Intracanal Irrigants Research Articles

Effect on the mechanical properties of human and bovine dentine of intracanal medicaments and irrigants.

Evidence is lacking concerning the suitability of using bovine dentine in endodontic research. This study compared the mechanical properties of human and bovine root dentine using endodontic medicaments and irrigants. Standardized human and bovine dentine bars were allocated to six experimental groups (n = 15): calcium hydroxide paste (Calasept® Plus); Odontopaste® ; 0.5% and 1% NaOCl gels; 1% and 4% NaOCl solutions. The bars were exposed to the materials for 7 days and then immediately subjected to a three-point bend test and Vickers microhardness test. Data were analysed using analysis of variance with Fisher's pairwise comparisons, with P < 0.05. Human dentine displayed a significantly higher modulus of elasticity (P = 0.001), higher microhardness (P < 0.001), and lower flexural strength (P = 0.004) compared with bovine dentine. Calcium hydroxide and Odontopaste® did not result in a significant change to the mechanical properties of human dentine. In human dentine, 0.5% NaOCl gel caused a significant decrease in flexural strength (P < 0.001) and microhardness (P = 0.02). Bovine dentine was a suitable substrate relative to human dentine. The use of a 0.5% or 1% NaOCl gel as an intracanal medicament is not supported by this study.

The effect of human serum and dentin powder alone or in combination on the antibacterial activity of sodium hypochlorite against Enterococcus faecalis

ObjectiveDentin debris and organic components may affect the properties of intracanal irrigants. This study aimed to evaluate the effect of dentin powder (DP) and human serum (HS) on the antibacterial and antibiofilm activity of sodium hypochlorite (NaOCl) against Enterococcus faecalis. DesignDP from 100 to 6.25 mg/mL and HS from 10% to 0.3125% were interactively mixed and added into E. faecalis and 1% NaOCl solution. The live E. faecalis were counted after 1 min of contact. For biofilm testing, 7 days of E. faecalis biofilms were treated by 100 mg/mL DP and 10% HS alone or combination with 1% NaOCl solution for 1 min. Furthermore, after challenges, E. faecalis biofilms were stained with SYTO 9 and propidium iodide, and confocal laser scanning microscopy (CLSM) was used to determine the proportion of dead and live cells in the biofilm. ResultsOne hundred mg/mL DP or 10% HS alone showed the excellent inhibition of 1% NaOCl against planktonic E. faecalis, and the low concentration of DP and HS presented an additive inhibitory effect. The number of live bacteria in biofilms were significantly higher in the 1% NaOCl-treated group with DP or HS than without DP and HS (p < 0.05), and a higher percentage of dead bacteria was found in the challenge of NaOCl in the absence of DP and HS than in the presence of DP and HS. ConclusionDP and HS generated the inhibition of antibacterial and antibiofilm activities of NaOCl, whereas the effect of HS was greater than DP.

Comparison of Antibacterial Effect of Four Irrigation Solutions in Primary Root Canal Infections: A Clinical Study.

Reducing the bacterial count from the root canal system is one of the main stages in root canal treatment. The aim of the present clinical study was to compare the antibacterial effect of four intracanal irrigants in primary endodontic infections using both microbiological culture and quantitative Real-time Polymerase Chain Reaction (qRT-PCR) technique. Forty patients with primarily infected single rooted premolars were selected and then randomly divided into 4 groups according to the intra canal irrigant used: 5.25% Sodium hypochlorite (NaOCl), Hypoclean (Ogna Laboratori Farmaceutici, Muggiò, Italy), 2% chlorhexidine glouconate (CHX) and CHX-Plus (Vista Dental Products, Racine, WI, USA). Samples were collected before and after chemomechanical preparation and were evaluated by bacterial culture and RT-PCR technique for Enterococcus faecalis and Fusobacterium nucleatum. Data analyzed by repeated measured ANOVA. The significance level was set at 0.05. Four irrigation solutions significantly reduced the total numbers of cultivable bacteria (P<0.05). No statistically differences were found among the antibacterial effects of 5.25% NaOCl (99.93%), Hypoclean (99.94%), 2% CHX (99.77%) and CHX-Plus (99.83%) in reducing cultivable bacteria. Enterococcus faecalis and Fusobacterium nucleatum were no longer detected after preparation using four irrigants (100% reduction). All tested irrigants including 5.25% NaOCl, Hypoclean, 2% CHX and CHX-Plus significantly reduced the number of bacterial colonies in primary endodontic infections.

