• Restorative Dentistry and Endodontics
• /
• v.21 no.1
• /
• pp.174-186
• /
• 1996

The purpose of this study was to evaluate the adaptability to tooth structure of composite resin and glass ionomer cement according to filling methods. In this study. two class V cavities were prepared on the buccal and lingual surface of each tooth of forty extracted human premolars. and they were randomly assigned into 4 groups with 10 teeth. The cavities of each group were filled with the CLEARFIL FII self curing resin(Control Group), Z-100 light curing resin (Group 1). $Vitremer^{TM}$ light curing glass ionomer cement(Group 2) and Z-100 light curing resin over the $Vitremer^{TM}$ liner(Group 3). The specimens underwent temperature changed from $5^{\circ}C$ to $55^{\circ}C$ five hundred times. After thermocycling. specimens were immersed in 2% methylene blue solution and stored in 100% relative humidity at $37^{\circ}C$ for 24 hours. And then. the specimens sectioned buccolingually. Degree of dye penetration at tooth-restoration interfaces were examined by Tool maker's microscope(x 200) and Image analyzer. The results were as follows : 1. On the occlusal margin. among the experimental groups. the group 2 showed the highest dye penetration($2.40{\pm}0.68$) and the group 3 showed the lowest dye penetration($1.15{\pm}0.37$). There was significant difference among the experimental groups(p<0.001). 2. On the gingival margin, among the experimental groups, the group 1 showed the highest dye penetration($3.30{\pm}0.57$) and the group 2 showed the lowest dye penetration($1.65{\pm}0.49$). There was significant difference among the experimental groups(p>0.001). 3. About total degree of dye penetration, the group 1 showed the highest dye penetration($2.25{\pm}1.17$) and the group 3 showed the lowest dye penetration ($1.43{\pm}0.55$). There was significant difference among the experimental groups(p<0.001). 4. The sum of dye penetration at occlusal margin was less than gingival margin. There was significant difference between occlusal margin and gingival margin (p<0.001). The results showed that differences were more pronounced at the gingival margin. Composite restorations inserted over the glass-ionomer liner demonstrated significantly less leakage than single restoration that used composite resin or glass-ionomer cement.

• Restorative Dentistry and Endodontics
• /
• v.19 no.2
• /
• pp.585-601
• /
• 1994

The purpose of this study was to evaluate the ability of several intracoronal base materials to prevent cervical leakage of a bleaching agent into the dentinal tubules and along the root canal. In this study, thirty-two anterior teeth were used. After lingual access was prepared in each tooth, tooth was instrumented with a step-back technique to a Nos. 40-50 using K-type files. All teeth were obturated with a lateral condensation technique. Excess gutta percha was removed with a warm instrument to the facial level of the CEJ. Teeth were divided into four groups : Teeth in control group were not filled with base material. Teeth in groups 1, 2, and 3 had 2mm of gutta percha removed with a warm instrument, then Dycal, Fuki II LC and Z-100 were filled with palstic instruments on the top of the gutta percha respectively. All teeth were bleached for 7 days, fresh bleach was added for another 7 days, then a 10 % methylene blue dye was placed inside the access preparation. They were stored at $37^{\circ}C$ and $100^{\circ}C$ humidity for 5 days. Each tooth was sectioned perpendicular to the long axis using a diamond disk. Initial cuts were made at the most coronal level of facial and lingual CEJ's, then another cuts continued appically in the levels of 0.5mm, 1.5mm, and 2.0mm respectively. The amount of dye leakage through the dentinal tubules was determined at each cut section. In addition, when the cut specimen was determined to be last penetration of any dye, this level was recorded as depth of apical leakage from the coronal terminus of the gutta percha, Dycal, Fuji II LC and Z-100. The acquired data were analyzed by Tukey's Multiple Range Test adn Cochran-Mantel-Haenszel Test to see if there was any statistically significant difference in dye penetration and linear apical leakage among the groups. The results were as follows : 1. Control group at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 AND 3 at level of 2.0mm showed the least dye penetration through the facial or lingual dentinal tubules, but there were no significant difference among three groups. 2. Group 2 at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 and 3 at level of 2.0mm showed the least dye penetration through the proximal dentinal tubules, but there were no significant difference among control group, group 2, and group 3. 3. Group 1 showed the greatest dye penetration through the facial or lingual and proximal dentinal tubules at all levels, and there were significant difference with other three groups. 4. Control group and group 1 showed 2mm apical dye leakage at facial or lingual and proximal aspects, group 2 showed 1.5mm, and group 3 showed 0.5mm.

