• Restorative Dentistry and Endodontics
• /
• v.23 no.2
• /
• pp.682-689
• /
• 1998

The purpose of this study was to evaluate the sealing ability of the Microseal$^{(R)}$, which was new obturation system made by Tycom company, U.S.A. Forty-five extracted single-rooted human teeth were resected at cemento-enamel junction and divided three groups. All canals were prepared using Profile system, and then each group was obturated by lateral condensation technique (group 1), vertical condensation technique (group 2) and Microseal$^{(R)}$ condensation technique (group 3) with root canal sealer. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$ and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were resected horizontally at 1 mm (level I), 2 mm (level II), 3 mm (level III) from the anatomical root apex using low speed microtome and examined with Image analyzer (IBASR, Zeiss co., Germany.) at ${\times}25$ magnification. The gab between the canal wall and the filling material, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was expressed percentage by calculating the ratio of the area of the resin to the total area of the canal and was analyzed statistically (one-way ANOVA). The results were as follows; 1. The mean ratio of leakage (%) was 6.46% at group 1, 3.06% at group 2, 11.27% at group 3. 2. When evaluating the ratio of leakage at the three levels, there was level I> level II> level III in all groups. Especially, the difference between level I and level III was statistically significant (p<0.05). 3. When evaluating the ratio of leakage at the three groups, there was group 3> group 1> group 2 at all levels. Especially the difference between group 2 and group 3 was statistically significant (p<0.05).

• The Journal of the Korean dental association
• /
• v.56 no.10
• /
• pp.567-571
• /
• 2018

Obturation is a important procedure of root canal treatment. Canal filling should be both provide a hermetic seal for the root canal system and eliminate leakage channel from the oral cavity. Gutta-percha have been the standard material of choice for root canal obturation. Canal filling has been aimed at maximizing the amount of gutta-percha and minimizing the amount of sealer. However recently, single cone technique has been introduced that include calcium silicate-based sealer and single gutta-percha cone. It is important to select an obturation technique that offers consistency and is easy to use. From the standpoint of appropriate technology, the single cone technique is thought to be useful for general dentist.

• The Journal of the Korean dental association
• /
• v.20 no.12 s.163
• /
• pp.1025-1028
• /
• 1982

1) The authors have had a case of crown fractured upper central incisor with open apex and non vital pulp. 2) The patient was 8 years old female. 3) Apical closure has been induced with the use of calcium hydroxide and gutta percha cone. 4) At nine month after filling with calcium hydroxide and gutta percha cone, apical closure was observed by radiograph. 5) Root canal was permanently filled gutta percha cone and zinc oxide eugenol by the lateral condensation technique.

• Proceedings of the KACD Conference
• /
• 2001.11a
• /
• pp.592.2-592
• /
• 2001

The purpose of this study was to evaluate the efficiency of the four obturation techniques. In this study, eighty teeth were instrumented and randomly divided into 4 groups of 20 teeth each, according to the obturation techniques Group A was used with Microseal. in Group B, Thermafil. in Group C, continuous wave techniques, in Group D cold lateral condensation methods were used. After obturation, the teeth were taken a digital radiograph in mesiodistal and buccolingual directions to study the quality of the obturation.(omitted)

• Proceedings of the KACD Conference
• /
• 2001.11a
• /
• pp.587.1-587
• /
• 2001

The aim of this study is to compare the adaptability of thermoplasticized injectable gutta-percha technique to the canal walls in ribbon-shaped canals. Thirty resin models simulated ribbon-shaped canals were instrumented to ＃40 using. 06 taper Profile systems. Three groups of 10 resin models were obturated by the lateral condensation technique(LC) and the two thermoplasticized injectable gutta-percha technique; Ultrafil Endoset＋Obtura II(EO) and Ultrafil Firmset(UF), respectively.(omitted)

• Restorative Dentistry and Endodontics
• /
• v.25 no.3
• /
• pp.435-445
• /
• 2000

