RESUMEN
BACKGROUND: A new intercellular communication mode established by neoplastic cells and tumor microenvironment components is based on extracellular vesicles (EVs). However, the biological effects of the EVs released by tumor cells on angiogenesis are not completely understood. Here, we aimed to understand the biological effects of EVs isolated from two cell lines of oral squamous cell carcinoma (OSCC) (SCC15 and HSC3) on endothelial cell tubulogenesis. METHODS: OSCC-derived EVs were isolated with a polymer-based precipitation method, quantified using nanoparticle tracking analysis and verified for EV markers by dot blot. Functional assays were performed to assess the angiogenic potential of the OSCC-derived EVs. RESULTS: The results showed that EVs derived from both cell lines displayed typical spherical-shaped morphology and expressed the EV markers CD63 and Annexin II. Although the average particle concentration and size were quite similar, SCC15-derived EVs promoted a pronounced tubular formation associated with significant migration and apoptosis rates of the endothelial cells, whereas EVs derived from HSC3 cells inhibited significantly endothelial cell tubulogenesis and proliferation. CONCLUSION: The findings of this study reveal that EVs derived from different OSCC cell lines by a polymer-based precipitation method promote pro- or anti-angiogenic effects.
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Carcinoma de Células Escamosas/fisiopatología , Vesículas Extracelulares/fisiología , Células Endoteliales de la Vena Umbilical Humana/fisiología , Neoplasias de la Boca/fisiopatología , Neovascularización Patológica/fisiopatología , Apoptosis , Comunicación Celular , Línea Celular Tumoral , Movimiento Celular , HumanosRESUMEN
Thermus filiformis is an aerobic thermophilic bacterium isolated from a hot spring in New Zealand. The experimental study of the mechanisms of thermal adaptation is important to unveil response strategies of the microorganism to stress. In this study, the main pathways involved on T. filiformis thermoadaptation, as well as, thermozymes with potential biotechnological applications were revealed based on omics approaches. The strategy adopted in this study disclosed that pathways related to the carbohydrate metabolism were affected in response to thermoadaptation. High temperatures triggered oxidative stress, leading to repression of genes involved in glycolysis and the tricarboxylic acid cycle. During heat stress, the glucose metabolism occurred predominantly via the pentose phosphate pathway instead of the glycolysis pathway. Other processes, such as protein degradation, stringent response, and duplication of aminoacyl-tRNA synthetases, were also related to T. filiformis thermoadaptation. The heat-shock response influenced the carotenoid profile of T. filiformis, favoring the synthesis of thermozeaxanthins and thermobiszeaxanthins, which are related to membrane stabilization at high temperatures. Furthermore, antioxidant enzymes correlated with free radical scavenging, including superoxide dismutase, catalase and peroxidase, and metabolites, such as oxaloacetate and α-ketoglutarate, were accumulated at 77 °C.
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Adaptación Fisiológica , Extremófilos/fisiología , Thermus/fisiología , Calor , Espectrometría de Masas , Metabolómica , Proteómica , TranscriptomaRESUMEN
OBJECTIVE: The aim of this study was to evaluate the composition of the salivary pellicle (SP) and multispecies biofilm developed on titanium nitrided by cold plasma. METHODS: Titanium discs were allocated into a control group (Ti) and an experimental group (TiN - titanium-nitrided by cold plasma). The disc surface topography was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The chemical composition of the disc surface was determined by X-ray photoelectron spectroscopy (XPS). Stimulated, clarified, and filtered saliva was used to form pellicles on the discs. Proteome analysis of the adsorbed SP proteins was performed by liquid chromatography-mass spectrometry (LC-MS). The surface free energy (SFE) was evaluated before and after SP formation. A multispecies biofilm composed of Actinomyces naeslundii, Streptococcus oralis, Streptococcus mutans, Fusobacterium nucleatum, Veillonella dispar, and Candida albicans was developed on the SP-coated discs. Viable microorganism counts were determined. The biomass and average thickness of biofilms were analyzed by confocal laser-scanning microscopy (CLSM) with COMSTAT software. The biofilm organization was visualized by SEM. RESULTS: The surface topography was similar in both groups. The SFE of the TiN group did not differ from that of the Ti group (p>0.05), although the adsorption of pellicle proteins increased the SFE in both pellicle-coated groups (p<0.001). Different proteins were identified on the Ti and TiN surfaces. The amount of biofilm was similar for both groups (p=0.416), but the counts of F. nucleatum and S. oralis were higher in the TiN group (p<0.001). Similar biofilms were characterized by the COMSTAT data, CLSM images, and SEM images. CONCLUSION: The titanium nitrided by cold plasma exhibited differences in SP composition and multispecies microbial biofilm population compared to the control titanium surface.
