• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.217-224
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• 2002

The purpose of this study was to evaluate the influence of saliva contamination on the resin bonding of the etched metal retainers. The test samples were made of Verabond, and divided into 3 groups. Retainers in group1 had normally etched metal surfaces. Retainers in group2 had normally etched metal surfaces which were saliva-contaminated for 30 seconds and cleaned with streaming, luke-warm for 1 minute and dried thoroughly. Retainers in group3 had normally etched metal surfaces which were saliva- contaminated for 30 seconds and dried thoroughly without water-cleansing. Each 3 group specimen was watched on SEM. A resin core, 5mm in diameter and 6mm in length, was made of Panavia using Teflon mold on the each specimen. These 3 groups were tested to evaluate shear bond strength, using universal testing machine. The results were as follows : 1. The shear bond strength showed no significant difference between group1 and group2. 2. The shear bond strength showed significant difference between group1 and group3. 3. The shear bond strength significant difference between group2 and group3. 4. Scanning electron microscope photographs of group1 and group2 showed no signs of contamination but of group3 showed somewhat contaminated.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.1
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• pp.81-88
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• 2003

Resin-bonded bridge has been an alternative to conventional bridge, since resin-bonded bridge has many attractive advantages such as minimal tooth preparation, short chair time and low cost over conventional bridge. Unfortunately, however, it was reported that resin-bonded bridge showed high failure rate from debonding of retainer in spite of consecutive advances in preparation and materials. And it was shown that multiple abutments were more likely to fail. The majority of debonding failure was considered due to the mobility of the abutment during function. In this view, recently, modification in resin-bonded bridge design was tried. Single retainer, single pontic. 2-unit cantilevered resin-bonded bridge was applied to clinical performance and was shown as retentive or more retentive than fixed-fixed type resin-bonded bridge. This was consistent with the results of studies in 2-unit cantilevered resin-bonded bridges made with all ceramic, In-ceram. The purpose of this article was to overview principles of design and to analyze clinical results of 2-unit cantilevered resin-bonded bridge in comparison with the reports of fixed-fixed resin-bonded bridge.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.7-16
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• 1987

The purpose of this study was to compare the resin tag length of 3 composite resin cements: Panavia, Compspan, Conclude, and the resin tag length of Panavia cemented to daliva-contaminated enamel using scanning electron microscopy. The following conclusions can be drawn from this study. 1. The resin tag length of panavia was $8.29{\mu}m$, compsan $8.72{\mu}m$, conclude $7.74{\mu}m$, and Panavia cemented to saliva-contaminated enamel $3.92{\mu}m$. 2. No significant difference of resin tag length between Panavia, Comspan and Conclude could be observed. 3. Saliva contamination of etched enamel surface decreases the wettability of composite resin cement.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.243-251
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• 2008

A subgingival crown-root fracture presents a restorative problem to the clinician because restoration is complicated by the need to maintain the sound tooth structures. Forced eruption offers a method of treatment of teeth fractured close to the alveolar crest. Extrusion of such teeth allows elevating the fracture line above the epitherial attachment and so the proper finishing margins can be prepared. The purpose of this case is to report successful tooth restoration using forced eruption in case of crown-root fractures.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.2
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• pp.365-372
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• 1997

This study was executed to measure the shear bond strength of Panavia EX and Panavia 21 when the Ni-Cr-Be alloy castings were cemented to the enamel surfaces with these cements. The cast metal plates of Ni-Cr-Be alloy were sandblasted and cemented to acid etched enamel surface with Panavia EX or Panavia 21. Their shear bond strength were measured with Instron Universal Testing machine. Within the limits of this study, following conclusions were withdrawn. 1. The mean shear bond strength were 26.85.7MPa, in Panavia EX and 28.35.2MPa, in Panavia 21. 2. t-Test revealed no statistical significance between two groups(.05 level) 3. Macroscopically, bond failures were revealed compound fracture at metal and enamel interfaces, in cases of both cements, as the cement attached partly on both metal and enamel surface.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.3
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• pp.437-443
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• 1992

This study was performed to investigate the availability of adhesive resin cement for luting agent of cast crown. The resin cements used in this study were Panavia-Ex(Kuraray Co., Japan) and C & B-Metabond (Parkell Bio-Materials U.S.A.). Zinc phosphate cement was Flecks zinc cement(Mizzy Inc., U.S.A.) The film thickness of cast crown at gingival margin, lateral wall and occlusal surface was observed with measuring microscope(Modek MXT 70 Matsuzawa Seiki Co., Japan) and the retention of cast crown was measured with Instron Universal Test Machine (Instron Engineering Co., U.S.A.) The results were as follows : 1. The value of retention of cast crown was the highest in the use of Panavia-EX, followed by C & B-Metabond and 2inc phosphate cement, respectively. 2. There was no difference in film thickness among the three cements, but the film thickness in all cements was highest at occlusal surface.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.101-108
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• 1987

