Checkerboard DNA-DNA Hybridization Research Articles

Microbial profile in different orthodontic appliances by checkerboard DNA-DNA hybridization: An in-vivo study

The design of the orthodontic bracket orappliance is 1 of the most important factors for creating retentive areas for biofilm formation. In orthodontics, this would be the first study to compare the microbial level changes in 3 different types of orthodontic appliances using checkerboard DNA-DNA hybridization technique. The purpose of this study was to evaluate and compare the extent of appearance of orange and red microbial complexes in patients undergoing orthodontic treatment using aligners, conventional metallic fixed labial appliances, and lingual fixed appliances. A total of 60 patients, of which 20 patients were undergoing treatment with aligners, 20 patients with labial fixed appliances, and 20 patients with lingual fixed appliances, were included in our study. After 30days, debonded brackets and rinsed aligners were stored and processed for analysis with checkerboard DNA-DNA hybridization. Most bacterial species showed moderate counts, with the exception of Treponema denticola, which showed a higher count in all 3 types of appliances. Fusobacterium nucleatum, Porphyromonas gingivalis, and T denticola were present in a higher percentage in the lingual appliance. Fusobacterium periodontium and Prevotella intermedia were present in a higher percentage in the labial fixed appliance. Campylobacter rectus, Tannerella forsythia, and Prevotella melaninogenica counts were moderate in all 3 appliances, with the first 2 microbes showing slightly higher counts in aligners. The association between all the microorganisms were statistically insignificant, with the exception of Fnucleatum, which showed a strong statistically significant association in all 3 types of appliances. The microbial contamination in metallic brackets was higher than that of aligners, when used for a month. Lingual fixed appliances showed more microbial contamination than labial fixed appliances followed by aligners.

Titanium particles and ions favor dysbiosis in oral biofilms.

To evaluate the effect of titanium (Ti) particles and ions on oral biofilm growth and composition. Particles and ions of Ti released from dental implants can trigger unfavorable biological responses in human cells. However, their effect on oral biofilms composition has not been tested. In this blind in situ study, volunteers wore a palatal appliance containing Ti disks for 7days to allow biofilm formation. Disks were then collected and biofilms were treated, in vitro, with Ti particles (0.75% and 1%), ions (10 and 20ppm), or a combination of both (1% particles+20ppm ions). Biofilms exposed only to medium was used as control group. After 24hours, biofilms were collected and analyzed by checkerboard DNA-DNA hybridization. Direct effects of Ti particles and ions on biofilm/cellular morphology were evaluated by transmission electron microscopy (TEM). Ti particles affected biofilm composition, increasing population of four bacterial species (P<.05), while Ti ions showed higher levels of putative pathogens from the orange complex with reduction in species from the yellow complex (P<.05), compared with control. The combination of particles+ions increased green complex and reduced yellow complex proportions (P<.05). TEM showed clusters of particles agglomerated in extracellular environment, while Ti ions were precipitated in both extracellular and intracellular sites. Ti products, especially Ti ions, have the potential to change the microbiological composition of biofilms formed on Ti surfaces. Therefore, the presence of Ti products around dental implants may contribute to microbial dysbiosis and peri-implantitis.

Putative periodontal bacteria in clinically healthy and diseased sites of periodontitis patients

Aim: The aim of this study was to compare the microbial profile of subgingival sites in Periodontitis (Pd) patients and healthy ones. Methods: Eighteen patients with Pd and 18 gender-matched healthy controls were selected. Subgingival samples were collected from three types of sites: 1) healthy site of healthy subjects (probing pocket depth (PPD) ≤ 3mm, CG), 2) healthy site of Pd patients (PPD ≤ 3mm, PG-C) and 3) diseased site (PPD &gt; 3mm) of the same Pd patients (PG-T). All sites were subjected to microbial analysis for the detection of 40 bacterial species by the "Checkerboard DNA-DNA hybridization" technique. Results: It was observed a great diversity of bacteria in all patients evaluated. The sites from the Pd groups (PG-T and PG-C) showed a higher overall count of the studied bacteria than those of the CG group, especially from Green, Orange, and Red complexes. Also, PG-T showed a higher prevalence of Red complex bacteria than CG. Individual pathogens, such as Porphyromonas gingivalis, Treponema denticola and Treponema socranskii were detected in higher levels and/or prevalence in Pd than in control patients. However, it was not observed any difference between PG-T and PG-C. Conclusion: Pd patients showed higher prevalence and counts of some putative periodontal bacteria, especially from the red complex, than control ones, regardless of the severity of their sites.

