A three-year prospective study of adult subjects with gingivitis II: microbiological parameters

Brazilian Red Propolis Is as Effective as Amoxicillin in Controlling Red-Complex of Multispecies Subgingival Mature Biofilm In Vitro

This study investigated the effects of Brazilian Red Propolis (BRP) extract on seven-day-old multispecies subgingival biofilms. Mixed biofilm cultures containing 31 species associated with periodontal health or disease were grown for six days on a Calgary device. Then, mature biofilms were treated for 24 h with BRP extract at different concentrations (200-1600 µg/mL), amoxicillin (AMOXI) at 54 µg/mL (positive control) or vehicle (negative control). Biofilm metabolic activity was determined by colorimetry, and bacterial counts/proportions were determined by DNA-DNA hybridization. Data were analyzed by Kruskal-Wallis and Dunn's tests. Treatment with BRP at 1600, 800 and 400 μg/mL reduced biofilm metabolic activity by 56%, 56% and 57%, respectively, as compared to 65% reduction obtained with AMOXI. Mean total cell counts were significantly reduced in all test groups (~50-55%). Lower proportions of red, green and yellow complex species were observed upon treatment with BRP (400 µg/mL) and AMOXI, but only AMOXI reduced the proportions of Actinomyces species. In conclusion, BRP extract was as effective as AMOXI in killing seven-day-old multispecies biofilm pathogens and did not affect the levels of the host-compatible Actinomyces species. These data suggest that BRP may be an alternative to AMOXI as an adjunct in periodontal therapy. In vivo studies are needed to validate these results.

Sex-specific differences in the salivary microbiome of caries-active children

Background and Objectives: Dental caries is a chronic disease affecting young children and has multi-factorial risk factors. The purpose of this work was to identify sex-specific differences in the salivary microbiota within caries-active children. Design: Saliva specimens were collected from 85 children (boys: 41; girls: 44) between the ages of 2-12 years. Salivary microbial DNA was subjected to PCR amplification using V3-V4 16S rDNA-specific primers and next-generation sequencing. Results: Significant sex differences in salivary microbiota were found between caries-active boys versus caries-active girls. Neisseria flavescens, Rothia aeria, and Haemophilus pittmaniae were found at significantly higher levels in caries-active boys. In contrast, Lactococcus lactis, Selenomonas species HOT 126, Actinobaculum species HOT 183, Veillonella parvula, and Alloprevotella species HOT 473 were found at significantly higher levels in caries-active girls. Conclusion: We have found the acid-generating, cariogenic Lactococcus lactis to be much more abundant in caries-active girls than caries-active boys, indicating that this microorganism may play a more significant role in shaping the cariogenic microbiome in girls. In addition, in caries-active girls, Alloprevotella species HOT 473 was the only species that exhibited both significant sex differences (4.4-fold difference; p=0.0003) as well as high abundance in numbers (1.85% of the total microbial population).

Exploring the microbiome of healthy and diseased peri-implant sites using Illumina sequencing

AIM

To compare the microbiome of healthy (H) and diseased (P) peri-implant sites and determine the core peri-implant microbiome.

MATERIALS AND METHODS

Submucosal biofilms from 32 H and 35 P sites were analysed using 16S rRNA sequencing (MiSeq, Illumina), QIIME and HOMINGS. Differences between groups were determined using principal coordinate analysis (PCoA), t tests and Wilcoxon rank sum test and FDR-adjusted. The peri-implant core microbiome was determined.

RESULTS

PCoA showed partitioning between H and P at all taxonomic levels. Bacteroidetes, Spirochetes and Synergistetes were higher in P, while Actinobacteria prevailed in H (p < .05). Porphyromonas and Treponema were more abundant in P while Rothia and Neisseria were higher in H (p < .05). The core peri-implant microbiome contained Fusobacterium, Parvimonas and Campylobacter sp. T. denticola, and P. gingivalis levels were higher in P, as well as F. alocis, F. fastidiosum and T. maltophilum (p < .05).