The purpose of this study was to investigate the pulpal responses of dental adhesive resins. A total of 40 cavities of the permanent healthy teeth from 4 dogs were prepared. In the experimental group, the cavities were etched for 1 minute with citric acid and filled with experimental resins (ie. Super-Bond C & B$^{(R)}$). In the control group, the cavities were filled with calcium hydroxide base materials (ie. Dycal$^{(R)}$) without etching. The dogs were sacrificed at one, two, three and four weeks after the time of filling and the specimens were routinely prepared and stained with Hematoxylin-Eosin. The microscopic findings were as follows: Infiltration of inflammatory cells was not observed in both experimental and control groups. Change in the odontoblastic layer was not observed in all control groups but severe swelling was observed in deep dental pulp tissue of the control two and three week cases. Pulp tissue was recovered with plenty of fibrous component in the control four week case and reparative dentin formation was not occurred in all cases. Slight changes of the odontoblastic layer beneath the cavity were observed in the experimental one week case. In experimental two and three week cases, swelling of deep pulp tissue was increased and localized reparative dentin formation was observed. In the experimental four week case, odontoblastic layer was recovered with regular appearance and fibrous component of the pulp was increased, but reparative dentin formation was not evident.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.05a
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• pp.281-299
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• 2007

IS/IT 분야 실무자가 지니고 있어야 한다고 생각되는 지식과 전문 기술들을 '지식/능력 영역'과 '소프트웨어 전문 기술 영역'으로 구분하여 각각 세부 항목을 명세하였다. 그리고 분류된 두 영역에 대하여 IS/IT 분야 실무자가 생각하는 필요한 지식 및 전문 기술들의 중요도와 IS/IT 전공 교수가 생각하는 IS/IT 실무자에게 필요한 지식 및 전문 기술들의 중요도를 조사하여 두 그룹간의 인식차 비교를 시도하였다. 조사지역은 실무자는 충청지역 및 수도권 지역에 분포하는 SI 업체를 대상으로 이루어 졌다. IS/IT 실무자를 대상으로 한 조사는 실무자 본인의 일장에서 IS/IT 실무자가 갖추어야 된다고 판단되는 지식 및 전문 기술들의 중요도를 측정하였다. 그와 더불어 그들이 수행하는 IS 활동에 대하여 투자한 시간을 기준으로 군집분석을 실시하여 세가지 그룹으로 구분하여 실무자 전체와 세 그룹간의 비교가 가능하도록 조차되었다. 비교 결과, 지식/능력 영역에서는 IS 실무자들이 상대적으로 '하드웨어에 대한 지식', '특정 조직', '운영체제에 대한 지식'에 대해 더 높은 중요도를 부여하고 있는 것으로 나타났다. 소프트웨어 전문 기술 영역에서는 실무자보다 전공교수가 생각하는 중요도가 보편적으로 더 높게 나타났다. 전공 교수는 '프리젠테이션 도구', '객체지향 언어(C++, Java 등)'에 4점 대의 높은 점수를 주어 중요한 것이 무엇인가 하는 인지가 있는 것으로 보이나 실무자 그룹에서는 특별히 중요시 여기는 항목이 명확히 드러나지 않고 보편적인 값이 median 값 주변에 위치하고 있다. 이는 현재 실무자들이 빠르게 변화하고 있는 IS/IT 환경에서 본인의 경력경로 (career path)을 위해 무엇이 중요한 갓인지 아직 명확히 하고 있지 못하는 것으로도 해석이 가능하다. 자세한 비교/분석 및 해석은 현재 진행 중이며, 여러 흥미로운 해석이 가능할 것으로 기대 된다.합형 파괴가 증가하는 경향을 나타내었다. 이상의 결과로, 상아질 접착제의 접착단계/과정이 결합내구성에 영향을 미침을 알 수 있었다. 따라서 접착과정의 단순화가 반드시 접착에 효과적이라고 할 수 없다.는 저작 운동 잔에는 2군에서 Heliomolar가 Pyramid보다 변연적합도가 우수하였고 (p < 0.05) 그 외의 군에서는 유의차가 없었으며, 저작 운동 후에는 모든 군에서 재료간 유의차가 없었다. 각 부위별 변연적합도를 비교하면, 저작 운동 전 Pyramid에서는 교합면 변연에서는 4군이 2군에 비해 높은 변연적합도를 보였고 (p < 0.05), 인접면과 치은면에서는 군 간 유의차를 보이지 않았다. Heliomolar에서는 교합면 변연에서 2, 4군이 1군에 비해 높은 변연적합도를 보였고 (p < 0.05), 인접면과 치은면에서는 군간 유의차를 보이지 않았다. 저작 운동 후 Pyramid에서는 교합면 변연에서는 3군이 1, 2군에 비해 높은 변연적합도를 보였고 (p < 0.05), 인접면과 치은면에서는 군간 유의차를 보이지 않았다. Heliomolar에서는 교합면에서 2, 3, 4군이 1군에 비해 변연적합도가 높았으며 (p < 0.05), 인접면과 치은면에서는 군간 유의차를 보이지 않았다 이번 연구를 통하여 복합레진을 간헐적 광중합시킴으로써 변연적합도가 향상될 수 있음을 알 수 있었다.시장에 비해 주가가 비교적 안정적인 수준을 유지해 왔다고 볼 수 있다.36.4%)와 외식을 선호(29.1%)${\lrcorner}$ 하기 때문에 패스트푸드를 이용하게 된 것으로 응답 하였으며, 남 여 대학생간에는 유의한 차이(p<0.05)가 인정되었다. 응답자의 체형은 ${\ulcorner}$적당하다${\lrcorner}$고 응답한 경우가 가장 많이 이러한 음식을 즐겨 먹었으며(49.5%), 그 다음은 뚱뚱한 경우도 비교적 많이 먹고

