• 대한치과보철학회지
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• 제47권1호
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• pp.46-52
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• 2009

연구목적: 최근 임플란트 상부보철물의 주재료로서 티타늄의 수요가 증가하고 있고, 급속도로 발전하고 있는 CAD/CAM (computer - aided design/computer-aided manufacturing) 기술이 접목되어 티타늄을 절삭하여 제작하는 방법이 주목을 받고 있으며 치과 임상에서 점점 그 영역이 넓어지고 있다. 다만, 하나의 티타늄괴를 절삭하여 만드는 방법의 특성상 기계적 유지력을 얻을 수 있는 비드 등을 형성할 수 없고, 통상적인 재료인 금 합금이나 도재용 합금 주조체에 비해 도재와의 결합력도 떨어지는 것이 보완해야 할 점으로 지적되고 있다. 이에 본 연구는 절삭형 티타늄을 이용한 보철물 제작에 많이 사용되고 있는 열중합 의치상 레진, 간접 복합 레진, 도재와 Grade II 순수 티타늄 사이의 결합 강도를 비교 평가해 보고자 하였다. 연구 재료 및 방법: 지름 9 mm, 높이 10 mm의 Grade II 순수 티타늄 원통형 시편 37개를 3군으로 나누어 각각 직경 7 mm, 높이 1 mm의 열중합 의치상 레진 (Lucitone 199, DENTSPLY Trubyte, York, USA), 간접 복합 레진 (Sinfony, 3M ESPE, Seefeld, Germany), 도재 (Triceram, Dentaurum, Ispringen, Germany)와 결합시켰다. 시편은 $5-55^{\circ}C$에서 1000회 열순환 처리 후, 범용 시험기 (Instron, Universal Testing Machine, Model 4465, USA)를 이용하여 1 mm/min의 속도로 하중을 가하여 전단결합강도를 측정하였다. 파절된 단면의 양상을 관찰하고 각 군별 파절양상을 조사하였다. 측정값은 one-way ANOVA와 Scheffe's multiple range test (${\alpha}=0.05$)로 분석하였다. 결과: 열중합 의치상 레진인 Lucitone 199 ($17.82{\pm}5.13\;MPa$)의 결합 강도가 가장 높았으며, 도재인 Triceram ($12.97{\pm}2.11\;MPa$), 복합레진인 Sinfony ($6.00{\pm}1.31\;MPa$) 순으로 감소하였다. Lucitone 199와 Sinfony 군의 파절 양상은 대부분이 부착성 파절인 데에 반해 Triceram 군에서는 복합성 파절이 많았다. 결론: CAD/CAM을 이용한 절삭형 티타늄 구조물 상방에 전장용 심미 재료로는 열중합형 의치상 레진이 가장 강한 결합 강도를 보인다. 기존의 주조체의 유지구 등에서 얻는 강도에 비해 약하고, 부착성 파절이 많은 점 등은 향후 이들 재료와 티타늄간의 결합력을 높이기 위한 보다 많은 연구가 이루어져야 할 것을 시사한다.

• 대한치과기공학회지
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• 제32권3호
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• pp.195-207
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• 2010

