Molecular detection of in-vivo microbial contamination of metallic orthodontic brackets by checkerboard DNA-DNA hybridization

Introduction: Knowing the microbiota that colonizes orthodontic appliances is important for planning strategies and implementing specific preventive measures during treatment. The purpose of this clinical trial was to evaluate in vivo the contamination of metallic orthodontic brackets with 40 DNA probes for different bacterial species by using the checkerboard DNA-DNA hybridization (CDDH) technique. Methods: Eighteen patients, 11 to 29 years of age having fixed orthodontic treatment, were enrolled in the study. Each subject had 2 new metallic brackets bonded to different premolars in a randomized manner. After 30 days, the brackets were removed and processed for analysis by CDDH. Data on bacterial contamination were analyzed descriptively and with the Kruskal-Wallis and Dunn post tests (alpha = 0.05). Forty microbial species (cariogenic microorganisms, bacteria of the purple, yellow, green, orange complexes, "red complex + Treponema socranskii," and the cluster of Actinomyces) were assessed. Results: Most bacterial species were present in all subjects, except for Streptococcus constellatus, Campylobacter rectus, Tannerella forsythia, T socranskii, and Lactobacillus acidophillus (94.4%), Propionibacterium acnes I and Eubacterium nodatum (88.9%), and Treponema denticola (77.8%). Among the cariogenic microorganisms, Streptococcus mutans and Streptococcus sobrinus were found in larger numbers than L acidophillus and Lactobacillus casei (P < 0.001). The periodontal pathogens of the orange complex were detected in larger numbers than those of the "red complex + T socranskii" (P < 0.0001). Among the bacteria not associated with specific pathologies, Veillonella parvula (purple complex) was the most frequently detected strain (P < 0.0001). The numbers of yellow and green complex bacteria and the cluster of Actinomyces were similar (P > 0.05). Conclusions: Metallic brackets in use for 1 month were multi-colonized by several bacterial species, including cariogenic microorganisms and periodontal pathogens, reinforcing the need for meticulous oral hygiene and additional preventive measures to maintain oral health in orthodontic patients. (Am J Orthod Dentofacial Orthop 2012;141:24-9)

Clinical and Microbiologic Evaluation, by Real-Time Polymerase Chain Reaction, of Non-Surgical Treatment of Aggressive Periodontitis Associated With Amoxicillin and Metronidazole

Background: The aim of the present study is to evaluate the clinical and microbiologic changes resulting from non-surgical periodontal treatment associated with amoxicillin and metronidazole in individuals with aggressive periodontitis. Methods: Fifteen individuals with aggressive periodontitis received non-surgical periodontal treatment and 45 days after completion of treatment were treated with antibiotics. Clinical data and samples of subgingival plaque were collected at baseline, 45 days after the non-surgical periodontal treatment, and 1 month after the use of antimicrobial agents. After 3 and 6 months, only clinical data were collected. The presence and quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), and Dialister pneumosintes were determined by real-time polymerase chain reaction. Results: All clinical parameters, with the exception of clinical attachment level (CAL), had significantly (P<0.05) improved at the end of the third month after non-surgical therapy associated with antibiotics. There was significant (P<0.05) reduction in the quantities of Td and Tf. After 1 month, there were significant (P<0.05) reductions in the frequencies of Pg and Tf. Conclusion: Non-surgical mechanical treatment associated with the use of amoxicillin and metronidazole led to an improvement in all clinical parameters studied, except for CAL, and significantly reduced the amount of subgingival Tf and Td. J Periodontal 2012;83:744-752.

Association between IL8 haplotypes and pathogen levels in chronic periodontitis

Chronic periodontitis (CP) is considered to be a multifactorial disease influenced by microbial and genetic factors. The aim of the present study was to investigate whether the genetic susceptibility to CP in individuals with the IL8 ATC/TTC haplotype is associated with subgingival levels of periodontopathogens. Sixty-five individuals, grouped according to the presence (n=28) or absence (n=37) of the IL8 haplotype, were evaluated. After clinical periodontal evaluation, each group was subdivided according to the presence (CP) or absence (H) of periodontitis. Four subgingival samples were obtained from CP and two samples per subject from H patients. The levels and proportions of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were analyzed using quantitative real-time polymerase chain reaction (q-PCR). No differences were found in the proportion of periodontopathogenic bacteria between groups with the presence or absence of the IL8 haplotype. However, in the CP groups, the levels of periodontopathogens were significantly higher in the individuals withou the IL8 haplotype than in the individuals with the IL8 haplotype. These results suggest that periodontal destruction may occur in patients who are considered to be genetically susceptible to CP with a lower microbial challenge because of the presence of the IL8 ATC/TTC haplotype than in patients without this haplotype.

