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PubMed1991

Microbiological and immunological aspects of experimental periodontal disease in rats: a review article.

Animal models in which microbiological and immunological aspects of periodontal disease can be studied prospectively seem well warranted. The rat bears much resemblance to man with respect to periodontal anatomy, development and composition of dental plaque, histopathology of periodontal lesions, and basic immunobiology. Furthermore, reproducible methods are available for assessment of periodontal disease in rats, and detectable periodontal destruction can be induced in a few weeks in these animals without traumatizing periodontal tissues with ligatures. Experimental periodontitis studies in germ-free rats have confirmed the pathogenicity of several suspected periodontal pathogens (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Capnocytophaga sputigena, Eikenella corrodens, and Fusobacterium nucleatum). The studies also suggest that the number of periodontal pathogens may be higher than generally believed, since species like Streptococcus sobrinus and Actinomyces viscosus are associated with periodontal bone loss in rats. Studies in rats with congenital or induced immune defects indicate that generalized or selective immunosuppression at the time of infection with periodontal pathogens may aggravate periodontal disease. Studies in immunized rats indicate that periodontal disease can be prevented by immunization against periodontal pathogens. However, it is also possible by immunization to induce periodontal destruction; i.e., the immune system has a destructive potential which should not be overlooked. In the future, the rat model may prove valuable for initial screening of antigen preparations and immunization regimens in the search for a periodontitis vaccine.

Animals↗

PubMed1996

Effect of low-dose glucocorticoid treatment on dentin formation and dentinal caries in rats.

The effect of a low dose of glucocorticoids on dentin formation and progression of dental caries was studied in young rats. The animals were inoculated in the mouth with Streptococcus sobrinus and fed ad libitum a high-sucrose, a high-starch, or a reference diet. The cortisone or placebo pellet was implanted subcutaneously in the back of the necks of the animals. After a 6-week experimental period the areas of dentin formation and dentinal caries were quantified planimetrically. Schiff's staining was used to classify caries. Cortisone reduced the dentin formation both in high-starch and reference diets, but it did not further affect the reducing effect of the high-sucrose diet on dentin formation. Cortisone did not affect the number or severity of dentinal carious lesions.

Analysis of Variance↗

PubMedDate not supplied

Investigation of the role of human breast milk in caries development.

PURPOSE: The objective of this study was to determine the caries-related risk associated with human breast milk (HBM). METHODS: First, the plaque pH of 18 children (12-24 months) was monitored before and after a five-minute feeding with HBM to determine the pH drop and minimum pH obtained. Second, Streptococcus sobrinus 6715 was cultured for 3 hr in HBM, and the increase in the number of colony forming units (cfus) and the culture pH was measured. Third, HBM was incubated for 24 hr with powdered enamel to determine the solubility of mineral in the absence of bacteria. Fourth, HBM was mixed with acid to determine the buffering capabilities. Finally, enamel windows were created on extracted premolar crowns (N = 33) that were colonized with Mutans Streptococci and incubated with HBM. Caries was assessed visually and radiographically for 12 weeks. RESULTS: One- and two-way ANOVAs of these five assays demonstrated that HBM did not cause a significant drop in plaque pH when compared to rinsing with water; HBM supported moderate bacterial growth; calcium and phosphate were actually deposited onto enamel powder after incubation with HBM; the buffer capacity of HBM was very poor; and HBM alone did not cause enamel decalcification even after 12 weeks exposure. However, when supplemented with 10% sucrose, HBM caused dentinal caries in 3.2 weeks. CONCLUSION: It is concluded that human breast milk is not cariogenic.

Analysis of Variance↗

PubMed1992

Odontoblast-mediated regulation of the progression of dentinal caries.

