Comparative evaluation of human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite: An in vitro study

Comparative evaluation of antifungal activity of Sodium Hypochlorite, Calcium Hypochlorite and modified Salt Solution associated with passive ultrasonic irrigation against Candida albicans - An In-Vitro study

Aim

The study evaluated the antifungal activity of sodium hypochlorite (NaOCl), calcium hypochlorite (Ca(OCl)2), and modified salt solution (MSS) assisted with passive ultrasonic irrigation against Candida albicans.

Materials and Methods

One hundred and thirty-six single-rooted premolars were decoronated and enlarged up to a file #45, autoclaved, inoculated with C. albicans, and incubated for 72 h. The samples were randomly distributed into eight groups (n = 17) according to the protocol for decontamination G1: No treatment, G2: Distilled water (DW), G3: 2.5% NaOCl, G4: 2.5% NaOCl + ultrasonic activation (US), G5: 2.5% Ca(OCl)2, G6: 2.5% Ca(OCl)2 + US, G7: MSS, G8: MSS + US. Microbiological testing (Colony forming Unit [CFU] counting) was performed before and after the treatment.

Statistical Analysis

Data were subjected to the one-way analysis of variance followed by the Tukey's post hoc test (P < 0.05).

Results and Conclusion

Groups 1 and 2 showed the highest mean contamination (5.41 and 4.31 log10 CFU/mL, respectively), which was statistically different from all the other groups (P < 0.001). G4 showed the lowest mean contamination (0.24 log10 CFU/mL) with statistically significant value (P < 0.001). 2.5% NaOCl with ultrasonic activation can aid in significant fungal reduction. Ultrasonic activation of 2.5% NaOCl, 2.5% Ca(OCl)2, and MSS was also found to have improved antifungal activity against C. albicans.

Comparative Evaluation of Human Pulp Tissue Dissolution by 500-ppm and 200-ppm Hypochlorous Acid and 5.25% Sodium Hypochlorite: An In Vitro Study

AIM

The aim of this study was to assess, in vitro, the human pulp dissolution capacity of 500 ppm and 200 ppm of hypochlorous acid in comparison with 5.2% sodium hypochlorite (NaOCl).

MATERIALS AND METHODS

Forty pulp tissue samples were standardized to a weight of 9 mg and divided into four groups according to the irrigating solution used: 5.25% NaOCl, 500 ppm hypochlorous acid, 200 ppm hypochlorous acid, and distilled water. Eppendorf tubes carrying 2 mL of the irrigants were taken and the pulp tissue samples were placed in the tubes for the specified time interval: Subgroup A: 30 minutes and subgroup B: 60 minutes. After the designated time interval, the solution from each sample tube was filtered using Whatman filter paper and left for drying overnight. The residual weight was calculated by filtration method. The mean dissolution time for each experimental group at the different time intervals was statistically analyzed.

RESULTS

Mean tissue dissolution increases with an increase in the time period. Approximately 5.25% NaOCl was most effective at both time intervals followed by 500-ppm hypochlorous acid at 60 minutes. Least amount of tissue dissolution was shown by 200-ppm of hypochlorous acid at 30 minutes. Distilled water did not show the ability to dissolve human pulp tissue.

CONCLUSION

Within the limitations of the study, 5.25% NaOCl dissolved the pulp tissue most efficiently at both time intervals and both concentrations. Human pulp tissue dissolution by hypochlorous acid was found to gradually increase with time and with an increase in its concentration.

CLINICAL SIGNIFICANCE

With the basic information that hypochlorous acid does have the capacity to dissolve human pulp tissue, further research can be undertaken to assess methods to increase its efficiency. Sooner than later, hypochlorous acid may be able to completely replace the toxic NaOCl in clinical practice, as the irrigant of choice during root canal therapy.

Effect of herbal and chemical solution in tissue dissolution by using conventional irrigation and sonic irrigation system

Introduction:

An essential part of root canal cleaning is irrigating the system to remove any remaining debris and tissue remains. The purpose of root canal therapy is to shape and clean the endodontic space, reduce the bacterial burden, and remove the pulp tissue. In this research, several irrigation solutions with and without sonic irrigation were evaluated to see how quickly tissue dissolves.

Method:

A tissue sample was taken from a cow (68 ± 3 mg) with no statistically significant difference between groups. All five test tubes in each group were immersed in irrigant, and each group contained one subgroup with five test tubes. Separate weights were recorded for every irrigant that had been passed through the filter paper. Thus, the quantity of pulp dissolved by different irrigating solutions was quantified using a filtering technique.

Results:

It was revealed that there was a substantial difference between the groups. Sonic and non-sonic irrigation of sodium hypochlorite resulted in a substantial difference in tissue disintegration.

Conclusion:

This research found that sodium hypochlorite was more effective than EDTA and saline in dissolving pulp. Despite several studies claiming that neem has potent antibacterial activities, tissue dissolution has not been shown in experiments using this herb.

Comparative evaluation of pulp tissue dissolution ability of sodium hypochlorite by various activation techniques: An in vitro study

Background:

The success in endodontic therapy is dependent largely on the absolute elimination of pulp tissue remnants and the maximum reduction of pathologic microbial load present within the root canal system.

Aim:

The aim of this in vitro study was to compare and evaluate the ability of pulp tissue dissolution with and without activation of 5.25% sodium hypochlorite (NaOCl).

