Quantitative real-time polymerase chain reaction for Streptococcus mutans and Streptococcus sobrinus in dental plaque samples and its association with early childhood caries

The formation of cariogenic plaque to contemporary adhesive restorative materials: an in vitro study

The research exploiting the ability of dental materials to induce or prevent secondary caries (SC) development still seems inconclusive. Controlling bacterial adhesion by releasing bacteriostatic ions and improving the surface structure has been suggested to reduce the occurrence of SC. This paper analyses the impact of five distinctively composed dental materials on cariogenic biofilm formation. Forty-five specimens of three composites (CeramX Spectra ST, Admira Fusion, Beautifil II) and two glass-ionomers (Fuji II LC, Caredyne Restore), respectively, were incubated in bacterial suspension composed of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius at pH 7.0 and 5.5. Coverslips were used as a control. Adhered bacteria were collected after 2, 4, 6, 12, 24, and 48 h and analyzed using quantitative polymerase chain reaction (qPCR). Fluoride leakage was measured at each collection. The specimens' surface topography was assessed using interferometry. In the present study, surface roughness seemed to have a partial role in bacterial adhesion and biofilm formation, together with chemical composition of the materials tested. Despite differences in fluoride leakage, biofilm accumulation was similar across materials, but the number of adhered bacteria differed significantly. A release of other ions may also affect adhesion. These variations suggest that certain materials may be more prone to initiating secondary caries.

Effect of silver diamine fluoride upon the microbial community of carious lesions: A scoping review

OBJECTIVES

To explore the effects of silver diamine fluoride (SDF) on the microbial community of carious lesions.

DATA

Original studies evaluating the effect of SDF treatment on the microbial community of human carious lesions were included.

SOURCES

A systematic search of English-language publications was performed in PubMed, EMBASE, Scopus, and Web of Science. Gray literature was searched in ClinicalTrials.gov and Google Scholar.

STUDY SELECTION/RESULTS

This review included seven publications reporting the effects of SDF on microbial community of dental plaque or carious dentin, including the microbial biodiversity, relative abundance of microbial taxa, and predicted functional pathways of the microbial community. The studies on microbial community of dental plaque reported that SDF did not have a significant effect on both the within-community species diversity (alpha-diversity) and inter-community microbial compositional dissimilarity (beta-diversity) of the plaque microbial communities. However, SDF changed the relative abundance of 29 bacterial species of plaque community, inhibited carbohydrate transportation and interfered with the metabolic functions of the plaque microbial community. A study on the microbial community in dentin carious lesions reported that SDF affected its beta-diversity and changed the relative abundance of 14 bacterial species.

CONCLUSION

SDF showed no significant effects on the biodiversity of the plaque microbial community but changed the beta-diversity of the carious dentin microbial community. SDF could change the relative abundance of certain bacterial species in the dental plaque and the carious dentin. SDF could also affect the predicted functional pathways of the microbial community.

CLINICAL SIGNIFICANCE

This review provided comprehensive evidence on the potential effect of SDF treatment on the microbial community of carious lesions.

Quantitative analysis of salivary and biofilm bacteria associated with cavitated and non-cavitated carious lesions in pre-school children

OBJECTIVE

To quantify and compare Streptococcus mutans (S. mutans) and Lactobacillus fermentum (L. fermentum) in saliva and biofilm of caries-free children to those with cavitated and non-cavitated lesions.

DESIGN

One hundred and thirty-five 3-4 years old children were grouped (n = 45 in each group) according to their caries status: Clinical examination was done by a calibrated examiner. Biofilm and saliva were collected to quantify the microorganisms using qRT-PCR. The decayed-missing-filled surfaces (dmfs) was calculated by adding the number of decayed (ICDAS-II score 3-6), filled (ICDAS-II score 7 and 8) and missing (ICDAS-II score 9) surfaces due to caries. The correlation between the bacterial amounts and the number of carious surfaces was evaluated using Spearman's correlation coefficient. The levels and proportions of the microorganisms were compared using the Kruskal-Wallis test at an α-level of 0.05.

RESULTS

The quantity of S. mutans and L. fermentum was significantly higher in saliva and biofilm of children with cavitated lesions, followed by those with non-cavitated lesions and the lowest in caries-free children. Also, salivary and biofilm S. mutans, along with biofilm L. fermentum levels, significantly correlated with the number of non-cavitated surfaces; while salivary and biofilm S. mutans and L. fermentum levels significantly correlated with the number of cavitated surfaces. Additionally, dmfs scores significantly correlated with the salivary and biofilm S. mutans and L. fermentum levels.

CONCLUSIONS

S. mutans and L. fermentum in saliva and biofilm samples are associated with caries lesion severity.

Identification and Correlation of Streptococcus mutans and Streptococcus sanguinis in Caries-active and Caries-free Children: A PCR Study

Aim and objectives

Dental caries is currently considered an ecological imbalance within the oral biofilm leading to the dissolution of the tooth's hard tissues. It has been traditionally thought that two species belonging to the Streptococci group, Streptococcus mutans (SM) and Streptococcus sanguinis (SS), are the etiologically responsible for the onset of dental decay.

Materials and methods

The present in vivo study was conducted on 40 children with caries-active (CA) and caries-free (CF). They were allocated into two groups, group I (CA) = 20 and group II (CF) = 20. The whole saliva was collected into the vials with buffer solution and was stored in cold storage. Polymerase chain reaction (PCR) was done to identify and correlate SM and SS in CA and CF children.

Results

Comparison of mean SM level between CA and CF groups showed a statistically significant result at p = 0.001. Spearman's correlation between caries score and SM showed a strong correlation of 0.77 between caries score and SM, which was statistically significant at p = 0.001. Similarly, SS and caries scores showed a weak correlation of 0.22. Simple linear regression analysis to SM and caries score showed a significant increase of 4.74 units for 1 score increase in caries score, which is statistically significant.

Conclusion

The presence of SM levels in children with caries is significant, whereas, in CF children, SS levels are present in increased levels. A strong correlation was seen between caries scores and SM. The simple linear regression analysis predicts a statistically significant increase by 4.74 units per increase of 1 score of caries at p < 0.001. As caries increase, SM count increases, but SS count decreases; as SS count increases, there is a reduction in SM counts.

How to cite this article

Thimmegowda U, Belagatta V, Chikkanarasaiah N, et al. Identification and Correlation of Streptococcus mutans and Streptococcus sanguinis in Caries-active and Caries-free Children: A PCR Study. Int J Clin Pediatr Dent 2023;16(1):9-15.

Streptococcus sobrinus as a Predominant Oral Bacteria Related to the Occurrence of Dental Caries in Polish Children at 12 Years Old

Dental caries is listed by the WHO as one of the major non-communicable diseases that need to be prevented and treated. The aim of the study was to evaluate the prevalence and severity of caries expressed as the Decayed, Missing and Filled Permanent Teeth (DMFT) index in 12-year-old Polish children and to verify bacterial species related to the occurrence of dental caries. Quantitative real-time PCR analysis of DNA isolated from saliva samples was performed to detect 8 cariogenic and periopathogenic bacterial strains. A total of 118 Polish children were enrolled in the study. They had low mean DMFT scores of 1.58 ± 1.98. The prevalence of dental caries in the children tested was low (53.4%), with a tendency to decrease compared to previous oral surveys. Bacterial abundance of other species in the dental caries and caries-free groups did not differ; however, periopathogenic Prevotella pallens, Fusobacterium nucleatum along with cariogenic Streptococcus mutans and Lactobacillus fermentum were significantly strongly correlated in the caries-active subjects. The prevalence of S. sobrinus was significantly higher in children with dental caries (p = 0.023) and correlated with higher DMFT. It may temporarily play an important role in the initiation of the cariogenic process or in its enhancement due to an ecological imbalance in dental microbiota.