Subgingival microbial profile of women with breast cancer: a cross-sectional study

BackgroundSome prospective studies have observed associations between periodontal disease and breast cancer. Therefore, the aim of the present study was to investigate the composition of the subgingival biofilm of women diagnosed with breast cancer, who also presented with chronic periodontitis.MethodsAll subjects underwent clinical and microbiological assessment. Subgingival biofilm samples were taken from at least three sites of 44 women who had breast cancer. The mean levels and proportions of 40 bacterial species were determined by checkerboard DNA-DNA hybridization. Spearman correlation was used to assess possible associations between the mean levels of bacterial species and clinical conditions.ResultsThe five species found at the highest levels were Prevotella nigrescens, Actinomyces gerencseriae, Neisseria mucosa, Porphyromonas gingivalis and Tannerella forsythia. The species detected in the lowest counts were Propionibacterium acnes, Streptococcus constellatus, Streptococcus intermedius, Eubacterium saburreum and Streptococcus anginosus. No significant association between levels and proportion of bacterial species and clinical parameters were found.ConclusionIn conclusion, the results of the present study found no direct association between the subgingival microbiota and breast cancer and an indirect pathway should be addressed in further studies.Trial registrationRetrospectively registered.

Bacterial Profile and Radiographic Analysis Around Osseointegrated Implants With Morse Taper and External Hexagon Connections: Split-Mouth Model.

The aim of this clinical study was to evaluate bacterial colonization, marginal bone loss, and optical alveolar density in implants with Morse taper (MT) and external hexagon (EH) connections. Thirty-five implants were installed in 7 patients (mean age: 65.8 ± 6.7 years). Implants were divided into 2 groups, according to platform design: G1 - MT, installed 2mm infra-osseous and G2 - EH, positioned according to Branemark protocol. Patients were evaluated at baseline (T0), 21 days (T1), 3 months (T2), 6 months (T3), and 12 months (T4) after installations. Bone loss and alveolar density were evaluated by standardized periapical radiographs and bacterial profile with checkerboard DNA-DNA hybridization. Statistical analyses were performed using SPSS 23.0. To present the results, boxplots and a line graph of mean were used. P-values ≤ .05 were statistically significant. After 3 months, alveolar bone loss was significantly higher in the G2 (T2-T0: P = .006; T3-T0: P = .003; and T4-T0: P = .005). No significant differences between G1 and G2 groups were observed for optical alveolar density. Microbiological analysis showed similar profiles between studied groups; however, there were significantly higher counts of Tannerella forsythia (P = .048), Campylobacter showae (P = .038), and Actinomyces naeslundii (P = .027) in G1 after 12 months. Based on the results of this study, it can be concluded that there was less peri-implant bone loss in MT compared to EH connections, but microbiological profile did not seem to influence bone changes.

Microbial Profile and Endotoxin Levels in Primary Periodontal Lesions with Secondary Endodontic Involvement.

This study was carried out to investigate the microbial profile and endotoxin levels of endodontic-periodontal lesions of periodontal origin. Periodontal and endodontic samples were taken from periodontal pockets and necrotic root canals of 10 teeth with endodontic-periodontal lesions. Evidencing of 40 different bacterial species were determined in each endodontic and periodontal sample using the checkerboard DNA-DNA hybridization method and Kinetic chromogenic LAL assay was used for quantification of endotoxins. Fisher's exact test correlated the bacterial species with the endodontic or periodontal microbiota. The endotoxin levels (EU/mL) found in samples of the root canal and periodontal pocket were compared by the Wilcoxon test (p<0.05). Bacteria and LPS units were found in 100% of the endodontic and periodontal samples. The species E. faecium, P. acnes, G. morbillorum, C. sputigena and L. buccalis were strongly correlated with the endodontic microbiota and P. nigrescens with the periodontal microbiota. P. intermedia, P. endodontalis and V. parvula were more prevalent in both endodontic and periodontal microbiots. The endotoxin levels in the periodontal pocket (89600 EU/mL) were significantly higher than in the root canal (2310 EU/mL). It was concluded that the microbiota present in the periodontal and endodontic tissues is similar, with a higher prevalence of species of the orange complex and a higher level of endotoxin in the periodontal pockets.

