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1.
This study compared the antibacterial effect of 2% clindamycin and 2% and 100% concentration of triple antibiotic paste (TAP) on an Enterococcus faecalis biofilm. Dentinal tubules of 100 root specimens were infected and randomly assigned to five groups. A total of 1000 mg mL?1 of TAP, 20 mg mL?1 of TAP and clindamycin, calcium hydroxide or methylcellulose (control) were placed in the root canal for 1 week. After treatment, dentine shavings were collected from 200 and 400 μm dentine depth and the number of colony‐forming units (CFU) per mg was determined. Reduction in viable bacteria in first three groups was significantly better than calcium hydroxide and control groups. However, the antimicrobial effectiveness among these three groups was not significantly different from each other. There was no significant difference between data at 200 and 400 μm in all groups except the Ca(OH)2 group. The antibiofilm effect of clindamycin was comparable with TAP, so it may be used instead of TAP.  相似文献   

2.
Several studies have questioned the antimicrobial role of calcium hydroxide cements. This study assessed the antimicrobial activity of four commercially available calcium hydroxide cements on Streptococcus sanguis NCTC 7864 using inoculated Mueller-Hinton growth medium. Growth curves from optical density analysis, pH measurements, and viability counts were compared over a 24 h period. Significant differences occurred (P > 0.05) between pH measurements but not the growth curves or the viability counts. All cements exerted a cidal effect although this cannot be attributed to an increase in alkalinity alone.  相似文献   

3.
The antimicrobial effects of aqueous preparations of calcium hydroxide have been demonstrated in the past. Calcium hydroxide, when dissolved in water, dissociates into hydroxide and calcium ions. The presence of hydroxide ions in a solution makes it antimicrobial. Recently it was shown that the use of glycerin as a mixing vehicle facilitates placement of calcium hydroxide in the root canals. The influence of nonaqueous mixing vehicles on the dissociation of calcium hydroxide is not clearly understood. In this study the conductivity of aqueous and nonaqueous solutions of calcium hydroxide was measured. The conductivity values for saturated solutions of calcium hydroxide in water was 7.3+/-3 mS/cm. The conductivity of calcium hydroxide in pure glycerin or propylene glycol was essentially zero. It was concluded that use of nonaqueous mixing vehicles may impede the effectiveness of calcium hydroxide as a root canal dressing.  相似文献   

4.
The antimicrobial activity of substances used as antibacterial agents (solutions of 10% calcium hydroxide, camphorated paramonochlorophenol - PMCC, 2% chlorhexidine digluconate and 10% castor oil plant detergent) on anaerobic bacteria (Fusobacterium nucleatum ATCC 25586, Prevotella nigrescens ATCC 33563, Clostridium perfringens ATCC 13124 and Bacteroidesfragilis ATCC 25285), using a broth dilution technique, was evaluated in vitro. For determination of minimum inhibitory and minimum bactericide concentrations (MIC and MBC), two culture broths, Reinforced Clostridial Medium (RCM) and supplemented Brucella, standardized inoculum and serially diluted solutions were used. All antibacterial agents presented antimicrobial activity that varied for different bacteria. There were no differences in the performance of the two broths. Chlorhexidine digluconate was the most effective, with the lowest MICs, followed by castor oil detergent, PMCC and calcium hydroxide. C. perfringens and B. fragilis were the most resistant bacteria to all agents.  相似文献   

5.
The effects of different growth conditions on the susceptibility of five taxa to alkaline stress were investigated. Enterococcus faecalis ATCC 29212, Streptococcus sobrinus OMZ 176, Candida albicans ATCC 90028, Actinomyces naeslundii ATCC 12104, and Fusobacterium nucleatum ATCC 10953 were grown as planktonic cells, allowed to adhere to dentin for 24 hours, grown as monospecies or multispecies biofilms on dentin under anaerobic conditions with a serum-enriched nutrient supply at 37 degrees C for 5 days. In addition, suspended biofilm microorganisms and 5-day old planktonic multispecies cultures were used. Microbial recovery upon direct exposure to saturated calcium hydroxide solution (pH 12.5) for 10 and 100 minutes was compared with control exposure to physiologic saline. Planktonic microorganisms were most susceptible; only E. faecalis and C. albicans survived in saturated solution for 10 minutes, the latter also for 100 minutes. Dentin adhesion was the major factor in improving the resistance of E. faecalis and A. naeslundii to calcium hydroxide, whereas the multispecies context in a biofilm was the major factor in promoting resistance of S. sobrinus to the disinfectant. In contrast, the C. albicans response to calcium hydroxide was not influenced by the growth condition. Adherence to dentin and interspecies interactions in a biofilm appear to differentially affect the sensitivity of microbial species to calcium hydroxide.  相似文献   

