Reginaldo Bruno Gonçalves

Impact of smoking on inflammation: overview of molecular mechanisms

BackgroundInflammation is a critical component of normal tissue repair, as well as being fundamental to the body’s defense against infection. Environmental factors, such as smoking, have been reported to modify the host response and hence modify inflammation progression, severity and outcome. Therefore, a comprehensive understanding of the molecular mechanisms by which smoking affects inflammation is vital for preventive and therapeutic strategies on a clinical level.AimThe purpose of the present article is to review the potential biological mechanisms by which smoking affects inflammation, emphasizing recent developments.ResultsSmoking is reported to effect a number of biological mediators of inflammation through its effect on immune-inflammatory cells, leading to an immunosuppressant state. Recent evidence strongly suggests that the molecular mechanisms behind the modulation of inflammation by smoking mainly involve the nuclear factor-kappa B (NF-kB) family, through the activation of both an inhibitor of IkB kinase (IKK)-dependent and -independent pathway. In addition to NF-kB activation, a number of transcriptional factors including GATA, PAX5 and Smad 3/4, have also been implicated.ConclusionMultiple mechanisms may be responsible for the association of smoking and inflammation, and the identification of potential therapeutic targets should guide future research.

Evaluation of the antibacterial activities of calcium hydroxide, chlorhexidine, and camphorated paramonochlorophenol as intracanal medicament. A clinical and laboratory study

The antibacterial activities of camphorated paramonochlorophenol, chlorhexidine, and calcium hydroxide were compared using a clinical and laboratory evaluation. In the clinical experiment, root canals that yielded positive cultures a week after complete chemomechanical preparation and camphorated paramonochlorophenol dressing were medicated with one of the three substances tested. Postmedication samples were taken from the canal 1 week later. In the laboratory experiment, the agar diffusion test was used to evaluate the inhibitory activity of the medicaments against bacteria commonly found in endodontic infections. The results of the clinical evaluation showed that all medicaments were effective in reducing or eliminating the endodontic microbiota, as demonstrated by the incidence of negative cultures. There was no statistically significant difference among the medicaments tested. In the laboratory evaluation, camphorated paramonochlorophenol showed the largest zones of bacterial inhibition against all bacterial strains tested.

Longitudinal Study of Transmission, Diversity, and Stability of Streptococcus mutans and Streptococcus sobrinus Genotypes in Brazilian Nursery Children

ABSTRACT The aim of this study was to perform a follow-up evaluation of the Streptococcus mutans and Streptococcus sobrinus colonization profile of childrens oral cavities, which included the pattern of vertical transmission from mother to child, genotypic diversity, and stability of the strains. The subjects were 16 mother-child pairs, who were monitored for 20 months. Samples of saliva, tongue dorsum, alveolar ridge mucosa, and dental plaque from the children were collected bimonthly. Saliva samples from the mothers were also collected. After isolation and identification, the arbitrarily primed PCR method was performed for the genotypic characterization of S. mutans (968 isolates) and S. sobrinus (111 isolates). At the time the strains were acquired, the children harbored one to four distinct genotypes of S. mutans and only one genotype of S. sobrinus. Although S. mutans prevalence and genotypic diversity were greater than those of S. sobrinus, the presence of matching genotypes of S. mutans and S. sobrinus was similar (in 81.25 and 83.33% of mother-child pairs, respectively), suggesting vertical transmission for both species. This longitudinal study showed an increase in genotypic diversity of S. mutans in the oral cavity during the follow-up period: most of the initially acquired genotypes persisted, normally those genotypes transmitted by the mother, and some were lost during follow-up; new strains were also acquired. In conclusion, S. mutans and S. sobrinus genotypes acquired from maternal or alternative sources may show effective persistence in the oral cavity and/or transitory detection in the childrens mouths, reflecting the continuous development of oral microbiota in children.

