• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.559-568
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• 1996

The purpose of this study was to evaluate the micro leakage of composite resin when various phosphoric acid agents were used to etch the enamel and dentin. In this study, class V cavities were prepared on the buccal surfaces of fourty extracted human molar teeth, and they were randomly assigned into 4 groups with 10 teeth. The cavities of each groups were etched with 10%, 32%, 35% and 37% phosphoric acids for 15 seconds, washed and dried and the cavities were restored with composite resin after application of the adhesive. The specimens were immersed in 2% methylene blue solution for 3 days. And then, the specimens were sectioned buccoligually. Degree of dye penetration at tooth-restoration interfaces was examined by Inverted Metallurgical Microscope at the occlusal and gingival margins. The result were as follows : 1. The degree of microleakage at occlusal and gingival margin in all group was statistically difference among 10% and 35% (P<0.01), 10% and 37% (P<0.01), 32% and 35% (P<0.05) and 32% and 37% (P<0.05) acid concentrations, but was not statistically difference between 10% and 32%, 35% and 37% acid concentrations (P>0.05). The degree of microleakage was showed to dimish with increase of acid concentration. 2. The degree of microleakage at the occlusal margin was statistically significant difference among 10% and 32%,10% and 35%, 10% and 37% acid concentrations(P<0.05). The degree of microleakage among 32% and 35%, 32% and 37% and 32% and 37% acid concentrations was not statistically significant difference. 3. In comparison of microleakage at the gingival margin, the degree of microleakage above 32% acid concentration was not showed less than 10% acid concentration (P>0.05). In comparison of 32%, 35%, 37% acid concentrations, the degree of microleakage at 35% and 37% acid concentrations was showed less than 32% acid concentration(P<0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.81-87
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• 2019

Patients with Down's syndrome have several dental complications such as small teeth caused by underdevelopment of dentin and enamel, periodontitis, agenesis of teeth, prolonged retention of primary teeth and malocclusion due to narrow palate. Removable denture with maxillary double crowns would be a good treatment option to solve the problems of the patient with Down's syndrome. Double crowns compensate the insufficient support and retention of denture and easily solve the cross bite problem. Double crowns also allow easy repair of denture in case of abutment teeth extraction. In this case, 26-year-old female patient with Down's syndrome and dental phobia had small number of teeth with enamel hypoplasia, prolonged retention of primary teeth and dental cross bite. Prosthetic treatment was done using removable denture with double crowns in the maxilla. In the mandible, teeth preparation was done on enamel margin without anesthesia. Anterior laminate and posterior complete zirconia crown restorations were performed. As a result, the cross bite was effectively corrected by denture with double crowns. Pronunciation and appearance were also improved without extraction of teeth and dental anesthesia.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.282-289
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• 2006

The purpose of this study was to compare the ability of three resin surface sealants to prevent microleakage in Class V composite resin restorations. Forty Class V cavities with the occlusal margin in enamel and gingival margin in dentin were prepared on the buccal surfaces of sound extracted molars, and restored with composite resin. Restorations were randomly assigned into one of four equal groups (n = 10): a control group, without resin sealing, and three experimental groups in which margins were sealed with Fortify Plus, Biscover and Permaseal, respectively. Specimens were thermocycled, immersed in a 2% methylene blue solution for 4 hours, sectioned longitudinally, and observed the leakage at the occlusal and gingival margins. The result was analyzed using Kruskal-Wallis test, Mann-Whitney test and Wilcoxon signed rank test. In conclusion, the ability to reduce microleakage at occlusal margins was similar in all of three sealants. However at gingival margin, it depended on the type of used resin surface sealant. At gingival margin. control and Fortify Plus group showed statistically higher microleakage than PermaSeal group. and Fortify Plus group also showed higher microleakage than BisCover group (p < 0.05).

• Restorative Dentistry and Endodontics
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• v.27 no.1
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• pp.34-43
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• 2002

