RESUMO
Cariogenic biofilms have a matrix rich in exopolysaccharides (EPS), mutans and dextrans, that contribute to caries development. Although several physical and chemical treatments can be employed to remove oral biofilms, those are only partly efficient and use of biofilm-degrading enzymes represents an exciting opportunity to improve the performance of oral hygiene products. In the present study, a member of a glycosyl hydrolase family 66 from Flavobacterium johnsoniae (FjGH66) was heterologously expressed and biochemically characterized. The recombinant FjGH66 showed a hydrolytic activity against an early EPS-containing S. mutans biofilm, and, when associated with a α-(1,3)-glucosyl hydrolase (mutanase) from GH87 family, displayed outstanding performance, removing more than 80% of the plate-adhered biofilm. The mixture containing FjGH66 and Prevotella melaninogenica GH87 α-1,3-mutanase was added to a commercial mouthwash liquid to synergistically remove the biofilm. Dental floss and polyethylene disks coated with biofilm-degrading enzymes also degraded plate-adhered biofilm with a high efficiency. The results presented in this study might be valuable for future development of novel oral hygiene products.
Assuntos
Biofilmes , Dextranase , Flavobacterium , Glicosídeo Hidrolases , Streptococcus mutans , Biofilmes/crescimento & desenvolvimento , Dextranase/metabolismo , Dextranase/genética , Flavobacterium/enzimologia , Flavobacterium/genética , Streptococcus mutans/enzimologia , Streptococcus mutans/genética , Glicosídeo Hidrolases/metabolismo , Glicosídeo Hidrolases/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Hidrólise , Biotecnologia/métodosRESUMO
STATEMENT OF PROBLEM: Conventional analog methods have been replaced with digital methods for removable partial denture (RPD) frameworks. However, limited information is available regarding the build direction of RPD frameworks and its effect on properties. PURPOSE: The purpose of this in vitro study was to evaluate the mechanical and surface properties of the cobalt chromium (Co-Cr) alloy produced at different build angles by the laser powder bed fusion additive manufacturing (AM) technology used for RPD framework fabrication. MATERIAL AND METHODS: Plate-shaped Co-Cr specimens (n=6) were produced by the AM technology and divided into 3 groups depending on the build angle (0, 45, or 90 degrees). The elastic modulus and fracture properties were evaluated by flexural testing. Additionally, 15 disks were printed by using the same parameters of the plates (n=5) to analyze the surface hardness with microhardness testing, and surface properties were determined by surface free energy by using the contact angle and surface roughness measured by using a profilometer. Twelve Co-Cr cylindrical specimens were produced by using the same parameters (n=4), and their microstructure was examined by using an optical microscope. One-way ANOVA was used to evaluate the overall effects of the interaction between groups, and the Tukey test was applied when the interaction was statistically significant (α=.05). RESULTS: The flexural strength showed a statistically significant difference (P<.05), with the peak value exhibited by the 0-degree group. A statistical difference was also observed between the angulation and modulus of elasticity; however, the highest value was exhibited by the 45-degree group. For the fracture topography, all groups observed a dimple-like fracture, although the 45-degree group showed wider cleavage planes of fractures than other angulations. For microhardness, the 0- and 45-degree groups exhibited a statistical difference in relation to the 90-degree group (P<.05). For surface properties, no statistically significant difference (P>.05) was found in any of the evaluated parameters. Dependence on the build angles was evidenced by the molten pool boundaries during observation of the microstructure. CONCLUSIONS: The build angle influenced the flexural strength and microhardness of the Co-Cr alloy produced by AM; however, it does not affect surface free energy and surface roughness.
