• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.169-178
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• 2006

This study was to verify that the combined application of NaOCl and EDTA was more effective in removal of smear layer than the application of NaOCl alone. furthermore it was aimed to find out the optimal time for the application of EDTA. Thirty five single rooted teeth were cleaned and shaped. NaOCl solution was used as an irrigant during instrumentation. After instrumentation, root canals of the control group were irrigated with 5 ml of NaOCl for 2 minutes. 30 sec, 1 min, and 2 min group were irrigated with 5 ml of 17% EDTA for 30 sec, 1 min, and 2 min respectively. Then the roots were examined with scanning electron microscopy for evaluating removal of smear layer and erosion of dentinal tubule. The results were as follows; 1. The control group: The smear layer was not removed at all. 2. The other groups: 1) $Middle\frac{1}{3}$: All groups showed almost no smear layer. And the erosion occurred more frequently as increasing irrigation time. 2) $Apical\frac{1}{3}$: The cleaning effect of 2 min group was better than the others. The results suggest that 2 min application of 17% EDTA should be adequate to remove smear layer on both $apical\frac{1}{3}\;and\;middle\frac{1}{3}$.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.477-486
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• 1998

Recently the development of rotary instrument makes it possible that in root canal treatment operator saves much more time, maintans original curved canal shape and easily prepares continuous tapered root canal. The purpose of this experiment was to examine the smoothness of the internal surface of prepared root canal and the effectiveness of debridement in prepared root canal by SEM for the comparison of hand and Ni-Ti rotary instrument. 25 extracted human teeth were access opened and # 10 K-type file was introduced into canal until it was appeared at the apical foramen. The working length was established by subtracting 0.5mm from this measurement. Group 1. The root canal preparation was done to # 30 with working length and then step-back until # 45 with K-Flexofile (Maillefer, Swiss). Group 2. Root canal preparation was done by Naviflex Ni-Ti file (Brasseler, USA) as the same technique with group 1. Group 3. Canal was prepared by Profile .04 (Maillefer, Swiss) taper until #30. Group 4. With use of Quantec (Tycom, USA) root canal was prepared from file number 1 to 8. In group 1 and 2, the root canal irrigant was NaOCl and the other groups, NaOCl and RC-prep (Premine Dental Products, USA) was used. The prepared teeth were notched with high-speed bur as bucco-lingual direction and fractured with chisel and mallet, then examined with SEM. Group 1 showed smooth internal surface. There were scratches mainly to the axial direction. Group 2 showed similar characteristics to those in group 1. Group 3 showed more smoother and linear cutting surface with bised scratches. Group 4 has the almost same characteristics group 3 and there was no difference in the file design. Ni-Ti rotary root canal instrument prepare the dentinal wall more smoother than hand instrument. The effectiveness of debridement was not fully affected by file design. The isthmus area and accessory canals of the root canal system were not prepared in any group. According to the result, hand and rotary type instrumentation techniques were effective in removal of major amount of tissue from root canal but it was not complete. In the direction of cutting movement there was difference between them.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.168-178
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• 2010

Objective : The aim of this study was to determine the antimicrobical effect of horseradish root extracts against Enterococcus faecalis and Fusobacterium nucleatum isolated from oral cavity compared with reference strain, and compared with that of chlorhexidine. Method : Horseradish root extracts and chlorhexidine were sequentially diluted and tested against anaerobes(E. faecalis, F. nucleatum) isolated from children's oral cavity. The microbes were anaerobically incubated and the minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) were detected. Results :1. Horseradish root extracts showed antimicrobial effect against E. faecalis isolated strain at same or slightly higher concentration compared with MIC of reference strain. 2. $625.0\sim1,250.0{\mu}g/ml$ horseradish root extracts showed similar antimicrobial effect with chlorhexidine($7.8\sim15.6{\mu}g/ml$). 3. Horseradish root extracts showed antimicrobial effect against F. nucleatum isolated strain at same or slightly higher concentration compared with MIC of reference strain. 4. $78.1\sim312.5{\mu}g/ml$ horseradish root extracts showed similar antimicrobial effect with chlorhexidine($7.8\sim15.6{\mu}g/ml$). Conclusions : The results of this study confirm that horseradish root extracts has antimicrobial effect against anaerobes isolated from oral cavity as well as reference strain. And we found the potential of horseradish root extracts as a canal irrigant or disinfectant.