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PubMed1990

The effects of sucralose on coronal and root-surface caries.

Sucralose is an intensely sweet, chlorinated carbohydrate structurally similar to sucrose; thus, its cariogenic potential is of great interest. Four groups of 12 Sprague-Dawley rats were infected with Streptococcus mutans (sobrinus), caged in a König-Höfer programmed feeding machine, and fed diet 2000 or modified diet to contain sucralose at various concentrations instead of sucrose. Rats fed sucralose diet developed significantly fewer lesions than did the rats fed regular diet 2000. Animals fed diet 2000 also harbored more S. mutans (sobrinus) than did the other groups of animals. In a concurrent study, desalivated rats were inoculated with S. mutans (sobrinus) and Actinomyces viscosus. They were fed (ad libitum) either diet 2000 (contains 56% sucrose) or diet 2000 minus sucrose plus 93 mg% sucralose. The severity of caries lesions in the sucralose-fed rats after 35 days was significantly less than those in the sucrose-fed rats. The amount of root exposure was the same in both groups. However, root-surface caries did not develop in the sucralose-fed rats. These results show that sucralose is non-cariogenic in rats.

Actinomyces↗
PubMed1993

Protective effect of topically applied fluoride in relation to fluoride sensitivity of mutans streptococci.

The aim of the present in vitro experiments was to determine whether the protection of enamel by topically applied fluoride against demineralization by bacterial acids would depend on the fluoride sensitivity of the bacteria. Glucose-agarose gel suspensions of fluoride-sensitive and fluoride-resistant mutans streptococci were placed on bovine enamel specimens with different amounts of fluoride. One group of specimens was untreated, a second group had been pretreated with a F-lacquer, and a third group had been pretreated with the F-lacquer and rinsed subsequently with a KOH-solution, to remove deposited CaF2. After 22-hour incubations at 37 degrees C, the amounts of calcium and lactate and the pH of the agarose gels were determined. This procedure was repeated on three consecutive days. Two parent S. mutans strains, one parent S. sobrinus strain, and five fluoride-resistant derivatives were tested. Both pretreatments gave a significant protection to the enamel specimens. For the S. mutans strains, the degree of protection did not depend on the fluoride sensitivity of the strains. For the S. sobrinus strains, the results suggested a reduced protection against demineralization by the fluoride-resistant derivatives. Only from the second group of enamel specimens was enough fluoride released for inhibition of bacterial metabolism. Presumably, it was released by the dissolution of CaF2. It is concluded that a possible adaptation of mutans streptococci in dental plaque to frequent exposures to fluoride will not necessarily decrease the caries-preventive effects caused by topically applied fluoride agents.

Adaptation, Biological↗
PubMed1992

Effect of gels containing stannous fluoride on oral bacteria--an in vitro study.

The purposes of this investigation were to evaluate and compare the antimicrobial effect of (1) twelve 0.4 per cent stannous fluoride (SnF2) commercial products and (2) different concentrations of SnF2 (range = 0.02 to 3.28 per cent). The antibacterial inhibitory effect of various SnF2 gels was evaluated as to their effectiveness against oral plaque bacteria including strains of S. mutans, S. sanguis, S. sobrinus, A. viscosus, A. actinomycetemcomitans, and B. intermedius. When twelve different commercial preparations of 0.4 per cent SnF2 were compared for inhibitory effect on plaque bacteria, several of the SnF2 preparations were significantly more effective in inhibiting oral bacteria (p < 0.05). With increasing concentration of SnF2, there was a comparable increase in the inhibitory effect on the oral bacteria tested (r2 ranged from 0.867 to 0.996). SnF2 at a concentration of 0.4 per cent had a similar antibacterial effect to 0.12 per cent chlorhexidine. This in vitro study demonstrated that certain SnF2 products are highly effective in inhibiting the growth of bacteria often found in plaque, and this inhibitory effect is directly related to the concentration of the SnF2.

Actinomyces viscosus↗
PubMed1988

Sulcal plaque pH and remineralization of sulcal caries in rats exposed to dietary and water fluoride.