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Biopelículas , Película Dental/química , Película Dental/microbiología , Titanio/química , Microscopía de Fuerza Atómica , Microscopía Confocal , Microscopía Electrónica de Rastreo , Espectroscopía de Fotoelectrones , Gases em Plasma , Proteínas y Péptidos Salivales/química , Programas Informáticos , Propiedades de SuperficieRESUMEN
UNLABELLED: The superoxide dismutase (TfSOD) gene from the extremely thermophilic bacterium Thermus filiformis was cloned and expressed at high levels in mesophilic host. The purified enzyme displayed approximately 25 kDa band in the SDS-PAGE, which was further confirmed as TfSOD by mass spectrometry. The TfSOD was characterized as a cambialistic enzyme once it had enzymatic activity with either manganese or iron as cofactor. TfSOD showed thermostability at 65, 70 and 80°C. The amount of enzyme required to inhibit 50% of pyrogallol autoxidation was 0·41, 0·56 and 13·73 mg at 65, 70 and 80°C, respectively. According to the circular dichroism (CD) spectra data, the secondary structure was progressively lost after increasing the temperature above 70°C. The 3-dimensional model of TfSOD with the predicted cofactor binding corroborated with functional and CD analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: This manuscript describes the expression and characterization of a superoxide dismutase (SOD) from Thermus filiformis with thermophilic and cambialistic characteristics. The SODs are among the most potent antioxidants known in nature, and their stability and pharmacokinetics can vary widely in accordance to their biological source. Although the currently clinical research work has been focused on human and bovine SODs, alternative sources may become more biotechnological attractive in the near future. Our study brings new insights for the research field of antioxidant enzymes with potential application on pharmaceutical, cosmetics and food formulations.
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Superóxido Dismutasa/química , Superóxido Dismutasa/genética , Thermus/enzimología , Thermus/genética , Dicroismo Circular , Clonación Molecular , Coenzimas/metabolismo , Estabilidad de Enzimas , Hierro/metabolismo , Manganeso/metabolismo , Modelos Moleculares , Desnaturalización Proteica , Estructura Secundaria de Proteína , Superóxido Dismutasa/metabolismo , Temperatura , Thermus/metabolismoRESUMEN
We evaluated, by proteomic analysis, whether the chemical changes provoked on enamel by acidulated phosphate fluoride (APF) application alter the protein composition of acquired enamel pellicle. Enamel slabs, pretreated with distilled water (negative control), phosphoric acid (active control) or APF solution, were immersed in human saliva for pellicle formation. The adsorbed proteins were extracted and analyzed by liquid chromatography-mass spectrometry/mass spectrometry. Fifty-six proteins were identified, 12 exclusive to APF and 11 to phosphoric acid. APF decreased the concentration of histatin-1, but increased the concentration of S100-A9, which is confirmed by immunoblotting. The findings suggest that APF application changes the acquired enamel pellicle composition.