• Restorative Dentistry and Endodontics
• /
• v.24 no.2
• /
• pp.392-398
• /
• 1999

The purpose of this study was to assess the effect of catalase used following bleaching for the elimination of hydrogen peroxide residues from human teeth on the microleakage at the tooth-resin composite interface. In this study, class V cavities were prepared on the buccal or lingual surfaces of seventy extracted human molar teeth, and crown of sixty teeth were immersed in 30% hydrogen peroxide at $37^{\circ}C$ for 5 days except for negative control group. Then the teeth were rinsed with water and distributed randomly into seven groups of 10 each and were conditioned as following Negative control group: No bleaching Positive control group : bleaching and no application of catalase (C-40) Experimental group 1 : one cycle of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 2 : two cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 3 : three cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 4 : four cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching Experimental group 5 : five cycles of catalase application for 3 min. and water rinse for 2 min. after bleaching The cavities of each groups were restored with composite resin. The teeth were thermocycled, stained with 2% methylene blue, and sectioned buccolingually. Degree of dye penetration at tooth-restoration interfaces were examined by stereomicroscope(${\times}30$) at occlusal and gingival margin The results were as follows : 1. On the occlusal margin, there was no significant difference in the microleakage between the negative coltrol group and experimental groups (p>0.05). But on the gingival margin, experimental groups showed higher microleakage than the negative coltrol group (p<0.05). 2. On the occlusal margin, positive coltrol group showed higher microleakage than experimental groups (p<0.05) and among the experimental groups, group 1 showed higher microleakage than group 3, 4, 5 (p<0.05). 3. On the gingival margin, there was no significant difference between the positive coltrol group and experimental groups, and between experimental groups (p>0.05). The result indicated that catalase used in bleached cavity for the elimination of hydrogen peroxide residues from human teeth maybe reduced microleakage at the tooth-resin composite interface.

• Restorative Dentistry and Endodontics
• /
• v.25 no.2
• /
• pp.170-179
• /
• 2000

The rh-BMP-4 is a subgroup of TGF-${\beta}$ superfamily. The application of rh-BMP in alveolar bony defect was reported to new alveolar bone and new cementum formation. For minimized complications following tooth replantation, a operator must replant a tooth fast at the pertinent position. This study was to evaluate the effect of rh-BMP-4 on periodontal regeneration and root resorption following tooth replantation in rats. The 50 Sprague-Dawley rats weighting about 130gm were used in this study. The animals were divided into three groups. Group 1 ; immediate replantation after extraction : Group 2 ; replantation stored teeth extraction of first molar, the removal of periodontal ligament with collagenase, and etching with citric acid : Group 3 ; replantation stored teeth with treated rh-BMP-4 in mesial root. Experimental animals were sacrificed 3, 7, 14 days after replantation by heart infusion. The maxillae were removed, fixed, demineralized, dehydrated, infiltrated and embedded with JB-4 mixture. For light microscopic observation, 5 micron sections were cut and stained with toluidine blue. The results of this study were as follows : 1. After experimental 3 days, all groups were observed dead space between periodontum and root. 2. After experimental 7 days, group 1 and group 3 were observed filling periodontal fibers between alveolar bone and root but group 2 were not. 3. After experimental 7 days, group 3 were observed appearance of attached cementoblast like cell on root surface. Group 1 were observed regular arrangement of fibroblasts and collagen fibers at ${\times}400$ observation. 4. After experimental 14 days, all group were observed filling periodontal fibers between alveolar bone and root. Group 1 were observed normal arrangement of periodontal fibers. Group 3 were observed less abnormal arrangement of periodontal fibers. Group 2 were not observed functional normal arrangement of periodontal fibers. 5. After experimental 14 days, group 2 and 3 were observed several root resorption and irregular root surface but group 1 were not. These results suggest that the rh-BMP-4 can stimulate cementogenesis and enhance to attach collagen fibers.

• Korean Journal of Ichthyology
• /
• v.27 no.2
• /
• pp.149-152
• /
• 2015

A single specimen of Symphorus nematophorus (481.0 mm in SL), belonging to the family Lutjanidae, was firstly collected by a set net in the coastal waters of Geojae Island, located in south sea of Korea on August 1, 2014. This specimen was characterized by having the anterior dorsal soft rays produced into filaments, a pit between eye and nostril, no tooth on vomer, and nine longitudinal blue strips on both sides of the body. We propose a new Korean name, "Sil-tung-dom-sok" and "Sil-tung-dom" for the genus and species, respectively.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.5
• /
• pp.104-111
• /
• 2009

A ship engine operator should compensate the crankshaft assembly of ship engine after inspecting crankshaft deflection error in the crank throw regularly to avoid engine vibration and abrasions. In the previous method, the operator enters the bed plate and measures crankshaft deflection using dial gauge on rotating crankshaft manually. However, this method can cause dangerous situation to the operator as well as uncomfortable in an inferior environment. In order to solve the problems, this paper studies the method which makes the operator measure the error outside of the bed plate. In this paper, it is suggested that BlueTooth wireless communication transfers the error data to the outer standing operator with digitalized crankshaft deflection inspection device developed in this paper. So, the wireless measurement system is developed and applied to a medium-speed marine engine through size-miniaturization. After applying test, the developed inspection device showed that it provides much safe and ease inspection method. Furthermore, in the result, the measuring accuracy is more improved.

