• Proceedings of the KACD Conference
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• 2001.11a
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• pp.558.2-558
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• 2001

The aims of this study are (1) to investigate the relation of irradiation mode, polymerization shrinkage and degree of cure of composite resin and(2) it effect on micorleakage of class V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501 (Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽d, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux R mode.(omitted)

• Imaging Science in Dentistry
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• v.30 no.4
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• pp.243-248
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• 2000

Purpose: The aim of this study was to determine the relative radiopacities of cavity lining materials (Resin-modified Glass Ionomer cement, Compomer and Plowable resin) for posterior composite resin restoration. Material & Methods: Resin-modified glass ionomer cement (Fuji II LC, Vitrebond/sup TM/), Compomers (Dyract /sup (R)/ Compoglass, F2,000, Dyract/sup (R)/ flow Compoglass Flow) and Flowable resins (Tetric/sup (R)/ flow, Aeliteflo/sup TM/ Revolution/sup TM/) were used. Five specimens of 5 mm in diameter and 2 mm thick were fabricated with each material. Human molars were horizontally sectioned 2 mm thick to include both enamel and dentin. The radiopacities of enamel, dentin, cavity lining materials, aluminum step wedge were obtainded from conventional radiograph and NIH image program. Results: All the tested lining materials showed levels of radiopacity the same as or greater than that of dentin. All compomer tested (Dyract, Compoglass, F2,000, Dyract flow, Compoglass Flow) and Vitrebond/sup TM/, Tetric/sup (R)/ flow were more radiopaque than enamel. The radiopacities of Fuji II LC and Revolution/sup TM/ were between enamel and dentin and resin-modified glass ionomer cement, Compomer and Tetric/sup (R)/ flow were greater than those of Revolution/sup TM/, Aeliteflo/sup TM/ or dentin. The level of radiopacity of the tested materials was variable; those with low radiopacity should be avoided in class II restorations, where a clear determination of recurrent caries by the examining clinician could be compromised. Conclusion: Clinician should be able to distinguish these cavity lining materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the lining material from tooth structure.

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.5-19
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• 1989

The purpose of this study was to observe the microleakage of composite resin filling using several glass ionomer cements. The Class V cavities of eighty noncarious human molars were prepared at the cementoenamel juction on the facial and lingual surfaces of each tooth with a No.330 carbide bur in a high speed handpiece. The cavity dimensions were $3.0{\pm}0.5mm$ wide, $2.0{\pm}0.5mm$ high, and $1.5{\pm}0.5mm$ deep and all enamel cavosurface margins were beveled with a No.558 carbide bur in low speed handpiece. The bevel was approximately $45^{\circ}$ and 0.5-1.0mm in width. A total of the 160 cavities was divided into four groups, and then 144 cavities among them were three experimental groups and remaining sixteen cavities were control group. All of the prepared cavities were restored as follows: group 1 : Preparations were restored with there three glass ionomer cements. group 2 : Preparations were restored with a composite resin with three glass ionomer cement bases placed $0.2{\pm}0.1mm$ short of the cavosurface margin. group 3 : Preparations were restored with a composite resin with three glass ionomer cement bases extened to the cavosurface margin. group 4 : As control group, preparations were restored with a composite resin, PALFIQUE. The specimens were then thermocycled in a range of $6^{\circ}C-60^{\circ}C$ and immersed in a bath of 2.0% aqueous basic fuchsin solution for 24 hours. Dye penetration was read on a scale of 0 to 4 by Tani and Buonocore's method. The following conclusions were derived from the results obtained; 1. All groups showed significantly more leakage at the gingival margins than at the occlusal margins(p<0.0005). 2. At the gingival margins, group 1 showed less leakage than group 3(p<0.01) and group 4(p<0.0005), while group 3 exhibited less leakage than group 2(p<0.01) and group 4(p<0.0005). 3. At the occlusal margins, group 4 showed less leakage than group 3(p<0.1) and group 1(p<0.005), while group 3 exhibited less leakage than group 2(p>0.1) and group 1(p<0.025).

• Transactions on Electrical and Electronic Materials
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• v.2 no.4
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• pp.19-23
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• 2001

In this paper, design considerations and manufacturing procedure of 200 class insulation system with polyimide(Kapton) main insulation and silicone resin VPI process on the traction motor thor EMU will be reviewed. The performance test and the long life evaluation test that prove stability and reliability of Insulation system for traction motor will also be introduced.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.121-132
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• 1991

The purpose of the study was to evaluate the marginal sealing effect of composite resin inlays according to the luting techniques and compare them to the conventional direct resin filling technique. 90 cavities of class V were prepared on the buccal surface of 90 extracted molar teeth, which were divided into four groups. Cavities of control group were directly filled with Scotchbond 2 and P - 50, and those of composite resin inlay groups were luted with one of the followings: Adhesive bond followed by Adhesive cement, All bond followed by Adhesive cement, Fuji - ionomer type L All the specimens were immersed in India ink dye solution for 7 days at $37^{\circ}C$ incubator after thermocycling between $5^{\circ}C$ and $60^{\circ}C$ and longitudinally sectioned with diamond disk inot two parts All the specimens were observed at the occlusal and gingival margins and statistical analysis was performed. The results were as follows: 1. Groups filled with composite resin inlay showed less marginal leakage than the group directly filled(p<0.01). 2. There was no significant difference in marginal leakage between composite resin inlay groups luted with Adhesive bond followed by Adhesive cement and the group luted with All bond followed by Adhesive cement(p>0.05). 3. At occlusal margins, Composite resin inlay group luted with Adhesive bond followed by Adhesive cement showed less marginal leakage than the group luted with Fuii ionomer type I(p<0.01). At gingival margins, composite resin inlay group luted with All bond followed by Adhesive cement showed less marignal leakage than the group luted with Fuji ionomer type I(P<0.01).