After being inoculated with Streptococcus (mutans) sobrinus 6715 and fed a mildly caries-promoting diet for 14 days, sulcal plaque pH response to topical application of a 10% sucrose solution was measured in two groups of rats. The first group (experimental) was then fed diet and drinking water to which 1 mmol (20 ppm) fluoride had been added (0.5 mmol for 7 days and 1 mmol for 14 days) and pH measurements were repeated. The second group was held as a control and a third group was sacrificed to provide baseline caries scores. There was no difference in the fall in pH after topical application of 10% sucrose solution between the control and experimental group, nor between the pre- and postfluoride measurements for the experimental group. Sulcal caries incidence in the experimental group was significantly lower than in the control group. The results of this experiment emphasize the importance of a cariostatic mechanism of action for fluoride based on remineralization of enamel lesions and do not support the in vivo adaptation to fluoride by oral microorganisms.

Animals↗
PubMed2006

The in vitro effect of fluoridated milk in a bacterial biofilm--enamel model.

OBJECTIVES: The purpose of this study was to investigate the effect of milk and fluoridated milk on bacterially induced caries-like lesions. SAMPLE AND METHODS: Extracted impacted human molars were cut in half and covered with a varnish leaving a 4*4 mm window. The samples were coated with biofilm of S. sobrinus and were further divided into three experimental groups of S. sobrinus, S. sobrinus and milk and S. sobrinus and fluoridated milk. As negative controls served teeth incubated in saline. Of twenty tooth halves serial ground sections were cut through the lesions and investigated with polarization light microscopy (PLM) and scanning electron microscopy (SEM) and EDX element analysis. The PLM photographs were used for 3D reconstruction, volumetric assessment and determination of the extension of the lesion zones. Of eight tooth halves the biofilm on the enamel surface was studied with SEM and EDX element analysis. RESULTS: Volumetric assessment showed a statistically significant difference in the volume of the body of the lesion and the translucent zone between the milk group and fluoridated milk group. Quantitative element analysis demonstrated significant differences between sound enamel and the superficial layer in the fluoridated milk group. The biofilm on the enamel surface showed an increased Ca content in the milk group and fluoridated milk group. CONCLUSIONS: Milk as a common nutrient seems to play a complex role in in-vitro biofilm--enamel interactions stimulating bacterial demineralization on one hand, and, as effective fluoride carrier, inhibits caries-like demineralization.

Animals↗
PubMed1995

Comparison of cell sediment and surface grown "test plaque" using scanning electron microscopy.

Scanning electron microscopy was used to compare the morphology, integrity and distribution of bacterial cells in a test plaque grown on the surface of enamel with that of the cell sediment plaque routinely used in a short-term intraoral caries model. Cultures of S. mutans IB-1600 or S. sobrinus 6715-13 were grown in complex media supplemented with either 2.0% sucrose (glucan plaque) or 0.2% glucose (non-glucan plaque). Cell sediment (CS) plaque was prepared by centrifuging the cultures after incubation, recovering the cell sediment, and spreading it on Metricel membrane filter paper. Surface grown (SG) plaque was prepared by suspending saliva-coated bovine enamel in the culture medium, incubating, and recovering the enamel assembly with bacterial accumulations. Cell morphology and integrity, as well as the appearance of glucan-like material produced by the cells, was similar in both CS and SG test plaques. The cell distribution however, varied in the SG plaque from extremes of all cells to all glucan, whereas the cell sediment plaque was more uniform in cell distribution. A highly standardized test plaque minimizes variability in the intraoral caries model. These findings support the contention that the bacterial cells in a cell sediment plaque are similar in morphology, integrity and glucan production to surface grown plaque, and have the added advantage of uniform distribution, which makes the cell sediment plaque more appropriate for intraoral caries model studies.

Animals↗
PubMed1996

Cariogenicity depends more on diet than the prevailing mutans streptococcal species.

This review aims to compare the occurrence and distribution of mutans streptococci in Africa, Europe, and North America and in addition will try to offer explanations for existing relationships among salivary mutans streptococci counts, dietary patterns, and dental caries. The literature reveals that salivary mutans streptococci counts in child populations of the three continents are comparable. The distribution of mutans streptococci species, with a predominance of S. mutans followed by S. sobrinus, and the virtual absence of other mutans streptococci species are also comparable. Although it is widely believed that diet has an important effect on mutans streptococci counts, this review provides evidence that this does not hold true when variations in dietary patterns are moderate, as they normally are in real-life situations. Since the diets of the child populations in the three continents vary moderately, a strong dietary-induced effect on salivary mutans streptococci counts cannot be expected. The observed analogous salivary mutans streptococci counts in these child populations are thus 'not surprising' but are in accordance with the conceptual expectation. The differences in caries experience in children of the three continents cannot be explained by the prevailing mutans streptococci species but instead should be attributed to differences in the cariogenicity of the various diets. The fact that the cariogenicity of the diet determines the development of dental caries while hardly affecting the mutans streptococci counts explains the limited value of the latter as an indicator of dental caries. The reviewed literature shows that mutans streptococci are ubiquitous in children aged 7 years and older in Africa, Europe, and North America. Mutans streptococci should therefore be considered as belonging to the indigenous microflora of the human mouth.

