• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.522-529
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• 2001

This study seeks to know the effect of fluoride topical application on the shear bond strength between enamel and fissure sealant. On group 1,2,3,4, Teethmate A(unfilled sealant) and on group 5,6,7,8 Ultraseal XT(filled sealant) were used. Group 1 and 5 were not pre-treated with fluoride and group 2 and 6 were pre-treated with 1.23% APF for 4minutes. Group 3 and 7 were pretreated with 2.0% NaF for 4 minutes. and group 4 and 8 were pumiced with abrasive containing fluoride for 10 seconds. Prepared specimens were acid etched for 30 seconds using 35% phosphoric acid, and then sealant was cured to the specimen using a 3mm diameter by 2mm height mold. They went through thermocycling. Its shear bond strength was measured, and then acid etched both groups that were pretreated with fluoride and that were not pretreated with fluoride. Then we examined the surface of the specimen with EM and came up with these results. In groups using unfilled sealant(group 1,2,3.4) there were no significant differences between oops pretreated with fluoride and groups not pretreated with fluoride. In groups using filled sealant(group 5,6,7,8), groups 6 and 7(treated with 1.23% APF 2.0% NaF respectively) showed significantly lower shear bond strength, compared to group 5 (not pretreated with fluoride) and group 8 (pumiced with abrasive containing fluoride) (p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.761-771
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• 1998

In this study, attempt has been made to evaluate the effect of $CO_2$ laser irradiation on enamel surface structure and the bond strength of sealant material. Conventional acid etching was used as a control technic for comparison. The results obtained from this experiment were as follows; 1. The highest mean shear bond strength value was observed in samples of Group I (acid-etching) with the statistical significance(p<.05) between all the other groups. 2. The shear bond strength in Group IV was the lowest among laser etching groups. but there were no significant difference between them(p>.05). 3. Scanning electron microscopic observation showed that the rough and irregular surface was created by $CO_2$ laser treatment with the formation of numerous pores, micro-cracks, and small bubble-like inclusion. Increasing the energy density induced localized surface melt with a thin smooth glaze-like appearance. 4. In acid-etched control specimen cohesive failure predominated, whereas adhesive failure was the main mode in laser-treated group. Based upon the above-mentioned results, it can be assumed that the $CO_2$ laser is not an adequate substitute for the acid-etch technique in enamel preconditioning. More studies are required to explore the effective condition of laser irradiation which could attain the better bond strength of restorative materials.

• Textile Coloration and Finishing
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• v.27 no.3
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• pp.175-183
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• 2015

Weight loss treatment of a fiber leads an improvement of its handle and drape properties. Hydrolysis of a fiber is commonly known as a method to reduce its weight of 5-40%. Most of the studies on the weight loss treatment are mainly based on polyester fibers and there has been almost no study on the weight reduction of nylon fibers. In this study, however, in order to develop a use of nylon 6 fiber for the industrial applications such as toothbrush, underwear, carpet and more, weight loss treatment of a nylon 6 fiber was carried out. Under various treatment conditions, morphological analysis were done to observe the change in the structure of the surface and analysis. From the observation of formic acid treated nylon 6 fiber, there were many etched and deformed morphologies. Thermal and crystalline properties were analyzed to find the changes in the crystal structure caused by the weight loss treatment. There were little differences in the crystalline properties of nylon 6 fiber by formic acid treatment. Tensile strength of nylon 6 fiber decreases with acid concentration. The FITR peak intensity of the amide bond decreases with formic acid concentration.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.557-560
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• 2009

In this study, a new wet etching method and the solution for thinning the glass with the thickness below $100{\mu}m$ were investigated. For the preparation of etching solution with low hydrofluoric acid, it was effective to use $NH_4F$ or $NH_4HF_2$ as a main ingredient with the addition of sulfuric acid or nitric acid. Influence of the composition of mixed acid solution and the temperature on the etching rate was investigated. The addition of anionic surfactant provides the function to prevent the adhesion of sludge generated by the etching reaction. A new wet etching pilot device equipped with streaming generation parts was used to test etching of commercial non-alkali glass and soda lime glass. The non-alkali glass with the thickness of 640 ${\mu}m$ and soda lime glass with the thickness of $500{\mu}m$ were etched to $45{\mu}m$ and $100{\mu}m$, respectively, by using the pilot device. After the etching by pilot device, the roughness degree of the glass surface was maintained at $0.01{\sim}0.02{\mu}m$.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.375-381
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• 2007