Candida albicans CHK1 gene regulates its cross-kingdom interactions with Streptococcus mutans to promote caries

The cross-kingdom interactions between Candida albicans and Streptococcus mutans have played important roles in early childhood caries (ECC). However, the key pathways of C. albicans promoting the cariogenicity of S. mutans are still unclear. Here, we found that C. albicans CHK1 gene was highly upregulated in their dual-species biofilms. C. albicans chk1Δ/Δ significantly reduced the synergistical growth promotion, biofilm formation, and exopolysaccharides (EPS) production of S. mutans, the key cariogenic agent, compared to C. albicans wild type (WT) and CHK1 complementary strains. C. albicans WT upregulated the expressions of S. mutans EPS biosynthesis genes gtfB, gtfC, and gtfD, and their regulatory genes vicR and vicK, but chk1Δ/Δ had no effects. Both C. albicans WT and chk1Δ/Δ failed to promote the biofilm formation and EPS production of S. mutans ΔvicK and antisense-vicR strains, indicating that C. albicans CHK1 upregulated S. mutans vicR and vicK to increase the EPS biosynthesis gene expression, then enhanced the EPS production and biofilm formation to promote the cariogenicity. In rat caries model, the coinfection with chk1Δ/Δ and S. mutans decreased the colonization of S. mutans and developed less caries especially the severe caries compared to that from the combinations of S. mutans with C. albicans WT, indicating the essential role of C. albicans CHK1 gene in the development of dental caries. Our study for the first time demonstrated the key roles of C. albicans CHK1 gene in dental caries and suggested that it may be a practical target to reduce or treat ECC. KEY POINTS: • C. albicans CHK1 gene is important for its interaction with S. mutans. • CHK1 regulates S. mutans two-component system to promote its cariogenicity. • CHK1 gene regulates the cariogenicity of S. mutans in rat dental caries.

Oral Microbiome and Dental Caries Development

Dental caries remains the most prevalent oral disease worldwide. The development of dental caries is highly associated with the microbiota in the oral cavity. Microbiological research of dental caries has been conducted for over a century, with conventional culture-based methods and targeted molecular methods being used in order to identify the microorganisms related to dental caries. These methods’ major limitation is that they can identify only part of the culturable microorganisms in the oral cavity. Introducing sequencing-based technology and bioinformatics analysis has boosted oral microbiome research and greatly expanded the understanding of complex oral microbiology. With the continuing revolution of molecular technologies and the accumulated sequence data of the oral microbiome, researchers have realized that microbial composition alone may be insufficient to uncover the relationship between caries and the microbiome. Most updated evidence has coupled metagenomics with transcriptomics and metabolomics techniques in order to comprehensively understand the microbial contribution to dental caries. Therefore, the objective of this article is to give an overview of the research of the oral microbiome and the development of dental caries. This article reviews the classical concepts of the microbiological aspect of dental caries and updates the knowledge of caries microbiology with the results of current studies on the oral microbiome. This paper also provides an update on the caries etiological theory, the microorganisms related to caries development, and the shifts in the microbiome in dental caries development.

Association between Bifidobacterium and Scardovia Wiggsiae and caries-related factors in severe early childhood caries and caries-free Thai children: a quantitative real-time PCR analysis and a questionnaire cross-sectional study

AIMS

To quantitatively identify Bifidobacterium, S. wiggsiae and S. mutans in plaque samples obtained from children with severe-ECC and caries-free groups and to analyze their association with caries-related factors retrieved from the questionnaire in each group.

STUDY DESIGN

To establish the 2 study groups, clinical examination in 122 Thai children, aged 2-5 years, recorded decayed, missing and filled teeth scores (dmft), in addition to plaque and gingival indices. Sixty one children in the caries-free group and 61 in the S-ECC group were identified. A questionnaire was used to assess the parent's attitudes and behavior regarding the child's oral hygiene care and diet.

METHODS

Pooled overnight supra gingival plaque was collected from each child using a sterile toothpick, released in 1 ml of TE buffer, transported on ice to the Laboratory and stored at  - 20 °C. DNA was extracted from the plaque based on enzymatic lysis and quantitative real-time PCR using fluorescent dye (SYBR green) in addition to Agarose gel electrophoresis were performed. All laboratory and retrieved from the questionnaire data per child were recorded and statistically analysed.

RESULTS

S. wiggsiae (p < 0.005) and S. mutans (p < 0.001) were higher in the S-ECC group. Bifidobacterium, S. mutans, and S. wiggsiae were associated with the dmft score and gingival index (p < 0.001). The dmft scores of children who detected only S. mutans were significantly lower than the dmft scores of children who detected two bacteria; S. mutans + S. wiggsiae (p = 0.028), S. mutans + Bifidobacterium (p = 0.026), and three bacteria; S. mutans + Bifidobacterium + S. wiggsiae (p = 0.007). Children who found all three bacteria (Bi + Sm + Sw) had the highest dmft scores, followed by children who had two bacteria (Bi + Sw, or Bi + Sm, or Sw + Sm). The guardians' education levels, occupations, household income, prolonged bottle feeding, taking of water after bottle or breast feeding, eating sugar-coated crackers or bread with sweetened cream, and premature birth were the factors that related to S-ECC.

CONCLUSION

Levels of S. wiggsiae and S. mutans, guardian's education, family economics, prolonged bottle feeding, eating high sugar-containing snacks and premature birth were associated with S-ECC.

Oral colonization of Candida albicans and Streptococcus mutans in children with or without fixed orthodontic appliances: A pilot study

Background/purpose

Adolescents undergoing fixed orthodontic therapy have an increased risk of oral diseases due to additional plaque accumulation sites. However, the effect of fixed orthodontics appliances (FOAs) on the colonization of Candida albicans (Ca) and Streptococcus mutans (Sm), two synergistic oral pathogens, is largely unknown and was, therefore, the primary objective of this pilot investigation.

Material and methods

Sixteen children aged 10–15 years were enrolled, nine in the FOA and seven in the control groups. Saliva and occlusal plaque were collected, and the Ca and Sm levels were quantified with a quantitative real-time polymerase chain reaction (qPCR) assay.

Results

A trend of higher Ca levels was observed in the saliva and occlusal plaque of the FOA group, while the control group contained higher levels of Sm. Furthermore, for Sm levels, a positive correlation between saliva and occlusal plaque was shown in both the FOA and control groups; in contrast, Ca levels were negatively correlated between these samples only in the FOA group. Between Ca and Sm, a positive correlation was observed in saliva and occlusal plaque in the control group; however, this relationship was disrupted in the FOA group.

Conclusion

Our preliminary study demonstrated that the presence of FOAs disturbs the colonization of Ca and Sm within the oral cavity. This perturbation might increase orthodontic patients’ risk for Ca- and Sm-related diseases.

Evaluation of the antibacterial effects and mechanism of Plantaricin 149 from Lactobacillus plantarum NRIC 149 on the peri-implantitis pathogens

Peri-implantitis is a common reversible disease after tooth implantation, caused by a variety of pathogenic microorganisms. Based on non-surgical or surgical treatment principles, supplementation by local or systemic drugs might enhance treatment efficacy. Porphyromonas gingivalis (Pg) (ATCC 33,277) and Prevotella intermedius (Pi) (ATCC 25,611) were used as test strains. The effects of Pln 149 on the biofilm formation and growth of four periodontal pathogens were evaluated by RT-PCR, fluorescence microscopy, and scanning electron microscopy. The antibacterial mechanism was tested by the patch-clamp technique. The cytotoxicity of Pln 149 (125 µg/ml) to bone marrow stromal cell (BMSC) was assessed using an MTT assay. Pln 149 exhibited significant inhibitory effects on Pg and Pi (P < 0.05), with significant differences in the biofilm images of fluorescence microscope and scanning electron microscope (P < 0.05). Pln 149 could change the sodium channel currents and exerted no cytotoxicity on bone marrow stromal cell. Pln 149 could inhibit the biofilm formation and growth of periodontal pathogens. Considering the absence of antimicrobial resistance and cytotoxicity, we suggest that the Pln 149 from Lactobacillus plantarum 149 might be a promising option for managing peri-implantitis.