• 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.12 no.1
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• pp.107-116
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• 1986

The primary aim of this study was to assess the effects of the margin designs and composite resins on the marginal leakage of Class V resin restorations. 60 Class V cavities with $90^{\circ}$ butt joint, 60 with $45^{\circ}$ bevel joint, and 60 with concave joint were prepared on the labial surfaces of 38 extracted anterior teeth and the buccal and lingual surfaces of 71 premolars, and classified as the butt group, bevel group and concave group, respectively. After completion of the cavity preparation, Heliosit${(R)}$ was filled in 20 butt joint cavities, 20 bevel joint cavities, and 20 concave cavities. And Hi-Pol$^{(R)}$ and Palfique$^{(R)}$ were filled in the same manner, respectively. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$, $37^{\circ}C$, and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours, and buccolingually sectioned with sectioning machine. The sectioned specimens were examined under the light microscope. The results indicated the following: 1. The bevel group showed the least amount of marginal leakage compared with the other two design groups, but the statistical analysis showed no significant difference at the 95% confidence level. 2. Hi-Pol$^{(R)}$ group showed the most severe marginal leakage compared with the other composite resin materials, but there was no significant difference in the groups. 3. The bevel-Heliosit$^{(R)}$ subgroup, which was filled with Heliosit$^{(R)}$ in the beveled cavities, showed the least amount of marginal leakage, but there was no significance in all the subgroups.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.97-105
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• 1990

When conventional root canal treatment is failed or contraindicated, retrograde root canal filling following apicoectomy is a valuable procedure, aimed at hermetically sealing the root canal against leakage of irritants from the canal into the periapical tissue. In this in vitro investigation, to analyze apical microleakage electrochemically in teeth with different retrograde filling materials and preparation types, single - rooted tooth was cut 2mm from the apex and each Class I and Slot preparation was prepared. Experimental groups : Group 1. Amalgam filling with cavity varnish in Class I preparation Group 2. Scotchbond 2+Silux filling in Class I preparation Group 3. Gutta percha filling with ZOE cement in Class I preparation Group 4. Amalgam filling with cavity varnish in Slot preparation Group 5. Scotchbond 2+Silux filling in Slot preparation Each specimens was immersed in 1% solution of KCl, and applied a potential of 9V external power supply. Measurements of the current flow were obtained at 1, 2, 3, 7, 9, 12, 14, 18, 21, 25 and 28 day after immerson. Marginal microleakage were compared and evaluated. The results were as follows ; 1. The group filled with composite resin with dentin bonding agent shows lower apical microleakage value than the group filled with amalgam following varnish application (P<0.01). 2. In the group filled with gutta percha, apical microleakage value was the hightest 3. There was no significant difference between Class I cavity and Slot type cavity regardless of the used materials.

• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.639-646
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• 1998

To evaluate the effect of interface conditions and retention grooves in the Class V composite resin restoration of the maxillary first premolar, the distribution of the values of stress and displacement was analyzed with the two-dimensional finite element method. The results were obtained as follows : 1. Boundary elements and Stiffness values could be used as the interface parameters in the, finite element method. 2. The amount of restriction of the displacement at the cervical margin by placing a retention groove at the cervical wall was about three times as high as that by placing a retention groove at the occlusal wall. 3. Because of the relative amount of tensile components of the stress values in the bucco-lingual direction, the possibility of dislocation of the restoration was much higher at the cervical margin than at the occlusal margin. 4. It might be recommended that both occlusal and cervical retention grooves be used routinely, but if one, it be placed at the cervical wall.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.346-355
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• 1999

To evaluate the micro leakage of compomer, 4 materials were divided into 4 groups of 15 cavities each.(Group 1: Z-100, Group 2: Dyarct AP, Group 3: Fuji II LC, Group 4: Compoglass) After the class II cavities were prepared using carbide bur No. 553, all specimen were restored by incremental filling technique. In group 3, Z-100 was filled with a base of a light curing glass-ionomer. After 7 days, all specimens were thermocycled between $5^{\circ}C$ and $55^{\circ}C$ for 500 cycles, followed by placement in 50% silver nitrate dye for 2 hours at $37^{\circ}C$. After rinsed in distilled water, these teeth were immersed in photodeveloping solution and exposed to fluorescent light for 6 hours. Teeth were then washed in distilled water to remove the photodeveloping solution, sectioned mesio-distally and evaluated. The results were as follows : 1. In the cervical portion, there was significant difference between Fuji II LC and other groups(Z-100, Dyract AP, Compoglass), Fuji II LC had the least value.(p<0.05) 2. In the cervical portion, there was not significant difference among Dyract AP, Z-100 and Compoglass. 3. In the occlusal portion, there was not significant difference among Dyract AP, Z-100 and Compoglass. From the results above, In enamel, microleakage of compomer such as Dyract AP and Compoglass resemble to that of composite resin. It is thought that it is due to characteristics of composite resin portion of compomer. But in dentin, microleakage of compomer is higher than that of resin modified glass ionomer cement, it is thought that in compomer, acid-base reaction is not developed with dentin.