Comparative effects of two endodontic irrigants, chlorhexidine digluconate and sodium hypochlorite, on macrophage adhesion to plastic surfaces

Cytotoxic effects of a chlorhexidine mouthwash and of an enzymatic mouthwash on human gingival fibroblasts

The aim of this study was to evaluate the cytotoxic effects of an enzymatic mouthwash and of a chlorhexidine mouthwash on human gingival fibroblasts. The metabolic activity of the fibroblasts exposed to each mouthwash was assessed by the MTT assay and the protein content was assessed by the SRB assay. The flow cytometry was used to evaluate the cell cycle and the types of cell death. The oxidative status was evaluated through the DCF and the DHE probes and the intracellular GSH concentration and the mitochondrial membrane potential through JC-1. The cytotoxicity of both mouthwashes was found to be dependent on the exposure time and on the concentration. However, the cytotoxicity of the enzymatic mouthwash was found to be lower than that of the chlorhexidine mouthwash. A trend towards increased oxidative stress was observed for both mouthwashes. After exposing the fibroblasts to the mouthwashes, a G2/M phase block was observed and cell death occurred predominantly by necrosis. The effects of chlorhexidine on fibroblasts were identified at lower concentrations than those used in clinical practice. Therefore, the use of chlorhexidine as an antiseptic in surgical and postoperative situations should be limited. In order to clarify the clinical significance of the enzymatic mouthwash cytotoxicity new clinical studies will be necessary.

Antimicrobial Efficacy of Different Natural Extracts Against Persistent Root Canal Pathogens: An In vitro Study

Introduction:

The spread of drug-resistant pathogens is one of the most serious threats to successful treatment of microbial diseases. Extracts of plants such as flowers, buds, seeds, leaves, twigs, bark, herbs, wood, fruits, and roots have evoked interest as sources of natural products. Irrigation with a broad-spectrum antiseptic substance and inter-appointment intracanal medication has become a standard regimen in root canal therapy.

Aim:

The aim of this study is to compare the antimicrobial efficacy of different natural extracts such as guava leaf extract, Aloe vera extract, papaya leaf extract, and cashew apple extract against Enterococcus faecalis and Candida albicans.

Materials and Methods:

The antimicrobial activity was determined using agar diffusion test. The solutions were divided into four groups: Group I – guava leaf extract, Group II – A. vera extract, and Group III – papaya leaf extract, and Group IV – cashew apple extract. The zones of inhibition of growth were recorded. The strains used for this study were E. faecalis ATCC 29212 and C. albicans ATCC 90028.

Results and Conclusion:

Sodium hypochlorite had demonstrated the best results among the tested solutions. Among the herbal extracts, cashew apple extract and guava leaf extract had shown statistically significant activity against E. faecalis and C. albicans.

Comparison of the Antibacterial Efficacy of Tea Tree Oil with 3% Sodium Hypochlorite and 2% Chlorhexidine against E. faecalis: An in vitro Study

Background and objectives

Among the bacterial species which most often cause endodontic failure, Enterococcus faecalis is the most important. This study compared the antibacterial efficacy of tea tree oil with 3% sodium hypochlorite and 2% chlorhexidine as a root canal irrigant, against E. faecalis

Materials and Methods

Normal saline, tea tree oil, 3% sodium hypochlorite, 2% chlorhexidine and fresh stains of E. faecalis were used. Four round wells, 4 mm deep and 8 mm diameter, were punched using sterile cork borer in blood agar plates and divided into four groups: group A: normal saline (control), group B: 3% sodium hypochlorite, group C: 2% chlorhexidine and group D: tea tree oil. Agar well diffusion method was performed to compare the antibacterial efficacy of tea tree oil, 3% sodium hypochlorite and 2% chlorhexidine.

Results

The results were tabulated and statistically analyzed using analysis of variance (ANOVA). Tea tree oil showed comparable inhibition of bacterial growth with sodium hypochlorite and chlorhexidine. No zone of inhibition was shown by normal saline (control).

Interpretation and conclusion

Tea tree oil showed statistically significant antimicrobial activity against Enterococcus faecalis, which is very much similar to sodium hypochlorite and chlorhexidine.