Assuntos
Prótese Parcial Removível , Ligas de Cromo/química , Elasticidade , Módulo de Elasticidade , Propriedades de Superfície , Teste de MateriaisRESUMO
Dental biofilms represent a serious oral health problem playing a key role in the development of caries and other oral diseases. In the present work, we cloned and expressed in E. coli two glucanases, Prevotella melaninogenica mutanase (PmGH87) and Capnocytophaga ochracea dextranase (CoGH66), and characterized them biochemically and biophysically. Their three-dimensional structures were elucidated and discussed. Furthermore, we tested the capacity of the enzymes to hydrolyze mutan and dextran to prevent formation of Streptococcus mutans biofilms, as well as to degrade pre- formed biofilms in low and abundant sugar conditions. The percentage of residual biofilm was calculated for each treatment group in relation to the control, as well as the degree of synergism. Our results suggest that both PmGH87 and CoGH66 are capable of inhibiting biofilm formation grown under limited or abundant sucrose conditions. Degradation of pre-formed biofilms experiments reveal a time-dependent effect for the treatment with each enzyme alone. In addition, a synergistic and dose-dependent effects of the combined enzymatic treatment with the enzymes were observed. For instance, the highest biomass degradation was 95.5% after 30 min treatment for the biofilm grown in low sucrose concentration, and 93.8% after 2 h treatment for the biofilm grown in sugar abundant condition. Strong synergistic effects were observed, with calculated degree of synergism of 5.54 and 3.18, respectively and their structural basis was discussed. Jointly, these data can pave the ground for the development of biomedical applications of the enzymes for controlling growth and promoting degradation of established oral biofilms.
Assuntos
Escherichia coli , Prevotella melaninogenica , Escherichia coli/genética , Biofilmes , SacaroseRESUMO
Fluoride chemically soluble in toothpaste is an indicator of fluoride bioavailability when the teeth are brushed, and the same should be expected systemically when toothpaste is ingested. A 4-phases study was conducted, in which 8 participants were subjected in each phase to one of the assigned treatment groups: group I: fresh sample of a Na2FPO3/CaCO3 toothpaste with 1,334 µg F/g of total soluble fluoride (TSF) and groups II-IV: aged samples of toothpaste presenting TSF concentrations of 1,128, 808, and 687 µg F/g, respectively. In all phases, the participants ingested an amount of toothpaste equivalent to 70.0 µg F/kg body weight, as total fluoride (TF). Blood was collected before (baseline) and up to 180 min after toothpaste ingestion as indicator of fluoride bioavailability. Total urine (24 h before and 24 h after ingestion) was collected as indicator of absorbed fluoride that was excreted. F concentration in blood plasma and urine was determined with a fluoride ion-specific electrode. The areas under the curve (AUC) of F concentration versus time (AUC = ng F/mL × min) and the peaks of fluoride concentration in blood plasma (Cmax) were calculated. The net amount of fluoride excreted (mg/day) was calculated by subtraction. A significant correlation of the amount (mg) of TSF ingested was found between the AUC (r = 0.76; p < 0.01) and Cmax (r = 0.86; p < 0.01) in plasma, and the fluoride excreted (r = 0.65; p < 0.01). For TF, no statistical correlations were found (p > 0.05). Data suggest that the concentration of TSF found in Na2FPO3/CaCO3-based toothpastes is a useful predictor of how much fluoride will be systemically bioavailable when this type of formulation is ingested.
