RESUMO
The objective of this study was to analyze two methods for determining the antimicrobial effectiveness of (i) calcium hydroxide plus saline, (ii) calcium hydroxide plus polyethylene glycol, and (iii) calcium hydroxide plus camphorated paramonochlorophenol. Four microorganisms (Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853), and Bacillus subtilis (ATCC 6633)), one yeast (Candida albicans (ICB/USP-562)), and one mixture of these organisms were used. The strains were inoculated in Brain Heart Infusion (BHI) and incubated at 37 degrees C for 24 h. Two methods, the direct exposure test and the agar diffusion test were used to evaluate antimicrobial effects. For the direct exposure test (DET) 288 paper points were contaminated with the standard microbial suspensions and exposed to the intracanal dressings for 1, 24, 48, and 72 h. The points were immersed in Letheen Broth, followed by incubation at 37 degrees C for 48 h. An inoculum of 0.1 ml obtained from Letheen Broth was then transferred to 7 ml of BHI under identical incubation conditions, and microbial growth was evaluated. Pastes showed activity between 1 and 72 h, depending on the microorganism/mixture tested. For the agar diffusion test 36 Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the same microbial suspension used for the DET, using sterile swabs that were spread on the medium. Five cavities were made in each of two agar plates (total = 10) and completely filled with one of the calcium hydroxide pastes. The plates were preincubated for 1 h at environmental temperature and then incubated at 37 degrees C for 24 to 48 h. The inhibition zone around each well was recorded in millimeters, and the results were submitted to ANOVA and Tukey test (alpha = 0.05). All intracanal dressings induced inhibition zones (range 5.0-10.0 mm). Data obtained showed that both the DET and agar diffusion test are useful in establishing the calcium hydroxide antimicrobial spectrum, thus improving infection control protocols. The direct exposure method is independent of other variables and is a practical laboratory procedure. A complete antimicrobial effect was observed after 48 h on indicator microorganisms, in both tests, irrespective of the calcium hydroxide paste vehicle.
Assuntos
Hidróxido de Cálcio/farmacologia , Testes de Sensibilidade Microbiana/métodos , Irrigantes do Canal Radicular/farmacologia , Análise de Variância , Bacillus subtilis/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Veículos Farmacêuticos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Estatísticas não ParamétricasRESUMO
The objective of this study was to investigate the antimicrobial action of mineral trioxide aggregate (MTA), Portland cement, calcium hydroxide paste (CHP), Sealapex and Dycal. The chemical elements of MTA and two Portland cements were also analyzed. Four standard bacterial strains: Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), one wild fungus, Candida albicans (ICB/USP-562), and one mixture of these were used. Thirty Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the experimental suspensions. Three cavities, each one measuring 4 mm in depth and 4 mm in diameter, were made in each agar plate using a copper coil and then completely filled with the product to be tested. The plates were pre-incubated for 1 h at environmental temperature followed by incubation at 37 degrees C for 48 h. The diameters of the zones of microbial inhibition were then measured. Samples from diffusion and inhibition halos were extracted from each plate and immersed in 7 ml BHI broth and incubated at 37 degrees C for 48 h. Analyses of chemical elements present in MTA and in two samples of Portland cement were performed with a fluorescence spectrometer Rx. The results showed that the antimicrobial activity of CHP was superior to those of MTA, Portland cement, Sealapex and Dycal, for all microorganisms tested, presenting inhibition zones of 6-9.5 mm and diffusion zones of 10-18 mm. MTA, Portland cement, and Sealapex presented only diffusion zones and among these, Sealapex produced the largest zone. Dycal did not show inhibition or diffusion zones. Portland cements contain the same chemical elements as MTA except that MTA also contains bismuth.
Assuntos
Anti-Infecciosos/farmacologia , Cimentos Dentários/farmacologia , Materiais Restauradores do Canal Radicular/farmacologia , Compostos de Alumínio/análise , Compostos de Alumínio/química , Compostos de Alumínio/farmacologia , Antibacterianos , Bacillus subtilis/efeitos dos fármacos , Compostos de Cálcio/análise , Compostos de Cálcio/química , Compostos de Cálcio/farmacologia , Hidróxido de Cálcio/química , Hidróxido de Cálcio/farmacologia , Candida albicans/efeitos dos fármacos , Cimentos Dentários/análise , Cimentos Dentários/química , Capeamento da Polpa Dentária , Difusão , Combinação de Medicamentos , Enterococcus faecalis/efeitos dos fármacos , Humanos , Minerais/química , Minerais/farmacologia , Óxidos/análise , Óxidos/química , Óxidos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/química , Salicilatos/química , Salicilatos/farmacologia , Silicatos/análise , Silicatos/química , Silicatos/farmacologia , Espectrometria de Fluorescência , Staphylococcus aureus/efeitos dos fármacosRESUMO
The objective of this study was to evaluate the antimicrobial activity of calcium hydroxide in infected dentinal tubules. Four microorganisms, strains of ATCC (Streptococcus faecalis (ATCC-29212), Staphylococcus aureus (ATCC-6538), Bacillus subtilis (ATCC-6633), and Pseudomonas aeruginosa (ATCC-27853)) and one mixture of these were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37 degrees C for 24 h. Sixty-three human maxillary central incisors were prepared and sterilized by autoclaving. Five groups of 12 teeth each were contaminated for 28 days using new 24-h cultures every 72 h, prepared and adjusted to tube 2 of the MacFarland scale (6 x 10(8) cells/ml). Root canals were then irrigated with 5 ml of saline, dried, and completely filled with calcium hydroxide paste. At intervals of 0, 48, and 72 h, and 7 days, dressings were removed and teeth were immersed in 5 ml of BHI and incubated at 37 degrees C for 48 h to observe the growth and multiplication of the microorganisms. Three uninoculated teeth were maintained in a humid environment as an aseptic control. These teeth were immersed in BHI and maintained at 37 degrees C for 7 days to determine microbial growth. Bacterial growth was shown by turbidity of the culture medium and confirmed by seeding these broths on BHI agar at 37 degrees C for 24 h. The positive BHI tubes were selected, and inoculum was spread on the surface of BHI agar, followed by the same incubation conditions. Gram stain was conducted from BHI growth and from colonies growing on solid medium. Calcium hydroxide in infected dentinal tubules showed no antimicrobial effect on S. faecalis, S. aureus, B. subtilis, P. aeruginosa, or on the bacterial mixture used throughout the experiment.