CONCLUSION

The peri-implantitis microbiome is commensal-depleted and pathogen-enriched, harbouring traditional and new pathogens. The core peri-implant microbiome harbours taxa from genera often associated with periodontal inflammation.

Gingival Inflammation Associates with Stroke--A Role for Oral Health Personnel in Prevention: A Database Study

OBJECTIVES

Gingival inflammation is the physiological response to poor oral hygiene. If gingivitis is not resolved the response will become an established lesion.We studied whether gingivitis associates with elevated risk for stroke. The hypothesis was based on the periodontitis-atherosclerosis paradigm.

METHODS

In our prospective cohort study from Sweden 1676 randomly selected subjects were followed up from 1985 to 2012. All subjects underwent clinical oral examination and answered a questionnaire assessing background variables such as socio-economic status and pack-years of smoking. Cases with stroke were recorded from the Center of Epidemiology, Swedish National Board of Health and Welfare, Sweden, and classified according to the WHO International Classification of Diseases. Unpaired t-test, chi-square tests, and multiple logistic regression analyses were used.

RESULTS

Of the 1676 participants, 39 subjects (2.3%) had been diagnosed with stroke. There were significant differences between the patients with stroke and subjects without in pack-years of smoking (p = 0.01), prevalence of gingival inflammation (GI) (p = 0.03), and dental calculus (p = 0.017). In a multiple regression analysis the association between GI, confounders and stroke, GI showed odds ratio 2.20 (95% confidence interval 1.02-4.74) for stroke.

CONCLUSION

Our present findings showed that gingival inflammation clearly associated with stroke in this 26-year cohort study. The results emphasize the role of oral health personnel in prevention.

Reconstitution and structure of a bacterial Pnkp1-Rnl-Hen1 RNA repair complex

Ribotoxins cleave essential RNAs for cell killing, and RNA repair neutralizes the damage inflicted by ribotoxins for cell survival. Here we report a new bacterial RNA repair complex that performs RNA repair linked to immunity. This new RNA repair complex is a 270-kDa heterohexamer composed of three proteins-Pnkp1, Rnl and Hen1-that are required to repair ribotoxin-cleaved RNA in vitro. The crystal structure of the complex reveals the molecular architecture of the heterohexamer as two rhomboid-shaped ring structures of Pnkp1-Rnl-Hen1 heterotrimer fused at the Pnkp1 dimer interface. The four active sites required for RNA repair are located on the inner rim of each ring. The architecture and the locations of the active sites of the Pnkp1-Rnl-Hen1 heterohexamer suggest an ordered series of repair reactions at the broken RNA ends that confer immunity to recurrent damage.

Microbiologic Observations After Four Treatment Strategies Among Patients With Periodontitis Maintaining a High Standard of Oral Hygiene: Secondary Analysis of a Randomized Controlled Clinical Trial

BACKGROUND

The benefit of full-mouth disinfection (FDIS) over traditional scaling and root planing (SRP), with or without adjunctive metronidazole, when treating chronic destructive periodontitis remains equivocal, as does the long-term association between clinical and microbiologic outcomes after such strategies. The aim of this study is to examine the relationship between clinical and microbiologic outcomes of four different treatment strategies for chronic destructive periodontitis among patients who maintain excellent oral hygiene and low gingival bleeding scores.

METHODS

One hundred eighty-four patients with periodontitis and capable of maintaining a high standard of oral hygiene were randomly allocated to one of four treatment groups: 1) FDIS + metronidazole; 2) FDIS + placebo; 3) SRP + metronidazole; and 4) SRP + placebo. Recordings of plaque, bleeding on probing, probing depth (PD), and clinical attachment level were carried out in four sites per tooth at baseline, 3 and 12 months after treatment. Before treatment, pooled subgingival samples were obtained from the five deepest pockets, which were sampled again 3 and 12 months after treatment. Microbiologic assessments of eight putative periodontal pathogens were performed using the checkerboard DNA-DNA hybridization method.

