• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.791-799
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• 1996

The purpose of this study was to compare the shear bond strength of adhesion bridge by various resin cements. One hundred and foully 1st premolars were used. The teeth were cut below 2mm from CEJ and the coronal portions were used. The coronal portions were embeded with the acrylic resin and trimmed with sic paper until the flat plane with ${\phi}$ 4mm above acrylic resin sticks in height 5mm were casted with nonprecious metal and the using surfaces were treated with sic paper from #200 to #1200 and polished with alminum oxide paste. And then, the using surfaces were sandblasted and treated with the electrochemical etching. The teeth were divided into three groups of fourty two each. In group I, teeth and specimens were cemented with Panavia 21 In group II, teeth and specimens were cemented with Superbond In group I, teeth and specimens were cemented with All-Bond & composite resin cement Each group was subdivided into three subgroups according to the storage period ; one-day storage, fifteen-day storage, and thirty-day storage. The special jig was made. Then, the specimen and jig were mounted to Instron Universal Testing Machine and the failure were measured. The results were as follows. 1. There was statisfically significant difference between the failure loads of group I and group II and III after one day storage(P<0.01), 2. There was statisfically significant difference between the failure loads of group II and group I and III and between group I and group III at fifteen day storage(P<0.01). 3. There was statisfically significant difference between the failure loads of group I and II and group III after thirty day storage(P<0.01). 4. There was statisfically significant difference between the failure loads of one day storage and fifteen and thirty days storages in group III (P<0.01).

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.217-225
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• 2002

When we use the flowable resin on the primary molars for quick handling, one of the most important property is the wear resistance. This study was performed to compare the wear resistance characteristics of four flowable composite resins [Arabesk flow (group 1), Tetric flow (group 2), Aeliteflow (group 3), Filtek flow (group 4)] to that of one control composite resin [Z100 (group 5)]. Specimen discs(n=10), 10mm wide and 2mm thick, were stored in distilled water at $37^{\circ}C$ for 7 days prior to testing. The specimens were subjected to 50,000 strokes at 2 Hz on the MTS system. During the test, the following parameters were maintained: the lateral excursion at 0.4mm, occlusal force at 2-100N with a force profile in the form of a half sine wave. The measurements of volume loss, depth of wear, and Vicker's hardness number of composite resins, and SEM observations of the polished and abraded surfaces were established. One-way ANOVA and Scheffe's multiple comparison test were employed to detect statistically significant differences among the flowable composite resin groups and the control composite group at P<.05. The following results were obtained: 1. Group 3 showed the least volume loss, while group 4 showed the greatest. The mean volume loss increased in the following order: group 3

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.223-233
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• 1995

The purpose of this study was to evaluate the effects of surface conditioning with $10\%$ polyacrylic acid, etching with $38\%$ phosphoric acid, and polishing with a slurry of pumice on shear bond strengths of light-cured glass ionomer cement, chemically cured glass ionomer cement, and a composite resin to enamel, and to observe the failure patterns of bracket bondings. Shear bond strengths of glass ionomer cements were compared with that of a composite resin. Metal brackets were bonded on the extracted human bicuspids after enamel surface treatments, and samples were immersed in the $37^{\circ}C$ distilled water bath, and shear bond strengths of glass ionomer cements and a composite resin were measured on the Instron machine after 24hrs passed, and the deboned samples were measured in respect of adhesive remnant index. Scanning electron micrographs were taken of enamel surfaces after various treatments. The data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. 1. Shear bond strength of light-cured glass ionomer cement showed statistically higher than that of chemically cured glass ionomer cement. 2. Shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel treated with $10\%$ polyacrylic acid and $38\%$ phosphoric acid showed statistically higher than those with a slurry of pumice. 3. According to scanning electron micrographs, enamel surface conditioned with $10\%$ polyacrylic acid is slightly etched and cleaned, that etched with $38\%$ phosphoric acid is severely etched, and that polished with a slurry of pumice is irregulary scretched and not completely cleaned. 4. After debonding, light-cured glass ionomer cement to enamel treated with $10\%$ polyacrylic acid showed less residual materials on the enamel solace than composite resin to enamel etched with $38\%$ phosphoric acid. 5. There was no significant difference in the shear bond strength of light-cured glass ionomer cement to enamel treated with $10\%$ polyacrylic acid and that of composite resin to enamel etched with $38\%$ Phosphoric acid.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.66-78
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• 2004

