• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.383-386
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• 2003

In this study, the MMA-modified paste mixed waste rubber powder, which has a small elastic modulus and a large modification, was produced by using the soft unsaturated polyester resin(UP) as a binder. Then the adhesive properties according to the matrices in both underwater and air-dry conditions and the hardening shrinkage according to the contents of shrinkage reducing agent(SRA) and of MMA were surveyed. The experimental results show that, regardless of humidity of matrices the adhesive strength of polymer concrete was larger than cement concrete. the adhesive strength of MMA content of 20% was larger than MMA content of 30%. regardless of matrix materials the adhesive strength in water condition were $20{\sim}30%$ comparing with the air-dry condition. The case of MMA content of 20% showed the largest adhesive strength. In the hardening shrinkage experiment, the hardening shrinkage reduced as MMA and SRA contents increased, and the decrease of the hardening shrinkage by SRA was larger.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.7-16
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• 1984

The purpose of this study was to investigate the pulpal responses to adhesive resins as phosphoric ester system: "Clearfil F II" (Composite filling material), "Panavia EX" (Composite cementing Material) and "Silar" (Microfilled Compsoite resin) comparing with Zinc-Oxide-Eugenol cement. Total 70 cavities of the permanent healthy teeth from 5 dogs were prepared and placed with experimental resins and Zinc-Oxide-Eugenol cement as control. The dogs were sarificed at 5 intervals of 3 days, one, two, four, six weeks. The specimens were routinely prepared and stained by Hematoxylin-Eosin. Followings were the results obtained through microscopic examination. 1. In cases of Clearfil F II and Panavia EX without etching and lining, pulp response in the early stage showed more severe vascular congestion and hemorrhage than that of Zinc-Oxide-Engenol cement. 2. The pulp response of totally etched cases was similar to that of unetched cases in the groups of Clearfil F II and Panavia EX. 3. The cases of Clearfil F II and Panavia EX with enamel etching showed no significant histologic change compared to that of total cavity etching. 4. The Silar case with total etching showed retarded tendency of histologic recovery compared to Clearfil F II and Panavia EX group. 5. Generally, pulp responses of experimental groups were not severe and the six week case showed the evidence of a histologic recovery.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.605-611
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• 1995

The purpose of this study was to evaluate effects of time on shear bond strengths of a light-cured glass ionomer cement and chemically cured resin cement to enamel, and to observe the failure patterns of bracket bondings. Shear bond strength of a light-cured glass ionomer cement were compared with that of a resin cement. Metal brackets were bonded on the extracted human bicuspids. Specimens were subjected to a shear load(in an Instron machine) after storage at room temperature for 5 and 15 minutes; after storage in distilled water at $37^{\circ}C$ for 1 or 35 days. The deboned specimens were measured In respect of adhesive remnant index. The data were evaluated and tested by ANOVA, Duncan's multiple range test, and t-test, and those results were as follows. 1. The shear bond strength of light-cured glass ionomer cement is higher than that of resin cement at 5 and 15 minutes. 2. The shear bond strengths of both light-cured glass ionomer cement and resin cement increase with time. There was no significant difference in those of both 1 day group and 35 day group 3. Light-cured glass ionomer cement is suitable as orthodontic bracket adhesives

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.108-114
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• 2015

PURPOSE. The aim of this study was to evaluate effect of different surface treatment methods on the bond strength between aged composite-resin core and luting agent. MATERIALS AND METHODS. Seventy-five resin composites and also seventy-five zirconia ceramic discs were prepared. 60 composite samples were exposed to thermal aging (10,000 cycles, 5 to $55^{\circ}C$) and different surface treatment. All specimens were separated into 5 groups (n=15): 1) Intact specimens 2) Thermal aging-air polishing 3) Thermal aging- Er:YAG laser irradiation 4) Thermal aging- acid etching 5) Thermal-aging. All specimens were bonded to the zirconia discs with resin cement and fixed to universal testing machine and bond strength testing loaded to failure with a crosshead speed of 0.5 mm/min. The fractured surface was classified as adhesive failure, cohesive failure and adhesive-cohesive failure. The bond strength data was statistically compared by the Kruskal-Wallis method complemented by the Bonferroni correction Mann-Whitney U test. The probability level for statistical significance was set at ${\alpha}$=.05. RESULTS. Thermal aging and different surface treatment methods have significant effect on the bond strength between composite-resin cores and luting-agent (P<.05). The mean baseline bond strength values ranged between $7.07{\pm}2.11$ and $26.05{\pm}6.53$ N. The highest bond strength of $26.05{\pm}6.53$ N was obtained with Group 3. Group 5 showed the lowest value of bond strength. CONCLUSION. Appropriate surface treatment method should be applied to aged composite resin cores or aged-composites restorations should be replaced for the optimal bond strength and the clinical success.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.278-286
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• 2013

PURPOSE. The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS. FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS. There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION. All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.7 no.1
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• pp.18-26
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• 1998