6.
The purpose of this investigation was to examine the in vitro susceptibility of Candida albicans to a mixture of chlorhexidine and calcium hydroxide using a tube dilution test. A suspension containing C. albicans was exposed to 2% chlorhexidine solution, calcium hydroxide paste and 2% chlorhexidine mixed with calcium hydroxide in plastic tissue culture wells. The tested agents were incubated with C. albicans for 1, 24, or 72 h. All agents were effective anti‐fungals at all experimental time periods tested, with the exception of exposure to calcium hydroxide for 1 h. A mixture of 2% chlorhexidine and calcium hydroxide therefore is a very effective anti‐fungal agent against C. albicans.  相似文献   

7.
Control of microorganisms in vitro by endodontic irrigants   总被引:1,自引:0,他引:1  
The aim of this study was to determine the minimum inhibitory concentration (MIC) and antimicrobial effectiveness by the direct exposure test of 4 endodontic irrigants [1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 1% calcium hydroxide (Ca(OH)2; prepared with 1 g of Ca(OH)2 and 100 mL of sterile distilled water), a solution of Ca(OH)2 + detergent (HCT20)] for S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans and a mixed culture. Microbial growth was analyzed by two methods: turbidity of the culture medium that was confirmed by Gram stain and subculture in a specific nutrient broth. In the dilution test, NaOCl solution showed MIC equal to 0.1% for S. aureus, E. faecalis, P. aeruginosa and C. albicans and equal to 1% for B. subtilis and the mixed culture. CHX (2%) presented MIC equal to 0.000002% for S. aureus, 0.02% for E. faecalis, B. subtilis, C. albicans and the mixed culture and 0.002% for P. aeruginosa. Ca(OH)2 solution (1%) showed MIC greater than 1% for all the microorganisms except P. aeruginosa for which it was equal to 1%. Calcium hydroxide solution + detergent showed MIC equal to 4.5 mL for S. aureus, P. aeruginosa, B. subtilis, C. albicans and the mixed culture and greater than 4.5 mL for E. faecalis. In the direct exposure test, NaOCl had better antimicrobial effectiveness for all microorganisms at all times. CHX (2%) was effective for S. aureus, E. faecalis and C. albicans at all times, and ineffective for P. aeruginosa, B. subtilis and the mixed culture. The other solutions showed the worst results.  相似文献   

8.
Aim: To assess the effectiveness of mineral trioxide aggregate (MTA) used as an indirect pulp‐capping material in human molar and premolar teeth. Methodology: We conducted a clinical evaluation of 60 teeth, which underwent an indirect pulp‐capping procedure with either MTA or calcium hydroxide cement (Dycal®). Calcium hydroxide was compared with MTA and the thickness of the newly formed dentine was measured at regular time intervals. The follow‐up was at 3 and 6 months, and dentine formation was monitored by radiological measurements on digitised images using Mesurim Pro® software. Results: At 3 months, the clinical success rates of MTA and calcium hydroxide were 93% and 73%, respectively (P = 0.02). At 6 months, the success rate was 89.6% with MTA, and remained steady at 73% with calcium hydroxide (P = 0.63). The mean initial residual dentine thickness was 0.23 mm, and increased by 0.121 mm with MTA and by 0.136 mm with calcium hydroxide at 3 months. At 6 months, there was an increase of 0.235 mm with MTA and of 0.221 mm with calcium hydroxide. Conclusions: A higher success rate was observed in the MTA group relative to the Dycal® group after 3 months, which was statistically significant. After 6 months, no statistically significant difference was found in the dentine thickness between the two groups. Additional histological investigations are needed to support these findings.  相似文献   

