• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.180-190
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• 2007

The purpose of this study was to evaluate the abrasion resistance of surface penetrating sealant which was applied on a composite resin restoration and to provide proper time to reapply sealant on composite resin surface. Two hundred rectangular specimens, sized $8\times3\times2mm$, were made of Micronew (Bisco, Inc., Schaumburg, IL, U.S.A) and divided into two groups; F group (n = 10) was finished with coarse and medium grit of Sof-Lex discs and BisCoverwas applied B group (n = 190) after finishing with discs. B group was again subdivided into nineteen subgroups From B-1 group to B-18 group were subjected to toothbrush abrasion test using a distilled water-dentifrice slurry and toothbrush heads B-IM group was not subjected to toothbrush abrasion test. Average surface roughness (Ra) of each group was calculated using a surface roughness tester (Surfcorder MSE-1700: Kosaka Laboratory Ltd., Tokyo, Japan) . A representative specimen of each group was examined by FE-SEM (S-4700: Hitachi High Technologies Co., Tokyo, Japan). The data were analysed using cluster analysis, paired t-test, and repeated measure ANOVA. The results of this study were as follows; 1. Ra off group was $0.898{\pm}0.145{\mu}m$ and B-IM group was $0.289{\pm}0.142{\mu}m$. Ra became higher from B-1 group $(0.299{\pm}0.48{\mu}m$ to B-18 group $(0.642{\pm}0.313{\mu}m$. 2. Final cluster center of Ra was $0.361{\mu}m$ in cluster 1 $(B-IM\simB-7)$, $0.511{\mu}m$ in cluster 2 $(B-8\simB-14)$ and $0.624{\mu}m$ in cluster 3 ($(B-15\simB-18)$. There were significant difference among Ra of three clusters. 3 Ra of B-IM group was decreased 210.72% than Ra of F group. Ra of B-8 group and B-15 group was increased 35.49% and 51.35% respectively than Ra of B-IM group. 4. On FE-SEM, B-IM group showed the smoothest resin surface. B-8 group and B-15 group showed vertically shallow scratches , and wide and irregular vertical scratches on composite resin surface respectively. Within a limitation of this study, finished resin surface will be again smooth and glazy if BisCover would be reapplied within 8 to 14 months after applying to resin surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.440-447
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• 2009

This study was performed to compare the wear resistance of sealant and flowable resins for analyzing the effect of flowable resin as a sealant in preventive resin restorations. Specimens were made and Vicker's hardness number and surface roughness were measured. SEM observations of the polished and abraded surfaces were established. Kruskal-Wallis rank test and Mann-Whitney U test at the significant level of ${\alpha}$=0.05 were used. The following results were obtained: 1. The microhardness was decreased among groups in following order: Z350 (3M ESPE, U.S.A), Estelite (Tokuyama Dental, Japan) and Ultraseal (Ultradent, U.S.A). There were significant differences in all groups (p<0.0001). 2. The surface roughness was decreased among groups in following order: Ultraseal XT plus, Palfique Estelite LV and Filtek Z350 flowable. However, there is no statistically significant differences in roughness among Estellite, Z350 and Ultraseal at the significance level of ${\alpha}$=0.05, with p=0.116 3. SEM observation of the unworn and worn surfaces revealed the qualitative differences in the wear appearance among groups. The results in this study indicate that flowable resin is better than sealant in aspect of physical properties.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.418-426
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• 2008

The objectives of this study were to examine the properties of fluoride-releasing resin composite restorative materials. Four commercially available compomer materials (Compoglass F: CF, $Dyract^{(R)}$ AP: DA, $Dyract^{(R)}$ flow: DF, F2000: FT) and one fluoride-releasing composite resin ($Tetric^{(R)}$ Ceram: TC) were selected as experimental materials. Rectangular-shaped tensile test specimens were fabricated in a teflon mold giving 5mm in gauge length and 2mm in thickness. Disk-shaped specimens were fabricated in the split teflon mold with diameter of 15mm and thickness of 1mm. After curing for an hour, specimens were immersed in deionized water at $37^{\circ}C{\pm}1^{\circ}C$ for 30 days. All specimens were thermocycled for 10,000 cycles with 15 seconds of dwelling time in each $5^{\circ}C$ and $55^{\circ}C$ water baths. Toothbrush abrasion test was conducted under a load of 1.5 N and the abraded surfaces were examined with surface roughness tester (SV-3000, Mitutoyo Co, Japan) and SEM (JSM-5800, JEOL, Japan). Fluoride recharging was done by toothbrushing for 3 min. using a fluoride toothpaste (Perio Alpine Herb, LG Household & Health Care, Korea). The results obtained were summarized as follows; 1. The highest tensile strength value of 32.3 MPa was observed in TC group and the lowest value of 16.8 MPa was observed in CF group. The tensile strength of TC group was significantly higher than those of CF and DF groups (P<0.05). 2. The lowest Ra value of 0.287 was observed in TC group and the highest value of 1.516 was observed in FT group. The Ra value of FT group was significantly higher than other groups (P<0.05). 3. The abraded surfaces revealed the increase of surface roughness due to the protrusion and missing of filler particles. 4. The release of fluoride of compomers after tooth brushing by Perio Alpine Herb was initially large and then followed by small and continuously. But it remains small and constant in fluoride-releasing composite resin of TC. 5. The highest value of fluoride release after toothbrushing by Perio Alpine Herb was $2.064{\mu}g/cm^2$ in CF group and the lowest value was $0.1119{\mu}g/cm^2$ in TC group. The amount of fluoride release of CF group was significantly higher than other groups (P<0.05).