Adolescent↗
PubMed2000

Effects of three different infant dentifrices on biofilms and oral microorganisms.

The purpose of this work was to evaluate the effects of infant dentifrices: A--with lactoperoxidase, glucose oxidase and lactoferrin; B--with 1100 ppm of NaF and sodium lauryl sulfate; C--with extract of calendula. The dentifrices were test on biofilms formed in vitro from saliva and dental plaque of infants, using reference strains A. viscosus (ATCC 43146); C. albicans (ATCC 51501); L. casei (ATCC 4646); S. mitis (ATCC 49456); S. mutans (ATCC 25175); S. oralis (ATCC 35037); S. sanguis (ATCC 10586); S. sobrinus (ATCC 27609) and isolated clinically microorganisms C. albicans, S. mitis, S. mutans, S. oralis, S. sanguis, S. sobrinus and Lactobacillus sp. Twenty infants were chosen, who were beginning treatment at the Infants Clinic of the Pediatric Dentistry Department, Federal University of Rio de Janeiro. A pool of unstimulated saliva and a pool of dental plaque were collected from which biofilms were produced. Supernatants from each dentifrice were prepared and concentrated and diluted solutions of the dentifrices and a control sterile diluent were tested against the biofilms produced, for 1 and 3 minutes, and against the microorganisms. The results were statistically analyzed by the ANOVA and Tukey Test. After the exposure of the biofilms produced both from saliva and from dental plaque, to the dentifrice B concentrated and 1/2, for 1 and 3 minutes, the viable microorganisms count (CFU/ml), compared to the controls, was significantly reduced (p < 0.05). However, exposure to the dentifrices A and C concentrated and dentifrice B 1/4 and 1/8, for 1 and 3 minutes, was not significantly lethal to the biofilms. The dentifrices A and C, either concentrated or diluted (1/2 to 1/128) and the dentifrice B in the dilutions 1/16 to 1/128 did not have an antimicrobial effect on any microorganism evaluated. For all the microorganisms evaluated, the dentifrice B concentrated and in the 1/2 dilution showed a significant antimicrobial effect, when compared with the control (p < 0.05).

Actinomyces viscosus↗
PubMed1999

Insoluble glucans synthesized by cariogenic streptococci: a structural study.

Of the three cariogenic streptococci grown in four various culture media, the strain Streptococcus mutans 20,381 was found to produce large amounts of extracellular glucosyltransferase and water-insoluble, adhesive exopolysaccharide when grown in batch culture on brain-heart infusion broth. Methylation and nuclear magnetic resonance analyses revealed that the insoluble polymers synthesized by the crude glucosyltransferase preparations were mixed-linkage (1-->3), (1-->6)-alpha-D-glucans (so-called mutans) with a greater proportion of 1,3 to 1,6 linkages and major branch points of 3,6-linked glucose. The percentage content of different types of linkages in glucans varied widely and depended on the strain of cariogenic bacteria used to produce glucosyltransferase, and on the kind of medium utilized to cultivate mutans streptococci. The potential application of insoluble glucan produced by mutans streptococci is discussed.

Culture Media↗
PubMed1993

Grouping of oral streptococcal species using Fourier-transform infrared spectroscopy in comparison with classical microbiological identification.

