Influence of preventive dental treatment on mutans streptococci counts in patients undergoing head and neck radiotherapy

The aim of this study was to evaluate the influence of chlorhexidine gluconate, sodium fluoride and sodium iodine on mutans streptococci counts in saliva of irradiated patients. Forty-five patients were separated into three experimental groups and received chlorhexidine (0.12%), sodium fluoride (0.5%) or sodium iodine (2%), which were used daily during radiotherapy and for 6 months after the conclusion of the treatment. In addition, a fourth group, composed by 15 additional oncologic patients, who did not receive the mouthwash or initial dental treatment, constituted the control group. Clinical evaluations were performed in the first visit to dental clinic, after initial dental treatment, immediately before radiotherapy, after radiotherapy and 30, 60, 90 days and 6 months after the conclusion of radiotherapy. After clinical examinations, samples of saliva were inoculated on SB20 selective agar and incubated under anaerobiosis, at 37oC for 48 h. Total mutans streptococci counts were also evaluated by using real-time PCR, through TaqMan system, with specific primers and probes for S. mutans and S. sobrinus. All preventive protocols were able to reduce significantly mutans streptococci counts, but chlorhexidine gluconate was the most effective, and induced a significant amelioration of radiotherapy side effects, such as mucositis and candidosis. These results highlights the importance of the initial dental treatment for patients who will be subjected to radiotherapy for head and neck cancer treatment.

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 72 h. 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. © 2012 Elsevier Ltd.

The effect of chlorhexidine on plaque index and mutans streptococci in orthodontic patients: A pilot study

Aim: The purpose of this study was to assess chlorhexidine effects on plaque index and salivary levels of mutans streptococci (MS) when used as the immersion solution for removable orthodontic appliances and added to their acrylic resin composition. Methods: Forty-five patients (6 to 12 years old) were randomly assigned into three groups with 15 patients each. Group I (control)—without orthodontic appliances disinfection; Group II—removable orthodontic appliances which had been immersed in 0.12% chlorhexidine digluconate overnight (8 hours), and Group III—orthodontic appliances in which 0.12% chlorhexidine digluconate solution had been incorporated into their resin composition. Saliva was collected for quantification of MS and evaluation of plaque index was performed before and after installation of orthodontic appliance at 0, 2, 4, 6, 8, and 10 weeks. Data were analyzed by using analysis of variance. Results: Number of MS colonies in saliva and plaque index showed no statistically differences among groups at the different periods (p > 0.05). Conclusions: It could be concluded that chlorhexidine incorporation into the acrylic resin of removable orthodontic appliances at 0.12% concentration and immersion of the appliance into 0.12% chlorhexidine solution were not effective in reducing plaque index and the number of MS in saliva.

Are mutans streptococci detected in preschool children a reliable predictive factor for dental caries risk? A systematic review

Research suggests that mutans streptococci play an important role in cariogenesis in children but the usefulness of bacterial testing in risk assessment is unknown. Our objective was to summarize the literature assessing the association of mutans streptococci and dental caries in preschool children, (Pre)Medline (1966-2003), Embase (1980-2003), the Cochrane Register of Controlled Trials (2003, issue 3), and reference lists of included studies were searched. All abstracts found by the electronic searches (n = 981) were independently scrutinized by 2 reviewers. Minimal requirements for inclusion were assessment of preschool children without caries at baseline, reporting of mutans streptococci present in saliva or plaque at baseline and assessment of caries presence after a minimum of 6 months of follow-up. Participants' details, test methods, methodological characteristics and findings were extracted by one reviewer and cross-checked by another. Homogeneity was tested using chi2 tests. Results of plaque and saliva testing were pooled separately using a fixed effects model. Methodological quality of reports was low. Out of 9 studies included, data from 3 reports on plaque test assessment alone (n = 300) and from 4 reports on saliva test assessment alone (n = 451) were available for pooled analysis. The pooled risk ratio (95% CI) was 3.85 (2.48-5.96) in studies using plaque tests and 2.11 (1.47-3.02) in those using saliva testing. Presence of mutans streptococci, both in plaque or saliva of young caries-free children, appears to be associated with a considerable increase in caries risk. Lack of adjustment for potential confounders in the original studies, however, limits the extent to which interpretations for practice can be made.

