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PubMed1993

Effect of milk on cariogenesis.

Sprague-Dawley rats fed diet 2000, infected by Streptococcus sobrinus, and offered milk or lactose-reduced milk as drinking fluids developed essentially similar caries scores as controls given distilled water. In contrast, animals given fructose or sucrose solutions developed enhanced levels of caries. Significant differences were not detected in the S. sobrinus populations among the groups. In further experiments, the addition of sucrose to milk enhanced the severity of caries scores. However, sucrose-milk solutions were significantly less cariogenic than sucrose-water solutions. Animals fed sucrose (2-5%) milk solutions harbored enhanced populations of S. sobrinus. The results, overall, suggest that milk may have modest cariostatic properties when ingested at the same time as a cariogenic challenge.

Animals↗

PubMed2003

Effectiveness of dentine bonding agents against cariogenic bacteria in vitro: a comparison of two methods.

Data obtained from studies on the antimicrobial properties of bonding agents are the subject of controversy, probably because of methodological differences. This study compared two commonly used in vitro methods, the disc agar diffusion test and the well agar diffusion test. Agar plates were seeded with Streptococcus sobrinus, Lactobacillus gasseri, or Actinomyces naeslundii. For the well diffusion test, wells cut out of the agar were filled with the test material, and for the disc method, discs impregnated with the test material were applied to the agar; the discs and wells were both 9 mm in diameter. After incubation, measurements of the zones of inhibition showed little agreement between the two methods when bonding agents were tested; the mean differences (+/- sdiff) in the zones of inhibition between the methods were 0.7 +/- 3.4 mm (P = 0.40, one sample t-test against zero), 4.9 +/- 4.4 mm (P = 0.97), and 0.8 +/- 4.3 mm (P = 0.47) for S. sobrinus, L. gasseri, and A. naeslundii, respectively. Mean differences were less contrasting when chlorhexidine and pure components were tested (P < 0.05 for S. sobrinus and L. gasseri). These results indicate the need for a gold standard method to evaluate the antimicrobial properties of bonding agents.

Actinomyces↗

PubMed1992

Mutans streptococci, lactobacilli and caries prevalence in 15 to 16-year olds in Göteborg. Part II.

During the fall of 1987 one hundred and fifty-five 15 to 16-year-olds were examined with regard to caries prevalence, saliva secretion rate and salivary numbers of mutans streptococci and lactobacilli. In 15% of the subjects no mutans streptococci were detected, while 17.7% carried > 10(6) colony forming units (cfu) per ml saliva. The median value was 1.8 x 10(5) cfu per ml saliva. No lactobacilli were detected in 19% of the subjects and 14.3% had > 10(5) cfu per ml saliva. The mean caries prevalence was 21.0, of these 14.1 were incipient lesions. Increased numbers of mutans streptococci and lactobacilli were associated with increasing caries prevalence. Subjects with high numbers of both microorganisms showed about 4 times higher mean caries prevalence than those with low numbers. Streptococcus sobrinus carriers (15%) had both higher mean caries prevalence and a higher proportion of subjects with > 10(6) cfu mutans streptococci per ml saliva than was found in the whole group.

Adolescent↗

PubMed1998

Effects of various resin composite (co)monomers and extracts on two caries-associated micro-organisms in vitro.

Previous studies have shown that extracts of various filling materials, e.g., resin composites, may influence the growth of cariogenic micro-organisms. The purpose of this study was to examine the effects of important resin composite (co)monomers (Bis-GMA, UDMA, TEGDMA, EGDMA) and extracts of two commercial dental composites with similar composition (composite A, Arabesk; composite S, Superlux) on the growth of the two cariogenic bacterial pathogens Streptococcus sobrinus and Lactobacillus acidophilus. It was found that neither the monomers Bis-GMA and UDMA, nor the comonomer EGDMA, nor the extract of composite A influenced the growth of S. sobrinus in the log phase. The comonomer TEGDMA and the extract of composite S were found to stimulate growth in the log phase, but this stimulation was not statistically significant. However, EGDMA, TEGDMA, and the extract of composite S did stimulate the total growth of S. sobrinus. In the assays with L. acidophilus, Bis-GMA, UDMA, and the extract of composite A inhibited the growth in the log phase, whereas TEGDMA stimulated it. Furthermore, EGDMA, TEGDMA, and the extract of composite S stimulated the biomass production of L. acidophilus. We conclude from our results that a release of EGDMA and TEGDMA from resin composites should be avoided due to their growth-stimulating effects on the caries-associated micro-organisms S. sobrinus and L. acidophilus.

Biomass↗

PubMed1993

Expression and secretion of an Arthrobacter dextranase in the oral bacterium Streptococcus gordonii.

