• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.514-521
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• 2009

The aim of this study was to evaluate the bonding ability of two self etch systems to human primary and permanent enamel and the effect of additional acid etching time. Exfoliated, caries free human primary molar(n=65) and permanent molar extracted (n=65) were used. prepared enamel specimens were randomly divided into 2 test groups and a control group. The control group(n=10) were treated with 35% phosphoric acid gel and Scotchbond Multi-purpose adhesive. Experimental groups(self-etching systems) were subdivided into 6 groups(each n=10) according to additional etching time(0s, 5s, 10s, 15s, 20s, 30s). The result were as follows : 1) The shear bond strengths of the self-etching adhesives(Clearfil SE Bond, Adper Prompt L-pop) without additional etching were lower than control group(Scotch Bond Multipurpose). 2) Between the same self-etch adhesive groups, additional etched groups showed higher shear bond strength 3) There was no significant difference between primary and permanent enamel. In conclusion, bond strength of self-etch adhesives to enamel could be increased with additional etching.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.185-190
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• 2004

자가산부식 접착제 (self-etching primer)는 법랑질과 상아질을 동시에 산부식과 프라이머 처리를 함으로 임상 시술 시간을 단축시킬 뿐만 아니라, 임상과정 중 발생할 수 있는 술자의 실수 및 타액등에 의한 오염의 가능성을 줄일 수 있는 장점을 가지고 있다. 그러나 약산을 이용한 산부식법이 법랑질에 대해 탈회효과 및 접착강도에 있어 논란이 되고 있다. 이에 본 연구에서는 인산을 이용한 추가적인 산부식 및 자가산부식 접착제의 적용시간을 달리할 경우 법랑질에 대한 접착강도의 변화를 알아보고자 하였다. 135개의 발거한 우치의 법랑질 면을 ＃600사포로 연마한 후 9개의 군으로 분류하였다. 각 군은 부가적인 32% 인산을 처리하지 않은 군 (1~3군), 15초간 처리한 군 (4~6군), 60초간 처리한 군 (7~9군)으로 나누고, 이를 다시 Clearfil SE Bond의 프라이머로 5초 (1, 4, 7군), 20초 (2, 5, 8군), 60초 (3, 6, 9군)간 처리한 군으로 분류하였다. 접착제 처리한 면에 Clearfil AP-X 복합레진을 접착하고 24시간 경과 후 전단응력 강도를 측정하였다. 결과는 One-way ANOVA 처리후 Duncan's multiple range test로 사후검증하였다. 동일한 자가산부식 프라이머 처리 시간을 가진 군에서 산 부식을 한 경우가 그렇지 않은 군에 비해 높은 접착강도를 나타내었으며 인산부식 시간의 차이에 의한 영향은 없었다.(1 < 4, 7군/ 2 < 5, 8군/ 3 < 6, 9군). 자가산부식제의 프라이머 적용 시간에 의한 효과는 1군(5초 적용)을 제외한 나머지 군의 경우 동일한 인산 처리군에서는 차이가 없는 것으로 나타났다.(1군 < 2, 3군/ 4＝5＝6군/ 7＝8＝9군). Clearfil SE Bond 접착제의 법랑질에 대한 접착강도는 부가적인 산부식을 통하여 증가시킬 수 있으며 프라이머의 적용 시간에 의한 효과는 제조자의 지시에 의한 시간 이상 적용할 경우 차이가 없는 것으로 나타났다.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.143-152
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• 2003

The aims of the present study was to observe resin tag of the resin/enamel, dentin interface produced by self-etching adhesive systems and evaluate effect of additional acid etching on resin tag formation. Three self-etching primer(SE bond, AQ bond and L Pop) and an one bottle adhesive(Single bond) were used. Flat occlusal enamel and dentin disks were obtained from extracted human molars. A total of 20 surfaces were collected and divided into four groups of 5 samples. One-half of each specimen in each group was etched with 35% phosphoric acid prior to the application of each adhesive system, with the second half being kept unetched. Subsequently, resin composite was placed and polymerized. The samples were sliced and immersed into HCl and NaOCl solutions, followed by drying and sputter coating for examination with a SEM. The results were as follows; 1. Additional etching side of dentin displayed longer and thicker resin tag than unetched side in all self-etching adhesive groups. 2. In enamel, additional etching side displayed deeper and more distinct etching pattern than unetched side except L Pop. There is no difference between etched and unetched enamel in L Pop. The results obtained suggest the self-etching adhesive did not etch enamel and penetrate into dentinal tubule as deeply as did additional etching. Further research should include the evaluation of the relationship of boding strength, microleakage and resin tag morphology.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.443-451
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• 2008