Abbreviations

CHX: Chlorhexidine; E. faecalis: Enterococcus faecalis; NaOCl: Sodium hypochlorite.

How to cite this article

Kamath U, Sheth H, Ramesh S, Singla K. Comparison of the Antibacterial Efficacy of Tea Tree Oil with 3% Sodium Hypochlorite and 2% Chlorhexidine against E. faecalis: An in vitro Study. J Contemp Dent 2013; 3(3):117-120.

Effect of Aquatine Endodontic Cleanser on smear layer removal in the root canals of ex vivo human teeth

Objectives

The purpose of this study was to measure and compare the root canal cleanliness and smear layer removal effectiveness of Aquatine Endodontic Cleanser (Aquatine EC) when used as an endodontic irrigating solution in comparison with 6% sodium hypochlorite (NaOCl).

Material and Methods

Forty-five human teeth were randomly allocated to five treatment groups; the pulp chamber was accessed, cleaned, and shaped by using ProTaper and ProFile rotary instrumentation to an ISO size #40. The teeth were then processed for scanning electron microscopy, and the root canal cleanliness and removal of smear layer were examined.

Results

The most effective removal of smear layer occurred with Aquatine EC and NaOCl, both with a rinse of EDTA.

Conclusions

Aquatine EC appears to be the first hypochlorous acid approved by the FDA to be a possible alternative to the use of NaOCl as an intracanal irrigant. Further research is needed to identify safer and more effective alternatives to the use of NaOCl irrigation in endodontics.

In vitro comparison of chlorhexidine and povidone-iodine on the long-term proliferation and functional activity of human alveolar bone cells

This work reports the behaviour of osteoblastic human alveolar bone cells (first subculture) in the presence of chlorhexidine (CHX) and povidone-iodine (PI). Short contact (2 min) of 24-h cultures with CHX, at 0.12 and 0.2%, and PI, at 5 and 10%, caused cell death within minutes; contact with 1% PI resulted in loss of the elongated characteristic cell shape. Cell adhesion was adversely affected at concentrations higher than 5 x 10(-5)% CHX or 0.05% PI. Long-term exposure to CHX at 10(-5) and 10(-4)% or PI at 10(-4)% had little effect on cell growth and caused an induction in the synthesis of alkaline phosphatase (ALP). Concentrations of CHX and PI similar and higher than, respectively, 5 x 10(-4)% or 0.05% caused dose-dependent deleterious effects. CHX affected mainly the cell growth, whereas the effects of PI were observed mostly in ALP production and matrix mineralization. Considering the levels of CHX and PI used routinely in the oral cavity, results suggest that CHX has a higher cytotoxicity profile than PI. This observation might have some clinical relevance regarding the potential utility of PI in the prevention of alveolar osteitis.

Effect of aqueous extract from Neem (Azadirachta indica A. Juss) on hydrophobicity, biofilm formation and adhesion in composite resin by Candida albicans

OBJECTIVE

Azadirachta indica, a Meliaceae family tree, has been used in India for many years in the treatment of several diseases in medicine and dentistry. Current research analyses the effects of the leaf aqueous extract from Azadirachta indica (Neem) on the adhesion, cell surface hydrophobicity and biofilm formation, which may affect the colonisation by Candida albicans.

METHODS

Azadirachta indica extract was tested in vitro on strains of Candida albicans 12A and 156B. Changes in hydrophobicity were reported in assays of yeast adhesion to hydrocarbons, in biofilm formation with glucose and in the adhesion of the microorganisms on light cured composite resin. Assays involved enumeration of candidal colony-forming units together with scintillation counting of radiolabelled Candida and compared to a solution of chlorhexidine digluconate 0.125% widely used in dentistry.

RESULTS

Yeast growth in Neem extract was not inhibited in concentrations ranging from 0.1mg/ml. A statistically significant increase (p<0.05) in cell surface hydrophobicity was evident for the two strain tested and there was also an associated increase in biofilm formation after contact with Neem extract in concentration 0.01 g/ml. Decrease in adhesion capacity of cells to composite resin was also recorded.

CONCLUSION

An anti-adhesive mechanism of action by Azadirachta indica is proposed based on the results observed.