Effect of drops containing Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) on plaque acidogenicity and other caries-related variables in orthodontic patients

BACKGROUND

The purpose of the study was to investigate the effect of probiotics on biofilm acidogenicity and on the number of salivary Streptococcus mutans and lactobacilli in orthodontic patients.

METHODS

This RCT was conducted on 28 young adults who were undergoing orthodontic treatment. The short-term prospective clinical trial lasted for three weeks. The test group rinsed daily with drops containing two Lactobacillus reuteri strains diluted in water, while the placebo group used drops without probiotics. The subjects were enrolled eight months since the beginning of orthodontic treatment. Plaque-pH, saliva and dental biofilm samples were obtained at baseline, one week and three weeks post intervention.

RESULTS

Twenty-seven subjects successfully completed the trial period, only one drop out in the test group. No side effects were reported. A statistically significant increase in plaque pH at three weeks post-intervention was found for the test group (p < 0.05), while insignificant changes in the pH value were found for the placebo group in comparison to baseline (p > 0.05). In addition, the AUC_7.0 showed a significant difference at three weeks between the test and placebo (p = 0.00002). The three-week samples of stimulated whole saliva showed a statistically insignificant difference in the number of S. mutans and lactobacilli between the two groups (p > 0.05). The qPCR analysis showed the ability of the two strains to get colonized in the dental biofilm without a significant effect on the microbial counts.

CONCLUSION/CLINICAL IMPLICATIONS

A mixture of Lactobacillus reuteri has the ability to reduce the pH fall at the three-week follow-up. However, the short-term use of probiotics does not appear to have an effect on the number of salivary Streptococcus mutans and lactobacilli in saliva and on the dental biofilm.

TRIAL REGISTRATION

Clinicaltrial.gov (Identifier: NCT04593017 / (19/10/2020)).

Mutans Streptococci and Lactobacilli: Colonization Patterns and Genotypic Characterization of Cariogenic Bacterial Species in American Indian Children

Aim: The purpose of this study was to investigate the presence of Streptococcus mutans, Streptococcus sobrinus, and Lactobacillus species in an American Indian population displaying a high incidence of severe early childhood caries (S-ECC) and to explore the genotypic diversity and fidelity of transmission of S. sobrinus in this population.

Methods: We report here on the microbial profiles of 71 children compiled from birth to 36 months of age and initial exploration of genotypic diversity in a subset of 40 mother/child dyads. Whole mouth plaque samples were collected from mother/child dyads in a Northern Plains American Indian cohort. Mutans streptococci (MS) and Lactobacillus counts were recorded and presence/absence of S. mutans, S. sobrinus, and Lactobacillus was noted for each child. S. sobrinus was isolated and genotyped via arbitrarily primed-polymerase chain reaction (AP-PCR).

Results: The children in this study were divided into caries active (CA) and caries free (CF) groups. S. mutans, S. sobrinus, and Lactobacillus species were detected more frequently in CA groups. Distribution of MS and Lactobacillus counts was significantly different between the two groups, as was the distribution of three species colonization profiles. Twelve S. sobrinus genotypes were detected in the subset of mother/child dyads. Individual participants displayed a range of 0–3 distinct genotypes while mother/child pairs displayed a range of 1–5 genotypes. Eighty-three percent of children shared at least one genotype with his/her mother.

Conclusion: Caries active children in this population display different microbial profiles than the caries free children in this cohort. A small number of S. sobrinus genotypes appear to be very common in this population. A high rate of vertical transmission of S. sobrinus from mother to child is seen in these mother/child dyads.

Comparative Evaluation of Antibacterial Effect of GIC Containing Chlorhexidine and Miswak on Streptococcus mutans and Streptococcus sobrinus in Early Childhood Caries Children: A PCR Study

Background and aim

The therapeutic procedures used in the treatment of caries do not always eliminate all the microorganisms. Persisting cariogenic bacteria can cause recurrent caries and failure of restoration. Incorporation of an antimicrobial agent in the restorative material may be of paramount significance. The purpose of this study was to evaluate and compare the antibacterial effect of glass ionomer cement (GIC) containing CHX and miswak extract on Streptococcus mutans and Streptococcus sobrinus in ECC children using polymerase chain reaction (PCR).

Materials and methods

Forty-five children with ECC in the age-group 3–6 years were selected. The children were randomly allocated into three groups. Supragingival plaque samples (S1) were collected from sound buccal or labial surfaces of primary teeth. Cavity preparation was done and the teeth were restored according to the group to which the child had been allotted. The second plaque sample (S2) was collected 1 month and the final sample after 3 months of restoring all the decayed teeth. All the samples were sent for PCR analysis.

Results

Intergroup analysis was done using Kruskal–Wallis test followed by Mann–Whitney post hoc test showed statistically significant difference in S. mutans and S. sobrinus count between group I (CHX) and group III (control) and group II (miswak) and group III (control) but no statistically significant difference between group I (CHX) and group II (miswak) in S. mutans and S. sobrinus count.

Conclusion

1% chlorhexidine digluconate and aqueous extract of miswak are equally effective against S. mutans and S. sobrinus. Miswak can be used as an alternative herbal antimicrobial that can be incorporated in anhydrous GIC.

How to cite this article

Kalpavriksha AJ, Siddaiah SB, Bilichodmath S, et al. Comparative Evaluation of Antibacterial Effect of GIC Containing Chlorhexidine and Miswak on Streptococcus mutans and Streptococcus sobrinus in Early Childhood Caries Children: A PCR Study. Int J Clin Pediatr Dent 2021;14(2):229–234.

The role of sugar-rich diet and salivary proteins in dental plaque formation and oral health

BACKGROUND

Dental plaque is a complex colorless film of bacteria that develops on the surfaces of teeth. Different mechanisms of microbial adhesion to tooth surfaces exist. Both non-specific and specific types of adherence have been anticipated.

HIGHLIGHT

The present review evaluated the effect of sugar-rich diet and salivary proteins on oral hygiene and dental plaque development.

CONCLUSION

The oral microbiota is essential for maintaining and reestablishing a healthy oral cavity. Different types of sugars have different effects on the inhibition and formation of dental plaque. The peptides, proteins, and amino acids secreted by parotid glands in the oral cavity facilitate neutralizing the acidity in dental plaque and preventing dental caries. A properly balanced diet is crucial for both a healthy oral cavity and the oral microbiome.

Opportunities for caries prevention using an ion-releasing coating material: a randomised clinical study

Ion-releasing materials (containing fluoride and boron, for example) have shown caries-preventive effects in vitro. The purpose of the present study was to investigate the impact of multi-ion-releasing coating material on pH stabilisation, plaque accumulation and the bacterial composition of dental plaque during a time period of 90 days. The null hypothesis tested here was that the evaluated material would not show any differences in pH stabilisation, plaque accumulation or bacterial composition compared with control material.

The study was carried out as a double-blind, split-mouth, randomised, controlled clinical trial in 28 volunteers. Over the evaluation period (days 4, 30, 60 and 90), pH measurements, plaque index and plaque sampling for bacterial analyses were conducted in a calibrated, standardized manner. The study received ethical permission and was carried out in accordance with the Helsinki Declaration.

A significant difference was observed, with less plaque accumulation over time in the subjects in whom the ion-releasing material was applied in comparison to the non-active group. No significant difference was evident in terms of either pH stabilisation or plaque levels of mutans streptococci.