Assuntos
Fluoretos , Cremes Dentais , Idoso , Disponibilidade Biológica , Peso Corporal , Carbonato de Cálcio , HumanosRESUMO
We have hypothesized that the association between human milk and caries in breastfeeding children could be explained by the combination of a diurnal cariogenic diet with the nocturnal lactose fermentation, conditions simulated in this experimental study. Cariogenic biofilm was formed on bovine enamel slabs, which were exposed 8x/day for 3 min to a 10% sucrose solution, simulating a highly cariogenic diurnal diet, or 50 mM NaCl solution (control). Simulating the nocturnal retention of milk in mouth, biofilms were transferred to culture medium containing 0.7% lactose for 2 h, or only to culture medium (control). Four groups were designed (n = 12): Ctrl, no exposure to diurnal sucrose or nocturnal lactose; Lac, only nocturnal exposure to lactose (2 h); Suc, only diurnal exposure to sucrose (8x/day); and SucâLac, diurnal exposure to sucrose (8x/day) followed by nocturnal exposure to lactose (2 h). The medium was changed 3x/day, at the beginning of the day and after diurnal and nocturnal exposures. Calcium in the medium was determined as a chemical indicator of partial demineralizations occurred during the diurnal and the nocturnal treatments; the medium pH was also determined. After 96 h of growth, biofilms were harvested to evaluate CFU, biomass, and extracellular polysaccharides, soluble and insoluble. The percentage of enamel surface hardness loss (%SHL) was evaluated as cumulative demineralization. Data were analyzed by one-way ANOVA and Tukey's test (α = 5%). Highest %SHL (p < 0.05) was found for the SucâLac (40.6%) group when compared to Suc (32.1%), Lac (6.6%), and Ctrl (2.4%) groups. Calcium released during the diurnal and nocturnal treatments was, respectively, SucâLac = Suc > Lac = Ctrl and SucâLac > Lac > Suc = Ctrl (p < 0.05). Regarding the Ctrl group, calcium released from nocturnal lactose fermentation by the SucâLac group was 4-fold greater than that provoked by the Lac group. The findings were supported by the pH of the media. The data suggest that the biofilm formed under diurnal exposure to sucrose enhances the cariogenicity of nocturnal exposure to lactose.
Assuntos
Cárie Dentária , Desmineralização do Dente , Animais , Biofilmes , Cálcio/farmacologia , Bovinos , Criança , Cárie Dentária/etiologia , Esmalte Dentário , Humanos , Lactose/farmacologia , Streptococcus mutans , Sacarose/efeitos adversosRESUMO
OBJECTIVE: This in situ study evaluated the effect of high-fluoride dentifrice (5000 µg F-/g) and fluoride-containing bonding composite resin on enamel demineralization adjacent to orthodontic brackets. METHODS: Ten volunteers wore palatal appliances containing bovine enamel blocks with metallic brackets bonded with fluoride-free or fluoride-containing composite resin. During three phases of 14 days each, three dentifrices with different fluoride concentrations (0, 1100, and 5000 µg F-/g) were tested. The cariogenic challenge consisted of 20% sucrose solution dripped 8x/day onto the dental blocks. At the end of each phase, biofilm formed was collected for fluoride analysis. Cross section hardness was performed in enamel blocks, and the lesion area was calculated. Data were analyzed by two-way ANOVA followed by Tukey post hoc test (α = 5%). RESULTS: The only signicant factor for all the variables under study was the dentifrice. Smaller lesion area and higher fluoride concentration on biofilm were found in 5000 µg F-/g group, irrespective of bonding composite resin (p < 0.001). Neither bracket-bonding composite resin nor the interaction between the factors was statistically significant (p > 0.05) for all the variables. CONCLUSION: High-fluoride dentifrice is effective in reducing demineralization on enamel adjacent to orthodontic brackets, while the fluoride-containing bonding composite resin does not influence it. CLINICAL SIGNIFICANCE: Since high-fluoride dentifrice was able to reduce demineralization adjacent to brackets, it can be an option to caries management in orthodontics patients.
Assuntos
Dentifrícios , Braquetes Ortodônticos , Desmineralização do Dente , Animais , Cariostáticos , Bovinos , Esmalte Dentário , Fluoretos , Humanos , Desmineralização do Dente/prevenção & controleRESUMO
The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.
Assuntos
Ligas/química , Película Dentária/química , Nióbio/química , Proteoma/análise , Proteínas e Peptídeos Salivares/análise , Titânio/química , Zircônio/química , Adsorção , Aderência Bacteriana , Materiais Biocompatíveis/química , ProteômicaRESUMO
Extracellular polysaccharides (EPS) could increase the penetration of fluoride through dental biofilm, reducing its cariogenicity. We measured the concentration of fluoride in EPS-containing (EPS+) or not-containing (EPS-) Streptococcus mutans bacterial pellets resembling test biofilms, before and up to 60 min after a 0.05% NaF rinse in situ. Fluoride penetration and clearance were higher in EPS+ bacterial pellets. The data suggest that EPS enhances fluoride penetration, but also accelerates fluoride clearance from dental biofilms.
