engleski

Influence of aesthetic rhodium coating of nickel-titanium wires on their surface rougness and elastic behaviour in interaction with enamel remineralisation agents

Aim: The aim was to explore influence of topical enamel remineralisation agents based on sodium fluoride (Mirafluor) and casein phosphopeptide-amorphous calcium phosphate with sodium fluoride (MI Paste Plus) on surface roughness and elastic behaviour of non-aesthetic uncoated nickel-titanium (NiTi) and aesthetic rhodium coated NiTi wires (Rh-NiTi). Materials and method: Specimens of uncoated NiTi and Rh-NiTi BioForce Sentalloy (Dentsply GAC Int., NY, USA) 25×0.508×0.508 mm were immersed in Mirafluor (Hager&Werken, Duisburg, Germany), MI Paste Plus (GC, Tokyo, Japan) and dH2O (control) for 1 hour at 37°C. Loading and unloading elastic modulus (E) and yield strength (YS) of ten samples from each group were measured with a 3-point bending test by using Texture analyser TA.HD.plus (Stable Micro System, Godalming, UK) before and after exposure to tested agents in a thermal chamber at 37°C. Surface roughness was measured using Stylus instrument Perthometer S8P (Mahr GmbH, Gottingen, Germany). ANOVA and Games-Howell post-hoc test were used in statistical analysis. Results: Tested remineralisation agents do not induce statistically significant differences in surface roughness, E and YS in loading or unloading in comparison to control dH2O solution in both wire types. In comparison to as-received wire condition without exposure to any agent exposure to remineralisation agents and dH2O increases E and YS in both types of wires (p<0.05), and increases surface roughness in rhodium coated, but not uncoated wires (p=0.016). MiPaste plus induces more surface roughness than Mirafluor. Influence of MiPaste plus is more pronounced in increase of unload YS in both wire types (p<0.05). Conclusion: It appears that rhodium coating of NiTi wires, in an effort to improve wire aesthetics, results in susceptibility to influences of aquatic media, including enamel remineralisation agents. The wire can become rougher and less elastic which can prolong levelling phase of therapy. MiPaste Plus has stronger influence on tested wires, in comparison to Mirafluor.

rhodium coating; orthodontic wires; elastic behaviour; fluoride

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