• 대한치과보철학회지
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• 제38권4호
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• pp.510-525
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• 2000

The effects of pretreatment of Co-Cr alloy, including two adhesive primers that contain either MDP or MAC-10, and silicoating on the bond The result sobtained as follows; o Strength of 4-META/MMA-TBB resin were investigated using FT-IR, SEM, and EDAX. o In the SEM observation of surface morphologies, the sandblasted specimen exibited a very rough surface, whereas the surfaces of the two groups primed with either MDP or MAC-10 were covered with a layer of primer, and the surface morphology of the silicoated specimen remained almost the same after sandblasting. o Before the thermocycling tests, the group treated with MDP demonstrated the highest mean tensile bond strength and the sandblasted group showed the lowest bond strength. o After 20,000 thermocyling, the mean tensile bond strength of the sandblasted group exhibited a 50% reduction in bond strength, while the others showed a $20\sim30%$ reduction. o Observation of the metal-resin interface revealed that in all groups the resin permeated the rough surface formed by sandblasting thereby producing a mechanical bond between the metal and the resin. It was also found that thermocycling resulted in a gap formation at the metal-resin interface of the specimens, and the sandblasted group exhibited a larger gap width than the other groups. o In fracture mode, all specimens indicated a cohesive fracture within the resin before thermocycling. However, thermocyling produced adhesive failure at the edge of the resin-metal interface in most specimens. The sandblasted group, which exhibited the lowest bond strength after thormocycling, also demonstrated the largest area of adhesive failure.

• 치과방사선
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• 제26권2호
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• pp.133-145
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• 1996

Aspirating or swallowing foreign bodies is a common occurrence. If they are wholly or partly radiopaque, their localization in and progress through the gastrointestinal tract can be more effective. Of the dental origin foreign materials swallowed, the most common things are fragments of anterior maxillary partial denture. But the radiopacity of denture base resins is not sufficient to determine the location of the objects. The purpose of this study was to develop a radiopaque dental acrylic resin, which has clinically detectible radiopacity with minimal change of mechanical properties and color. The radiopacity, color change(CIE 6..E) and microhardness of acrylic resins were determined after mixing barium sulfate or iodide compound. Thermocycling course was conducted to determine the change of characteristic of resins after using for a long time in the mouth. Five or ten percent of barium sulfate to total weight of cured material was mixed with heat curing dental acrylic resin or chemically curing orthodontic resin. In the case of iodide compound, the mixing ratio was two or three percent. After mixing the high radiopaque materials, resin was cured to 20×20×2 mm plate, polished with #600 sand paper and finally polished with Microcloth(Buehler). The specimens were thermocycled in 5 and 55 t distilled water for 2,000 times, and the measurement of radiopacity, color and Vickers hardness was repeated every 500 times thcrmocycling. The radiopacity of specimens on the X -ray films was measured with densitometer(X-rite). The color change was detennined with differential colorimeter(Model TC-6FX, Tokyo Denshoku), and the Vickers hardness number was measured with microhardness tester(Mitsuzawa). The following results were obtained : 1. All the three variables, the kinds of acrylic resins, the mixing or the kinds of high radiopaque materials and thermocycling, had combined effect on the radiopacity of the dental acrylic resins(p<0.0l). 2. The two variables, the mixing or the kinds of high radiopaque materials and thermocycling, influenced on the radiopacity of the dental acrylic resins(p<0.01). But the kinds of acrylic resins did not influence on the color change of mixed dental acrylic resins(p>0.05). 3. Each of the three variables, the kinds of acrylic resins, the mixing or the kinds of high radiopaque materials and thermocycling, influenced on the radiopacity of dental acrylic resins(p<0.0l). 4. The high radiopaque materials used in this study did not yield clinically usable radiopacity, and the color change was great after mixing those materials.

• 대한치과교정학회지
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• 제39권4호
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• pp.225-233
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• 2009