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Fluoruro de Fosfato Acidulado/farmacología , Fluoruro de Calcio/farmacología , Proteínas del Esmalte Dental/efectos de los fármacos , Película Dental/química , Película Dental/efectos de los fármacos , Animales , Calgranulina B/análisis , Bovinos , Cromatografía Liquida , Proteínas del Esmalte Dental/análisis , Histatinas/análisis , Humanos , Espectrometría de Masas/métodosRESUMEN
Plant cell wall degrading enzymes are key technological components in biomass bioconversion platforms for lignocellulosic materials transformation. Cost effective production of enzymes and identification of efficient degradation routes are two economic bottlenecks that currently limit the use of renewable feedstocks through an environmental friendly pathway. The present study describes the hypersecretion of an endo-xylanase (GH11) and an arabinofuranosidase (GH54) by a fungal expression system with potential biotechnological application, along with comprehensive characterization of both enzymes, including spectrometric analysis of thermal denaturation, biochemical characterization and mode of action description. The synergistic effect of these enzymes on natural substrates such as sugarcane bagasse, demonstrated the biotechnological potential of using GH11 and GH54 for production of probiotic xylooligosaccharides from plant biomass. Our findings shed light on enzymatic mechanisms for xylooligosaccharide production, as well as provide basis for further studies for the development of novel enzymatic routes for use in biomass-to-bioethanol applications.
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Aspergillus/enzimología , Endo-1,4-beta Xilanasas/metabolismo , Proteínas Fúngicas/metabolismo , Glucuronatos/biosíntesis , Glicósido Hidrolasas/metabolismo , Oligosacáridos/biosíntesis , Penicillium/enzimología , Aspergillus/genética , Endo-1,4-beta Xilanasas/genética , Proteínas Fúngicas/genética , Glucuronatos/aislamiento & purificación , Glicósido Hidrolasas/genética , Oligosacáridos/aislamiento & purificación , Penicillium/genética , Ingeniería de Proteínas/métodosRESUMEN
To evaluate whether protein changes in extracellular matrix of dental biofilm are a unique property of sucrose, this in situ study was conducted using as active control glucose and fructose, the sucrose monosaccharide constituents. Proteins were analyzed by two-dimensional electrophoresis followed by LC-MS/MS after trypsin digestion. Absence or lower abundance of calcium-binding proteins and higher abundance of prolactin-induced proteins were found in biofilm formed in the presence of sucrose or its monosaccharide constituents compared with water, the negative control group. The data suggest that besides sucrose, other dietary carbohydrates may also provoke a change in the protein profile of extracellular matrix of dental biofilm formed.
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Biopelículas , Carbohidratos de la Dieta/farmacología , Proteínas de la Matriz Extracelular/análisis , Fructosa/farmacología , Glucosa/farmacología , Proteoma/análisis , Adulto , Biopelículas/efectos de los fármacos , Proteínas de Unión al Calcio/análisis , Calgranulina B/análisis , Proteínas Portadoras/análisis , Cromatografía Liquida , Estudios Cruzados , Electroforesis en Gel Bidimensional , Proteínas de la Matriz Extracelular/efectos de los fármacos , Glicoproteínas/análisis , Humanos , Focalización Isoeléctrica , Proteínas de Transporte de Membrana , Proteínas y Péptidos Salivales/análisis , Sacarosa/farmacología , Espectrometría de Masas en Tándem , Tripsina , AguaRESUMEN
The human proteins FEZ1 (fasciculation and elongation protein zeta 1) and FEZ2 are orthologs of the protein UNC-76 from C. elegans, involved in the growth and fasciculation of the worms axon. Pull down assays showed that the protein FEZ1 interacts with other proteins (e.g., the protein SCOCO, short coiled-coil protein), mitochondria, and vesicles. These components may therefore represent cargoes to be transported along the microtubule, and the transport may be mediated through FEZ1 reported binding to kinesins (KIF3A). We previously showed that FEZ1 dimerizes in its N-terminal region and interacts with other proteins, including the candidate cargoe proteins, through its C-terminus. Here, we studied the fragment FEZ1(92-194) as well as full-length 6xHis-FEZ1 (1-392) in vitro and endogenous FEZ1 isolated from HEK 293 cells and were able to demonstrate the formation of an intermolecular disulfide bond through FEZ1 Cys-133, which appears to be essential for dimerization. This disulfide bond may be important for the FEZ1 role as a dimeric and bivalent transport adaptor molecule, since it establishes a strong link between the monomers, which could be a prerequisite for the simultaneous binding of two cargoes.