A comparison of the effects of three chelating agents on the root canals of extracted human teeth

Scanning electron microscopic evaluation of the efficacy of 5% ethylenediaminetetraacetic acid for smear layer removal

The purpose of the study was to evaluate the smear layer removal efficacy of novel Saver® irrigating solution including 5% EDTA and to compare the 17% EDTA as the most used counterpart. Forty-four single-rooted teeth were divided into four groups, were instrumented, and irrigated. The smear treatment groups were as follows: sterile distilled water; 5.25% sodium hypochlorite; Saver®; 17% EDTA. The root samples were blinded. The micrographic images of root samples were collected by scanning electron microscope. The percentages of open dentin tubules were quantified using an image analysis software on micrographs. Two-way ANOVA followed by Tukey's multiple comparisons was used (p < .05). The 17% EDTA showed the highest percentages of open dentin tubules than the other treatments (p < .01). The mean percentages of open dentin tubules of 17% EDTA revealed statistically highly significant differences than Saver® treatment in all root regions (p < .01). Dentin tubules were covered by dense smear layer in distilled water irrigation whereas, the tubular pattern of dentin structure was not observed in hypochlorite irrigation. The commercial Saver® product presented to be less cleaning property on the smear layer than 17% EDTA and failed to show any improvement in the removal of smear layer compared with its tested counterpart.

Comparative evaluation of efficacy of ethylenediaminetetraacetic acid, maleic acid, and dimercaptosuccinic acid against the combination of these with sodium hypochlorite for removal of smear layer: An in vitro scanning electron microscope study

Context:

The effect of dimercaptosuccinic acid (DMSA) and maleic acid (MA) when used alone on smear layer has been evaluated with mixed results, but their effect when combined with sodium hypochlorite (NaOCl) has not been studied.

Aim:

To compare the effectiveness of ethylenediaminetetraacetic acid, MA, and DMSA against the combination of these with NaOCl in the removal of smear layer.

Settings and Design:

n = 4pq/L²

q = 1 − p

p = Incident rate

L = Allowable error

Methods:

One hundred and forty extracted, anterior teeth were radiovisiographically assessed. Access preparation was done; apical patency was established. Cleaning and shaping was accomplished using step-back technique. The specimens were randomly allocated as per the final irrigation protocol. After final irrigation, teeth were prepared for scanning electron microscope analysis, and the middle and apical thirds of radicular dentin were evaluated at ×1000 for evaluation of severity of occlusion of dentinal tubules with smear layer.

Statistical Analysis:

The data were statistically analyzed using the Student's t-test and kappa test.

Results:

For combined irrigation, 10% DMSA + NaOCl was significantly better than all other groups both in the middle third and the apical third. It was more effective in the middle third than at apical third.

Conclusion:

Ten percent DMSA in combination with NaOCl removes the smear layer more effectively at both the middle and apical third.

Interaction between EDTA and sodium hypochlorite: a nuclear magnetic resonance analysis

Recent studies detected erosion of the dentinal walls following the use of EDTA as a final flush. Several authors have studied degradation of EDTA and it appears to be caused by an oxidation reaction. The objective of this paper was to verify through nuclear magnetic resonance (NMR) analysis if the oxidizing property of sodium hypochlorite inactivates EDTA. Solutions of sodium hypochlorite and EDTA were analyzed. EDTA tracing and the appearance of new signals indicative of by-products of the reaction, were studied at different time intervals with a NMR analysis. The tracings of NMR analysis confirmed that the reaction between sodium hypochlorite and EDTA lead to a very slow but progressive degradation of this compound. Mindful of the limitations of an in vitro study, the results of this study nevertheless demonstrated that a final flush with sodium hypochlorite cannot limit the chelating effects of EDTA in a clinically realistic time period.

Effect of three different time periods of irrigation with EDTA-T, EDTA, and citric acid on smear layer removal

OBJECTIVE

An in vitro study was conducted to evaluate the effect of EDTA-T, 17% EDTA, and 10% citric acid on the removal of smear layer from root canal dentin after final irrigation for 3, 10, and 15 min.

STUDY DESIGN

Root canals of 90 extracted human canines were divided into 9 groups of 10 teeth; each group received a final irrigation with one of the irrigants for the established time intervals. After irrigation, the teeth were split and prepared for SEM analysis to determine the number of open dentinal tubules.

RESULTS

There were statistically significant better results (P <.05) when irrigation with 10% citric acid for 3 min was compared to 10 and 15 min, and when irrigation with EDTA for 3 min was compared to 15 min. In all cases, irrigation for 3 min presented the greatest number of open dentinal tubules. There were no significant differences (P>.05) for the 3 time intervals of irrigation for EDTA-T, although there were a greater number of open tubules at 3 min.

CONCLUSION

These 3 irrigants were effective at the shortest time tested and did not demonstrate an improved effect with an increase in time.

Chelating agents in root canal treatment: mode of action and indications for their use

Chelating agents were introduced into endodontics as an aid for the preparation of narrow and calcified root canals in 1957 by Nygaard-Østby. A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal dentine and dissolve the smear layer, as well as to increase dentine permeability. Although the efficacy of EDTA preparations in softening root dentine has been debated, chelator preparations have regained popularity recently. Almost all manufacturers of nickel-titanium instruments recommend their use as a lubricant during rotary root canal preparation. Additionally, a final irrigation of the root canal with 15-17% EDTA solutions to dissolve the smear layer is recommended in many textbooks. This paper reviews the relevant literature on chelating agents, presents an overview of the chemical and pharmacological properties of EDTA preparations and makes recommendations for their clinical use.

Comparative in-vitro evaluation of three chelator pastes

AIM

To compare the effect of three paste chelating agents on the root dentine of extracted teeth: Calcinase-Slide (lege artis, Dettenhausen, Germany), Glyde-File (DeTrey/Dentsply, Konstanz, Germany), RC-Prep (Premier, Norristown, USA).

METHODOLOGY

Ten slices of root dentine were covered with one of the chelating agents for 30 s, 1 min and 2 min and irrigated with 5 mL H2O2 and NaOCl. This was repeated five times. Pre- and postoperative Vickers hardness of root dentine was measured. Twenty slices of root dentine were covered with 0.1 mL of the chelating agents for 3, 6 and 9 min. Differences between pre- and postoperative weight were recorded. Ten root canals of extracted teeth were enlarged five ISO-sizes with 0.1 mL chelator paste for each file. The teeth were split longitudinally and cleanliness of the root-canal walls was evaluated under the SEM using a four-score evaluation index. Results were statistically analysed using the Wilcoxon-Mann-Whitney test, the Friedman test and the Kruskal-Wallis test with P<0.05 for all tests.

RESULTS

No significant differences between the chelating agents were found in terms of changes in dentine hardness. Loss of hardness increased significantly with increasing time of contact of the chelating pastes with dentine. There were significant differences between the three chelating agents and the control for loss of weight. After 3 min there was no significant difference between the chelating agents, after 6 and 9 min Calcinase-Slide showed significantly more weight loss than RC-Prep; after 6 min Glyde-File showed significantly more weight loss than RC-Prep. In the coronal and middle parts of the root canals, the cleaning ability of Calcinase-Slide was significantly better than of RC-Prep and Glyde-File; in the apical third no differences could be found.

CONCLUSIONS

Under the circumstances of this in vitro study, the three chelator pastes evaluated had no or only slight differences in terms of weight loss, changes of Vickers hardness in root dentine and cleanliness of root-canal walls. The use of a chelating agent may be useful to enhance cleanliness of the coronal and middle part of the root canal.