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.377-387
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• 2006

The objective of this study was to evaluate the influence of multiple adhesive coatings on the thickness of hybrid and adhesive layer and shear bond strength(SBS) of self-etch adhesives and self-etch primer adhesives. The buccal or lingual crown dentin of extracted human molars was used. Self-etch adhesives or self-etch primer adhesives were applied 1, 2 and 3 times on the dentin before light curing. In another group adhesives were reapplied after light curing first layer. Treated surfaces were prepared to measure the thickness of hybrid and adhesive layer with SEM, and shear bond strength to dentin using an Instron machine. The following results were obtained : 1. The adhesive layers increased with the number of coatings(p<0.05) with all adhesives. Adpor Prompt L-Pop and Xeno III were significantly thinner than self-etch primer adhesives (p<0.05). 2. The thickness of hybrid layers increased with the number of coatings (p<0.05). 3. The shear bonding strength of Unifil Bond and Clearfill SE Bond were higher than Scotchbond Multipurpose Plus and Adpor Prompt L-Pop (p<0.05), and similar with Xeno III. 4. The shear bond strength increased significantly with the number of coatings in Adpor Prompt L-Pop(p<0.05), but decreased at 3 times in AdheSE Bond(p>0.05). 5. In Adpor Prompt L-Pop and Xeno III, the shear bond strength decreased when adhesives were reapplied after curing the first adhesive layer.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.365-376
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• 2007

The purpose of this study was to evaluate the effect of different etching times on microtensile bond strength (${\mu}TBS$) to dentin both initial and after thermocycling with 3 different types of total-etching adhesives. Fifty four teeth were divided into 18 groups by etching times (5, 15, 25 sec), adhesives types (Scotchbond Multipurpose (SM), Single Bond (SB), One-Step (OS)) and number of thermocycling (0, 2,000 cycles). Flat dentin surfaces were prepared on mid-coronal dentin of extracted third molars. After exposed fresh dentin surfaces were polished with 600-grit SiC papers, each specimen was acid-etched with 35% phosphoric acid (5, 15, 25 sec) and bonded with 3 different types of total etching adhesives respectively. Then, hybrid composite Z-250 was built up. Half of them were not thermocycled (control group) and the ethers were subjected to 2,000 thermocycle (experimental group). They were sectioned occluso-gingivally into $1.0\;{\times}\;1.0\;mm^2$ composite-dentin beams and tested with universal testing machine at a crosshead speed of 1.0 mm/min. Within limited data of this study, the results were as follows 1. There was no statistically significant difference in ${\mu}TBS$ between the thermocycled and non-thermocycled groups, except for both SM and SB etched for 25 sec. 2. In thermocycled SM and SB groups, bond strength decreased by extended etching time. In total etching systems, adhesive durability for dentin could be affected by type of solvents in adhesive and etching time. Especially, extended etching time may cause deteriorate effects on bond strength when ethanol-based adhesive was used.