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/química , Disulfuros/química , Proteínas del Tejido Nervioso/química , Proteómica/métodos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Secuencia de Aminoácidos , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/metabolismo , Línea Celular , Secuencia Conservada , Disulfuros/metabolismo , Humanos , Espectrometría de Masas , Modelos Moleculares , Anotación de Secuencia Molecular , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Multimerización de Proteína , Estructura Terciaria de Proteína , Transporte de Proteínas , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Dispersión del Ángulo Pequeño , Alineación de Secuencia , Difracción de Rayos XRESUMEN
Previous studies have shown that sucrose promotes changes in the composition of the extracellular matrix (ECM) of plaque-like biofilm (PLB), but its effect on protein expression has not been studied in vivo. Therefore, the protein compositions of ECM of PLB formed with and without sucrose exposure were analyzed by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). For this purpose, a crossover study was conducted during two phases of 14 days each, during which a volunteer wore a palatal appliance containing eight enamel blocks for PLB accumulation. In each phase, a 20% sucrose solution or distilled and deionized water (control) were extraorally dripped onto the blocks 8x/day. On the 14th day, the PLB were collected, the ECM proteins were extracted, separated by two-dimensional gel electrophoresis, digested by in-gel trypsin and MALDI-TOF MS analyzed. In the ECM of PLB formed under sucrose exposure, the following changes compared with the control PLB were observed: (1) the presence of upregulated proteins that may be involved in bacterial response to environmental changes induced by sucrose and (2) the absence of calcium-binding proteins that may partly explain the low inorganic concentration found in ECM of PLB formed under sucrose exposure. The findings showing that sucrose affected the ECM protein composition of PLB in vivo provide further insight into the unique cariogenic properties of this dietary carbohydrate.
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Biopelículas/efectos de los fármacos , Cariogénicos/farmacología , Placa Dental/microbiología , Matriz Extracelular/efectos de los fármacos , Proteoma/análisis , Sacarosa/farmacología , Adulto , Proteínas Bacterianas/análisis , Proteínas de Unión al Calcio/análisis , Estudios Cruzados , Esmalte Dental/microbiología , Placa Dental/química , Electroforesis en Gel Bidimensional , Matriz Extracelular/química , Humanos , Concentración de Iones de Hidrógeno , Isoformas de Proteínas/análisis , Proteoma/efectos de los fármacos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
BACKGROUND: The hemostatic system is the major target of snake venom serine proteinases (SVSPs) that act on substrates of the coagulation, fibrinolytic and kallikrein-kinin systems. Bothrops protease A (BPA), the most glycosylated SVSP, is a non-coagulant, thermostable enzyme. A cDNA encoding BPA showed that the protein has a calculated molecular mass of 25 409 Da, implying that approximately 62% of its molecular mass as assessed by sodium dodecylsulfate polyacrylamide gel electrophoresis (67 kDa) is due to carbohydrate moieties. RESULTS: Here we show that BPA is a potent fibrinogenolytic agent in vitro, as it readily degraded human and rat fibrinogen at a very low enzyme concentration. Partially N-deglycosylated BPA (p-N-d-BPA) generated similar fibrinogen products, but with enhanced fibrinogenolytic activity. In vivo, injection of 0.75 nmoles of BPA in rats completely avoided thrombus formation induced by stasis in the vena cava, or by endothelium injury in the jugular vein. Moreover, it decreased the fibrinogen plasma level and prolonged the recalcification time. Cleavage of fibrinogen in human and rat plasma was observed with native BPA and p-N-d-BPA by electrophoresis followed by western blot using an anti-fibrinogen antibody. BPA did not cause unspecific degradation of plasma proteins and did not cleave isolated albumin, vitronectin and fibronectin at the same concentration used with fibrinogen. Serine proteinase inhibitors failed to inhibit BPA, probably due to steric hindrance caused by its huge carbohydrate moieties. CONCLUSIONS: To the best of our knowledge, this investigation underscores a new, thermostable, specific defibrinogenating agent that may have an application in the prevention of thrombus formation.
