• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.89-99
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• 2003

The purpose of this study was to investigate the bonding of resin- based root canal sealer, AH26 when the sealer was applied as a thin layer between dentine and gutta-percha surface. In this study forty non-caries extracted human molars and resin-based root canal sealer(AH 26, DeTrey/Dentsply, Germany) were used. Disks of gutta-percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for thermoplastic obturation were used and dentin surfaces were treated with 2% NaOCl(Group 1) or 2%NaOCl+17% EDTA(Group 3). Disks of gutta-Percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for conventional obturation were used and dentin surface were treated with 2% NaOCl(Group 2) or 2%NaOCl+17% EDTA(Group 4). Enamel was removed by a horizontal section 1mm below the deepest portion of the central occlusal groove by using a watercooled low speed diamond saw. A second horizontal section was done around cementoenamel junction. Exposed dentin surface was cut to approximately $8{\times}8{\;}mm$ rectangular shape and was ground against 320, 400, 600 grade silicon carbide abrasive paper serially. After grinding, the dentine surface were soaked in a solution of 2% NaOCl for 30 minutes and twenty of specimens were treated with 17% EDTA solution for 1 minute. The treated specimens were washed and dried, Root canal sealer, AH26 was prepared according to the manufacture's instructions The Gutta-percha and dentin surface were coated with a thin layer of the freshly mixed seal or. The specimens were left overnight at room temperature. After their initial set, they were transferred to an incubator at $37$^{\circ}C$ for 72 h. After 72 hours, resin blocks were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strength f3r each stick was measured with Microtensile Tester Failure patterns of the specimens at the interface between gutta-percha and dentin were observed under the SEM(x1000) and Stereomicroscope (LEICA M42O, Meyer Inst., TX U.S.A) at 1.25 x25 magnification. The results were statistically analysed by using a One-way ANOVA and Tukey's test. The results were as follows; 1. Tensile bond strengths($mean{\pm}SD$) were expressed with ascending order as follows: Group 1, $3.09{\pm}$ 1.05Mpa : Group 2, $6.23{\pm}1.16MPa$ : Group 3, $7.12{\pm}1.07MPa$ : Group 4, $10.32{\pm}2.06MPa$. 2. Tensile bond strengths of the group 2 and 4 used disks of gutta-percha for conventional obturation were significantly higher than that of the group 1 and 3 used fir thermoplastic obturation. (p < 0.05). 3. Tensile bond strengths of the group 3 and 4 treated with 2% NaOC1+17% EDTA were significantly higher than that of the group 1 and 2 treated with 2% NaOCl. (p < 0.05). 4. In analysis of failure patterns at the interface between sealer and gutta-percha, there were observed 49 (61%)cases of adhesive failure patterns and 31 (39%) cases of mixed failures patterns.

• Restorative Dentistry and Endodontics
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• v.26 no.4
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• pp.332-340
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• 2001