A longitudinal controlled study of factors associated with mutans streptococci infection and caries lesion initiation in children 21 to 72 months old

Purpose: The purpose of this longitudinal study was to determine factors associated with mutans streptococci (MS) infection and development of caries lesions in a group of children 21 to 72 months old. Methods: The 63 caries-free children, recruited since birth, were divided into: (1) a study group of 24 children who were colonized with MS; and (2) a control group of 39 children without MS. The children were recalled every 3 months for approximately 24 months, and their social, medical, and dental histories were updated. At each recall, the teeth were checked for presence or absence of plaque, enamel hypoplasia, and caries lesions, and their MS status was assessed using a commercial test kit. Results: MS infection was associated with: (1) visible plaque (P < .01); (2) enamel hypoplasia (P < .05); (3) commencement of tooth-brushing after 12 months of age (P < .05); (4) lack of parental assistance with tooth-brushing (P < .025); and (5) increased hours of child care/school (P < .05). Four children (20%) were colonized at an age range of 21 to 36 months, 9 (45%) at 37 to 48 months, and 7 (35%) at 49 to 72 months (P < .001). Eight children who developed caries lesions: (1) had more hypoplastic teeth (P < .001); (2) ate sugar-containing snacks (P < .05); and (3) did not brush regularly with chlorhexidine gel (P < .01) compared to those who remained free of caries lesions. Conclusions: Lack of oral hygiene, consumption of sugar-containing snacks, and enamel hypoplasia are significant factors for both MS infection and caries lesion initiation.

Morphological differentiation between S. mutans and S. sobrinus on modified SB-20 culture medium

Due to the major role of Streptococcus mutans and Streptococcus sobrinus in the etiology of dental caries, it is important to use culture media that allow for differentiating these bacterial species. The aim of this study was to evaluate the suitability of a modified SB-20 culture medium (SB-20M) for the isolation and morphological differentiation of S. mutans and S. sobrinus, compared to biochemical identification (biotyping). Saliva samples were collected using the spatula method from 145 children, seeded on plates containing the SB-20M, in which sucrose was replaced by coarse granular cane sugar, and incubated in microaerophilia at 37 degrees C during 72 h. Identification of the microorganisms was performed under stereomicroscopy based on colony morphology of 4904 colonies. The morphological identification was examined by biochemical tests of 94 randomly selected colonies with the macroscopic characteristic of S. mutans and S. sobrinus using sugar fermentation, resistance to bacitracin and production of hydrogen peroxide. There was no statistically significant difference (p> 0.05) between morphological identification in the SB-20M medium and biochemical identification (biotyping). Biotyping confirmed that S. mutans and S. sobrinus colonies were correctly characterized in the SB-20M in 95.8% and 95.5% of the cases, respectively. Of the mutans streptococci detected in the children 98% were S. mutans and 2% S. sobrinus. The SB-20M medium is reliable for detection and direct morphological identification of S. mutans and S. sobrinus. (C) 2010 Elsevier GmbH. All rights reserved.

Longitudinal study of the influence of removable partial denture and chemical control on the levels of Streptococcus mutans in saliva

Some studies have evaluated the salivary levels of mutans streptococci (MS) in removable partial denture (RPD) users. Saliva samples (2.0 mL) were obtained from 31 patients in six periods: (T0): immediately before installation of RPD; (T8): 8 days after T0; (T48): 48 days after T0; (T92): 92 days after T0; (T140): 140 days after T0 and (T189): 189 days after T0. The samples were vortexed and serially diluted from 10(-1) to 10(-6) in 0.05 m phosphate buffer (pH 7.4). From each dilution, 0.025 mL was plated on Mitis Salivarius Bacitracin (MSB). The plates were incubated in 5% CO2 at 37 degreesC for 72 h. There was an increase (t -test, P < 0.05) in the number of MS between periods T0 and T48 (mean/s.d., CFU mL(-1) of saliva): T0: 2.26/4.43 x 10(6) and T48: 0.47/1.48 x 10(8) . After this, intensive treatment with CHX was accomplished in 29 patients. Saliva samples were obtained after treatment in four periods: (T24 h): 24 h after T0; (T14): 14 days after T24 h; (T28): 28 days after T24 h, and (T63): 63 days after T24 h. The number of MS in saliva did not decrease (t -test, P > 0.05). A new CHX formulation was applied in 15 patients. Saliva samples were obtained in periods: (T0): before new CHX application; (T24 h): 24 h after T0 and (T82): 82 days after T0. The new CHX reduced MS levels in saliva: (mean/s.d., CFU mL(-1) of saliva): T0: 6.64/8.47 x 10(6) and T24 h: 3.2/4.27 x 10(5) (sign rank, P < 0.05). In conclusion, there was a significant increase in the number of MS in saliva after the installation of RPD. The intensive treatment with a properly formulated CHX was effective in the reduction of MS, between 24 h and 82 days after its application.

