• Restorative Dentistry and Endodontics
• /
• 제20권1호
• /
• pp.362-371
• /
• 1995

The purpose of this study was to evaluate the shear bond strength between composite resin and glass ionomer cement according to surface treatment methods of glass ionomer cement. Sixty round acrylic cylinders were fabricated. And then, a round undercut cavity(8 mm diameter, 2.5mm depth) was prepared in the center of the every acrylic cylinder. After all cavities were restored by using light-cured glass ionomer cement. A total of sixty acrylic cylinders restored with glass ionomer cement were divided into 4 groups according to surface treatment methods of glass ionomer cement. The surface treatment of each group were as follows : control group : no treatment Group 1 : acid etching Group 2 : sandblasting Group 3 : air-podwer abrasive polishing The composite resin was bonded to glass ionomer cement of each specimens. And the shear bond strength was tested with a universal testing machine at a cross-head speed of 1mm/min and 500kg in full scale. The results were as follows : 1. The sandblasting group(group 2) had the highest shear bond strength with $272.50{\pm}24.96\;kg/cm_2$ and the acid etching group(group 1) had the lowest shear bond strength with $192.89{\pm}29.32kg/cm_2$. 2. The no treated group(control group) had higher shear bond strength than acid etching group(group 1) (p<0.05). 3. The sandblasting group(group 2), air-powder abrasive polishing group(group 3) and no treated group(control group) had higher shear bond strength than the acid etching group(group 1) (p<0.05). 4. The sandblasting group(group 2) and air-powder abrasive polishing group(group 3) had higher shear bond strength than the no treatment group(control group), but there was not significant(p>0.05).

• Restorative Dentistry and Endodontics
• /
• 제19권2호
• /
• pp.447-459
• /
• 1994

The purpose of this study is to evaluate of shear bond strength of light-curing composite resin to light-curing glass ionomer cement. Composite resin and glass ionomer cement have been widely used as an esthetic filling materials in dental clinics. To achieve better clinical results, sandwich technic was developed with conpensating for disadvantages of these two materials. Especially, light-curing glass ionomer cement provided greately improved bonding strength of teeth or composite resin, and then excellent clinical results can be acquired. In this study, 6 commercial light-curing glass ionomer cements(3 commercial restorative materials : Fuji II LC, Variglass VLC, Vitremer, and 3 commercial lining materials : Fuji Lining LC, Baseline VLC, Vitrebond) were devided two groups. According to manufacturer's appointment, no surface treatment was referred to N groups. Supposing. of clinical practice, surface grinding with water spray at 320 grit sand paper, 40 seconds etching with 37% phosphoric acid, 20 seconds washing, 20 seconds air drying was referred to N groups. Totally 12 experimental groups were devided, and all 120 specimens from 10 specimens of each groups were made. After light-curing composite resin was bonded to light-curing glass ionomer cement, shear bond strength was tested by Instron universal testing machine between glass ionomer cement and composit resin. The data were analyzed statistically by Student's t-test and ANOVA. The obtained results were as follows; 1. In light-curing glass ionomer cement, restorative materials showed higher shear bond strength to composite resin than lining materials(p<0.05). 2. Variglass VLC of restorative material group and Baseline VLC of lining material group have highest shear bond strength to composite resin(p<0.001). 3. In light-curing glass ionomer cement, surface grinding and acid etching reduced shear bond strength to composite resin(p<0.001)}. 4. VGN group 1s highest shear bond strength to composite resin, VBE group is lowest shear bond strength to composite resin(p<0.001).

• Restorative Dentistry and Endodontics
• /
• 제15권1호
• /
• pp.165-173
• /
• 1990

The purpose of this study was to measure the effect of two commercially available composite resin systems and GC dentin cement on the shear bond strength of the etched porcelain to enamel and dentin. The specimens were divided into six groups, and each group was as follows. Group I : etched enamel-dentin/enamel bonding agent-CHOICE-unfilled resin-silane-etched porcelain Group II : etched enamel-Scotchbond 2-Silux-unfilled resin-silane-etched porcelain. Group III : dentin-dentin/enamel bonding agent-CHOICE-unfilled resin-silane-etched porcelain Group IV : dentin-Scotchbond 2-Silux-unfilled resin-silane-etched porcelain Group V : dentin-GC dentin cement-dentin/enamel bonding agent-CHOICE-unfilled resin-silane-etched porcelain Group VI : dentin-GC dentin cement-Scotchbond 2-Silux- unfilled resin-silane-etched porcelain Following polymerization. the specimens were stored in 100% humidity for 24 hours before testing. Shear bond strength was measured with Instron universal testing machine. The results obtained were as follows; 1. The shear bond strength of the etched porcelain to enamel was greater than that of the etched porcelain to dentin. 2. The shear bond strength of Silux-Scotchbond 2 to dentin was greater than that of CHOICE-dentin/enamel bonding agent. 3. There was no significant difference in shear bond strength to dentin between the groups lined with GC dentin cement. 4. The shear bond strength of Silux-Scotchbond 2 to dentin was greater than that of the groups lined with GC dentin cement. 5. There was no significant difference in shear bond strength to dentin between the groups lined with GC dentin cement and the group directly bonded with CHOICE-dentin/enamel bonding agent.

