Effect of Topical Fluoride Agents on Orthodontics

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First Posted: 09 Mar 2006 06:39 pm

Abstract from research to be presented at the 2006 ADEA/AADR/CADR Convention in Orlando, Florida, March 6 - 11, 2006

"Effect of Topical Fluoride Agents on Orthodontic Wire Mechanical Properties"

M.P. WALKER1, D. RIES1, K. KULA1, M. ELLIS2, and B. FRICKE3, 1University of Missouri - Kansas City, USA, 2private practice, Burke, VA, USA, 3University of Missouri - Kansas City

Titanium-based and stainless steel alloy orthodontic wires have good biocompatibility and corrosion resistance attributed to a thin stable oxide layer. Nevertheless, fluoride prophylactic agents can cause degradation of the oxide layer resulting in corrosion which may be linked to mechanical property degradation. Objectives: The purpose of this investigation was to study the effect of fluoride prophylactic agents on the mechanical properties of stainless steel and beta-titanium orthodontic archwires. Methods: Rectangular stainless steel and beta-titanium wires (N=15) were immersed in either an acidulated fluoride agent, a neutral fluoride agent, or distilled water (control) for 1.5 hours at 37˚C. After immersion, the loading and unloading elastic modulus and yield strength of the wires were measured with a 3-point bend test in a water bath at 37˚C, in accordance with the criteria in the current American National Standard/American Dental Association Specification No. 32 for Orthodontic Wires (2000). Scanning electron microscopy was also used to characterize the effects of fluoride treatment on the wire topography. Results: Unloading mechanical properties of stainless steel and beta-titanium orthodontic wires were significantly decreased after exposure to both fluoride agents. (1-way ANOVA and Dunnett's post hoc, α = .05) Corrosive changes in surface topography were observed for both beta-titanium and stainless steel wires; however, the surface change was greater with the acidulated fluoride agent as compared to neutral fluoride. Conclusions: The results suggest that topical fluoride agents used in combination with stainless steel or beta-titanium wires could decrease the functional unloading mechanical properties of the wire and contribute to prolonged orthodontic treatment.

SOURCE:
http://iadr.confex.com/iadr/2006Orld/te ... _73009.htm