Efficacy of mixed diclofenac solutions against root canal biofilms.

The objective of this research was to evaluate the efficacy of diclofenac sodium solutions, with or without cetrimide (CTR) added, against polymicrobial root canal biofilms grown in dentin specimens. The study groups were: (1) 5% diclofenac sodium (DCS); (2) 2.5% DCS; (3) 2.5% DCS + 0. 2% CTR; (4) 2.5% DCS + 0.4% CTR and (5) 0.9% saline solution (SS) as the control. After 5 min of solution contact with the biofilms, the antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay as well as confocal laser scanning microscopy (CLSM). Microbial quantification was indicated as the percentage reduction of relative light units (RLUs) for the ATP assay, the Log10 total biovolume and the viability percentage (green cells) for CLSM. Solutions of 2.5% DCS + 0.4% CTR and 5% DCS showed the highest antimicrobial efficacy. Cetrimide increased the antibiofilm activity of diclofenac sodium against endodontic biofilms.

Effectiveness of conservative instrumentation in root canal disinfection.

OBJECTIVES: The impact of conservative instrumentation on the disinfection of root canals with different curvatures has not yet been determined. This ex vivo study aimed to evaluate and compare the effect of conservative instrumentation with TruNatomy (TN) and Rotate and a conventional rotary system, ProTaper Gold (PTG), on root canal disinfection during chemomechanical preparation of straight and curved canals. MATERIALS AND METHODS: Ninety mandibular molars with straight (n = 45) and curved (n = 45) mesiobuccal root canals were contaminated with polymicrobial clinical samples. Teeth were divided into three subgroups (n = 14) according to the file systems and the curvature. Canals were instrumented with TN, Rotate, and PTG, respectively. Sodium hypochlorite and EDTA were used as irrigants. Intracanal samples were taken before (S1) and after (S2) instrumentation. Six uninfected teeth were used as negative controls. The bacterial reduction between S1 and S2 was measured by ATP assay, flow cytometry, and culture methods. Kruskal-Wallis and ANOVA tests were followed by the Duncan post hoc test (p < 0.05). RESULTS: Bacterial reduction percentages were similar for the three file systems in straight canals (p > 0.05). However, PTG showed a lower reduction percentage of intact membrane cells in flow cytometry than TN and Rotate (p = 0.036). For the curved canals, no significant differences were obtained (p > 0.05). CONCLUSION: Conservative instrumentation of straight and curved canals using TN and Rotate files resulted in similar bacterial reduction compared to PTG. CLINICAL RELEVANCE: The disinfection efficacy of conservative instrumentation is similar to conventional instrumentation in straight and curved root canals.

Antimicrobial Activity and Cytotoxicity of Nonsteroidal Anti-Inflammatory Drugs against Endodontic Biofilms.

Persistent infections have become a challenge in dentistry because of growing antibiotic resistance. Nonsteroidal anti-inflammatory drugs (NSAIDs) appear to be a therapeutic alternative to control biofilm infection. The objective of this work is to evaluate the antimicrobial activity and cytotoxicity of sodium diclofenac (DCS), ibuprofen (IBP) and ibuprofen arginine (IBP-arginine) solutions against endodontic polymicrobial biofilms. Sterile radicular dentin blocks of 4 mm × 4 mm × 0.7 mm were used as substrate to grow biofilm. The dentin blocks were submerged into solutions for 5 min. The antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay and confocal laser scanning microscopy (CLSM). Fibroblasts 3T3-L1 (ECACC 86052701) were used to test the cytotoxicity of irrigating solutions. The antibiofilm effects determined by the ATP assay showed that 4% IBP-arginine solution exerted the highest antibiofilm activity, followed by 4% DCS and 4% IBP, with statistical differences among groups (p < 0.001). As for CLSM, 4% DCS and 4% IBP-arginine solutions gave the lowest viable cell percentages, without significant differences between them. Cytotoxicity results at 1/10 dilution were similar for all solutions. At 1/100 dilution, a 4% DCS solution obtained the lowest cell viability for both time periods assayed, 1 h and 24 h. The IBP-arginine group showed the highest cell viability at 24 h. In this preliminary study, in terms of antibiofilm activity and cytotoxicity, a mixed 4% IBP-arginine solution gave the most promising results. NSAID solutions could be recommendable drugs for endodontic disinfection procedures.