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Fibrinolíticos/farmacología , Serina Endopeptidasas/metabolismo , Serina Endopeptidasas/farmacología , Venenos de Serpiente/enzimología , Venenos de Serpiente/farmacología , Animales , Fibrinógeno/metabolismo , Fibrinolíticos/química , Glicosilación , Humanos , Técnicas In Vitro , Masculino , Ratas , Ratas Wistar , Serina Endopeptidasas/química , Inhibidores de Serina Proteinasa/farmacología , Venenos de Serpiente/química , Especificidad por Sustrato , Trombosis/prevención & controlRESUMEN
The aim of this study was to investigate the temporal relationship between changes in biofilm composition and enamel demineralization following exposure to sucrose. A crossover blind study was conducted in situ in three phases, during which 12 volunteers, divided into three groups, subjected enamel slabs 8 times/day to water (negative control), 10% glucose + 10% fructose (active control) or 20% sucrose solution. Biofilms accumulated for 3, 7 and 14 days were collected and analyzed biochemically and microbiologically, and mineral loss from enamel (deltaZ) was evaluated. Significantly higher deltaZ was found in the sucrose group after 7 days. However, on the 3rd day, lactobacilli, insoluble extracellular polysaccharide (EPS) and intracellular polysaccharide were significantly higher, and the calcium, inorganic phosphorus and fluoride concentrations in the biofilm were significantly lower in the sucrose group than in the negative controls. The only significant difference compared to glucose + fructose treatment was a higher insoluble EPS concentration. The data suggest that, although sucrose induces significant enamel demineralization only after 7 days of biofilm accumulation, changes in the biofilm composition are observed earlier.
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Biopelículas , Polisacáridos Bacterianos/análisis , Sacarosa/efectos adversos , Edulcorantes/efectos adversos , Desmineralización Dental/inducido químicamente , Adolescente , Adulto , Análisis de Varianza , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Estudios Cruzados , Esmalte Dental/química , Fructosa/efectos adversos , Glucosa/efectos adversos , Dureza , Humanos , Método Simple Ciego , Factores de Tiempo , Desmineralización Dental/microbiologíaRESUMEN
Dental caries is a biofilm-dependent oral disease, and fermentable dietary carbohydrates are the key environmental factors involved in its initiation and development. However, among the carbohydrates, sucrose is considered the most cariogenic, because, in addition to being fermented by oral bacteria, it is a substrate for the synthesis of extracellular (EPS) and intracellular (IPS) polysaccharides. Therefore, while the low pH environment triggers the shift of the resident plaque microflora to a more cariogenic one, EPS promote changes in the composition of the biofilms' matrix. Furthermore, it has recently been shown that the biofilm formed in the presence of sucrose presents low concentrations of Ca, P(i), and F, which are critical ions involved in de- and remineralization of enamel and dentin in the oral environment. Thus, the aim of this review is to explore the broad role of sucrose in the cariogenicity of biofilms, and to present a new insight into its influence on the pathogenesis of dental caries.
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Biopelículas , Cariogénicos/efectos adversos , Caries Dental/etiología , Sacarosa en la Dieta/efectos adversos , Polisacáridos/metabolismo , Cariogénicos/metabolismo , Esmalte Dental/metabolismo , Placa Dental/complicaciones , Placa Dental/metabolismo , Sacarosa en la Dieta/metabolismo , Humanos , Desmineralización Dental/etiología , Desmineralización Dental/metabolismoRESUMEN
We investigated the putative toxins of Philodryas olfersii (Colubridae), a representative of a family of snakes neglected in venom studies despite their growing medical importance. Transcriptomic data of the venom gland complemented by proteomic analysis of the gland secretion revealed the presence of major toxin classes from the Viperidae family, including serine proteases, metalloproteases, C-type lectins, Crisps, and a C-type natriuretic peptide (CNP). Interestingly, the phylogenetic analysis of the CNP precursor showed it as a linker between two related precursors found in Viperidae and Elapidae snakes. We suggest that these precursors constitute a monophyletic group derived from the vertebrate CNPs.