We have constructed a plasmid to express and secrete dextranase in the oral bacterium Streptococcus gordonii. The dextranase gene from Arthrobacter sp. strain CB-8 was linked to a promoter and a DNA sequence encoding the signal peptide of Streptococcus downei glucosyltransferase I (gtfI) followed by the Escherichia coli rrnBt1t2 terminator and inserted in the shuttle vector pVA838. S. gordonii transformed with this plasmid (pMNK-4) expressed and secreted mature Arthrobacter dextranase. The transformant was found to repress the firm adherence of water-insoluble glucan in a coculture experiment with cariogenic bacteria, Streptococcus sobrinus, in the presence of sucrose. Such genetically engineered oral bacteria could provide a therapy to prevent dental caries.

Amino Acid Sequence↗

PubMed1993

Identification of antigenic epitopes in an alanine-rich repeating region of a surface protein antigen of Streptococcus mutants.

A surface protein antigen (PAc) of Streptococcus mutans with a molecular mass of 190 kDa is considered to play an important role in the initial attachment of this streptococcus to the tooth surface. Two internal repeating amino acid sequences are present in the PAc molecule. One repeating region located in the N-terminal region is rich in alanine (A-region), and the other, located in the central region, is rich in proline (P-region). To identify antigenic epitopes on the A-region of the PAc protein, 82 sequential overlapping synthetic decapeptides covering one of the repetitive units of the A-region were synthesized. In the epitope scanning analyses using murine antisera raised against recombinant PAc (rPAc), multiple antigenic epitopes were found in the repetitive unit of the A-region, and some of them reacted with antisera to rPAc from BALB/c, B10, B10.D2, and B10.BR mice. In particular, a peptide YEAALKQY (residues 366 to 373) was recognized by anti-rPAc sera from all four strains of mice. The reactivities of anti-rPAc sera in the epitope scanning were confirmed by using a purified synthetic peptide, NAKATYEAALKQYEADLAA (corresponding to residues 361 to 379). Furthermore, antisera against a surface protein antigen PAg (SpaA) of Streptococcus sobrinus from BALB/c mice reacted strongly to residues 330 to 337, 362 to 369, and 366 to 373 of the PAc protein by the epitope scanning analysis. An AKATYEAALKQY (residues 362 to 373 of the PAc protein)-like sequence, AKANYEAKLAQY, was found within the A-region of S. sobrinus PAg, suggesting that the amino acid sequences AKA-YEA and YEA-L-QY may be major cross-reactive epitopes of the S. mutans PAc protein and the S. sobrinus PAg protein.

Amino Acid Sequence↗

PubMed1991

Influence of milk, lactose-reduced milk, and lactose on caries in desalivated rats.

There is a growing population who suffer from hyposalivation. These patients frequently sip liquids to alleviate their discomfort. Milk appears to have many of the physical properties of a good saliva substitute. Desalivated rats given 2% milk or lactose-reduced milk remained essentially caries-free. In contrast, animals given sucrose or lactose to drink developed caries. In addition, animals given sucrose or lactose harbored significantly higher populations of Streptococcus sobrinus than did other groups. Results showed that milk and lactose-reduced milk can be used safely by hyposalivatory patients as a saliva substitute.

Animals↗

PubMed1993

Identification and characterization of a mobilization gene in the streptococcal plasmid, pVA380-1.

The 4.2-kb cryptic streptococcal plasmid, pVA380-1, has a broad host range and replicates via a rolling circle mode. The nucleotide base sequence of the 2.5-kb basic replicon of this plasmid, containing a plus origin, a minus origin, and a rep gene, was reported previously. The completed nucleotide base sequence of pVA380-1 revealed the presence of two additional open reading frames, ORF2 and ORF3. The protein predicted by ORF2 shared 74% amino acid identity with the Mob protein of the Group B streptococcal plasmid, pMV158. The 170 bases immediately 5' to ORF2 and to mob of pMV158 shared 87% homology and included a putative -10 region and a RSa site. A derivative of pVA380-1 into which a kanamycin resistance gene was inserted outside of the above 170 base region and ORF2 was mobilized by the conjugative streptococcal plasmid, pAM beta 1, into Enterococcus faecalis and Streptococcus sobrinus. Interruption of ORF2 by the same kanamycin resistance gene abolished the mobilizability of pVA380-1.

Amino Acid Sequence↗

PubMedDate not supplied

A method for mapping the distribution pattern of cariogenic streptococci within dental plaque in vivo.

