RESUMEN
Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge.
Asunto(s)
Biopelículas/efectos de los fármacos , Caries Dental/microbiología , Streptococcus mutans/efectos de los fármacos , Edulcorantes/farmacología , Proteínas Bacterianas/análisis , Técnicas Bacteriológicas , Biopelículas/crecimiento & desarrollo , Biomasa , Cariogénicos/farmacología , Proteínas Portadoras/análisis , Medios de Cultivo , Esmalte Dental/microbiología , Perfilación de la Expresión Génica , Glucosa/farmacología , Glucosiltransferasas/análisis , Hexosiltransferasas/análisis , Humanos , Concentración de Iones de Hidrógeno , Lectinas/análisis , Proteínas de la Membrana/análisis , Sorbitol/farmacología , Streptococcus mutans/fisiología , Sacarosa/análogos & derivados , Sacarosa/farmacología , Factores de Tiempo , Tomografía de Coherencia Óptica/métodos , Desmineralización Dental/microbiología , Factores de Virulencia/análisisRESUMEN
AIM: It is well reported in the scientific literature that there is a high level of periodontal disease and lower caries prevalence in Down Syndrome (DS) individuals, when compared with age-matched non DS individuals. This study was conducted to investigate the process of dental caries in DS children. MATERIALS AND METHODS: In this study the following parameters were considered: oral hygiene habits, levels of Streptococcus mutans (SM) and Lactobacillus spp. (LB), Modified Gingival Index (MGI), and Simplified Oral Hygiene Index (OHI-S). A case group with DS children (n=69) and a control group of non DS children (n=69) were formed to perform this study. Dental caries severity was determined using the DMFT index. Samples of non-stimulated saliva were collected to determine the Lactobacillus spp levels. For SM levels, MSB agar plates were used. RESULTS: The findings revealed that the case group attended dental check-ups more frequently, brushed their teeth more times per day, flossed less, and also more frequently had SM levels classified as high count. The MGI was higher and the OHI-S was lower than the control group (p<0.001). CONCLUSION: No significant differences were found between the DMFT indexes of children from the two groups (p=0.345). The logistic regression analysis showed that in the case group, age, MGI, and SM count were positively related to dental caries (p<0.05).
Asunto(s)
Caries Dental/complicaciones , Síndrome de Down/complicaciones , Higiene Bucal , Índice Periodontal , Streptococcus mutans/aislamiento & purificación , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , Niño , Preescolar , Índice CPO , Caries Dental/microbiología , Caries Dental/patología , Femenino , Humanos , Lactante , Lactobacillus/clasificación , Lactobacillus/aislamiento & purificación , Masculino , Análisis por Apareamiento , Valores de Referencia , Factores de Riesgo , Saliva/microbiología , Estadísticas no Paramétricas , Diente PrimarioRESUMEN
Actinobacillus actinomycetemcomitans is capable of colonizing mucosa and dental plaque and plays an important role in periodontal disease in young peoples and adult. Adherence mechanisms on epithelial cells, tooth or oral bacteria and gingival invasion probably are the initial steps in the pathogenesis of gingivitis or periodontitis. In this study, the adherence of A. actinomycetemcomitans on oral epithelial cells following subculturing were examined. The adherence on oral epithelial cells showed high in all the isolates values but with differences among them and at each time of subculturing. The adherence of A. actinomycetemcomitans FDC Y4 was stable in each of the subcultures. However, adhesion values of all the tested isolates were different except for strains #1, #38 and Y4, suggesting a heterogenicity within this microbial group. Morphologic variations were observed in extracellular structures of the A. actinomycetemcomitans tested. The adhesion process on oral epithelial cells of this organism can be influenced by subcultures, but additional studies are necessary to verify the influence of subculturing on adherence or other virulence factors.
Asunto(s)
Aggregatibacter actinomycetemcomitans/ultraestructura , Células Epiteliales/microbiología , Boca/microbiología , Adhesión Bacteriana/fisiología , Humanos , Microscopía Electrónica , Boca/citología , Periodontitis/microbiologíaRESUMEN
The aim of this investigation was to determine whether sublethal concentrations of chlorhexidine (Cx), hexetidine (Hx), cetylpyridinium chloride (Cc), sodium dodecyl sulfate (SDS), sanguinarine (Sg), sodium fluoride (NaF), and ammonium fluoride (NH4F) could affect hydrophobicity and adhesion of Streptococcus sanguis and Streptococcus mutans to saliva-coated hydroxyapatite (S-HA). Determination of the minimum inhibitory concentrations (MICs) showed that both species were susceptible to all agents tested. Growth in the presence of sub-MIC concentrations of Cx, SDS, Cc, NaF, or NH4F did not change significantly the hydrophobicity of S. sanguis cells when compared to the control which lacked any agent. However, growth in the presence of Hx or Sg resulted in a significant reduction in their hydrophobicity. Sub-MIC levels of SDS or Sg in the growth medium resulted in S. mutans cells with increased affinity for hexadecane compared with the control. The adherence of S. sanguis was changed significantly only by Hx or Sg, resulting in less cells adhering to S-HA. However, S. mutans cells previously incubated with NaF, NH4F, or Sg showed a higher adherence to S-HA than the control. The mechanisms of interference with adherence are at present not completely understood. Thus, antimicrobial agents at sub-MIC concentrations can interfere selectively with hydrophobicity and/or adhesion of oral streptococci.
Asunto(s)
Antiinfecciosos Locales/farmacología , Adhesión Bacteriana/efectos de los fármacos , Streptococcus mutans/efectos de los fármacos , Streptococcus sanguis/efectos de los fármacos , Adsorción , Alcaloides/administración & dosificación , Alcaloides/farmacología , Alcanos , Compuestos de Amonio , Antiinfecciosos Locales/administración & dosificación , Benzofenantridinas , Cetilpiridinio/administración & dosificación , Cetilpiridinio/farmacología , Clorhexidina/administración & dosificación , Clorhexidina/farmacología , Placa Dental/microbiología , Durapatita , Fluoruros/administración & dosificación , Fluoruros/farmacología , Hexetidina/administración & dosificación , Hexetidina/farmacología , Humanos , Isoquinolinas , Compuestos de Amonio Cuaternario , Saliva/fisiología , Dodecil Sulfato de Sodio/administración & dosificación , Dodecil Sulfato de Sodio/farmacología , Fluoruro de Sodio/administración & dosificación , Fluoruro de Sodio/farmacología , Streptococcus mutans/crecimiento & desarrollo , Streptococcus mutans/fisiología , Streptococcus sanguis/crecimiento & desarrollo , Streptococcus sanguis/fisiología , Propiedades de Superficie , AguaRESUMEN
The purpose of this study was to evaluate the effect of acid conditioning and occlusal sealant on microbial colonization of pit and fissures submitted to ameloplasty or left intact. Human enamel blocks containing fissures prepared from the occlusal surfaces of unerupted third molars were implanted in occlusal fillings in molars of 12 patients for seven, 30, 60, and 120 days. After seven days of exposure to the oral environment, the pit and fissure blocks were removed and found to be colonized, mainly with gram-positive coccal flora. The acid-etching procedure itself reduced the number of cultivable microorganisms by about 95%. Subsequent application of occlusal sealant caused a gradual decrease of the remaining viable microorganism throughout the experiment. Despite the decrease of 100% after acid etching in most of the fissures submitted to ameloplasty, the occlusal sealant did not lead to a subsequent significant reduction.