Flowable composite resin has lower filler content, increased flow, and lower modules of elasticity. It is suggested that flowable composite resin can be bonded to the tooth structure intimately and absorb or dissipate the stress. Therefore, it may be advantageous to use flowable composite resin for the base material of class II restoration and for the class V restoraton. The purpose of this study was to evaluate the microleakage and shear bond strength of four flowable composite resins (Aeliteflo, Flow-It, Revolution, Ultraseal XT Plus) compared to Z100 using Scotchbond Multi Purpose dentin bonding system. To evaluate the microleakage, notch-shaped class V cavities were prepared on buccal and lingual surfaces of 80 extracted human premolars and molars on cementum margin. The teeth were randomly divided into non-thermocycling group (group 1) and thermocycling group (group 2) of 40 teeth each. The experimental teeth of each group were randomly divided onto five subgroups of eight samples (sixteen surfaces). The Scotchbond Multi-Purpose and composite resin were applied for each group following the manufacturer's instructions. the teeth of group 2 were thermocycled five hundred times between 5$^{\circ}C$ and 55$^{\circ}C$. The teeth of group 2 were placed in 2% methylene blue dye for 24 hours, then rinsed with tab water. The specimens were embedded in clear resin, and sectioned longitudinally with a diamond saw. The dye penetration on each of the specimen were observed with a stereomicioscope at $\times$20 magnification. To evaluate the shear bond strength, 60 teeth were divided into five groups of twelve teeth each. The experimental teeth were ground horizontally below the dentinoenamel junction, so that no enamel remained. After applying Scotchbond Multi-Purpose on the dentin surface, composite resin was applied in the shape of cylinder. The cylinder was 4mm in diameter and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. After shear bond strength measurement, mode of failure was evaluated with a stereomicroscope at $\times$30 magnification. All data were statistically analyzed by One Way ANOVA and Student-Newman-Keuls method. The correlation between microleakage and shear bond strength was analyzed by linear regression. The results of this study were as follows ; 1. In non-thermocycling group, the leakage value of Z100 was significantly lower than those of flowable composite resins at the enamel and dentin margin, margin, except that Revolution showed the lower leakage value than that of Z100 at the dentin margin (p<0.05). 2. In thermocycling group, the leakage values of Z100 and Ultraseal XT Plus were lower than those of other subgroup at the enamel and dentin margin, except that Flow-It showed the lower leakage value than that of Ultraseal XT Plus at the dentin margin (p<0.05). 3. The leakage value of Z100 and Ultraseal XT Plus in thermocycling group were not higher than that in non-thermocycling group at the enamel margin. The leakage value of Z100 in thermocycling group was not higher than that in non-thermocycling group at the dentin margin (p<0.05). 4. As for the shear bond strength measurement, there were no statistically significant differences among groups (p<0.05). The shear bond strengths given in descending order were as follows: Z100(16.81$\pm$2.98 MPa), Flow-It(14.8$\pm$4.43 MPa), Aeliteflo(14.34$\pm$3.69 MPa), Revolution(13.46$\pm$4.23 MPa), Ultraseal XT Plus(12.83$\pm$3.16 MPa). 5. Failure modes of all specimens were adhesive failures. 6. There was no correlation between microleakage and shear bond strength.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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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.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.280-289
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• 2011

Objectives: The purpose of this study was to evaluate ${\mu}TBS$ (microtensile bond strength) of current dentin bonding adhesives which have different hydrophobicity with low-shrinkage silorane resin. Materials and Methods: Thirty-six human third molars were used. Middle dentin was exposed. The teeth were randomly assigned to nine experimental groups: 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). After adhesive's were applied, the clinical crowns were restored with Filtek LS (3M ESPE). The 0.8 mm ${\times}$ 0.8 mm sticks were submitted to a tensile load using a Micro Tensile Tester (Bisco Inc.). Water sorption was measured to estimate hydrophobicity adhesives. Results: ${\mu}TBS$ of silorane resin to 5 adhesives: SS, 23.2 MPa; CSE, 19.4 MPa; AB3, 30.3 MPa; AB2 and AE, no bond. Additional layering of SSb: CSE + SSb, 26.2 MPa; AB2 + SSb, 33.9 MPa; AE + SSb, no bond. High value of ${\mu}TBS$ was related to cohesive failure. SS showed the lowest water sorption. AE showed the highest solubility. Conclusions: The hydrophobicity of adhesive increased, and silorane resin bond-strength was also increased. Additional hydrophobic adhesive layer did not increase the bond-strength to silorane resin except AB2 + SSb. All-Bond 3 showed similar ${\mu}TBS$ & water sorption with SS. By these facts, we could reach a conclusion that All-Bond 3 is a competitive adhesive which can replace the Silorane adhesive system.

• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.309-323
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• 2009

In this study we evaluated the influence of both the thickness of residual enamel and the color of the composite resins applied to lingual surface on the labial surface color. Background plates were made by randomly (A1, A2, A6D, B1, B2, B3, C1, C2, C6D) selected colors of Filtek Supreme (3M ESPE, St. Paul, U.S.A.) composite resin. Crown portion of 9 maxillary central incisors were cut off and embedded with acrylic resin except labial surface. Samples of average thickness of 2.2 mm were obtained after cutting it in a thickness of 2.5 mm from the labial surface and sandpaper polish. The shade of composite resin background was measured using Spectrophotometer ($Spectrolino^{(R)}$, GretagMacbeth, Regensdorf, Switzerland). And CIE $L^{\ast}a^{\ast}b^{\ast}$value of 2.2 mm thickness tooth samples were measured on the 9 composite resin backgrounds. And then, the cutting side of tooth samples was ground to the extent of 1.9 mm, 1.6 mm, 1.3 mm, 1.0 mm and placed on composite resin backgrounds and measured $L^{\ast}a^{\ast}b^{\ast}$values with the same method. In all samples, $L^{\ast}$value and $b^{\ast}$value seemed to have a tendency of decreasing as thickness of tooth sample becomes thinner regardless of background colors (p < 0.05). But, $a^{\ast}$value didn't show the significant differences depending on the thickness.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.390-398
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• 2000