RESULTS

Levels of bacterial species were already relatively low at baseline. The only microbial factor statistically significantly associated with the clinical outcomes of treatment after 12 months was the association between reductions of Tannerella forsythia and being free from PD ≥5 mm.

CONCLUSION

In this clinical trial, the only microbial factor associated with the clinical outcomes after 12 months was a statistically significant association between the reductions of T. forsythia and being free from PD ≥5 mm.

Oral epithelial cell responses to multispecies microbial biofilms

This report describes the use of a novel model of multispecies biofilms to stimulate profiles of cytokines/chemokines from oral epithelial cells that contribute to local inflammation in the periodontium. Streptococcus gordonii (Sg)/S. oralis (So)/S. sanguinis (Ss) and Sg/Fusobacterium nucleatum (Fn)/Porphyromonas gingivalis (Pg) biofilms elicited significantly elevated levels of IL-1α and showed synergistic stimulatory activity compared with an additive effect of the 3 individual bacteria. Only the Sg/Actinomyces naeslundii (An)/Fn multispecies biofilms elicited IL-6 levels above those of control. IL-8 was a primary response to the Sg/An/Fn biofilms, albeit the level was not enhanced compared with a predicted composite level from the monospecies challenges. These results represent some of the first data documenting alterations in profiles of oral epithelial cell responses to multispecies biofilms.

Preliminary characterization of the oral microbiota of Chinese adults with and without gingivitis

BACKGROUND

Microbial communities inhabiting human mouth are associated with oral health and disease. Previous studies have indicated the general prevalence of adult gingivitis in China to be high. The aim of this study was to characterize in depth the oral microbiota of Chinese adults with or without gingivitis, by defining the microbial phylogenetic diversity and community-structure using highly paralleled pyrosequencing.

METHODS

Six non-smoking Chinese, three with and three without gingivitis (age range 21-39 years, 4 females and 2 males) were enrolled in the present cross-sectional study. Gingival parameters of inflammation and bleeding on probing were characterized by a clinician using the Mazza Gingival Index (MGI). Plaque (sampled separately from four different oral sites) and salivary samples were obtained from each subject. Sequences and relative abundance of the bacterial 16 S rDNA PCR-amplicons were determined via pyrosequencing that produced 400 bp-long reads. The sequence data were analyzed via a computational pipeline customized for human oral microbiome analyses. Furthermore, the relative abundances of selected microbial groups were validated using quantitative PCR.

RESULTS

The oral microbiomes from gingivitis and healthy subjects could be distinguished based on the distinct community structures of plaque microbiomes, but not the salivary microbiomes. Contributions of community members to community structure divergence were statistically accessed at the phylum, genus and species-like levels. Eight predominant taxa were found associated with gingivitis: TM7, Leptotrichia, Selenomonas, Streptococcus, Veillonella, Prevotella, Lautropia, and Haemophilus. Furthermore, 98 species-level OTUs were identified to be gingivitis-associated, which provided microbial features of gingivitis at a species resolution. Finally, for the two selected genera Streptococcus and Fusobacterium, Real-Time PCR based quantification of relative bacterial abundance validated the pyrosequencing-based results.

CONCLUSIONS

This methods study suggests that oral samples from this patient population of gingivitis can be characterized via plaque microbiome by pyrosequencing the 16 S rDNA genes. Further studies that characterize serial samples from subjects (longitudinal study design) with a larger population size may provide insight into the temporal and ecological features of oral microbial communities in clinically-defined states of gingivitis.