Assuntos
Biofilmes/efeitos dos fármacos , Cariostáticos/química , Fluoretos/química , Polissacarídeos Bacterianos/química , Streptococcus mutans/efeitos dos fármacos , Adulto , Cariostáticos/farmacologia , Estudos Cross-Over , Cárie Dentária/microbiologia , Difusão , Método Duplo-Cego , Fluoretos/farmacologia , Frutose/química , Glucose/química , Humanos , Concentração Osmolar , Análise de Regressão , Saliva/fisiologia , Estatísticas não Paramétricas , Streptococcus mutans/fisiologia , Sacarose/químicaRESUMO
This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.
Assuntos
Ligas , Biofilmes/efeitos dos fármacos , Clorexidina/farmacologia , Próteses e Implantes/microbiologia , Titânio , Zircônio , Relação Dose-Resposta a DrogaRESUMO
Since there is no consensus about whether starch increases the cariogenic potential of sucrose, we used a validated 3-species biofilm model to evaluate if starch combined with sucrose provokes higher root dentine demineralization than sucrose alone. Biofilms (n = 18) composed by Streptococcus mutans (the most cariogenic bacteria), Actinomces naeslundii (which has amylolytic activity), and Streptococcus gordonii (which binds salivary amylase) were formed on root dentine slabs under exposure 8 ×/day to one of the following treatments: 0.9% NaCl, 1% starch, 10% sucrose, or a combination of 1% starch and 10% sucrose. Before each treatment, biofilms were pretreated with human whole saliva for 1 min. The pH of the culture medium was measured daily as an indicator of biofilm acidogenicity. After 96 h of growth, the biofilms were collected, and the biomass, bacteria viability, and polysaccharides were analyzed. Dentine demineralization was assessed by surface hardness loss (% SHL). Biofilm bioarchitecture was analyzed using confocal laser scanning microscopy. Treatment with a starch and sucrose combination provoked higher (p = 0.01) dentine demineralization than sucrose alone (% SHL = 53.2 ± 7.0 vs. 43.2 ± 8.7). This was supported by lower pH values (p = 0.007) of the culture medium after daily exposure to the starch and sucrose combination compared with sucrose (4.89 ± 0.29 vs. 5.19 ± 0.32). Microbiological and biochemical findings did not differ between biofilms treated with the combination of starch and sucrose and sucrose alone (p > 0.05). Our findings give support to the hypothesis that a starch and sucrose combination is more cariogenic for root dentine than sucrose alone.
Assuntos
Dentina/fisiopatologia , Sacarose Alimentar/efeitos adversos , Cárie Radicular/etiologia , Amido/efeitos adversos , Desmineralização do Dente/etiologia , Raiz Dentária/fisiopatologia , Actinomyces/fisiologia , Animais , Biofilmes/crescimento & desenvolvimento , Bovinos , Dentina/diagnóstico por imagem , Dentina/microbiologia , Dureza , Humanos , Concentração de Íons de Hidrogênio , Microscopia Confocal , Modelos Animais , Cárie Radicular/diagnóstico por imagem , Cárie Radicular/microbiologia , Saliva/fisiologia , Streptococcus gordonii/fisiologia , Streptococcus mutans/fisiologia , Propriedades de Superfície , Raiz Dentária/diagnóstico por imagem , Raiz Dentária/microbiologiaRESUMO
STATEMENT OF PROBLEM: Biofilms can reduce the corrosion resistance of titanium because of the bacterial metabolism of fermentable carbohydrates, including sucrose. However, studies evaluating whether biofilms exposed to higher sucrose concentrations can affect the electrochemical behavior of titanium are lacking. PURPOSE: The purpose of this in vitro study was to test the electrochemical behavior of titanium previously exposed to biofilm supplemented with different sucrose concentrations. MATERIAL AND METHODS: Streptococcus mutans UA159 biofilms were formed on commercially pure titanium (cpTi) surfaces and supplemented constantly with different sucrose concentrations (0%, 1%, 10%, and 40%) for 7 days (experimental groups) (n=12 per group). CpTi disks without biofilm were used as a control (n=12). The standard electrochemical tests open-circuit potential, electrochemical impedance spectroscopy, and potentiodynamic curve were performed. Data were submitted to ANOVA and the Tukey honestly significant difference (HSD) tests (α=.05). RESULTS: The biofilm exposed to sucrose had an increased biofilm dry weight (P<.05). The polysaccharide amount and the pH drop were higher in the groups exposed to sucrose (P<.05). No difference was noted between the control and experimental groups for the electrochemical properties of cpTi (P>.05). CONCLUSIONS: Biofilms exposed to greater carbohydrate concentration did not alter the corrosive behavior of titanium.
