Removal patterns of smear layer according to application temperature and time of EDTA.
10.5395/JKACD.2002.27.5.535
- Author:
Jang Shik SHIN
1
;
Yong Bum CHO
Author Information
1. Department of Conservative Dentistry College of Dentistry, Dankook University, Korea.
- Publication Type:Original Article
- MeSH:
Awards and Prizes;
Calcium Hydroxide;
Dental Pulp Cavity;
Edetic Acid;
Humans;
Microscopy, Electron, Scanning;
Smear Layer;
Sodium Hypochlorite;
Tooth
- From:Journal of Korean Academy of Conservative Dentistry
2002;27(5):535-542
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
The purpose of this study was to evaluate the effect of EDTA irrigant according to application time and temperature. 31 human mature extracted teeth with a single canal were sectioned with microtome in 3mm thickness and gained 62 samples of root canals. They were distributed randomly into 6 groups of 10 specimens each and control group of 2 specimens. Each specimen was prepared with GT rotary file (Dentsply, Maillefer Co., Swiss) and irrigated with 3 ml sodium hypochlorite every minute. Then smear layer was removed with EDTA solution (PULPDENT(R), PULPDENT Co., USA.) except two control specimens. Specimens of each group were irrigated with 17% EDTA. All specimens were split longitudinally and prepared for examination by scanning electron microscopy. A set of reference micrographs was used to award a debris score as follows: 0 = no smear layer, all tubules clean and open; 1 = no superficial smear layer, tubule openings visible, but some contain debris plug or soft tissue remnants; 2 = moderate smear layer, some tubules open and others closed; 3 = heavy smear layer, most/all tubule openings obscured. Results were evaluated with Kruskal-Wallis test to determine whether there was statistically significant difference among six groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Mann-Whitney test. The results were as follows: 1. Control specimens showed heavy smear layer at the canal walls. 2. Among the groups applied with EDTA for 2 minutes, group 1 showed the heaviest smear layer, and there was statistically significant difference between group 1 and the other groups(p<0.05). 3. Among the groups applied with EDTA for 5 minutes, group 4 and group 6 showed smear layer, but there was no significant difference between them. 4. Among the groups applied with EDTA for the same temperature, group 1 showed heavier smear layer than group 4, and there was statistically significant difference(p<0.05). 5. Among the groups applied with EDTA for the same temperature, group 2 showed heavier smear layer than group 5 and group 3 showed heavier smear layer than group 6. But there was no statistically significant difference among them. From the results above, it could be concluded, EDTA solution is effective in removing of smear layer when it is applied for 5 minutes. If EDTA is applied for 2 minutes, it should be applied above room temperature.