Antimicrobial potential of new diclofenac hydrogels for disinfection in regenerative endodontics: An in vitro and ex vivo study.

AIM: There is a need to explore new alternatives for root canal disinfection in regenerative endodontics, since the current strategies are far from ideal. Currently, the potential use of diclofenac (DC) is being investigated for controlling root canal infections. The objective was to evaluate the antimicrobial efficacy of novel DC-based hydrogels (DCHs) against polymicrobial biofilms grown in radicular dentine and root canals and to compare results with triantibiotic (TAH) and diantibiotic (DAH) hydrogels, and calcium hydroxide (Ca[OH]2 ). METHODOLOGY: The in vitro antimicrobial activity of intracanal medicaments was evaluated against 3-week-old polymicrobial root canal biofilms grown on human radicular dentine. Dentine samples were obtained and randomly divided into the study groups (n = 4/group): (1) 1 mg/ml TAH; (2) 1 mg/ml DAH; (3) 5% diclofenac (DCH); (4) 2.5% DCH; (5) 1.25% DCH; (6) 1 mg/ml DAH + 5% DCH; (7) Ca(OH)2 paste; (8) positive control. The microbial viability, in terms of percentage of intact cell membranes, was assessed after 7 days by confocal scanning laser microscopy (CSLM). The ex vivo efficacy of intracanal medications was evaluated in root canals infected with a polymicrobial suspension. Intracanal microbiological samples at baseline (S1) and 7 days post-treatment (S2) were taken; microbial quantification and cell viability were assessed by quantitative polymerase chain reaction (qPCR) and flow cytometry (FC). The mean Log10 of bacterial DNA copies in root canal samples before (S1) and the Log10 reduction of DNA copies S1-S2 in qPCR were recorded. The absolute value of total cells stained, and the percentage reduction of intact membrane cells after treatment (S1-S2), were analysed by FC. Global comparison was done using the Kruskal-Wallis test, whilst the Mann-Whitney U test was used for pair-by-pair comparison. RESULTS: Confocal scanning laser microscopy analysis indicated that the greatest effectiveness was obtained with 5% DCH, showing significant differences with respect to the other groups (p < .001). In root canals, the highest Log10 DNA reduction S1-S2 was obtained with 5% DCH and TAH, with no differences between them. The results of FC showed that only 5% DCH proved significantly superior to the other treatments. CONCLUSIONS: Sodium DC hydrogels demonstrate antimicrobial efficacy against endodontic biofilms.

Root Canal Disinfection Articles with the Highest Relative Citation Ratios. A Bibliometric Analysis from 1990 to 2019.

The relative citation rate (RCR) is a normalized article-level metric useful to assess the impact of research articles. The objective of this bibliometric study is to identify and analyze, in root canal disinfection, the 100 articles having the highest RCRs in the period 1990-2019, then compare them with the top 100 articles most cited. A cross-sectional study was performed, and the search strategy ((Disinfection AND root canal) AND (("1990/01/01"[Date-Publication]: "2019/12/31"[Date-Publication]))) relied on PubMed (n = 4294 documents), and article data were downloaded from the iCite database. The 100 articles with the highest RCRs and the top 100 cited were selected and evaluated in bibliometric terms. Among the 100 articles with the highest RCRs, there were no differences in the three decades for RCRs values, but there were in citations, being 2000-2009 the most cited. The USA was the predominant country (n = 30), followed by Brazil (n = 14). The most frequent study designs were reviews (n = 27) and in vitro (n = 25) and ex vivo (n = 24) studies. All subfields were well represented, although they varied over time. In 2010-2019, regenerative procedures and irrigation/disinfection techniques were predominant. Considering the RCR's top 100 articles, 76 were common with the 100 most cited articles. Using the RCR metric allowed us to identify influential articles in root canal disinfection, a research field with topics of significance that fluctuate over time. Compared to citations, RCR reduces the time from publication to detection of its importance for the readership and could be a valid alternative to citation counts.

Antibiofilm Activity of Diclofenac and Antibiotic Solutions in Endodontic Therapy.