The objective of this study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration in enamel and dentin achieved with those gained using the conventional technique and vibration technique. For enamel specimens, thirty teeth were sectioned mesio-distally. Sectioned two parts were assigned to same adhesive system but different treatment(vibration vs. non-vibration). Each specimen was embedded in 1-inch inner diameter PVC pipe with a acrylic resin. The buccal and lingual surfaces were placed so that the tooth and the embedding medium were at the same level. The samples were subsequently polished silicon carbide abrasive papers. Each adhesive system was applied according to its manufacture's instruction. Vibration groups were additionally vibrated for 15 seconds before curing. For dentin specimen, except removing the coronal part and placing occlusal surface at the mold level, the remaining procedures were same as enamel specimen. Resin composite(Z250. 3M. U.S.A.) was condensed on to the prepared surface in two increments using a mold kit(Ultradent Inc., U.S.A.). Each increments was light cured for 40 seconds. After 24 hours in tap water at room temperature, the specimens were thermocycled for 1000cycles. Shear bond strengths were measured with a universal testing machine(Instron 4465, England). To investigate infiltration patterns of adhesive materials, the surface of specimens was examined with scanning electron microscope. The results were as follows: 1. In enamel the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration group(group 1, 3, 5). The differences were statistically significant except AQ bond group. 2. In dentin, the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration groups(group 1, 3, 5). But the differences were not statistically significant except One-Up Bond F group. 3. The vibration group showed more mineral loss in enamel and longer resin tag and greater number of lateral branches in dentin under SEM examination.

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.174-187
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• 2000

The Quaternary coarse-grained sandy sediments are distributed along the channels of Seomjin River. The fluvial sediments were sedimentologically studied in horizontal and vertical distributions. To analyze depositional environments and facies changes in the sediments, sediment sampling from river mouth to upper stream and desctriptive approaches to the sediment profiles outcropped near Kurye were carried out. The sediments along the stream lines of the river are assigned to very coarse to coarse sand in grain size. The sediment grains are widely scattered in sorting and moderately sorted in average. For skewness and kurtosis, the sediments ranges from very fine to very coarse skewed and from very lepto-kurtic to extremelyl epto-kurtic states, respectively. The sediments are divided into slightly gravelly sand, gravelly sand and sandy gravel in sediment type. The pain shape in the sandy sediments are dominant in equant and tabular forms showing wide varieties. The sandy sediments are mostly poorly sorted and are highly variable in surface texture with SEM. Some smaller grains in the sediments ordinarily show polished surfaces. Of those grains, quartz ones are commonly angular to surounded. On the basis of facies changes and sedimentary structures, outcropped fluvial sediment profiles in Kurye are classified into xGyS, mGyS, gGyS, xSM, xS, mS, mGyM, IgM in facies. These eight facies are reformed as facies assemblage I and ll. The facies assemblage I and II are interpreted as the products of the channel deposits in braided stream and flood plain ones besides channels, respectively. The change facies assemblage I with facies assemblage ll imply that depositional environments hadbeen migrated from braied sream to flood plain ones.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.632-640
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• 2002

