engleski

Working properties of nickel-titaniuma archwires after corrosion in oral antiseptics and saliva

AIMS: To explore working properties of uncoated, rhodium- and nitride-coated nickel-titanium wires after corrosion in artificial saliva and various oral antiseptic solutions. MATERIALS AND METHOD: Uncoated (uNiTi), rhodium- (RhNiTi) and nitride- (NNiTi) coated nickel- titanium wires were immersed in artificial saliva for 28 days and incubated at 37°C. Every week the wires were taken out of the artificial saliva and immersed in Gengigel, Curasept and Listerine for 5 minutes at 37°C. For the negative control, one set of wires was immersed in artificial saliva alone. For absolute control, one set of wires was tested in as-received condition. There were six specimens for every wire/experimental condition. Three-point-bending was performed on 2.5 cm long wire samples upon completion of immersion protocol. The load-deflection curves were used to obtain data on total energy (during loading), recovered energy (during unloading) and dissipated energy (difference between loading and unloading energy). One-way ANOVA with Student- Newman-Keuls post hoc test and Pearson’s correlations were used for analysis. RESULTS: For the uNiTi wire there were no differences between the observed media during unloading. Curasept induced significantly higher total energy, when compared to both negative and absolute controls (p=0.004). Dissipated energy was significantly higher after exposure to Curasept and Gengigel, as compared to the as- received and artificial saliva alone samples (p=0.002). There was significant difference between media for total, recovered and dissipated energy for both RhNiTi wire (p≤0.004), and NNiTi wire (p≤0.002). The lowest level of recovered energy was for NNiTi after exposure to Listerine. Pearson’s correlation showed that the fluoride ion concentration in oral antiseptics was best predictor of energy levels in uNiTi and RhNiTi, in direct proportion to the increase in total, recovered and dissipated energy for the uNiTi (r=0.653, p<0.001 ; r=0.447, p=0.013 ; r=0.523, p= 0.003), and for the RhNiTi (r=0.783, p<0.001 ; r=0.443, p=0.014 ; r=0.539, p=0.002). For NNiTi, the concentration of hydrofluoric acid is a better predictor than fluoride ions. CONCLUSION: The recovered energy of NiTi archwires, which are used to move teeth, deteriorates only in NNiTi wire due to corrosion in Listerine.

corrosion ; nickel ; titanium ; antiseptics ; elasticity

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