This study was carried out to develop a method for mapping the distribution of cariogenic oral streptococci, Streptococcus mutans and Streptococcus sobrinus, from the outermost to the innermost plaque. Ten consenting subjects were asked to form plaque by abstaining from tooth brushing over 3 days within in situ plaque-generating devices, which were placed on the upper molars. The plaque formed in the devices was separated into 8-10 layered fractions (100 microm thick). Genomic DNA was extracted from each plaque fraction by a commercial DNA purification kit and used for the amplification of the 16S ribosomal RNA gene sequences by polymerase chain reaction (PCR) with universal primers. The products were then amplified by PCR with S. mutans- or S. sobrinus-specific nested primers. The final products were separated on agarose gels, stained and photographed to confirm the existence of S. mutans and S. sobrinus. The results showed that S. mutans was detected in the plaque obtained from all of the 10 subjects and S. sobrinus in the plaque of 7 subjects. However, the distribution patterns of fractions positive for S. mutans and S. sobrinus varied among the subjects, with a tendency for frequent detection of both species in the outer to middle layers of dental plaque. There were no plaque fractions in which only S. sobrinus was found. This method could be useful to map the distribution of cariogenic microorganisms and to estimate the bacterial ecology for oral biofilm.

Adult↗

PubMed2004

Detection of cariogenic bacteria genes by a combination of allele-specific polymerase chain reactions and a novel bioluminescent pyrophosphate assay.

We developed a novel bioluminescent assay for detection of pyrophosphate in polymerase chain reaction (PCR) product. The principle of this method is as follows: pyrophosphate released by PCR is converted to adenosine 5'-triphosphate (ATP) by pyruvate phosphate dikinase in the presence of the substrate pyruvate phosphate and the coenzyme adenosine 5'-monophosphate; subsequently, ATP concentration is determined by firefly luciferase reaction. The detection limit of pyrophosphate is 1.56 x 10(-15)mol/assay. Additionally, luminescent intensity reached a maximum at approximately 100 s and remained elevated beyond 10 min. This approach is applicable to the detection of cariogenic bacteria in dental plaque. Thus, the allele-specific PCR products of Streptococcus mutans and Streptococcus sobrinus developed in this study were measured via the proposed bioluminescent assay. This protocol, which does not require expensive equipment, can be utilized to rapidly monitor cariogenic bacteria in dental plaque.

Alleles↗

PubMed2006

Bacterial profile in primary teeth with necrotic pulp and periapical lesions.

The objective of this study was to evaluate the bacterial profile in root canals of human primary teeth with necrotic pulp and periapical lesions using bacterial culture. A total of 20 primary teeth with necrotic pulp and radiographically visible radiolucent areas in the region of the bone furcation and/or the periapical region were selected. After crown access, 4 sterile absorbent paper points were introduced sequentially into the root canal for collection of material. After 30 s, the paper points were removed and placed in a test tube containing reduced transport fluid (RTF) and were sent for microbiological evaluation. Anaerobic microorganisms were found in 100% of the samples, black-pigmented bacilli in 30%, aerobic microorganisms in 60%, streptococci in 85%, gram-negative aerobic rods in 15% and staphylococci were not quantified. Mutans streptococci were found in 6 root canals (30%), 5 canals with Streptococcus mutans and 1 canal with Streptococcus mutans and Streptococcus sobrinus. It was concluded that in root canals of human primary teeth with necrotic pulp and periapical lesions, the infection is polymicrobial with predominance of anaerobic microorganisms.

Child↗

PubMed1993

Effects of fluoxetine on the oral environment of bulimics.

The purpose of this study was to evaluate in a double-blind placebo-based study the effects of fluoxetine over a period of 16 weeks on the frequency of binging and purging and on fluctuations in the levels of cariogenic organisms and saliva secretion rate of patients (n = 30) with bulima nervosa. Profile analysis suggested that, over the course of the study, binging and purging frequency and Streptococcus sobrinus salivary levels decreased significantly in the fluoxetine group as compared with the placebo group. Our finding that S. sobrinus levels decreased 16 weeks after subjects were on medication suggests that the salivary levels of these organisms could serve as an objectively measured indicator of patient compliance with antibulimic therapy.

Analysis of Variance↗

PubMedDate not supplied

Influence of rampant caries in dams on caries activity in their offspring.

Available evidence indicates that infants, for the most part, acquire their oral flora, in particular Streptococcus mutans, from their mothers. The purpose of this study was to explore the effect of rampant caries in rat dams on subsequent caries activity in their offspring. Rampant caries was induced by surgical desalivation of four dams, and subsequent infection with Streptococcus sobrinus 6715. Two intact dams served as controls. Desalivated dams, having rampant caries, reared litters that experienced significantly higher caries scores (P = 0.0001) on smooth and sulcal surfaces than litters from intact dams. Fluoride given to the dams did not affect caries scores of their pups. The results suggest that the magnitude and virulence of the maternal reservoir of S. sobrinus is a critical factor in the primary infection and caries activity in the offspring. Results support the concept that caries activity in mothers should be controlled in any program designed to prevent caries in infants and children.

Analysis of Variance↗

PubMed2000

Dental caries is a preventable infectious disease.