The objective of the study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration into dentinal tubules achieved with those gained using the conventional technique. Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel and were embedded in 1-inch PVC pipe with acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form one flat surface, and the samples were subsequently polished with silicon carbide abrasive papers. The samples were randomly assigned to 4 groups(n=22). On Group 1 and 2, Single Bond(3M-ESPE, St. Paul, USA) was used, and on Group 3 and 4, One-Step(Bisco Inc., Schaumburg, USA) was used, and each was applied according to its manufacturer's instructions. For Group 2 and Group 4, vibration was applied with ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. Resin composite was condensed on to the prepared surface in two increments using a mold kit(Ultradent Products Inc., USA) and each was light-cured for 40 seconds. After 24 hours in tap water at room temperature the specimens were thermocycled, and shear bond strengths were measured with a universal testing machine(Instron 4465, Canton, USA). To investigate infiltration patterns of the adhesive materials, the surface of specimen was examined with scanning electron microscope. The results were as follows. 1. The shear bond strengths of vibration groups(Group 2, Group 4) were significantly greater than those of the non-vibration groups(Group 1, Group 3)(p<0.05). 2. The shear bond strengths of Single Bond and One-Step were not significantly different (p>0.05). 3. The vibration groups showed greater number of resin tags in tubules and lateral branches under SEM.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.343-355
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• 1985

Spectral reflectivity and microhardness were measured quantitatively on polished surfaces of a selection of bireflecting minerals obtained from several well known metallic deposits. Incremental errors are much higher than decremental errors and errors were found to be lowest in the spectral region close to the green wavelength ($544m{\mu}$). The characteristics of the spectral profile are significant in their control of white light color. The covellite and graphite have reflectivity profiles similar in shape for each principal direction, showing noticeable difference in magnitude between the profiles: The spectral reflectivity of covellite parallel to the extraordinary vibration is higher (R$$\simeq_-$$10%) than that parallel to the ordinary vibration and graphite shows opposite feature. Reflectivity of the enargite and famatinite cut parallel to the cleavage plane is always higher (R$$\simeq_-$$5%) than that of the section cut normal. The optical symmetry of 5 bireflecting minerals was determined by noting the variation in reflectivity at $544m{\mu}$. The data indicate that covellite is optically uniaxial positive and graphite is optically uniaxial negative. The Rm values for enargite and famatinite are clearly closer to the minimum value for the mineral ($R_1$) than to the maximum value ($R_2$) : the minerals can be recognized as optically biaxial positive. Enargite and famatinite cut parallel to cleavage have much higher hardness values (HV=> $200kg/mm^2$) than those cut normal to cleavage. Vickers indentations exhibit characteristic features for all the bireflecting mineral species studied. Broad radicle groupings of the mineral species can be made with regard to the reflectivity microhardness numbers.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.352-368
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• 2008

This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal. Canada) for dentistry. Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another. Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth. And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE $L^*a^*b^*$values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan. There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third. Color difference (${\Delta}E^*$) among the Shade map which analyzed as same shade by ShadeScan were above 3. Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.195-203
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• 2023

Purpose: This study aimed to evaluate the influence of surface sealants on the surface roughness of composite resins. Materials and Methods: The study used microfilled composite resin (Metafil CX, Sun Medical Co.) and hybrid composite resin (Aelite^TM LS posterior, Bisco). Sixty specimens (8 mm in diameter and 4 mm in height) of each composite resin type were prepared and divided into 3 groups. Each specimen was ground with 600, 1000, and 2000-grit sandpaper. The Surface roughness (Ra) values were measured using a surface roughness tester (SJ-301, Mytutoyo) before and after surface sealant application. Surface sealants, BisCover^TM LV (Bisco), Optiguard^® (Kerr), and Seal-n-Shine^TM (Pulpdent), were applied to the specimens, as instructed and observed by scanning electron microscope (JSM-7500, JEOL) and atomic force microscope (MultiMode IV, Veeco Instruments). Results: Specimens ground with 600-grit sandpaper coated with surface sealants exhibited significantly lower Ra values than the untreated group (P < 0.05). Specimens ground with 1000 and 2000-grit sandpaper showed statistically no difference. There was no significant difference in surface roughness among BisCover^TM LV, Optiguard^®, and Seal-n-Shine^TM. SEM and AFM revealed remarkably decreased microdefects on the surfaces of composite resins after surface sealant application. Conclusion: Surface sealants can influence surface roughness when applied on the rough surface of composite resins but not on highly polished composite resins.