9.
AIM: To evaluate the effect of biomechanical preparation with different irrigating solutions and calcium hydroxide dressing in dog root canals containing bacterial endotoxin (lipopolysaccharides; LPS). METHODOLOGY: One hundred and forty premolar roots from seven dogs were filled with Escherichia coli LPS for 10 days (three roots were lost during histological processing). The following irrigating solutions were used for biomechanical preparation: 1% (group I, n = 20), 2.5% (group II, n = 19) and 5% sodium hypochlorite (group III, n = 19), 2% chlorhexidine digluconate (group IV, n = 20) and physiological saline solution (group V, n = 19). In group VI (n = 20), the LPS solution was maintained in the root canal during the entire experiment and in group VII (n = 20), after biomechanical preparation with saline solution, the root canals were filled with a calcium hydroxide dressing (Calen; control). After 60 days, the animals were sacrificed and the following parameters of periapical disease were evaluated: (a) inflammatory infiltrate, (b) periodontal ligament thickness, (c) cementum resorption and (d) bone resorption. Scores were given and data were analysed statistically with the Kruskal-Wallis and Dunn tests (P < 0.05). RESULTS: Histopathological evaluation showed that groups I-VI had more inflammatory infiltrate, greater periodontal ligament thickening and greater cementum and bone resorption (P < 0.05) compared to group VII, which received the calcium hydroxide intracanal dressing. CONCLUSIONS: Biomechanical preparation with the irrigating solutions did not inactivate the effects of the endotoxin but the calcium hydroxide intracanal dressing did appear to inactivate the effects induced by the endotoxin in vivo.  相似文献   

10.
Abstract A total of 44 roots with periradicular inflammation, induced by inoculation of Streptococcus faecalis, were treated endodontically. All root canals were prepared with K-reamers using 0.5% solution of sodium hypochlorite for irrigation. Bacteriological specimens demonstrated growth in all teeth when the root-canal fillings were made. In all, 22 roots were filled with gutta-percha, 11 roots with a calcium hydroxide preparation (Cala-sept®) and 11 roots with Calasept®+ Dionosil®, an iodinized radio-graphic contrast medium. The addition of Dionosil® improved the possibility of evaluating the placement of the calcium hydroxide paste. Dressings with calcium hydroxide are recommended in the treatment of teeth with apical periodontitis.  相似文献   

11.
Abstract The current investigation was initiated to study the effect concentration and application time has on the rate of tetracycline demineralization of dentin. Buccal and lingual surfaces of extracted bovine molars were ground to a smooth flat dentin surface using wetted silicon carbide discs. Standardized depressions were made in the dentin surface with a #909-055 diamond round wheel. Fresh tetracycline HCl (TTC-HCl) (Flavine Int. Inc.) solutions, i.e., 0, 25, 50, 75, 100, 125 and 150 mg/ml were prepared. A 30% citric acid solution was used as a positive control. The pH of each solution was recorded. 7 μl of each solution were pipetted into a depression and remained undisturbed for 1, 3, or 5 min. At the end of each application time period a fresh #3 cotton pellet was placed in the depression, once every 20 s for 1 min, to soak up the solution. The 3 pellets were placed in a 2.00 ml of 18 Mω H2O sample. As a measure of the rate of demineralization the parts per million calcium (ppm Ca++) found in each sample were determined using atomic absorption spectrophotometry. Two-way analysis of variance was used to determine effects of TTC-HC1 concentration and time on the rate of demineralization. No significant differences were found in the mean ppm Ca++ released at 1-, 3- and 5-min application times for 0, 25, or 50 mg/ml TTC. No significant differences were found in the mean ppm Ca++ released (i) between 3- and 5-rmn application times for 75, 100, 125 and 150 mg/ml TTC-HCl solutions and (ii) between 75, 100, 125 and 150 mg/ml TTC-HCl solutions within either the 3- or 5-min application times. The mean ppm Ca++ released at 3- and 5-min application times for 75, 100, 125 and 150 mg/ml TTC-HCl solutions were all significantly greater than the respective readings at the 1-min application time. The mean ppm Ca++ recorded for the 30% citric acid solution for all 3 application times were 3 to 5.5 × greater than the highest mean ppm Ca++ recording for TTC-HCl. The results of this study show that a 3-min application time of 75 mg/ml TTC-HCl solution is equally as effective at demineralizing dentin as is higher concentrations and/or longer application times, but was far less effective than a 30% citric acid solution.  相似文献   