The null hypothesis relating to plaque accumulation was rejected, with a lower plaque index shown for the test group up to 60–90 days. No adverse effects during the observation period were observed. Since the studied cohort was healthy from a caries perspective, more clinical studies are needed to further evaluate the caries-prevention potential of the ion-releasing material in other patient groups.

Dental adhesive microtensile bond strength following a biofilm-based in vitro aging model

OBJECTIVE

Laboratory tests are routinely used to test bonding properties of dental adhesives. Various aging methods that simulate the oral environment are used to complement these tests for assessment of adhesive bond durability. However, most of these methods challenge hydrolytic and mechanical stability of the adhesive- enamel/dentin interface, and not the biostability of dental adhesives. To compare resin-dentin microtensile bond strength (μTBS) after a 15-day Streptococcus mutans (SM) or Streptococcus sobrinus (SS) bacterial exposure to the 6-month water storage (WS) ISO 11405 type 3 test.

METHODOLOGY

A total of 31 molars were flattened and their exposed dentin was restored with Optibond-FL adhesive system and Z-100 dental composite. Each restored molar was sectioned and trimmed into four dumbbell-shaped specimens, and randomly distributed based on the following aging conditions: A) 6 months of WS (n=31), B) 5.5 months of WS + 15 days of a SM-biofilm challenge (n=31), C) 15 days of a SM-biofilm challenge (n=31) and D) 15 days of a SS-biofilm challenge (n=31). μTBS were determined and the failure modes were classified using light microscopy.

RESULTS

Statistical analyses showed that each type of aging condition affected μTBS (p<0.0001). For Group A (49.7±15.5MPa), the mean μTBS was significantly greater than in Groups B (19.3±6.3MPa), C (19.9±5.9MPa) and D (23.6±7.9MPa). For Group D, the mean μTBS was also significantly greater than for Groups B and C, but no difference was observed between Groups B and C.

CONCLUSION

A Streptococcus mutans- or Streptococcus sobrinus-based biofilm challenge for 15 days resulted in a significantly lower μTBS than did the ISO 11405 recommended 6 months of water storage. This type of biofilm-based aging model seems to be a practical method for testing biostability of resin-dentin bonding.

Consumer Safety Considerations of Skin and Oral Microbiome Perturbation

Microbiomes associated with human skin and the oral cavity are uniquely exposed to personal care regimes. Changes in the composition and activities of the microbial communities in these environments can be utilized to promote consumer health benefits, for example, by reducing the numbers, composition, or activities of microbes implicated in conditions such as acne, axillary odor, dandruff, and oral diseases. It is, however, important to ensure that innovative approaches for microbiome manipulation do not unsafely disrupt the microbiome or compromise health, and where major changes in the composition or activities of the microbiome may occur, these require evaluation to ensure that critical biological functions are unaffected. This article is based on a 2-day workshop held at SEAC Unilever, Sharnbrook, United Kingdom, involving 31 specialists in microbial risk assessment, skin and oral microbiome research, microbial ecology, bioinformatics, mathematical modeling, and immunology. The first day focused on understanding the potential implications of skin and oral microbiome perturbation, while approaches to characterize those perturbations were discussed during the second day. This article discusses the factors that the panel recommends be considered for personal care products that target the microbiomes of the skin and the oral cavity.

A pilot study to assess oral colonization and pH buffering by the probiotic Streptococcus dentisani under different dosing regimes

Bacterial colonization in the oral cavity is critical for efficient action of probiotics. However, limited colonization rates have been reported in many clinical trials. The aim of this pilot clinical study was to evaluate the colonization efficiency of Streptococcus dentisani under different dosing schedules and pre-treatment conditions. Eleven adult volunteers enrolled in the study. A professional ultrasound cleaning was performed in quadrants 1 and 4. The probiotic was applied in all four quadrants at a total dose of 10¹⁰ CFUs, administered in a buccoadhesive gel for 5 min, either in a single dose (n = 5) or daily for a week (n = 6). Dental plaque and saliva samples were collected at baseline and after 14 and 28 days of first application. Amounts of S. dentisani and the cariogenic organism Streptococcus mutans were measured by qPCR and salivary pH was measured by reflectometry. There was a significant increase in S. dentisani cells at day 14 but not at day 28 under both dosing schedules. A non-significant higher colonization was found in the half-mouth with previous professional cleaning as compared to the intact half. There was a significant increase in salivary pH at day 14 (p = 0.024) and day 28 (p = 0.014), which was stronger in multi-dose patients, and a significant decrease in S. mutans at day 28 (p < 0.01). The results indicate that S. dentisani is transiently able to colonize the oral cavity and that it buffers oral pH, especially after multiple dosing. Future randomized, placebo-controlled clinical trials should evaluate its use to prevent tooth decay.

Impact of polyols on Oral microbiome of Estonian schoolchildren

BACKGROUND

Oral microbiome has significant impact on both oral and general health. Polyols have been promoted as sugar substitutes in prevention of oral diseases. We aimed to reveal the effect of candies containing erythritol, xylitol or control (sorbitol) on salivary microbiome.

METHODS

Ninety children (11.3 ± 0.6 years) consumed candies during 3 years. Microbial communities were profiled using Illumina HiSeq 2000 sequencing and real-time PCR.

RESULTS

The dominant phyla in saliva were Firmicutes (39.1%), Proteobacteria (26.1%), Bacteroidetes (14.7%), Actinobacteria (12%) and Fusobacteria (6%). The microbiome of erythritol group significantly differed from that of the other groups. Both erythritol and xylitol reduced the number of observed bacterial phylotypes in comparison to the control group. The relative abundance of the genera Veillonella, Streptococcus and Fusobacterium were higher while that of Bergeyella lower after erythritol intervention when comparing with control. The lowest prevalence of caries-related mutans streptococci corresponded with the lowest clinical caries markers in the erythritol group.

CONCLUSIONS

Daily consumption of erythritol, xylitol or control candies has a specific influence on the salivary microbiome composition in schoolchildren. Erythritol is associated with the lowest prevalence of caries-related mutans streptococci and the lowest levels of clinical caries experience.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT01062633.

Effect of polyphenol-rich cranberry extracts on cariogenic biofilm properties and microbial composition of polymicrobial biofilms

OBJECTIVE

To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria.

METHODS

Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated for 2 min every 12 h over the entire biofilm growth period with 500 μg/mL cranberry extract or vehicle control. The effect of the cranberry extract on biofilm behaviour was evaluated using different assays and its influence on key cariogenic and health-associated bacterial populations was assessed with a microarray real-time quantitative PCR method.

RESULTS

Cranberry-treated biofilms showed significant drops in biomass (38% reduction, P <  0.001), acidogenicity (44% reduction, P <  0.001), EPS/microbial biovolume ratios (P =  0.033), and CFU counts (51% reduction, P =  0.001). Furthermore, the cranberry extracts effected a significantly lower relative abundance of caries-associated Streptococcus sobrinus (fold change 0.004, P =  0.002) and Provotella denticola (0.002, P <  0.001), and a significantly higher relative abundance of the health-associated Streptococcus sanguinis (fold change 90.715, P =  0.001).

CONCLUSIONS

The cranberry extract lowered biofilm biomass, acidogenicity, EPS/microbial biovolumes, CFU counts, and modulated a beneficial microbial ecological change in saliva-derived polymicrobial biofilms.

Evaluation of Antibacterial Effect of Propolis and its Application in Mouthwash Production

Objectives:

Our purpose was to determine the antibacterial properties of propolis and to evaluate its use as an antibacterial mouthwash with minimal complications.

