Effect of radiotherapy, immediate dentin sealing and irrigation simulating single- or two-visits endodontic treatment on the bond strength to pulp chamber dentin: an in vitro study.

This study aimed to evaluate the influence of radiotherapy and different endodontic treatment protocols on the bond strength to pulp chamber dentin. Eighty mandibular molars were randomly divided into two groups (n = 40): non-irradiated and irradiated (60 Gy). The pulp chambers were sectioned, and each group was subdivided (n = 8), according to the endodontic treatment protocol: no treatment (Control); Single-visit; Two-visits; Immediate dentin sealing (IDS) + single-visit; and IDS + two-visits. Each endodontic treatment visit was simulated through irrigation with 2.5% NaOCl, 17% EDTA and distilled water. IDS was performed by actively applying two coats of a universal adhesive to the lateral walls of the pulp chamber. After, the pulp chambers were restored with resin composite and four sticks were obtained for microtensile test. In addition, the dentin of the pulp chamber roof was assessed for surface roughness, chemical composition, and topography after each treatment protocol. Two-way ANOVA, Tukey's post hoc, Mann-Whitney, Kruskal-Wallis and Dunn's post hoc were performed (α = 5%). The treatment protocol affected bond strength (p < 0.05), while the irradiation did not (p > 0.05). The control group presented the highest values (p < 0.05). The single-visit group demonstrated better performance compared to the other groups (p < 0.05), which did not differ from each other (p > 0.05) The use of IDS changed the surface roughness (p < 0.05), chemical composition (p < 0.05) and topography of the dentin. In conclusion, the treatment protocol influenced dentin adhesion, while irradiation did not.

Endodontic irrigants from a comprehensive perspective.

This review article explores the fundamental principles of modern endodontics with a focus on root canal cleaning and shaping. It reviews commonly used endodontic irrigant, namely sodium hypochlorite (NaOCl), herbal extracts, chlorhexidine (CHX), and chelating agents, highlighting their properties, applications, and potential drawbacks. NaOCl, a key antimicrobial agent, demonstrates effectiveness against various microorganisms but poses challenges such as high cytotoxicity. Herbal extracts, gaining recognition in endodontics, present an alternative with potential advantages in preserving dentin integrity. CHX, known for its broad-spectrum antimicrobial activity, is discussed in both liquid and gel formulations, emphasizing its role in reducing smear layer formation and preserving hybrid layer durability. Chelating agents, specifically ethylenediaminetetraacetic acid and citric acid, play a vital role in removing the smear layer, enhancing dentin permeability, and facilitating the penetration of antimicrobial agents. The review article underscores the importance of careful application and consideration of each irrigant's properties to ensure safe and effective endodontic procedures. It serves as a valuable guide for clinicians in selecting appropriate irrigants based on specific treatment requirements.

Adhesive Performance of Pit and Fissure Sealants on Deproteinized Enamel with Different Proteolytic Agents: In Vitro Study.

The objective of this work was to assess the efficacy of different proteolytic agents on the bond strength of pit and fissure sealants to bovine enamel. Eighty-four bovine enamel specimens were randomly assigned in groups according to the pit and fissure sealant applied (HelioSeal F or Dyad Flow). Then, the specimens were subdivided according to the proteolytic agent used (n = 7): Group 1, distilled water (control); Group 2, 10 wt.% Tergazyme®; Group 3, 10 wt.% ZYME®; Group 4, 10% papain gel; Group 5, 10% bromelain gel; and Group 6, 5.25 wt.% sodium hypochlorite. The cell viability of the proteolytic solutions was assessed through the MTT assay. The proteolytic agents were applied on the enamel surface prior to the acid-etching procedure; then, the pit and fissure sealants were placed. The micro-shear bond strength was evaluated after 24 h or 6 months of water storing at 37 °C. Representative SEM images were taken for each experimental group. The bond strength data were statistically analyzed by a three-way ANOVA test using a significance level of α = 0.05. Bromelain and papain proteolytic solutions did not exert any cytotoxic effect on the human dental pulp cells. After 24 h and 6 months of aging, for both pit and fissure sealants, sodium hypochlorite, papain, bromelain, and Tergazyme® achieved statistically significant higher bond strength values (p < 0.05). Irrespective of the deproteinizing agent used, Dyad Flow resulted in a better bond strength after 6 months of aging. The type 1 etching pattern was identified for sodium hypochlorite, papain, and bromelain. Tergazyme®, papain, and bromelain demonstrated efficacy in deproteinizing enamel surfaces prior to acid etching, leading to the improved bond strength of pit and fissure sealants. Clinically, this suggests that these proteolytic agents can be considered viable alternatives to traditional methods for enhancing sealant retention and longevity. Utilizing these agents in dental practice could potentially reduce sealant failures.