INTRODUCTION: The aim of this study was to compare the antibiofilm effects of a triple antibiotic solution (TAS); a double antibiotic solution (DAS); and 5%, 2.5%, and 1.25% diclofenac solutions (DCSs) against Enteroccocus faecalis biofilm. METHODS: Eighty-four sterile radicular dentin blocks were used as biofilm substrate for 3 weeks. The study groups were as follows: (1) 1 mg/mL TAS (minocycline, metronidazole, and ciprofloxacin), (2) 1 mg/mL DAS (metronidazole and ciprofloxacin), (3) 5% DCS, (4) 2.5% DCS, (5) 1.25% DCS, and (6) 0.9% saline solution. The antimicrobial activity was evaluated by bacterial count determinations and confocal laser scanning microscopy. The contact time for the antimicrobial tests was 5 minutes. Bacterial counts were expressed as the reduction percentage of colony-forming units; for the confocal laser scanning microscopic evaluation, the log10 total biovolume and percentage of green population (live cells) were calculated. RESULTS: The colony-forming unit reduction percentage ranged between 62.98 and 98.62, respectively, for TAS and 5% DCS. The DCS showed a concentration-dependent effect.For the confocal laser scanning microscopy, the log10 total biovolume in all groups was very similar and showed a scarce (1.39-1.02) but significant reduction with respect to the control; 5% and 2.5% DCSs gave the lowest viable cell percentage. The TAS and DAS groups showed intermediate values without significant differences between them. CONCLUSIONS: DCSs at 5% and 2.5% have greater antimicrobial effects than TAS and DAS and may be considered a valid alternative for controlling the infection of teeth with apical periodontitis.

Antibacterial and antibiofilm activity over time of GuttaFlow Bioseal and AH Plus.

The sealers' antibacterial and antibiofilm activities against Enterococcus faecalis were evaluated by direct contact test (DCT) and confocal laser scanning microscopy (CLSM), respectively, after 1 day, and 1 and 4 weeks of aging. Cell viability was determined by adenosin triphosphate (ATP) assay after DCT. The parameters evaluated for the antibiofilm property were total biovolume and percentage of green cells in E.faecalis biofilms. The data from the bioluminescence ATP assay as well as the total biovolume and green percentage were analyzed by non-parametric tests, Kruskal-Wallis for global comparison and Kolmogorov-Smirnov for each two variables. Results of the DCT and CLSM for all parameters evaluated show that the antimicrobial activity of AH Plus decreased over time, whereas GuttaFlow Bioseal had an opposite property, increasing its antibacterial activity as the material aged.

Dentine tubule disinfection by different irrigation protocols.

The purpose of this study was to test the antimicrobial activity and the smear layer removal of different irrigation protocols-sodium hypochlorite (NaOCl), NaOCl followed by ethylenediaminetetraacetic acid (EDTA), and NaOCl combined with etidronic acid (HEBP)-against infected dentine tubules during root canal preparation. Single rooted premolars contaminated with Enterococcus faecalis were chemomechanically prepared. Depending on the irrigation protocols, the roots were divided into the following groups: (1) distilled water during and after instrumentation; (2) 2.5% NaOCl during and after instrumentation; (3) 2.5% NaOCl/9% HEBP during and after instrumentation; and (4) 2.5% NaOCl during instrumentation followed by 17% EDTA after instrumentation. The percentage of dead cells and the biovolume in infected dentine tubules were measured using confocal laser scanning microscopy and the live/dead technique. Smear layer removal on root canal wall surfaces was observed by means of scanning electron microscopy. Results were compared through parametric tests (p < .05). The groups NaOCl, NaOCl/HEBP, and NaOCl+EDTA exerted the highest antimicrobial activity (p > .05), followed by the group irrigated with water. All the irrigation protocols-including water-significantly reduced the bacteria biovolume. No dentine tubules free of smear layer were found in the positive control or the 2.5% NaOCl group. With NaOCl/HEBP and NaOCl+EDTA, respectively, 90.41% ± 7.33 and 76.54% ± 15.30 of dentine tubules were free of smear layer (p = .01). NaOCl/HEBP and NaOCl+EDTA exerted an important antimicrobial activity against bacteria inside dentine tubules, lowering the bacteria biovolume and eliminating a high amount of the smear layer, particularly in the NaOCl/HEBP group.

Evaluation of final irrigation regimens with maleic acid for smear layer removal and wettability of root canal sealer.