Antimicrobial assay of combination surfactant irrigant regimen on vancomycin-resistant Enterococcus faecalis. An in vitro direct contact test

Vancomycin-resistant enterococci (VRE) are on the rise globally in primary intraradicular infections and resistant to most intracanal irrigants and medicaments. The aim of this study was to evaluate the efficacy of irrigants and identify a cost-effective regimen to eradicate VRE. In this in vitro study irrigants were categorized as primary and surfactant groups with individual concentrations consisting of 10 samples each. Primary irrigants; sodium hypochlorite (NaOCl), chlorhexidine (CHX), and iodine potassium iodide (IKI) were prepared in concentrations of 5%, 2.5%, 2%, and 1%. Surfactants cetrimide (CTR) and sodium dodecyl sulfate (SDS) were prepared in concentrations of 0.25%, 0.5%, 1%, and 2%. Biopure MTAD was chosen as the control group. ATCC 51299 (VRE) was evaluated for antimicrobial susceptibility to the above irrigants by direct contact test for 5 min. The effect of each test irrigant was determined by calculating the percentage kill of viable bacteria by spectrophotometer. Statistical analysis was done by means of a one-way ANOVA and Mann-Whitney U-test (P < 0.05 consider significant). About 2.5% and 5% CHX were significant over mixture of tetracycline, acid and detergent (MTAD) (P < 0.05). 5% CHX could achieve 100% elimination while 2.5% CHX and 5% IKI had 99.90%. 2% CHX and 2.5% IKI had 99% effective kill percentage. All concentrations of NaOCl were ineffective (90%) as compared to MTAD (95%). CTR (0.5%, 1% and 2%) and SDS (2%) were significant (P < 0.05) over MTAD. Combination surfactant regimens of 2% CHX +0.5% CTR and 2% CHX +1% SDS achieved 99.90% eradication potential and were significant (P < 0.05) over MTAD. Surfactant regimens were highly effective and superior to MTAD. CTR and SDS by their organic solvent property enhanced the antibacterial action of CHX.

Relevance of the clustered regularly interspaced short palindromic repeats of Enterococcus faecalis strains isolated from retreatment root canals on periapical lesions, resistance to irrigants and biofilms.

A high prevalence of Enterococcus faecalis (E. faecalis) is observed in teeth with root canal treatment failures. Clustered regularly interspaced short palindromic repeats (CRISPR) are widely distributed in prokaryotes that have adaptive immune systems against mobile elements, including pathogenic genes. The present study investigated the relevance of the CRISPR in E. faecalis strains isolated from retreated root canals on biofilms, periapical lesions and drug resistance. A total of 20 E. faecalis strains were extracted from the root canals of teeth referred for root canal retreatment. CRISPR-Cas loci were identified by two pairs of relevant primers and polymerase chain reaction. The susceptibility of the 20 isolated strains to intracanal irrigants was evaluated by 1- and 5-minute challenges with a mixture of a tetracycline isomer, an acid and a detergent (MTAD), 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl). The microtiter plate assay and crystal violet staining were used to compare the biofilm formation of the E. faecalis isolate strains. Out of the 20 E. faecalis isolate strains, 5 strains that lacked CRISPR-cas determinants exhibited significant periapical lesions. Among the 15 strains containing CRISPR-cas determinants, 8 were isolated from root canals with inadequate fillings and 7 were isolated from root canals without any fillings. The five strains lacking CRISPR-cas loci were observed to be more resistant to MTAD and 2% CHX than the 15 strains that had CRISPR-cas loci. All of the strains exhibited the same susceptibility to 5.25% NaOCl. Furthermore, the 5 strains lacking CRISPR-cas determinants generated more biofilm than the other 15 strains. Thus, the results of the present study suggested that E. faecalis root canal isolates lacking CRISPR-cas exhibit higher resistance to intracanal irrigants, stronger biofilm formation and generate significant periapical lesions.

