• The Journal of Advanced Prosthodontics
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• 제9권2호
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• pp.130-137
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• 2017

PURPOSE. The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. MATERIALS AND METHODS. A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength (P<.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. RESULTS. Groups treated with the nano-structured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. CONCLUSION. Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

• Restorative Dentistry and Endodontics
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• 제29권3호
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• pp.219-225
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• 2004

This study evaluated the microshear bond strength of composte resin to teeth bleached with commercial whitening strips and compared with those bleached with home bleaching gel. Twelve extracted human central incisors were cut into pieces and central four segments were chosen from each tooth and embedded in acrylic resin. Four blocks with 12 tooth segments embedded in acrylic resin were acquired and numbered from group one to group four. Group 1 was bleached with Crest Whitestrips, group 2 with Claren, group 3 with Opalescence tooth whitening gel (10％ carbamide peroxide). Group 4 was used as control. The bleaching procedure was conducted for 14 days according to the manufacturer's instructions ; the bleaching strips twice a day for 30 min and the bleaching gel once a day for 2hr. After bleaching, composite resin (Filtek Supreme) was bonded to the enamel surfaces with a self-etching adhesive (Adper Prompt L-Pop) using Tygon tube. Microshear bond strength was tested with a universal testing machine (EZ-test). The data were statistically analysed by one-way ANOVA. The study resulted in no statistical differences in microshear bond strength between the tooth segments bleached with 2 different whitening strips and bleaching gel. It can be concluded that the effect of bleaching with either commercial whitening strips or bleaching gel on enamel is minimal in bonding with self-etching adhesive to composite resin.

• 한국터널지하공간학회 논문집
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• 제7권4호
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• pp.305-311
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• 2005

암반에 건설되는 대단면 터널에서 숏크리트의 부착강도는 암반탈락 방지와 발파진동에 의한 숏크리트 탈락방지에 매우 중요하다. 그럼에도 불구하고 숏크리트 부착강도는 압축강도에 비하여 설계 및 시공단계에서 중요한 요소로 고려되지 않았다. 따라서 본 연구의 목적은 숏크리트 부착강도가 대단면 암반 터널의 안정성에 미치는 영향을 분석하는 것이다. 먼저, Holmgren의 punch-loaded 시험조건을 모사한 수치해석 모델을 이용하여 다양한 부착강도에 대한 매개변수연구를 수행하였다. 그 결과, 숏크리트의 최대지지력은 숏크리트층과 블록간의 부착 강도와 선형 비례관계를 보임을 확인하였다. 또한, 숏크리트층과 굴착면에 부착강도를 고려하는 경우와 기존의 완전부착 조건에 대한 개별요소해석을 수행하여 숏크리트 부착강도의 영향을 검토하였다.

• Elastomers and Composites
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• 제52권4호
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• pp.295-302
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• 2017

Polyurethane dispersion (PUD) polymers were synthesized by using polyether and polyester polyol. The effect of ionomeric centers, r(NCO / OH) values, chain extender process, and chain extender types on the adhesion properties was investigated. In the case of polyether-based PUD, the ionic center, r value, chain extension process and chain extender types were not adjusted even after adjustment. In the case of polyester-based PUD, when the ionic center content was more than 2.5%, the state of adhesive strength was $2.0kgf/cm^2$ or more. On the other hand, the initial adhesive strength was excellent at about $1kgf/cm^2$ when the ionic center content was over 3.5%. When the r value was 1.3 or more, it was found that the initial bonding strength and the state of bonding strength were excellent at about $1kgf/cm^2$ and $2.1kgf/cm^2$ or higher, respectively. An IR spectrum analysis of the synthesized PUD confirmed that PUD was composed of urethane based on the N-H characteristic peak at $3340cm^{-1}$ and the urethane characteristic peak at $1730cm^{-1}$. Moreover, the characteristic peaks of the isocyanate ($2260cm^{-1}$) used in the preparation of the prepolymer were not observed. As a result, the residual -NCO was not observed, and urethane was completely synthesized.