Evaluation of pulp tissue dissolution capacity through different sodium hypochlorite agitation protocols.

Aims: This ex vivo study aimed to assess the dissolving capacity of 2.5% sodium hypochlorite using eight agitation protocols within swine pulp tissue. Subjects and Methods: Twelve lower first premolars were prepared and split into the fragments with a groove housing porcine dental pulp. Groups were assigned based on agitation systems: manual, passive ultrasonic, Easy Clean and XP-Endo Finisher. Two agitation time protocols were applied: One min (3 s × 20 s cycles) and 2 min (6 s × 20 s cycles). Wilcoxon Mann-Whitney U test was used to compare the groups. Results: Both time frames demonstrated superior results compared to manual group (P > 0.5). However, in the two min groups, no significant differences were observed among the other protocols (P < 0.5). Intriguingly, increasing cycle numbers significantly improved results within each group (P > 0.5). Conclusion: Extending the chemical agitation time during final irrigation enhances tissue removal, regardless of the irrigation protocol employed.

Exploring the Antimicrobial Efficacy of Low-Cost Commercial Disinfectants Utilized in the Agro-Food Industry Wash Tanks: Towards Enhanced Hygiene Practices.

The increase in vegetable consumption has underlined the importance of minimizing the risks associated with microbiological contamination of fresh produce. The critical stage of the vegetable washing process has proven to be a key point for cross-contamination and the persistence of pathogens. In this context, the agri-food industry has widely adopted the use of disinfectants to reduce the bacterial load in the wash water. Therefore, we conducted laboratory-scale experiments in order to demonstrate the antimicrobial activity of disinfectants used in the wash tank of agro-food industries. Different wash water matrices of shredded lettuce, shredded cabbage, diced onion, and baby spinach were treated with sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and per-oxyacetic acid (PAA) at recommended concentrations. To simulate the presence of pathogenic bacteria, a cocktail of E. coli O157:H7 was inoculated into the process water samples (PWW) to determine whether concentrations of disinfectants inhibit the pathogen or bring it to a viable non-culturable state (VBNC). Hereby, we used quantitative qPCR combined with different photo-reactive dyes such as ethidium monoazide (EMA) and propidium monoazide (PMA). The results indicated that concentrations superior to 20 ppm NaClO inhibit the pathogen E. coli O157:H7 artificially inoculated in the process water. Concentrations between 10-20 ppm ClO2 fail to induce the pathogen to the VBNC state. At concentrations of 80 ppm PAA, levels of culturable bacteria and VBNC of E. coli O157:H7 were detected in all PWWs regardless of the matrix. Subsequently, this indicates that the recommended concentrations of ClO2 and PAA for use in the fresh produce industry wash tank do not inhibit the levels of E. coli O157:H7 present in the wash water.

Sealing of pulp chamber dentin in endodontics: Influence of bond strategy and time-point application.