English

English

Influence of Intracanal Irrigants on Coronal Fracture Resistance of Endodontically Treated and Bleached Teeth: An In vitro Study.

Background:Irrigation has a key role in the success of endodontic treatment. Intracanal irrigant solutions have adverse effects on the physical properties of dentin.Aim:The present study aimed to evaluate the effect of different irrigation protocols on coronal fracture resistance of endodontically treated teeth undergoing bleaching treatment.Design and Materials and Methods:Access cavities were prepared in 120 maxillary premolars which were divided into two groups (n = 60) – Group A: nonbleached, Group B: bleached (B). Each group was subdivided into five subgroups based on irrigation protocol (n = 12); G1: normal saline (NS), G2: 2.5% sodium hypochlorite (NaOCl), G3: 10% citric acid (CA), G4: 17% ethylene diamine tetra acetic acid, and G5: NaOCl plus CA. In Group B, the teeth were bleached using 38% hydrogen peroxide and 20% carbamide peroxide gels as in-office and at-home bleaching techniques for 3 weeks. All the teeth were restored with composite resin, thermocycled, and incubated for 24 h. The specimens underwent fracture resistance tests. Data were analyzed with ANOVA, Tukey honestly significant difference test, t-test, and Chi-squared test (α =0.05).Results:T-test showed significant differences between each two corresponding subgroups (P < 0.0001). In Group A, NS demonstrated significantly higher fracture resistance compared to others; however, minimum fracture resistance recorded in G2. In Group B, the maximum fracture resistance was recorded in G1, with the minimum being recorded in G5. Samples irrigated with NaOCl and NaOCl plus CA exhibited significantly lower fracture resistance compared to NS subgroup (P < 0.05).Conclusions:Within the limitations of this study, it can be concluded that the irrigation protocol used during endodontic treatment with/without bleaching can affect the coronal fracture resistance.

Effects of inactivated Enterococcusfaecalis on the proliferation and osteogenic induction of osteoblasts.

The present study aimed to evaluate the effects of Enterococcus faecalis, inactivated by the common intracanal irrigants sodium hypochlorite (NaOCl) and chlorhexidine (CHX), on osteoblasts. E. faecalis was inactivated with 2% CHX or 5.25% NaOCl. Subsequently, the Cell Counting kit-8 assay was used to examine the effects of CHX- and NaOCl-inactivated E. faecalis on MC3T3-E1 osteoblast cell proliferation. Alizarin red staining was used to determine osteoblast mineralization, and osteogenic induction was quantified by determining the optical density of the dye solution. The relative expression levels of osteogenic genes were detected after 1, 4, 7 and 14 days of stimulation with CHX- and NaOCl-inactivated E. faecalis by reverse transcription-quantitative polymerase chain reaction. The results indicated that CHX-inactivated E. faecalis inhibited osteoblast proliferation, whereas NaOCl-inactivated E. faecalis did not suppress cell proliferation. Various concentrations of CHX- and NaOCl-inactivated E. faecalis induced different degrees of osteoblast mineralization. The expression levels of osteocalcin, alkaline phosphatase, runt-related transcription factor 2, osteopontin and osterix were upregulated in cells following stimulation with 107 and 105 colony-forming units/ml E. faecalis inactivated by CHX and NaOCl; the upregulation of these osteogenic genes occurred at various time points. In conclusion, the present study demonstrated that CHX-inactivated E. faecalis exerted more of an effect on osteoblast proliferation compared with NaOCl-inactivated E. faecalis. In addition, CHX- and NaOCl-inactivated E. faecalis was able to induce mineralization and relevant osteogenic gene expression in osteoblast cells.

