Comparative evaluation of 15% ethylenediamine tetra-acetic acid plus cetavlon and 5% chlorine dioxide in removal of smear layer: A scanning electron microscope study

Comparison of Different Dentin Deproteinizing Agents on Bond Strength and Microleakage of Universal Adhesive to Dentin

Aim:

To evaluate the effects of papain (Brix 3000), bromelain, sodium hypochlorite (NaOCl), and chlorine dioxide (ClO2) application to the deep dentin surface on shear bond strength (SBS), microleakage, and dentin surface properties.

Materials and Methods:

Deep dentin surface ( n = 100) for evaluating SBS, class V preparation at the buccal surface for testing microleakage ( n = 100), and deep dentin slices ( n = 20) for evaluating surface properties were conducted on the 220 molar teeth. Four different deproteinizing agents (Brix 3000, 40% bromelain, 5.25% NaOCl (Chloraxid), and 0.12% ClO2) were applied to the dentin, and then the universal adhesive was used in self-etch (SE) and etch&rinse (E&R). Deproteinizing agents were not applied to the control group. All of the samples were subjected to 5000 cycles of thermal aging at 5ºC–55ºC. SBS (MPa) was tested by a universal testing machine. The microleakage of resin composite bonded with different adhesive modes was evaluated under a stereomicroscope. The changes in the surface morphology were examined with scanning electron microscopy (SEM) and attenuated total reflection – fourier transform infrared spectroscopy (ATR-FTIR).

Results:

ClO2 exhibited the highest bond strength among deproteinizing agents. Compared to the SE mode, E&R mode significantly showed higher bond strength ( p < .05). In gingival margin, bromelain SE exhibited the highest marginal leakage, while Brix 3000 SE had the lowest mean microleakage score.

Conclusion:

Deproteinizing with ClO2 was effective in improving the SBS of universal adhesive in the E&R mode to deep dentin. Deproteinization with bromelain before universal adhesive in SE mode showed more microleakage on both the occlusal and gingival surfaces.

Evaluation of the Antibacterial Effects of Single and Combined use of Different Irrigation Solutions Against Intracanal Enterococcus Faecalis

Objectives

This study assessed the antibacterial activity of both separate and combined uses of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% ethylenediaminetetraacetic acid (EDTA), 3% hydrogen peroxide (H₂O₂), MTAD, SmearClear (SC) and 13.8% chlorine dioxide (ClO₂) irrigation solutions against Enterococcus faecalis.

Materials and Methods

Two hundred eighty single rooted human premolars were randomly grouped into 26 test and 2 control (negative and positive) groups and were incubated for 24 h with E. faecalis, except for the negative control group. The tested solutions were as follow: NaOCl; CHX; ClO₂; MTAD; SC; EDTA; H₂O₂; NaOCl + CHX; NaOCl + MTAD; SC + NaOCl; EDTA + NaOCl; H₂O₂ + NaOCl; ClO₂ + CHX; CHX + MTAD; SC + CHX; EDTA + CHX; CHX + H₂O₂; ClO₂ + MTAD; SC + ClO₂; EDTA + ClO₂; ClO_{2 +} H₂O₂; SC+MTAD; EDTA+MTAD; MTAD + H₂O₂; SC + H₂O_2; and EDTA + H₂O_2. Optic density values were recorded at 0, 6, 12, 18, 24, 30, 36, 42 and 48 h and bacterial growth curve created for each solution.

Results

The CHX, MTAD and ClO₂ showed a high potential for the elimination of E. faecalis, both alone and in all combinations. The EDTA, H₂O₂, H₂O₂+ EDTA, H₂O₂ + NaOCl and SC + NaOCl groups showed less antibacterial activity than the other groups. The SC + CHX group showed the best antibacterial effect against E. faecalis.

Conclusion

The SC + CHX combination can be recommended as the most effective irrigation regimen against E. faecalis in persistent endodontic infections.

Effect of 5% Chlorine Dioxide Irrigant on Micro Push Out Bond Strength of Resin Sealer to Radicular Dentin: An In Vitro Study

INTRODUCTION

Chlorine dioxide (ClO₂) has been recently investigated as a possible root canal irrigant due to its broad spectrum of antimicrobial action, tissue dissolution and smear layer removal properties. Literature is scarce on the effect of chlorine dioxide irrigation on the resin sealer dentin bond strength.

AIM

To compare 5% chlorine dioxide (ClO₂) with or without Ethylene Diamine Tetra Acetic acid (EDTA) with 3% Sodium hypochlorite (NaOCl) and EDTA combination as endodontic irrigants on the adhesion of AH Plus sealer to radicular dentin using micro- Push out Bond Strength (µPBS) test.

MATERIALS AND METHODS

Forty freshly extracted central incisors were decoronated and randomly divided into four groups based on the different irrigation regimes followed during irrigation: Group I - 3% NaOCl + 17% EDTA, Group II - 5% ClO₂ + 17% EDTA, Group III - 5% ClO₂ and Group IV - Saline, and canal enlarged till Protaper F3. All the samples were obturated with F3 gutta-percha cones using AH Plus sealer and sectioned perpendicular to long axis to obtain 1mm thick slices from the middle and coronal portions for µPBS measurement in universal testing machine followed by assessment of failure pattern under stereomicroscope. Data was analysed using One-way analysis of variance (ANOVA), Bonferroni and t-test.

RESULTS

Bond strength values were in the following order: Group I>Group II>Group III>Group IV, with no statistically significant difference amongst experimental groups on intergroup comparison, except with saline. The µPBS values were more in coronal third than middle third in all specimens, with no statistical significant difference. Mode of failure showed mixed patterns in all experimental groups except saline.

CONCLUSION

In the present study, the bond strength values of ClO₂ were comparable with conventional NaOCl and EDTA combination and hence, ClO₂ can be considered as an effective alternative endodontic irrigant.