OBJECTIVE: To evaluate the smear layer removal and wettability of AH Plus sealer on root canal dentin treated with MA (maleic acid), MA + CTR (cetrimide) and MA + CTR + CHX (chlorhexidine) as final irrigating regimens. MATERIAL AND METHODS: For smear layer removal, 40 teeth were instrumented to size F4 and divided into four groups: (1) 7% MA, (2) 7% MA + 0.2% CTR, (3) 7% MA + 0.2% CTR + 2% CHX, (4) distilled water (control). After irrigation, teeth were subjected to SEM analysis. For contact angle analysis, 20 teeth were split longitudinally and divided into four groups similar to smear layer analysis. AH plus sealer was placed on each specimen and contact angle was analysed. RESULTS: In both smear layer (p = .393) and contact angle analysis (p = .961), there was no significant difference between the groups MA and MA + CTR. However, MA + CTR + CHX removed smear layer less effectively (p = .023) and increased the contact angle of the sealer (p = .005). In smear layer analysis, specimens in negative control group were heavily smeared. In case of contact angle analysis, samples in the control group had least contact angle. CONCLUSION: MA alone or in combination with CTR removed smear layer effectively and increased the wettability of AH plus sealer to root canal dentin.

Antibiofilm Activity of Sodium Hypochlorite and Alkaline Tetrasodium EDTA Solutions.

INTRODUCTION: The aim of this study was to determine the antimicrobial activity of mixed alkaline tetrasodium EDTA (EDTANa4)/sodium hypochlorite (NaOCl) solutions with and without the addition of cetrimide (CTR) against Enterococcus faecalis biofilms. METHODS: The antimicrobial solutions were evaluated on a 3-week biofilm of E. faecalis grown on radicular dentin blocks. The irrigating solutions were 2.5% NaOCl group, 20% EDTANa4 group, 10% EDTANa4 group, 2.5% NaOCl/10% EDTANa4 group, 2.5% NaOCl/5% EDTANa4 group, 2.5% NaOCl/10% EDTANa4/0.2% CTR group, 2.5% NaOCl/5% EDTANa4/0.2% CTR group, and 0.9% saline solution group. Cell viability was determined by adenosine triphosphate assay, and culture techniques were used to determine colony-forming unit (CFU) counts. In groups with positive growth, the Pearson linear correlation coefficient r (-1 ≤ r ≤ 1) between relative light units (RLUs) and log10 (CFUs + 1) was calculated. The results of the bioluminescence adenosine triphosphate assay and CFUs of the groups were analyzed by means of analysis of variance and the Duncan test. RESULTS: There was Pearson correlation between RLUs and log10 (CFUs + 1). A similar reduction of RLUs in all NaOCl groups was seen, giving statistical differences with respect to the control. In the NaOCl groups there was no bacterial growth. The lowest antimicrobial efficacy was found for the EDTANa4 groups. CONCLUSIONS: Mixed alkaline EDTANa4/NaOCl solutions with and without the addition of CTR do not interfere with the antimicrobial activity of NaOCl.

Cone-beam Computed Tomographic Study of Root Anatomy and Canal Configuration of Molars in a Spanish Population.

INTRODUCTION: The aim of this study was to identify morphologic peculiarities of roots and analyze the root canal configuration in maxillary and mandibular first and second molars by means using cone-beam computed tomographic (CBCT) imaging in a Spanish population. METHODS: A total of 284 maxillary molars and 242 mandibular molars from 112 patients were examined in vivo by CBCT imaging; only untreated molars with healthy and fully matured apices were included in this study. Details regarding the number of roots, number of canals, and root canal configuration were recorded. RESULTS: Maxillary first and second molars had 3 roots in 97.2% and 79%, respectively. In mandibular molars, the frequency of 2 roots was 94% in first molars and 83% in second molars. The canal configuration of the palatal root was 100% Vertucci type I (1-1) in first and second molars. The distobuccal root showed a Vertucci type I configuration in 97% of first and 100% of maxillary second molars. The mesiobuccal root for first molars showed a Vertucci type II configuration (2-1) in 56.5% cases and Vertucci type IV (2-2) in 23.2%. For maxillary second molars, the Vertucci type I configuration reached 52.7%. In mandibular molars, the mesial root showed higher variability. Most frequent was the presence of 2 canals, Vertucci type II for first and second molars. In the distal root, the most common configuration was Vertucci type I in both molars. CONCLUSIONS: The greater percentage of fused roots was observed in maxillary molars. Vertucci type II configuration was more frequent than type IV in the mesial root of mandibular molars and the mesiobuccal root of maxillary molars. A third canal in the mesial root of first mandibular molars (6.7%) was higher than expected.