Osteoblasts and odontoblasts are both derived from the same mesenchymal cell line. Our aim was to investigate whether the processes of bone destruction and dentinal caries are biologically similar. The working hypothesis was that after the initiation of caries in the enamel, its rate of progression in the dentine is regulated by cell-mediated factors. Experimental caries was induced in the rat with a high sucrose diet combined with Streptococcus sobrinus infection. Both destruction of dentine and its apposition in the pulp under the carious lesions were measured after vital staining with tetracycline. Caries progression and dentine apposition were higher in developing teeth prior to apex "closure" than in adult, fully-formed teeth. Rats placed on a cariogenic diet during tooth development had an increased rate of caries progression. Fluoride administration via the drinking water was associated with decreased dentine apposition and little progression of dentine caries during the developmental stages. Dentine apposition was enhanced in adult rats placed on fluoride administration, while caries progression was reduced, whereas in animals subjected to metabolic acidosis dentine caries progression was enhanced, with reduced dentine apposition. In contrast, alkalotic animals had less dentinal lesions and smaller ones than the controls. Three theories are advanced to explain the observed changes: (i) They may be associated with changes in alkaline phosphatase activity in the pulpo-dentinal complex, (ii) they may be mediated by ionic changes in the dentinal fluid, or (iii) they may reflect the liberation of growth factors from dentinal matrix.

Acidosis↗

PubMed1995

[Inhibitory effect of green tea polyphenols varnish on oral main cariogenic bacteria.].

This study observed the bacteriostatic effect of green tea polyphenols varnish,found green tea polyphenols varnish had significant inhibitory action on Streptococcus mutans,Streptococcus sobrinus and Lactobacilli.growth test showed the growth inhibitory rate of S.mutans and S.sobrinus was positive proportion with the concentration of green tea polyphenols varnish,demonstrated green tea polyphenols varnish possess certain anticariogenic effect.

English Abstract↗

PubMed1991

Inhibitory effect of stannous fluoride and other commonly used antimicrobial agents on oral bacteria.

The purposes of this investigation were to evaluate and compare the antimicrobial effect of stannous fluoride (SnF2) gel and other commonly used oral antimicrobial agents/products. The antibacterial inhibitory effect of the various agents was evaluated by their effect against oral plaque bacteria including strains of Streptococcus sanguis, Streptococcus sobrinus, Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius. A lawn of the specific bacteria to be tested was placed onto blood agar plates. Wells were then punched into the agar and each well was filled with 75 microliters of one of the antimicrobial products or control solutions. A positive control was a 0.12% chlorhexidine solution and a negative control was physiological saline. Agar plates were incubated in an anaerobic chamber at 37 degrees C for 5-7 days. Zones of inhibition in the lawn of bacteria were measured by a boley gauge. Each experiment was performed in duplicate and mean zones of bacterial inhibition were determined. Only 0.4% SnF2 and 0.12% chlorhexidine were consistently more effective in inhibiting oral bacteria when compared with other commercial mouth rinses/agents which had any one of a variety of antimicrobial agents as ingredients (alpha = 0.05). This in vitro study demonstrates that stannous fluoride gel is as effective as chlorhexidine in inhibiting the growth of bacteria often found in dental plaque.

Anti-Bacterial Agents↗

PubMed1995

[Adherent mechanism of the mutans of Actinomyces viscosus T14V].

Three mutans of Actionmyces viscous T14V lacking type1 (5951), type 2 (5519) and both types of fimbriae (147) were selected in this study. We compared the ability of their adsorption to the test-tube wall, the result of the cellular coaggregation between these mutant strains and Streptococcus sanguis 34, Streptococcus sanguis black bova, Streptococcus mutans ingbritte, Streptococcus sobrinus 6715 and analysed the chemical characterization of cell walls of the three mutans. We found that the specific fimbriae and cell hydrophobicities had great effect on the bacteria adsorption or coaggregation.

Actinomyces viscosus↗

PubMed2002

PCR detection of Streptococcus mutans and S. sobrinus in dental plaque samples from Japanese pre-school children.

