• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.80-88
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• 2003

Object The purpose of this study were to evaluate the microtensile bond strength of resin fiber reinforced post to radicular dentin using resin cement according to various dentin surface treatment and to observe the inter face between post and root dentin under SEM Material and Method A total 16 extracted human single rooted teeth were used. A lingual access was made using a #245 carbide bur in a high-speed handpiece with copious air water spray. The post space was mechanically enlarged using H-file(up to #60) and Gates Glidden bures(#3). This was followed by refining of the canal space using the calbrating drill set provided in ER Dentinpost(GEBR, BRASSELER GmbH&Co. KG). The 16 teeth were randomly distributed into 4 group of 4 teeth. Group 1 teeth had their post space prepared using 10% phosphoric acid as root canal surface treatment agent during 20s. The canal was then rinsed with saline and dried with paper point. Group 2 teeth had their post space prepared using 3% NaOCl as root canal surface treatment agent during 30min. The canal was then rinsed with saline and dried with paper point. Group 3 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. The canal was then rinsed with saline and dried with paper point. Group 4 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. After rinsing with saline, the canal was rinced 10m1 of 3% NaOCl for 30min. After drying with paper point, the post(ER Dentinpost, GEBR, BRASSELER GmbH&Co. KG) was placed in the treated canals using resin cement. Once the canal was filled with resin cement(Super bond C&B sunmedical co. Ltd.), a lentulo was inserted to the depth of the canal to ensure proper coating of the root canal wall. After 24 hours, acrylic resin blocks($10{\cdot}10{\cdot}50mm$) were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strengths for each stick was measured with Microtensile Tester. Failure pattern of the specimen at the interface between post and dentin were observed under SEM. Results 1. Tensile bond strengths(meen{\pm}SD$) ) were expressed with ascending order as follows group 4, $12.52{\pm}6.60$ ; group 1, $7.63{\pm}5.83$ ; group 2, $4.13{\pm}2.31$ ; group 3, $3.31{\pm}1.44$. 2. Tensile bond strengths of Group 4 treated with 17% EDTA +3%NaOCl were significant higher than those of group 1, 2 and 3 (p<0.05). 3. Tensile bond strengths of Group 1 treated with 10% phosphoric acid were significant higher than those of group 2 (p<0.05). Tensile bond strengths of Group 4 treated with 17% EDTA +3% NaOCl was significant higher than those of other groups.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.68-73
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• 1996

Stem length, main root length and main root diameter showed rapid increasement in two-years-old and three-years-old peony. And there after, the increasement was almost finished. Occurrence of disease was increasing every cultivated year, especially the development of leaf spot was most serious. In propagation by root dividing method, the radix yield (kg/10a) was increasing every cultivated year. However, the difference of radix yield at four and five-years-old peony were not significant. The radix yield of four-years-old peony was higher 26% than three-years-old one. As cultivated year goes by, content of paeoniflorin was increasing then the content was highest at four-years-old peony (4.06%). In 1995, the content, had no certain tendency, was highest at three-years-old peony (3.14%). At hot air drying, browing of peony radix was increasing every cultivated year. If we consider radix yield and color, three-years-old peony was proper object of harvesting.