A Comparative SEM Investigation of Smear Layer Remaining on Dentinal Walls by Three Rotary NiTi Files with Different Cross Sectional Designs in Moderately Curved Canals

Comparison of Cleaning Efficiency of Root Canal Using Different Rotary NiTi Instrumentation System: A Scanning Electron Microscopic Study

Background: To ensure that endodontic treatment is as effective as possible, it is important to remove any smear layer that forms as part of the instrumentation procedure. This layer might reduce the overall effectiveness of endodontic therapy.

Aim of the study: For this research, two distinct types of rotary NiTi files were compared: WaveOne Gold (WOG) (Dentsply Maillefer, Ballaigues, Switzerland) and F360 (Komet Brasseler GmbH & Co., Lemgo, Germany) for its capacity to eliminate trash and the smear layer.

Materials and methods: Two groups (n=20 each) of 40 mandibular second premolar teeth were employed in this investigation, with each group receiving a random allocation of teeth. The F360 system and the WaveOne Gold system are two sets of instruments. The samples were irrigated with a mixture of sodium hypochlorite (NaOCl) (5.25%) and citric acid (40%). Finally, all samples in the centre of the coronal, middle, and apical thirds were examined by scanning electron microscopy (SEM). Mann-Whitney U tests were used to analyse the data.

Results: F360 instrument showed a statistically significant difference for smear layer removal among all thirds of the root canal whereas WOG resulted in a significant difference when the apical third was compared to the middle and coronal third. Significant differences were found in the middle and apical third in terms of smear layer removal between the two groups.

Both F360 and WOG instruments showed statistically significant differences for debris removal among all thirds of the root canal. No significant differences were found in the coronal, middle, and apical third in terms of debris removal between the two groups.

Conclusion: WOG resulted in cleaner canals compared to the F360 file system at coronal, middle, and apical third.

In vitro effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls

BACKGROUND

A successful endodontic treatment depends on efficient cleaning and shaping and effective irrigation of root canals. The irrigating solution may not be effective in some areas in the canal. The manufacturer of XP-Endo finisher claims that it can effectively clean the root canals with complex morphology. This study aimed to assess the effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls of mandibular second premolars.

MATERIALS AND METHODS

In this In vitro study Fifty extracted mandibular second premolars with a root curvature <20° were collected. Root canals were prepared using BioRaCe rotary system. The root canals were in contact with the file and different irrigating solutions for 1 min. The teeth were then randomly divided into four experimental (n = 10) and one positive control group as follows: (1) XPF + saline, (2) XPF + ethylenediaminetetraacetic acid (EDTA), (3) XPF + sodium hypochlorite (NaOCl), (4) XPF + EDTA + NaOCl and (control) EDTA + NaOCl. The teeth were longitudinally sectioned into two halves and the amount of debris and smear layer remaining in the coronal, middle, and apical thirds of the roots was quantified and scored under an electron microscope. The Kruskal-Wallis test was used to compare the groups, and P < 0.05 was considered statistically significant.

RESULTS

The highest mean amount of residual debris (2.9 ± 1.13) was noted in XPF + saline group (P < 0.05). XPF + saline and XPF + NaOCl (3.8 ± 0.60) had the lowest efficacy for smear layer removal (P < 0.05) with no significant within-group difference. No significant difference was noted between Groups 2, 3, and 4 with the positive control group regarding debris removal. Groups 2 and 4 had no significant difference with the positive control group regarding smear layer removal.

CONCLUSION

Use of XP-Endo finisher has no superiority to the standard protocol for the use of irrigating solutions (EDTA + NaOCl) for debris and smear layer removal, but in some cases, such as second appointment of regeneration treatment we cannot use NaOCl because of its destructive effects on stem cells; thus, we can benefit from the synergistic effects of XPF and EDTA for better smear layer removal.