Assuntos
Biofilmes , Eletroquímica , Teste de Materiais , Sacarose/metabolismo , Titânio/química , Biofilmes/crescimento & desenvolvimento , Corrosão , Implantes Dentários , Materiais Dentários/química , Espectroscopia Dielétrica , Técnicas Eletroquímicas , Concentração de Íons de Hidrogênio , Polissacarídeos/química , Saliva Artificial , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus mutans/metabolismo , Propriedades de Superfície , Fatores de TempoRESUMO
The surface characteristics and electrochemical properties of bioactive coatings produced by plasma electrolytic oxidation (PEO) with calcium, phosphorous, silicon and silver on commercially pure titanium were evaluated. PEO treatment produced a porous oxide layer, which improved the surface topography, and enriched the surface chemistry with bioactive elements, responsible for mimicking bone surface. The surfaces with higher calcium concentration presented antibacterial and biocompability properties with better responses for corrosion and barrier properties, due to the presence of rutile crystalline structure. PEO may be a promising surface treatment option to improve the electrochemical behavior of dental implants mitigating treatment failures.
RESUMO
OBJECTIVE: The aim of this study was to evaluate the effect of daily exposure to a denture cleanser on a multispecies biofilm. MATERIALS AND METHODS: Multispecies biofilms (five bacteria and Candida albicans) were developed for 64.5 h on acrylic resin specimens and randomized into control and experimental groups. In the experimental group, biofilms were immersed in denture cleanser for 3 min/day for seven consecutive days. In the control group, the biofilms were developed with no treatment for the same period. Biofilms from both groups were collected after 1, 4, and 7 days and analyzed for the number of microorganisms and polysaccharide concentrations. Scanning electron microscopy (SEM) and confocal microscopy (CLSM) analyses were performed. RESULTS: The total microorganism counts and bacterial populations were lower in the experimental group compared to the control group for all of the periods evaluated. However, the C. albicans counts continuously increased in all of the cleanser-exposed biofilms, with abundant hyphae forms on SEM and CLSM images. The polysaccharide concentration was significantly higher in the experimental group after 7 days. CONCLUSIONS: Daily exposure of a multispecies biofilm to a denture cleanser reduces the number of total microorganisms but favors C. albicans development. CLINICAL RELEVANCE: Daily use of denture cleanser is an effective method for controlling bacteria in biofilm, but it can potentially select C. albicans, an important etiological agent of oral candidosis.
