title: Effect of acetic NaF solution on the corrosion behavior of stainless steel orthodontic brackets.
abstract: This study assessed the effect of acetic NaF solutions on stainless steel orthodontic brackets. Acetic acid was added to a 0.1% NaF solution to make two solutions, one with pH 3.5 and the other with pH 6. For the two different stainless steel brackets (Tomy, Dentaurum) used in this study, they had a similar elemental composition--except with Mo (molybdenum) in the Tomy bracket. The brackets were then immersed in the prepared test solutions for three days and their responses evaluated. In terms of hydrofluoric acid (HF) concentration, the 0.1%/pH 3.5 solution showed a high HF concentration at 227 ppm, while that of 0.1%/pH 6 solution was very low at 7 ppm. In terms of color change and element release, only the Dentaurum brackets in 0.1%/pH 3.5 solution showed an appreciable color change (deltaE* = 4.0) and released a great amount of elements (Fe, Cr, Ni, Mn) after three days. Otherwise, regardless of pH value and product, only minor color change (deltaE* < 1.0) and negligible element release occurred. In terms of surface modification, no visible changes in surface morphology were observed in any product after immersion in test solutions.
authors.affiliation: Department of Orthodontics, College of Dentistry, Pusan National University, Pusan 602-739, Korea.
authors.forename: Hee-Song
authors.initials: HS
authors.lastname: Jang
authors.forename: Woo-Sung
authors.initials: WS
authors.lastname: Son
authors.forename: Soo-Byung
authors.initials: SB
authors.lastname: Park
authors.forename: Hyung-Il
authors.initials: HI
authors.lastname: Kim
authors.forename: Hoon Kwon
authors.initials: HK
authors.lastname: Yong
mesh_terms: D019342:Acetic Acid; D003116:Color; D003343:Corrosion; D006858:Hydrofluoric Acid / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D016910:Orthodontic Brackets; D012969:Sodium Fluoride / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008670:Metals; D013193:Stainless Steel; D012969:Sodium Fluoride; D019342:Acetic Acid; D006858:Hydrofluoric Acid