• Restorative Dentistry and Endodontics
• /
• 제18권1호
• /
• pp.114-121
• /
• 1993

The purpose of this study was to evaluate the effect on treatment methods to shear bond strength between composite resin and amalgam when the alloy surface was finished with a diamond wheel or an sandblaster. Forty round acrylic cylinders were fabricated with a diameter of 33mm and a height of 20mm to fit into the device used during shear bond strength testing. A round undercut cavity (diameter, 8mm: depth, 2.5mm) was prepared in the center of the acrylic surface and the cavity was restored using a amalgam. A total of 40 acrylic cylinders with amalgam were divided into 4 groups according to treatment method. The group treatment were as follows : Group 1 : acid etching after finishing the amalgam with diamond wheel Group 2 : no acid etching after finishing the amalgam with diamond wheel Group 3 : acid etching after sandblasting the amalgam Group 4 : no acid etching after sandblasting the amalgam The shear bond strength of composite resin bonded to amalgam of each specimen was tested with a universal testing machine at a crosshead speed of 0.5mm/min and 500kg in full scale. The results were as follow: 1. After diamond finishing, the non-acid etching group had highest shear bond strength with 7.29kg/$cm^2$ and after sandblasting, the acidetching group had lowest shear bond strength with 4.49kg/$cm^2$. 2. In both diamond finishing and sandblasting group, acid etching of the roughened amalgam surface decreased the shear bond strength. 3. The group treated with a diamond wheel had higher shear bond strength those treated with an sandblaster but there was not significanat.

• 대한치과교정학회지
• /
• 제24권4호
• /
• pp.957-967
• /
• 1994

The purpose of this study was to evaluate the effects of different bases of ceramic brackets on shear bond strength and to observe failure patterns of bracket bondings. Lower bicuspid brackets whose bases designed for the macromechanical and silane treated chemical bonding those for silane treated chemical bonding, those for micromechanical bonding, and those for macromechanical bonding were tested as experimental groups, and foil mesh-backed metal brackets as a control group. All the brackets were bonded with $Mono-Lok\;2^{(TM)}$ on the labial surface of extracted human lower bicuspids after etching the enamel with $38\%$ phosphoric acid solution for 60 seconds. The shear bond strengths were measured on the universal test machine after 24 hours passed in the $37^{\circ}C$ water bath. The gathered data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. The shear bond strengths of brackets for macromechanical and chemical bonding, those for chemical bonding, and those for micromechanical bonding were not different (p>0.05), but showed statistically higher than those of metal bracket and those of ceramic bracket for micromechanical bonding(p<0.05). The shear bond strengths of ceramic bracket for micromechanical bonding showed statistically lower than those of metal bracket(p<0.05). The enamel fractures and/or ceramic bracket fractures were observed in the cases of higher bond strength than that of metal bracket. These results supported that silane treated base of ceramic bracket show higher shear bond strength than that of metal bracket, and suggested that micromechanical form of ceramic bracket bases show higher shear bond strength than that of macromechanical form.