Iodoform and silver-coated abutments preventing bacterial leakage through the implant-abutment interfaces: In vitro analysis using molecular-based method

ObjectivesThe aim of this in vitro study was to evaluate the effectiveness of an iodoform paste and silver-coated abutments in preventing the microbial colonization and leakage through the implant-abutment interface of morse taper and internal hexagon implants. Material and methodsSeventy-two implants with morse taper (n = 36) or internal hexagon connections (n = 36) were investigated. Implants were treated with iodoform paste (n = 12), silver-coated abutments (n = 12), or control (n = 12). After saliva incubation, Checkerboard DNA-DNA hybridization was used to identify and quantify up to 43 microbial species colonizing the inner parts of the implants. ANOVA-Type and Wald-Type analyses of variance were used to investigate the relative effects and their interaction. Friedman- Conover test adjusted by Benjamini-Hockberg FDR were performed for pairwise multiple comparisons. Significance was set as p < 0.05. ResultsAnalyses of variance indicate a significant interaction between connections, antimicrobial treatments, and species. The frequency of contamination was reduced in the implants submitted to the antimicrobial treatments. Iodoform and silver-coated abutments significantly reduced the total microbial counts in the internal hexagon implants. The lower microbial counts were recorded for morse taper implants with silver-coated abutments. ConclusionsIodoform paste and silver-coated abutments have influenced the microbial leakage through the implant-abutment interface, by reducing both frequency of contamination and microbial levels. Treatments were not effective in reducing the counts of the target species.

Microbial species associated with dental caries found in saliva and in situ after use of self-ligating and conventional brackets.

Objectives Enamel demineralization is among the main topics of interest in the orthodontic field. Self-ligating brackets have been regarded as advantageous in this aspect. The aim of this study was to evaluate the break homeostasis in the oral environment and the levels of microorganisms associated with dental caries among the different types of brackets.Material and Methods Twenty patients received two self-ligating brackets: In-Ovation®R, SmartClipTM, and one conventional GeminiTM. Saliva was collected before bonding (S0), 30 (S1) and 60 (S2) days after bonding. One sample of each bracket was removed at 30 and 60 days for the in situ analysis. Checkerboard DNA-DNA Hybridization was employed to evaluate the levels of microbial species as-sociated with dental caries. Data were evaluated by nonparametric Friedman and Wilcoxon tests at 5% significance level.Results The salivary levels of L. casei (p=0.033), S. sobrinus (p=0.011), and S. sanguinis (p=0.004) increased in S1. The in situ analyses showed alteration in S. mutans (p=0.047), whose highest levels were observed to the In-Ovation®R.Conclusions The orthodontic appliances break the salivary homeostasis of microorganisms involved in dental caries. The contamination pattern was different between self-ligating and conventional brackets. The In-Ovation®R presented worse performance considering the levels of cariogenic bacterial species.

Multiple sessions of antimicrobial photodynamic therapy associated with surgical periodontal treatment in patients with chronic periodontitis.

This double-blind, randomized, controlled clinical trial assessed the efficacy of multiple sessions of antimicrobial photodynamic therapy (aPDT) as an adjunct to surgical periodontal treatment (ST) in patients with severe chronic periodontitis (SCP). Sixteen patients with SCP were treated with aPDT+ST (test group, TG) or ST only (control group, CG), in a split-mouth design. aPDT was applied at 0, 2, 7, and 14 postoperative days only in TG. All patients were followed up for 90 days after surgery. The following clinical and microbiological parameters were assessed: clinical attachment level (CAL), probing depth (PD), gingival recession (GR), bleeding on probing (BOP), plaque index (PI), and count of 40 subgingival microbial species (checkerboard DNA-DNA hybridization). Data were collected at baseline (preintervention), at 60 days (30 days after the end of non-surgical therapy), and at 150 days (90 days after surgery). A significant reduction in PD was observed at 150 days for the TG, when compared with the CG (P˂0.05). CAL gain was significantly higher in the TG at 60 and 150 days (P˂0.05). Changes in the subgingival microbiota were similar between the groups (P˃0.05), but the TG revealed a larger number of bacteria associated with periodontal disease at the end of the experiment compared with the CG (P<0.05). Multiple sessions of aPDT as an adjunct to surgical periodontal treatment significantly improved clinical parameters at 90 postoperative days.