Statement of problem. Prior to determining an optimal width of micropatterned grooves provided on titanium substrata, we have done a pilot study using surface topographies in combined microm and submicrom levels. Purpose. The purpose of this study was twofold 1) to assess the proliferation and 2) to analyze the expression of genes encoding the intracellular signaling proteins involved in cell-substratum adhesions and adhesion-dependent G1 phase cell cycle progression of human gingival fibroblasts plated on smooth and microgrooved/acid-etched titanium substrata. Material and methods. Three groups of titanium discs as NE0 (smooth Ti substrata), E15 (Ti substrata with microgrooves of $15{\mu}m$ of spacing and $3.5{\mu}m$ in depth and with further acidetching), and E30 (Ti substrata with microgrooves of $30{\mu}m$ spacing and $3.5{\mu}m$ in depth and with further acid-etching) served as the human gingival fibroblasts' substrata. Viability and proliferation of fibroblasts were determined using an XTT assay. Gene expressions of fibronectin, ${\alpha}5$ integrin, CDK4, and $p27^{kip}$ were analyzed in RT-PCR. Cell-substratum interactions were analyzed in SEM. Results. From the XTT assay at 24 h incubation, the mean optical density (OD) value of E15 was significantly greater than the values of E30 and NE0. At 48 and 96 h however, the mean OD values of E30 were significantly greater than the values of E15 and NE0. No differences in the expression of PCR transcripts at 96 h incubations were noted between groups, whereas at 48 h, an unexpected increase in the expression of all the transcripts were noted in E15 compared with other two groups. Fibroblasts were observed to orient and adhere inside the microgrooves. Conclusion. Micropatterned grooves and acid-etching on Ti substrata alter viability and gene expression of adhered human gingival fibroblasts.

• The korean journal of orthodontics
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• v.43 no.1
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• pp.23-28
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• 2013

Objective: The purpose of this study was to evaluate the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on the shear bond strength (SBS) of brackets bonded to non-demineralized teeth with either phosphoric acid etching or self-etching primer. Methods: Sixty human premolars were randomly assigned to 1 of 4 treatment groups (n = 15 each): phosphoric acid etching (group 1); self-etching primer (group 2); CPP-ACP for 2 weeks + phosphoric acid etching (group 3), and CPP-ACP for 2 weeks + self-etching primer (group 4). After bonding of the maxillary premolar metal brackets, specimens were subjected to shear forces in a testing machine. Scanning electron microscopy was used to observe etching patterns on the enamel surfaces of all teeth. A 2-way analysis of variance was used to test for effects of CPP-ACP and etching system on SBS. Results: Significantly higher mean SBSs were observed in groups subjected to phosphoric acid etching (i.e., groups 1 and 3; p < 0.05). On the other hand, SBSs did not appear to be influenced by CPP-ACP (i.e., groups 3 and 4; p > 0.05). We observed a uniform and clear etched pattern on the enamel surface of the phosphoric acid etching groups. Conclusions: CPP-ACP does not significantly affect the SBS of orthodontic brackets bonded to non-demineralized teeth, regardless of which adhesive method is used to bond the brackets.

• Restorative Dentistry and Endodontics
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• v.46 no.3
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• pp.36.1-36.11
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• 2021

