• Restorative Dentistry and Endodontics
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• v.11 no.1
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• pp.27-32
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• 1985

The purpose of this study was to examine the influence of canal irrigants and smear layer on the property of apical seal. Fourty-five canals from human teeth were randomly selected and divided into 5 groups according to the irrigants used in conjunction with instrumentation. The irrigants were RC-prep in combination with Naocl, Citric acid, Naocl, Naocl in combination with $H_2O_2$, and normal saline solution. After instrumention and dry the canal with paper point, the canals were obturated by lateral condensation of Zinc-oxide eugenol sealer and gutta percha cone. All the specimens were immersed in 2% methylene blue dye solution for 7 days and the depth of dye penetration into the canals was evaluated by macros cope. The following results were obtained. 1. All the canals experimented showed varying degree of dye penetration. 2. There was no significant difference in depth of dye penetration between the groups known to be effective and ineffective in the removal of the smear layer. 3. The canals irrigated with NaOCl alone showed the highest dye penetration and mean leakage was 7.7 mm. 4. In the canals irrigated with RC-prep in combination with Naocl and citric acid, the mean dye penetration was 5.5 mm and 4.8 mm respectively, and the canals irrigated with NaOCl in combination with $H_2O_2$ and normal saline solution revealed mean dye penetration of 3.9 mm.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.202-217
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• 1996

The purpose of this study was to compare the degree of microleakage of Glass-Ionomer root canal sealer possessed several enviable properties with that of the other sealers and to evaluate clinical performance. One hundred twenty single-rooted teeth were used in this experiment. The teeth were cleaned mechanically and immersed for 24 hours in 5.25% sodium hypochlorite and clinical crowns then were removed. After the root canals were instrumented using a step-back technique. one hundred twenty single-rooted teeth were divided into five groups of 24 in each. Group 1 : Tubli-Seal(Kerr Co., MI, U.S.A/ZOE-based), lateral condensation Group 2 : Sealapex(Kerr/Sybron, Romulus, MI/ $Ca(OH)_2$-based), lateral condensation Group 3 : AH 26(De Trey Co., Zurich Switzerland/Resin-based), lateral condensation Group 4 : Ketac-Endo(ESPE GMBH & CO. KG Seefeld:oberbay. Germany/ Glass Ionomer Cement-based), lateral condensation Control group : no sealer. lateral condensation And then. the root canals were obturated by lateral condensation technique with gutta-percha and experimental sealers. The control group were obturated without sealer. The teeth were placed in a vacuum chamber for 15 minutes and immersed 2% methylene blue under vacuum for 15 minutes. The teeth were passively stained for 1 week and 2 weeks and were cleared and evaluated for linear dye leakage using Tool maker's microscope(${\times}200$). The results were as follows: 1. There were statistically significant differences in the degree of dye penetration between the control group and experimental groups(p<0.05). 2. In the experimental groups, Sealapex($1.2871{\pm}0.9180mm$) exhibited the lowest mean value of dye penetration, followed by Ketac-Endo($1.4432{\pm}0.8082mm$), AH 26($1.5030{\pm}0.7752mm$) and Tubli-Seal($1.6458{\pm}1.0292mm$)(p>0.05). 3. There were statistically significant differences in the variation of microleakage between 1 week and 2weeks in Tubli-Seal and Seal apex groups (p<0.05). 4. The degree of dye penetration of all groups were increased as the time elapsed and AH 26 showed the lowest variation(+0.11) and Tubli-Seal(+ 1.03) showed the highest variation (p<0.001).

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.789-801
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• 1995

Canals with artificially made internal resorption were filled with 4 techniques(Lateral condensation, Ultrafil, Obtura II, Thermafil) to compare the efficacy of canal filling according to the filling techniques. After canal filling, radiographic examination, dye penetration through the apical portion and percentage of G-P filled area on the internal resorption area were evaluated. To examine the degree of crystal-like structure and the interface between filled G-P and canal wall, SM and SEM images were taken too. The results were as follows : 1. There was no statistically significant difference in apical microleakage among the 4 root canal filling techniques. 2. As a result of radiographic examination, Ultrafil was the best and Obtura II was acceptable but Lateral condensation and Thermafil showed unfavorable canal filling pattern similarly. 3. Ultrafil filled most of artificially made internal resorption area and Obtura II, Lateral condensation, Thermafil in that order filled unfavorably. 4. Degree of crystal like structure was the highest in the group filled with Ultrafil and those of Obtura II and Thermafil were similar and that of gutta percha used in Lateral condensation showed the lowest value. 5. Penetration of gutta percha into the dentinal tubules couldn't be seen in all groups. In the contact surface between the filled G-P and the canal wall, Lateral condensation showed relatively close sealing, Obtura II and Thermafil had irregular contact surface and Ultrafil showed regular filling pattern. 6. Contact surface between the core of Thermafil and the gutta percha showed close relationship without gap formation.

• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.104-114
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• 1990

The purpose of this study was to evaluate the adaptation of root canal filling material to the dentinal wall of root canal and to compare the sealing ability of the root canal filling materials using ultrasonic endodontic instrument with injection-molded thermoplasticized gutta-percha filling method and lateral condensation method. Fifty fresh human single root exlracted for orthodontic treatment, were randomly selected, and instrumented by step-back technique. And then, the teeth were divided into 5 groups according to each root canal filling methods. In the experimental group 1 and group 2, the root canals were filled with gutta perdia cases using ultrasonic instrument with and without sealer. In the experimental group 3 and 4, using jection-moldeed thermoplasticized gutta-percha method by obtul$^{(R)}$ canals were filled with and without sealer. In the control group, the canals were filled with sealer by lateral candensation. And then, 5 teeth of each group were immersed in black Indian ink, decalcified and cleared. The depth of dye penetration into the root canal were evaluated with stereoscope (Reichert Ltd., USA). Among the 5 teeth remaining in each group, the single longituding grooves were made on the labial and lingual root surfaces and then immersed in the liquid nitrogen to fracture the teeth spontaneously without any distortions of gutta-percha. Each specimens were examined with X-650 Scanning Electron Microscope(Hitachi ltd, Japan) to show the adaptation to the canal wall, void, homogenicity of filling material and location of gutta-percha or sealer in the dentinal tubules of the root canal. The observations were as follows : 1. The experimental group 1 showed smaller mean dye penetration than control group, and showed the penetraton of sealer in the dentinal tubules of apical third of the root canal. 2. The experimental group 2 and group 4 showed the penetration of gutta-percha in the dentinal tubules of root canals. 3. The experimental group 1 and group 3 showed less mean dye penetration than the experimental group 2 and group 4. 4. The experimental group 1 and group 2 showed better adaptation of filling materials than control group.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.151-158
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• 1988

The purpose of this study was to evaluate the effect of canal filling methods and post-space preparation time on the apical seal of endodontically treated teeth. Seventy-six single-rooted human teeth were divided into 6 groups and each tooth was obturated and prepared post-space according to the purpose of this study. After all specimens were immersed in Indian ink, decalcified and cleared, the degree of dye penetration into the root canals observed by magnifying glass (X20) and measured by caliper. The results were as follows: 1. In the thermatic condensation, no significant difference in ink penetration occured when the post-spaces were created immediately after obturation or when they were made a week later. 2. In the lateral condensation, no significant difference in ink penetration existed between teeth whose post-space were prepared immediately or delayed. 3. In comparison of experimental groups and control groups, no significant difference showed when the groups were obturated with McSpadden compactor but when the teeth were laterally condensed, the experimental groups showed less ink penetration than controls. 4. Thermatic condensed teeth with McSpadden compactor were less ink penetration thn laterally condensed teeth.

• Journal of the Korea Furniture Society
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• v.19 no.2
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• pp.151-155
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• 2008

An experiment was conducted to observe the 5% CCFZ solution penetration depth through ray parenchyma and ray tracheid of Larix kapempferi. Moisture content was adjusted 28% for both sapwood and heartwood. Even though the moisture content was same, heartwood was 1.3 times less permeable than sapwood and the difference was found statistically significant. Due to anatomical differences between ray parenchyma and ray tracheid, ray parenchyma was about 1.3 times more permeable than ray tracheid. Penetration speed was high initially and it decreased rapidly in course of time.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.671-684
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• 1995