Microbiologic Analysis of Immediately Loaded Full-Arch Implant-Retained Prosthesis Protocol After 2 Years of Loading: A Retrospective Study.

The All-on-4 treatment concept has been shown to be an effective clinical procedure; however, to date, no studies have analyzed the subgingival microbiota present in these restorations. The purpose of this study was to evaluate the microbial profile of the subgingival biofilm around dental implants placed in the All-on-4 protocol and compare the microbial profile around axial and tilted implants. Fourteen subjects treated by the All-on-4 concept were evaluated clinically and microbiologically. Subgingival biofilm was collected from each patient, and the amount of 40 species of bacteria was assessed using the checkerboard DNA-DNA hybridization technique. The results for the indices of probing depth (PD), bleeding on probing, marginal bleeding, and visible plaque were 2.32 mm, 46%, 60%, and 57%, respectively. Tilted implants presented a significantly higher mean PD and Plaque Index compared with axial implants (P < .05). Fusobacterium nucleatum ssp vincentii, Veillonella parvula, and Fusobacterium nucleatum ssp polymorphum were found in higher levels; however, no difference in the microbial composition was observed between tilted and axial implants (P > .05). Tilted implants presented statistically higher mean levels for the orange complex in relation to the axial implants (P < .05). Despite the clinical success rate of the All-on-4 protocol, the subgingival biofilm of tilted implants presented a higher proportion for the orange complex pathogens in comparison to axial implants. These data could suggest that subjects with this modality of implant-supported restoration must be aware that they need a more rigorous maintenance protocol.

Clinical and microbiological effects of scaling and root planing, metronidazole and amoxicillin in the treatment of diabetic and non-diabetic subjects with periodontitis: A cohort study.

To evaluate if non-diabetic subjects with periodontitis respond better than subjects with type 2 diabetes to the treatment protocol of scaling and root planing (SRP), metronidazole (MTZ) and amoxicillin (AMX). Diabetic and nondiabetic subjects with severe periodontitis received SRP+MTZ (400mg/thrice a day [TID])+AMX (500mg/TID) for 14days. Subgingival biofilm samples were analyzed by checkerboard DNA-DNA hybridization for 40 bacterial species. Subjects were monitored at baseline, 3, 6 and 12months post-therapy. Twenty-nine type 2 diabetics and 29 non-diabetic subjects participated of this study. Of the non-diabetics and diabetics, 68.9% and 75.9%, respectively, reached the clinical endpoint for treatment (≤4 sites with probing depth [PD] ≥5mm) at 1year post-therapy (p>0.05). The diabetic group presented lower mean clinical attachment gain from baseline to 1year post-therapy and higher mean proportions of the red and orange complexes than the non-diabetic group (p<0.05). Non-diabetic subjects with severe periodontitis did not respond better than type 2 diabetic subjects to the treatment protocol of SRP+MTZ+AMX, both in terms of achieving the clinical endpoint for treatment and of PD improvement. Diabetic subjects exhibited a slightly worse microbiological response and showed a healing process more associated with gingival recession than the non-diabetics.

Orthodontic appliances did not increase risk of dental caries and periodontal disease under preventive protocol.

To assess periodontal parameters and microbial species levels after orthodontic appliance placement in patients who received oral hygiene instructions and who were monitored and motivated throughout the study. The Periodontal Index was recorded and saliva collection was performed before (T0) and 30 (T1), 60 (T2), and 90 (T3) days after orthodontic appliance placement in 15 patients (mean age 17.53 ± 8.0 years). Analysis was carried out using checkerboard DNA-DNA hybridization. Nonparametric statistical analysis was performed. The Periodontal Index did not change. The total amount of the purple and red complexes and Candida species showed a significant decrease from T2. The green, yellow, and orange complex showed a significant decrease at T3. The specific species analysis showed that Prevotella nigrescens, Pseudomonas putida, Fusobacterium periodonticum, Pseudomonas aeruginosa, Peptostreptococcus anaerobius, and Tanerella forsythia showed high incidence before bonding, and their levels decreased at T2 and T3. Only Porphyromonas gingivalis showed increased levels at T2 and displayed the highest level at T3. The Streptococcus group decreased their levels from T2 onward. A dynamic change in microbial levels was identified. The decrease in the levels of complexes present was only possible due to the mechanical method of oral hygiene implemented in this sample.