Purpose: The purpose of this study was to observe the microstructural changes of surface in the specimens, performing the shear bond strength testing. The currently most used non-precious alloys are nickel-chromium based alloys with or without beryllium. However, their biocompatibility has been questioned concerning possible damages to the health of the patient and professionals involved in the fabrication of prosthesis caused by long exposure to Ni and Be. An option to nickel-chromium alloys is the cobalt-chromium alloy, an alternative that does not sacrifice the physical properties of the metal porcelain systems. Studies in the animals substantially show that the cobalt-chromium alloys are relatively well tolerated, being therefore more biocompatible than the nickel-chromium alloys. Methods: Non-addition Be to nickel-chromium based alloy(Bellabond plus) and cobalt-chromium alloy which has been widely used(Wirobond C) fused with ZEO light porcelain classified control group and cobalt-chromium alloy which is developing alloy of Alphadent company in Korea(Alphadent alloy) fused with ZEO light porcelain classified experimental group. The specimens of $4mm{\times}4mm{\times}0.5mm$ were prepared as-cast and as-opaque to cast body to analyze the mechanical characteristic change, the microstructure of alloy surface. The phase change was used to observe through XRD analysis and OM/SEM was used to observe the surface of specimens as-cast and as-opaque to cast body. Chemical formation of their elements was measured with EDS. Then hardness was measured with Micro Vicker's hardness tester. Shear bond strength test thirty specimens of $10mm{\times}10mm{\times}2mm$ was prepared, veneered, 3mm high and 3mm in diameter, over the alloy specimens. The shear bond strength test was performed in a universal testing machine(UTM) with a cross head speed of 0.5mm/min. Ultimate shear bond strength data were analyzed with one-way ANOVA and the Scheffe's test (P<0.05). Within the limits of this study, the following conclusions were drawn: The X-ray diffraction analysis results for the as-cast and as-opaque specimens showed that the major relative intensity of Bellabond plus alloy were changed smaller than Wirobond C and Alphadent Co-Cr based alloys. Results: Microstructural analysis results for the opaque specimens showed all the alloys increased carbides and precipitation(PPT). Alphadent Co-Cr based alloy showed the carbides of lamellar type. The Vickers hardness results for the opaque specimens showed Wirobond C and Alphadent Co-Cr based alloys were increaser than before ascast, but Bellabond plus alloy relatively decreased. The mean shear bond strengths (MPa) were: 33.11 for Wirobond C/ZEO light; 25.00 for Alphadent Co-Cr alloy/ZEO light; 18.02 for Bellabond plus/ZEO light. Conclusion: The mean shear bond strengths for Co-Cr and Ni-Cr based alloy were significantly different. But the all groups showed metal-metal oxide modes in shear bond strengths test at the interface.

• Restorative Dentistry and Endodontics
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• 제24권3호
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• pp.465-472
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• 1999

The aim of this study was to determine the shear bond properties of four dentin bonding systems to internal cervical dentin, and to investigate the effect of the pretreatment for removing smear layer and position of dentin on shear bond strength of dentin bonding agents. The materials tested in this study were consisted of four commercially available dentin bonding systems[Allbond 2(AB), Clearfil Linerbond 2(CL), Optibond FL(OP), Scotchbond Multi-purpose(SB)], a restorative light-cured composite resin[Z100]J and a chelating agent[RC-prep(RC)]. Fifty-six freshly extracted human molars were used in this study. Dentin specimens were prepared by first cutting the root of the tooth 1mm below the cementoenamel junction with a diamond bur in a high speed handpiece under air-water coolant, and then removing occlusal part at pulp horn level by means of a second parallel section, The root canal areas were exposed by means of cutting the dent in specimens perpendicular to the root axis. Dentin specimens were randomly assigned to two groups(pretreated group, not-pretreated group) based on the pretreatment method of dentin surface. In pretreated group, RC was applied to dentin surface for 1minute and then rinsed with NaOCl. In not-pretreated group, dentin surface was rinsed with saline Each groups were subdevided into four groups according to dentin bonding systems. Four dentin bonding systems and a restorative resin were applied according to the directions of manufacturer. The dentin-resin specimens were embedded in a cold cure acrylic resin, and were cut with a low speed diamond saw to the dimension of $1{\times}1mm$. The cut specimens were divided into three groups according to the position of internal cervical dentin. The shear bond properties of dentin-resin specimens were measured with Universal testing machine (Zwick, 020, Germany) with the cross head speed of 0.5mm/min. From this experiment. the following results were obtained : 1. In case of shear bond strength, there was no significant difference among dentin bonding systems in not-pretreated groups, whereas in pretreated groups, the shear bond strengths of AB and of SB were statistically significantly higher than those of CL and of OP. 2. The shear bond strengths of AB and of SB in pretreated groups were significantly higher than those in not-pretreated groups. 3. The shear bond strengths of radicular layer of OP were higher than those of occlusal layer of OP in not-pretreated groups, and of AB in pretreated groups. The shear bond strengths of radicular layer of AB and of CL in not-pretreated groups were higher than those in pretreated group.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.173-176
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• 1992

The spectroscopic studies of the 5,7-dimethoxycoumarin(5,7-DMC) and 4,5',8-trimethylpsoralen(TMP) and the conformational stability of 5,7-DMC-thymidine, 4,5',8-TMP-thymine were carried out by the CNDO/S and molecular mechanics calculation. Theoretical transition energies and direction of polarizations calculated by the CNDO/S method have been used for the interpretation of the observed results. The calculated absorption spectra of 5,7-DMC are qualitatively similar to experimental ones with their characteristic visible bands. MM2 force field calculation on the possible $C_4-cyclophotoadducts$ formed between 5,7-DMC and thymidine through a cycloaddition. of $C_3$, $C_4$ bond of 5,6-DMC to $C_5$, $C_6$ bond of thymidine showed the most stable photocycloadduct to have the anti-head to tail configuration. The major photoadduct of 4,5',8-TMP-thymine has the cis-anti configuration.

