• Korean Architects
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• s.591
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• pp.62-63
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• 2018

• Korean Architects
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• s.607
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• pp.32-53
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• 2019

• The Journal of Advanced Prosthodontics
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• v.10 no.3
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• pp.211-217
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• 2018

PURPOSE. To evaluate the effect of prolonged sandblasting on the bond durability of dual-cure adhesive resin cement to computer-aided design and computer-aided manufacturing (CAD/CAM) restoratives. MATERIALS AND METHODS. Nano-ceramic LAVA Ultimate and hybrid-ceramic VITA Enamic CAD/CAM blocks were used for this study. Each CAD/CAM block was sectioned into slabs of 4-mm thickness for the microtensile test (${\mu}TBS$) test and 2-mm thickness for the surface roughness test. Three groups were created according to the sandblasting protocols; group 1: specimens were sandblasted for 15 seconds, group 2: specimens were sandblasted for 30 seconds, and group 3: specimens were sandblasted for 60 seconds. After sandblasting, all specimens were luted using RelyX Ultimate Clicker. Half the specimens were subjected to ${\mu}TBS$ tests at 24 hours, and the other half were subjected to tests after 5000 thermocycles. Additionally, a total of 96 CAD/CAM block sections were prepared for surface roughness tests and scanning electron microscopy (SEM) evaluations. The Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance, and Dunn's post hoc test were used to compare continuous variables among the groups. RESULTS. At baseline, group 1, group 2, and group 3 exhibited statistically similar ${\mu}TBS$ results for LAVA. However, group 3 had significantly lower ${\mu}TBS$ values than groups 1 and 2 for VITA. After 5000 thermocycles, ${\mu}TBS$ values significantly decreased for each block (P<.05). CONCLUSION. It is important to perform controlled sandblasting because it may affect bond strength results. Sixty seconds of sandblasting disturbs the initial ${\mu}TBS$ values and the stability of adhesion of CAD/CAM restoratives to dual-cure adhesive resin cement for VITA Enamic.

• The korean journal of orthodontics
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• v.48 no.2
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• pp.107-112
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• 2018

Objective: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. Methods: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. Results: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. Conclusions: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.101-112
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• 2018

PURPOSE. The purpose of this study was to investigate the effect of various surface treatments (ST) on the shear bond strength of resin composite to three bilayer dental ceramics made by CAD/CAM and two veneering ceramics. MATERIALS AND METHODS. Three different bilayer dental ceramics and two different veneering ceramics were used (Group A: IPS e.max CAD+IPS e.max Ceram; Group B: IPS e.max ZirCAD+IPS e.max Ceram, Group C: Vita Suprinity+Vita VM11; Group D: IPS e.max Ceram; Group E: Vita VM11). All groups were divided into eight subgroups according to the ST. Then, all test specimens were repaired with a nano hybrid resin composite. Half of the test specimens were subjected to thermocycling procedure and the other half was stored in distilled water at $37^{\circ}C$. Shear bond strength tests for all test specimens were carried out with a universal testing machine. RESULTS. There were statistically significant differences among the tested surface treatments within the all tested fracture types (P<.005). HF etching showed higher bond strength values in Groups A, C, D, and E than the other tested ST. However, bonding durability of all the surface-treated groups were similar after thermocycling (P>.00125). CONCLUSION. This study revealed that HF etching for glass ceramics and sandblasting for zirconia ceramics were adequate for repair of all ceramic restorations. The effect of ceramic type exposed on the fracture area was not significant on the repair bond strength of resin composites to different ceramic types.

• Journal of Veterinary Clinics
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• v.11 no.1
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• pp.347-358
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• 1994