The improvement of esthetic dentistry has been accelerated from the development of composite resin and dentin-enamel adhesive since 1980's. The indirect composite resin restorations have more accurate proximal contact point and occlusal form than direct restoration. And the side effect of resin shrinkage is minimal because the amount of composite used in oral cavity is limited in cement space. As a results, marginal leakage, hypersensitivity, secondary caries, and discoloration are significantly diminished. The first generation laboratory composite resin used in indirect resin restoration had been widespread in 1980's and the second generation laboratory composite resins were developed in 1990's. The second generation laboratory composite resins are called Ceramic Polymer. The physical properties of Ceramic Polymer are improved because of high content of inorganic filler, and the esthetics and biocompatibility are better than that of the first generation resin. So the application range using composite resin have been broadened. The purpose of this paper is to introduce Targis & Vectris system that is classified to second generation laboratory composite and to report several cases in which the system was utilized for restoration.

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.490-497
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• 2011

Objectives: This study examined the effect of the uncured dentin adhesives on the bond interface between the resin inlay and dentin. Materials and Methods: Dentin surface was exposed in 24 extracted human molars and the teeth were assigned to indirect and direct resin restoration group. For indirect resin groups, exposed dentin surfaces were temporized with provisional resin. The provisional restoration was removed after 1 wk and the teeth were divided further into 4 groups which used dentin adhesives (OptiBond FL, Kerr; One-Step, Bisco) with or without light-curing, respectively (Group OB-C, OB-NC, OS-C and OS-NC). Pre-fabricated resin blocks were cemented on the entire surfaces with resin cement. For the direct resin restoration groups, the dentin surfaces were treated with dentin adhesives (Group OB-D and OS-D), followed by restoring composite resin. After 24 hr, the teeth were assigned to microtensile bond strength (${\mu}TBS$) and confocal laser scanning microscopy (CLSM), respectively. Results: The indirect resin restoration groups showed a lower ${\mu}TBS$ than the direct resin restoration groups. The ${\mu}TBS$ values of the light cured dentin adhesive groups were higher than those of the uncured dentin adhesive groups (p < 0.05). CLSM analysis of the light cured dentin adhesive groups revealed definite and homogenous hybrid layers. However, the uncured dentin adhesive groups showed uncertain or even no hybrid layer. Conclusions: Light-curing of the dentin adhesive prior to the application of the cementing material in luting a resin inlay to dentin resulted in definite, homogenous hybrid layer formation, which may improve the bond strength.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.327-334
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• 1997

The purpose of this study was to evaluate clinical applicability of light cured glass ionomer cement as a othodontic adhesive. The metal brackets and plastic brackets were bonded with light cured glass ionomer cement(Fuji Ortho $LS^{(R)}$) after polishing with a slurry of pumice, surface conditioning with 10% polyacrylic acid and chemically cured resin(Mono-$Lok2^{(R)}$) after acid etching with 38% phosphoric acid on the extracted human bicuspids. The shear bond strength was tested with a universal testing machine(HGS-100A, Shimadzu Co., Japan) after storage in normal saline at $37^{\circ}C$ or 24 hours and 48 hours. The results were as follows: 1. The shear bond strength of light cured glass ionomer cement group polished with a slurry of pumice was significantly lower than that of chemically cured resin group(P<0.01). 2. The shear bond strength of light cured glass ionomer cement group conditioned with 10% polyacrylic acid was significantly lower than that of chemically cured resin group(P<0.01). 3. The shear bond strength of light cued glass ionorner cement group conditioned with 10% polyacrylic acid was slightly higher than that of light cured glass ionomer cement group polished with a slurry of pumice, but there was no significant difference(P>0.05). 4. There was no significant difference between metal bracket group and plastic bracket group irrelevant off enamel conditioning(P>005). In summary, although the shear bond strength of light cured glass lionomer cement was lower than that of chemically cured resin, it night be clinically applicable.

• Restorative Dentistry and Endodontics
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• v.48 no.3
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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.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.359-365
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• 2013

The aim of this study was to evaluate the effect of temporary restorative and filling material on bonding strength between lithium disilicate glass-ceramic and dentin. 60 extracted human molars were cross-sectioned at occlusal third and were embedded into self-cure acrylic resin. Then the teeth were randomly divided into four groups of 15 each. Lithium disilicate glass-ceramic is cemented to dentin as follows: after no any application of the provisional materials (Group A), after application of ALIKETM (GC America Inc.)(Group B), after application of Luxatemp$^{(R)}$ Automix plus (DMG, Germany)(Group C), after application of Fermit$^{(R)}$ (Ivoclar Vivadent, Leichtenstein)(Group D). After the specimens were stored in distilled water for 24 hours, the shear bond strength of the specimens were measured using UTM (Zwick 1456 41, Zwick, Germany) at a crosshead speed of 1mm/min. The data were analysed by one-way ANOVA and Tukey HSD tests. There were no statistically significant differences of bond strength among the groups. Fracture type was showed mixed type of adhesive and cohesive fracture in most of specimens. Within the limitation of this study, bond strength of adhesive resin cement between lithium disilicate glass-ceramic and dentin was not affected by provisional restorative and filling materials.