To Evaluate the Efficacy of an Innovative Irrigant on Smear Layer Removal - SEM Analysis

Cytotoxicity and Efficacy in Debris and Smear Layer Removal of HOCl-Based Irrigating Solution: An In Vitro Study

In the present study we evaluated the cytotoxicity of super-oxidized water on human gingival fibroblasts and its efficacy in debris and smear layer removal from root canal walls. Cultured gingival fibroblasts were exposed to super-oxidized water (Sterilox), which was diluted in Iscove’s modified Dulbecco’s medium (IMDM) at 30%, 40%, 50%, 60% and 70% concentrations. The control group was maintained in IMDM. The cell viability was evaluated by means of an MTT assay after incubation periods of 1 h, 2 h, 24 h and 48 h. Pathological cellular changes were also observed under fluorescence and phase contrast microscopes. The efficacy in debris and smear layer removal was evaluated in comparison to the conventional application of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). Forty maxillary premolars were randomly divided into two equal groups (n = 20) and shaped with ProTaper NEXT rotary instruments using Sterilox or NaOCl/EDTA for irrigation. Afterwards, roots were split longitudinally and examined under a scanning electron microscope. The results revealed that super-oxidized water and sterile distilled water have acceptable biological properties for endodontic applications at concentrations up to 50% (p > 0.05). Moreover, super-oxidized water is equally effective in debris and smear layer removal as compared to NaOCl/EDTA (p > 0.05).

The Effect of Photodynamic Therapy on the Smear Layer Removal: a Scanning Electron Microscopic Study

Statement of the Problem

The efficacy of photodynamic therapy (PDT) in smear layer removal compared to the currently accepted protocol is not well established.

Purpose

This study aims to evaluate the effect of PDT on smear layer removal from human root canal compared to combined use of irrigation solutions including sodium hypochlorite (NaOCl) and ethylene diamine tetra acetic acid (EDTA) by scanning electron microscopy (SEM).

Materials and Method

In this in vitro study, straight roots from 48 extracted human maxillary incisors and canines were selected and decoronated. Instrumentation was completed with RaCe rotary system and normal saline irrigation between files. Then roots were randomly divided into 3 groups (n=16). Group 1 was the control group to confirm smear layer formation. In the group 2, the canals were irrigated with 2ml of 2.5% NaOCl solution for 10 minutes and 2ml of 17% EDTA solution for 1 minute. In the group 3, PDT with methylene blue and diode laser (625nm, 150mW, for 5minutes) was the final procedure for smear layer removal. All the specimens were sectioned into two halves, gold coated, and analyzed under SEM. The smear layer in the coronal, middle, and apical thirds, were evaluated and scored by two examiners independently. Statistical analysis was done using Chi-square test.

Results

It was observed that the NaOCl+EDTA removed the smear layer significantly better than PDT in the coronal and apical thirds (p< 0.05) whereas PDT was unable to remove the smear layer in none of the root areas. At the apical thirds, there was no significant difference between NaOCl+EDTA and PDT (p< 0.05). Both procedures were unable to remove smear layer from radicular dentine of this area.

Conclusion

According to the results of this in vitro study, the use of PDT alone is not recommended to remove smear layer. The combined application of NaOCl and EDTA is ineffective in removing smear layer of apical third, despite its efficacy on the coronal and middle regions.

Effect of ultrasonic activation on calcium ion quantification, smear layer removal, and canal cleaning efficacy of demineralizing irrigants

Background

Effective removal of smear layer ensures better penetration of irrigants ensuring root canal disinfection and has the potential of sealing dentinal tubules during obturation.

Aim

The aim of this study is to evaluate the canal cleaning efficacy and calcium ion liberation with the use of demineralizing irrigants, namely, 17% ethylenediaminetetraacetic acid (EDTA), 7% maleic acid, and 10% citric acid with or without ultrasonic (US) activation.

Materials and Methods

Crowns of 62 extracted maxillary central incisors were decoronated and root canals prepared. Based on the final irrigant teeth were divided into following groups (n = 10), namely, 10% citric acid, 7% maleic acid, 17% EDTA, and 10% citric acid with US activation, 7% maleic acid with US activation, and 17% EDTA with US activation. Irrigants were subjected to inductively coupled plasma-atomic emission spectroscopy followed by debris scoring and scanning electron microscope analysis.

Statistical Analysis

One-way analysis of variance with the Bonferroni's correction for multiple testing was employed.

Results

About 10% citric acid with US activation liberated the highest calcium ions and removed the maximum smear layer.

Conclusions

Citric acid with US activation is a potentially effective irrigation regimen with sodium hypochlorite.

Comparative analysis of endodontic smear layer removal efficacy of 17% ethylenediaminetetraacetic acid, 7% maleic acid, and 2% chlorhexidine using scanning electron microscope: An in vitro study

Aim:

The aim of the present study was to evaluate the efficiency of different endodontic irrigants in the removal of smear layer through scanning electron microscopic image analysis.

Materials and Methods:

The present in vitro study was carried out on 45 single-rooted extracted human mandibular premolar teeth with single canal and complete root formation. Teeth were randomly assigned to three groups with 15 teeth in each group. Group I samples were irrigated with 17% ethylenediaminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group III with 2% chlorhexidine irrigation. Scanning electron microscope evaluation was done for the assessment of smear layer removal in the coronal, middle, and apical thirds. Comparison of the smear layer removal between the three different groups was done by Kruskal–Wallis test, followed by Mann–Whitney U test for comparing individual groups. A P value less than 0.05 was considered to be statistically significant.

Results:

Statistically significant difference was seen between the two test groups (17% EDTA vs. 7% maleic acid and 17% EDTA vs. 2% chlorhexidine) in smear layer removal at coronal, middle, and apical thirds of the root canal. The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation compared with other groups (P < 0.05) and the least by 2% chlorhexidine.

Conclusion:

The present study shows that 17% EDTA efficiently removes the smear layer from root canal walls.