Context: Seal the dentin of the pulp chamber during endodontic treatment to avoid interfering with the restorative treatment performed afterward. Aims: The aim was to evaluate the effect of three adhesive systems applied in different bonding strategies (etch-and-rinse, self-etch, and universal adhesive) and time-point application (immediately after the cavity access preparation or after endodontic obturation) on the hybrid layer formation and dentinal penetrability. Materials and Methods: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used and the time-point application: Adper Scotchbond Multi-purpose (AS), Clearfil SE (CF) and Scotchbond Universal (SU) in strategy of immediate endodontic sealing (IES) or delayed endodontic sealing (DES). In IES-AS, IES-CF, and IES-SU groups, dentin sealing was performed immediately after the cavity access, while in DES-AS, DES-CF, and DES-SU, after root canal obturation. The specimens were sectioned in the long axis, in a buccal-lingual direction, and the dentinal penetrability of the adhesive systems was evaluated using confocal microscopy images. Hybrid layer formation was analyzed by scanning electron microscopy images. Statistical Analysis Used: Dentinal penetrability data were analyzed with the ANOVA test and the Kruskal-Wallis test was performed for hybrid layer data (α = 0.05). Results: IES-CF showed the lowest dentinal penetrability (P < 0.05), while the other protocols were similar to each other (P > 0.05). No significant differences were found between groups regarding the hybrid layer formation (P > 0.05). Immediate and DES protocols do not influence the hybrid layer formation, regardless of the bond strategy used. Conclusions: Sealing the pulp chamber dentin before endodontic treatment can improve the bond strength of the final restoration but the formation of the hybrid layer was not influenced by the bond strategy.

Antimicrobial action, cytotoxicity and erosive potential of hypochlorous acid obtained from an electrolytic device compared with sodium hypochlorite.

OBJECTIVES: This study aimed to compare the antimicrobial action, cytotoxicity, cleaning ability, and erosion of dentine of hypochlorous acid (HClO) obtained from an electrolytic device at two different concentrations (Dentaqua) and three concentrations of sodium hypochlorite (NaOCl). METHODS: Microbiological test-The root canals of sixty single-rooted extracted human teeth were inoculated with Enterococcus faecalis and divided into 6 groups (n = 10), according to decontamination protocol: DW (control); 1% NaOCl; 2.5% NaOCl; 5.25% NaOCl; 250 ppm HClO and 500 ppm HClO. The colony-forming units were counted to evaluate the decontamination potential of each group, calculating the reduction in bacterial percentage. Cytotoxicity test-Cytotoxicity was evaluated after inoculation of the same tested protocols in fibroblastic cells for 3 min, calculating the cell viability percentages. Specifical statistical analysis was performed (α = 5%). Cleaning ability and erosion-Fifty-six single-rooted bovine lower incisors were divided into seven groups of 8 roots each, being the test groups 1% NaOCl; 2.5% NaOCl; 5,25% NaOCl; 250 ppm HClO and 500 ppm HClO, and a negative and positive control. Negative control was not contaminated, and the other groups were inoculated with Enterococcus faecalis. SEM images were ranked as from the cleanest to the least clean. Erosion was also assessed, being ranked from the least to the most eroded dentine. RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences between them (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences between them (p < 0.05). 1% NaOCl; 2.5% NaOCl; 5.25% NaOCl and 500 ppm HClO displayed the cleanest areas. All sodium hypochlorite groups displayed erosion with higher ranks with greater concentration, while hypochlorous acid did not display any erosion regardless the concentration. CONCLUSIONS: It is possible to conclude that HClO obtained from an electrolytic device presented high antimicrobial activity and low cytotoxicity in both tested concentrations. 500 ppm HClO did not display erosion and showed great cleaning ability. CLINICAL RELEVANCE: The use of 500 ppm hypochlorous acid may reduce unfavorable behavior of sodium hypochlorite whilst maintaining its antimicrobial action.

Antimicrobial action and cytotoxicity of hypochlorous acid obtained from an innovative electrolytic device - An in vitro study.

OBJECTIVE: This study evaluated the antimicrobial effect and cytotoxicity of hypochlorous acid(HClO) obtained from an innovative electrolytic device. DESIGN: The root canals of fifty extracted human teeth were inoculated with Enterococcus faecalis and divided into 5 groups (n = 10): DW (control); 2% chlorhexidine gel(CHX); 2.5% sodium hypochlorite(NaOCl); 250 ppm HClO and 500 ppm HClO. The counting of colony forming units evaluated the decontamination potential of each group. Cytotoxicity was evaluated after inoculation of tested protocols in fibroblastic cells for 3 min, calculating the cell viability. Specific statistical analysis was performed (α = 5%). RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences from each other (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences from each other (p < 0.05). CONCLUSIONS: It could be concluded that HClO presented high antimicrobial activity and low cytotoxicity at both tested concentrations.

Tensile Strength and Elastic Modulus of Gutta-percha Cones Disinfected with Sodium Hypochlorite at Different Immersion Times: An In Vitro Comparative Study.