This study was peformed to investigate the morbidity of nutritional secondary hyperparathyroidism(NSH) caused by imbalance of Ca and p, and related athletic disease in Cheju pony racehorse. The seventeen horses with clinical signs among 33 NSH affected, administered CaCO$_3$(34 g) and Vita-rinka1(120 g) respectively for 40 days. The results were asd follows; Morbidity of NSR was 33 among 47 horses, and it was caused by the deficiency of Ca in 32 horses. In a case, level of Ca was norm질 although P was high. There was no case of Ca deficiency with P excess. Among 33 NSH affected horses, 13 were subclinical and 20 were clinical types with severe lameness in 6 and transient lameness in 14. Although there was no difference in bone density between transient lameness and normal horses on radiography, among six horses wlth severe lameness two showed hyperplasia at periosteum, one had low density of phalanges and metacarpal bones, and thin cortex. and there with fracture at carpus, nivicular bone and proximal sesamoids. The levels of FECa and FEP were recovered after CaCO$_3$ administration in 2 horses among ten, and after Vita-rinkal in all of seven. The clinical signs were disappeared in slx horses among ten CaCO$_3$ treated, and in five among seven Vita-rinkal treated. There were no differences on radiography in bone density and thickness of cortex on 14 horses with transient lameness. Three horses with severe signs were recovered to normal bone density and thickness of cortex, and there was no significant difference between two groups. In summary, the morbidity of NSH in Cheju pony racehorses was relatively high because of deficiency of Ca. Constant admistration of Ca supplements is desirable to treat and prevent athletic disease development in Cheju racehorses.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.965-973
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• 2008

In this study, we compared the quality and sensory characteristics of 4 types of fresh tomatoes and 2 types of canned tomatoes, and then determined the most preferred quality characteristics and tomato type for the production of tomato sauce. The sample tomatoes were prepared by cutting after either peeling or heating for 5 min. Soluble solids were in the following order: Italian canned >American canned, Cherry> Vita king > Aranka > general tomatoes. The primary free sugars were fructose and glucose, and we determined that fructose and glucose were the most prevalent sugars in the cherry and American canned tomatoes. The total sugars, which were the sum of the fructose and glucose contents, were consistent with the soluble solid contents. pH was measured in the following order: general> Italian canned> Cherry, Vitaking> Aranka> American canned tomatoes. The most abundant amino acid was glutamic acid, and its content in the unheated tomatoes occurred in the following order: American canned> Italian canned> Vita king> Cherry> general tomatoes; however, after heating, the Vita king tomato was followed by the American canned tomato. The lightness (L value) of the fresh tomatoes tended to be higher than that of the canned tomatoes, and it decreased after heating. The redness (a value) of the unheated tomatoes was in the following order: Italian canned> American canned> Vitaking tomatoes; after heating, the Vitaking evidenced the highest values, followed by the canned tomatoes. The result of our QDA profile of sensory characteristics according to redness, aroma, sweet taste, sour taste, palatability, and viscosity was in the following order: Italian canned > American canned > Vitaking tomatoes, which evidenced the most balanced hexagonal shape. In the preference test, 2 types of canned tomatoes and Vitaking tomatoes were the most preferred among the fresh tomatoes. From the correlation coefficients among the sensory characteristics, canned tomatoes were the most preferred for the production of tomato sauce due to its high redness, flavor, palatability, and viscosity values. Vitaking tomatoes were the most appropriate among the fresh tomatoes.

• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.60.1-60.8
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• 2021

Objectives: The aim of this study was to verify the match between 5 shades of composites from different manufacturers with a shade guide and among the systems using a portable spectrophotometer. Materials and Methods: Shade measurements were performed on specimens of Z350 XT (3M ESPE), Charisma Diamond (Heraeus Kulzer GmbH), Esthet X-HD (Dentsply Caulk), and Empress Direct (Ivoclar-Vivadent) for shades A1, A2, A3, B1, and C3 using a Vita Easyshade spectrophotometer (Vita Zahnfabrik) against a white background. Corresponding shades of Vitapan Classical (Vita Zahnfabrik) guide were measured likewise and shade variation (ΔE) was calculated based on International Commission on Illumination L^*a^*b^* parameters. The ΔE of the composites in each shade was compared by one-way analysis of variance and Tukey's post hoc test (α = 0.05). Results: All composites presented ΔE > 3.7 compared with the shade guide. Variation in shades A3, B1, and C3 was significantly different for all composites. ΔE of Z350 XT was significantly lower for A1 than for the other shades, whereas ΔE of Z350 XT and Charisma Diamond were significantly lower for A2 than for the other shades. Conclusions: No composite shade matched with the shade guide. Equivalent shades of the restorative composite from different manufacturers may show clinically noticeable ΔE.

