Effect of Saliva on Load-Deflection Characteristics of Superelastic Nickel-Titanium Orthodontic Wires

Most published results about the characteristics of NiTi wires are based on the mechanical laboratory tests on the as-received wires.The purpose of this study was to investigate the effect of saliva on load-deflection characteristics of superelastic NiTi wires. In this experimental study, 15 wires of three kinds of superelastic NiTi wires (Sentalloy, Force I and Truflex) were prepared. Five spe-cimens of each wire were tested in the as-received condition (T0) to provide base-line information and the remaining wires were divided into two groups of five. Half of them were kept inside artificial saliva for one month (T1), while the oth-ers were kept in air (T2). After 30 days, three-point bending test was done in a dental arch model and data from selected points on the unloading phase of the generated graphs were used for statistical analysis. Force I and Truflex showed significantly greater force than Sentalloy. The load values of Truflex and Force I after one month exposed to artificial saliva (T1) decreased significantly, but Sentalloy was not affected significantly. The pla-teau gap values were not considerably different among T0, T1 and T2. Saliva decreased the load of Force I and Truflex significantly, but it did not have a statistically significant effect on Sentalloy.