The purpose of this study was to compare microleakage and marginal hybrid layer in class V restorations using two one-bottle adhesives and one self-etching adhesive. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were pre-pared on buccal and lingual surfaces of 30 extracted human molar teeth. Prepared teeth were randomly divided into three treatment groups (n=30) and restored with three adhesives and composites: Single Bond/Filtek Z-250 (Group 1), Prime&BondNT/Esthet.X (Group 2), UniFil Bond/UniFil F (Group 3). For microleakage, samples were stored in room temperature water for 24 hours, thermocycled stained with 2% methylene blue dye, sectioned into halves, scored and analysed using Mann-whitney test and Wilcoxon signed rank sum test. For marginal hybrid layer, samples were sectioned into halves, treated with 10% phosphoric acid for 5 seconds, stored in 5% NaOCL solution for 24 hours, dried and gold coated. Occlusal and gingival margins of each sample were inspected under SEM. The results of this study were as follows ; 1. Microleakage at the occlusal margins was not evident in group 1 and group 2, but it showed in group 3 (p<0.05). 2. Microleakage in group 1 and group 3 was significantly lower than in group 2 at gingival margins (p<0.05). 3. Microleakage at gingival margins was greater than at occlusal margins in group 1 and group 2, but microleakage at occlusal margins was greater than at gingival margins in group 3 (p<0.05). 4. In group 1 and group 2, no gaps at occlusal margins showed. But gaps showed in group 3. Occlusal margins were free from a hybrid layer in all groups 5. The thickness of the marginal hybrid layers was 2.5~5 $\mu\textrm{m}$ thick in group 5 $\mu\textrm{m}$ thick in group 2 and 1.5 $\mu\textrm{m}$ thick in group 3. 6 There was no corelation between microleakage and thickness of marginal hybrid layer. In coclusion, the effect of dentin adhesives on microleakge in class V composite restorations was excellent when one-bottle adhesives were applied on enamel margin, and it was good when a self-etching adhesive was applied on dentinal margin. There was no corelation between microleakage and thickness of marginal hybrid layer.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.477-483
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• 2009

The purpose of this study was to compare the microleakage of low and high viscosity flowable resins in class V cavities applied with 1-step adhesives. Forty Class V cavities were prepared on the cervices of buccal and lingual surfaces of extracted molar teeth and divided into four groups (n=8). Cavities were restored with AQ Bond Plus /Metafil Flo $\alpha$, G-Bond/ UniFil LoFlo Plus (Low flow groups), AQ Bond Plus/Metafil Flo and G-Bond/UniFil Flow (High flow group), respectively. Specimens were immersed in a 2% methylene blue solution for 24 hours, and bisected longitudinally. They were observed microleakages at the enamel and dentinal margins. In conclusion, the low viscosity flowable resins showed lower marginal microleakage than do the high vis cosity flowable resins in class V cavities.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.158-174
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• 2002

The aim of this study was to investigate the effect of light irradiation modes on polymerization shrinkage, degree of cure and microleakage of a composite resin. VIP$^{TM}$ (Bisco Dental Products, Schaumburg, IL, USA) and Optilux 501$^{TM}$ (Demetron/Kerr, Danbury, CT, USA) were used for curing Filtek$^{TM}$ Z-250 (3M Dental Products, St. Paul., MN, USA) composite resin using following irradiation modes: VIP$^{TM}$ (Bisco) 200mW/$\textrm{cm}^2$ (V2), 400mW/$\textrm{cm}^2$ (V4), 600mW/$\textrm{cm}^2$ (V6), Pulse-delay (200 mW/$\textrm{cm}^2$ 3 seconds, 5 minutes wait, 600mW/$\textrm{cm}^2$ 30seconds, VPD) and Optilux 501$^{TM}$ (Demetron/Kerr) C-mode (OC), R-mode (OR). Linear polymerization shrinkage of the composite specimens were measured using Linometer (R&B, Daejeon, Korea) for 90 seconds for V2, V4, V6, OC, OR groups and for up to 363 seconds for VPD group (n=10, each). Degree of conversion was measured using FTIR spectrometer (IFS 120 HR, Bruker Karlsruhe, Germany) at the bottom surface of 2 mm thick composite specimens V2, Y4, V6, OC groups were measured separately at five irradiation times (5, 10, 20, 40, 60 seconds) and OR, VPD groups were measured in the above mentioned irradiation modes (n=5 each). Microhardness was measured using Digital microhardness tester (FM7, Future-Tech Co., Tokyo, Japan) at the top and bottom surfaces of 2mm thick composite specimens after exposure to the same irradiation modes as the test of degree of conversion(n=3, each). For the microleakage test, class V cavities were prepared on the distal surface of the ninety extracted human third molars. The cavities were restored with one of the following irradiation modes : V2/60 seconds, V4/40 seconds, V6/30 seconds, VPD , OC and OR. Microleakage was assessed by dye penetration along enamel and dentin margins of cavities. Mean polymerization shrinkage, mean degree of conversion and mean microhardness values for all groups at each time were analyzed using one-way ANOVA and Duncan's multiple range test, and using chi-square test far microleakage values. The results were as follows : . Polymerization shrinkage was increased with higher light intensity in groups using VIP$^{TM}$ (Bisco) : the highest with 600mW/$\textrm{cm}^2$, followed by Pulse-delay, 400mW/$\textrm{cm}^2$ and 200mW/$\textrm{cm}^2$ groups, The degree of polymerization shrinkage was higher with Continuous mode than with Ramp mode in groups using Optilux 501$^{TM}$ (Demetron/Kerr). . Degree of conversion and microhardness values were higher with higher light intensity. The final degree of conversion was in the range of 44.7 to 54.98% and the final microhardness value in the range of 34.10 to 56.30. . Microleakage was greater in dentin margin than in enamel margin. Higher light intensity showed more microleakage in dentin margin in groups using VIP$^{TM}$ (Bisco). The microleakage was the lowest with Continuous mode in enamel margin and with Ramp mode in dentin margin when Optilux 501$^{TM}$ (Demetron/Kerr) was used.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.202-210
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• 2014