Effect of sucrose on biofilm formed in situ on titanium material.

Because sucrose may change the composition of biofilms formed on dental surfaces, the aim of this study was to evaluate in situ the effect of this dietary sugar on biofilm formation on titanium surface. In this blind, crossover, in situ study, 10 volunteers wore, in 3 phases of 7days each, a palatal appliance containing titanium specimens. In each phase, the specimens were treated extraorally with 20% sucrose solution at a frequency of 4 or 8times per day. As control, no treatment was rendered (0×). At the end of each phase, the biofilms were collected for biochemical analysis of biofilm wet weight (biomass), protein concentration, soluble (S-EPS), and insoluble (I-EPS) extracellular polysaccharides and intracellular polysaccharides (IPS), and for microbiologic analysis by checkerboard DNA-DNA hybridization (for levels and proportions of 40 bacterial species). Biochemical data were analyzed by linear regression and microbiological findings by Friedman and Dunn tests (α= .05). A positive significant linear relationship was found among sucrose exposure (0×, 4×, and 8×) and biomass, S-EPS, I-EPS and IPS (p< 0.05). The biofilms treated with sucrose (4× and/or 8×) presented higher mean total levels of the 40 bacterial species evaluated, higher proportions of red complex species and lower proportions of the host-compatible green complex species, in comparison with the control group (p< 0.05). The findings of the present study suggest that daily sucrose exposure has a harmful effect on the composition of biofilms formed on titanium surfaces.

The ideal time of systemic metronidazole and amoxicillin administration in the treatment of severe periodontitis: study protocol for a randomized controlled trial

BackgroundThe combination of systemic metronidazole (MTZ) and amoxicillin (AMX) with scaling and root planing (SRP) has shown to be an effective periodontal treatment. However, some essential issues associated with the use of these antibiotics remain unanswered, such as the ideal time of administration during the course of periodontal treatment. Although these agents are often prescribed after the healing phase of the SRP procedure, there is biological plausibility to support its use in conjunction with the mechanical treatment. However, to date, no placebo controlled randomized clinical trial (RCT) has directly compared these two protocols. Therefore, the aim of this RCT is to compare the clinical, microbiological and immunological effects of the adjunctive systemic MTZ + AMX administered in different phases of the treatment of severe periodontitis.MethodsSubjects with severe periodontitis (n = 180) are being randomly assigned into three groups (n = 60/group): (i) SRP-only (control group), SRP in combination with 400 mg MTZ + 500 mg AMX, starting (ii) at the first SRP session (active phase group), or (iii) after 3 months of its completion (healing phase group). All volunteers are receiving clinical and microbiological evaluation at baseline, 3, 6 and 12 months, and immunological assessment at baseline and 12 months post-therapy. Nine subgingival biofilm samples are being collected per subject and analyzed for counts and proportions of 40 bacterial species by checkerboard DNA-DNA hybridization, and six gingival crevicular fluid samples are being collected and analyzed for the levels of 20 chemokines by multiplex immunoassay. The primary outcome variable is the number of volunteers reaching the clinical endpoint for treatment (≤ 4 sites with probing depth ≥5 mm) at 1 year post-therapy. Differences in clinical, microbiological and immunological parameters among groups and over time will be evaluated using analysis of variance, analysis of covariance and the Chi-square and Tukey tests. Microbiological and immunological analyses will be performed using adjustments for multiple comparisons. Statistical significance will be set at 5%.Trial registrationClinicalTrials.gov, NCT02954393. Registered on 3 November 2016.