• Restorative Dentistry and Endodontics
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• 제29권2호
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• pp.153-161
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• 2004

This study investigated that the effect of rewetting agent on dentinal microtensile bond strength(${\mu}TBS$). Human molars were sectioned to expose the superficial dentin surfaces. Samples were divided into two groups according to type of adhesives-Single Bond (S) and One-Step (0)], and again subdivided into five groups by different dentin surface treatment-dry for 15s (D), blot dry (BD) or dry for 15s, and rewet with different rewetting agents [distilled water (DW), Gluma Desensitizer (GD) and Aqua-Prep (AP)] for 30s. After application of adhesive, composite resin was built up on the bonding surface. Each tooth was sectioned to obtain stick with $1\textrm{mm}^2$ cross sectional area and the ${\mu}TBS$ was determined by EZ test. In the S group, the mean ${\mu}TBS$ of GD, AP, and BD group was significantly higher than that of DW and D group (p < 0.05), In the O group, the mean, ${\mu}TBS$ of AP, GD, BD and DW group was significantly higher than that of D group (p < 0.05). The data suggested that Gluma Desensitizer and Aqua-Prep could be successfully used as rewetting agents, and Distilled water could be acceptable in aceton based adhesive system only.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.647-656
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• 1999

The purpose of this study was to investigate the shear bond strength and marginal microleakage of composite to enamel and dentin according to different treatment methods when the applied bonding agent was contaminated by artificial saliva. For the shear bond strength test, the buccal and occlusal surfaces of one hundred twenty molar teeth were ground to expose enamel(n=60) and dentin surfaces(n=60). The specimens were randomly assigned into control and 5 experimental groups with 10 samples in each group. In control group, a bonding system(Scotchbond$^{TM}$ Multi-Purpose plus) and a composite resin(Z-100$^{TM}$) was bonded on the specimens according to manufacture's directions. Experimental groups were subdivided into 5 groups. After polymerization of an adhesive, they were contaminated with at artificial saliva on enamel and dentin surfaces: Experimental group 1 ; artificial saliva was dried with compressed air. Experimental group 2 ; artificial saliva was rinsed with air-water spray and dried. Experimental group 3 ; artificial saliva was rinsed, dried and applied an adhesive. Experimental group 4 ; artificial saliva was rinsed, dried, and then etched using phosphoric acid followed by an adhesive. Experimental group 5, artificial saliva was rinsed, dried, and then etched with phosphoric acid followed by consecutive application of both a primer and an adhesive. Composite resin(Z-100$^{TM}$) was bonded on saliva-treated enamel and dentin surfaces. The shear bond strengths were measured by universal testing machine(AGS-1000 4D, Shimaduzu Co. Japan) with a crosshead speed of 5mm/minute under 50kg load cell. Failure modes of fracture sites were examined under stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's test. For the marginal microleakage test, Class V cavities were prepared on the buccal surfaces of sixty molars. The specimens were divided into control and experimental groups. Cavities in experimental group were contaminated with artificial saliva and those surfaces in each experimental groups received the same treatments as for the shear test. Cavities were filled with Z-100. Specimens were immersed in 0.5% basic fuchsin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from the one specimen. Marginal microleakages of enamel and dentin were scored under streomicroscope and averaged from four sections. The data were analyzed by Kruskal-Wallis test and Fisher's LSD. The results of this study were as follows. 1. The shear bond strength to enamel showed lower value in experimental group 1(13.20${\pm}$2.94MPa) and experimental group 2(13.20${\pm}$2.94MPa) than in control(20.03${\pm}$4.47MPa), experimental group 4(20.96${\pm}$4.25MPa) and experimental group 5(21.25${\pm}$4.48MPa) (p<0.05). 2. The shear bond strength to dentin showed lower value in experimental group 1(9.35${\pm}$4.11MPa) and experimental group 2(9.83${\pm}$4.11MPa) than in control group(17.86${\pm}$4.03MPa), experimental group 4(15.04${\pm}$3.22MPa) and experimental group 5(14.33${\pm}$3.00MPa) (p<0.05). 3. Both on enamel and dentin surfaces, experimental group 1 and 2 showed many adhesive failures, but control and experimental group 3, 4 and 5 showed mixed and cohesive failures. 4. Enamel marginal microleakage was the highest in experimental group 1 and there was a significant difference in comparison with other groups (p<0.05). 5. Dentin marginal microleakages of experimental group 1 and 2 were higher than those of other groups (p<0.05). This result suggests that treatment methods, re-etching with 35% phosphoric acid followed by re-application of adhesive or repeating all adhesive procedures, will produce good effect on both shear bond strength and microleakage of composite to enamel and dentin if the polymerized bonding agent was contaminated by saliva.