Antibacterial efficacy of several intracanal medicaments for endodontic therapy.

The antibacterial efficacy of intracanal medicaments for 2 and 7 days, in open apex root canals contaminated with Enterococcus faecalis biofilms was compared. One hundred and thirty-eight standardized uniradicular human roots were inoculated with E. faecalis. Colony forming units (CFU) were recorded before and after medication. Samples were divided in two (2/7 days), and subdivided (n=8/group): triple antibiotic paste (TAP); double antibiotic paste (DAP); dental base paste (DBP), consisting of calcium hydroxide, propylene glycol and calcium carbonate; DBP+0.2% chlorhexidine (CHX); DBP+0.2% cetrimide (CTR); DBP+0.2% CHX+0.2% CTR; 2.5% sodium hypochlorite (NaOCl); and distilled water. At both periods TAP, DAP, DBP+0.2% CHX, DBP+0.2% CTR and DBP+0.2% CHX+0.2% CTR exhibited no growth (NG) of E. faecalis. Distilled water and 2.5% NaOCl obtained the lowest CFU reduction. No growth with DBP was reached only at 7 days. CHX and/or CTR pastes were as effective as DAP and TAP. A 2-day period provided an effective disinfection.

Influence of Smear Layer on the Antimicrobial Activity of a Sodium Hypochlorite/Etidronic Acid Irrigating Solution in Infected Dentin.

INTRODUCTION: The aim of this study was to evaluate the influence of the smear layer on the antimicrobial activity of a 2.5% sodium hypochlorite (NaOCl)/9% etidronic acid (HEBP) irrigating solution against bacteria growing inside dentin tubules. METHODS: Dentin tubules were infected with Enterococcus faecalis by centrifugation. After 5 days of incubation, the smear layer had formed in half of the samples, which were then treated with 2.5% NaOCl either alone or combined with 9% HEBP for 3 minutes. The percentage of dead cells in infected dentinal tubules was measured using confocal laser scanning microscopy and the live/dead technique. The smear layer on the surface of the root canal wall was also observed by scanning electron microscopy. Results of the percentage of dead cells were compared using parametric tests after subjecting data to the normalized Anscombe transformation. The level of significance was P < .05. RESULTS: In the absence of the smear layer, 2.5% NaOCl alone and combined with 9% HEBP showed high antimicrobial activity without significant differences between the 2. The smear layer reduced the antimicrobial activity of 2.5% NaOCl significantly, whereas the solution with HEBP was not affected. No dentin tubules free of the smear layer were obtained in the 2.5% NaOCl group. In the case of 2.5% NaOCl/9% HEBP, 95.40% ± 3.63% of dentin tubules were cleaned. CONCLUSIONS: The presence of the smear layer reduced the antimicrobial activity of 2.5% NaOCl. The combination of 2.5% NaOCl/9% HEBP exerted antimicrobial activity that was not reduced by the smear layer.

Effects of Dentin Debris on the Antimicrobial Properties of Sodium Hypochlorite and Etidronic Acid.

INTRODUCTION: The purpose of this study was to determine the influence of dentin powder on the concentration, pH, and antimicrobial activity of sodium hypochlorite (NaOCl) alone and combined with etidronic acid (HEBP). METHODS: Biofilms of Enterococcus faecalis were grown on the surface of dentin blocks for 5 days and then exposed to 1% and 2.5% NaOCl alone or combined with 9% HEBP for 3 minutes in the absence and presence of dentin powder. The biovolumes of the biofilm were measured using confocal microscopy and the live/dead technique. The available chlorine and pH of the solutions were also measured. Nonparametric tests were used to determine statistical differences (P < .05). RESULTS: The presence of dentin powder resulted in a reduction of the free available chlorine and pH in all the irrigating solutions; 1% NaOCl lost its antimicrobial activity completely in the presence of dentin powder. The antimicrobial activity was significantly reduced in the 2.5% NaOCl and 1% NaOCl/HEBP groups, and it was not affected in the 2.5% NaOCl/HEBP group. CONCLUSIONS: The presence of dentin powder significantly decreased the available chlorine and antimicrobial activity of 1% NaOCl, 2.5% NaOCl, and 1% NaOCl/HEBP irrigating solutions. The antimicrobial activity of 2.5% NaOCl/HEBP was not affected by the dentin powder after a 3-minute contact time against E. faecalis biofilms.