The purpose of this study was to evaluate the effect of additional etching procedure prior to Maxcem resin cement application in indirect restoration cementation using push-out bonding strength. One hundred and two extracted human molars were used to make indirect resin restorations of gold inlay and Synfony. These restorations were cemented using Maxcem and Variolink II. Additional etching procedures were done for one group with Maxcem. Three groups have 17 specimens in both restoration types. Push-out bond strength was measured using multi-purpose tester and calculated for bonding strength per sqaure-millimeter area. The mean bonding strength values were compared using SPSS 12.0K program for one-way ANOVA and Scheffe's Test with 95% significance. Under the condition of this study, the additional etching procedure prior to usage of Maxcem resulted in reduced bond strength for both of restoration types.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.263-268
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• 2006

Recently, self-etching adhesive system has been introduced to simplify the clinical bonding proce- dures. It is less acidic compared to the phosphoric acid, thus there is doubt whether this system has enough bond strength to enamel. The purpose of this study was to investigate the influence of additional etching on the adhesion of resin composite to enamel. Ninety extracted bovine permanent anterior teeth were used. The labial surfaces of the crown were ground with 600-grit abrasive paper under wet condition. The teeth were randomly divided into six groups of 15 teeth each. Clearfil SE $Bond^{\circledR},\;Adper^{TM}$ Prompt L-Pop and Tyrian $SPE^{TM}$ were used as self-etching primers. Each self-etching primers were applied in both enamel specimens with and without additional etching. For additional etching groups, enamel surface was pretreated with 32% phosphoric acid (UNI-ETCH, Bisco, Inc., Schaumburg, IL. USA). Hybrid resin composite Clearfil AP-X, (Kuraray Co., Ltd., Osaka, Japan) was packed into the mold and light-cured for 40 seconds. Twenty-four hours after storage, the specimens were tested in shear bond strength. The data for each group were subjected to independent t - test at p < 0.01 to make comparisons among the groups. In Clearfil SE $Bond^{\circledR}$, shear bond strength of additional etching group was higher than no additional etching group (p < 0.01). In $Adper^{TM}$ Prompt L-Pop and Tyrian SPE, there were no significant difference between additional etching and non-etching groups (p > 0.01). In conclusion, self-etching adhesive system with weak acid seems to have higher bond strength to enamel with additional etching, while self-etching adhesive system with strong acid seems not.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.692-699
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• 2008

The purpose of this study was to evaluate the effect of surface treatment on the shear bond strength between new and old composite resin. The prepared resin specimens were separated 6 groups, and each group then received a different surface treatment. Then the repair material was added. Shear bond strengths for repair were measured after 7 days and the results were analyzed by using one way ANOVA. The results were as follows; 1. Group 3, 4(air abrasion) showed significantly higher shear bond strength than Group 1(phosphoric acid)(p<0.05). Group 5, 6(diamond bur) showed higher bond strength than Group 1(phosphoric acid) but not significantly different( p>0.05). 2. Group 2(self-etching adhesive) showed lower shear bond strength than Group 1(phosphoric acid) but not significantly different(p>0.05). 3. There was no statistically significant difference between Group 3(air abrasion) and Group 4(air abrasion+etching). 4. There was no statistically significant difference between Group 5(diamond bur) and Group 6(diamond bur+etching). In conclusion, the surface treatment with air abrasion resulted in higher repair bond strength than other methods. Repair bond strength was not significantly affected by acid etching.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.437-445
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• 2008

The presence of a "prismless" layer on the enamel surface particularly on deciduous teeth has been reported by a number of workers. This structure, which appears to lack the normal prism delineations, could interfere with tag formation and hence, reduce bonding to such surfaces. The purpose of this study was to investigate the relationship of etching times on the effect of acid etching on primary enamel with respect to the quality of etching patterns. Labial surfaces of 32 extracted or exfoliated caries-free primary anterior teeth were used. 35% phosphoric acid gel was used only cervical regions of labial surfaces for each etching time group, 15, 30, 45 and 60 seconds. The surfaces were then washed with water for 20 seconds and dried with air spray for 20 seconds. 1. The Type 3 is 75% when the 15 seconds acid etching time was used. 2. The Type 1 is 38% and Type 2 is 75% when the 30 and 45 seconds acid etching time was used. 3. The Type 1 is 25% and Type 2 is 75% when the 60 seconds acid etching time was used. 4. An etching time of 60 seconds produced a constant and regular etching pattern. 5. There is a significant difference between the groups with respect to the patterns of etch achieved(p<0.05). 6. We confirmed that the acid induced patterns(type 1, 2) became more pronounced when the application time increased(p<0.05). $45{\sim}60$ seconds was the optimal time for etching on the primary enamel.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.4
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• pp.35-41
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• 2000