Assuntos
Biofilmes/efeitos dos fármacos , Higienizadores de Dentadura/farmacologia , Contagem de Colônia Microbiana , Técnicas In Vitro , Microscopia Confocal , Microscopia Eletrônica de Varredura , Fatores de TempoRESUMO
STATEMENT OF PROBLEM: Candida biofilms on denture surfaces are substantially reduced after a single immersion in denture cleanser. However, whether this effect is maintained when dentures are immersed in cleanser daily is unclear. PURPOSE: The purpose of this study was to evaluate the effect of the daily use of enzymatic cleanser on Candida albicans biofilms on denture base materials. MATERIAL AND METHODS: The surfaces of polyamide and poly(methyl methacrylate) resin specimens (n=54) were standardized and divided into 12 groups (n=9 per group), according to study factors (material type, treatment type, and periods of treatment). Candida albicans biofilms were allowed to form over 72 hours, after which the specimens were treated with enzymatic cleanser once daily for 1, 4, or 7 days. Thereafter, residual biofilm was ultrasonically removed and analyzed for viable cells (colony forming units/mm(2)) and enzymatic activity (phospholipase, aspartyl-protease, and hemolysin). Factors that interfered with the response variables were analyzed by 3-way ANOVA with the Holm-Sidak multiple comparison method (α=.05). RESULTS: Polyamide resin presented more viable cells of Candida albicans (P<.001) for both the evaluated treatment types and periods. Although enzymatic cleansing significantly (P<.001) reduced viable cells, daily use did not maintain this reduction (P<.001). Phospholipase activity significantly increased with time (P<.001) for both materials and treatments. However, poly(methyl methacrylate) based resin (P<.001) and enzymatic cleansing treatment (P<.001) contributed to lower phospholipase activity. Aspartyl-protease and hemolysin activities were not influenced by study factors (P>.05). CONCLUSIONS: Although daily use of an enzymatic cleanser reduced the number of viable cells and phospholipase activity, this treatment was not effective against residual biofilm over time.
Assuntos
Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Materiais Dentários/química , Higienizadores de Dentadura/uso terapêutico , Nylons/química , Polimetil Metacrilato/química , Ácido Aspártico Proteases/análise , Boratos/uso terapêutico , Candida albicans/enzimologia , Contagem de Colônia Microbiana , Película Dentária/microbiologia , Proteínas Hemolisinas/análise , Humanos , Imersão , Teste de Materiais , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Fosfolipases/análise , Método Simples-Cego , Sulfatos/uso terapêutico , Propriedades de Superfície , Fatores de TempoRESUMO
AIM: To evaluate the adhesion of mono and duospecies biofilm on a commercially available dental implant surface coated with hydroxyapatite nanoparticles (nanoHA). MATERIAL AND METHODS: Titanium discs were divided into two groups: double acid-etched (AE) and AE coated with nanoHA (NanoHA). Surface characteristics evaluated were morphology, topography, and wettability. Mono and duospecies biofilms of Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans) were formed. Discs were exposed to fetal bovine serum (FBS) to form the pellicle. Biofilm was growth in RPMI1640 medium with 10% FBS and 10% BHI medium for 6 h. Microbial viability was evaluated using colony-forming unit and metabolic activity by a colorimetric assay of the tetrazolium salt XTT. Biofilm architecture and organization were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). RESULTS: AE surface had more pores, while NanoHA had even nanoHA crystals distribution. Roughness was similar (AE: 0.59 ± 0.07 µm, NanoHA: 0.69 ± 0.18 µm), but wettability was different (AE: Θw= 81.79 ± 8.55°, NanoHA: Θw= 53.26 ± 11.86°; P = 0.01). NanoHA had lower S. sanguinis viability in monospecies biofilm (P = 0.007). Metabolic activity was similar among all biofilms. In SEM both surfaces on C. albicans biofilm show a similar distribution of hyphae in mono and duospecies biofilms. AE surface has more S. sanguinis than the NanoHA surface in the duospecies biofilm. CLSM showed a large proportion of live cells in all groups. CONCLUSIONS: The nanoHA surface reduced the adhesion of S. sanguinis biofilm but did not alter the adhesion of C. albicans or the biofilm formed by both species.
