• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.365-376
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• 2007

The purpose of this study was to evaluate the effect of different etching times on microtensile bond strength (${\mu}TBS$) to dentin both initial and after thermocycling with 3 different types of total-etching adhesives. Fifty four teeth were divided into 18 groups by etching times (5, 15, 25 sec), adhesives types (Scotchbond Multipurpose (SM), Single Bond (SB), One-Step (OS)) and number of thermocycling (0, 2,000 cycles). Flat dentin surfaces were prepared on mid-coronal dentin of extracted third molars. After exposed fresh dentin surfaces were polished with 600-grit SiC papers, each specimen was acid-etched with 35% phosphoric acid (5, 15, 25 sec) and bonded with 3 different types of total etching adhesives respectively. Then, hybrid composite Z-250 was built up. Half of them were not thermocycled (control group) and the ethers were subjected to 2,000 thermocycle (experimental group). They were sectioned occluso-gingivally into $1.0\;{\times}\;1.0\;mm^2$ composite-dentin beams and tested with universal testing machine at a crosshead speed of 1.0 mm/min. Within limited data of this study, the results were as follows 1. There was no statistically significant difference in ${\mu}TBS$ between the thermocycled and non-thermocycled groups, except for both SM and SB etched for 25 sec. 2. In thermocycled SM and SB groups, bond strength decreased by extended etching time. In total etching systems, adhesive durability for dentin could be affected by type of solvents in adhesive and etching time. Especially, extended etching time may cause deteriorate effects on bond strength when ethanol-based adhesive was used.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.207-214
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• 2012

Objectives: This study evaluated the influence of chlorhexidine (CHX) on the microtensile bonds strength (${\mu}TBS$) of resin core with two adhesive systems to dentin in endodontic cavities. Materials and Methods: Flat dentinal surfaces in 40 molar endodontic cavities were treated with self-etch adhesive system, Contax (DMG) and total-etch adhesive system, Adper Single Bond 2 (3M ESPE) after the following surface treatments: (1) Priming only (Contax), (2) CHX for 15 sec + rinsing + priming (Contax), (3) Etching with priming (Adper Single Bond 2), (4) Etching + CHX for 15 sec + rinsing + priming (Adper Single Bond 2). Resin composite build-ups were made with LuxaCore (DMG) using a bulk method and polymerized for 40 sec. For each condition, half of specimens were submitted to ${\mu}TBS$ after 24 hr storage and half of them were submitted to thermocycling of 10,000 cycles between $5^{\circ}C$ and $55^{\circ}C$ before testing. The data were analyzed using ANOVA and independent t-test at a significance level of 95%. Results: CHX pre-treatment did not affect the bond strength of specimens tested at the immediate testing period, regardless of dentin surface treatments. However, after 10,000 thermocycling, all groups showed reduced bond strength. The amount of reduction was greater in groups without CHX treatments than groups with CHX treatment. These characteristics were the same in both self-etch adhesive system and total-etch adhesive system. Conclusions: 2% CHX application for 15 sec proved to alleviate the decrease of bond strength of dentin bonding systems. No significant difference was shown in ${\mu}TBS$ between total-etching system and self-etching system.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.2
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• pp.62-66
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• 2004

This paper investigated the characteristics of a newly developed high density hollow cathode plasma (HCP) system and its application for the etching of silicon wafers. We used SF$_{6}$ and $O_2$ gases in the HCP dry etch process. Silicon etch rate of $0.5\mu\textrm{m}$/min was achieved with $SF_6$$O_2$plasma conditions having a total gas pressure of 50mTorr, and RF power of 100 W. This paper presents surface etching characteristics on a crystalline silicon wafer and large area cast type multicrystlline silicon wafer. The results of this experiment can be used for various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications.s.

• Journal of Information Display
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• v.2 no.4
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• pp.1-7
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• 2001

This paper investigates the characteristics of a newly developed high density hollow cathode plasma(HCP) system and its application for the etching of silicon wafers. We used $SF_6$ and $O_2$ gases in the HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}cm^{-3}$ at a discharge current of 20 rna, Silicon etch rate of 1.3 ${\mu}m$/min was achieved with $SF_6/O_2$ plasma conditions of total gas pressure of 50 mTorr, gas flow rate of 40 seem, and RF power of200W. This paper presents surface etching characteristics on a crystalline silicon wafer and large area cast type multicrystlline silicon wafer. We obtained field emitter tips size of less than 0.1 ${\mu}m$ without any photomask step as well as with a conventional photolithography. Our experimental results can be applied to various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this research, we studied silicon etching properties by using the hollow cathode plasma system.

• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.222-235
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• 2007

The objectives of this study was to evaluate the effect of thermocycling on the ${\mu}TBS$ (microtensile bond strength) to dentin with four different adhesive systems to examine the bonding durability. Freshly extracted $3^{rd}$ molar teeth were exposed occlusal dentin surfaces, and randomly distributed into 8 adhesive groups 3-steps total-etching (Scotchbond Multi-Purpose Plus; SM, All Bond-2; AB), 2-steps total-etching (Single Bond; SB, One Step plus; OS), 2-steps self-etching (Clearfil SE Bond; SE, AdheSE AD) and single-step self-etching systems (Promp L-Pop; PL, Xeno III; XE) Each adhesive system in 8 adhesives groups was applied on prepared dentin surface as an instruction and resin composite (Z250) was placed incrementally and light-cured. The bonded specimens were sectioned with low-speed diamond saw to obtain $1\times1mm$ sticks after 24 hours of storage at $37^{\circ}C$ distilled water and proceeded thermocycling at the pre-determined cycles of 0, 1,000 and 2,000. The ${\mu}TBS$ test was carried out with EZ-tester at 1mm/min. The results of bond strength test were statistically analyzed using one-way ANOVA/ Duncan's test at the a < 0.05 confidence level. Also, the fracture mode of debonded surface and the interface were examined under SEM. The results of this study were as follows ; 1. 3-step total etching adhesives showed stable, but bond strength of 2-step adhesives were decreased as thermocycling stress. 2. SE showed the highest bond strength, but single step adhesives (PL, XE) had the lowest value both before and after thermocycling. 3 Most of adhesives showed adhesive failure. The total-etching systems were prone to adhesive failure and the single-step systems were mixed failure after thermocycling. Within limited results of this study, the bond strength of adhesive system was material specific and the bonding durability was affected by the bonding step/ procedure of adhesive Simplified bonding procedures do not necessarily imply improved bonding performance.

• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.385-396
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• 2011

Objectives: This study evaluated the effects of adhesion variables such as the priming concepts of canal wall and the curing modes of adhesives on the sealing ability of a resin-based root canal filling system. Materials and Methods: Apical microleakage of the Resilon-RealSeal systems filled with 3 different combinations of adhesion variables was compared with the conventional gutta-percha filling using a dye penetration method. Experimental groups were SEDC, Resilon (Resilon Research LLC) filling with self-etch RealSeal (SybronEndo) primer and dual-cure RealSeal sealer; NELC, Resilon filling with no etching, Scotchbond Multi-Purpose (3M ESPE) primer application and light-curing adhesive; and TELC, Resilon filling with Scotchbond Multi-Purpose primer and adhesive used under total etch / wet bonding and lightcure protocols. GPCS, gutta-percha filling with conventional AH26 plus sealer, was the control group. Results: The median longitudinal dye penetration length of TELC was significantly shorter than those of GPCS and SEDC (Kruskal-Wallis test, p < 0.05). In the cross-sectional microleakage scores, TELC showed significant differences from other groups at 2 to 5 mm from the apical foramen (Kruskal-Wallis test, p < 0.05). Conclusions: When a resin-based root canal filling material was used, compared to the self-etching primer and the dual-cure sealer, the total etch/wet-bonding with primer and light-curing of adhesive showed improved apical sealing and was highly recommended.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.

• 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.28 no.2
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• pp.169-177
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• 2003

본 연구는 total etching (Scotchbond Multi-Purpose; MP) 및 self-etching (Clearfil SE Bond; SE 과 Prompt L-pop LP) 상아질 접착제의 nanoleakage 양상을 관찰하고 열순환 후의 nanoleakage 양상의 변화를 분석하고자 하였다. 30개의 발거된 치아의 교합면 및 협, 설측 법랑질을 제거하였다. 열 순환 시행 여부에 따라 두 군으로 나누어 실험하였으며 각각의 상아질 접착제 도포 후 Z-250으로 교합면을 수복하였다. Silver nitrate용액 및 현상액에 침적 후치아의 협설 방향으로 평행하게 절단하여 SEM으로 관찰하였다. 서로 다른 양상의 nanoleakage가 관찰되었다. MP의 경우는 resin tag 주위로 뚜렷한 은의 침착을 관찰 할 수 있었으며 혼합층 전체 두께에 띠 및 점상으로 흩어져 침착된 은을 관찰 할 수 있었다. SE의 경우는 혼합층의 하층을 따라 은으로 침착된 선을 관찰 할 수 있었으며 혼합층과 adhesive 경계를 따라 무정형의 은 침착물 들을 관찰할 수 있었다. LP의 경우는 혼합층의 하부 및 혼합층 내에 띠 모양으로 은의 침착을 관찰 할 수 있었으며 혼합층의 하부에서는 관찰되지 않고 혼합층의 내부에서만 관찰되는 경우도 있었다. 열순환을 시행한 군에서는 전반적 nanoleakage 양상은 열 순환을 시행하지 않은 군과 유사하였으나 은 침착의 증가를 관찰 할 수 있었다.