Comparative Evaluation of Cleaning Efficacy using Four Novel Nickel-titanium Rotary Instruments: An in vitro Scanning Electron Microscope Study

AIM

The aim of the study was to compare the cleaning efficacy (debris and smear layer removal) of two multifile rotary systems (MTwo and Silk) and two single-file rotary systems (F6 Skytaper and NeoNiTi).

MATERIALS AND METHODS

Eighty mesial canals of mandibular first molars were cleaned and shaped using four nickel-titanium (NiTi) rotary instruments to size # 25 and 3% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA). Samples were randomly divided into four equal groups (n = 20) according to instrumentation: Group I, Mtwo; group II, Silk; group III, F6 Skytaper; group IV, NeoNiTi. Samples were split longitudinally and examined under scanning electron microscope (SEM) for debris and smear layer removal in coronal, middle, and apical thirds of each root canal.

RESULTS

F6 skytaper and Mtwo groups showed significantly higher debris removal than Silk and NeoNiTi groups in apical third of root canal as well as when compared with NeoNiTi group in middle third. F6 Skytaper group showed significantly higher debris and smear layer removal than Silk group in coronal third. There was statistically significant difference among all thirds of root canal in terms of debris removal in Silk and NeoNiTi groups. There was statistically significant difference among all thirds of root canal in F6 Skytaper and NeoNiTi groups in terms of smear layer removal.

CONCLUSION

F6 Skytaper single-file rotary instrumentation showed the maximum cleaning efficacy followed by Mtwo multifile rotary instrumentation in all thirds of root canal.

CLINICAL SIGNIFICANCE

F6 Skytaper rotary instrument is most efficient followed by Mtwo rotary instrument among all rotary instruments.

Scanning Electron Microscopic Evaluation of Smear Layer Removal Using Isolated or Interweaving EDTA with Sodium Hypochlorite

Introduction:

The aim of this study was to verify the effect of alternating 2.5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) on the smear layer removal from root canal surfaces.

Methods and Materials:

A total of 15 single-rooted human teeth, instrumented with ProTaper files, were randomly distributed in 3 groups. In group 1 (n=7) the canals were irrigated with 1 mL of 2.5% NaOCl between files and final irrigation was done with 1 mL of 2,5% NaOCl, followe by 1 mL of 17% EDTA, for a perio of 15 sec with new irrigtion of 1 mL of 2,5% NaOCl at each change of files. In group 3 (control group) (n=1), saline solution was used. All samples were cleaved into two sections, metalized and analyzed under scanning electron microscopy (SEM). The presence or absence of smear layer in the cervical, middle and apical thirds, with scores varying from 1 to 3, respectively were evaluated. The data were submitted to nonparametric Mann-Whitney U test. The level of significance was set at 0.05.

Results:

It was observed that there was a greater discrepancy between groups with respect to the apical third. In the other areas there was a greater similarity between the scores attributed to the groups. There was a statistically significant difference between the groups only in the apical third, when group 1 presented the higher median (P<0.05).

Conclusion:

The alternating use of EDTA during instrumentation with NaOCl was the most effective irrigation method to remove the apical smear layer. Both forms of irrigation were effective on removal of the smear layer in the coronal and middle thirds of the canals.

Nail Damage (Severe Onychodystrophy) Induced by Acrylate Glue: Scanning Electron Microscopy and Energy Dispersive X-Ray Investigations

BACKGROUND

Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques have been used in various fields of medical research, including different pathologies of the nails; however, no studies have focused on obtaining high-resolution microscopic images and elemental analysis of disorders caused by synthetic nails and acrylic adhesives.

METHODS

Damaged/injured fingernails caused by the use of acrylate glue and synthetic nails were investigated using SEM and EDX methods.

RESULTS

SEM and EDX proved that synthetic nails, acrylic glue, and nails damaged by contact with acrylate glue have a different morphology and different composition compared to healthy human nails.

CONCLUSIONS

SEM and EDX analysis can give useful information about the aspects of topography (surface sample), morphology (shape and size), hardness or reflectivity, and the elemental composition of nails.