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Animales , Colubridae/clasificación , Colubridae/metabolismo , Proteoma/clasificación , Proteoma/química , Venenos de Serpiente/análisis , Datos de Secuencia Molecular , Lectinas Tipo C/análisis , Lectinas Tipo C/química , Oligopéptidos/genética , Oligopéptidos/química , Serina Endopeptidasas/análisis , Serina Endopeptidasas/químicaRESUMEN
Since the effect of iron (Fe) on the cariogenicity of sucrose in humans is unexplored, this study assessed in situ the effect of Fe co-crystallized with sucrose (Fe-sucrose) topically applied in vitro on the acidogenicity, biochemical and microbiological composition of the dental biofilm formed in vivo and on the demineralization of the enamel. During two phases of 14 days each, 16 volunteers wore palatal appliances containing blocks of human enamel, which were submitted to four groups of separate treatments: (1) water; (2) 20% sucrose; (3) 20% (w/v) sucrose plus 18 microg Fe/ml, and (4) 20% (w/v) sucrose plus 70 microg Fe/ml. The solutions were dripped onto the blocks 8 times per day. The biofilms formed on the blocks were analyzed with respect to acidogenicity, biochemical and microbiological composition. Mineral loss was determined on enamel by surface and cross-sectional microhardness. Lower demineralization was found in the blocks subjected to Fe-sucrose (70 microg Fe/ml) than in those treated with sucrose (p < 0.05). This concentration of Fe also reduced significantly the populations of mutans streptococci in the biofilm formed on the blocks. In conclusion, our data suggest that Fe may reduce in situ the cariogenic potential of sucrose and the effect seems to be related to the reduction in the populations of mutans streptococci in the dental biofilm formed.
Asunto(s)
Biopelículas/efectos de los fármacos , Cariostáticos/uso terapéutico , Esmalte Dental/microbiología , Compuestos Férricos/uso terapéutico , Desmineralización Dental/prevención & control , Ácidos , Adulto , Biopelículas/crecimiento & desarrollo , Cariogénicos/efectos adversos , Recuento de Colonia Microbiana , Sacarato de Óxido Férrico , Ácido Glucárico , Dureza , Humanos , Concentración de Iones de Hidrógeno , Lactobacillus/crecimiento & desarrollo , Lactobacillus/fisiología , Minerales/análisis , Método Simple Ciego , Streptococcus/crecimiento & desarrollo , Streptococcus/fisiología , Streptococcus mutans/crecimiento & desarrollo , Streptococcus mutans/fisiología , Sacarosa/efectos adversosRESUMEN
Since the importance of luting cement on secondary caries in enamel and dentin is unknown, an in situ crossover study was conducted in three phases over 21 days using a fluoride-containing toothpaste. One hundred and twenty-six metallic restorations were cemented into the dentinoenamel junction of slabs of human teeth with zinc phosphate (ZP), resin-modified glass ionomer (GI) or resinous cement (RC). The slabs were inserted onto flanges of the removable partial acrylic dentures of 14 volunteers and covered with gauze to enhance dental plaque accumulation. The volunteers used fluoride toothpaste (1.100 microg F/g, w/w). After 21 days, the biofilm that formed on the slabs was collected for biochemical and microbiological analyses, and the demineralization in enamel-dentin around the restorations was evaluated. The fluoride concentration of biofilm in the GI group was higher (p<0.05) than the ZP and RC groups. Also, the concentration of Zinc in biofilm formed on the slabs cemented with ZP was higher (p<0.05) than the other groups. However, the effect of the luting material on enamel or dentin demineralization was not statistically significant (p>0.05). The data suggest that when fluoride toothpaste is used, the anticariogenic property of the luting cement may not be relevant to the reduction of secondary caries.