본 연구는 도재 수복물에 부착된 단결정 세라믹 브라켓의 전단접착강도와 파절양상에 열순환과 도재 수복물의 종류가 어떤 영향을 미치는지 알아보기 위해 시행되었다. 도재전장관에 사용되는 재료들 중 Ceramco 3, Empress II, Zi-ceram/Vintage ZR 세 가지를 선택하여 각 20개씩 총 60개의 시편을 원반형태(두께 2 mm, 직경 12 mm)로 제작하였다. 동일한 접착 술식으로 세라믹 브라켓을 부착한 후 열순환을 시행한 실험군과 시행하지 않은 대조군, 두 군으로 나누어 전단접착강도와 파절양상을 평가하였다. 열순환을 하지 않은 대조군의 전단접착강도는 Ceramco 3는 $7.06\;{\pm}\;1.76\;MPa$, Empress II는 $7.55\;{\pm}\;2.38\;MPa$ 그리고 Zi-ceram/Vintage ZR은 $7.19\;{\pm}\;1.38\;MPa$로 추천되는 전단접착 강도(6 - 8 MPa)에 적합한 강도를 보였으나 열순환을 시행한 실험군은 전단접착강도가 유의하게 감소하였으며(p < 0.05) 열순환 후의 전단접착강도는 Ceramco 3는 $4.88\;{\pm}\;1.00\;MPa$, Empress II는 $5.46\;{\pm}\;1.35\;MPa$ 그리고 Zi-ceram/Vintage ZR은 $4.84\;{\pm}\;1.01\;MPa$로 임상적으로 추천되는 것보다 다소 낮은 값을 보였다. 도재의 종류에 따른 전단접착강도에는 유의한 차이가 없었다. 파절양상은 대조군에서는 모두 브라켓 기저부와 접착제 사이에서 파절이 일어났으며, 실험군에서는 2개의 시편(Ceramco 3과 Zi-ceram/Vintage ZR군에서 각 1개)만이 접착제내 파절을 보였으며 28개의 시편은 브라켓 기저부와 접착제 사이에서 파절이 일어났다. 이상의 연구 결과에서 보았을 때 도재 수복물의 종류에 따른 차이는 없었으나 열순환에 의해 전단접착강도가 약화되므로 실제 임상에서 고려되어야 할 것이다.

• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.128-137
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• 2019

PURPOSE. The aim of this study was to compare the effect of different finishing and polishing techniques on water absorption, water solubility, and microhardness of ceramic or glass-polymer based computer-aided design and computer-aided manufacturing (CAD/CAM) materials following thermocycling. MATERIALS AND METHODS. 150 disc-shaped specimens were prepared from three different hybrid materials and divided into five subgroups according to the applied surface polishing techniques. All specimens were subjected up to #4000 grit SiC paper grinding. No additional polishing has been done to the control group (Group I). Other polishing procedures were as follows: Group II: two-stage diamond impregnated polishing discs; Group III: yellow colored rubber based silicone discs; Group IV: diamond polishing paste; and Group V: Aluminum oxide polishing discs. Subsequently, 5000-cycles of thermocycling were applied. The analyses were conducted after 24 hours, 7 days, and 30 days of water immersion. Water absorption and water solubility results were analyzed by two-way ANOVA and Tukey post-hoc tests. Besides, microhardness data were compared by Kruskal-Wallis and MannWhitney U tests (P<.05). RESULTS. Surface polishing procedures had significant effects on water absorption and solubility and surface microhardness of resin ceramics (P<.05). Group IV exhibited the lowest water absorption and the highest microhardness values (P<.05). Immersion periods had no effect on the microhardness of hybrid ceramic materials (P>.05). CONCLUSION. Surface finishing and polishing procedures might negatively affect physical properties of hybrid ceramic materials. Nevertheless, immersion periods do not affect the microhardness of the materials. Final polishing by using diamond polishing paste can be recommended for all CAD/CAM materials.

• Restorative Dentistry and Endodontics
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• 제32권4호
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• pp.377-384
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• 2007