Assuntos
Biofilmes , Candida albicans , Implantes Dentários , Durapatita , Microscopia Confocal , Microscopia Eletrônica de Varredura , Nanopartículas , Streptococcus sanguis , Propriedades de Superfície , Titânio , Titânio/química , Titânio/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Biofilmes/efeitos dos fármacos , Durapatita/farmacologia , Durapatita/química , Streptococcus sanguis/efeitos dos fármacos , Nanopartículas/química , Implantes Dentários/microbiologia , Técnicas In Vitro , Aderência Bacteriana/efeitos dos fármacos , Molhabilidade , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Condicionamento Ácido do Dente , Viabilidade Microbiana/efeitos dos fármacosRESUMO
Despite all the current knowledge in cariology, research is still being carried out nowadays trying to make dental enamel resistant to dental caries. Since enamel is mainly composed by a mineral, efforts have been put together to make it more resistant to acids produced by dental biofilm when exposed to dietary sugars. Fluoride was once thought to be a micronutrient that impacted caries resistance when incorporated in the tooth mineral, but we now know that the complex interactions at the mineral surface are most important. Every slightly soluble mineral, and enamel is no exception, has a behavior that is determined by the environment where it is located, and in the case of the dental crown, saliva and biofilm fluid play an important role. Enamel can keep in balance or lose its minerals, but it can gain them back. These processes, equilibrium, and loss or gain follow Le Chatelier's principle, and physicochemically, they are known as saturating, undersaturating, and supersaturating conditions, respectively. Saliva, and even the biofilm fluid, is supersaturated with calcium (Ca2+) and phosphate (PO43-) in relation to enamel solubility, and thus the natural tendency of enamel is to gain mineral, conferring saliva with a remineralizing property. However, the decrease in pH and the presence of free fluoride ion (F-) will determine what will happen to the enamel. While lowering the pH of the medium is an imbalance factor, fluoride at micromolar concentration reduces the acid impact. This chapter provides an updated, evidence-based understanding of the interactions between enamel and oral fluids.
Assuntos
Cárie Dentária , Desmineralização do Dente , Humanos , Fluoretos/farmacologia , Fluoretos/análise , Fluoretos/química , Esmalte Dentário/química , Minerais/análise , Concentração de Íons de Hidrogênio , Remineralização Dentária , Cariostáticos/análiseRESUMO
OBJECTIVE: To evaluate the influence of Streptococcus oralis supernatant on the proliferation and virulence of Candida albicans. DESIGN: S. oralis supernatant was obtained by filtration of overnight cultures. Single or dual-species cultures of C. albicans and S. oralis were cultivated in both planktonic and biofilm-based models. Planktonic culture growth was measured, and mature biofilms formed on resin disks were collected to measure biofilm metabolic activity, total biomass, and cell counts. Hyphae formation (virulence factor) and biofilm thickness were analyzed by confocal laser scanning microscopy. Data were analyzed by a one-way ANOVA test followed by the Tukey posthoc test (α = 0.05). RESULTS: We found that S. oralis supernatant did not influence C. albicans proliferation in planktonic cultures. However, biofilms containing S. oralis supernatant showed higher cell metabolism than C. albicans monoculture biofilms and C. albicans-S. oralis dual-culture biofilms (p < 0.05). Though S. oralis supernatants did increase biofilm metabolic activity, they did not affect the total biomass and cell counts of C. albicans (p > 0.05). However, biofilm imaging revealed enhanced C. albicans hyphae formation in biofilms containing S. oralis supernatant compared to C. albicans monoculture biofilms. CONCLUSIONS: Secreted metabolites in S. oralis supernatant may contribute to C. albicans metabolism and virulence.