Asunto(s)
Biopelículas , Aleaciones Dentales/química , Caries Dental/microbiología , Cementos Dentales/química , Restauración Dental Permanente , Streptococcus mutans/fisiología , Adulto , Cariostáticos/química , Cariostáticos/uso terapéutico , Recuento de Colonia Microbiana , Estudios Cruzados , Caries Dental/etiología , Esmalte Dental/microbiología , Placa Dental/microbiología , Dentina/microbiología , Fluoruros/química , Fluoruros/uso terapéutico , Cementos de Ionómero Vítreo/química , Humanos , Persona de Mediana Edad , Cementos de Resina/química , Acero Inoxidable/química , Streptococcus mutans/crecimiento & desarrollo , Desmineralización Dental/etiología , Desmineralización Dental/microbiología , Pastas de Dientes/uso terapéutico , Zinc/química , Cemento de Fosfato de Zinc/químicaRESUMEN
Since the effect of the combination of methods of fluoride use on enamel demineralization and on plaque composition is not clearly established, this study examined the effect of the combination of acidulated phosphate fluoride (APF) application and F dentifrice on enamel demineralization and on plaque composition. In this crossover study, 16 volunteers, wearing a palatal appliance containing bovine enamel blocks, were subjected to 4 treatment groups: non-fluoridated dentifrice (PD), FD, APF+PD, and APF+FD. The APF was applied to the enamel before the 14-day experimental period. During the experimental period, test dentifrices were applied 3x/day, and a 20% sucrose solution was applied 4x and 8x/day by being dripped on the blocks. Although APF application was able either to increase F concentration in plaque or to reduce the % of mutans streptococci, its combination with F dentifrice use neither reduced enamel mineral loss nor changed any other measured plaque variable with respect to the FD group alone.
Asunto(s)
Fluoruro de Fosfato Acidulado/uso terapéutico , Cariogénicos/efectos adversos , Cariostáticos/uso terapéutico , Esmalte Dental/efectos de los fármacos , Placa Dental/química , Dentífricos/uso terapéutico , Fluoruros/uso terapéutico , Sacarosa/efectos adversos , Desmineralización Dental/etiología , Adulto , Análisis de Varianza , Animales , Calcio/análisis , Cariostáticos/análisis , Bovinos , Estudios Cruzados , Esmalte Dental/patología , Placa Dental/microbiología , Fluoruros/análisis , Dureza , Humanos , Fósforo/análisis , Placebos , Método Simple Ciego , Streptococcus mutans/efectos de los fármacosRESUMEN
Since the use of bovine instead of human dentine to evaluate cariogenic and anticariogenic substances is not well established, this in situ study was conducted. Eleven volunteers wore palatal acrylic devices containing 4 dentine slabs (2 human and 2 bovine). Sucrose solution (20%) was dripped over all slabs 4 times a day, simulating a cariogenic challenge. Dentifrice slurries, fluoridated or not, were dripped over specified dentine slabs 3 times a day to evaluate caries reduction. After 14 days, the biofilm formed on the dentine slabs was collected for microbiological analysis. In dentine, mineral loss (DeltaZ) and lesion depth (LD) were determined by cross-sectional microhardness and by polarized light microscopy, respectively. The total streptococci and mutans streptococci counts in the biofilm formed either on human or on bovine slabs, whether treated or not with fluoride dentifrice, were not statistically different. The DeltaZ and the LD values of dentine treated with fluoride dentifrice were significantly lower than the values of dentine treated with non-fluoride dentifrice. The differences in the DeltaZ and LD values between the human and bovine dentine were not statistically significant. The results suggest that bovine dentine can be used instead of human to evaluate caries development and inhibition.