12.
Introduction The species Enterococcus faecalis has been recovered in a high proportion of endodontic failures – approximately one‐third of failed cases with recoverable bacteria contain monoinfections of the microorganism. Eradication of E. faecalis from an infected root canal is difficult, which means that it is a significant clinical problem in endodontic treatment. E. faecalis is known to be resistant to the alkaline bactericidal effect of calcium hydroxide, yet the survival mechanisms of E. faecalis that enable it to tolerate exposure to the high pH of calcium hydroxide are poorly understood. Because endodontic treatment involves repeated or alternate use of antimicrobial agents at various stages, these conditions could adapt or ‘pre‐treat’ cells by eliciting a stress response that enhances their survival. An ability to mount a stress response involving synthesis of general or specific stress‐induced proteins is an important survival mechanism for many bacteria. The production of these stress‐induced proteins protects cells from adverse conditions, facilitating cell recovery when more favourable conditions are re‐established. This study sought to clarify the mechanisms that enable E. faecalis to survive the high pH of calcium hydroxide. Methods E. faecalis strain JH2–2. was exposed to sub‐lethal concentrations of calcium hydroxide, with and without various pre‐treatments. Blocking agents were added to determine the role of stress‐induced protein synthesis and the cell wall‐associated proton pump. Results E. faecalis was resistant to calcium hydroxide at a pH of 11.1, but not pH 11.5. Pre‐treatment with calcium hydroxide pH 10.3 induced no tolerance to further exposure at pH 11.5. No difference in cell survival was observed when protein synthesis was blocked by Chloramphenicol during stress induction. However, addition of the proton pump inhibitor, CCCP, resulted in a dramatic reduction of cell viability of E. faecalis in calcium hydroxide. Conclusions This study confirmed that E. faecalis is resistant to killing by calcium hydroxide. An adaptive response in alkaline pH and stress‐induced protein synthesis do not play a role in cell survival. However, a functioning proton pump with the capacity to drive protons into the cell and acidify the cytoplasm is critical for survival of E. faecalis at high pH. These findings contribute to our understanding of the response by E. faecalis to the antimicrobial action of calcium hydroxide and may open the possibility of novel approaches to address this clinical problem in endodontic treatment.  相似文献   

13.
Abstract The tissue solvent capacity of a 2% stabilized sodium hypochlorite solution (Milton®) and a commercial calcium hydroxide solution (Calasept®) was examined under in vitro conditions where autolyzed human pulp fragments weighing approximately 0.0065 g were immersed in these solutions at 37°C for periods of up to 10 days. It appeared that sodium hypochlorite was able to dissolve half the volume of pulp tissue within 1 h and the remaining tissue after 2–2 1/2 h. Calcium hydroxide dissolved half the pulp volume within 2 h, whereas it took 1 week for the remaining tissue to dissolve. These findings support the use of sodium hypochlorite as an irrigation solution during canal preparation and calcium hydroxide as a canal dressing for the purpose of creating a canal free of pulp remnants before root filling.  相似文献   

14.
Cyclic voltammetry is used to deposit films of hydrous iridium oxide onto glassy carbon electrodes from a basic solution of saturated iridium(III) oxide. An acidic solution of Ir(OH2)2Cl4? is first prepared from either IrCl63 or IrCl62?. When this solution is made basic, iridium (IV) oxide is deposited by oxygen generated from oxidation of hydroxide. A strongly adherent, bright blue deposit of iridium oxide is formed after 10 to 20 scans between ?0.3 and +1.0 V vs. Ag|AgCl. The modified electrodes exhibit a super-Nernstian response to pH similar to that observed for iridium oxide grown electrochemically on iridium substrates. The ph response is reproducible and remains stable over a period of several days.  相似文献   

15.
The aim of this study was to investigate the antimicrobial activity of propolis‐based intracanal medicament against Enterococcus faecalis using infected dentine models, and to compare its antimicrobial efficacy with that of the non‐setting calcium hydroxide paste when used as a short‐term medication for 1 and 2 days. A total of 50 dentine discs of 7‐mm length was obtained from extracted human teeth. Five dentine discs were kept sterile to serve as a negative control. The remaining 45 were contaminated with E. faecalis and divided into two groups (n = 20) in addition to five discs that served as a positive control. The discs were treated as follow: 20 discs were filled with propolis, while the other 20 discs were filled with non‐setting calcium hydroxide. Microbiological sampling was performed utilising sterile paper point, headstrom file and disc immersion. Results showed that propolis was significantly more effective than non‐setting calcium hydroxide against E. faecalis after short‐term application, which made comparison from this prospect unlevelled. The most effective microbiological sampling technique was abrading the lumen with headstrom file. Propolis is very effective as intracanal medicament in rapidly eliminating E. faecalis ex vivo.  相似文献   

16.

Introduction

The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions.

Methods

The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083).

Results

Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P < .0083). There were no significant differences among the other groups (P > .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups.