Aim: The tensile strength and modulus of elasticity of gutta-percha cones can be chemically altered due to disinfectant solutions. Therefore, the aim of the present study was to compare tensile strength and elastic modulus of gutta-percha cones subjected to sodium hypochlorite (NaOCl) disinfection at different times. Materials and Methods: This in vitro and longitudinal experimental study consisted of 45 gutta-percha cones, divided equally into three groups: Group 1 (disinfection with 2.5% NaOCl), Group 2 (disinfection with 5.25% NaOCl), and control group. All groups were subdivided according to immersion times for 1, 5, and 10 minutes. Tensile strength and elastic modulus were measured with a universal testing machine. For comparing more than two independent groups, parametric analysis of variance test with Sheffe's post hoc was used and for multivariate analysis, and multivariate analysis of variance test based on Pillai's Trace was used. In all statistical analysis, a significance level P ≤ 0.05 was considered. Results: When comparing the tensile strength of gutta-percha cones, no significant differences were observed after being immersed at 1, 5, and 10 minutes in NaOCl 2.5% (P = 0.715) and 5.25% (P = 0.585). Regarding the elastic modulus, a significant decrease (P < 0.05) was observed in those that were immersed in NaOCl 2.5% and 5.25% for 1, 5, and 10 minutes. Furthermore, increased NaOCl concentration significantly reduced the elastic modulus (P < 0.001). However, there were no significant differences in tensile strength (P > 0.05) and elastic modulus (P > 0.05), when evaluating the interaction between NaOCl concentration and time. Conclusion: Increasing NaOCl concentration significantly reduced the modulus of elasticity without affecting the tensile strength of gutta-percha cones, regardless of immersion time. Furthermore, the interaction of time and NaOCl concentration did not significantly affect the tensile strength and elastic modulus.

Spectrophotometric Analysis of Apical Extrusion of Sodium Hypochlorite using Different Irrigation Protocols in an Ex Vivo Model of Immature Teeth.

OBJECTIVE: To evaluate the effect of different agitation methods on apical extrusion of 1.5% sodium hypochlorite (NaOCl) in an ex vivo model of immature teeth. METHODS: Sixty extracted human inferior incisors were prepared to simulate immature teeth and embedded in an artificial root socket made of silicone impression material. The teeth were then divided into four groups: Conventional needle irrigation (CNI) alone, CNI supplemented with Ultrasonic Irrigant Activation (UIA), EasyClean (EC), or XP-endo Finisher (XPF). Extruded NaOCl was collected, reacted with m-cresol purple, and its absorbance values were measured. The data were statistically analyzed using One-way analysis of variance with a significance level of 5%. RESULTS: All groups showed apically extruded irrigating solution, and the mean volumes of extruded NaOCl did not differ significantly between any of the test groups (p⟩0.05). CONCLUSION: The activation of 1.5% NaOCL by UIA, EC, or XPF as supplementary to CNI does not promote greater apical extrusion when compared to CNI alone in simulated immature teeth.

Can the addition of surfactants to NaOCl irrigation impact on the percentage of voids of root canal filling?

This study evaluated the impact of canal irrigation using surfactants associated to NaOCl on the percentage of voids of root canal filling through micro-computed tomographic (micro-CT) analysis. 27 mandibular mesial roots with Vertucci type II canal configuration with isthmus were selected and scanned in a micro-CT device. The specimens were assigned to three groups (n = 9), according to the irrigation solution during instrumentation: 2.5% NaOCl without additives (control), 2.5% NaOCl with 0.1% Benzalkonium Chloride and 2.5% NaOCl with 0.1% Tween 80. After obturation, the specimens were rescanned, and the percentage of voids were calculated. Data were analysed using one-way ANOVA with a significance level of 5%. The percentage of voids were similar among the groups (p > 0.05). None of the specimens showed completely voids-free areas. The addition of surfactants to NaOCl irrigation did not improve the quality of root canal filling of mandibular mesial root canals.

Efficacy of calcium hypochlorite in disinfection of gutta-percha cones contaminated with Candida albicans.