Materials and Methods:

In this experimental laboratory study, an alcoholic propolis extract was prepared. The minimum inhibitory concentration (MIC) was calculated for four bacterial species including Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Lactobacillus acidophilus (L. acidophilus), and Enterococcus faecalis (E. faecalis) using agar dilution. According to the MIC, a propolis antibacterial mouthwash was produced and compared to water, chlorhexidine (CHX), and Listerine using laboratory rats for clinical examination. Salivary specimens of rats were collected at 12 hours, 1 week, and 2 weeks after using the mouthwash and examined by real-time polymerase chain reaction (RT-PCR). Data were analyzed using one-way analysis of variance (ANOVA) and repeated measures ANOVA (α=0.05).

Results:

The results of agar dilution by the number of colony-forming units showed the lowest MIC for S. aureus and the highest for L. acidophilus. Our RT-PCR findings indicated that water alone had no effect on the level of oral bacteria. Propolis mouthwash showed a significant difference with CHX and Listerine (P<0.05) in terms of the number of S. mutans, E. faecalis, and L. acidophilus colonies, while CHX and Listerine were less efficient. There was no significant difference between CHX and propolis (P=0.110) regarding S. aureus colonies, but Listerine had a lower efficacy than either (P<0.05).

Conclusion:

According to the results, propolis mouthwash was more efficient against the studied oral bacteria compared to CHX and Listerine.

Effect of the addition of chlorhexidine and miswak extract on the clinical performance and antibacterial properties of conventional glass ionomer: an in vivo study

BACKGROUND

Antibacterial restorations can increase the success rate of minimum invasive dentistry especially in young permanent molars with deep carious lesions as an attempt to preserve maximum dental structure and avoid pulp exposure. Further research is warranted to evaluate different antibacterial agents.

OBJECTIVES

This study aimed to evaluate the efficacy of adding chlorhexidine gluconate (CHX) or aqueous miswak (Salvadora persica) extract on the clinical performance and in vivo antibacterial activity of conventional anhydrous glass ionomer cement (GIC).

DESIGN

The study was a randomized clinical trial. Sixty young permanent molars, with deep carious lesions in 6- to 9-year-old children were included. After randomization, atraumatic restorative treatment (ART) or stepwise excavation was performed followed by bacterial sampling from the center of the remaining carious dentine in the floor of the pulp. GIC powder was mixed with 0.5% chlorhexidine gluconate liquid in group I; with 100% aqueous miswak in group II; and with deionized water in group III (control). Clinical performance for all groups was assessed at 3, 6, and 9 months. After 9 months, restorations were removed and a second bacterial sample was collected for Streptococcus mutans (S. mutans) quantification and analysis by real-time polymerase chain reaction (PCR) test.

RESULTS

Results showed no statistically significant difference in the success rate of the three groups at the 3-month interval. At 6 and 9 months, however, restoration success was 75% then 60% in group I, 100% then 90% in group II, and 95% then 85% in control group. Group II and the control group showed statistically significant higher survival rates than group I. All groups showed reduction in S. mutans counts in underlying dentine, but the percent reduction was significantly higher in group I. (P < 0.001).

CONCLUSIONS

The addition of CHX and miswak to GIC showed superior antibacterial properties than conventional GIC, without seriously affecting the clinical performance of the restoration until the 6-month follow-up, but failure significantly increased in terms of marginal defects at 9 months with CHX (group 1).

Quantitative assessment of salivary oral bacteria according to the severity of dental caries in childhood

This study aimed to assess differences in selected oral bacteria in children according to the severity of dental caries. One hundred and thirty-six children, 36-60 months old were divided into three groups according to caries status: caries-free (CF) (n=47), early childhood caries (ECC) (n=40) and severe-early childhood caries (S-ECC) (n=49). Saliva was collected for detection and quantification of selected oral streptococci, Actinomyces naeslundii, Lactobacillus spp., Bifidobacterium spp., and Scardovia wiggsiae by quantitative-polymerase chain reaction. The results showed that the detection and quantitative levels of S. mutans, S. sobrinus, Bifidobacterium spp. and S. wiggsiae were significantly higher in S-ECC children compared to CF and ECC children, while for S. salivarius were significantly higher in CF compared to ECC and S-ECC children. There was no statistical difference among the clinical groups for S. mitis, S. oralis, A. naeslundii and Lactobacillus spp. levels and detection. S-ECC children had a lower monthly family income, started tooth brushing later and were breastfeed for a longer duration compared to CF children. S. mutans levels were positively correlated with S. wiggsiae and Bifidobacterium spp. levels, lower mother's education and child bottle-feeding before sleeping and negatively correlated with S. salivarius. It was concluded that in addition to S. mutans, other bacterial species, including bifidobacteria, Scardovia wiggsiae and S. sobrinus, are associated with severity of early childhood caries, although their role in the progress of dental caries remains unclear.

Scardovia wiggsiae and its potential role as a caries pathogen

BACKGROUND

Streptococcus mutans has been strongly associated with dental caries but caries also occurs in its absence. Association of a new species, Scardovia wiggsiae with childhood caries suggests this could be a new caries pathogen.

HIGHLIGHT

S. mutans is considered a caries pathogen based on its association with caries, and on its ability to produce acid, to survive low pH environments, and to induce caries in experimental animals. S. wiggsiae was significantly associated with severe-early childhood caries in the presence and absence of S. mutans. Further S. wiggsiae was elevated in initial carious lesions in adolescents with fixed orthodontic appliances. S. wiggsiae detection was enriched on a low pH agar suggesting acid-tolerance. S. wiggsiae isolates were acid tolerant and produced acid from several sugars at low initial pH values, and were not arginine deiminase positive, characteristics consistent with potential cariogenicity. Cariogenicity of S. wiggsiae was tested in a rat animal model in parallel with S. mutans. While S. wiggsiae by itself showed minimal caries induction, when co-inoculated with S. mutans, there was significant cavity production.

CONCLUSION

S. wiggsiae was associated with advanced and initial caries, is acid tolerant and produces acid to low pH at initial neutral and low pH conditions. In combination with S. mutans, S. wiggsiae was detected in caries in an animal model. Together, these data suggest that S. wiggsiae has many of the characteristics consistent with its being a caries-associated species.

Oral microbial profiles of individuals with different levels of sugar intake

The aim was to compare the oral microbial profiles in young adults with an intake of free sugars above or below the current recommendations by the WHO for sugar consumption. Seventy subjects completed a Quantitative Food Frequency Questionnaire to establish the proportion of free sugars in relation to the total energy intake (% E). Subjects with <5% E (n = 30) formed the low-sugar group, while those with ≥5% E (n = 40) were regarded as reference group. Saliva and plaque samples were analyzed by qPCR, and 52 of the plaque samples were assayed by HOMINGS. The HOMINGS analysis revealed a comparable core microbiota in plaque samples with Streptococcus, Leptotrichia, Actinobaculum, and Veillonella as predominant. No major differences between groups were revealed by α-diversity testing (p = 0.83), principal component analysis, or correspondence analysis. Higher relative abundance of Streptococcus sobrinus and Prevotella melaninogenica was observed in plaque samples in the reference group. By qPCR, Scardovia wiggsiae was associated with elevated sugar intake. The findings suggests that the amount of ingested sugars had a marginal influence on microbial profiles in dental plaque and saliva. However, some caries-associated species were less abundant in the dental plaque of the low sugar group.

Quantitative analysis of S. mutans, Lactobacillus and Bifidobacterium found in initial and mature plaques in Thai children with early childhood caries

AIMS

To quantify Streptococcus mutans, lactobacillus and bifidobacterium in initial and mature plaque collected from children with severe early childhood caries (S-ECC) and caries-free (CF) groups and to analyse the association between these bacteria and caries-related factors in each group.