Purpose: The aim of this study was to evaluate the stress concentration and distribution whether restoring the cavity or not while restoring with metal ceramic crown on tooth with abfraction lesion using finite element analysis. Materials and methods: Maxillary first premolar was selected and made a total of 10 finite element model. Model 1 was natural tooth; Model 2 was tooth with metal ceramic crown restoration which margin was positioned above 2 mm from CEJ; Model 3 was tooth with metal ceramic crown restoration which margin was positioned on CEJ; Model 4 was natural tooth which has abfraction lesion; Model 5 and 6 had abfraction lesion and the other condition was same as model 2 and 3, respectively; Model 7 was natural tooth which had abfraction lesion restored with composite resin; Model 8 and 9 was tooth with metal ceramic crown after restoring on abfraction lesion with composite resin; Model 10 was restored tooth on abfraction lesion with composite resin and metal ceramic crown restoration which margin is positioned on lower border of abfraction lesion. Load A and Load B was also designed. Von Mises value was evaluated on each point. Results: Under load A or load B, on tooth with abfraction lesion, stress was concentrated on the apex of lesion. Under load A or load B, on tooth that abfraction lesion was restored with composite resin, the stress value was reduced on the apex. Conclusion: In case of abfraction lesion was restored with composite resin, the stress was concentrated on the apical border of restored cavity regardless of marginal position. It was favorable to place crown margin on the enamel for restoring with metal ceramic crown.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.355-362
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• 2005

The purpose of this study was to compare the effect on marginal leakage of a resin surface sealant (Biscover) applied before or after polymerization of composite resin to unsealed composite restorations. Thirty Class V cavities with the occlusal margin in enamel and cervical margin in dentin or cementum were prepared on the buccal surfaces of sound extracted molars and restored with a microfilled light-cured composite resin (Micronew). Restorations were randomly assigned into one of three equal groups (n = 10): a control group - no surface sealing, group 1 - applied Biscover after polymerization of the composite resin. and group 2 - applied Biscover before polymerization of the composite resin. Specimens were thermocycled, immersed in a $20\%$ methylene blue solution for 4 hoots, sectioned longitudinally, and analyzed for leakage at the occlusal and gingival margins. The results of this study were as follows 1. In sealed group, group 2 showed higher microleakage than group 1 at both occlusal and gingival margins. but there was no significant difference between two groups (p > 0.05). 2. Unsealed control group showed a little higher microleakage than sealed group at occlusal margins, and a little Higher or similar microleakage than sealed group at gingival margins (p > 0.05) 3. Control group and group 2 showed significantly less microleakage at the occlusal margins, but group 1 showed no significantly difference between microleakage at the occlusal and gingival margins.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.148-158
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• 1994

The purpose of this study was to compare the adaptation to tooth structure of light - cured glass ionomer cement with that of self -cured glass ionomer cement. In this study, class V cavities were prepared on the buccal surfaces of 10 extracted human premolar teeth, and teeth were randomly assigned 2 groups of 5 teeth each. The cavities of self-curing glass ionomer cement group were restored with the Fuji n. and the cavities of lightcuring glass ionomer cement group were restored with the Fuji II LC. The surfaces of glass ionomer cements were applied with All-Bond 2 adhesive, and cured with visible light. The restored teeth were stored in 100% relative humidity at $37^{\circ}C$ for 24 hours. And then. the roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned occlusogingivally through the center of glass ionomer restorations. Adaptation at tooth-restoration interface was assessed occlusally. axially, and gingivally by scanning electron microscope. The results were as follows : 1. On the occlusal margin, the group of self - curing glass ionomer cement showed closer adaptation to both enamel and dentin than the group of light-curing glass ionomer cement showing 5/lm gap between cement and tooth structure. 2. On the axial wall. the group of light-curing glass ionomer cement showing 5-$7{\mu}m$ gap between cement and dentin showed closer adaptation to dentin than the group of self -curing glass ionomer cement showing 10-$15{\mu}m$ gap between cement and dentin. 3. On the gingival margin, the group of light-curing glass ionomer cement showing 2-$5{\mu}m$ gap between cement and dentin(X 1200) showed closer adaptation to dentin than the group of self-curing glass ionomer cement showing 20pm gap between cement and dentin(X 600). 4. The group of self -curing glass ionomer cement showed closer adaptation on the occlusal margin than on the gingival margin, and the group of light-curing glass ionomer cement showed similar adaptation on both occlusal and gingival margins.

• 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).