Antimicrobial residual effects of irrigation regimens with maleic acid in infected root canals.

BACKGROUND: The success of endodontic treatment depends largely on the control of microorganisms present in infected root canals. The aim of this study was to determine the residual antimicrobial activity of several final irrigation protocols with 7% maleic acid (MA) alone and combined with chlorhexidine (CHX), cetrimide (CTR) or both, in root canals infected with Enterococcus faecalis. Biofilms of E. faecalis were grown in uniradicular roots for 4 weeks. A total of 72 specimens were divided into 5 experimental groups according to the final irrigation regime used: Group 1: 2.5% NaOCl; Group 2: 7% MA; Group 3: 7% MA + 0.2% CTR; Group 4: 7% MA + 2% CHX; Group 5: 7% MA + 0.2% CTR + 2% CHX; and CONTROL GROUP: 0.9% saline solution. Twelve roots (2/group) that were instrumented and not infected served as negative or sterility controls. The proportion of ungrown samples over 60 days was evaluated using non-parametric Kaplan-Meier survival analysis. Differences among groups were tested using the log-rank test (p< 0.05). RESULTS: The association of MA with CHX and CHX + CTR as final irrigating solutions showed the best results, 5 and 4 samples out of 12, respectively, and without differences between them (p = 0.928), followed by 7% MA + 0.2% CTR with 7 out of 12. The 7% MA (11/12) group showed significant differences with respect to the groups in which MA was combined with CHX (p < 0.005) and CHX + CTR (p < 0.005). CONCLUSION: Final irrigating solutions of 7% MA combined with 2% CHX or 2% CHX + 0.2% CTR were found to effectively improve antimicrobial root canal disinfection.

Antimicrobial activity of a sodium hypochlorite/etidronic acid irrigant solution.

INTRODUCTION: The aim of this study was to evaluate the antimicrobial activity of a 2.5% sodium hypochlorite (NaOCl)/9% etidronic acid (HEBP) irrigant solution on Enterococcus faecalis growing in biofilms and a dentinal tubule infection model. METHODS: The antimicrobial activity of the solutions 2.5% NaOCl and 9% HEBP alone and associated was evaluated on E. faecalis biofilms grown in the Calgary biofilm model (minimum biofilm eradication concentration high-throughput device). For the dentinal tubule infection test, the percentage of dead cells in E. faecalis-infected dentinal tubules treated with the solutions for 10 minutes was measured using confocal laser scanning microscopy and the live/dead technique. Available chlorine and pH of the solutions were also measured. Distilled water was used as the control. Nonparametric tests were used to determine statistical differences. RESULTS: The highest viability was found in the distilled water group and the lowest in the NaOCl-treated dentin (P < .05). Both NaOCl solutions killed 100% of the E. faecalis biofilms and showed the highest antimicrobial activity inside dentinal tubules, without statistical differences between the 2 (P < .05). The HEBP isolated solution killed bacteria inside dentinal tubules but did not present any significant effect against E. faecalis biofilms. The incorporation of HEBP to NaOCl did not cause any loss of available chlorine within 60 minutes. CONCLUSIONS: HEBP did not interfere with the ability of NaOCl to kill E. faecalis grown in biofilms and inside dentinal tubules.

Antimicrobial activity of alexidine, chlorhexidine and cetrimide against Streptococcus mutans biofilm.