작금의 치질 접착시스템은 도말층 처리 방법에 따라 전부식형과 자가부식형 접착시스템으로 대별된다. 이러한 두 가지 접착시스템의 효용성을 비교, 평가하고 열순환 횟수에 따른 미세누출도 변화를 측정하기 위해 각각의 접착시스템으로 수복된 우치 5급 수복물에, 수복 초기의 효용성를 의미하는 500회의 열순환 자극과 상대적으로 긴 내구성을 의미하는 5,000회의 열순환 자극을 부여한 다음, 전기화학적 방법으로 측정하였다. 건전한 40개의 단근관을 가진 우치를 이용하여 백악법랑 경계부를 중심으로 5급 와동을 형성하였으며, 치아를 각각 10개씩 4개의 실험군 (열순환 횟수 2종 $\times$ 복합레진 수복 2개 군)으로 분류하였다. 20개의 치아에는 전부식형 접착시스템인 Single bond와 Z250 (shade A4)을, 나머지 20개의 치아에는 자가부식형 접착시스템인 AQ bond와 Metafil (shade A4)로 각각 충전하고 광중합기 (XL2500, 3M ESPE, St. Paul, MN, USA)를 이용하여 $600\;mW/cm^2$의 광도로 40초간 광중합하였다. 모든 시편을 실온에서 24 시간동안 증류수에 보관한 다음, 연마하고 각 수복물의 반은 섭씨 5도와 55도의 수조에 30초씩 담궜으며 이동 시간 10초의 열순환 (thermocycling)을 500회 시행하였고, 나머지 반은 5,000회 실시하였다. 미세 전류 측정을 위해 직류 공급원인 TOE 8841 (TOELLNER electronic instrument GMBH, Germany)을 이용하여 10 V의 전압을 부여하였으며 6514 system Electrometer (Keithley Co., Cleveland, Ohio, USA)로 미세전류 (${\mu}A$)를 측정하였다. 전류를 흐르게 한 다음 5-10분까지 20초 간격으로 측정 한 15개 측정치의 평균값을 시편의 미세전류 측정치로 인정하였다. 각 군간의 미세전류 측정치에 대한 유의성은 수복방법 및 열순환 횟수의 변수에 대한 Two-way ANOVA test로 95% 유의 수준에서 검증하여 다음과 같은 결과를 얻었다. 수복방법과 열순환 횟수 사이의 상호작용은 없었으며 (p = 0.485), 열순환 횟수에 따른 미세누출의 차이도 없었다(p = 0.814). 그러나 자가부식형 접착시스템인 AQ Bond와 Metafil로 수복된 실험군이 전부식형 접착시스템인 Single Bond와 Z250으로 수복된 군에 비해 적은 미세누출도를 보였다 (p = 0.005).

• Restorative Dentistry and Endodontics
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• 제42권3호
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• pp.206-215
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• 2017

Objectives: To determine the combined effect of fatigue cyclic loading and thermocycling (CLTC) on the shear bond strength (SBS) of a resin cement to zirconia surfaces that were previously air-abraded with aluminum oxide ($Al_2O_3$) particles at different pressures. Materials and Methods: Seventy-two cuboid zirconia specimens were prepared and randomly assigned to 3 groups according to the air-abrasion pressures (1, 2, and 2.8 bar), and each group was further divided into 2 groups depending on aging parameters (n = 12). Panavia F 2.0 was placed on pre-conditioned zirconia surfaces, and SBS testing was performed either after 24 hours or 10,000 fatigue cycles (cyclic loading) and 5,000 thermocycles. Non-contact profilometry was used to measure surface roughness. Failure modes were evaluated under optical and scanning electron microscopy. The data were analyzed using 2-way analysis of variance and ${\chi}^2$ tests (${\alpha}=0.05$). Results: The 2.8 bar group showed significantly higher surface roughness compared to the 1 bar group (p < 0.05). The interaction between pressure and time/cycling was not significant on SBS, and pressure did not have a significant effect either. SBS was significantly higher (p = 0.006) for 24 hours storage compared to CLTC. The 2 bar-CLTC group presented significantly higher percentage of pre-test failure during fatigue compared to the other groups. Mixed-failure mode was more frequent than adhesive failure. Conclusions: CLTC significantly decreased the SBS values regardless of the air-abrasion pressure used.

• The Journal of Advanced Prosthodontics
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• 제10권2호
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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.

• Restorative Dentistry and Endodontics
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• 제48권2호
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• pp.14.1-14.11
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• 2023

Objectives: This study investigated the effect of an aluminum chloride hemostatic agent on the shear bond strength (SBS) of a universal adhesive to dentin. Materials and Methods: Eighty extracted human molars were trimmed at the occlusal dentin surfaces and divided mesiodistally. According to hemostatic agent application, specimens were randomly allocated into control (C) and hemostatic agent (Traxodent; H) groups. Each group was divided into 4 subgroups according to the adhesive system (n = 20): Scotchbond Multi-Purpose (SBER), Clearfil SE Bond (CLSE), All-Bond Universal etch-and-rinse mode (ALER), and All-Bond Universal self-etch mode (ALSE). SBS was measured for half of the specimens at 24 hours, and the other half were thermocycled in water baths (group T). Fracture surfaces were examined to determine the failure mode. The SBS was measured, and data were analyzed using 1-way analysis of variance, the Student's t-test, and the Tukey honestly significant difference test (p = 0.05). Results: No significant differences in SBS were found between groups C and H for any adhesive system at 24 hours. After thermocycling, a statistically significant difference was observed between CT+ALSE and HT+ALSE (p < 0.05). When All-Bond Universal was applied to hemostatic agent-contaminated dentin, the SBS of H+ALSE was significantly lower than that of H+ALER (p < 0.05). The SBER subgroups showed no significant differences in SBS regardless of treatment and thermocycling. Conclusions: When exposed dentin was contaminated by an aluminum chloride hemostatic agent before dentin adhesive treatment, application of All-Bond Universal in etch-and-rinse mode was superior to self-etch mode.