Antimicrobial potential of some plant extracts against Candida species

The increase in the resistance to antimicrobial drugs in use has attracted the attention of the scientific community, and medicinal plants have been extensively studied as alternative agents for the prevention of infections. The Candida genus yeast can become an opportunistic pathogen causing disease in immunosuppressive hosts. The purpose of this study was to evaluate dichloromethane and methanol extracts from Mentha piperita, Rosmarinus officinalis, Arrabidaea chica, Tabebuia avellanedae, Punica granatum and Syzygium cumini against Candida species through the analysis of Minimum Inhibitory Concentration (MIC). Results presented activity of these extracts against Candida species, especially the methanol extract.

Levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, inflammatory cytokines and species-specific immunoglobulin G in generalized aggressive and chronic periodontitis.

BACKGROUND AND OBJECTIVE Aggressive periodontitis pathogenesis still is not completely understood in the literature regarding the relationship between microbial and inflammatory aspects. So this study aimed to compare microbial and inflammatory patterns in the gingival crevicular fluid of generalized aggressive and chronic periodontitis patients. MATERIAL AND METHODS Forty aggressive and 28 chronic periodontitis patients were selected. Biofilm and gingival crevicular fluid were collected from a deep pocket (periodontal probing depth >7 mm) and a moderate pocket (periodontal probing depth = 5 mm) of each patient, and microbiological and immunoenzymatic assays were performed. Real-time PCR was used to determine quantities of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Enzyme-linked immunosorbent assay (ELISA) was employed to determine gingival crevicular fluid levels of interleukin-1beta, interferon-gamma, prostaglandin E(2) and interleukin-10. In addition, immunoglobulin G (IgG) levels against A. actinomycetemcomitans and P. gingivalis lipopolysaccharide were also determined by ELISA. Analysis of variance/Tukey test, Mann-Whitney U-test and the Pearson correlation test were used to determine differences and correlations between variables analysed (alpha = 5%). RESULTS Patients suffering from generalized aggressive periodontitis had their mouth colonized by higher amounts of A. actinomycetemcomitans and P. gingivalis than chronic periodontitis patients. Conversely, the gingival crevicular fluid levels of IgG against both pathogens were statistically inferior in aggressive periodontitis patients (p < 0.05). With regard to gingival crevicular fluid levels of cytokines, aggressive periodontitis patients presented reduced levels of interleukin-10 (p < 0.05). CONCLUSION In comparison to chronic periodontitis, generalized aggressive periodontitis patients have an imbalance in the host response, with reduced levels of interleukin-10 and IgG, and increased periodontal pathogens.

Subgingival biodiversity in subjects with uncontrolled type‐2 diabetes and chronic periodontitis

BACKGROUND AND OBJECTIVE There is a bidirectional relationship between periodontal disease and type-2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end-products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type-2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. MATERIAL AND METHODS Twelve subjects with uncontrolled type-2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. RESULTS Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). CONCLUSION Subjects with uncontrolled type-2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.

Antibacterial activities of root canal sealers against selected anaerobic bacteria

The antibacterial effects of four endodontic sealers were evaluated on six anaerobic bacteria and two facultative anaerobes commonly isolated from infected root canals. Calcium hydroxide powder mixed with saline solution was also tested. The agar diffusion test was used, and the zones of inhibition around each sealer were recorded and compared. Fill Canal, a zinc oxide-eugenol-based sealer, showed large zones of inhibition against all bacteria tested. Sealer 26, an epoxy resin containing calcium hydroxide, was inhibitory to most of the strains, but it was not effective against Porphyromonas endodontalis and Porphyromonas gingivalis . Next in order was calcium hydroxide followed by Sealapex, both with low activity. Apexit showed no antibacterial activity. Difficulties in interpreting the results of agar diffusion tests are recognized.