STUDY DESIGN

A collection of 120 initial and overnight supra-gingival plaques were collected from Thai children aged 2-5 years-old (S-ECC = 60, CF = 60). Plaque, gingival indices and decayed, missing, filled tooth (dmft) scores were recorded. A questionnaire was used to assess the parents' attitudes and behaviour regarding the child's oral hygiene care and diet.

METHODS

After DNA extraction, quantitative real-time polymerase chain reaction (PCR) using fluorescent dye (SYBR green) was performed.

RESULTS

Levels of Streptococcus mutans, lactobacillus and bifidobacterium in both initial and mature plaques of S-ECC were significantly higher than those from the caries-free group (p < 0.05). The ratio of S. mutans, lactobacillus, and bifidobacterium to the total bacteria in S-ECC was significantly higher than in the caries-free group (p < 0.05). Levels of lactobacillus and bifidobacterium in both plaques significantly correlated with dmft scores and the plaque index, while S. mutans levels only correlated with dmft scores (p < 0.05). Factors that were significantly associated with caries were parents's education, duration of bottle feeding, especially during sleeping and the frequency of consuming cariogenic food between meals (p < 0.05).

CONCLUSION

Levels of S. mutans, lactobacillus, bifidobacterium and the ratio of these bacteria to total bacteria in both initial and mature plaques were significantly higher in children with S-ECC and related to dmft scores, oral hygiene and dietary habits.

Methods of Biotyping of Streptococcus mutans Species with the Routine Test as a Prognostic Value in Early Childhood Caries

Purpose

In order to investigate the suitability of Streptococcus mutans species biotyping by measuring the activity of selected enzymes from a commercial test, criteria were established for biotyping clinical strains from children with dental caries. In addition, the relationships between the selected biotypes, sensitivity to commonly used antibiotics, and early childhood caries were determined.

Methods

A total of 142 S. mutans isolates from dental plaque of children with caries were divided into different biotypes. Patients were divided into two groups: noncavitated (1-2 in ICDAS) and cavitated (5-6 in ICDAS) lesions. Biotyping criteria were determined based on both the arbitrary method and the clusterization method. The susceptibility of the strains to amoxicillin, cefazolin, erythromycin, and teicoplanin was studied by diluting a solid medium.

Results

Biotype I was the most common. Mean MIC values showed that the strains belonging to biotypes II and IV were the most sensitive to amoxicillin. For predetermined biotypes, observed differences were dependent on the severity of dental caries.

Conclusions

The proposed method of S. mutans strains biotyping is relatively quick and simple to use, provided the application of suitable biotyping criteria, and may contribute to the effective prevention of dental caries induced by S. mutans.

Prioritizing the Risk Factors of Severe Early Childhood Caries

Severe early childhood caries remains the most common chronic disease affecting children. The multifactorial etiology of caries has established a controversy about which risk factors were more significant to its development. Therefore, our study aimed through meticulous statistical analysis to arrange the "well agreed upon" common risk factors in order of significance, to aid the clinician in tailoring an adequate preventive program. The study prioritized or reshuffled the risk factors contributing to severe early childhood caries and placed them in the order of their significance as follows: snacking of sugary food several times a day, increased number of siblings to three or more, night feeding, child self-employed brushing, mother's caries experience, two siblings, on demand feeding, once/day sugary food, sharing utensils, one sibling, male gender, father's education, late first dental visit, brushing time, mother's education, no dental visit, decreased brushing frequency, and no night brushing.

Five-year longitudinal study of dental caries risk associated with Streptococcus mutans and Streptococcus sobrinus in individuals with intellectual disabilities

Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) are important etiologic agents in human dental caries. Using quantitative real-time polymerase chain reaction assays for the presence of those strains, we examined 145 outpatients with intellectual disability (ID), calculated the proportion of each of these strains to total bacteria, and compared dental caries incidence over 5 years. Plaque samples were collected from all erupted tooth sites, and dental examinations were performed annually to determine numbers of decayed, missing, and filled teeth (DMFT score; World Health Organization caries diagnostic criteria). Elevated DMFT scores were calculated as ∆DMFT, and sites of newly affected caries (∆SNAC) were identified. Sixty-six patients had both strains. The proportion of S. mutans to total bacteria was moderately correlated with DMFT in year 2, ∆DMFT in years 2 and 5, and ∆SNAC in years 2 and 5 (correlation coefficient = 0.470, P < 0.001), while the proportion of S. sobrinus to total bacteria was moderately correlated with DMFT in years 2 and 5, ∆DMFT in years 1, 2, and 5, and ∆SNAC in years 2 and 5 (correlation coefficient = 0.695, P < 0.001). Individuals with ID who harbored both bacterial strains had a higher risk of dental caries and a significantly higher proportion of S. sobrinus to total bacteria.

Distribution of Streptococcus mutans and Streptococcus sobrinus in Dental Plaque of Indian Pre-School Children Using PCR and SB-20M Agar Medium

INTRODUCTION

Dental caries is one of the most common infectious diseases affecting the oral cavity. Among the oral bacteria, mutans streptococci have been implicated as major cariogenic bacteria as they can produce high levels of dental caries causing substances such as lactic acid and extracellular polysaccharides.

AIM

The aim of the study was to detect the presence of Streptococcus mutans and Streptococcus sobrinus in dental plaque by using Polymerase Chain Reaction (PCR) method, quantification of these micro-organisms using Modified Sucrose-Bacitracin (SB-20M) agar medium and to correlate their presence in Caries Active (CA) and Caries Free (CF) pre-school children.

MATERIALS AND METHODS

Sixty-eight pre-school children, in the age group of 3-5 years were divided equally into 34 CA and 34 CF children. Dental plaque samples were obtained for detection of these microorganisms by PCR method and quantification was done using SB-20M culture medium. The data was analyzed using statistical software SPSS version 16. For statistical analysis, the frequencies and means of Colony Forming Units (CFU) were used with CI = 95%. For bivariate analysis, Fisher exact test was used at 5% level of significance. The comparison of mean of number of CFU of S. mutans and S. sobrinus was made by Mann Whitney U test and Spearman's Rho test at 1% level of significance was used for correlation between dmft and CFU in CA group.

RESULTS

The results showed that S. sobrinus was significantly higher in CA group as compared to CF group whereas S. mutans showed no significant difference. On quantification of these micro-organisms, S. sobrinus was present in significantly higher numbers in CA group as compared to CF group. On correlating the CFU/ml of the micro-organisms with the dmft index, both the micro-organisms showed a positive correlation.

CONCLUSION

We conclude that S. mutans and S. sobrinus were detected in higher numbers in CA children as compared to CF children. PCR is a sensitive, specific, rapid and an effective method for the detection of oral microorganisms.

Frequency of dental caries in active and inactive systemic lupus erythematous patients: salivary and bacterial factors

OBJECTIVE

The objective of this study was to determine dental caries frequency and to analyze salivary and bacterial factors associated with active and inactive systemic lupus erythematous (SLE) patients. Also, a proposal to identify dental caries by a surface, teeth, and the patient was developed.

MATERIAL AND METHODS

A cross-sectional, blinded study that included 60 SLE patients divided into two groups of 30 subjects each, according to the Activity Index for Diagnosis of Systemic Lupus Erythematous (SLEDAI). The decayed, missing, and filled teeth (DMFT) index and Integrative Dental Caries Index (IDCI) were used for analyzing dental caries. The saliva variables recorded were: flow, pH, and buffer capacity. The DNA copies of Streptococcus mutans and Streptococcus sobrinus were estimated by real-time PCR.