This study aimed to compare the efficacy of 2.5% sodium hypochlorite (NaOCl), 2.5% calcium hypochlorite [Ca(OCl)2], and 2% chlorhexidine (CHX) in the rapid disinfection of gutta-percha cones contaminated with Candida albicans. The minimum inhibitory and minimum fungicidal concentrations of each solution for C. albicans were determined and the ability of each solution to destroy and inhibit biofilm in culture wells was tested. In addition, ninety-eight gutta-percha cones contaminated with the fungal suspension were disinfected according to the type of solution (2.5% NaOCl, 2.5% Ca(OCl)2 or 2% CHX) in its different application methods (without agitation, ultrasonic agitation or agitation with Easy Clean), and regarding the exposure time to each irrigating solution (1 or 5 min). Next, the samples were checked for turbidity and evaluation of viable colonies. The compounds that showed the best performance in biofilm destruction were NaOCl and Ca(OCl)2 at a concentration of 2xMIC (p < 0.001). Regarding inhibited biofilm, the only compound that was effective at all MIC concentrations tested was 2.5% Ca(OCl)2 (p < 0.0001). Regarding the viable colonies, all solutions were effective concerning the control group, for all application methods, in 1 and 5 min (p < 0.05). The densitometer reading showed that CHX was the only effective solution in all application methods performed (p < 0.05). The results demonstrate that all tested solutions were effective in the rapid decontamination of cones contaminated with C. albicans.

Research methods assessing sodium hypochlorite cytotoxicity: A scoping review.

Sodium hypochlorite (NaOCl) cytotoxicity has been assessed using different methodologies, which has led to arbitrary interpretations. This scoping review aimed to discuss the different methodological protocols for assessing NaOCl cytotoxicity. A literature review performed in the PubMed and Embase databases up to July 2023 identified manuscripts reporting NaOCl cytotoxicity. The dataset identified 546 publications, further screened by 2 reviewers. Ninety studies were identified and mined methodologically to collect information on cell type, cytotoxicity assay, NaOCl dilution solutions, presence of fetal bovine serum (FBS), and NaOCl exposure time. The culture medium used in cytotoxicity assays contains buffering substances that neutralize the pH of NaOCl, thus reducing its cytotoxicity, an approach that may lead to bias when solutions with different pH are compared. For short exposure periods, as in simulations to evaluate the contact between irrigant and periapical tissue cells during chemo-mechanical preparation, NaOCl dilution should be performed with saline, which does not buffer the irrigant. For long exposure periods, as in simulations of irrigant extrusions, NaOCl should be diluted in the culture medium, to reproduce the expected buffering effect occurring in extrusions. The presence of FBS in culture medium can decrease NaOCl toxicity. There is no standardization of NaOCl cytotoxicity methodologies. This poses the risk of arriving at incorrect results and, therefore, pertinent tests must be refined.

Knowledge about methods of disinfection of dental impression among dentists from Ecuador post SARS-COV-2 pandemic.

Purpose: The aim of this study is to evaluate the understanding of the management of methods and practices of disinfection of dental impressions applied by general dentists and specialists in oral rehabilitation, post SARS-COV-2 pandemic. Introduction: The oral cavity has a favorable environment for the growth and multiplication of bacteria and viruses, serving as the gateway to viruses such as SARS CoV-2 virus. Given that patients may be hosts of this infectious disease, stricter biosecurity measures in dental offices and a better understanding of the disinfection processes of dental impressions should be considered in addition to avoiding cross-infections, which are very common in our work environment. Materials and methods: Descriptive, analytical, survey with the topic "Methods and practices of disinfection of dental impressions" that was composed of 14 questions based in OHPD (Oral Health Preventive Dentistry), n = 452 respondents who met the following inclusion criteria: general practice dentists from Ecuador who actively take dental impressions, specialists in oral rehabilitation with 5 years of experience, surveys with information of complete items, n = 270 professionals; n = 192 general dentists, dental hygienist and n = 78 oral rehabilitation specialists. Results: n = 270 professionals evaluated, with a mean of p = 0.0. At 426 responses with a p value of <0.05, 30.4 % of responses indicated ignorance in the management of dental impressions, with a standard deviation of 2.744, with significant differences between professions (p = 0.035) and higher average knowledge of sample management within specialist dentists, (Chi p = 0.410 p > 0.05). Conclusion: The understanding of the management of dental impressions among general dentists and specialists in oral rehabilitation is limited.