The purpose of this study was to evaluate the apical fitness of non-standardized gutta-percha cones in root canals prepared with rotary Ni-Ti root canal instruments of various tapers and apical tip sizes. Simulated sixty curved root canals of plastic blocks were prepared with crown-down technique using rotary root canal instruments of Maillefer ProFile$^{(R)}$ .04 and .06 taper (Maillefer Instrument SA, Switzerland). Specimens were divided into six groups and prepared as follows: Group 1, prepared up to size 25 of .04 taper ; Group 2, prepared up to size 30 of .04 taper ; Group 3, prepared up to size 35 of .04 taper ; Group 4, prepared up to size 25 of .06 taper ; Group 5, prepared up to size 30 of .06 taper ; Group 6 ; prepared up to size 35 of .06 taper. After cutting off the coronal portion of plastic, blocks perpendicular to the long axis of the canal with the use of a diamond saw, apical 5mm of canal space was analyzed. Prepared apical canal spaces were duplicated using rubber base impression material to evaluate two dimensional total area of apical canal space. Various sized gutta-percha cones were applied in the 5mm-apical canal space, which were size 25, size 30 and size 35 standardized gutta-percha cone, Diadent Dia-Pro ISO-.04$^{TM}$ and .06$^{TM}$(Diadent, Korea), and medium-fine (MF), fine (F), fine-medium (FM) and medium (M) sized non-standardized gutta-percha cones (Diadent, Korea). Coronal excess gutta-percha were cut off with a sharp blade. Photographs of impressed apical canal spaces and gutta-percha cones were taken with a CCD camera under a stereomicroscope and stored in a computer. Areas of the total canal space and gutta-percha cones were calculated using a digitalized image analysing program, CompuScope (Sungjin Multimedia Co., Korea). Ratio of apical fitness was obtained by calculating the area of gutta-percha cone to the total area of the canal space. The data were analysed statistically using One-way Analysis of Variance and Duncan's Multiple Range Test. The results were as follows: 1. In canals prepared up to size 25 ProFile$^{(R)}$ of .04 taper, non-standardized MF and F cones occupied significantly more canal space than Dia-Pro ISO-.04$^{TM}$ or size 25 standardized ones (p<0.05). 2. In canals prepared up to size 30 ProFile$^{(R)}$ of .04 taper, non-standardized F cones occupied significantly more canal space than Dia-Pro ISO-.04$^{TM}$ or size 30 standardized ones (p<0.05), and non-standardized MF cones occupied more canal space than size 30 standardized ones (p<0.05). 3. In canals prepared up to size 35 ProFile$^{(R)}$ of .04 taper, there was no significant difference in canal space occupation among non-standardized MF and F, size 35 standardized, and Dia-Pro ISO-.04$^{TM}$ cones (p>0.05). 4. In canals prepared up to size 25 ProFile$^{(R)}$ of .06 taper, non-standardized MF and F cones occupied significantly more canal space than Dia-Pro ISO-.06$^{TM}$, or size 25 standardized ones (p<0.05), and Dia-Pro ISO-.06$^{TM}$, cones occupied significantly more space than size 25 standardized ones (p<0.05). 5. In canals prepared up to size 30 ProFile$^{(R)}$ of .06 taper, non-standardized FM cones occupied significantly more canal space than Dia-Pro ISO-.06$^{TM}$ or size 30 standardized ones (p<0.05), and non-standardized F cones occupied significantly more canal space than size 30 standardized ones (p<0.05). 6. In canals prepared up to size 35 ProFile$^{(R)}$ of .06 taper, non-standardized M and FM, Dia-Pro ISO-.06$^{TM}$ occupied significantly more canal space than size 35 standardized ones (p<0.05). In summary, in both canals prepared with .04 or .06 taper ProFile$^{(R)}$, non-standardized cones showed better fitness than Dia-Pro ISO$^{TM}$ or standardized ones, which was more characteristic in smaller canals.