The effect of German chamomile (Marticaria recutita L.) extract and tea tree (Melaleuca alternifolia L.) oil used as irrigants on removal of smear layer: a scanning electron microscopy study

AIM

To compare the cleaning effectiveness of chamomile hydroalcoholic extract and tea tree oil to 2.5% sodium hypochlorite (NaOCl) solution as an intracanal irrigant for the removal of the smear layer.

METHODOLOGY

Forty extracted, single-rooted, mature, permanent, human teeth were allocated at random into one of three experimental groups of ten teeth and two control groups of five teeth. For each tooth, the pulp chamber was accessed and the canal prepared using K-type files and Gates-Glidden burs, using a step-back technique; the apical stop was prepared to a size 30. Each canal was subsequently irrigated with one of the following solutions: distilled water (as a negative control), 2.5% NaOCl + 17% ethylenediamine tetraacetic acid (EDTA) (as a positive control), chamomile or tea tree oil or 2.5% NaOCl. Each tooth was split longitudinally and prepared for examination by scanning electron microscopy (SEM). The quantity of smear layer remaining on the three levels of each canal (coronal, middle and apical) was examined using magnifications of 2000 and 5000x. The data were analysed using nonparametric Kruskal-Wallis and Mann-Whitney U-tests.

RESULTS

The most effective removal of smear layer occurred with the use of NaOCl with a final rinse of 17% EDTA (negative control) followed by the use of a chamomile extract. Chamomile extract was found to be significantly more effective than distilled water and tea tree oil (P < 0.008). The use of a 2.5% NaOCl solution alone, without EDTA and that of tea tree oil, was found to have only minor effects. There was no statistical difference between distilled water, 2.5% NaOCl and tea tree oil.

CONCLUSIONS

The efficacy of chamomile to remove smear layer was superior to NaOCl alone but less than NaOCl combined with EDTA.

Evaluation of biocompatibility of sodium perborate and 30% hydrogen peroxide using the analysis of the adherence capacity and morphology of macrophages

OBJECTIVE

The purpose of this study was to evaluate the biocompatibility of the most used bleaching materials for pulpless teeth, sodium perborate and 30% hydrogen peroxide, in an experimental model of macrophages, through analysis of the adherence index and the cellular morphology.

METHODS

Inflammatory macrophages were obtained from peritoneal washed of Wistar rats. The evaluation of the adherence capacity of these cells to the plastic surface was conducted in Eppendorf tubes containing RPMI, after treatment with the bleaching agents diluted in 1:10, 1:100 and 1:1000 for 15 and 30 min, and incubation at 37 degrees C and humidified atmosphere of 5% CO(2) in air. The cellular morphology was verified after incubation of the cells treated with the bleaching agents in culture plaques and compared with normal cells in culture medium.

RESULTS

Results showed that sodium perborate neither increased the adherence index, nor altered the cellular morphology when compared to the control group. The distribution, cellular morphology, cytoplasmatic and nuclear characteristics, reproduced the aspects observed in normal macrophages. However, the treatment with 30% hydrogen peroxide presented an increase in adherence index when compared to the control group (RPMI), in all dilutions, according to Mann-Whitney test (n=08 and p=0.001 for dilutions 1:10 and 1:100, and n=08 and p=0.004 for dilution 1:1000). The morphology of the cells treated with this product presented structural alterations proportionally greater, depending on the dilution of this bleaching agent, and even in the highest dilution (1:1000) the cells presented very evident alterations.

CONCLUSIONS

This irreversible cellular damage as well as the elevation of the adherence index, characterizes the aggressive potential of 30% hydrogen peroxide, regardless of its dilution. Sodium perborate, on the other hand, showed biocompatibitity, since, no morphological nor functional alteration was observed in macrophages.

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant

AIM

To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants.

METHODOLOGY

A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system.

RESULTS

The best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third.

CONCLUSIONS

The apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.

Inflammatory response to different endodontic irrigating solutions

AIM

The aim of this study was to evaluate the inflammatory response to irrigating solutions injected into the peritoneal cavity of mice.