The grouping and identification made by Fourier-transform infrared spectroscopy (FT-IR) of 40 oral streptococcal strains was compared with their known taxonomic positions. Grouping was obtained by cluster analysis on the spectral distances between the first derivative spectra of the strains. Spectra were divided into five spectral 'windows' and cluster analysis was either on either a combination of all five windows or on a selected window. The oral streptococci were divided into two main clusters, mutans streptococci and other streptococci. This division was based mainly on the spectral information contained in the window between 1300-900 cm-1, indicative of polysaccharide and phosphate-carrying compounds. In the grouping based on the entire spectrum, species clusters could be observed for Streptococcus crista, Strep. salivarius and Strep. rattus. A few strains were placed in wrong clusters because of intra-strain variance. It is concluded that the grouping of these oral streptococcal species was good and similar to the classical taxonomy and that FT-IR might develop into a new identification method for oral streptococci.

Animals↗
PubMed1994

Influence of caries-preventive measures in mothers on cariogenic bacteria and caries experience in their children.

Preventive measures, which reduced the salivary level of mutans streptococci in mothers, delayed colonization by these organisms in their children. The preventive programme was discontinued when the children were 3 years old. These children, at the age of 7 years, and their mothers were now examined to determine the effect of the earlier caries-preventive approach. The control mothers had significantly higher levels of salivary mutans streptococci and lactobacilli than the test mothers (p < 0.05). The median level of salivary mutans streptococci was 0.6 x 10(6) c.f.u. (colony-forming units) per ml in the test mothers and 1.3 x 10(6) c.f.u. in the control mothers. The median level of salivary lactobacilli was 10 times higher in control than test mothers (80 x 10(3) and 7 x 10(3) c.f.u. per ml, respectively). Significantly more children of control than test mothers carried mutans streptococci (95 versus 46%) (z-test; p < 0.01). Children of test mothers had lower salivary levels of mutants streptococci and lactobacilli (p < 0.05). Twenty three % of the test children were caries-free, compared with 9% of the control children (z-test; p < 0.01). The mean caries experience of the test children was also significantly lower than that of the control children (defstot 5.2 and 8.6, respectively; p < 0.05). The results show that reduction of the mutans streptococci in the mother during the emergence of the primary teeth in her child has a long-term influence on colonization by these bacteria and the caries experience in the child.

Case-Control Studies↗
PubMed1992

Sodium hypochlorite disinfection of irreversible hydrocolloid impression material.

Alginate impression material is one of the most frequently used in dentistry. However, this material is susceptible to dimensional distortion during disinfection because of its hydrophilic nature. This study examined the effects of alginate disinfection using a sodium hypochlorite spray or impression immersion. Spray disinfection of an alginate impression did not cause dimensional differences of the poured stone casts when compared with casts from water-rinsed controls. Immersion disinfection created dimensional distortion of the anterior, posterior, and interarch model segments. Both the spray and immersion treatments equally decreased the surface detail reproducibility. The antimicrobial effects of the spray treatment were similar to those of the immersion treatment, while mere water rinsing resulted in inadequate disinfection.

Aerosols↗
PubMed1993

A simple method for monitoring mutans streptococci in margins of restorations.

Plaque material collected from margins of restorations using a sharp toothpick was streaked across one and the same plastic strip from a commercially available test kit and inoculated in a liquid medium containing bacitracin. The reproducibility of the method was good. The method is simple, inexpensive and suitable for the chairside demonstration of the colonization of mutans streptococci in localized areas of the mouth, such as margins of restorations.

Adult↗
PubMed2006

The effect of traditional African food mixtures on growth, pH and extracellular polysaccharide production by mutans streptococci in vitro.

Four, traditional African food mixtures (maize plus milk and sugar, maize plus gravy, samp plus beans, brown bread plus margarine and peanut butter) were evaluated for their ability to sustain the growth of mutans streptococci in batch culture. A synthetic complex medium, brain heart infusion with 3% sucrose was used as an experimental control. Six NCTC laboratory reference strains and five clinical isolates collected from the plaque of children were investigated. The doubling time of bacterial strains was prolonged in maize plus gravy (2.5-6.0 h) and samp plus beans (1.3-9.9h), and the number of cell divisions was low, compared with bread plus margarine plus peanut butter (0.7-5.1h). The least amount of acid was produced in maize plus milk plus sugar (3.92+/-8.15 mmole/mL), and the average pH during the fermentation of maize plus milk plus sugar, maize plus gravy and samp plus beans did not drop below the critical point for enamel demineralisation, pH 5.7. Bacterial growth in samp plus beans produced a small quantity of lactic acid (0.46+/-1.10 mmole/mL) compared to bread plus margarine and peanut butter (2.64+/-3.30 mmole/mL) and BHI plus 3% sucrose (12.23+/-10.72 mmole/mL). Extracellular polysaccharide (ECP) produced was lowest in maize plus milk and sugar (0.22+/-0.33 mg/mL), compared with the remaining food mixtures (0.47-1.75 mg/mL). Statistical analysis showed that the influence of the mixed-foods on doubling time (F=3.01, P=0.03), pH (F=14.41, P<0.0001) and ECP (F=135.32, P<0.0001) was greater than the significant variance found between mutans streptococci strains. Results suggest that the level of mutans streptococci activity in samp plus beans, maize plus milk and sugar and maize plus gravy contributes little towards the formation of dental caries, and that significant differences exist between mutans streptococci laboratory reference and clinical strains in response to traditional African food mixtures.