• Restorative Dentistry and Endodontics
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• 제36권4호
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• pp.280-289
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• 2011

연구목적: 본 연구의 목적은 다양한 소수성을 지닌 최신 상아질 접착시스템과 저수축 silorane 레진의 미세인장결합강도를 평가하는 것이다. 연구 재료 및 방법: 36개의 갓 발치된 제3대구치를 이용했다. Low-speed diamond saw를 사용하여 교합면에 평행하게 치관을 잘라 middle dentin을 노출시켰다. 치아를 무작위로 9 group으로 나눴다. Silorane self-etch adhesives (SS), SS + phosphoric acid etching (SS + pa), Adper Easy bond (AE), AE + Silorane system bonding (AE + SSb), Clearfil SE bond (CSE), CSE + SSb, All-Bond 2 (AB2), AB2 + SSb, All-Bond 3 (AB3). 접착제를 적용한 후에 Filtek LS (3M ESPE)를 2 mm씩 3회 적층충전하였다. 각 층은 40s씩 광중합하였다. 0.8 mm ${\times}$ 0.8 mm stick을 Micro Tensile Tester로 1 mm/min cross-head speed의 인장력을 가하였다. 파절양상를 관찰하기 위해 광학현미경을 이용하였다. 5가지 접착제의 소수성정도를 결정하기위해 water sorption test하였다. 결과: silorane 레진과 5가지 접착제의 ${\mu}TBS$: SS, 23.2 ${\pm}$ 6.9 MPa; CSE, 19.4 ${\pm}$ 4.4 MPa; AB3, 30.3 ${\pm}$ 4.0 MPa; AB2와 AE, no bond. Additional layering of SSb: CSE + SSb, 26.2 ${\pm}$ 10.3 MPa; AB2 + SSb, 33.9 ${\pm}$ 7.3 MPa; AE + SSb, no bond. 높은 ${\mu}TBS$는 cohesive failure와 관련있었다. SS는 낮은 가장 낮은 water sorption을 보였고 다음으로 AB3, AE, CSE, AB2 순서였다. AE는 가장 높은 용해도를 나타냈고 다음으로 CSE, AB2였다. 결론: 접착제의 소수성이 증가할수록, silorane 레진의 접착강도도 증가하였다. 비전용접착제 위에 silorane adhesive bonding을 layering하는 것은 AB2 + SSb 그룹에서만 결합강도를 유의하게 증가시켰다. AB3는 SS와 유사한 ${\mu}TBS$ & water sorption을 나타냈다. 따라서 AB3는 siloran resin을 접착시키는데 SS를 대체할만한 경쟁력있는 접착제이다.

• 대한치과보철학회지
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• 제46권5호
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• pp.535-543
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• 2008

최근의 레진 접착시스템은 단계를 줄이고 적용과정을 간편화시키는데 주력하고 있으며, 치면에 bonding 및 conditioning 과정 없이 바로 적용 가능한, one-step의 새로운 자가 접착 레진시멘트 (self-adhesive resin luting cement)들이 소개되어 임상에 사용되고 있다. 이에 본 연구의 목적은 자가 접착 레진시멘트와 기존의 레진시멘트의 상아질에 대한 전단 결합 강도를 비교해보고, 자가 접착 레진시멘트 적용시 치면의 식각 처리 여부가 전단 결합 강도에 미치는 영향에 관하여 알아보고자 하는 것이다. 본 연구를 위해 최근 6개월 내 발치된 비교적 건전한 성인의 대구치 45개를 아크릴릭 레진으로 매몰한 다음, 800 grit SiC연마지로 연마를 시행하여 상아질을 노출시켰다. 15개의 치아를 한 군으로 하여, 세 가지 실험군으로 분류하였다. Group 1) 치면에 아무런 전처리 없이 RelyX Unicem 접착. Group 2) 치면에 인산 산부식 처리 후, RelyX Unicem 접착, Group 3) 치면에 Syntac primet + Syntac adhesive + Heliobond 처리 후 Variolink II 접착. 전처리가 완료된 치아 시편 위에 플라스틱 튜브 (직경 3 mm, 높이 3 mm)를 고정한 다음, 제조사의 지시에 따라 각 레진 시멘트를 혼합하여 링 안을 채우고, 광중합을 시행하였다. 접착이 완료된 시편은 $37^{\circ}C$ 항온수조 (증류수)에서 24시간 동안 보관 후, 만능 시험기를 이용하여 1mm/min의 cross head speed로 결합강도를 측정하였으며, 확대경 하에서 파절 양상을 분류 관찰하고, 주사전자현미경을 이용하여 미세구조를 관찰하였다. 측정결과는 SPSS WIN 12.0 프로그램을 사용하여 분석하였으며 다음과 같은 결과를 얻었다. 1. RelyX Unicem의 상아질에 대한 전단결합강도는 Variolink II와 유의한 차이를 보이지 않았다. 2. 상아질에 대한 인산 산부식 처리는 RelyX Unicem과의 전단결합강도를 낮게 하였다. 3. RelyX Unicem과 Variolink II에서는 혼합 파절의 비율이 컸으며, 전단결합강도가 낮았던 인산 산부식 처리 후 RelyX Unicem을 접착한 경우에서는 전체 시편에서 접착성 파절이 관찰되었다. 결론으로 말하면, 자가 접착 레진시멘트와 기존의 레진시멘트의 상아질에 대한 전단결합강도는 유의한 차이를 보이지 않으며, 인산 산부식 처리는 상아질에 대한 자가 접착 레진시멘트의 전단결합강도를 감소시킨다.