In this paper, the multiplicative algorithm of two polynomals over finite field GF(2$^{m}$ ) is presented. The proposed algorithm permits an efficient realization of the parallel multiplication using iterative arrays. At the same time, it permits high-speed operation. This multiplier is consisted of three operation unit: multiplicative operation unit, the modular operation unit, the primitive irreducible operation unit. The multiplicative operation unit is composed of AND gate, X-OR gate and multiplexer. The modular operation unit is constructed by AND gate, X-OR gate. Also, an efficient pipeline form of the proposed multiplication scheme is introduced. All multipliers obtained have low circuit complexity permitting high-speed operation and interconnection of the cells are regular, well-suited for VLSI realization.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.4
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• pp.419-426
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• 2017

Attachment of the orthodontic bracket conducted during the window opening procedure can result in failure due to various adverse conditions such as blood or saliva contamination, or other wet conditions. For the success of the bracket attachment, reduction of total operation time is crucial. The purpose of this literature is to evaluate the differences between the final resultant shear bond strength of the conventional method of using phosphoric acid and self-etching primer, and that of the operation time-reduced method in which the curing step is omitted subsequent to the primer application. A total of 40 human maxillary incisors were prepared. Group I(control group) and II were etched with 37% phosphoric acid and Group III and IV were conditioned with self-etching primer. Attachment of the group I and III was conducted by manufacturer's instructions. The operation time of Group II and IV was reduced by eliminating the curing step after the primer application. The resultant shear bond strength of each group was measured and an adhesive remnant index (ARI) was recorded. The mean shear bond strength of group I, II, III, and IV were 14.16 MPa, 8.33 MPa, 8.29 MPa, and 6.48 MPa respectively. Significant differences could only be found between the control group and the experimental groups (p < 0.05). The ARI indicated no significant difference among all groups.

• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.555-560
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• 2002

치근부 민감성 (hypersensitivity)은 부분적으로 치근면에서의 개방된 상아세관이 존재하는 것에 기인한다고 생각되며 이러한 치근부의 개방된 상아세관은 치경부 병소 (cervical lesion)에 주로 존재하는데 이는 칫솔질에 의한 마모(toothbrush abrasion), 화학적 침식 (chemical erosion), 또는 abfraction 등의 결과로 나타난다고 한다. 이미 Nd-YAG 레이저를 이용한 실험에서 레이저를 조사한 상아질 표면의 상아 세관 구경이 감소되고 상아세관의 폐쇄가 많이 증가되는 양상을 관찰한 바 있다. 이 실험의 목적은 고출력레이저인 Nd-YAC 레이저를 이용한 상아질 표면처치의 임상사용가능성을 좀 더 상세히 평가하기 위해 상아질에 레이저를 처리한 후 기계적으로 마모시킨 경우 상아질 표면의 변화를 관찰하는 것이다. 50개의 발치된 치아의 상아질을 노출시켜 표면을 연마한 후 대조군에서는 37% 인산으로 산부식하여 상아 세관을 노출시킨 후 레이저를 조사하였고, 실험군에서는 대조군과 같은 조건으로 산과 레이저로 처리된 상아질 표면을 15, 45, 90 그리고 180분 동안 전동 칫솔로 기계적으로 마모시켜 그 표면을 주사전자현미경으로 관찰한 결과, 대조군, 칫솔질을 15, 45분간 시행한 실험군에서는 상아 세관 입구가 10% 이내에서 노출되었고 50 그리고 180분간 칫솔질을 시행한 실험군에서는 45 그리고 48%의 상아세관 입구의 노출이 관찰되었다. 그러므로 Nd-YAC레이저의 조사는 상아질 표면에서 축적 시간이 45분 이상에서 90분 이하인 기계적 마모에 의한 상아 세관 입구의 노출을 억제할 수 있을 것이라 사료된다.