Streptococcus mutans and S. sobrinus are associated with the development of dental caries. These bacteria were detected by PCR and then their presence was compared with the incidence of dental caries in 77 Japanese pre-school children. Plaque samples were collected from all erupted tooth sites in the subjects, aged 3-5 years old and each with primary dentition, with a sterile toothbrush. A dental examination was performed for dmft (decayed, missing, filled, total) with the WHO caries diagnostic criteria. In all subjects, the prevalence of S. mutans and S. sobrinus was 72.8% and 61.1%, respectively; 19 (24.7%) were positive for S. mutans alone, 10 (13.0%) were positive for S. sobrinus alone, 37 (48.1%) were positive for both S. mutans and S. sobrinus, and 11 (14.3%) were negative for both S. mutans and S. sobrinus. The dmft scores of children positive for both S. mutans and S. sobrinus were significantly higher than those positive for S. mutans alone. These results indicate that children harbouring both S. mutans and S. sobrinus have a significantly higher incidence of dental caries than those with S. mutans alone.

Age Distribution↗

PubMedDate not supplied

A new selective medium for Streptococcus mutans and the distribution of S. mutans and S. sobrinus and their serotypes in dental plaque.

A new selective medium (MS-MUT) was developed for the isolation of Streptococcus mutans from clinical specimens. The average growth recovery of S. mutans on MS-MUT medium was 72.4% of that on MS medium. Growth of Streptococcus sobrinus was significantly inhibited on the medium with an average recovery of 0.034%. In 103 subjects, S. MUTANS was detected at 58.3, 75.0 and 95.7% in the dental plaque of caries-free (CF), caries-inactive (CI) and caries-active (CA) subjects, respectively. S. sobrinus was detected in 8.3, 13.6 and 38.3% of CF, CI and CA subjects, respectively. S. sobrinus alone was detected in only 4.3% of CA subjects. The subjects in whom neither S. mutans nor S. sobrinus were detected were 41.6% in CF and 25.0% in CI. The most predominant serotype was C with a 67% detection rate. S. sobrinus, serotypes D or G were usually found together with S. mutans.

Adolescent↗

PubMed1995

Mutans streptococci, lactobacilli and caries experience in 12-year-old Icelandic urban children, 1984 and 1991.

In order to evaluate changes in salivary counts of cariogenic bacteria and relate these to trends in caries experience, stimulated saliva was collected from a 20% random sample of 12-yr-old residents of Reykjavik, Iceland (252 children) in 1991 under conditions consistent with those of a survey conducted in 1984. The mean and median counts of salivary mutans streptococci and lactobacilli remained similar in the two studies. However, the frequency distribution at lower levels of mutans streptococci differed significantly between 1991 and 1984, e.g. in the present study 25.8% of the children had < 10(5) compared with 13.8% in the study 1984. The mean caries prevalence in the permanent dentition (DFStot) was 11.0, which is significantly lower than in 1984 (mean DFStot 28.8). A significant difference in caries prevalence was found at various levels of salivary mutans streptococci. Strep. mutans (serotype c/e/f) was carried by all mutans streptococci-positive children, save one child, who carried only Strep. sobrinus. The proportion of 12-yr-olds who carried Strep. sobrinus had decreased significantly to 15.7% from 34.0% in 1984. Significantly more children with Strep. sobrinus showed high levels of total mutans streptococci than children with only Strep. mutans. As the case was in 1984 significantly more Strep. sobrinus carriers had a high level of salivary lactobacilli as well as higher caries prevalence than the children who did not carry this species.

Child↗

PubMedDate not supplied

Growth inhibition of glass ionomer cements on mutans streptococci.

This study was conducted to identify the factors involved in the antibacterial activity of glass ionomer cement (GIC) on mutans streptococci. The antibacterial effect of GIC was estimated using agar plates infected with strains of S. mutans and S. sobrinus. The effect of pH and fluoride release of GIC on mutans streptococci was studied under acid and neutral pH. Strains of S. sobrinus were more sensitive to GIC antibacterial activity, the difference being statistically significant (P < 0.001). The GIC Fuji II LC, Fuji II type II, Vitremer, Vitrebond, and Ketac-Cem were the most active materials in this study. The inhibition activity was associated with GIC fluoride release; 140 +/- 25 ppm were required to inhibit S. sobrinus 6715. Inhibition activity was not associated with changes in pH after setting of these materials.

