The Effect of Different Methods of Fluoride Administration at Different Concentrations on the Load-Deflection Properties of Rhodium-Coated Niti Archwires

Fluoride compounds are widely used for the control of dental plaque. Considering the effect of different fluoride compounds on the mechanical properties of orthodontic wires, this study was conducted to analyze the effect of different methods of fluoride administration at different concentrations on the load-deflection properties of rhodium-coated NiTi orthodontic archwires.

This clinical trial was conducted on 30 patients aged between 15 and 25 years referring to Babol University of Medical Sciences due to dental crowding and didn't have vertical skeletal defects. 0.016-inch Rhodium-Coated A-NiTi wire was placed on patients' maxillary brackets. Patients were randomly divided into three groups of ten: The control group used only fluoride toothpaste, the second group used fluoride toothpaste with sodium fluoride mouthwash (0.05%) and the third group used fluoride toothpaste with Acidulated Phosphate Fluoride gel (1.23% APF). After six weeks, the values of unloading force (N), yield strength (N/m2) and stiffness (N/m) of the wires were obtained using a three-point bending test.

The mean unloading force and stiffness of the second group wires were higher than that of the other groups and in the first group, they were higher than the control group in all values, but no significant differences were found between the groups. There was a significant difference between the yield strengths of different groups (p=0.038). The mean yield strength in the second group was higher than the other groups (0.94±0.16 N/m2) and was significantly different from the control group (0.75±0.19 N/m2) (p=0.030).

According to this study, method of fluoride administration does not affect the unloading force and stiffness but the yield strength of rhodium-coated NiTi archwires increases with an increase in the fluoride concentration.