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법랑질(琺瑯質)과 상아질(象牙質)의 산처리후(酸處理後)의 전자현미경(電子顯微鏡) 소견(所見)에 관(關)한 연구(硏究)
김영해,Kim, Yung-Hai 대한치과보존학회 1983 Restorative Dentistry & Endodontics Vol.9 No.1
The purpose of this study was to compare the solubility of enamel and dentin to an etchant after fluoride application. Specimens were collected from extracted anterior and bicuspid and each tooth was cut into several pieces. These specimen were allocated in 7 group; 1%, 2%, 3% NaF, 1%, 8%, 20% $SnF_2$, and control group. Five specimens in each group was exposed to pre-determined fluoride solution for 3 minutes, and washed with running water. These specimens were etched by Hipol (commercial label) etchant for 30 seconds. Following are the findings obtained through S.E.M. 1. All specimens with acid etching revealed preferential removal of prism periphery leaving prism core. 2. Specimens treated with 1%, 2% NaF solution showed that the shape of prism tip was thin and sharp like a needle. The case of 3% NaF showed rather round shape at prism end. 3.1% of $SnF_2$ case showed similar findings with the control group but 8% and 20% $SnF_2$ case revealed needle shape at the prism and was less clear than NaF case. Preferential removal of prism periphery was partialy observed and un decalcified area is fused to prism forming reidge. 4. Dentine treated by fluoride compound in low concentration showed the orifice of dentinal tubule was clearly enlarged whereas in high concentration the orifice was not widened.
불소화합물(弗素化合物)이 법랑질탈회(琺瑯質脫灰)에 미치는 영향(影響)에 관(關)한 연구(硏究)
김영해,Kim, Yung-Hai 대한치과보존학회 1988 Restorative Dentistry & Endodontics Vol.13 No.1
The purpose of the study was to confirm the influence of fluoride to enamel decalcification. Specimens were prepared from 20 extracted teeth. Every tooth was sliced into 4 pieces by means of seperating disc. The pieces with sound enamel were distributed to 4 groups. 1st group was treated with 0.5% NaF solution for 2 minutes. 2nd group was treated with 0.5% NaF solution for 10 minutes. 3rd group was treated with 1% NaF solution for 2 minutes. 4th group was treated with 1% NaP solution for 10 minutes. The enamel surface of each specimen were decalcified with 30% $H_3PO_4$ for 2 minutes and the findings through electron microscope were as follows; 1. The degree of decalcification on the 1st group was greater than that of the 2nd group. 2. Roughness of the 3rd group was slightly higher than that of the 4th group. 3. Under the same procedure of decalcification, the specimen treated by higher conceutration of NaF solution for same length of time showed less decalcified picture. 4. Under the same procedure, of decalcification, the specimens treated by same concentration of NaF solution for different length of time, were compared and found longer the time less decalcified.
동합금(銅合金)의 조직상(組織像)에 관(關)한 연구(硏究)
김영해,Kim, Yung-Hai 대한치과보존학회 1978 Restorative Dentistry & Endodontics Vol.4 No.1
Brass specimen, copper based alloy was prepared in cubic form about $1cm{\times}1cm{\times}1cm$ in volume. The specimens were mechanically compressed in one direction until the dimension distorted to 20%, 40%, 60% and 80% in length. The compressed specimens with 80% distorted in length were then heat treated in $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$ for 30 minutes. Microscopic examination was made on both compressed and heat treated specimens. The results obtained from the study were as follows: 1. Grain boundary and twin phenomenon was clearly seen in 0% and 20% compressed cases. Slip bands was appeared in 40% cases and distributed equally as well as twin. 2. The first evidence of slip bands was observed in 20% and the bands grew thicker and denser as the compression increased. 3. The density of the bands were reduced after annealing in $200^{\circ}C$ and completely disappeared at $300^{\circ}C$ cases. 4. Recrystallization was noticed unevenly in $300^{\circ}C$ cases and the evidence of twin was observed in these crystallized area. 5. In $400^{\circ}C$ cases the grain boundary was evenly found and the twin phenomenon was clearly observed. Grain boundary and twin was noticeably formed in size according to the annealing temperature increased.
근관치료약제(根館治療藥濟)의 살균효과(殺菌效果)에 관(關)한 연구(硏究)
김영해,Kim, Yung-Hai 대한치과보존학회 1985 Restorative Dentistry & Endodontics Vol.11 No.1
Coccal form of microorganism (staphylococcus) isolated from infected root canal was inoculated on the thioglycolate agar and paper discs (5mm in diameter) immersed with 0.1ml of 10% Formaldehyde, Thymol, Eugenol Phenol (90%) and 5% Silver nitrate were placed on the media. The thioglycolate plate was incubated at $37^{\circ}C$ for 48 hours. Inhibition zone was measured as follow: The greatest value was 3.9mm at Formaldehyde, next followed Thymol 3.6mm, Eugenol 3.5mm and Phenol 3.4mm. The least value, 3.0mm was found at Silver nitrate.