Objectives: This study aimed to evaluate Emblica officinalis (Indian gooseberry or amla) as an acid etchant and matrix metalloproteinase (MMP) inhibitor, and to compare its effect on the microshear bond strength of composite resin with orthophosphoric acid (OPA) and 2% chlorhexidine (CHX) as an acid etchant and MMP inhibitor, respectively. Materials and Methods: The etching effect and MMP-inhibiting action of amla on dentin samples were confirmed by scanning electron microscopy (SEM) and gelatin zymography, respectively. Dentinal slabs (3 mm thick) from 80 extracted human molars were divided into 10 and 20 samples to form 2 control groups and 3 experimental groups. Groups 1, 2, and 4 were etched with OPA and groups 3 and 5 with amla juice. An MMP inhibitor was then applied: CHX for group 2 and amla extract for groups 4 and 5. Groups 1 and 3 received no MMP inhibitor. All specimens received a standardized bonding protocol and composite resin build-up, and were subjected to microshear bond strength testing. The force at which the fracture occurred was recorded and statistically analyzed. Results: Amla juice had a similar etching effect as a self-etch adhesive in SEM and 100% amla extract was found to inhibit MMP-9 by gelatin zymography. The microshear bond strength values of amla were lower than those obtained for OPA and CHX, but the difference was not statistically significant. Conclusions: Amla has a promising role as an acid etchant and MMP inhibitor, but further studies are necessary to substantiate its efficacy.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.211-221
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• 2010

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at $37^{\circ}C$, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment. For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.275-282
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• 2008

Objective: The purpose of this study was to investigate the effect of using laser for ceramic bracket bonding of porcelain surfaces and to compare it with conventional treatment of porcelain surfaces. Methods: Ninety feldspathic porcelain specimens were divided into 9 groups of 10, with each group having different surface treatments performed. Surface treatment groups were orthophosphoric acid, orthophosphoric acid with silane, hydrofluoric acid, hydrofluoric acid with silane, sandblasted, sandblasted with silane, laser etched, laser etched with silane, and glazed surface served as a control group. In the laser etched groups, the specimens were irradiated with 2-watt superpulse carbon dioxide ($CO_2$) laser for 20 seconds. Ceramic brackets were bonded with light-cure composite resin and all specimens were stored in water at $37^{\circ}C$ for 24 hours. Shear bond strength was determined in megapascals (MPa) by shear test at 1 mm/minute crosshead speed and the failure pattern was assessed. For statistical analysis, one-way ANOVA and tukey test were used. Results: Statistical analysis showed significant differences between the groups. The HFA + S group showed the highest mean shear bond strength ($13.92{\pm}1.94\;MPa$). This was followed by SB + S ($10.16\;{\pm}\;1.27\;MPa$), HFA ($10.09\;{\pm}\;1.07\;MPa$), L + S ($8.25\;{\pm}\;1.24\;MPa$), L ($7.86\;{\pm}\;0.96\;MPa$), OFA + S ($7.22\;{\pm}\;1.09\;MPa$), SB ($3.41\;{\pm}\;0.37\;MPa$), OFA ($2.81\;{\pm}\;0.37\;MPa$), G ($2.46\;{\pm}\;1.36\;MPa$), Bond failure patterns of HFA and silane groups, except L + S, were cohesive modes in porcelain while adhesive failure was observed in the control group and the rest of the groups. Conclusions : A 2-watt superpulse $CO_2$ laser etching of porcelain surfaces can provide a satisfactory result for porcelain surface treatment for ceramic bracket bonding. Laser irradiation may be an alternative conditioning method for the treatment of porcelain surfaces.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.115-119
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• 1983

The purpose of this study was to compare the solubility of enamel and dentin to an etchant after fluoride application. Specimens were collected from extracted anterior and bicuspid and each tooth was cut into several pieces. These specimen were allocated in 7 group; 1%, 2%, 3% NaF, 1%, 8%, 20% $SnF_2$, and control group. Five specimens in each group was exposed to pre-determined fluoride solution for 3 minutes, and washed with running water. These specimens were etched by Hipol (commercial label) etchant for 30 seconds. Following are the findings obtained through S.E.M. 1. All specimens with acid etching revealed preferential removal of prism periphery leaving prism core. 2. Specimens treated with 1%, 2% NaF solution showed that the shape of prism tip was thin and sharp like a needle. The case of 3% NaF showed rather round shape at prism end. 3.1% of $SnF_2$ case showed similar findings with the control group but 8% and 20% $SnF_2$ case revealed needle shape at the prism and was less clear than NaF case. Preferential removal of prism periphery was partialy observed and un decalcified area is fused to prism forming reidge. 4. Dentine treated by fluoride compound in low concentration showed the orifice of dentinal tubule was clearly enlarged whereas in high concentration the orifice was not widened.