• 한국도로학회논문집
• /
• 제14권5호
• /
• pp.31-45
• /
• 2012

PURPOSES: In Korea, rapid maintenance of distressed concrete pavement is required to prevent traffic jam of the highway. Asphalt concrete overlay has been used as a general maintenance method of construction for aged concrete pavement. AC overlay on existing concrete pavements experience various early distresses such as reflection crack, pothole and rutting, due to different physical characteristics between asphalt overlay and existing concrete pavement. Bonded concrete overlay(BCO) is a good alternative since it has advantages that can reduce various distresses during the service life since overlay material has similar properties with existing concrete pavements. Recently, BCO which uses the ultra rapid harding cement has been applied for maintenance of highway. BCO has advantage of structural performance since it does monolithic behave with existing pavement. Therefore, it is important to have a suitable bond strength criteria for securing performance of BCO. Bond strength criteria should be larger than normal tensile stress and horizontal shear stress occurred by traffic and environmental loading at bond interface. Normal tensile stress and horizontal shear stress need to estimated for the establishment of practical bond strength criteria. METHODS: This study aimed to estimate the bond stresses at the interface of BCO using the three dimensional finite element analysis. RESULTS: As a result of this study, major failure mode and maximum bond stress are evaluated through the analysis of normal tensile stress and horizontal shear stress for various traffic and environmental load conditions. CONCLUSIONS: It was known that normal tensile stresses are dominated by environmental loading, and, horizontal shear stresses are dominated by traffic loading. In addition, bond failure occurred by both of normal tensile stresses and horizontal shear stresses; however, normal tensile stresses are predominated over horizontal shear stresses.

• Restorative Dentistry and Endodontics
• /
• 제25권4호
• /
• pp.550-560
• /
• 2000

In this study, shear bond strength of two bonding systems were measured and appearance of dentin surfaces were observed with SEM according to the storage time of eugenol on dentin surface, thus evaluated the effect of eugenol on bond strength of two dentin bonding systems. Control groups were directly bonded to dentin surface with One Step, Prime & Bond 2.1. Experimental groups were divided into experimental I and II according to dentin bonding agents. After eugenol application, dentin surfaces were bonded with One Step and Prime & Bond 2.1 according to the each storage time of immediately, 3min, 24hour, 48hour and 1week, and then control and experimental groups were filled with light cured composite resin(Z-100). After 24 hours water storage at $37^{\circ}C$, all samples were subjected to a shear load to fracture at a cross head 1.0mm/min with Instron universal testing machine(No. 4467). Etched dentin surface storaged for each time of immediately, 3min, 24hour, 48hour and 1 week after eugenol application were observed under Scanning Electron Microscope(Hitachi S-2300) at 20kvp. The data were evaluated statistically with two-way ANOVA and Tukey's HSD. The results were as follows; 1. Shear bond strengths were higher in control groups than in the experimental groups. 2. As storage time was increased after eugenol application, the shear bond strengths were decreased in experimental groups. 3. In experimental I, II the shear bond strengths were the lowest in which storage time was 1 week after eugenol application. 4. As storage time was increased after eugenol application, etched dentin surfaces showed obstructed dentinal tubule.

• 대한치과교정학회지
• /
• 제27권5호
• /
• pp.781-789
• /
• 1997

본 연구는 교정치료를 위해 최근에 발거된 소구치 65개를 대상으로 발거직후 부착된 이물질을 제거하고 생리식염수에 담구어 보관한 후 법랑질을 퍼미스 및 $38\%$ 인산으로 표면 처리하고 불소가 유리되는 교정용 전색제로는 광중합형 FluoroBond, 광중합 접착제로는 Transbond, 화학중합 접착제로는 Mono-Lok 2를 선정하여 1차 부착 및 재부착시의 전단결합강도를 만능강도시험기로 측정함으로서, 치아우식 예방 및 진행 억제효과를 지닌 불소가 유리되는 교정용 전색제가 광중합형 및 화학중합형 교정용 접착제의 전단결합강도에 미치는 영향과 재부착에 의한 전단결합강도의 변화를 규명하고, 광중합형 접착제와 화학중합형 접착제 사이의 전단결합강도를 비교하여 다음의 결론을 얻었다. 1. 1차부착에 의한 전단결합강도의 크기는 Mono-Lok2군(11.84MPa), Trans bond군(10.75MPa), Light cured FluoroBond+Mono-Lok 2군(9.69MPa), Light cured FluoroBond+Transbond군(9.39MPa)순이었다. 2. 재부착에 의한 전단결합강도의 크기는 Transbond군(7.40MPa), Light cured FluoroBond+Transbond군(6.48MPa), Mono-Lok 2군(5.89MPa), Light cured FluoroBond+Mono-Lok 2군(5.15MPa)순이었다. 3. 불소가 유리되는 교정용 전색제를 적용한군과 적용하지 않은 군 모두에서 화학중합형 접착제가 광중합형 접착제보다 높은 전단결합강도를 보였으나 통계학적으로 유의한 차이는 없었다(p>0.05). 4. 불소가 유리되는 교정용 전색제를 적용한군과 적용하지 않은 군 모두에서 재부착된 광중합형 접착제가 재부착된 화학중합형 접착제보다 높은 전단결합강도를 보였으나 통계학적으로 유의한 차이는없었다(p>0.05). 5. 1차 부착된 군에 비해 재부착된 모든 군에서 전단결합강도가 현저하게 감소되었으며, 통계학적으로 유의한 차이를 보였다(p<0.05 p<0.001). 이상의 결론을 종합해볼 때 임상적으로 브라켓의 전단결합강도에 경향을 미치지 않는 불소가 유리되는 교정용 전색제를 치아 협면에 적용하여 불소의 유리에 의한 치아우식 예방 및 억제효과를 기대하는 것이 필요할 것으로 생각된다.

