In vitro assessment of the immediate and prolonged antimicrobial action of chlorhexidine gel as an endodontic irrigant against Enterococcus faecalis.

OBJECTIVE: The aim of this study was to assess in vitro the antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis , comparing it to other endodontic irrigants (2% chlorhexidine liquid and 5.25% sodium hypochlorite). STUDY DESIGN: Eighty roots of human mandibular premolars were prepared by serial instrumentation technique, autoclaved, and contaminated for 7 days with E faecalis monocultures. The roots were then divided into 5 groups according to the irrigant substance used during the standardized biomechanical preparation. In order to evaluate the antimicrobial action of the irrigant substances, 3 microbial samples were taken: initial (before the biomechanical preparation); post-treatment (immediately after the biomechanical preparation), and final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU). RESULTS: The 2% chlorhexidine gel and 2% chlorhexidine liquid significantly reduced the E faecalis CFU in the post-treatment and final microbiological samples. The 5.25% sodium hypochlorite also reduced the E faecalis CFU immediately after the root canal instrumentation, but it was not able to keep the root canal free of detectable E faecalis in the final sample. CONCLUSIONS: The 2% chlorhexidine gluconate (gel and liquid) antimicrobial ability was more effective than 5.25% sodium hypochlorite in keeping low CFU of E faecalis for 7 days after the biomechanical preparation.     

In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament.

The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water.     

In vitro antibacterial efficacy of endodontic irrigants against Enterococcus faecalis.

OBJECTIVE: The objective of this study was to compare the in vitro antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis with sodium hypochlorite in 2 different concentrations (1.5% and 5.25%). STUDY DESIGN: Eighty human lower premolars with single root canals were prepared, autoclaved, and infected for 7 days with E. faecalis monocultures. The roots were then separated into 5 experimental groups according to the irrigant solution used during the standardized preparation. To assess the antimicrobial action of the irrigant solutions, 3 microbial samples were taken: S1--initial (before the biomechanical preparation), S2--posttreatment (immediately after the biomechanical preparation), and S3--final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU). RESULTS: The 2% chlorhexidine gel and 5.25% sodium hypochlorite significantly reduced the E. faecalis CFU in the posttreatment and final microbiological samples. The 1.5% sodium hypochlorite also reduced the E. faecalis CFU immediately after the root canal instrumentation, but the E. faecalis CFU increased in the final sample showing no statistical difference from the control group. CONCLUSION: The 2% chlorhexidine gluconate gel and 5.25% sodium hypochlorite were effective in eliminating E. faecalis even 7 days after the instrumentation; moreover, the higher the concentration of sodium hypochlorite the better its antimicrobial action.     

Effectiveness of ozonated water on Candida albicans, Enterococcus faecalis, and endotoxins in root canals.

The aim of this study was to evaluate the effectiveness of ozonated water in the elimination of Candida albicans, Enterococcus faecalis, and endotoxins from root canals. Twenty-four single-rooted human teeth were inoculated with C. albicans and E. faecalis, and 24 specimens were inoculated with Escherichia coli endotoxin. Ozonated water (experimental group) or physiologic solution (control group) was used as irrigant agent. Antimicrobial effectiveness was evaluated by the reduction of microbial counts. Lipopolissacharide complex presence was assessed by limulus amebocyte lysate test and B-lymphocyte stimulation. Data were analyzed by Wilcoxon and Mann-Whitney tests (5%). Ozonated water significantly reduced the number of C. albicans and E. faecalis at the immediate sampling, but increased values were detected after 7 days. Ozonated water did not neutralize endotoxin. It could be concluded that ozonated water was effective against C. albicans and E. faecalis but showed no residual effect. No activity on endotoxin was observed.     

Dentin enhances the effectiveness of bioactive glass S53P4 against a strain of Enterococcus faecalis.