Support vector machine-based differentiation between aggressive and chronic periodontitis using microbial profiles

The existence of specific microbial profiles for different periodontal conditions is still a matter of debate. The aim of this study was to test the hypothesis that 40 bacterial species could be used to classify patients, utilising machine learning, into generalised chronic periodontitis (ChP), generalised aggressive periodontitis (AgP) and periodontal health (PH). Subgingival biofilm samples were collected from patients with AgP, ChP and PH and analysed for their content of 40 bacterial species using checkerboard DNA-DNA hybridisation. Two stages of machine learning were then performed. First of all, we tested whether there was a difference between the composition of bacterial communities in PH and in disease, and then we tested whether a difference existed in the composition of bacterial communities between ChP and AgP. The data were split in each analysis to 70% train and 30% test. A support vector machine (SVM) classifier was used with a linear kernel and a Box constraint of 1. The analysis was divided into two parts. Overall, 435 patients (3,915 samples) were included in the analysis (PH = 53; ChP = 308; AgP = 74). The variance of the healthy samples in all principal component analysis (PCA) directions was smaller than that of the periodontally diseased samples, suggesting that PH is characterised by a uniform bacterial composition and that the bacterial composition of periodontally diseased samples is much more diverse. The relative bacterial load could distinguish between AgP and ChP. An SVC classifier using a panel of 40 bacterial species was able to distinguish between PH, AgP in young individuals and ChP.

Efficacy of a single session protocol for endodontic treatment in primary teeth: in vivo study.

To determine the efficacy of a single session protocol (SSP) in the reduction of septic content of primary teeth root canals and identify the persistence of bacterial species associated with unsuccessful treatment. Primary teeth root canals (16) with pulp necrosis and peri-radicular lesions were treated. Samples were collected at baseline (T1), and after chemo-mechanical preparation, before filling (T2). Identification of the microorganisms was determined using checkerboard DNA-DNA hybridisation. Wilcoxon test was applied for comparison of mean number of species, proportion and mean count of each species between the evaluation times. Significant reductions were found in the mean number of bacteria species between T1 and T2 (p<0.05), but not for the reduction in proportion (p>0.05). There was a reduction (6.0-4.6) of the mean number of species associated with failure, without statistical significance. The SSP was capable of significantly reducing the septic content, even though, many of the bacteria associated with failure persisted at the time of root canal filling.

Immunologic burden links periodontitis to acute coronary syndrome

Background and aimsPeriodontitis, a common polymicrobial inflammatory disease in the tooth supporting tissues, is a risk factor for coronary artery disease. One of the proposed underlying mechanisms is the systemic immune response to periodontal infection. We studied how serum antibodies against seven periodontal pathogens and their subgingival levels associate with each other, periodontitis, and coronary artery disease. MethodsThe Parogene cohort included 505 Finnish patients (mean age 63 y) who underwent coronary angiography, and clinical and radiographic oral examinations. Coronary diagnosis was defined as no significant coronary artery disease (<50% stenosis, n = 152), stable coronary artery disease (≥50% stenosis, n = 184) and acute coronary syndrome (n = 169). Levels of subgingival Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, Tannerella forsythia, Campylobacter rectus, and Fusobacterium nucleatum were determined by checkerboard DNA-DNA hybridization. Serum antibody (IgA/IgG) levels were analyzed with enzyme-linked immunosorbent assay (ELISA). Aggregate IgA/IgG burdens were calculated by summing and standardizing the serum antibody levels. ResultsPatients with active periodontitis were characterized by higher levels of subgingival bacteria and corresponding IgA/IgG response. Quartiles 2–4 of serum IgA/IgG burden indicated higher risk for acute coronary syndrome (OR 1.84, 95%CI 1.01–3.35 for IgA; OR 1.87, 95%CI 1.01–3.46 for IgG) independently of established cardiovascular risk factors, body mass index, number of teeth, subgingival bacterial levels and periodontal diagnosis. ConclusionsOur findings support the hypothesis that the association between periodontitis and cardiovascular diseases is partly mediated by the immunologic response for periodontal pathogens.

Antimicrobial Efficacy of Materials Used for Sealing the Implant Abutment Screw Hole: An In Vitro Evaluation.