RESULTS

The caries frequency was 85% for SLE subjects (73.3% for inactive systemic lupus erythematous (ISLE) and 100% for active systemic lupus erythematous (ASLE)); DMFT for the SLE group was 12.6 ± 5.7 and the IDCI was (9.8 ± 5.9). The ASLE group showed a salivary flow of 0.65 compared with 0.97 ml/1 min from the ISLE group; all variables mentioned above showed a statistical difference (p < 0.05). The salivary pH was 4.6 (6.06 for ISLE and 3.9 for ASLE). The DNA copies of S. mutans and S. sobrinus were high; all variables mentioned above show a significant statistical difference (p < 0.05) between groups.

CONCLUSION

SLE patients had high DMFT and IDCI scores that were associated with a decrease in salivary flow, pH, and buffer capacity. There were high counts of S. sobrinus and S. mutans species, and IDCI is a useful tool to provide more detail about dental caries in epidemiological studies.

Effect of dietary sugars on dual-species biofilms of Streptococcus mutans and Streptococcus sobrinus – a pilot study

Abstract Introduction Frequent consumption of sugars and the presence of Streptococcus mutans and Streptococcus sobrinus are correlated with higher caries experience. Objective The aim of this pilot study was to elucidate the effect of different fermentable carbohydrates on biomass formation and acidogenicity of S. mutans and S. sobrinus biofilms. Material and method Single and dual-species biofilms of S. mutans ATCC 25175 and S. sobrinus ATCC 27607 were grown at the bottom of microtiter plates at equal concentrations for 24 h at 37 °C under micro-aerobic atmosphere. Carbohydrates were added at 2% concentration: maltose, sucrose, glucose and lactose. BHI Broth (0.2% glucose) was used as negative control. Acidogenicity was assessed by measuring the pH of spent culture medium after 24 h, immediately after refreshing the culture medium and for the next 1 h and 2 h. Crystal violet staining was used as an indicator of the total attached biofilm biomass after 24 h incubation. Data were analyzed by two-way ANOVA followed by Bonferroni post hoc test. Significance level was set at 5%. Result All carbohydrates resulted in higher biomass formation in single- and dual-species biofilms when compared to the control group. Sucrose, lactose and maltose showed higher acidogenicity than the control group in both single- and dual-species biofilms after 24 h. Conclusion These findings indicate that the type of biofilm (single- or dual-species) and the carbohydrate used may influence the amount of biomass formed and rate of pH reduction.

Streptococcus mutans and Streptococcus sobrinus colonization and caries experience in 3- and 5-year-old Thai children

OBJECTIVES

The aim of this study was to examine the colonization of Streptococcus mutans and Streptococcus sobrinus in supra-gingival plaque samples and to determine their correlation with the prevalence of early childhood caries (ECC) in Thai children.

MATERIALS AND METHODS

A total of 344 Thai children, ages 3 and 5 years, were invited to participate in this study. Caries status of the children was examined. Supra-gingival plaque samples were collected. Quantitative real-time PCR was performed to evaluate DNA levels of S. mutans and S. sobrinus.

RESULTS

Eighty-five percent of the children were colonized by S. mutans and 50.9% of them were colonized by S. sobrinus. The prevalence of ECC was 43.8% and 56.2% among 3- and 5-year-old children, respectively, and was significantly associated with the presence of S. mutans and S. sobrinus. The severity of ECC was significantly correlated with increased DNA levels of the two bacteria. Children who were positive for S. mutans and S. sobrinus (Sm+/Sb+) were 8 times or 44 times more likely to experience ECC than children who were Sm-/Sb + or were Sm-/Sb-.

CONCLUSIONS

The study evidence further suggest that children colonized by both S. mutans and S. sobrinus are at the higher risk for ECC.

CLINICAL RELEVANCE

Molecular-based qPCR can be used to detect and quantify S. mutans and S. sobrinus colonization for epidemiological and clinical studies for ECC risk assessment.

Real-time PCR quantification of six periodontal pathogens in saliva samples from healthy young adults

OBJECTIVE

The use of saliva as a diagnostic fluid for the evaluation of periodontal health has gained attention recently. Most published real-time PCR assays focused on quantification of bacteria in subgingival plaque, not in saliva. The aims of this study were to develop a real-time PCR assay for quantification of six periodontal pathogens in saliva and to establish a relationship between the amount of DNA (fg) and colony-forming unit (CFU).

MATERIALS AND METHODS

TaqMan primers/probe sets were used for the detection of Aggregatibacter actinomycetemcomitans (Aa), Eikenella corrodens (Ec), Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia (Tf), and total bacteria. Six periodontal pathogens and total bacteria in saliva from 24 periodontally healthy individuals were determined. The relationship between the amount of DNA (fg) and CFU was established by measuring the concentrations of extracted bacterial DNA and CFU per milliliter of bacteria on agar plates.

RESULTS

Fn, Ec, and Pi were detected in all saliva samples, while 58.5, 45.8, and 33.3% were detected for Tf, Pg, and Aa, respectively. Numbers of Ec and Fn in saliva were highly correlated (R(2) = 0.93, P < 0.01). The values of DNA (fg) per CFU ranged from 64 for Ec to 121 for Pg.

CONCLUSION

The real-time PCR assay in combination with the relationship between DNA (fg) and CFU can be used to quantitate periodontal pathogens in saliva and estimate the number of live bacteria (CFU).

CLINICAL RELEVANCE

This real-time PCR assay in combination with the relationship between DNA (fg) and CFU has the potential to be an adjunct in evaluation of periodontal health status.

The usefulness of biotyping in the determination of selected pathogenicity determinants in Streptococcus mutans

Background

Streptococcus mutans is known to be a primary etiological factor of dental caries, a widespread and growing disease in Polish children. Recognition of novel features determining the pathogenicity of this pathogen may contribute to understanding the mechanisms of bacterial infections.

The goal of the study was to determine the activity of prephenate dehydrogenase (PHD) and to illuminate the role of the enzyme in S. mutans pathogenicity. The strains were biotyped based on STREPTOtest 24 biochemical identification tests and the usefulness of biotyping in the determination of S. mutans pathogenicity determinants was examined.

Results

Out of ninety strains isolated from children with deciduous teeth fifty three were classified as S. mutans species. PDH activity was higher (21.69 U/mg on average) in the experimental group compared to the control group (5.74 U/mg on average) (P <0.001). Moreover, it was demonstrated that biotype I, established basing on the biochemical characterization of the strain, was predominant (58.5%) in oral cavity streptococcosis. Its dominance was determined by higher PDH activity compared to biotypes II and III (P = 0.0019).

Conclusions

The usefulness of biotyping in the determination of Streptococcus mutans pathogenicity determinants was demonstrated. The obtained results allow for better differentiation of S. mutans species and thus may contribute to recognition of pathogenic bacteria transmission mechanisms and facilitate treatment.

Effects of 2 bracket and ligation types on plaque retention: a quantitative microbiologic analysis with real-time polymerase chain reaction

INTRODUCTION

The aim of this study was to evaluate the effects of self-ligating brackets and conventional brackets ligated with stainless steel ligatures on dental plaque retention and microbial flora.

METHODS

Twenty boys (mean age, 14.2 ± 1.5 years) underwent bonding with self-ligating bracket systems and conventional standard edgewise bracket systems ligated with stainless steel ligatures with a split-mouth design. Clinical measurements, including plaque index, probing pocket depth, and bleeding on probing, were obtained before bonding, 1 week after bonding, and 3 months after bonding. Supragingival plaque samples were obtained at baseline and 3 months after bonding for the detection of bacteria. A quantitative analysis for Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Lactobacillus acidophilus was performed using real-time polymerase chain reaction. The Mann-Whitney U test and the Hotelling T(2) multivariate test were used for statistical comparisons of the groups.

RESULTS

The numbers of S mutans, S sobrinus, L casei, and L acidophilus were not statistically different between self-ligating brackets and conventional brackets ligated with stainless steel ligatures (P >0.05). The 2 archwire ligation techniques showed no statistically significant differences in plaque index, bleeding on probing, and probing pocket depth values of the bonded teeth (P >0.05). All clinical parameters and the numbers of all microorganisms showed statistically significant increases from baseline to 3 months after bonding in both groups (P <0.001).