Assuntos
Candida albicans , Streptococcus oralis , Virulência , Biofilmes , Proliferação de CélulasRESUMO
Candida albicans and Streptococcus mutans are known to synergistically interact with each other in the oral cavity. For example, glucosyltransferase B (GtfB), secreted by S. mutans, can bind to the C. albicans cell surface, promoting dual-species biofilm formation. However, the fungal factors mediating interactions with S. mutans are unknown. The C. albicans adhesins Als1, Als3, and Hwp1 are key players in C. albicans single-species biofilm formation, but their roles, if any, in interacting with S. mutans have not been assessed. Here, we investigated the roles of the C. albicans cell wall adhesins Als1, Als3, and Hwp1 on forming dual-species biofilms with S. mutans. We assessed the abilities of the C. albicans wild-type als1Δ/Δ, als3Δ/Δ, als1Δ/Δ/als3Δ/Δ, and hwp1Δ/Δ strains to form dual-species biofilms with S. mutans by measuring optical density, metabolic activity, cell enumeration, biomass, thickness, and architecture of the biofilms. We observed that the C. albicans wild-type strain formed enhanced dual-species biofilms in the presence of S. mutans in these different biofilm assays, confirming that C. albicans and S. mutans synergistically interact in the context of biofilms. Our results reveal that C. albicans Als1 and Hwp1 are major players in interacting with S. mutans, since dual-species biofilm formation was not enhanced when the als1Δ/Δ or hwp1Δ/Δ strains were cultured with S. mutans in dual-species biofilms. Als3, however, does not seem to play a clear role in interacting with S. mutans in dual-species biofilm formation. Overall, our data suggest that the C. albicans adhesins Als1 and Hwp1 function to modulate interactions with S. mutans and could be potential targets for future therapeutics.
RESUMO
Antifungal agents are widely used to specifically eliminate infections by fungal pathogens. However, the specificity of antifungal agents has been challenged by a few studies demonstrating antibacterial inhibitory effects against Mycobacteria and Streptomyces species. Here, we evaluated for the first time the potential effect of fluconazole, the most clinically used antifungal agent, on a human oral microbiota biofilm model. The results showed that biofilm viability on blood and mitis salivarius agar media was increased over time in the presence of fluconazole at clinically relevant concentrations, despite a reduction in biomass. Targeted PCR revealed a higher abundance of Veillonella atypica, Veillonella dispar, and Lactobacillus spp. in the fluconazole-treated samples compared to the control, while Fusobacterium nucleatum was reduced and Streptococcus spp were not significantly affected. Further, we tested the potential impact of fluconazole using single-species models. Our results, using Streptococcus mutans and Streptococcus mitis luciferase reporters, showed that S. mutans planktonic growth was not significantly affected by fluconazole, whereas for S. mitis, planktonic growth, but not biofilm viability, was inhibited at the highest concentration. Fluconazole's effects on S. mitis biofilm biomass were concentration and time dependent. Exposure for 48 h to the highest concentration of fluconazole was associated with S. mitis biofilms with the most increased biomass. Potential growth inhibitory effects were further tested using four non-streptococcal species. Among these, the planktonic growth of both Escherichia coli and Granulicatella adiacens was inhibited by fluconazole. The data indicate bacterial responses to fluconazole that extend to a broader range of bacterial species than previously anticipated from the literature, with the potential to disturb biofilm communities.
RESUMO
Policy evaluation and guidance on fluoride use and sugar consumption in Latin American and Caribbean countries (LACC) may provide a scientific evidence basis for policymakers, dental professionals, civil society organizations and individuals committed to improving public oral health. A cross-sectional study was conducted to evaluate the extent of implementation of policies/guidelines on fluoride use, and sugar consumption in LACC. The study had two stages. First a questionnaire covering four major areas was developed: fluoridation of public water supplies; salt fluoridation; fluoride dentifrices, and sugar consumption. Then, the questionnaire was applied to collect data among representative participants in public oral health from LACC. Ninety-six participants from 18 LACC answered the questionnaire. One-hundred seventy documents were attached, and 285 links of websites were provided by the respondents. Implementation of policies and guidelines on water and table salt fluoridation and processed and ultra-processed food consumption were found in most countries, with some issues in the consensus and coverage. Thus, differences were identified in the extent of implementation of public oral health strategies on sugar consumption and fluoridation among the countries. There is no consensus on the policies in LACC to reduce sugar consumption and for the use of fluoride. A few policies and guidelines were applied in isolated countries, with a variety of strategies and standards. For future actions, it will be important to encourage the development of strategies and public policies within countries, and to evaluate the effectiveness of existing policies in reducing dental caries and in improving oral health in LACC.