Anti-Bacterial Agents↗

PubMed1998

Comparison of the cariostatic effects between regimens to administer oolong tea polyphenols in SPF rats.

The cariostatic effect of oolong tea polyphenols administered according to several regimens was examined in specific pathogen-free (SPF) Sprague-Dawley rats given both a diet containing 20% sucrose and infected with S. sobrinus 6715. The crude preparation (OTE) of oolong tea polyphenols showed the most prominent effect on caries reduction in SPF rats when OTE was administered in the drinking water beginning 1 day prior to the inoculation of S. sobrinus 6715, when compared with chromatographically isolated polyphenol fractions (OTF1 and OTF6) of OTE. Reduction in caries development was found even when OTE was given 1 day after inoculation of the organism. OTE was shown to significantly inhibit dental caries in rats at the concentrations of either more than 5 microg/ml in drinking water or more than 10 microg/g in diet. OTF1 and OTF6 also showed significant inhibition of caries induction, with the minimum inhibitory concentration of OTF6 being 50 microg/ml in drinking water and the minimum inhibitory concentration of OTF1 being 100 microg/g in diet. These results indicate that cariostatic activity of OTE was effective even after the establishment of S. sobrinus in the oral cavity and was more effective in drinking water than in diet. Furthermore, OTE may contain some anticaries substances that affect the virulence of S. sobrinus other than glucosyltransferases.

Analysis of Variance↗

PubMed1998

Combined inhibitory effect of bovine immune whey and peroxidase-generated hypothiocyanite against glucose uptake by Streptococcus mutans.

Immune whey product was obtained from Streptococcus mutans- and Streptococcus sobrinus-immunized cows. Hypothiocyanite (HOSCN/OSCN-) was generated in VMG-buffer, pH 5.5 or 6.5, by bovine milk lactoperoxidase, KSCN and hydrogen peroxide. The glucose incorporation by late-log cells of S. mutans 10449, serotype c, was followed by measuring the uptake of 14C-glucose at 37 degrees C. At pH 5.5 and 6.5 both immune whey product and HOSCN/OSCN- dose-dependently inhibited glucose uptake. The inhibition by their combination was additive if bacterial cells were treated with HOSCN/OSCN- before exposed to immune whey product. In contrast to immune whey product, the control product from sham-immunized cows increased the glucose uptake even when added simultaneously with HOSCN/OSCN-. However, when bacterial cells were pretreated with HOSCN/OSCN- an enhanced inhibitory effect was observed also with control product. The results indicate that colostral proteins from S. mutants- or S. sobrinus-immunized cows inhibit glucose uptake and that the effect is enhanced by pretreatment with lactoperoxidase-generated HOSCN/OSCN-.

Adjuvants, Immunologic↗

PubMed1997

Mutans streptococci and incipient caries adjacent to glass ionomer cement or resin-based composite in orthodontics.

Levels of mutans streptococci in plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) (Ketac-Cem) and a resin-based composite (CR) (Concise) were investigated, using the split mouth technique in 11 patients who, before treatment, had more than 10(5) CFU of these microorganisms. After full-term orthodontic treatment (mean 9.5 months), the percentage of mutans streptococci of total CFU count in plaque was lower adjacent to GIC-retained brackets (mean 3.9) than adjacent to CR-retained brackets (6.7), but the difference was not statistically significant. Two subjects harbored S. sobrinus. These subjects were the only ones who developed incipient caries during the orthodontic treatment. Incipient lesion formation occurred only adjacent to CR-retained brackets. This suggests that in patients who have relatively high salivary levels of mutans streptococci before treatment and especially in those who harbor S. sobrinus, the use of GIC for bonding may prevent incipient caries formation during orthodontic treatment.

Adolescent↗

PubMedDate not supplied

Inhibitory activity of glass-ionomer cements on cariogenic bacteria.