• 대한치과교정학회지
• /
• 제28권6호
• /
• pp.955-974
• /
• 1998

적절한 전단접착강도를 가지면서 법랑질손상과 브라켓파절을 적게 일으키는 브라켓-접착제의 그룹을 찾아내기 위하여 전단접착강도, 법랑질손상, 브라켓탈락양상, 브라켓 주위의 밀봉과 법랑질-접착제-브라켓 사이의 긴밀도를 연구하였다. 교정치료 목적으로 발치한 240개의 치아를 각각 10개씩 24개의 군으로 나누어서 브라켓을 접착한 후 48시간 후에 전단접착강도를 측정하고 브라켓 탈락 양상을 조사하였다. 또한 브라켓 주위의 밀봉과 법랑질-접착제-브라켓 사이의 긴밀도를 평가하기 위하여 브라켓이 접착된 치아를 반으로 자른 후 주사전자현미경상에서 관찰하였다. 6종류의 브라켓과 4종류의 접착제가 사용되었으며 브라켓은 Image, Plastic, Crystaline, Fascination, Transcend, metal bracket을 사용하였으며 접착제로는 No-mix, Light-Bond, OrthoLC, Superbond C&B가 사용되었다. 이와같은 연구로부터 다음과 같은 결론을 내렸다. 1. 전단접착강도는 Fascination-Light Bond 군에서 36.58 Kg(410.07 Kg/$cm^2$)으로 가장 높았으며 Image-OrthoLC 군에 서 8.93 B◎ (75.51 Kg/$cm^2$)으로 가장 낮았다. OrthoLC를 접착제로 사용하였을 때 전단접착강도는 다른 접착제를 사용하였을 때 보다 비교적 낮았다. 2. 접착제의 종류에 관계없이 Fascination bracket의 전단접착강도는 비교적 높았으며 Image, Plastic bracket의 전단접착강도는 비교적 낮았다. Crystaline, Transcend bracket의 전단접착강도는 metal bracket의 전단접착강도와 비슷하거나 낮았다. 3. 전단접착강도와 법랑질 파절, 브라켓 파절은 상관관계가 있었으며, 접착강도가 증가할수록 법랑질 파절과 브라켓 파절은 증가하였다. 4. OrthoLC를 접착제로 사용하였을 때 법랑질 파절과 브라켓 파절은 일어나지 않았으나 Superbond C&B를 접착제로 사용하였을 때는 법랑질 파절과 브라켓 파절의 빈도가 높았다. 5. No-mix, Light-Bond를 접착제로 사용하였을 때 브라켓 주위의 밀봉과 법랑질-접착제-브라켓의 긴밀도는 양호하였다. 접착제의 종류에 관계없이 Ceramic bracket에서 접착제-브라켓의 긴밀도는 양호하였다. 6. 적절한 전단접착강도를 가지면서 법랑질 파절과 브라켓 파절을 일으키지 않는 군은 Crystaline-No mix, Crystaline Light Bond, Crystaline-OrthoLC, metal-No mix, metal-Light Bond, metal-OrthoLC군이였다.

• 콘크리트학회논문집
• /
• 제22권4호
• /
• pp.527-534
• /
• 2010

이 연구에서는 고강도 전단보강근을 사용한 철근콘크리트 보의 부착성능을 향상시키기 위한 간편한 방법을 소개한다. 일반적으로 전단보강근의 항복강도와 보강근비는 철근콘크리트 보의 전단내력에 영향을 미친다. 그러나 철근 콘크리트 보의 부착성능은 보강근의 항복강도에는 큰 영향을 받지 않으므로 고강도 전단보강근을 사용한 경우 부착파괴의 위험성이 있다. 제안된 방법의 구조적 성능을 검증하기 위하여 총 4개의 철근콘크리트 보 실험체를 제작하고 실험하였다. 실험변수는 전단보강근의 항복강도와 보강근비 및 보강형태로 계획하였다. 실험 결과 제안된 방법은 철근콘크리트 보의 부착성능을 효과적으로 향상시킬 수 있음을 확인할 수 있었다.