METHODOLOGY

Sixty mice received intra-peritoneal injections of 0.3 mL of 0.5% sodium hypochlorite, 2.0% chlorhexidine digluconate or phosphate buffered saline (PBS, control). Five animals of each group were sacrificed at 4, 24, 48 h and 7 days after the injection. Liquid from the peritoneal cavity of each animal was collected for the total and differential counting of inflammatory cells and protein leakage.

RESULTS

The 0.5% sodium hypochlorite solution group had greater migration of neutrophils and mononuclear cells to the peritoneal cavity from 48 to 168 h (P < 0.05). There was a significant increase in protein leakage to the peritoneal cavity after 4 up to 48 h in the 0.5% sodium hypochlorite group compared to the control group. Protein leakage was similar in all groups at 168 h. The 2.0% chlorhexidine group had similar results to the control group at all time periods.

CONCLUSIONS

The 0.5% sodium hypochlorite solution induced an inflammatory response, however, the 2.0% chlorhexidine digluconate solution did not induce a significant inflammatory response.

Accuracy of a new apex locator: an in vitro study

AIM

The purpose of this study was to test in an in vitro model the accuracy of a Bingo 1020 electronic apex locator, to compare the results to those of a well known apex locator, Root ZX, as well as to those of the radiographic method of tooth length determination.

METHODOLOGY

A total of 120 extracted teeth, preserved in Thymol solution and kept refrigerated, was used for the study. The experiment was performed on single-rooted teeth and on one-root canal, chosen randomly, in multirooted teeth. The teeth were randomly divided into 12 groups of 10 teeth each. After access preparation, the actual length (AL) was measured. The teeth were embedded in an alginate model specially developed for testing apex locators. Electronic tooth length measurements (EL) were carried out prior to root canal preparation using the two electronic apex locators (EAL) - Root ZX and Bingo 1020; three measurements were taken and an average computed. After the third measurement, the file was left in the root canal and a periapical radiograph was taken. The radiographic length (RL) was recorded by measuring the file length from the coronal reference point to the tip of the file. Each root canal was then prepared to a no. 40 K-file diameter using a standardized technique; saline was used for irrigation. Upon completion of the root canal preparation, EL measurements were taken by each EAL in dry conditions and with different irrigation solutions. Each measurement was repeated three times. The RL was recorded according to the last EL measurement. Results were subjected to statistical analysis.

RESULTS

In all parameters tested, a significant statistical difference was found between Bingo 1020 and the Root ZX. Measurements obtained using the Bingo 1020 were consistently closer to the AL (0.08 mm) than those obtained using the Root ZX. Both EALs measured the tooth length with great accuracy and a positive correlation of 0.76 (P = 0.00) existed between the two devices. No significant difference was found between the two apex locators when measurements were taken with the different irrigants (P = 0.34) and the content of the root canal did not affect the accuracy of the measurements. Lengths obtained by calculations from the radiographs were longer than the AL as well as the length obtained by both EALs (P = 0.00).

CONCLUSIONS

The Bingo 1020 proved to be as reliable as Root ZX and was user friendly. Under the experimental conditions, electronic measurements were more reliable than radiographs in the process of root length determination.

In vitro studies of the efficacy of antimicrobials against fungi

OBJECTIVE

The purpose of this study was to compare the efficacy of Listerine Antiseptic, Tartar Control Listerine Antiseptic, and Peridex mouthrinses and a 0.2% chlorhexidine digluconate solution against known pathogenic fungi.

STUDY DESIGN

Standardized methods were used to compare the antimicrobial efficacy of the above agents versus representative fungal species. Minimum inhibitory concentration-minimum fungicidal concentrations in macrobroth dilutions, suspension kill-time, and effectiveness against an artificial biofilm-attached population were studied.

RESULTS

All antimicrobials tested were effective against the fungal species under investigation at the concentration available commercially. Listerine Antiseptic showed a greater efficacy against attached artificial biofilm populations than the other antimicrobials tested.

CONCLUSIONS

Listerine Antiseptic, Tartar Control Listerine Antiseptic, and Peridex mouthrinses show promise as a means to control the pathogenic fungal species under investigation and may have applications to reduce oral colonization.