• Restorative Dentistry and Endodontics
• /
• v.24 no.1
• /
• pp.116-128
• /
• 1999

치근흡수 연구에서 치아재식을 위한 적당한 동물모델을 찾는일은 대단히 중요하다. 본 실험에서는 쥐 대구치의 발치 및 재식을 통해서 치근흡수가 발현되는 모양을 관찰했다. 모두 20마리의 쥐(30일생)에게 0.4% ${\beta}$-APN(aminoproprionitrile)가 포함된 분말용쥐사료를 5일간 먹인후 케타민 마취후 상악좌우측 제일대구치를 손상을 최소화하여 발치 하였다. 발거된 쥐치아는 0.02M Tris-HCl로 표면처리하여 부착치근막을 제거한후 파라핀팍스로 치근단을 밀폐 하여 재식하였다. 재식후 1, 2, 4, 6, 8 및 12일이 경과된 후 심장관혈을 통하여 쥐를 희생시킨후 3% glutaraldehyde가 포함된 EDTA에서 탈회한후 Epon 포매 하였다. 모든 시편은 유리칼을 사용하여 1미크론 두께로 절편한후 veronal acetate buffer에 녹인 1% toluidine blue로 염색하였다. 파치세포양 세포에 의한 치근흡수는 재식 5-7일후 처음 관찰되었다. 재식 12일후에는 치근 전체에 걸친 광범위한 치근흡수가 관찰되었다. 이상의 결과 ${\beta}$-APN을 포함한 쥐사료 식이요법은 쥐 상악제일대구치의 발치와 재식을 용이하게 하여 일정한 치근흡수를 발현시키는데 많은 도움이 된 것으로 판단되었다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.4
• /
• pp.525-532
• /
• 2017

The system is consisted of arduino and sensors for protecting bicycle and safety of driver. The speed indicator is composed of speed alarms which are less than 15km/h, 15~30km/h, over 30km/h through limit switch. At that time, the accuracy is 96.6% compared to actual speed. Also, It gives a person warning ablut the obstacle of 5cm tall through ultrasonic sensor in night. Auto Lock System is operated to protect bicycle and the text message is sent to the user, if the bicycle lock was broken. This system puts emphasis on safety and usability, providing a application to know consuming calories.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.7
• /
• pp.1533-1540
• /
• 2012

u-Life care device collect body bio formation, and classify and store them in exercise patterns. Afterwards, the devices send the data through bluetooth wireless communication to the smart phones which set Google Android operation system at regular intervals. The information is checked out through application. u-Life care device calculates calories spent a day after monitoring activity quantity with 3-axis acceleration sensor. The device judges the status of health through body data mining and consults tailored exercise treatment. When sending body data, the device sends them in smart phone through Blue Tooth wireless communication at once. So, as a strong point, the device doesn't need mobile gateway or home gateway used for sending to web server information sensed from exercise life care products.

• Restorative Dentistry and Endodontics
• /
• v.14 no.1
• /
• pp.97-105
• /
• 1989

This study was conducted to evaluate and compare the apical leakage among the retrograde filling materials; retrograde filling with non-zinc amalgam, cavity varnish and non-zinc amalgam, z.o.e cement, Glass Ionomer cement, scotch bond and silux. Sixty single rooted teeth were divided into six groups and each tooth was individually prepared for its particular group. The specimens were incubated at $37^{\circ}C$ for 24 hrs and then were infiltrated by 2% methylene blue for 7 days. Apical leakage was evaluated by measuring the degree of dye penetration between the filling material and the canal wall. The results were as follows: 1. The scotch bond and silux group showed the least amount of apical leakage and the control group showed the greatest amount of apical leakage. 2. The groups retrofilled with cavity varnish and amalgam, glass-Ionomer cement, scotch bond and silux showed significantly good apical seal than control group. 3. The groups retrofilled with glass Ionomer cement, scotchbond and silux showed significantly good apical seal than the groups retrofilled with Amalgam and Zinc oxide eugenol cement.