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KMID : 0988420020140010062
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Journal of Dental Science (C.N.U.)
2002 Volume.14 No. 1 p.62 ~ p.71
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The Change of Physical Properties of Orthodontic Rectangular Stainless Steel Wire by Electroplating
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Abstract
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The purpose of this study was to evaluate clinical applications of electroplating method through investigation of the physical properties of orthodontic rectangular wires according to varying their cross section. For the study, it was accomplished to electroplate the 0.016-inched orthodontic rectangular stainless steel wire.
The cross section of stainless steel orthodontic rectangular wire increased from 0.016 X 0.016 inch to 0.017 X 0.017 inch by electroplating. The wire was heat treated to improve an adhesion between the wire and electroplated metal.
A three-point bending test and torsion test were conduced in order to compare physical properties among three wire groups; 0.016 X 0.016 wires(group 016P) and 0.017 X 0.017 wires(group 017). Through the investigations of each wire group, following results were obtained.
1. At three-point bending test, the group 016P showed higher tendency in the degree of stiffness, yield strength and ultimate tensile strength than the group 016. Stiffness and ultimate tensile strength showed statistically significant differences between two groups at three-point bending test(p<0.05).
2. Stiffness, yield strength, and ultimate tensile strength of the group 016P showed lower tendency than those of the group 017. Stiffness showed statistically significant differences between two groups at three-point bending test(p<0.05).
3. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 016P showed higher tendency than those of the group 016. All measurements showed statistically significant differences between two groups after torsion test(p<0.05).
4. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 016P showed lower tendency than those of the group 017. Yield torsional moment, and ultimate torsional moment showed statistically significant differences between two groups after torsion test(p<0.05).
Xylitol is a 5-carbons carbohydrate, which can be replaced with sucrose for preventing caries. The replication of Streptococcus mutans and its formation of artificial plaque were studied in the media containing xylitol. The combined effect of xylitol and other carbohydrates on Streptococcus mutans was also studied.
The replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol. Streptococcus mutans replicated at the initial stage of incubation in the media contaning glucose, fructose or lactose, while replication from the beginning of incubation in the media containing fructose as combining with xylitol. The formation of artificial plaque by Streptococcus mutans was significantly reduced in the media containing with xylitol and fructose.
These results indicated that the replication of Streptococcus mutans was inhibited according to the increased concentration of xylitol, and the formation of artificial plaque by Streptococcus mutans was significantly inhibited in the media containing xylitol and fructose.
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