Effect of two irrigating solutions on antimicrobial activity and clinical and radiographic success after endodontic treatment in primary teeth: a randomized clinical trial.

OBJECTIVES: This study evaluated the antimicrobial activity, clinical and radiographic outcome of pulpectomy in primary teeth using either 1% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) as irrigants. MATERIALS AND METHODS: A randomized double-blind controlled clinical study in which primary teeth were allocated to 1% NaOCl (n = 20) and 2% CHX (n = 20) groups. Microbiological collections were performed before and after irrigation for agar culture and real-time polymerase chain reaction (qPCR). Clinical and radiographic success was assessed at different times. Data were submitted to descriptive analysis, chi-square, Mann-Whitney, and Wilcoxon tests (p  < .05). RESULTS: For 1% NaOCl, the following clinical and radiographic success rates were observed: 7 days (93%/80%); 30 days, 3 and 6 months (100%). For 2% CHX: 7 days (73%/53%); 30 days (93%); 3 months (100%/93%); 6 months (100%) (p > .05). One percent NaOCl and 2% CHX effectively reduced total microorganisms (p < .05) but not mutans streptococci (p > .05). In qPCR analysis, the solutions promoted a reduction of total bacteria and Streptococcus mutans, and no difference was observed between times and groups (p > .05). CONCLUSIONS: One percent NaOCl and 2% CHX were effective for clinical and radiographic success and antimicrobial activity in primary teeth submitted to pulpectomy. CLINICAL RELEVANCE: Studying the antimicrobial activity and clinical and radiographic outcomes of pulpectomy in primary teeth using NaOCl and CHX as irrigants is clinically relevant because it provides information for optimizing treatment protocols and improving the quality of care for pediatric patients. It contributes to evidence-based practice and can potentially lead to better outcomes, reduced complications, and enhanced patient experiences.

Influence of the Use of Irrigation Solution Inhibitors in Improving Dentine Adhesion: A Systematic Review and Meta-Analysis.

INTRODUCTION: This systematic review examined the effect of neutralizing agents on bond strength after irrigation with sodium hypochlorite and their existing protocols in literature. METHODS: This present study adhered to the PRISMA guidelines and was registered at PROSPERO. Five electronic databases were searched (sept-2020/jan-2021) in English, Spanish, and Portuguese, without any restrictions on publication date. Cases reports, editorials and literature reviews were not included. The risk of bias was assessed using the Cochrane Collaboration tool. From the initial 7,147 studies, 2,745 were removed as duplicates and 4,382 were excluded after a title/abstract screen. RESULTS: Seventeen in vitro studies were included. The results showed that the higher the concentration of sodium hypochlorite, the lower the bond strength at dentine/restoration interface (p⟨0.01). Among the studies, sodium ascorbate was the most widely used neutralizer and showed the most significant results in increasing bond strength (p⟨0.01). The bond strength values were found to increase with longer application time of the neutralizing substances (p⟨0.01). CONCLUSIONS: The use of sodium ascorbate as a neutralizing agent can reverse the negative effects of the sodium hypochlorite and improve the bond strength between dentine and resin cement, however, it isn't possible to determine the best protocol for use.

Did in-between rinsing and agitating with distilled water prevents precipitate formation by the interaction between sodium hypochlorite and chlorhexidine canal irrigants?