Effect of Intracanal Irrigants on Bond Strength of Fiber Posts Cemented With a Self-adhesive Resin Cement

The aim of this study was to evaluate the effect of five intracanal irrigants on bond strength of fiber posts cemented with newer self-adhesive resin cement. A total of 60 extracted, single-rooted human premolars, sectioned at 14 mm, were prepared with the ProTaper Universal system with a size F3 instrument and filled with an F3 master cone and AH Plus. The root canal filling was partially removed, leaving 4 mm of apical gutta-percha. Specimens were randomly assigned to five groups (n=12), according to the solution used for dentin surface treatment before fiber post cementation, as follows: EDTA 17% (EDTA); QMix (QM); SmearClear (SC); 2.5% sodium hypochlorite (NaOCl), and 0.9% saline solution (SS). Ultrasonic activation was performed (three times, 20 seconds each), and root canals were dried with paper points. Fiber posts were cemented with RelyX U200. In one specimen per group, rhodamine B dye was mixed with RelyX U200 to provide adequate fluorescence for confocal laser scanning microscopy (CLSM) assessment. Specimens were transversally sectioned and three slices were obtained, one for each root third. Next, a push-out test was performed. A stereomicroscope and CLSM were used to analyze the failure modes and to illustrate the pattern of infiltration of RelyX U200 into dentinal tubules, respectively. Bond strength means were calculated, and analysis of variance and Bonferroni tests were used for statistical analysis. SS showed the highest mean bond strength values (11.5±5.3), superior to QM (5.1±3.1) and SC (5.1±3.3). NaOCl presented intermediary bond strength values (9.7±5.0), similar to EDTA (7.7±2.9) and SS. QM and SC showed the lowest mean bond strength (p<0.05). Adhesive failures between cement/dentin were predominant (53.9%). SS and NaOCl associated with ultrasonic activation seem to be adequate solutions for root canal cleaning before fiber post cementation with self-adhesive resin cement, whereas chelating solutions, such as EDTA, QM, and SC, cause a decrease in bond strength.

Intracanal irrigants for pulpectomy in primary teeth: a systematic review and meta-analysis.

To conduct a systematic review and meta-analysis to assess the findings on the clinical efficacy of intracanal irrigants employed during pulpectomy of primary teeth. A systematic search was performed in electronic databases and peer-reviewed paediatric dentistry journals to find relevant studies. Titles, abstracts, and full-text papers were located, screened, and assessed independently by two reviewers, and a meta-analysis was performed. The search identified a total of 775 records; 46 were selected and reviewed in full text. After screening, seven studies met the eligibility criteria for inclusion. Three studies compared the 2% chlorhexidine and saline solutions, but no analysis could be performed because of the heterogeneity between these; two of the studies reported non-comparative methodologies and results when compared, and were not analysed. Finally, two studies compared a mixture of tetracycline isomer, an acid, and a detergent (MTDA) or oxidative potential water (OPW) to sodium hypochlorite (NaOCl), without showing significant heterogeneity; therefore, their combined outcomes were included. Both fixed and random mixed models resulted in a non-significant weighted mean difference between treatments, according to a forest plot. More studies are required with adequate quality, as well as a full-result report, including summary measurements of both response variables and effect size, to determine the most effective irrigant agents for use in pulpectomies.

A Comparative Evaluation on Antimicrobial Effect of Honey, Neem Leaf Extract and Sodium Hypochlorite as Intracanal Irrigant: An Ex-Vivo Study.

The major determinant of the success of root canal treatment depends on meticulous disinfection of the root canal using intracanal irrigants. The most commonly used root canal irrigant is sodium hypochlorite which has disadvantages of cytotoxicity and unpleasant taste. So there is a need to identify a more biocompatible root canal irrigant. The aim of this ex-vivo study was to evaluate the efficacy of 40% honey, 100% neem leaf extract and 5.25% sodium hypochlorite as an intracanal irrigant against the isolated microorganisms from infected root canal. The samples were collected from infected root canals of 60 primary molar teeth indicated for pulpectomy. Alpha hemolytic Streptococci, gram negative bacilli, Candida, Staphylococci, Lactobacilli, Enterococci, Spore bearing gram positive bacilli and Micrococci were the microorganisms isolated from the samples. The zone of inhibition against the microbial growth was measured by agar well diffusion method. Statistical analysis was done by Repeated Analysis of Variance (ANOVA) and Bonferroni method. Statistical analysis showed that the means of the zones of inhibition measured in this study were 18.56mm, 2.09mm and 1.62mm for sodium hypochlorite, 100% neem leaf extract and 40% honey respectively. The significance was greater between sodium hypochlorite and the other two agents as p-value was <0.001. The results indicated that 5.25% sodium hypochlorite is more effective as root canal irrigant when compared with 100% neem leaf extract and 40% honey. It was also observed that 100% neem leaf extract has greater antimicrobial effect than 40% honey.