• 대한치과기공학회지
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• 제36권2호
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• pp.83-89
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• 2014

Purpose: This study is to evaluate the effect of modeling liquid on the shear-bond strength between zirconia core and veneering ceramic. Methods: Disk-shaped (diameter: 12.0mm; height: 3.0mm) zirconia were randomly divided into six groups according to the surface conditioning method and whether modeling liquid is used or not to be applied (N=60, n=10 per group): group 1-control group with distilled water(ZD); group 2-control group with modeling liquid(ZM); group 3-airborne particle abrasion with $110-{\mu}m$ $Al_2O_3$(AD) with distilled water; group 4-airborne particle abrasion with $110-{\mu}m$ $Al_2O_3$ with modeling liquid(AM); group 5-liner with distilled water(LD); group $6{\pounds}{\neq}liner$ with modeling liquid(LM). Contact angles were determined by the sessile drop method at room temperature using a contact angle measurement apparatus. The specimens were prepared using dentin veneering ceramics, veneered, 3mm high and 2.8mm in diameter, over the cores. The shear bond strength test was performed in a Shear bond test machine. Load was applied at a cross-head speed of 0.50mm/min until failure. The fractured zirconia surfaces were evaluated by using stereomicroscope (${\times}30$). Collected data were analyzed using SPSS(Statistical Package for Social Sciences) Win 12.0 statistics program. Results: ZD showed the highest contact angle($50.6{\pm}5.4^{\circ}$) and LD showed the lowest value($6.7{\pm}1.3^{\circ}$). Control groups and zirconia liner groups were significantly higher contact angle than liner groups(p<0.05). LD was the highest shear bond strength($43.9{\pm}3.8MPa$) and ZD was the lowest shear bond strength($24.8{\pm}4.9MPa$). Shear bond strengths of control groups and contact angle of liner groups were not significantly different((p>0.05). Liner groups presented adhesive failures. The others groups showed cohesive and adhesive failures. Conclusion: Modeling liquid groups showed lower contact angles and lower shear bond strength compared to those of distilled water groups.

• Restorative Dentistry and Endodontics
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• 제12권2호
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• pp.45-53
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• 1987

The purpose of this study was to evaluate the tensile bond strength between composite resin and the human enamel. Three composite resin systems, two chemical (Clearfil Posterior, and Clearfil Posterior-3) and one light cure (Photo Clearfil-A), used with and without an intermediate resin (clearfil bonding agent), were evaluated under different amounts of load (10g, 200g and 200g for a moment) for in vitro tensile bond strength to acid-eched human enamel. Clinically intact buccal or lingual surfaces of 144 freshly extracted human permanent molars, embedded in acrylic were flattened with No #600 carborundum discs. Samples were randomly assigned to the different materials and treatments using a table of random numbers. Eight samples were thus prepared for each group(Table 2) these surfaces were etched with an acid etchant (Kurarey Co. Japan) in a mode of etching for 30 seconds, washing for 15 seconds, and drying for 30-seconds. During the polymerization of composite resin on the acid-etched enamel surfaces with and without bonding agent 10-gram, 200 gram and temporary 200 gram of load were applied. The specimens were stored in 50% relation humidity at $37^{\circ}C$ for 24 hours before testing. An universal Testing machine (Intesco model No. 2010, Tokyo, Japan) was used to apply tensile loads in the vertical directed (fig 5), and the force required for separation was recorded with a cross head speed of 0.25 mm/min and 20 kg in full scale. The results were as follow: 1. The tensile bond strength was much greater in applying a bonding agent than in not doing that. 2. The tensile bond strength of chemical cure composite resin was higher than that of light cure composite resin with applying on bonding agent on the acid-etched enamel. 3. In case of not applying a bonding agents on the acid-etching enamel, the highest tensile bond strength under 200 gram of load was measured in light cure composite resin. 4. The tensile bond strength under 200-gram of load has no relation with applying the bonding agent. 5. Under the load of 10-gram, There was significant difference in tensile bond strength as applying the bonding agent.

