• Journal of Animal Science and Technology
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• v.50 no.6
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• pp.857-864
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• 2008

This study was conducted to identify various habits of stable vices and its occurring frequency in racing horses, currently managed in Korea, through categorizing the total 1,386 head of racing horses in Seoul Racing Park into sex, age and years of stabling. Among the 1,386 horses, 524 heads(37.8%) have shown habits of stable vices and its appearances rate according to each category is as following; While 40.7% of stallions showed the highest appearances rate of stable vices by sex, it was 50%, 44.2%, and 53% for the age of 2, 6 and 4, respectively by age, it was 41%, 40.6% and 39.1% for the years of stabling of 2, 4 and 3, respectively. For the appearances rate of individual stable vices, 7.0% of mares showed the highest appearances rate of ‘kicking at walls’, 12.9% of stallions showed ‘biting habit’ and 5.7% of castrated horses showed ‘weaving’ when grouped by sex. According to age, 8.3%, and 6.1% of horses of age 2 showed ‘kicking at walls’, ‘wind-sucking’ and ‘pawing’, respectively while 4.9% of horses of age 3 showed ‘pawing’, 6.4% of horses of age 4 showed ‘kicking at walls’, 6.8% of horses of age 5 showed ‘kicking at walls’ and ‘biting habit’ and 8.7% of horses of age 6 showed ‘weaving’ and ‘biting habit’. By the year of stabling, 6% of horses for 1 year had ‘pawing habit’, 7% og horses for 2 years had ‘kicking at walls’, 7.4% of horses for 3 years had ‘biting habit’ and it was 6.9% and 10.6% for ‘weaving’ for 4 and 5 years of stabling, respectively. In conclusion, the racing horses in Korea seemed to show high rate of appearance rate of stable vices and it is considered to be necessary to improve stable equipments and management skills to reduce the appearance rate of stable vices.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.345-351
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• 2015

Purpose: The purpose of this study was to evaluate the proper axial thickness of zirconia abutment applied to implant in the anterior region. Materials and methods: Zirconia abutments were prepared at different axial wall thickness by processing pre-sintered zirconia blocks via CAD/CAM to obtain equal specimens. The abutments were each produced with a thickness of 0.5 mm (Group 1), 0.8 mm (Group 2), 1.2 mm (Group 3), or 1.5 mm (Group 4). The implant used in this study was a external connection type one (US, Osstem, Pussan, Korea) product and the zirconia abutment was prepared via replication of a cemented abutment. The crowns were prepared via CAM/CAM with a thickness of 1.5 mm and were cemented to the abutments using $RelyX^{TM}$ UniCem cement. A universal testing machine was used to apply load at 30 degrees and measure fracture strength of the zirconia abutment. Results: Fracture strength of the abutments for Group 1, Group 2, Group 3, and Group 4 were $236.00{\pm}67.55N$, $599.00{\pm}15.80N$, $588.20{\pm}33.18N$, and $97.83{\pm}98.13N$, respectively. Group 1 showed a significantly lower value, as compared to the other groups (independent Mann-Whitney U-test. P<.05). No significant differences were detected among Group 2, Group 3, and Group 4 (independent Mann-Whitney U-test. P>.05). Conclusion: Zirconia abutment requires optimal thickness for fracture resistance. Within the limitation of this study, > 0.8 mm thickness is recommended for zirconia abutment in anterior implants.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.693-698
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• 2006

In Class I cavity, the highest C-factor could be obtained and it means the highest polymerization shrinkage stress. In this study, high C-factor model was designed. The pulpose of present study was to determine differences of Microtensile bond strength (MTBS) of class I cavity pulpal and axial wall specimens in primary molar. Twenty clean mandibular 2nd primary molars were randomly divided into two groups Different composite Resins (Filtek Z250, 3M ESPE & Filtek Supreme, 3M ESPE) were bulk filled and photo cured. Axial wall specimens and pulpal specimens were prepared at the same teeth, All specimens were divided into 4 groups and MTBS were evaluated. Group ZP : Filtek Z250-Pulpal wall Group ZA : Filtek Z250-Axial wall Group SP : Filtek Supreme - Pulpal wall Group SA : Filtek Supreme - Axial wall The results were as follows: 1. Mean MTBS of ZP & ZA and SP & SA were significantly different(p<.001). 2. There was no significant difference between MTBS of ZP & SP and ZA & SA.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.368-374
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• 2012

Dental CAD (computer-aided design)/CAM (computer-aided manufacturing) systems facilitate the use of zirconia core for all-ceramic crown. The purpose of this study was to evaluate the marginal and internal fit of zirconia core fabricated using a dental CAD/CAM system and to compare the fit of metal cores by a conventional method. Ten identical cases of single coping study models (abutment of teeth 11) were manufactured and scanned. Ten zirconia cores were fabricated using dental CAD/CAM system. An experienced dental technician fabricated 10 samples of metal cores for the control group using the lost wax technique. Marginal and internal fit was measured by the silicone replica technique. Fit was measured with magnification of 160 using a digital Microscope. Margin, rounded chamfer, axial wall and incisal fits were measured for comparison. T-test of independent sample for statistical analysis was executed with SPSS 12.0 for Windows (SPSS Inc., Chicago, IL, USA) (${\alpha}$=0.05). The mean (SD) for marginal, rounded chamfer, axial wall and incisal were: $97.0\;(25.3){\mu}m$, $104.0\;(22.0){\mu}m$, $59.6\;(21.4){\mu}m$ and $124.8\;(33.3){\mu}m$ for the zirconia core group, and $785.2\;(18.4){\mu}m$, $83.8\;(15.1){\mu}m$, $42.7\;(9.6){\mu}m$ and $83.4\;(14.4){\mu}m$ for the metal core group. T-test showed significant differences between groups for margin (p<.001), rounded chamfer (p<.001), axial wall (p<.001) and incisal (p<.001). But zirconia core group observed that the marginal and internal fit values in the present study were within clinically acceptable range.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.236-244
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• 2011

Purpose: This study was aimed to compare the margin and internal fitness of 3-unit zirconia bridge cores fabricated by several CAD/CAM systems using replica technique. Materials and methods: Three unit-bridge models in which upper canine and upper second premolar were used as abutments and upper first premolar was missed, were fabricated. Fourty models were classified into 4 groups (Cerasys$^{(R)}$ (Group C), Dentaim$^{(R)}$ (Group D), KaVo Everest$^{(R)}$ (Group K), $Lava^{TM}$ (Group L)), and zirconia cores were fabricated by each company. Sixteen points were measured on each abutment by replica technique. Statistical analysis was accomplished with two way ANOVA and Dunnett T3 (${\alpha}$=.05). Results: In most systems, there was a larger gap on inter margin than outer margin. In the Group K, overall fitness was excellent, but the incisal gap was very large. In the Group C, marginal gap was significantly larger than Group K, but overall internal gap was uniform (P<.05). The axial gap was under $100\;{\mu}m$ in all system. The difference between internal and external gap was small on Group L and C. However, internal gap was significantly larger than external gap in Group D (P<.05). The fitness of canine was better than second premolar among abutments (P<.05). Conclusion: The marginal and internal gap was within the clinically allowed range in all of the three systems. There was a larger gap on second premolar than canine on internal and marginal surface. In most systems, there was a larger gap on occlusal surface than axial surface.