BACKGROUND: The use of antimicrobial solutions has been recommended to disinfect demineralized dentin prior to placing the filling material. The aim of this study was to evaluate the ability of several antimicrobials in controlling Streptococcus mutans (SM) biofilm formed in dentin. METHODS: Antimicrobial activity of 0.2% and 2% chlorhexidine (CHX), 0.2% cetrimide (CTR) and 0.2%, 0.5%, 1% and 2% alexidine (ALX) was assayed on 1-week SM biofilm formed on standardized coronal dentin blocks. Results of SM biofilm antimicrobial activity by different protocols were expressed as the kill percentage of biofilm and the term "eradication" was used to denote the kill of 100% of the bacterial population. To compare the efficacies of the different protocols the Student t test was used, previously subjecting data to the Anscombe transformation. RESULTS: All ALX concentrations tested and 0.2% CTR achieved a kill percentage higher than 99%, followed by 2% CHX with percentages above 96% (no statistically significant difference among them). Whereas 2% ALX and 0.2% CTR respectively showed eradication in 10 and 9 of the twelve specimens, 0.2% CHX did not produce eradication in any case. CONCLUSIONS: The present study shows that, when used for one minute, 2% and 1% alexidine, and 0.2% cetrimide, achieve eradication of Streptococcus mutans biofilm in most specimens when applied to a dentin-volumetric model.

Antibacterial and anti-biofilm activity of AH plus with chlorhexidine and cetrimide.

INTRODUCTION: The use of root canal filling materials with antibacterial activity can be considered beneficial to reduce the remaining microorganisms in the root canal system, where Enterococcus faecalis is often found, and prevent recurrent infection. The aim of this study was to evaluate the antimicrobial activity and capacity for inhibiting E. faecalis biofilm formation of AH Plus, alone and mixed with chlorhexidine (CHX), cetrimide (CTR), and combinations of the two. METHODS: AH Plus alone and mixed with 1% and 2% CHX, 0.1%-0.5% CTR, and combinations of both were tested to assess antimicrobial activity by a modified direct contact test and determine inhibition of E. faecalis biofilm formation at 24 hours. The results were expressed as log10 viable counts. Eradication and inhibition of biofilm formation were understood as no bacterial growth or log10 reduction = 5 with respect to the control (AH Plus alone). RESULTS: AH Plus + CHX showed a low antimicrobial activity with respect to the control (at 2%, log10 reduction = 1.30). None of the tested concentrations achieved eradication or inhibition of biofilm. AH Plus + CTR showed a direct relationship of concentration-antimicrobial effect, reaching a log10 reduction of 2.92 at 0.5% and inhibition of biofilm formation at 0.2%. With the combination CHX + CTR, lower concentrations were needed for the same effect, and eradication and inhibition of biofilm were achieved. CONCLUSIONS: The addition of CHX, CTR, or some combination of both to AH Plus confers it with bactericidal and anti-biofilm activity against E. faecalis.

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents.

OBJECTIVE: The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE; (2) Excite DSC; (3) Clearfil Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test. RESULTS: At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil Protect Bond, AdheSE and Excite DSC showed similar behaviours, likewise similar to the Control group. CONCLUSIONS: One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.

Physical properties of AH Plus with chlorhexidine and cetrimide.

INTRODUCTION: The use of root canal filling materials with antibacterial activity could be considered beneficial to reduce any remaining microorganisms and prevent recurrent infection. The aim of this study was to evaluate the physical properties of AH Plus (Dentsply DeTrey, Konstanz, Germany) alone and mixed with 1% or 2% chlorhexidine (CHX); 0.1%, 0.2%, 0.3%, and 0.5% of cetrimide (CTR); and combinations of both. METHODS: Setting time, flow, solubility, and radiopacity of AH Plus and modified AH Plus were evaluated following the American National Standards Institute/American Dental Association's requirements (ANSI/ADA Specification No. 57/2000). Five samples of each material were tested for each property. The hypothesis of equality among groups was rejected by an analysis of variance test, and then a post hoc Tukey test was performed. RESULTS: AH Plus and modified AH Plus gave values that are within the required standards. Overall, results indicate that CTR increased setting time, but CHX alone and CHX + CTR reduced it. CHX increased the flow, whereas CTR reduced it, and their combinations gave intermediate values comparable with those of AH Plus. Concerning solubility, the weight loss in all samples was under the 3% limit set by the ANSI/ADA. In comparison with AH Plus alone, radiopacity gave slightly lower values with CHX, higher values with CTR, and similar values with combinations. CONCLUSIONS: The addition of CHX, CTR, and combinations of both to AH Plus did not alter the physical properties specified by ANSI/ADA requirements.