Genetic polymorphism of Streptococcus mutans in Brazilian family members

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caries risk tests and salivary levels of immunoglobulins to Streptococcus mutans and Candida albicans in mouthbreathing syndrome patients

The aim of this study was to compare microbiological and salivary variables possibly related to caries risk in treated and untreated mouthbreathing syndrome (MBS) children and control children. Thirty control children, 30 mouthbreathers and 25 treated mouthbreathers were studied for the numbers of lactobacilli, mutans streptococci and yeasts in their saliva. Snyder's test, salivary flow and buffering capacity were also evaluated. Levels of immunoglobulins to Candida albicans and Streptococcus mutans in the saliva were quantified using ELISA. Considering the results obtained for the microbiological and salivary caries risk tests, no significant differences were observed among the proportions of patients with small/negative and high/moderate caries risk in the studied groups. The level of IgG to S. mutans was significantly higher in the treated MBS group in relation to MBS patients. on the other hand, the median anti-S. mutans IgM level was lower in the treated MBS patients than in the other groups. For the studied anti-Candida immunoglobulins, IgM level was significantly lower in the treated MBS group than in the other groups. No differences were observed for anti-S. mutans and anti-Candida IgA levels among the groups. The findings suggest that mouthbreathing cannot be considered a risk factor for dental caries. Copyright (C) 2003 S. KargerAG, Basel.

Reprodutibilidade de um teste microbiológico para estreptococos do grupo mutans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque samples from Brazilian preschool children by polymerase chain reaction

The purposes of this study were to detect S. mutans and S. sobrinus by polymerase chain reaction (PCR) amplification, and to relate their presence to the incidence of dental caries in 42 Brazilian preschool children. Dental plaque samples were collected from the cervical margin of all erupted teeth of 5-6 years old children with primary dentition, using a sterile explorer. Examination of the dmft (decayed, missing, filled teeth) index, performed following the World Health Organization (WHO) caries diagnostic criteria, showed a 2.71 score. Prevalence of S. mutans and S. sobrinus was respectively, of 85.7% and 14.3%; no dental plaque sample was either positive or negative for both bacterial species. Children harboring either S. mutans or S. sobrinus presented the same caries prevalence. PCR showed good discriminative ability for differentiation between these species, and suggested that it is a technique suitable for epidemiological studies on mutans streptococci.

Genetic polymorphism of Streptococcus mutans strains associated with incomplete caries removal

Aim: Despite the antibacterial properties of dental materials, the survival of residual bacteria under restorations has been demonstrated after incomplete caries removal. The aim of this study was to evaluate the genetic polymorphism of Streptococcus mutans strains isolated from deep dentinal lesions before and three months after incomplete caries removal. Methods: Samples of carious dentin were collected from 33 primary and/or permanent molars before and after indirect pulp treatment and processed for microbiological isolation of mutans streptococci (MS). After three months of the dental treatment, positive cultures for MS were detected in only ten of these teeth. DNA of MS isolates were obtained and subjected to polymerase chain reaction (PCR) for identification of S mutans. The arbitrary primed-PCR method (primer OPA-13) was used to detect the genetic polymorphism of S. mutans strains. Results: Identical or highly related S. mutans genotypes were observed in each tooth, regardless of the collect. Considering each tooth separately, a maximum of nine genotypic patterns were found in each tooth from all the collects. In addition, at least one genotypic pattern was repeated in the three collects. Genetic diversity was observed among the S. mutans isolates, obtained from different teeth after three months of the dental treatment. Conclusions: The persistence of identical genotypic patterns and the genetic similarity among the isolates, from the same tooth in distinct collects, showed the resistance of some S. mutans strains after incomplete caries removal treatment.

Contaminação cruzada em escovas dentais por Streptococcus mutans

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da presença de lesões de cárie dentária, biofilme bacteriano visível e análise microbiológica de Streptococcus grupo mutans em crianças de 12 a 48 meses de idade, portadoras e não portadoras da Síndrome de Down

Pós-graduação em Odontologia - FOAR