OBJECTIVE: The aim of the current study was to test the impact of dentin powder on the antimicrobial efficacy of bioactive glass S53P4 (BAG). STUDY DESIGN: BAG was suspended (preincubated) in saline at 37 degrees C for different time periods with or without human dentin powder, hydroxylapatite, or decalcified dentin. Subsequently, Enterococcus faecalis ATCC 29212 cells were added to these suspensions and bacterial recovery measured with and without the use of gentle sonication. Furthermore, survival of bacteria in test and control suspensions was assessed over time. Supernatants of suspensions were analyzed for their element contents using atomic absorption spectrophotometry. The effects of pH, silica, and osmolarity on E faecalis viability were assessed using specifically prepared solutions. RESULTS: BAG preincubated with dentin powder caused a significant (P < .05) decrease in viability compared to pure BAG suspensions. This was not based on adherence of bacteria to solid particles or agglutination of the cells, because sonication did not increase bacterial yields. Hydroxylapatite and decalcified dentin did not increase BAG killing efficacy. The additive effect of BAG + dentin powder was dose dependent, occurred only with solids in suspension, and increased with suspension time. An augmented dissolution of glass components, especially silicon, was measured in BAG + dentin powder compared to pure BAG suspensions or counterparts containing hydroxylapatite or decalcified dentin. High osmolarity per se did not affect E faecalis viability, whereas high pH and silica levels did. CONCLUSION: The observed phenomenon was related to an increased BAG dissolution triggered by dentin powder, causing elevated local pH and silica levels.     

Antimicrobial effect, in vitro, of gutta-percha points containing root canal medications against yeasts and Enterococcus faecalis.

OBJECTIVE: The objective of this study was to determine the in vitro susceptibility of Enterococcus faecalis and the most prevalent Candida species as therapy-resistant microorganisms to gutta-percha points containing root canal medications. STUDY DESIGN: Gutta-percha points containing calcium hydroxide (Calcium Hydroxide Plus Points), chlorhexidine diacetate (Activ Points), or calcium hydroxide-chlorhexidine combinations (CHX/Ca Combi Points) were tested for their ability to inhibit growth of pure cultures of Candida albicans, Candida glabrata, Candida parapsilosis, Candida krusei, Candida tropicalis, Saccharomyces cerevisiae, and Enterococcus faecalis. Approximately 2 x 10(7) microorganisms per assay were suspended in diluted human serum and co-incubated with the gutta-percha points placed in Eppendorf tubes in an incubator for up to 2 weeks. A tube was removed at 1, 2, 3, 4, 7, and 14 days, and then opened and microorganism suspensions were serially diluted in a sterile 0.9% NaCl solution. Aliquots of the dilution steps were streaked onto solid medium. After incubating the plates in an incubator at 37 +/- 1 degrees C for 48 hours, CFU numbers per milliliter of suspension were calculated. RESULTS: Calcium Hydroxide Plus Points or Activ Points did not exhibit sufficient antimicrobial or anticandidal activity for Enterococcus faecalis, Candida albicans, C. glabrata, C. parapsilosis, C. krusei, or C. tropicalis within 14 days. Only Saccharomyces cerevisiae was susceptible to the calcium hydroxide or chlorhexidine diacetate containing gutta percha points. CHX/Ca Combi Points killed C. albicans, C. glabrata, C. krusei, C. tropicalis, and S. cerevisiae completely. However, E. faecalis and C. parapsilosis were resistant to CHX/Ca Combi points within 14 days. CONCLUSION: The results show the gutta percha points containing a mixture of calcium hydroxide and chlorhexidine diacetate have efficacies superior to calcium hydroxide or chlorhexidine diacetate alone against some microorganisms except E. faecalis and C. parapsilosis.     

The effect of calcium chelating or binding agents on Candida albicans.

OBJECTIVE: The aim of this study was to evaluate antifungal effects of calcium-chelating or -binding agents on Candida albicans comparing with conventional antifungal agents. STUDY DESIGN: Two clinical oral isolates and 1 standard strain of C albicans were included in the study. Test solutions were ethylenediamine-tetraacetic acid (EDTA), ethyleneglycol-tetraacetic acid (EGTA), sodium fluoride (NaF), titanium tetrafluoride (TiF4), nystatin, and ketoconazole. Minimum inhibitory and fungicidal concentrations of the solutions were determined. The results were analyzed statistically using Friedman's nonparametric 2-way ANOVA and Mann-Whitney U tests. RESULTS: All isolates demonstrated similar susceptibility patterns (P>.05). Except ketoconazole, EDTA had the highest antifungal and fungicidal activity, followed by TiF4. EGTA and NaF were the weakest agents against C albicans among all test solutions. CONCLUSION: EDTA and TiF4 may be recommended as an alternative irrigating solution particularly in persistent root canal infections and in root canals of patients having a high incidence of oral candidosis.     

In vitro assessment of an antibacterial quaternary ammonium-based polymer loaded with chlorhexidine for the coating of polypropylene prosthetic meshes

Purpose

This study assesses the use of an absorbable polymer loaded with chlorhexidine (CHX) as an antibacterial coating for polypropylene (PP) meshes employed in hernia repair.