• 대한소아치과학회지
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• 제45권2호
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• pp.185-194
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• 2018

본 연구의 목적은 타액이나 혈액에 오염된 유치 지르코니아 기성관의 내면을 다양한 세척 방법으로 세척 한 뒤, 레진 시멘트와의 결합력을 비교하고, 열 순환이 결합력에 미치는 효과를 평가하였다. 지르코니아 기성관의 내면과 유사한 상태의 지르코니아 절편($5mm{\times}3mm$)을 아크릴릭 레진에 매몰하였다(n=180). 이 중 160개의 시편을 무작위로 두 군으로 나누어 타액 오염과 혈액 오염을 시행하였다. 양성 대조군은 오염 과정을 거치지 않고 resin cement로 접착을 시행하였고, 음성 대조군은 오염 후 dental unit chair 상의 물로 20초간 세척 후 10초간 건조를 시행하였다. 타액 오염된 시편과 (n=60) 혈액 오염된 시편(n=60)은 각각 세 가지 방법의 세척을 시행하였다. 37% 인산 젤, 상용 세척제(Ivoclean), 2.5% NaOCl을 각 시편에 20초간 적용 후 10초간 물로 세척하고 건조를 시행하였다. 이 후 모든 시편(n=160)에 접착을 시행하였다. 대조군과 각 실험군을 모두 절반으로 나누어 절반은 바로 전단응력을 측정하였고, 절반은 열 순환 과정 후 전단응력을 측정하였다. 타액오염과 혈액오염을 시행한 군 모두에서, 양성 대조군과 상용 세척제, 2.5% NaOCl으로 세척한 군에서 통계학적으로 유의한 차이는 존재하지 않았다. 음성 대조군과 37% 인산 젤로 세척한 군의 전단 결합 강도는 양성 대조군과 비교하였을 때, 유의하게 감소하였다. 열 순환 시행 시 타액 오염을 시행한 군과 혈액 오염을 시행한 모든 군에서 열 순환을 시행하지 않은 군보다 통계적으로 유의하게 낮은 전단 응력 간도를 나타내었다. 유치 지르코니아 기성관 내부의 타액 오염이나 혈액 오염 시, 상용 세척제나 2.5% NaOCl로 세척을 시행하면 원래의 전단응력 값을 얻을 수 있다. 열 순환 시행 시 모든 군에서 유의하게 낮은 전단 응력 값을 보였다.

• 대한소아치과학회지
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• 제45권3호
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• pp.314-323
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• 2018

이 연구의 목적은 3종 시멘트의 전단결합강도를 평가하고 열순환 시행이 전단결합강도에 미치는 영향을 알아보고자 한다. 소아치과에서 사용되는 소아용 기성 지르코니아 전장관($NuSmile^{(R)}$ ZR crown)의 내면과 유사한 디스크 형태의 지르코니아 시편(Zirconia discs)을 제작하였다. 소아용 기성 지르코니아 전장관의 내면과 지르코니아 시편의 표면이 동일하도록 같은 몰드를 이용하여 제작하였으며 주사전자현미경을 통해 유사함을 확인하였다. 60개의 지르코니아 시편과 60개의 유구치 상아질 시편을 3종의 시멘트 $Ketac^{TM}$ Cem Permanent Glass Ionomer Luting Cement(KGI), $RelyX^{TM}$ Luting Plus Cement(RLP), $RelyX^{TM}$ Unicem Self-Adhesive Universal Resin Cement(RUR)에 따라 20개씩 나누고, 열순환 시행 유무에 따라 다시 10개씩 2개의 하위그룹으로 나누었다. 하위그룹 A는 열순환을 시행하지 않았고 하위그룹 B는 5500회의 열순환을 시행하였다. 만능 재료 시험기를 이용하여 전단결합강도를 측정한 후 파절 양상을 주사전사현미경으로 관찰하였다. 지르코니아 시편 및 유구치 상아질 시편에 접착한 시멘트의 전단결합강도는 RUR이 KGI와 RLP보다 높았으며 통계적으로 유의한 차이가 관찰되었다(p < 0.05). RUR의 전단결합강도는 열순환 시행하지 않은 군과 열순환 시행한 군 사이에 통계적으로 유의한 차이가 없었다.