Evaluation of degradation in the performance of orthodontic wires after immersing in acidulated phosphate fluoride prophylactic agent: An in vitro study

Abstract

Introduction: Fluoride prophylactic agents, such as acidulated phosphate fluorides (APFs), are being used extensively to prevent demineralization of white spot lesion around orthodontic brackets. However, corrosion has been reported in the acid fluoride solution prophylactic agents altering the mechanical properties of wires. Aim: The aim of the study was to evaluate the degradation in performance of four major orthodontic wires after short-term immersion in APF oral prophylactic agent. Materials and Methods: Four types of orthodontic wires were selected, namely, nickel-titanium wire, beta-titanium wire, stainless steel wire, and cobalt-chromium-nickel wire. These were immersed in a solution of APF-gel or APF-containing mouthwash. Surface changes of treated wires were observed under scanning electron microscope (SEM). The tensile strength of the wires was measured using universal testing machine. The data obtained were noted and subjected for statistical analysis using factorial ANOVA test. Results: SEM showed greater surface corrosion in nickel-titanium and beta-titanium wires and less surface corrosion in stainless steel and cobalt-chromium-nickel wires. Cobalt-chromium-nickel wires showed a higher mean tensile strength followed by stainless steel, beta-titanium, and nickel-titanium wires, respectively, when used with control and mouthwash immersion. With APF-gel, higher mean tensile strength was recorded in stainless steel wires. Conclusions: There was degradation in the performance of orthodontic wires after short-term immersion in the APF prophylactic agent. Greater surface corrosion was observed in nickel-titanium and beta-titanium wires, and less surface corrosion was observed in stainless steel and cobalt-chromium-nickel wires.