The aim of this in vitro study was to assess the antimicrobial efficacy of materials (gutta percha [GP], polytetrafluoroethylene [PTFE] tape, and vinyl polysiloxane [VP]) used for sealing the implant abutment screw hole (IASH). Sixty implants with a Morse cone connection were used. The implants were randomly divided into 3 groups (20 implants/group). In groups 1, 2, and 3, the IASH was sealed with GP, PTFE, and VP, respectively. Unstimulated whole saliva (UWS) was used as a contaminant medium for the incubation of the specimens. After 7 days of incubation, the specimens were opened under aseptic conditions, and the contents of the inner parts of the IASH were collected using sterile microbrushes. The occurrence of microbial leakage through the screw access channel interface was assessed with the checkerboard DNA-DNA hybridization method. P < 0.05 was considered statistically significant. Among samples in groups 1, 2, and 3, the UWS collected before incubation showed no statistically significant differences in relation to the prevalence of species investigated. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Candida albicans were isolated from group 1 than groups 2 and 3. The choice of material for sealing the IASH is entirely dependent on the operators' choice and experience.

Evaluation of the difference in caries experience in diabetic and non-diabetic children-A case control study.

AimTo evaluate the caries prevalence and related variables in Type 1 diabetic and non-diabetic children and among the diabetic children according to their metabolic status.MethodsSixty-eight diabetic and 136 non-diabetic children, matching by gender and age (4–14 years) were enrolled. The diabetic children were divided: a) 20 children in good metabolic control (Hb1ac≤7.5) and b) 48 children in bad metabolic control (Hb1ac>7.5). Dietary and oral hygiene habits were investigated. Caries status was registered using the International Caries Detection and Assessment System. Oral microflora was analysed using the checkerboard DNA-DNA hybridisation method. Plaque acidogenicity was recorded after a sucrose rinse.ResultsSugared beverage and snack intake was higher in diabetic group compared to non-diabetic group (p = 0.03 and p = 0.04, respectively) and in subjects in bad metabolic control (p = 0.03 and p<0.01, respectively). Oral hygiene habits were similar, except for the use of fluoridated adjuvants, higher in non-diabetic children (p = 0.04). No statistically significant differences were observed regarding caries figures, but a higher number of caries free subjects was found in diabetic subjects in good metabolic control (p<0.01). Significant difference for the main cariogenic bacteria was found between diabetic and non-diabetic subjects (p<0.05). The pH values showed statistically significant differences between diabetic and non-diabetic subjects and between diabetic subjects in good and bad metabolic control (p<0.01).ConclusionsDiabetic children in good metabolic control might even be considered at low caries risk, while those in bad metabolic control showed an oral environment prone to a high caries risk.

Colonization of oropharynx and lower respiratory tract in critical patients: Risk of ventilator-associated pneumonia

ObjectiveTo investigate the microbial diversity existing in oral cavity and respiratory tract samples (from mini-bronchoalveolar lavage (BAL), endotracheal aspirate, and orotracheal tube) of patients on mechanical ventilation by using the checkerboard DNA-DNA hybridisation. Also, the study aimed to evaluate whether the microbial profile in the oral cavity is found in respiratory tract samples, at different periods of mechanical ventilation time (12h, 48h, 96h) in attempt to identification of relationship between VAP (ventilator-associated pneumonia) and bacterial species studied. The last objective was to analyses correlation between blood cultures and VAP. DesignThe samples were collected from ten patients in intensive care unit with medical prescription of orotracheal intubation and mechanical ventilation. Clinical data were tabulated and blood cultures were performed according medical indication. For checkerboard samples collection, chosen sites were the dorsal side of the tongue and gingival sulcus at 12h, 48h, 96h, BAL, at 12h, endotracheal aspirate at 48 and 96h, and orotracheal tube at extubation time, when feasible. ResultsIt was possible to identify the presence of bacterial species in mouth and in the BAL/endotracheal aspirate. The data demonstrated an increase in the quantity of bacterial associated with prolonged use of mechanical ventilation (48 and 96h). ConclusionsBacterial species may migrate rapidly from mouth and upper airways during orotracheal intubation which contributes to the pathogenesis of VAP. There were associations between VAP and Enterococcus faecalis, Fusobacterium periodonticum, Gemella morbillorum, Neisseria mucosa, Propionibacterium acnes, Prevotella melaninogenica, Streptococcus oralis, Streptococcus sanguinis, Treponema denticola, Treponema socransckii, and Veillonella parvula.