sites revealed diverse failure patterns.
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