Evaluation of some intracanal irrigants on push-out bond strength and mode of failure of resin and non resin cements to root canal dentin (in vitro comparative study)

Objectives: The purpose of this study was to evaluate the effects of five intracanal irrigants [distilled water, NaOCl, NaOCl + EDTA, ozonated water and NaOCl + ozonated water] on push-out bond strength of (zinc phosphate cement and Calibra® esthetic resin cement) and to determine the mode of failure. Materials and Methods: Seventy extracted single straight rooted teeth were selected. The crowns were sectioned at cemento-enamel junction. The sectioned roots were embedded vertically in clear acrylic resin. The root canals were prepared with K-files and Gates Glidden drills using step-back technique then the specimens were randomly assigned to five main groups according to the types of irrigant used and each main group were divided in to two subgroups and filled with zinc phosphate cement and Calibra® esthetic resin cement. The samples were sectioned horizontally to provide 4 millimeter dentin disc from coronal third of the roots. Each sectioned specimen was tested by using computerized universal testing machine. Finally each de-bonded specimens was examined under stereomicroscope to determine the mode of failure. Results: Two-way ANOVA tests showed that there was statistical significance difference between the two type of cement used in this study, also there was statistical significance difference between the types of irrigant; while the interaction between types of cement with types of irrigant was not statistically significant. Considering the dentine surface treatment, Paired T-test showed that irrigation with 5.25% NaOCl produce statistically significant reduction in bond strength to root canal dentin in comparison to control group, while irrigation with distilled water, 5.25 NaOCl plus 17% EDTA, 5.25% NaOCl plus 5gm/L ozonated water, 5gm/L ozonated water alone had no statistical significant affect on bond strength to root canal dentin. Comparing the cements, zinc Phosphate cement showed higher bond strength in comparison to Calibra® esthetic resin cement. Conclusions: NaOCl have negative effect on bond strength to root canal dentin, while distilled water, NaOCl plus EDTA, ozonated water alone or after NaOCl had no effect. Zinc phosphate cement had higher bond strength than Calibra® esthetic resin cement. The adhesive and mixed failures were higher than the cohesive failure for all groups in general.

The effect of chlorine dioxide on Enterococcus faecalis in exponential, stationary and starvation phases in extracted human teeth - an invitro study

Background: Enterococcus Faecalis (E faecalis) is isolated usually from failed root canal treated teeth. It can bind to dentin and co-aggregate with other organisms. The organism is resistant to the intracanal medicaments and irrigants. It has the ability to produce biofilms and survive within the root canal. They may develop resistance at different phases of bacterial growth cycle. Objective: To study the effect of chlorine dioxide on different phases of E faecalis growth cycle for 1 and 3 min duration. Methodology: E faecalis ATCC strain (29212) was cultured in different growth phases on dentinal blocks of extracted human teeth. After treatment with chlorine dioxide, left out colonies were counted from dentinal shavings. Observation of the remaining biofilm of different phases was made using the scanning electron microscope and comparison between them was done. Results: In all 3 phases, at the end of 1 and 3 min, significantly (p&lt;0.01, p&lt;0.001 respectively) less E faecalis colonies were observed when compared to initial count. When effect of chlorine dioxide on E faecalis colonies was compared between the three phases, at the end of 1 min, significantly (p&lt;0.05) less E faecalis colonies were observed in exponential phase than in starvation phase. However, the E faecalis colony count during stationary phase was significantly (p&lt;0.05) less than the colony counts in both exponential and starvation phases. At the end of 3 min, there was no significant difference in E faecalis colony count between exponential and starvation phases. However, the E faecalis colony count during stationary phase was significantly (p&lt;0.05) less when compared to the colony counts in both exponential and starvation phases. Conclusion: Our study showed that starved cells of E faecalis were more resistant to 13.8% chlorine dioxide irrigant when treated for 1 and 3min. Keywords: E faecalis, Chlorine dioxide, Dentinal blocks, Biofilms.