Materials and Methods:

Pulp tissue samples collected from intact, noncarious extracted third molars were standardized to 8 mg in each group. These samples were placed in conical Eppendorf tubes of 15 ml with 10 ml 5.25% NaOCl for 4 min and were activated suitably according to the group specifications. All the procedures in this study were carried out at room temperature. The preweighed pulp tissue samples were further weighed again after the dissolution phase, and residual weight loss in each group along with its percentage was obtained. The results were then statistically analyzed using one-way analysis of variance and Tukey post hoc test.

Results:

The maximum amount of pulp tissue dissolution was found in the laser-assisted irrigation group, i.e., NaOCl with Er, Cr: YSGG (P < 0.05) and showed a statistically significant result in comparison with other groups.

Conclusion:

Within the limitations of the study, laser-assisted irrigation with a radial firing tip (NaOCl activated by Er, Cr: YSGG) was the most effective in dissolving the pulp tissue in comparison with other groups. The ultrasonic activation also showed a considerable amount of pulp tissue dissolution comparable to laser-activated irrigation in this study.

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.

Calcium Hypochlorite Solutions - An In Vitro Evaluation of Antimicrobial Action and Pulp Dissolution

Objective:

To compare the antimicrobial activity and tissue dissolution capacity of calcium hypochlorite (Ca(OCl)₂) solution with sodium hypochlorite (NaOCl) solution at 0.5%, 1.0%, 2.5%, and 5.25% concentrations.

Methods:

To determine the inhibition halos produced by the tested substances against Enterococcus faecalis, the agar diffusion method was employed. Additionally, the broth contact method was used to determine the time required for the inhibition of E. faecalis. Bovine pulp fragments were used to test the dissolution. Half of the pulps were freely deposited samples in cell culture wells, and the remaining samples were fixed on bovine dentine bases.

Results:

For both Ca(OCl)₂ and NaOCl solutions, the greatest inhibition zones were observed at 5.25% con-centration. However, the most significant inhibition zone was measured with 5.25% Ca(OCl)₂ solution (17.38 mm). Hypochlorite solutions at 2.5% and 5.25% concentrations required less time to inhibit E. faecalis than those at 0.5% and 1.0% concentrations (P<0.05). There was no difference in inhibition times between 2.5% and 5.25% hypochlorite solutions (P>0.05). The most effective hypochlorite solution concentrations were 5.25% and 2.5% for dissolving pulp fragments (P<0.05). Additionally, suspended pulp fragments were more susceptible to dissolution than fragments attached to dentine blocks (P<0.05), except for 0.5% Ca(OCl)₂.

Conclusion:

Ca(OCl)₂ solutions showed antimicrobial activity against E. faecalis and can dissolve pulp tissues. Future studies are warranted to examine the suitability of Ca(OCl)₂ in the chemico–mechanical preparation of the root canal system.

Influence of surfactants addition on the properties of calcium hypochlorite solutions

Objectives

The aim of this study was to evaluate the influence of surfactants 0.2% or 0.1% cetrimide (Cet) or 0.008% benzalkonium chloride (BAK) on 2.5% calcium hypochlorite (Ca(OCl)₂), and compare to sodium hypochlorite (NaOCl), regarding the properties of pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity.

Material and Methods

The pH and free chlorine content were evaluated by digital pHmeter and by titration, respectively. Surface tension was measured by the platinum ring technique with a Du Noüy tensiometer. The solution's contact angle in human dentin surfaces was checked by Drop Shape Analyzer software. Bovine pulps were used for pulp dissolution analysis and the dissolving capacity was expressed by percent weight loss. Antimicrobial activity over Enterococcus faecalis was evaluated by the agar diffusion method.

Results

Surfactants addition to Ca(OCl)₂ and NaOCl did not alter the pH, free chlorine content and pulp dissolution properties. Ca(OCl)₂ had the highest surface tension among all tested solutions. When surfactants were added to Ca(OCl)₂ and NaOCl, there was a significant reduction of surface tension and contact angle values. The addition of 0.2% or 0.1% Cet enhanced antimicrobial activity of both Ca(OCl)² and NaOCl.

Conclusion

Surfactant addition to 2.5% Ca(OCl)² has shown acceptable outcomes for pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Furthermore, the addition of 0.2% Cet showed better results for all tested properties.

Activation of Alkaline Irrigation Fluids in Endodontics

In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

Sodium Hypochlorite Irrigation and Its Effect on Bond Strength to Dentin

Effective shaping and cleaning of root canals are essential for the success of endodontic treatment. Due to the complex anatomy of root canal spaces, the use of various instrumentation techniques alone is not effective in producing bacteria-free root canal spaces. Irrigation, disinfectants, rinses, and intervisit medications are used in conjunction with the mechanical instrumentation to ensure the success of endodontic treatment. Sodium hypochlorite (NaOCl), a halogenated compound, is routinely used to irrigate the root canal during endodontic treatments. NaOCl has been known for its antibacterial action, proteolytic and dissolution capacity, and debridement properties. NaOCl, however, can alter the composition of dentin and hence its interaction with the adhesive resins used to bond the restorative materials to treated dentin. This review therefore covers in depth the action of NaOCl on dentin-adhesive resin bond strength including both enhancement and reduction, then mechanisms proposed for such action, and finally how the adverse action of NaOCl on dentin can be reversed.