• The korean journal of orthodontics
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• v.54 no.3
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• pp.160-170
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• 2024

Objective: Owing to the availability of 3D software, scanners, and printers, clinicians are encouraged to produce in-office aligners. Recently, a new direct-printing resin (Tera Harz TC-85DAC) has been introduced. Studies on its mechanical characteristics and biological effects have been published; however, evidence on its efficacy in orthodontic treatment remains scarce. This pilot study aimed to investigate the accuracy of teeth movement achieved with direct-printed aligners. Methods: Seventeen patients (eight males and nine females) with a mean age of 27.67 ± 8.95 years, presenting with dental rotations < 30° and spaces/crowding < 5 mm, were recruited for this study. The teeth movement was planned starting from a T0 digital dental cast. The 3D direct-printed aligners were produced using Tera Harz TC-85DAC resin. Once the orthodontic treatment was completed, a final digital cast was obtained (T1). The planned teeth positions were then superimposed onto the T0 and T1 digital models. The differences between the programmed movements and the achieved overall torque, tip, rotation, and transverse dimensions were assessed using the paired t test or Wilcoxon's signed rank test. Results: The overall accuracies for torque, tip, and rotation were 67.6%, 64.2%, and 72.0%, respectively. The accuracy of the change in transverse diameter was 99.6%. Conclusions: Within the limits of the present pilot study (difficulties with abnormally shaped teeth and use of attachments), it can be concluded that 3D printed aligners can be successfully printed in-house and utilized for mildly crowded cases, with a comparable accuracy of tooth movement to that of other aligners.

• The Journal of Advanced Prosthodontics
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• v.1 no.3
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• pp.113-117
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• 2009

STATEMENT OF PROBLEM. Recently Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) has been introduced due to superior flexural strength and fracture toughness compared to other dental ceramic systems. Although zirconia has outstanding mechanical properties, the phenomenon of decrease in the life-time of zirconia resulted from degradation in flexural strength after low temperature aging has been reported. PURPOSE. The objective of this study was to investigate degradation of flexural strength of Y-TZP ceramics after various low temperature aging treatments and to evaluate the phase stability and micro-structural change after aging by using X-ray diffraction analysis and a scanning electron microscope (SEM). MATERIAL AND METHODS. Y-TZP blocks of Vita In-Ceram YZ (Vita Zahnfabrik, Bad $S\ddot{a}ckingen$, Germany) were prepared in 40 mm (length) $\times$ 4 mm (width) $\times$ 3 mm (height) samples. Specimens were artificially aged in distilled water by heat-treatment at a temperature of 75, 100, 125, 150, 175, 200, and $225^{\circ}C$ for 10 hours, in order to induce the phase transformation at the surface. To measure the mechanical property, the specimens were subjected to a four-point bending test using a universal testing machine (Instron model 3365; Instron, Canton, Mass, USA). In addition, X-ray diffraction analysis (DMAX 2500; Rigaku, Tokyo, Japan) and SEM (Hitachi s4700; Jeol Ltd, Tokyo, Japan) were performed to estimate the phase transformation. The statistical analysis was done using SAS 9.1.3 (SAS institute, USA). The flexural strength data of the experimental groups were analyzed by one-way analysis of variance and to detect statistically significant differences ($\alpha$= .05). RESULTS. The mean flexural strength of sintered Vita In-Ceram YZ without autoclaving was 798 MPa. When applied aging temperature at below $125^{\circ}C$ for 10 hours, the flexural strength of Vita In-Ceram YZ increased up to 1,161 MPa. However, at above $150^{\circ}C$, the flexural strength started to decrease. Although low temperature aging caused the tetragonal-to-monoclinic phase transformation related to temperature, the minimum flexural strength was above 700 MPa. CONCLUSION. The monoclinic phase started to appear after aging treatment above $100^{\circ}C$. With the higher aging temperature, the fraction of monoclinic phase increased. The ratio of monoclinic/tetragonal + monoclinic phase reached a plateau value, circa 75% above $175^{\circ}C$. The point of monoclinic concentration at which the flexural strength begins to decrease was between 12% and 54%.