• 대한의용생체공학회:의공학회지
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• 제16권4호
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• pp.533-542
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• 1995

The present study investigated the effectiveness of pretreatment on dentin bonding. The adhesive resin was 5% 4-methacryloyloxyethyl trimellitate anhydride (4-META) in methyl methacrylate (MMA) combined with poly-MMA powder. Polymerization of this resin was initiated by tri-n-butyl borage (TBB). Ground bovine dentin samples were etched with either an aqueous solution of 10% citric (10-0 solution) (Group I) or aqueous solution of 10% citric acid and 3% ferric chloride(10-3 solution) (Group ll ). After etching, the primer (an aqueous solution of 35% hydroxyethyl methacrylate (HEM- A) and 5% glutaraldehyde was applied on the differently etched surfaces (Group III , Group IV). The 10-0 treatment showed the lowest tensile bond strength, followed by the 10-3 treatment, primer application after the 10-0 treatment and primer application after the 10-3 treatment. The relationship among the surface morphology after pretreatment, fractured surface morphology and tensile bond strength was examined. It revealed that the surface morphology change by different pretreatment influenced the bond strength and the resulting fractured surface morphology. The correlation of tensile bond strength with the fracture morphology was explained.

• 대한기계학회논문집A
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• 제32권7호
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• pp.569-575
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• 2008

In this study, disk type of thermal barrier coating system for gas turbine blade was isothermally aged in the furnace changing exposure time and temperature. For each aging condition, bond tests for three samples were conducted for evaluating degradation of adhesive or cohesive strength of thermal barrier coating system. For as-sprayed condition, the location of fracture in the bond test was in the middle of epoxy which have bond strength of 57 MPa. As specimens are degraded by thermal aging, bond strength gradually decreased and the location of failure was also changed from within top coat at the earlier stage of thermal aging to the interface between top coat and TGO at the later stage due to the delamination in the coating.

• The Journal of Advanced Prosthodontics
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• 제9권6호
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• pp.447-452
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• 2017

PURPOSE. To evaluate the sealing performance of Hybrid Coat and its influence on the shear bond strength of five dentin surface cements. MATERIALS AND METHODS. Six premolars were pretreated to expose the dentin surface prior to the application of Hybrid Coat. The microscopic characteristics of the dentinal surfaces were examined with scanning electron microscopy (SEM). Then, 40 premolars were sectioned longitudinally, and 80 semi-sections were divided into a control group (untreated) and a study group (treated by Hybrid Coat). Alloy restoration was bonded to the teeth specimen using five different cements. Shear bond strength was measured by the universal testing machine. The fracture patterns and the adhesive interface were observed using a stereomicroscope. RESULTS. SEM revealed that the lumens of dentinal tubules were completely occluded by Hybrid Coat. The Hybrid Coat significantly improved the shear bond strength of resin-modified glass ionomer cement (RMGIC) and resin cement (RC) but weakened the performance of zinc phosphate cement (ZPC), zinc polycarboxylate cement (ZPCC) and glass ionomer cement (GIC). CONCLUSION. Hybrid Coat is an effective dentinal tubule sealant, and therefore its combined use with resin or resin-modified glass ionomer cements can be applied for the prostheses attachment purpose.

• Restorative Dentistry and Endodontics
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• 제48권3호
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• pp.30.1-30.11
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• 2023

Objectives: This study verified the possibility of cementing fiberglass-reinforced posts using a flowable bulk-fill composite (BF), comparing its push-out bond strength and microhardness with these properties of 3 luting materials. Materials and Methods: Sixty endodontically treated bovine roots were used. Posts were cemented using conventional dual-cured cement (CC); self-adhesive cement (SA); dual-cured composite (RC); and BF. Push-out bond strength (n = 10) and microhardness (n = 5) tests were performed after 1 week and 4 months of storage. Two-way repeated measures analysis of variance (ANOVA), 1-way ANOVA, t-test, and Tukey post-hoc tests were applied for the push-out bond strength and microhardness results; and Pearson correlation test was applied to verify the correlation between push-out bond strength and microhardness results (α = 0.05). Results: BF presented higher push-out bond strength than CC and SA in the cervical third before aging (p < 0.01). No differences were found between push-out bond strength before and after aging for all the luting materials (p = 0.84). Regarding hardness, only SA presented higher values measured before than after aging (p < 0.01). RC and BF did not present 80% of the maximum hardness at the apical regions. A strong positive correlation was found between the luting materials' push-out bond strength and microhardness (p < 0.01, R² = 0.7912). Conclusions: The BF presented comparable or higher push-out bond strength and microhardness than the luting materials, which indicates that it could be used for cementing resin posts in situations where adequate light curing is possible.