Primjena lasera u dezinfekciji i čišćenju korijenskih kanala zuba: pregledni rad

The outcome of root canal treatment is based on efficient disinfection of the root canal system and prevention of reinfection. Current chemomechanical cleaning methods do not always achieve these goals, and insufficient root canal disinfection is the main reason for endodontic failure. Due to high energy content and specific characteristics of laser light, laser treatment has been proposed for cleaning and disinfecting the root canal system. This paper reviews the literature covering the effect of Er:YAG, Er,Cr:YSGG, Nd:YAG and diode laser on the root canal wall in the removal of smear layer and against intracanal bacteria. Recently, the use of laser energy to induce cavitation and acoustic streaming of intracanal irrigants has been investigated. Based on recent literature, it can be concluded that lasers have bactericidal effects. However, they still cannot replace sodium hypochlorite and should be considered as an adjunct to the current chemical root canal disinfection protocols. Certain lasers can help in removing the smear layer and debris and can modify the morphology of the root canal wall. Unfortunately, there have not been enough randomized clinical studies evaluating endodontic treatment outcome following the use of laser.

Propolis and Commonly Used Intracanal Irrigants. Comparative Evaluation of Inflammatory Potential

The present study evaluated the inflammatory/irritant potential of propolis in comparison with commonly used intracanal irrigants such as chlorhexidine and calcium hydroxide, with normal saline solution as control using an animal (Wistar rats) model. 2% Evans blue was intravenously injected into the lateral caudal vein. 0.1 ml each of the test solutions was intradermally injected into the experimental sites designed on their shaved backs. The animals were then sacrificed after 1 1/2 and 3 hours respectively. Each piece of skin containing the injected solution was excised, immersed in 4 ml formamide and incubated at 45 degrees C for 72 hours. After filtration with glass wool, optical density(OD) was measured using a spectro-photometer and analyzed statistically. At 620 nm irrespective of time, the mean optical density with Calcium Hydroxide was found to be maximum (0.197 +/- 0.095) while that with DMSO Propolis was found to be minimum (0.070 +/- 0.016). Both at 90 min and 180 min, the mean optical density with Calcium Hydroxide was found to be maximum. On short-term evaluation, maximum inflammation was seen with calcium hydroxide followed by chlorhexidine and DMSO extract of propolis. Minimum inflammation was seen with sterile physiologic saline. With progress of time, maximum inflammation was seen with calcium hydroxide followed by chlorhexidine and DMSO extract of propolis which was non-significant.

Comparative evaluation of biofilm formation ability of E.faecalis in alkaline conditions and its susceptibility to endodontic irrigant regimens – An In vitro microbiological study.

The present study aimed to evaluate the alkaline tolerance ability of Enterococcus faecalis; one of the most commonly isolated bacterium from failed root canal treatments. E. faecalis was grown in Brain heart Infusion (BHI) broth and maintained at different alkaline conditions (pH); its ability to form biofilm in polystyrene plates was assayed by O’Toole method. Intracanal irrigants sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX) and MTAD were used to evaluate the suppression of E. faecalis biofilm. The data obtained was statistically analysed by Anova and Kolmogorov-Smirnov test. E. faecalis was able to survive and form biofilm at all tested pH range (7.3-12.3). 2% NaOCl and 1% CHX were highly effective in suppressing E. faecalis biofilm whereas MTAD had limited activity.