The purpose of this study was to compare the leakage of four different obturation techniques in conjunction with immediate apical barrier of ${\beta}$-tricalcium phosphate(TCP) in teeth with open apex. Eighty single-rooted human premolar teeth were prepared and sectioned horizontally, so maximum diameter in apex was 4mm. Apical defects that were similar to open apex, were created with #1/2 round bur and SF104R bur. The apical foramen were opened to a size 80 file extended 3mm beyond the apex. The teeth were placed into the oasis block soaked saline to simulate periapical tissue often associated with pulpless teeth and received apical barriers consisting of TCP followed by obturation using lateral condensation technique, vertical condensation technique, continuous wave technique and thermoplasticized gutta-percha injection technique. Two unobturated teeth served as positive and negative controls. Teeth were immersed in resorcinol-formaldehyde resin for S days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5mm(level 1), 2.5mm(level 2) and 3.5mm(level 3) from the apex, and examined under a stereomicroscope at ${\times}40$ magnification. The photographs were taken at ${\times}40$ magnification of the filling in each level and scanned. The leakage length in tooth/resin interface was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the leakage length of canal wall infiltrated with resin to the total length of the canal and was analyzed statistically(One-way ANOVA and Scheffe test). The result were as follows : 1. At the level 1, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), and the most leakage in the continuous wave technique group(group 3). There was statistically significant difference between the thermoplasticized gutta-percha injection technique group and the continuous wave technique group(p<0.05). 3. At the level 3, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there were no statistically significant differences between other groups(p>0.05). These results suggest that thermoplasticized gutta-percha injection technique which had 1mm apical gutta-percha matrix after the formation of TCP apical barrier, can demonstrate favorable apical sealing.

• Restorative Dentistry and Endodontics
• /
• v.25 no.1
• /
• pp.1-16
• /
• 2000

It is difficult to treat the endodontic apical perforation successfully. In this study, we hypothesized that the application of PDGF-BB and IGF-I into periapical perforation site may accelerate periapical healing and lead to bone deposition. And the specificity of osteonectin in periapical healing was investigated. The experiments were performed on the upper and lower 51 premolar teeth of 4 beagle dogs. The pulp chamber of each tooth was opened and the dental plaque was inserted into the canal for developing the periapical lesion for 5 weeks. Then, the roots were artificially perforated at the apex with the number 4 profile of .06 taper. In each step, standard periapical radiographs were taken to compare the size of lesion each other. The radiographs were scanned and analyzed by image analysis system. The mean and standard deviation of periradicular radiolucency ratios were calculated in each group. ANOVA was used for comparison. 51 premolars were grouped into 3 groups; control group, calcium hydroxide-treated group and calcium hydroxide plus growth factors-treated group. In the control group, the apical perforations were not sealed and obturated with gutta-percha and ZOE sealer by lateral condensation technique. In the experimental groups, the apical perforation were sealed with calcium hydroxide and with/without $4{\mu}g$ of PDGF-BB & IGF-I in cellulose gel and obturated by lateral condensation technique. Fluorescent bone markers were used to measure new bone formation. Following 2, 4, 12 weeks after experiment the dogs were sacrificed and histologic sections were prepared. Each tooth block including periapical lesion was sectioned mesiodistally. One half of the sections were decalcified with 6% nitric acid and processed by standard paraffin embedding technique. The sections were stained by hematoxylin and eosin, and immunostained for osteonectin. Histomorphometrical measurement of neoformed bone was performed using a light microscope. And the other half of the sections were prepared by undecalcified preparation, and confocal laser scanning microscopic investigations were done.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.105-112
• /
• 2005

Recently, Various structural systems for skyscrapers are studied as structures are more higher. The mega frame system of all, which is the structural system developed recently, are considered as a suitable structural system for skyscrapers. This structural system has sufficient stiffness for the lateral forces with mega-columns which consist of many columns and mega-girders which consist of girders with large stiffness or trusses. But there is no efficient analysis method and a design method for it. Therefore, an efficient analytical model, which has only DOFs selected by the user using the matrix condensation technique, is proposed in this study to obtain accurate results in significantly reduced computational time.

• Restorative Dentistry and Endodontics
• /
• v.24 no.2
• /
• pp.356-363
• /
• 1999

The purpose of this study was to compare the apical sealing effect of Microseal obturation technique with lateral condensation technique in 26 recently extracted single rooted teeth. The root canals were instrumented using step-back technique and obturated with laterally condensed gutta-percha or Microseal. Teeth were suspended in methylene blue dye for 2 days and then longitudinary splited. The apical microleakage and the adaptability of gutta-percha to the root canal wall were examined under a stereomicroscope at ${\times}20$ magnification. The results were as follows: 1. The mean leakage was 1.38${\pm}$1.18 mm for laterally condensed gutta-percha group, and 0.71${\pm}$0.57 mm for Microseal gutta-percha group. But there was no statistical difference between two groups. 2. In Microseal gutta-percha group, they showed no gap between the master cone and Microseal gutta-percha, and showed homogeneous mass. 3. In contrast, laterally condensed gutta-percha group showed some gaps not only between gutta-percha cones, but also between gutta-percha cones and the canal walls, and the gaps were filled with some sealer. And also this group showed some amout of sealer on the root canal walls, Within the limits of the results of this experiment, Microseal gutta-percha obturation technique demonstrated relatively favorable apical sealing effect and shorter obturation time. Thus, it is thought that this obturation technique is a acceptable method for clinical use but further studies on this matter should be conducted.

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