The interaction of sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) produces an orange-brown precipitate. The present study evaluated the influence of distilled water (H2 O) in different irrigation protocols designed to prevent the formation of precipitate with NaOCl and CHX. Fifty canine teeth were instrumented and split longitudinally. The canal was examined with a stereomicroscope and photographed by canal-thirds. The tooth halves were repositioned and distributed randomly into five groups, according to the final irrigation protocol (n = 10): G1 (control)-Ethylenediaminetetraacetic acid (EDTA) + NaOCl + CHX, conventional irrigation (CI); G2-EDTA + NaOCl + CHX, activated with passive ultrasonic irrigation (PUI); G3-EDTA (PUI) + NaOCl (PUI) + H2 O (CI) + CHX (PUI); G4-EDTA + NaOCl + H2 O + CHX (PUI); G5-EDTA (PUI) + NaOCl (PUI) + H2 O (continuous ultrasonic irrigation [CUI]) + CHX (PUI). The specimens were evaluated with a stereomicroscope and scanning electron microscope (SEM). Energy dispersive x-ray spectroscopy analysis was performed to identify the elemental profile of the irrigated canal walls. The images were scored according to the extensiveness of precipitate. Data were analyzed (Kruskal-Wallis test, α = 5%). Under the stereomicroscope, G1 had significantly higher scores than all the other groups in all canal-thirds (p < .05). All four experimental groups showed similar scores (p > .05). There were no significant differences in precipitate formation among root-thirds in intragroup analysis (p > .05). Upon SEM examination, overall, only G5 had lower scores than G1 (p < .05). Analysis by canal-thirds showed no significant difference among groups and among canal-thirds in the intragroup analysis (p > .05). G1 showed high Cl peaks. In-between irrigation with H2 O activated by CUI is effective in preventing precipitate formation during canal debridement with NaOCl and CHX. RESEARCH HIGHLIGHTS: Continuous ultrasonic irrigation with distilled water was capable to prevent the precipitate formation. The precipitate can be classified as a chemical smear layer.

Antimicrobial Efficacy and Dentin Collagen Damage Caused by Calcium Hypochlorite and Sodium Hypochlorite

Abstract This study aimed to evaluate the antimicrobial activity of calcium hypochlorite (Ca (OCl)2) and sodium hypochlorite (NaOCl) using confocal laser scanning microscopy (CLSM) and dentin organic matrix alteration by picrosirius staining and light microscopy (LM). Samples of human extracted teeth were infected with Enterococcus faecalis by centrifugation of the bacterial suspension and were treated with Ca(OCl)2 or NaOCl at 0.5%, 2.5%, and 6% for 15, 30, and 60 seconds. CLSM and viability staining were used to quantitatively analyze the proportions of dead/live bacteria in the canal lumen and border of the root canal. The data were analyzed by ANOVA and Fisher test. For LM analysis, one hundred bovine teeth were randomly divided into 10 test groups (n=10): G1- Without treatment; G2- 17% EDTA; G3- 6% NaOCl; G4- 6% NaOCl + EDTA; G5- 0.5% Ca(OCl)2; G6- 0.5% Ca(OCl)2 + EDTA; G7- 2.5% Ca(OCl)2; G8- 2.5% Ca(OCl)2 + EDTA; G9- 6% Ca(OCl)2; G10- 6% Ca(OCl)2 + EDTA. The samples were fragmented and stained with Picrosirius. Data were analyzed by Kruskal-Wallis and Dunn (P<0.05). There was a strong correlation between the results of the canal lumen and the border of the root canal (r=0.962). Both hypochlorites at a concentration of 0.5% showed less microbial reduction compared to 2.5% and 6% (P<0.05). There was less antimicrobial activity at 15 seconds compared to 30 and 60 seconds (P<0.05). Ca(OCl)2 and NaOCl showed similar results at the same concentrations (P>0.05). In conclusion, Ca(OCl)2 caused fewer alterations to the dentin organic matrix at concentrations of 0.5% and 2.5%. Ca(OCl)2 presents antimicrobial activity similar to NaOCl, and collagen damage is concentration-dependent.