This study evaluated the antibacterial activity of the glass-ionomer cements Vitrebond (3M ESPE), Ketac Molar (3M ESPE) and Fuji IX (GC America) against S mutans, S sobrinus, L acidophilus and A viscosus, using the agar diffusion test. Inocula were obtained by the seed of indicators cultures in BHI broth incubated at 37 degrees C for 24 hours. Base layers containing 15 mL of BHI agar and 300 microL of each bacteria suspension were prepared in Petri dishes. Six wells measuring 4 mm in diameter were made in each plate and completely filled with one of the testing materials. A 0.2% chlorhexidine solution applied in round filter papers was used as control. Tests were performed 12 times for each material and bacteria strain. After incubation of the plates at 37 degrees C for 24 hours, the zones of bacterial growth inhibition around the wells were measured. Overall, the results showed the following sequence of antibacterial activity: Vitrebond (despite the activation mode) > 0.2% chlorhexidine > Ketac Molar > Fuji IX, according to Kruskal-Wallis and Mann-Whitney statistical tests. This study confirmed significant antibacterial activity for two conventional glass-ionomers and one resin-modified glass-ionomer material. The resin-modified glass-ionomer cement Vitrebond, regardless of the activation mode, presented the best antibacterial activity against S mutans and S sobrinus. The antibacterial activity against A viscosus for Vitrebond was similar to 0.2% chlorhexidine, while light activation reduced its antibacterial activity against L acidophilus.

Actinomyces viscosus↗

PubMed1988

The effect of desalivation on coronal and root surface caries in rats.

Although the presence of coronal caries is declining in much of the Western Hemisphere, the prevalence of root surface caries is likely to increase as teeth are retained longer than heretofore. At the same time, an increasing number of the population suffer from dry mouth as a result of taking prescription drugs, with an apparent concomitant increased susceptibility to root surface caries. This study attempted to develop an animal model which would aid in the exploration of the effects of desalivation and the development of root surface caries. Animals were desalivated, infected with Actinomyces viscosus and Streptococcus mutans (sobrinus) 6715, and fed a cariogenic diet. Coronal caries developed rapidly in the animals; sufficient disease was present after two weeks to permit evaluation of potential therapeutic agents. Alveolar bone loss and root surface lesions developed in three to four weeks. S. mutans (sobrinus) and A. viscosus established readily in all animals; however, as the investigation progressed, populations of the latter declined, possibly because of the highly acidogenic environment. This model will facilitate investigation of the influence of hyposalivation and help in the exploration of agents to alleviate the adverse effects of salivary gland dysfunction.

Actinomyces viscosus↗

PubMed1996

Antibacterial activity of fluoride release sealants on mutans streptococci.

This study was conducted to study the antibacterial activity of sealants on mutans streptococci. The antibacterial effect of fluoride release sealants was estimated by using agar plates infected with several strains of S. mutans and S. sobrinus. Both bacterial groups were sensitive to sealant antibacterial activity, there was not statistical difference in the inhibition between both groups. The Teethmate-F was the only active material in this study and showed more than four times fluoride release than FluoroShield. The inhibition activity was associated with sealant fluoride release after the setting of this material.

Anti-Infective Agents, Local↗

PubMed2000

Inhibitory effects of apple polyphenols and related compounds on cariogenic factors of mutans streptococci.

The inhibitory effects of apple polyphenols (APP) on the synthesis of water-insoluble glucans by glucosyltransferases (GTF) of streptococci of the mutans group and on the sucrose-dependent adherence of the bacterial cells were examined in vitro. APP markedly inhibited the activity of GTF purified from the cariogenic bacterial cells. However, APP showed no significant effect on the growth of the cariogenic bacteria. The strongest GTF inhibitors in APP were apple condensed tannins (ACT), a mixture of procyanidins. The 50% inhibitory doses of ACT against the GTF of S. sobrinus and that of S. mutans were 1.5 microgram/mL and 5 microgram/mL, respectively. The ACT efficacy largely depended upon the degree of polymerization. Interestingly, while the other polyphenols known to inhibit GTF such as tannic acid markedly inhibited salivary alpha-amylase activity, APP and ACT only scarcely inhibited that enzyme activity. This means that APP and ACT might selectively inhibit the bacterial GTF activity under oral conditions.

Bacterial Adhesion↗