Periodontal debridement as a therapeutic approach for severe chronic periodontitis: a clinical, microbiological and immunological study

AIM To clinically, microbiologically and immunologically characterize periodontal debridement as a therapeutic approach for severe chronic periodontitis. MATERIAL AND METHODS Twenty-five patients presenting at least eight teeth with a probing pocket depth (PPD) of >or=5 mm and bleeding on probing (BOP) were selected and randomly assigned to quadrant-wise scaling and root planing or one session of full-mouth periodontal debridement. The following clinical outcomes were assessed: plaque index, BOP, position of gingival margin, relative attachment level (RAL) and PPD. Real-time PCR was used for quantitative analysis of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia. The enzyme-linked immunosorbent assay permitted the detection of IL-1beta, prostaglandin E(2), INF-gamma and IL-10 in gingival crevicular fluid (GCF). All the parameters were evaluated at baseline, and at 3 and 6 months after treatment. RESULTS Both the groups had similar means of PPD reduction and attachment gain over time. Besides a significant reduction in the bacterial level after treatment in both groups, microbiological analysis failed to demonstrate significant differences between them. Finally, no difference was observed between groups with respect to the levels of inflammatory mediators in GCF. CONCLUSION Periodontal debridement resulted in a similar clinical, microbiological and immunological outcome when compared with standard scaling and root planing and therefore may be a viable approach to deal with severe chronic periodontitis.

PPAR-γ agonist rosiglitazone prevents inflammatory periodontal bone loss by inhibiting osteoclastogenesis

Rosiglitazone (RGZ), an oral anti-hyperglycemic agent used for non-insulin-dependent diabetes mellitus, is a high-affinity synthetic agonist for peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Both in vitro and in vivo experiments have also revealed that RGZ possesses anti-inflammatory properties. Therefore, in the present study, we investigated the anti-inflammatory effects of RGZ in a rat model of periodontal disease induced by ligature placed around the mandible first molars of each animal. Male Wister rats were divided into four groups: 1) animals without ligature placement receiving administration of empty vehicle (control); 2) animals with ligature receiving administration of empty vehicle; 3) animals with ligature receiving administration with oral RGZ (10 mg/kg/day); and 4) animals with ligature receiving administration of subcutaneous RGZ (10 mg/kg/day). Thirty days after induction of periodontal disease, the animals were sacrificed, and mandibles and gingival tissues were removed for further analysis. An in vitro assay was also employed to test the inhibitory effects of RGZ on osteoclastogenesis. Histomorphological and immunohistochemical analyses of periodontal tissue demonstrated that RGZ-treated animals presented decreased bone resorption, along with reduced RANKL expression, compared to those animals with ligature, but treated with empty vehicle. Corresponding to such results obtained from in vivo experiments, RGZ also suppressed in vitro osteoclast differentiation in the presence of RANKL in MOCP-5 osteoclast precursor cells, along with the down-regulation of the expression of RANKL-induced TRAP mRNA. These data indicated that RGZ may suppress the bone resorption by inhibiting RANKL-mediated osteoclastogenesis elicited during the course of experimental periodontitis in rats.

Molecular detection of Bacteroides forsythus in infected root canals

The purpose of the present study was to investigate the occurrence of Bacteroides forsythus in infections of dental root canals. Eleven samples from infected root canals were analyzed by four different molecular methods. The prevalence of the monitored species varied as a function of the detection method. The polymerase chain reaction-DNA probe method after immunocapture yielded the highest prevalence value (6/11), whereas the lowest value was observed with the slot-blot (3/11). Of the 11 canal samples, 5 were positive by ELISA and 4 were positive by immunofluorescence. The presence of B. forsythus was detected by all four methods in 3/11 canals, whereas 4/11 appeared to be free of B. forsythus. Our data indicate that B. forsythus can be part of the endodontic microflora. The procedure consisting of immunomagnetic capture and a polymerase chain reaction-DNA probe assay can be useful as an alternative to culture for clinical studies of the species infecting human dental pulp.