• 대한치과보철학회지
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• 제46권3호
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• pp.261-268
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• 2008

STATEMENT OF PROBLEM: Detachment of the magnetic assembly from the denture base has been a problem in magnetic overdenture patients. PURPOSE: The objectives of this study were to compare the dislodging force by the fixing materials and the designs of the magnetic assembly, and to compare the effect between the fixing materials and the designs of the magnetic assembly. MATERIAL AND METHODS: Two fixing materials, Jet denture repair $acrylic^{(R)}$ and Super-$Bond^{(R)}$ C&$B^{(R)}$ and two types of magnetic assembly designed with or without wing were used. Each magnetic assembly was fixed in the chamber of the denture base resin block ($Lucitone^{(R)}$199) with each fixing material respectively. These specimens were thermocycled 2,000 cycles in the water held at $4^{\circ}C$ and $60^{\circ}C$ with a dwell time of 1 min each time. Each specimen was seated in a testing jig and then a push-out test was performed with a universal testing machine at a cross head speed of 0.5 mm/min to measure the maximum dislodging forces. RESULTS: Comparing the fixing materials, Super-Bond C&$B^{(R)}$ showed superior dislodging force than Jet denture repair $acrylic^{(R)}$. Comparing the design of the magnetic assemblies, the wing design magnetic assembly showed better dislodging force. Combination of the Super-Bond C&$B^{(R)}$ as a fixing material and wing design magnetic assembly revealed a greatest dislodging force. The kind of fixing material was more influential than the type of magnetic assembly. CONCLUSION: The dislodging force of Super-Bond C&$B^{(R)}$ was significantly higher than Jet denture repair $acrylic^{(R)}$. And the dislodging force of magnetic assembly which have wing design was significantly higher than magnetic assembly which have no wing design.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.201-216
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• 1990

A variety of surface pre-treatments have been advocated to prepare the dentin prior to placement of a bonding agent. The purpose of this study was to evaluate the effect of various dentin conditioners upon the degree of resin impregnation to the dentinal tubules and the shear bond strength of a new dentinal bonding agent (Scotchbond 2) used in conjunction with a visible light cured composite (Silux). The healthy eighty human molars extracted due to periodontal or orthodontic reasons were used and randomly divided into five groups. All the grinded dentin surfaces were conditioned with 3% $H_2O_2$, Cavity Cleanser (Columbus/Bayer), Dentin Conditioner (GC Inter. Corp.), Scotchprep (3M Co.) according to the manufacturer's directions. The specimens were then demineralized in 10% HCl for 20 sec. and 24 hrs. in order to observe the resin tags in Hitachi X-450 scanning electron microscope at 25KV. Also, shear strengths were obtained using an Instron Testing Machine with a cross head speed of 1 mm/min. The following results were obtained ; 1. In group treating with Dentin Conditioner and Scotchprep, the resin strings were formed on most of the surfaces and penetrated more than $50{\mu}m$ into the tubules. 2. The inner surface of resin treated with Cavity Cleanser, indicating the resin strings formed partly and penetrated about in depth of $30{\mu}m$. 3. In control and experimental group treated with 3% $H_2O_2$, the resin tags were not formed, if any, penetrated shortly. 4. Shear bond strengths in groups treating with Dentin Conditioner and Scotchprep were statistically significant increase than with 3% $H_2O_2$. (P<0.01). 5. The Scotchprep treatment group was significantly higher in shear strength than groups treated with no conditioning and Cavity Cleanser.(P<0.01) 6. Shear bond strengths evaluated were gradually increase in proportion to the tag length of resin impregnation.