Assuntos
Hidróxido de Cálcio/farmacologia , Dentina/microbiologia , Irrigantes do Canal Radicular/farmacologia , Bacillus subtilis/efeitos dos fármacos , Dentina/ultraestrutura , Enterococcus faecalis/efeitos dos fármacos , Humanos , Incisivo , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacosRESUMO
The current discussion about the importance of intracanal dressings and the effect of vehicles on calcium hydroxide pastes is justified by controversy concerning the achievement of complete disinfection after preparation of infected root canals and the real antimicrobial effect of these vehicles. The aim of this study is to investigate the role of vehicles in the antimicrobial effect of calcium hydroxide pastes. Well-conducted research about the characteristics of calcium hydroxide, such as antimicrobial potential, physico-chemical aspects and histocompatibility, gives credibility to the choice of this medication in several clinical situations. Different vehicles have been added to calcium hydroxide in an attempt to enhance its properties. Scientific reasoning indicates the use of hydrosoluble vehicles (distilled water, saline) associated with calcium hydroxide because of their chemical characteristics of dissociation, diffusibility and filling capability which are decisive for the biological behavior, i.e., antimicrobial qualities and induction of tissue repair.
Assuntos
Anti-Infecciosos Locais/administração & dosagem , Hidróxido de Cálcio/administração & dosagem , Irrigantes do Canal Radicular/administração & dosagem , Anti-Infecciosos Locais/química , Hidróxido de Cálcio/química , Concentração de Íons de Hidrogênio , Transporte de Íons , Testes de Sensibilidade Microbiana , Veículos Farmacêuticos/química , Veículos Farmacêuticos/farmacologia , Irrigantes do Canal Radicular/química , Solubilidade , ÁguaRESUMO
The objective of this study was to determine in vitro the time required for calcium hydroxide in direct contact with microorganisms to express its antimicrobial effect. The microorganisms used were: Micrococcus luteus (ATCC-9341), Staphylococcus aureus (ATCC-6538), Fusobacterium nucleatum (ATCC-25586), Pseudomonas aeruginosa (ATCC-27853), Escherichia coli, and Streptococcus sp. The strains were cultivated in Brain Heart Infusion (BHI), with the exception of F. nucleatum (BHI-PRAS). Pure and mixed suspensions of the microorganisms were prepared. Paper cones immersed in these substances were covered with calcium hydroxide paste, and after 0, 1, 2, 6, 12, 24, 48, and 72 h and 7 days they were transferred to an appropriate medium to observe the growth and multiplication of the microorganisms. Incubation was conducted at 37 degrees C for 48 h, according to the requirements of oxygen of each microorganism. The antimicrobial effect of calcium hydroxide was shown to occur after 12 h on M. luteus and F. nucleatum, 24 h on Streptococcus sp, 48 h on E. coli, and 72 h on S. aureus and P. aeruginosa. Mixture II (M. luteus + Streptococcus sp + S. aureus) was sensitive to calcium hydroxide antimicrobial potential after 48 h, whereas mixture I (M. luteus + E. coli + P. aeruginosa), mixture III (E. coli + P. aeruginosa), and mixture IV (S. aureus + P. aeruginosa) were inactivated after 72 h of exposure.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Hidróxido de Cálcio/farmacologia , Irrigantes do Canal Radicular/farmacologia , Testes de Sensibilidade Microbiana/estatística & dados numéricos , Fatores de TempoRESUMO
The biological and bacteriological action of calcium hydroxide confer to its current success as an intracanal dressing. For this reason the mechanism of action of calcium and hydroxyl ions on tissue and bacteria deserves further study. The objective of the present paper is to analyze and discuss the mechanism of action of calcium and hydroxyl ions on anaerobic bacteria, starting from the isolated study of the influence of pH on these bacteria , as well as the mechanism of action of calcium hydroxide on tissue.