Periodontopathogens levels and clinical response to periodontal therapy in individuals with the interleukin-4 haplotype associated with susceptibility to chronic periodontitis

Periodontitis is an inflammatory disease that results from an interaction between dental biofilm agents and the host immune-inflammatory response. Periodontopathogenic organisms, such as Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, as well as the host's susceptibility, represented by the host's genetic makeup, are the key factors that influence this complex disease. Recently, we identified haplotypes in the IL4 gene that were associated with chronic periodontitis (CP). This study aimed to evaluate whether subjects with different IL4 haplotypes (TCI/CCI and TTD/CTI) would be differentially colonized by periodontopathogens and whether they would respond differently to non-surgical periodontal therapy. Thirty-nine patients carrying the IL4 haplotype of genetic susceptibility to CP (IL4+) or protection against CP (IL4-) were evaluated. Those groups were further subdivided into individuals with CP (CP IL4+ or CP IL4-) and those that were periodontally healthy (H) (H IL4+ or H IL4-). CP patients were submitted to non-surgical periodontal therapy. Clinical and microbiological analyses were performed considering the data at baseline and 45 and 90 days after periodontal therapy. Periodontopathogens levels were evaluated by absolute quantitative polymerase chain reaction (qPCR). The baseline data revealed that the total levels of periodontopathogens were higher in the CP IL4+ than in the CP IL4- groups. Clinical analyses revealed that the periodontal therapy was equally effective, independent of the subject's IL4 genetic load. The TCI/CCI IL4 haplotype, previously associated with genetic susceptibility to CP, was also associated with increased levels of periodontopathogenic bacteria, but this genetic background did not influence the response to non-surgical periodontal treatment.

Pathogen levels and clinical response to periodontal treatment in patients with Interleukin 8 haplotypes

The aim of this study was to investigate the effect of non-surgical treatment of periodontitis on the levels of periodontopathogens and clinical parameters in patients with different genetic backgrounds produced by polymorphisms in the Interleukin (IL8) gene. Thirty patients grouped according to IL8 ATC/TTC or AGT/TTC haplotypes were submitted to non-surgical periodontal treatment. Levels of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were determined in 240 subgingival plaque samples by qPCR. The association between IL8 haplotypes and the levels of periodontopathogens and clinical parameters was investigated by multilevel analysis accounting for the clustering of diseased sites analyzed within patients. It was observed that neither levels of periodontopathogens nor non-surgical treatment was associated with the IL8 haplotype. The clinical parameters after periodontal treatment were similar in diseased and healthy sites, independently of the IL8 haplotype. Nonetheless, in the same period, diseased sites of AGT/TTC patients harbored higher levels of P. gingivalis, T. denticola, T. forsythia, and red complex than those of ATC/TTC patients. However, the non-surgical periodontal therapy decreased the levels of these periodontopathogens and of the tested clinical parameters of diseased sites in both groups. Non-surgical therapy is equally effective in improving clinical parameters and decreasing the levels of periodontopathogens, independent of the genotype groups produced by the IL8 haplotype.

Altered phenotype and function of dendritic cells in individuals with chronic periodontitis

OBJECTIVE: To investigate the effects of periodontal bacterial lysates on maturation and function of mature monocyte-derived dendritic cells (m-MDDCs) derived from individuals with chronic periodontitis (CP) or healthy periodontal tissue (HP). DESIGN: m-MDDCs derived from peripheral blood monocytes, cultured for 7 days in presence of interleukin (IL)-4 and granulocyte-macrophage colony stimulating factor (GM-CSF), were stimulated with lysates of Streptococcus sanguinis, Prevotella intermedia, Porphyromonas gingivalis, or Treponema denticola on day 4, and were then phenotyped. IL-10, IL-12 and IFN-gamma concentration in the supernatant of cultures were measured. RESULTS: Expression of HLA-DR was lower in bacterial-unstimulated mature m-MDDC from CP compared to HP (p=0.04), while expression of CD1a and CD123 were higher in CP. The expression pattern of HLA-DR, CD11c, CD123, and CD1a did not change on bacterial stimulation, regardless of the bacteria. Stimulation with P. intermedia upregulated CD80 and CD86 in CP cells (p≤0.05). Production of IL-12p70 by bacterial-unstimulated m-MDDCs was 5.8-fold greater in CP compared to HP. Bacterial stimulation further increased IL-12p70 production while decreasing IL-10. Significantly more IFN-gamma was produced in co-cultures of CP m-MDDCs than with HP m-MDDCs when cells were stimulated with P. intermedia (p=0.009). CONCLUSIONS: Bacterial-unstimulated m-MDDC from CP exhibited a more immature phenotype but a cytokine profile biased towards proinflammatory response; this pattern was maintained/exacerbated after bacterial stimulation. P. intermedia upregulated co-stimulatory molecules and IFN-gamma expression in CP m-MDDC. These events might contribute to periodontitis pathogenesis