Conclusions

Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid.  相似文献   

17.
Oral streptococci are present in large numbers in dental plaque and several types interact with the enamel salivary pellicle to form a biofilm on tooth surfaces. The respective affinity of individual streptococci for salivary components has an influence on the etiologic properties of oral biofilm in the development of dental caries. We studied real‐time biospecific interactions between oral streptococci and salivary components utilizing biosensor technology to analyze surface plasmon resonance. Streptococcus sanguis and Streptococcus mutans showed significant responses for binding to salivary components, in comparison with other bacteria. Further, the association rates (4.1 × 10?11/bacterium) and dissociation rate (5.7 ± 0.9 × 10?3 Second(s)?1) were higher for S. sanguis than for S. mutans (2.4 × 10?11 and 2.9 ± 0.8 × 10?3) and Streptococcus mitis (1.3 × 10?11 and 3.5 ± 1.3 × 10?3). However, the association equilibrium constants (8.2 S/bacterium) for S. mutans was 2 times higher in than S. mitis (3.8) and slightly higher than S. sanguis (7.2). These findings may provide useful information regarding the mechanism of early biofilm formation by streptococci on the tooth surface.  相似文献   

18.
This study examined the effects of direct pulp capping treatment using super-pulsed CO2 laser preirradiation on the wound healing process of exposed rat pulp on days 1, 3, 7, 14, and 28 postoperatively. Group 1 was irradiated with a CO2 laser and directly capped with a self-etching adhesive system. The laser was operated in super-pulse mode (pulse duration, 200 μs; interval, 5800 μs; 0.003 J/pulse). The irradiation conditions were a power output of 0.5 W, an irradiation time of 3 s, and repeat mode (10 ms of irradiation at 10-ms intervals for a total beam exposure time of 1.5 s), defocused beam diameter of 0.74 mm (approximately 20 mm from the exposed pulp surface), energy density of 0.698 J/cm2 per pulse, total applied energy of 0.75 J, and an activated air-cooling system. Group 2 was capped with the self-etching adhesive system. Group 3 was capped with commercially available calcium hydroxide, and the self-etching adhesive system was applied to the cavity. The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation, and bacterial penetration. The results were statistically analyzed using the Kruskal-Wallis test for differences among the groups at each observation period (P < 0.05). There were no significant differences among the experimental groups in any parameters at any postoperative period (P > 0.05). CO2 laser irradiation was effective in arresting hemorrhaging but showed a tendency to delay reparative dentin formation compared with the application of calcium hydroxide.  相似文献   

19.

Objectives

The purpose of this study was to evaluate the application of 15 % propolis and 2 % acidulated-phosphate sodium fluoride solutions on the root surface-adhered necrotic cemental periodontal ligament in delayed tooth replantation.

Materials and methods

Thirty Wistar rats (Rattus norvegicus, albinus) had their right upper incisor extracted and maintained in dry storage for 60 min. After this period, the dental papilla, enamel organ, and pulp tissue were removed, and the animals were randomly assigned to three groups: group I = immersion in saline for 10 min; group II = immersion in a 2 % acidulated-phosphate sodium fluoride solution for 10 min; and group III = immersion in a 15 % propolis and propylene glycol solution for 10 min. The root canals were filled with a calcium hydroxide paste and the teeth were replanted.

Results

Inflammatory resorption, replacement resorption, and ankylosis were observed in all groups without a statistically significant difference (p?>?0.05) among them.

Conclusions

Under the tested conditions, the application of fluoride or propolis on root surface-adhered necrotic periodontal ligament did not favor the healing process in delayed tooth replantation.  相似文献   

20.
The response of the dentin–pulp complex in rat teeth was investigated after direct capping with biodentine with or without bone marrow‐derived stem cells (BMDSCs). Following mechanical exposure, pulps were randomly capped with one of the followings materials: calcium hydroxide, biodentine or 1 × 105 BMDSCs mL?1 + biodentine. Histological examination was performed by light microscopy after 1, 3 and 5 weeks. Inflammatory reaction, necrotic tissue formation and calcific bridge formation were scored. Analysis showed that compared with the effects of calcium hydroxide or biodentine, BMDSCs + biodentine substantially reduced inflammatory reaction and necrotic tissue while promoting calcified tissue formation. Therefore, the combination of biodentine and BMDSCs could potentially stimulate pulp tissue regeneration after direct pulp capping.  相似文献   

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