Acetic Acid↗
PubMed2006

Presence of mutans streptococci and Candida spp. in dental plaque/dentine of carious teeth and early childhood caries.

This study determined the presence of mutans streptococci and Candida spp. in supragingival dental plaque and infected dentine of caries-free children, with early childhood caries and caries. Pooled samples of dental plaque and infected dentine were collected from 56 children aged 1-5 years, which were divided into 3 groups: early childhood caries (ECC); caries and caries-free. Infected dentine was collected in ECC and caries groups to compare the frequency of these microorganisms in the collected sites. The samples were inoculated in SB20 and SA medium, for mutans streptococci and Candida spp., respectively, and incubated at 37 degrees C for 48 h. Colony growth was verified and the identification was performed by biochemical tests and CHROMagar Candida. Fisher's test or chi-square (chi(2)) were applied (p=0.05). The more prevalent species were S. mutans and Candida albicans in ECC (85.4% and 60.4%, respectively), independently of the sample site. S. mutans only was significantly associated with carious teeth, whether in early childhood caries or not. However, the frequency of C. albicans in ECC was higher when compared to caries and caries-free groups. There is a significant association between the presence of C. albicans and early childhood caries.

Candida↗
PubMed2006

Salivary mutans streptococci counts as indicators in caries risk assessment in 6-7-year-old Chinese children.

OBJECTIVES: This study aimed to determine whether salivary mutans streptococci (MS) counts in Chinese children had any value in the prediction of new caries in the permanent dentition in the age interval of 6.5-8.5 years. METHODS: Four hundred and thirty-three 6-7-year-old children participated in this 2-year longitudinal study. Salivary MS counts were obtained at baseline with the spatula method. Dentin and enamel caries was recorded at baseline and at the follow-up, 2 years later. Spearman's correlation coefficients were computed. Past caries experience variables at baseline were entered into a multiple regression model with caries increment of the permanent dentition as dependent variable. MS counts were subsequently entered into the model to assess the additional caries predictive value. RESULTS: Spearman's correlation coefficient for MS counts and caries experience of the primary dentition at baseline was 0.48 and for MS counts and caries increment in the permanent dentition 0.12. In the multiple regression model caries increment of the permanent dentition had an adjusted R2 of 0.17 when the past caries experience variables were entered. Adding MS counts in the regression model did not change the R2 value. CONCLUSIONS: Salivary MS counts did not add any caries predictive value when past caries experience variables were used as caries predictors in this Chinese child population.

Child↗
PubMed1997

Adherence of oral streptococci to an immobilized antimicrobial agent.

An antimicrobial agent, 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride, was immobilized on silica. Interaction between the material (termed) OAIS) and various oral bacterial species were then studied. Seven species of Streptococcus and two Actinomyces were investigated for their ability to adhere to this biomaterial. Cell-surface hydrophobicity and zeta-potential were examined as well. Analysis of extracted hydrophobic proteins which adhered to OAIS revealed that the adherence of these micro-organisms was closely related to the hydrophobicity of their cell surfaces. The results of zeta-potential assays indicated that negative charge on the cell surface inhibited adherence to OAIS. Gel electrophoresis revealed that OAIS could absorb cell-surface hydrophobic proteins from all bacterial species tested. Preadsorption of hydrophobic components on the cell surface inhibited adherence of the Strep. mutans strain to OAIS in a dose-dependent manner. The results indicate that OAIS adsorption of these oral bacteria was dependent on the degree of hydrophobicity of their surfaces. A major component of this adherence was hydrophobic cell-surface proteins.

Absorption↗