Korean J Orthod.  2012 Dec;42(6):297-306. 10.4041/kjod.2012.42.6.297.

In vitro physical, chemical, and biological evaluation of commercially available metal orthodontic brackets

• Kim JH
• Cha JY
• Hwang CJ

• KMID: 1976682
• DOI: http://doi.org/10.4041/kjod.2012.42.6.297

Abstract

OBJECTIVE
This in vitro study was undertaken to evaluate the physical, chemical, and biological properties of commercially available metal orthodontic brackets in South Korea, because national standards for these products are lacking.
METHODS
Four bracket brands were tested for dimensional accuracy, (manufacturing errors in angulation and torque), cytotoxicity, composition, elution, and corrosion: Archist (Daeseung Medical), Victory (3M Unitek), Kosaka (Tomy), and Confidence (Shinye Odontology Materials).
RESULTS
The tested rackets showed no significant differences in manufacturing errors in angulation, but Confidence brackets showed a significant difference in manufacturing errors in torque. None of the brackets were cytotoxic to mouse fibroblasts. The metal ion components did not show a regular increasing or decreasing trend of elution over time, but the volume of the total eluted metal ions increased: Archist brackets had the maximal Cr elution and Confidence brackets appeared to have the largest volume of total eluted metal ions because of excessive Ni elution. Confidence brackets showed the lowest corrosion resistance during potentiodynamic polarization.
CONCLUSIONS
The results of this study could potentially be applied in establishing national standards for metal orthodontic brackets and in evaluating commercially available products.

Keyword

Orthodontic brackets; Cytotoxicity; Elution; Corrosion

MeSH Terms

Animals
Corrosion
Fibroblasts
Ions
Mice
Orthodontic Brackets
Republic of Korea
Torque
Ions

Figure

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  Figure 1 Measurement of angulation (α). X, Mesiodistal long axis of the slot; 1, line perpendicular to X; 2, central occlusogingival axis.

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  Figure 2 Measurement of torque. X, Mesiodistal long axis of the slot; 1, plane perpendicular to X in the centre of the slot; 2, line bisecting the slot in the occlusogingival direction; 3, intersection of line 2 and the tooth side surface of the base in plane 1; 4, tangent to the base at 3; 5, line perpendicular to line 4 at 3; θ, angle of torque.

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  Figure 3 Preparation of cells and specimens for the cytotoxicity test.

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  Figure 4 Samples and their respective bases for the corrosion test.

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  Figure 5 Frontal view of the tested brackets. KA, Korea-Archist; AV, America-Victory; JK, Japan-Kosaka; CC, China-Confidence.

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  Figure 6 Cross-sectional view of the tested brackets. KA, Korea-Archist; AV, America-Victory; JK, Japan-Kosaka; CC, China-Confidence.

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  Figure 7 Appearance of cells around the specimens in the cytotoxicity test. KA, Korea-Archist; AV, America-Victory; JK, Japan-Kosaka; CC, China-Confidence.

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  Figure 8 Volume of metal ions released according to elapsed time. KA, Korea-Archist; AV, America-Victory; JK, Japan-Kosaka; CC, China-Confidence.

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