Resumo Este estudo teve como objetivo avaliar a atividade antimicrobiana do hipoclorito de cálcio (Ca(OCl)2) e do hipoclorito de sódio (NaOCl) usando a microscopia confocal a laser (MCVL) e a alteração da matriz orgânica da dentina por meio da coloração com picrosirius e microscopia óptica (MO). Amostras de dentes humanos extraídos foram infectados com Enterococcus faecalis por centrifugação da suspensão bacteriana. As amostras foram tratadas com Ca(OCl)2 ou NaOCl a 0,5%, 2,5% e 6% durante 15, 30 e 60 segundos. A MCVLe a coloração de viabilidade foram utilizadas para analisar quantitativamente as proporções de bactérias vivas/mortas no lúmen do canal e no bordo do canal radicular. Os dados foram analisados por ANOVA e teste de Fisher LSD. Para análise de MO, cem dentes bovinos foram divididos aleatoriamente em 10 grupos teste (n=10): G1- Sem tratamento; G2- 17% de EDTA; G3- 6% de NaOCl; G4- 6% de NaOCl + EDTA; G5- 0,5% de Ca(OCl)2; G6- 0,5% de Ca(OCl)2 + EDTA; G7- 2,5% de Ca(OCl)2; G8- 2,5% de Ca(OCl)2 + EDTA; G9- 6% de Ca(OCl)2; G10- 6% de Ca(OCl)2 + EDTA. As amostras foram fragmentadas e coradas com Picrosirius. Os dados foram analisados por Kruskal-Wallis e teste de Dunn (P<0,05). Houve uma forte correlação nos resultados do lúmen do canal e na borda do canal radicular (r=0,962). Ambos os hipocloritos, a uma concentração de 0,5%, mostraram menor redução microbiana em comparação com 2,5% e 6% (P<0,05). Houve menor atividade antimicrobiana aos 15 segundos em comparação com 30 e 60 segundos (P<0,05). Em conclusão, o Ca(OCl)2 e o NaOCl apresentaram resultados semelhantes nas mesmas concentrações (P>0,05). O Ca(OCl)2 causou menos alterações na matriz orgânica da dentina em concentrações de 0,5% e 2,5%. O Ca(OCl)2 apresenta atividade antimicrobiana semelhante ao NaOCl, e os danos ao colágeno dependem da concentraçã

Effect of sodium hypochlorite and calcium hypochlorite on the apical sealing ability of endodontic sealers

Aim: This study aimed to compare the influence of sodium hypochlorite (NaOCl) and calcium hypochlorite [Ca(OCl)2 ] on the apical sealing capacity of AH Plus (Dentsply Maillefer) and Bio-C Sealer (Angelus) endodontic sealers. Methods: Sixty permanent human lower incisors were randomly allocated (http://www.randomized.org), according to the irrigant used, into three groups (n=20): 0.9% sodium chloride (NaCl/Control); 2.5% NaOCl; and 2.5% Ca(OCl)2 . The root canal was prepared with rotary files under 10 mL of the solution corresponding to the experimental group. Each group was subdivided into two (n=10) according to the sealer used for filling: AH Plus (Dentsply Maillefer) or Bio-C Sealer (Angelus). Then, all samples were immersed in black India ink for one week. After the storage period, the roots were then grooved longitudinally and split, and the ink penetration was measured from the apical part to the coronal part of the root canal into which the ink penetrated using a stereomicroscope. Data were analyzed by one-way ANOVA and Tukey's post-hoc tests. Results: There was no statistical difference in ink penetration between the different endodontic sealers tested for the same irrigating solution (p > 0.05). However, when the Bio-C Sealer (Angelus) was used, the group treated with 2.5% Ca(OCl)2 was associated with lower values of apical leakage, compared to 2.5% NaOCl (p < 0.05). For the AH Plus sealer (Dentsply Maillefer), there was no difference between the irrigants (p > 0.05). Conclusions: Associating Ca(OCl)2 irrigant with Bio-C Sealer (Angelus) seems to be a good option to reduce apical leakage

Accuracy of the integrated electronic apex locator in locating simulated perforation under various irrigating solutions in an in vitro study

Aim: This study's objective was to assess the accuracy of the integrated apex locator in identifying artificial root canal perforations in the presence of saline, chlorhexidine, sodium hypochlorite, QMix, and MTAD. Methods: The root canals of 60 single-rooted extracted human teeth were perforated artificially at a point 10 mm away from the root apex. After measuring the actual lengths up to the perforation point, the teeth were then put within an alginate mould for measurements using an integrated apex locator. Using a #20 K-file in the presence of NaCl, CHX, MTAD, NaOCl, and QMix, an electronic apex locator was used to measure the perforations electronically in accordance with the manufacturer's instructions. Between the measurements, each canal was dried with paper points after being irrigated with distilled water. The accuracy of all the readings was calculated at ± 0.5 mm. Statistical analyses were performed using the Z-test. Results: In comparison to the MTAD, NaOCl, and Qmix, saline and chlorhexidine scored more readings in the ± 0.5 mm range of the perforation site, and the difference was statistically significant. Conclusion: The most precise electronic measurements of artificial perforation were obtained in the presence of chlorhexidine or saline