• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.594-603
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• 2020

The aim of this study was to investigate the issue in obese children with a high probability of leading to precocious puberty for they have more advanced skeletal maturation compared to normal children in order to contribute to the health of obese children by identifying the relationship between physique and physical fitness according to their skeletal maturation. A total of 243 obese children between the ages of 10-13 were enrolled as subjects, and the skeletal maturation, which symbolize indicators of biological maturation, were evaluated by using the TW3 method after hand-wrist radiographs, thus classified the skeletal maturation level into retarded group(n=70), normal group(n=128), and advanced group(n=45). A stadiometer and InBody 270 (Biospace, Korea) were used to measure 3 components in physique. A total of 7 components in physical fitness, which included muscular strength, muscular endurance, flexibility, power, cardiovascular endurance, balance, agility, were measured as well. Descriptive statistics and one-way variable analysis (ANOVA) were conducted for data processing using SPSS 25.0, and Duncan's multiple-range method was used for post hoc analysis; and it was considered significant at the level of P< .05. Analysis results of this study may be summarized as follow. First, height and weight in physique factors according to the skeletal maturation between the retarded, normal, and advanced groups in males and females were highly significant. Second, physical fitness comparison according to the skeletal maturation in males were statistically significant in muscular strength, power, and agility whereas muscular strength and balance were statistically significant in females.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.385-396
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• 2007

The aims of this study were to compare the shaping effect and safety between single length technique recommended by manufacturer and crown-down technique using Mtwo rotary file and to present a modified method in use of Mtwo file. Sixty simulated root canal resin blocks were used. The canals were divided into three groups according to instrument and the manner of using methods. Each group had 20 specimens. Group MT was instrumented with single length technique of Mtwo, group MC was instrumented with crown-down technique of Mtwo and group PT was instrumented with crown-down technique of ProTaper. All of the rotary files used in this study were operated by an electric motor. The scanned canal images of before and after preparation were superimposed. These superimposed images were evaluated at apical 1 to 8 mm levels Angle changes were calculated. The preparation time, weight loss, instrument failure and binding, canal aberrations, and centering ratio were measured. Statistical analysis of the three experimental groups was performed with ANOVA and Duncan's multiple range tests for post-hoc comparison and Fisher's exact test was done for the frequency comparison. In total preparation time, group MT and group MC were less than group PT. In the aberrations, group MT had more elbows than those of group MC and group PT. The binding of group MC was least and group MT was less than group PT (P < 0.05). Under the condition of this study, crown-down technique using Mtwo rotary file is better and safer method than single length technique recommended by the manufacturer.