Methods

The polymer N,N-dimethyl-N-benzyl-N-(2-methacryloyloxyethyl) ammonium bromide was loaded with CHX (1 % w/w). Fragments (1 cm²) of Optilene^® Mesh Elastic were coated either with the unloaded (POL) or CHX-loaded polymer (POL–CHX). Uncoated fragments (PP) served as controls. The release kinetics of the POL–CHX coating was monitored by HPLC. Sterile fragments were placed on agar plates previously contaminated with 10⁶ CFU of Staphylococcus aureus (Sa) ATCC25923, Staphylococcus epidermidis (Se) ATCC12228, or Escherichia coli (Ec) ATCC25922 and incubated at 37 °C for 1/2/7 days. At each time point, inhibition halos were measured and bacterial adhesion to the meshes quantified by sonication and scanning electron microscopy. Coating cytotoxic effects were examined on cultured fibroblasts.

Results

The polymer coating gradually released CHX over 3 days. Inhibition halos were produced only around the POL–CHX-coated meshes and these were significantly smaller for Ec than Sa or Se (p < 0.01). While POL–CHX prevented bacterial adhesion to the mesh, the reduced bacterial yields over time were observed for the POL-coated versus control PP meshes (p < 0.001). By day 7, only Ec remained attached to the surface of control meshes. The POL coating was not cytotoxic, yet POL–CHX reduced the viability of cultured fibroblasts.

Conclusions

When loaded with the antiseptic CHX, this quaternary ammonium-based polymer coating released its contents in a controlled manner indicating its potential prophylactic use to reduce the risk of infection following PP mesh implantation.

     

Duration-dependent susceptibility of endodontic pathogens to calcium hydroxide and chlorhexidene gel used as intracanal medicament: an in vitro evaluation.

The aim of this study was to evaluate the effective duration of antimicrobial activity of a calcium hydroxide-based medicament (Apex Cal) and 2% chlorhexidene gluconate gel against selected endodontic pathogens (Enterococcus faecalis, Candida albicans, Porphyromonas gingivalis, and Prevotella intermedia). The agar diffusion test was used to determine the antimicrobial activity. Chlorhexidene gluconate gel showed the largest inhibitory zones. The antimicrobial action of both medicaments decreased significantly with time, with calcium hydroxide showing no antimicrobial action after 72 hours. In conclusion, 2% chlorhexidene gel showed better antimicrobial activity than calcium hydroxide, and the effective antimicrobial action of both medicaments decreased after 48 hours.     

Effectiveness of a calcium hydroxide and chlorhexidine digluconate mixture as disinfectant during retreatment of failed endodontic cases.

OBJECTIVE: The purpose of this in vivo investigation is to compare the effect of a slurry of Ca(OH)2 mixed in aqueous 2% chlorhexidine (CHX) versus aqueous Ca(OH)2 slurry alone on the disinfection of the pulp space of failed root-filled teeth during endodontic retreatment. STUDY DESIGN: Forty single-rooted previously root-filled teeth with associated periradicular lesions were included. The teeth were nonsurgically retreated and medicated over 3 treatment visits with 7-10-day intervals with either Ca(OH)2 in water or Ca(OH)2 in 2% aqueous CHX. Root canal cultures were collected in fluid thioglycollate, and bacterial growth was assessed by turbidity daily for 1 week, then weekly for an additional 3 weeks. The presence of enterococci in the root canals at the initial treatment session was determined. RESULTS: Of the total sample population, 12 of 40 (30%) were positive for bacteria before root filling. The control medication disinfected 12 of 20 (60%) teeth including 2 of 4 teeth originally diagnosed with enterococci. The experimental medication resulted in disinfected 16 of 20 (80%) teeth at the beginning of the third appointment. None of the teeth originally containing enterococci showed remaining growth. This difference between the overall positive cultures was not statistically significant (P > .05). CONCLUSIONS: Canal dressing with a mixture of 2% CHX and Ca(OH)2 slurry is as efficacious as aqueous Ca(OH)2 on the disinfection of failed root-filled teeth.     

Effectiveness of antimicrobial photodynamic therapy with indocyanine green against the standard and fluconazole-resistant Candida albicans

Lasers in Medical Science - Antimicrobial photodynamic therapy (aPDT) is an alternative approach. The current study aimed to investigate the efficacy of aPDT with indocyanine green (ICG) against...     

