Cytotoxicity Comparison of Different Common Bracket-Wires Combinations used in Orthodontic Treatment

Masood Feizbakhsh¹, Razie Mirsafaei^1*, Soosan Sadeghian¹ and Mehrafarin Fesharaki²

¹Department of Orthodontics, School of Dentistry, Islamic Azad University of Isfahan (Khorasgan) Branch, Isfahan, Iran.

²Department of Cell Sciences Research Center, Medical Sciences University of Isfahan, Isfahan, Iran.

Corresponding Author E-mail: Razimir62@yahoo.com

DOI : http://dx.doi.org/10.13005/bbra/2337

ABSTRACT: Since metallic ions are vital for adverse biologic effects such as allergy, cytotoxicity, mutagenicity and carcinogenicity, the corrosion of alloys is the key importance of its biocompatibility. The purpose of this study was comparing the cytotoxicity generated by different combination of common orthodontic bracket and wire after 7, 15 and 30 days. The materials include 5cm of 16 2 inch stainless steel, nickel titanium and beta titanium wires were coupled to central incisor to second premolar stainless steel brackets. To examine cytotoxicity, human gingival fibroblasts directly exposed to different couples. Cell culture was added to the plate of 6 wells containing the specimens and incubated in 5% carbon dioxide at 37°C and cell viability for each pair corrosion products compared by MTT test. One-way ANOVA and RM ANOVA analysis were used and p value <0.05 was considered significant. The analysis showed different range of cytotoxicity between various combinations and days, respectively (P<0.05). Post-hoc pairwise comparison illustrated cytotoxicity decreased with time (P<0.001) and in comparison of different combinations, Beta-Titanium wire with Stainless steel bracket generates the highest cytotoxicity and had significant differences with stainless steel brackets-stainless steel wires (P=0.007) and nickel titanium wire and brackets was in between with insignificant differences (P=0.369 with Beta-Titanium combination and P=0.069 with stainless steel combination). Coupling titanium alloys with stainless steel alloy remarkably increased the corrosion of stainless steel alloy induced localized cytotoxic effects.

KEYWORDS: Archwires; Brackets; Galvanic corrosion; Orthodontic alloy

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