The purpose of this study was to compare the apical sealing ability, overfilling and obturation of lateral canals using two gutta-percha techniques: Thermafil obturators and cold lateral condensation. Eighty numbered epoxide blocks with one major and five lateral canals were divided into four experimental groups and obturated according to experimental groups. Four experimental groups were as follows: Group 1 : Filling with Thermafil plastic obturators and sealer(ThermaSeal) Group 2 : Filling with Thermafil plastic obturators only, without sealer(ThermaSeal) Group 3 : Fillng using lateral condensation with sealer(AH-26) Group 4 : Fillng using lateral condensation without sealer(AH-26) All the blocks were stored in 100% relative humidor at room temperature for 7 days. Each block was placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. Apical leakage was measured from the apical foramen to the most coronal level of dye penetration in millimeter under a stereoscope. The length of gutta-percha and sealer in each of the lateral canals was measured, too. The presence or absence of overfilling of gutta-percha and sealer was recorded. The data was analyzed by one-way ANOVA. The obtained results were as follows: l. Apical dye leakage was almost: not occurred in Group Willed with Thermafil and sealer) and Group 3(filled using lateral condensation with sealer), and there was no significant difference in linear leakage between two groups(p>0.01). 2. In both Thermafil and lateral condensation groups, linear leakage of Group I, 3(filled with sealer) was less than that of Group 2, 4(filled without sealer), and there was no significant difference in linear leakage between Group 1, 2, 3(p> 0.01). 3. Overfilling during obturation of Group 1, 2(filled with Thermafil) was more than Group 3, 4(filled using lateral condensation), and there was no significant difference between groups(p> 0.05). 4. Groups filled with Thermafil had significantly more gutta-percha than groups filled using lateral condensation in all lateral canals(p <0.01), the total length of gutta-percha and sealer found in all lateral canals were similar in Group 1 and Group 3.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.161-166
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• 1982

The purpose of this study was to examine the influence of canal preparation on the property of apical seal. Seventy canals from extracted human maxillary and mandibular teeth were randomly selected and divided into two groups: conventional group and step-back group. Thirty five canals in one group were enlarged with a, conventional preparation method and thirty five canals in the other group were instrumented in a step-back method with K-file. After instrumentation sixty canals were obturated by lateral condensation of gutta percha and zinc oxide eugenol cement, and five canals in each group were not filled and used as control. All the specimens were immersed in 2% methylene blue dye solution and the depth of dye penetration into the canals were observed by macroscope at the intervals of 1 day, 2 days, and 7 days. The following results were obtained. 1. All the canals experimented showed varying degrees of dye penetration. 2. There was no significant difference between conventional method and step-back method in the depth of dye penetration and the degree of dye penetration tended to increase with time passage in both groups. 3, In conventional preparation group the mean dye penetration was 3.6mm at 1 day, 4.8mm at 2 days. and 6.5mm at 7 days. 4. In step-back prepareation group, the specimens exposed to the dye for 1 day showed mean dye penetration of 4.1mm, and the specimens immersed in the dye for 2 days and 7 days revealed mean dye penetration of 4.6mm and 6.2mm respectively.

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.31-37
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• 1989

The purpose of these study was to compare the sealing ability of a injection-molded thermoplasticized gutta-percha and silver amalgam as retroseal material in vitro. Sixty two upper and lower extracted human teeth with single root were randomly selected and instrumented in a conventional method with H-file. After instrumentation the root canal was obturated with gutta-percha by lateral condensation technique with AH26 and an apicoectomy was performed by beveling the root tip 45 angle. In the experimental group 1 and 2, a class I preparation was made and filled with silver amalgam or gutta-percha and in the experimental group 3 an apicoectomy only was performed. All specimens were immersed in black Indian ink, decalcified and cleared. The depth of dye penetration into the canals were evaluated by califer. The results were as follows ; 1. The experimental group 1 displayed the smallest mean dye penetration as 0.45mm. 2. The experimental group 3 displayed the greatest mean dye penetration as 0.65mm. 3. There was the difference in dye penetration between each group, but the difference was not statistically significant(P>0.05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2760-2766
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• 2013

Introduction : The projection method to check existence and nonexistence of radius groove penetration of screw after distal radius fracture operation clinical using the T-type plate and the radiation of radial groove tangential is to propose a new test. Material and Methods : On the tangential projection view of radius groove, elevation angle of distal radius is 2.5, 5, 7.5, 10 degree. and forearm and radiation detector of angle is 60, 70, 80, degree each changed. that analyzed check existence and nonexistence of radius groove penetration of screw. Results : For the image of Radial groove tangential. the case of not radius groove penetration of screw(63.95%, n=55), medial penetration of radius groove(10.47%, n=9) or lateral penetration of radius groove(25.58%, n=22) was analysis. The radius groove penetrating of screw length was a range of 0.43 ~ 2.72mm, the average was 1.06mm. the check existence and nonexistence of radius groove penetration of medial or lateral was analysis that it accurate for the image of Radial groove tangential. the radiography of radial groove is well described elevation angle of distal radius 2.5 to 7.5 degree(90% over), forearm and radiation detector of angle 70degree(80%over) Conclusion : It is elevation angle of distal radius is 5degree, forearm and radiation detector of angle 70degree recommended.