CONCLUSIONS

Self-ligating brackets and conventional brackets ligated with stainless steel ligatures do not differ with regard to dental plaque retention.

Streptococcus mutans and Streptococcus sobrinus detection by Polymerase Chain Reaction and their relation to dental caries in 12 and 15 year-old schoolchildren in Valencia (Spain)

A cross-sectional study was carried out to determine the prevalence of Streptococcus mutans and Streptococcus sobrinus and the association of the two in a random sample (n=614) of the child population of the region of Valencia (Spain). Saliva samples were analyzed by the quantitative polymerase chain reaction (PCR) method to study the relation of these bacteria to caries prevalence and the DMFT index. The prevalence of S. mutans was 35.4% at age 12 and 22.9% at age 15, that of S. sobrinus 18.9% and 8.4% and that of the S. mutans-S. sobrinus association 18.2% and 6.8% respectively. At both 12 and 15 years of age, the caries prevalence rates were lower in the Streptococcus-free group of children (37.6% and 48.5% respectively) and higher in the S.mutans-only group (67.3% and 74.0%). At the age of 12, the DMFT index was significantly higher in the mutans-only carriers (2.1) than in the Streptococcus-free and S. mutans-S. sobrinus association groups (both 0.9). At the age of 15, the DMFT index was significantly higher in the S. mutans-S. sobrinus association (3.71) and mutans-only (3.1) carrier groups than in the Streptococcus-free group (1.4). Determination of S. mutans and S. sobrinus by real-time quantitative PCR can provide valuable information for caries risk assessment in epidemiological studies.

Key words:Streptococcus mutans, Streptococcus sobrinus, polymerase chain reaction, dental caries, cross-sectional studies.

Comparative analysis of colony counts of different species of oral streptococci in saliva of dentulous, edentulous and in those wearing partial and complete dentures

OBJECTIVES

To study and compare the number of colony forming units of Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus mitis and Streptococcus milleri in dentulous, edentulous and in those wearing partial and complete dentures by using semi-quantitative culture method of saliva samples with calibrated standard loop.

MATERIALS

Sterile specimen collection bottles, Mitis salivarius agar plates, Standard loop, Candle jar, Incubator, Colony counter.

METHODOLOGY

Study population consisted of 100 subjects with 25 in each group, with an age range of 40 to 80 years, who were attending the Department of Community Dentistry and Prosthodontics at MNR Dental College, Sangareddy, Hyderabad. Unstimulated saliva samples were collected from patients and inoculated on to Mitis salivarius agar plates using calibrated standard loop. The plates were then incubated anaerobically at 37°C for 24 hours and left at room temperature for further 24 hours. Using a colony counter, the number of colonies of each species was counted.

RESULTS

Streptococcus mutans and Streptococcus mitis predominates in the dentulous group, Streptococcus sanguis in complete denture group, Streptococcus salivarius in edentulous group and Streptococcus milleri in removable partial denture group.

CONCLUSION

The results of our study are in accordance with the previous studies, which have sought to differentiate different groups of mutans streptococci using a simple calibrated standard loop.

Recovery of mutans streptococci on MSB, SB-20 and SB-20M agar media

OBJECTIVE

The recovery of mutans streptococci in saliva and dental biofilm samples depends, in part, on the culture medium used. In this study, we compared (i) the culture media Sucrose-Bacitracin agar (SB-20), Modified SB-20 (SB-20M) and Mitis Salivarius Bacitracin agar (MSB) in the count of colony forming units (cfu) of mutans streptococci and (ii) in the morphological and biochemical differentiation between Streptococcus mutans and Streptococcus sobrinus.

DESIGN

Samples of non-stimulated saliva from 20 children were plated on SB-20, SB-20M and MSB, and incubated in microaerophilia at 37°C for 72h. Identification of microorganisms was based on analysis of colony morphology under stereomicroscopy. The biochemical identification of colonies was done by biochemical tests using sugar fermentation, resistance to bacitracin and hydrogen peroxide production.

RESULTS

There was no significant difference (p>0.05) in the number of cfu of mutans streptococci recovered on SB-20 and SB-20M agar. Comparing the media, SB-20 and SB-20M yielded a larger number of mutans streptococci colonies (p<0.05) and were more effective than MSB in the identification of S. sobrinus (p<0.05), but not of S. mutans (p>0.05).

CONCLUSION

There was no significant difference between SB-20 and SB-20M culture media in the count of mutans streptococci, demonstrating that the replacement of sucrose by coarse granular cane sugar did not alter the efficacy of the medium. Compared with MSB, SB-20 and SB-20M allowed counting a larger number of mutans streptococci colonies and a more effective morphological identification of S. sobrinus.

Beyond Streptococcus mutans: dental caries onset linked to multiple species by 16S rRNA community analysis

Dental caries in very young children may be severe, result in serious infection, and require general anesthesia for treatment. Dental caries results from a shift within the biofilm community specific to the tooth surface, and acidogenic species are responsible for caries. Streptococcus mutans, the most common acid producer in caries, is not always present and occurs as part of a complex microbial community. Understanding the degree to which multiple acidogenic species provide functional redundancy and resilience to caries-associated communities will be important for developing biologic interventions. In addition, microbial community interactions in health and caries pathogenesis are not well understood. The purpose of this study was to investigate bacterial community profiles associated with the onset of caries in the primary dentition. In a combination cross-sectional and longitudinal design, bacterial community profiles at progressive stages of caries and over time were examined and compared to those of health. 16S rRNA gene sequencing was used for bacterial community analysis. Streptococcus mutans was the dominant species in many, but not all, subjects with caries. Elevated levels of S. salivarius, S. sobrinus, and S. parasanguinis were also associated with caries, especially in subjects with no or low levels of S. mutans, suggesting these species are alternative pathogens, and that multiple species may need to be targeted for interventions. Veillonella, which metabolizes lactate, was associated with caries and was highly correlated with total acid producing species. Among children without previous history of caries, Veillonella, but not S. mutans or other acid-producing species, predicted future caries. Bacterial community diversity was reduced in caries as compared to health, as many species appeared to occur at lower levels or be lost as caries advanced, including the Streptococcus mitis group, Neisseria, and Streptococcus sanguinis. This may have implications for bacterial community resilience and the restoration of oral health.

Caries prevalence associated with Streptococcus mutans and Streptococcus sobrinus in Japanese schoolchildren

BACKGROUND

Streptococcus mutans and Streptococcus sobrinus are known to be associated with dental caries in humans.

AIM

We used a polymerase chain reaction method to detect S. mutans and S. sobrinus in 128 Japanese schoolchildren and then compared their presence with the dental caries experience.

DESIGN

Plaque samples were collected from all erupted tooth sites with a sterile toothbrush, and dental examinations were performed to determine the numbers of decayed and filled teeth in primary (dft) and permanent (DFT) dentition using the WHO caries diagnostic criteria. Fisher's PLSD test was employed to compare caries scores between combinations of the detected bacteria.

RESULTS

Streptococcus mutans and S. sobrinus were present in 38.3% and 68.0%, respectively, whereas 14.8% were positive for S. mutans alone, 44.5% for S. sobrinus alone, and 23.5% for both S. mutans and S. sobrinus, with 17.2% negative for both. The DFT, dft, and total (DFT + dft) scores for subjects positive for both S. mutans and S. sobrinus were significantly higher than those positive for S. mutans alone (P < 0.05, in triplicate).

CONCLUSION

These results suggest that schoolchildren harbouring both S. mutans and S. sobrinus have a significant higher dental caries experience in both permanent and primary teeth as compared to those with S. mutans alone.