Dental caries is the most common infectious disease affecting humans. The principal causative agents are a group of streptococcal species collectively referred to as the mutans streptococci of which Streptococcus mutans and Streptococcus sobrinus are the most important agents of human caries. This review outlines what is currently known about these ubiquitous pathogens and discusses novel methods for elimination of these bacteria from dental plaque.

Adult↗

PubMed1995

The action of thymol on oral bacteria.

Several effects of thymol, a plant-derived antimicrobial agent, on Porphyromonas gingivalis, Selenomonas artemidis and Streptococcus sobrinus were examined. The extremely rapid efflux of intracellular constituents evoked by thymol is consistent with its postulated membranotropic effects. Correlations between leakage-inducing concentrations of thymol and minimal inhibitory concentrations and minimal bactericidal concentrations suggest that membrane perforation is a principal mode of action of this substance. The thymol-induced decline in intracellular ATP in S. sobrinus appears to be entirely attributable to leakage, whereas in P. gingivalis thymol may also inhibit ATP-generating pathways. Relative changes in the transmembrane potential of resting cells of S. sobrinus pulsed with glucose are as sensitive to thymol as is leakage from this organism. The effects of thymol on transmembrane potential are probably secondary to those arising from leakage of intracellular substances.

Adenosine Triphosphate↗

PubMed1992

Molecular analysis of a Streptococcus mutans strain exhibiting polymorphism in the tandem gtfB and gtfC genes.

Streptococcus mutans UA101, which was previously demonstrated to be highly cariogenic in gnotobiotic rats, exhibited much lower water-insoluble glucan (IG) synthetic activity compared with that of S. mutans GS5 and was unable to express sucrose-dependent colonization of smooth surfaces in vitro. On the basis of Southern and Western blot (immunoblot) analyses, it was demonstrated that, unlike most S. mutans strains, strain UA101 contained a single copy of a gene coding for IG synthesis. The gene was isolated from a clone bank constructed with the plasmid pTH10 clone bank in Escherichia coli and had apparently evolved after homologous recombination of the gtfB and gtfC genes present on the chromosome of a recent ancestor of strain UA101. The enzyme expressed from the gene, gtfBC, was purified to near homogeneity by utilizing a single-step preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis system and was characterized. A derivative of strain UA101, UA101LBS, containing a chromosomal insertion of the GS5 gtfC gene was constructed after transformation. UA101LBS exhibited high IG synthetic activity and colonized smooth surfaces in vitro. By utilizing a conventional rat model system involving animals fed a high-sucrose diet, strain UA101 exhibited low levels of smooth surface caries activity relative to Streptococcus sobrinus 6715. By contrast, UA101LBS was as cariogenic as strain 6715. However, sulcal caries occurred equally well with all of the strains tested. These results are evaluated relative to the role of gtf gene products in cariogenicity.

Animals↗

PubMed2004

A high molecular mass cranberry constituent reduces mutans streptococci level in saliva and inhibits in vitro adhesion to hydroxyapatite.

Previous investigations showed that a high molecular mass, non-dialyzable material (NDM) from cranberries inhibits the adhesion of a number of bacterial species and prevents the co-aggregation of many oral bacterial pairs. In the present study we determined the effect of mouthwash supplemented with NDM on oral hygiene. Following 6 weeks of daily usage of cranberry-containing mouthwash by an experimental group (n = 29), we found that salivary mutans streptococci count as well as the total bacterial count were reduced significantly (ANOVA, P < 0.01) compared with those of the control (n = 30) using placebo mouthwash. No change in the plaque and gingival indices was observed. In vitro, the cranberry constituent inhibited the adhesion of Streptococcus sobrinus to saliva-coated hydroxyapatite. The data suggest that the ability to reduce mutans streptococci counts in vivo is due to the anti-adhesion activity of the cranberry constituent.

Adult↗

PubMed1994

Immunoglobulin A antibodies to mutans streptococci in human saliva and serum comparing fresh and subcultivated strains and activity in repeated saliva samples.

The aims of this study were i) to characterize and compare the sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein patterns of reference Streptococcus mutans and Streptococcus sobrinus strains, subcultivated for years, with fresh isolates of the same serotype; ii) to study possible differences between the human salivary immunoglobulin A (IgA) activity to reference strains and to fresh bacterial isolates of the saliva donors; iii) to examine for potential differences in the salivary IgA activity to the streptococcal antigens during 1 week; and iv) to map, in the same individuals, the serum IgA activity against the selected bacteria. S. mutans reference and fresh isolated strains showed a similar protein pattern with few exceptions. The immunoblot also revealed similarity in saliva IgA response, with only one subject's saliva displaying clearly one band's difference. For S. sobrinus a larger discrepancy was seen. The antibody activity during the one week interval was essentially unchanged. When incubated with serum, a different immunoblot profile was seen compared with saliva, although most bands revealed by saliva were also displayed by serum.

Adult↗