• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.56-62
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• 2000

The purpose of this study was to assess the effects of restorative materials on the marginal leakage of wedge-shaped class V cavity. The study was performed in vitro in 25 defect-free permanent, extracted teeth. Wedge-shaped class V cavities were prepared and then the teeth were randomly selected and restored according to the following. Group A : restoration with Tetric Ceram(composite resin) Group B : restoration with Tetric flow(flowable resin) Group C : restoration with Compoglass after acid etching(compomer) Group D : restoration with Compoglass(compomer) Group E : restoration with Fuji II LC improved(resin-modified GIC) After thermocycling, the specimens were immersed in 5% basic fuchsin solution for 6 hours and sectioned longitudinally through the center of the restoration. The degree of marginal leakage was measured as the extent of dye penetration under the stereomicroscope. The data were analysed using one-way ANOVA. When significant differences found, multiple comparisons were made using Duncan's Multiple Range Test. The results were as follows: 1. The occlusal margins of all groups except for Fuji II LC improved showed lesser leakage than gingival margins and there was statistically significant difference(p<0.05). 2. At the occlusal margins, group A, B showed same marginal leakage scores, and others were decreased as group C, D, E in that order. There were statistically significant difference between group A, Band group D, E, group C and group E(p<0.05). 3. At the gingival margins, group B, C showed same marginal leakage scores, and others were decreased as group A, D, E in that order. But there was statistically significant difference between group B, C and group E(p<0.05). 4. In the Compoglass restoration, acid-etching technique was beneficial for marginal sealing ability at all of margins. But there was no statistically significant difference (p>0.05). In the restorations for wedge-shaped class V cavities, resin restoration with acid etching technique is recommended.

• 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.34 no.2
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• pp.89-96
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• 2018

Purpose: The aim of this study was to evaluate the effect of delayed time, surface treatment, and repair materials on repair of bis-acryl composite resin through comparison of shear bond strength and to evaluate the utility of bis-acryl composite resin repair using polymethyl methacrylate resin. Materials and Methods: A total of 90 bis-acryl composite resin specimens were fabricated and classified into 9 test groups, each of 10 pieces according to delayed time, surface treatment and repair material. The shear bond strength of each specimen was measured using a universal testing machine immediately after fabrication and analyzed using a statistical analysis program (IBM SPSS statistics 20). After the shear bond strength measurement, the fracture surface of the specimen was observed. Results: The highest shear bond strength ($17.54{\pm}3.14MPa$) was observed in the experimental group bonded immediately with a light-curing flowable composite resin using a bonding agent. Conclusion: When repairing bis-acryl composite resin, it is necessary to consider whether to remake according to the delayed time. For effective repair, it is desirable to consider appropriate materials and surface treatment methods according to the site or purpose of use.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.221-232
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• 2006

The purpose of this study was to investigate the effect of step-curing mode on polymerization shrinkage and contraction of composite resin restoration. Class I cavities were prepared on the extracted human premolars. The cavities were ailed with Filtek $Z-250^{TM}$ (hybrid resin, 3M ESPE, USA) and Filtek $flow^{TM}$ (flowable resin, 3M ESPE, USA) and cured with one of the following irradiation modes; Halogen 40sec with continuous curing, LED 10sec with continuous curing, and LED 13sec with step-curing. Contraction stress was measured with strain gauge which was connected to TML $Datalogger^{TM}$ (TDS-102, SOKKI, Japan) and resin-dentin interfaces were observed by scanning electron microscope. The results of present study can be summarized as follows : 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05) 2. $Filtek\;flow^{TM}$ showed lower contraction stress than Filtek $Z-250^{TM}$ regardless of curing modes. 3. LED step-curing mode showed lowest contraction stress in Filtek $Z-250^{TM}$ compared with other curing modes(P<0.05). 4. LED step-curing mode showed lowest contraction stress in $Filtek\;flow^{TM}$ compared with other curing modes(P<0.05), but difference in contraction stress was not so greate as in $Filtek\;Z-250^{TM}$. 5. Polymerization of composite resin by LED light with step-curing mode and halogen light with continuous ode resulted in better marginal sealing than LED light with continuous mode.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.290-296
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• 2018

Purpose: The aim of this study was to evaluate the polymerization ability of resin-based materials used for teeth splinting according to the thickness of cure. Materials and Methods: For this study, the Light-Fix and G-FIX developed for resinous splinting materials and the G-aenial Universal Flo, the high-flowable composite resin available as restorative and splinting material, were used. Ten specimens of the thickness of 2, 3, 4 and 5 mm and 5 mm in diameter for each composite resin (total 120) were prepared. The microhardness of top and bottom surfaces for each specimen was measured by the Vickers hardness testing machine. The polymerization ability of the composite resin for each thickness was statistically analyzed using independent T-test at a 0.05 level of significance. Results: There was no difference of polymerization ability regardless of the thickness in the Light-Fix and G-FIX. The G-aenial Universal Flo showed significantly low polymerization ability from the thickness of the 3 mm (P < 0.05). Conclusion: The Light-Fix and G-FIX, which are resin-based materials used for teeth splinting, are expected to be suitable for light curing up to 5 mm in thickness.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.37.1-37.10
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• 2019

Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.132-135
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• 2005

The purpose of this study was to propose the modified strip crown technique for esthetic restoration of primary anterior teeth using glass fibers. Celluloid crown form(3M, USA), Z100(P shade, 3M, USA). Aeliteflo(Bisco Inc., USA), and Clearfil SE Bond(Kuraray Medical Inc., Japan) were used for this technique. Mesh type of glass fiber(TESCERA Fiber Mesh, Bisco Inc, USA) was used for reinforcing material. After trimming the celluloid crown form, resin adhesive and flowable resin were applied on the pre-shaped glass fiber mesh. That mesh was placed on the lingual surface of inside of celluloid crown form and followed by light activation. Composite resin was filled into the celluloid crown form and put it on a prepared tooth and then light activated and finished the margin. The new modified strip crown technique can provide esthetics and increased durability for restoration of primary anterior teeth.

• Journal of dental hygiene science
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• v.12 no.5
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• pp.477-485
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• 2012

This study evaluate the influence of food staining food and bleaching on the color (CIELAB) and reflectivity of two-way (anterior & posterior) composite resin and flowable composite resin. There were 6 immersion media: kimchi, red pepper paste, blueberry, tea, curry and distilled water. A total of 36 specimens ($11{\times}11{\times}2$ mm) were prepared and immersed in each immersion media for 8 days at $37^{\circ}C$. Their color and reflectivity measured with the spectrophotometer at baseline and every 24 hours. Data from the color change and reflectivity were collected and subjected to statistical analysis by ANOVA, ANCOVA and RM-ANOVA. Curry showed the highest influence on color change and blueberry on brightness (p<0.001) on both resins. Bleaching after polishing made color change more than polishing or bleaching independently on two-way (anterior & posterior) composite resin, but not on flowable composite resin. It was suggested cleaning the mouth after taking curry and blueberry be needed to maintain the original color of composite resin.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.320-326
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• 2020

The aim of this study was to compare compressive strength and microhardness of recently introduced alkasite restorative materials with glass ionomer cement and flowable composite resin. For each material, 20 samples were prepared respectively for compressive strength and Vickers microhardness test. The compressive strength was measured with universal testing machine at crosshead speed of 1 mm/min. And microhardness was measured using Vickers Micro hardness testing machine under 500 g load and 10 seconds dwelling time at 1 hour, 1 day, 7 days, 14 days, 21 days and 35 days. The compressive strength was highest in composite resin, followed by alkasite, and glass ionomer cement. In microhardness test, composite resin, which had no change throughout experimental periods, showed highest microhardness in 1 hour, 1 day, and 7 days measurement. The glass ionomer cement showed increase in microhardness for 7 days and no difference was found with composite resin after 14 days measurement. For alkasite, maximum microhardness was measured on 14 days, but showed gradual decrease.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.533-541
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• 2012

Objectives : The purpose of this study was to evaluate the effects of tooth bleaching agent contained 35% hydrogen peroxide on the color, microhardness and surface roughness of tooth-colored restorative materials. Methods : Four types of tooth-colored restorative materials, including a composite resin(Filtek Z350 ; Z350), a flowable composite resin(Filtek P60 : P60), a compomer(Dyract$^{(R)}$ AP ; DY), and a glass-ionomer cement(KetacTM Molar Easymix ; KM) were used in the study. The specimens($8mm{\times}5mm$) were made by using a customized acrylic mold. Each material was divided into two groups equally(n=40) : experimental group(35% HP) and control group(distilled water). 35% HP group was treated 30 mim/5 days for 15 days. Each 30 minute treatment session consisted of two 15 minute cycles of gel application with 20 second light exposure. The authors measured the color, microhardness, and roughness of the specimens before and after bleaching. The data were analyzed with ANOVA and T-test. Results : 35% HP group showed an apparent color change(${\Delta}E^*$) than control group. In particular, DY and KM showed a noticeable color change and statistically significant differences(p<0.05). 35% HP group showed a reduction in microhardness. Z350 and P60 does not have a statistically significant difference(p>0.05), DY and KM showed a statistically significant difference(p<0.05). Percentage microhardness loss(PML) of control group was 0.6 to 5.5% in the group, 35% HP group was 6.6 to 34.6%. Roughness was increased in 35% HP group after bleaching. Especially DY and KM were significantly increased(p<0.05). Conclusions : Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present.