甲硝唑碘仿氢氧化钙糊剂与维他派克斯糊剂在根尖周炎治疗及根管诱导成形术中的疗效

目的对甲硝唑碘仿氢氧化钙糊剂和维他派克斯（VITAPEX）糊剂在根尖周炎治疗与根管诱导成形术中的治疗效果进行分析。方法选取2007年1月至2012年1月在本院就诊的80例患者发生牙髓坏死的94例年轻恒牙作为研究对象,随机分为观察组和对照组,分别给予甲硝唑碘仿氢氧化钙糊剂和VITAPEX糊剂,治疗后对患者的身体状况进行6个月、1年和2年的随访,并对患者的成功率以及根管成形术中的疼痛发生率进行对比分析。结果与对照组相比,观察组患者术后第3天疼痛消失率显著增高（χ2=4.401,P＜0.05）;观察组患者术后6个月,术后1年和术后2年根据疗效判定的成功率较对照组显著升高（P均＜0.05）。结论甲硝唑碘仿氢氧化钙糊剂既能有效地治疗根尖周炎,又能减轻由根管诱导成形术所带来的疼痛,值得在临床工作中推广使用。     

In vitro bacteriological evaluation of the effectiveness of antimicrobial irrigating solutions.

Nineteen strains of pathogenic aerobic bacteria were exposed for fifteen seconds in vitro to varying concentrations of five antibiotics and of polyvinyl povidone iodine in saline solution. The presence of human plasma in the solution (30 per cent by volume) did not affect bacterial sensitivity to the antibiotics. Most of the bacteria were sensitive to the solutions during that brief exposure. Bacteria which were more sensitive by disc sensitivity tests were more sensitive to the solutions. Polyvinyl povidone iodine sterilized all cultures in concentrations as low as 25 per cent. It is proposed that the use of appropriate antimicrobial solutions as wound irrigants may reduce postoperative infection rates by killing bacteria which contaminate the surface of the wound during operation.     

Pre-inoculation of urinary catheters with Escherichia coli 83972 inhibits catheter colonization by Enterococcus faecalis.

PURPOSE: The capacity of a preexisting coating of Escherichia coli 83972 to reduce catheter colonization by Enterococcus faecalis 210 was investigated. Enterococcus was chosen for these trials since it is a common urinary pathogen in patients with an indwelling urinary catheter. MATERIALS AND METHODS: Each experiment tested 3 growth conditions. Group 1 or E. coli plus Enterococcus catheters were exposed to E. coli 83972 for 24 hours and then to Enterococcus for 30 minutes. Group 2 or E. coli alone catheters were incubated in E. coli for 24 hours and then in sterile broth for 30 minutes. Group 3 or Enterococcus alone catheters did not undergo the initial incubation with E. coli before the 30-minute incubation with Enterococcus: All catheters were then incubated in sterile human urine for 24 hours. Catheters were washed with saline and cut into 5, 1 cm. segments. Each segment was sonicated and the sonication fluid was diluted and plated. The results of each of the 5 segments were averaged and the set of experiments was repeated 7 times. RESULTS: A preexisting coating of E. coli 83972 reduced catheter colonization by E. faecalis 210 more than 10-fold. Enterococcus alone catheters had a median of 9.7 x 10(5) enterococci per cm., whereas E. coli plus Enterococcus catheters had a median of 0.38 x 10(5) enterococci per cm. (p = 0.016). CONCLUSIONS: Pre-inoculating urinary catheters with E. coli 83972 significantly impedes catheter colonization by Enterococcus: These promising in vitro results prompt the clinical investigation of this particular application of bacterial interference.     

Candida albicans and filtrates interfere with human spermatozoal motility and alter the ultrastructure of spermatozoa: an in vitro study

The in vitro effects of Candida albicans and its filtrates on the motility and ultrastructure of human spermatozoa from healthy donors were studied. A significant reduction in sperm progressive motility and signs of membrane alteration, directly related to contact time were observed. Distinct adhesion of spermatozoa to C. albicans and agglutination were observed. Light and transmission electron microscopy examinations showed that spermatozoa attached to C. albicans mainly via the head. Multiple ultrastructural lesions were present, which were the possible morphological reasons for spermatozoan immobilization observed in the present study. It is concluded that C. albicans as well as its filtrates had an inhibitory effect on human sperm motility and impaired the ultrastructure of human spermatozoa, which could be associated with male infertility.