In vitro comparison of antimicrobial effect of three intracanal irrigants and diode laser on canals infected with Enterococcus faecalis

In vitro comparison of antimicrobial effect of three intracanal irrigants and diode laser on canals infected with Enterococcus faecalis

Non-surgical endodontics in retreatment of periapical lesions - two representative case reports

This article reports non-surgical endodontic retreatment of two patients with persistent or recurrent periapical lesions, who had previously undergone surgical and non-surgical endodontic therapy respectively. It further discusses and reviews the relevance of classification of periapical lesions, the explanation behind healing of periapical lesions by endodontic therapy alone, causes of persistence of periapical lesions, choice of treatment modalities (whether surgical or non – surgical) and materials such as intracanal medicaments and irrigants for optimal healing. Key words:Non-surgical, retreatment, periapical, calcium hydroxide, chlorhexidine irrigation.

Effect of intracanal irrigants on the bond strength of epoxy resin‐based and methacrylate resin‐based sealers to root canal walls

To assess the bond strength of Epiphany and AH Plus sealers to root canal walls using a push-out test after use of several endodontic irrigants. Roots of 100 maxillary canines were sectioned horizontally 5 mm below the cemento-enamel junction to provide 4-mm-thick dentine disks that were embedded in acrylic resin and had their root canals prepared with a tapered bur (larger diameter=2.70 mm; smaller diameter=2.30 mm; length = 4 mm). The specimens were randomly assigned to five groups (n=20) according to the dentine surface treatment: I - 1% NaOCl (30 min); II - 1% NaOCl (30 min) + 17% EDTA (5 min); III - 17% EDTA (30 min); IV - 24% EDTA gel (30 min); V - 2% chlorhexidine gluconate (CHX) gel (30 min). In each group, two specimens were prepared for scanning electron microscopy to examine the surface of root canal dentine after use of each irrigant. The other 18 specimens were filled with AH plus (n = 9) or Epiphany (n=9) and subjected to a push-out test in an Instron machine. Data (in MPa) were subjected to statistical analysis by two-way anova and post-hoc Tukey-Kramer test (P < 0.05). AH Plus had a significantly higher bond strength (8.74 ± 2.75) than Epiphany (6.74 ± 3.97) (P < 0.05). One per cent NaOCl/17% EDTA was associated with significantly higher bond strength values (10.88 ± 3.05) than the other irrigants (P < 0.05). Seventeen per cent EDTA (8.75 ± 1.75), 24% EDTA gel (7.48 ± 3.48) and 2% CHX gel (7.89 ± 3.41) had intermediate values that were not significantly different from each other (P > 0.05). One per cent NaOCl was associated with the lowest mean values (3.70 ± 0.86) (P < 0.05). The interaction between surface treatment and sealer revealed significantly higher bond strength for 24% EDTA gel with AH Plus, 2% CHX gel with AH Plus and 1%NaOCl/17%EDTA with Epiphany (P < 0.05). Except for 1% NaOCl, the removal of smear layer with the other irrigants increased the bond strength of AH Plus to intracanal dentine. The use of 1% NaOCl for 30 min with 17% EDTA as final irrigant for 5 min increased the bond strength of Epiphany.

Ozone therapy in dentistry: A literature review

This review of literature is an attempt to summarize different modalities of ozone application in dentistry. Ozone gas has a high oxidation potential and is effective against bacteria, viruses, fungi, and protozoa. It also has the capacity to stimulate blood circulation, platelets, and immune response. Ozone is used in dentistry in gaseous, ozonated water and as ozonated oils. Ozone was shown to be biocompatible and is used in all aspects of dentistry. It has been shown to stimulate remineralization of recent caries-affected teeth and is used as a preventive therapy in caries, root caries, and intracanal irrigants in endodontic treatment. It has been used in treatment of alveolitis, avascular osteonecrosis of the jaw, and herpes virus infection. It also inhibits plaque formation and can be used as an adjuvant in periodontal surgical and maintenance phase. Ozone has also been used in dental unit water line to disinfect water. Advantage of ozone therapy is it is an atraumatic, biologically based treatment. While laboratory studies suggest a promising potential of ozone in dentistry, less number of clinical studies were documented. More number of randomized, controlled trials need to be conducted to determine the precise indications and guidelines to treat various dental pathologies with this promising medical agent.