Smoking and periodontal disease: discrimination of antibody responses to pathogenic and commensal oral bacteria

Smoking is an independent risk factor for the initiation, extent and severity of periodontal disease. This study examined the ability of the host immune system to discriminate commensal oral bacteria from pathogens at mucosal surfaces, i.e. oral cavity. Serum immunoglobulin (Ig)G antibody reactive with three pathogenic and five commensal oral bacteria in 301 current smokers (age range 21-66 years) were examined by enzyme-linked immunosorbent assay. Clinical features of periodontal health were used as measures of periodontitis. Antibody to the pathogens and salivary cotinine levels were related positively to disease severity; however, the antibody levels were best described by the clinical disease unrelated to the amount of smoking. The data showed a greater immune response to pathogens than commensals that was related specifically to disease extent, and most noted in black males. Significant correlations in individual patient responses to the pathogens and commensals were lost with an increasing extent of periodontitis and serum antibody to the pathogens. Antibody to Porphyromonas gingivalis was particularly distinct with respect to the discriminatory nature of the immune responses in recognizing the pathogens. Antibody responses to selected pathogenic and commensal oral microorganisms differed among racial groups and genders. The antibody response to the pathogens was related to disease severity. The level of antibody to the pathogens, and in particular P. gingivalis, was correlated with disease severity in black and male subsets of patients. The amount of smoking did not appear to impact directly serum antibody levels to these oral bacteria.

[Mouthwash solutions containing microencapsulated natural extracts: Clinical results on dental plaque and gingivitis]

INTRODUCTION

New mouthwash solutions containing microencapsulated natural extracts have been developed. Besides antiseptic activity, these solutions have antioxidant and immunoregulatory properties on oral tissues. The objective of this preliminary clinical study was to assess the efficiency of a mouthwash containing microencapsulated natural extracts (GingiNat, LoB5 Foundation, Paris, France) on gingivitis.

PATIENTS AND METHODS

Twenty volunteers (37 + or - 2 years) with significant gingivitis (bleeding when tooth-brushing) used a 6% GingiNat mouthwash solution, two to three times per day (according to oral hygiene habits) for 21 days in addition to their usual oral care. Each volunteer was examined at day 0, 4, 7 and 21. The Löe and Silness Plaque Index, the Russel Periodontal Index, a breath index (halitosis), and oral tissue tolerance were assessed. Finally, each volunteer filled in a daily follow-up form and answered a questionnaire on tolerance and acceptability.

RESULTS

A significant decrease of the dental plaque index was observed on day 4, 7, and 21, in respectively 29, 48 and 71% of volunteers. This decrease reached 18% on day 4 (p=0.014), 32% on day 7 (p=0.002), and 47% on day 21 (p<0.001). A significant decrease of the periodental index was observed on day 4, 7 and 21, in respectively 52, 81 and 95% of volunteers. This decrease reached 30% (p=0.001) on day 4, 49% (p<0.001) on day 7, and 78% (p<0.001) on day 21. A significant improvement of the breath index was noted on day 4, 7, and 21, in respectively 43, 52 and 48% of volunteers. This improvement reached 29% (p=0.004) on day 4, 35% (p=0.001) on day 7, and 32% (p=0.002) on day 21. The mouthwash was well tolerated. The patients liked its effectiveness and organoleptic properties. All patients expressed the wish to continue using this solution.

DISCUSSION

The GingiNat mouthwash solution at 6% had a significant efficiency on plaque, gingivitis, and halitosis after 21 days of use. This makes it a good complementary treatment for gingivitis. Tolerance and acceptability were good despite the long and repeated use. Further studies are needed to have a detailed analysis of its efficiency in the long run and on patients presenting with various forms of periodontitis.

Bacteria-derived hydrogen sulfide promotes IL-8 production from epithelial cells

Hydrogen sulfide (H(2)S), a volatile sulfur compound, is implicated as a cause of inflammation, especially when it is produced by bacteria colonizing gastrointestinal organs. However, it is unclear if H(2)S produced by periodontal pathogens affects the inflammatory responses mediated by oral/gingival epithelial cells. Therefore, the aims of this study were (1) to compare the in vitro production of H(2)S among 14 strains of oral bacteria and (2) to evaluate the effects of H(2)S on inflammatory response induced in host oral/gingival epithelial cells. Porphyromonas gingivalis (Pg) produced the most H(2)S in culture, which, in turn, resulted in the promotion of proinflammatory cytokine IL-8 from both gingival and oral epithelial cells. The up-regulation of IL-8 expression was reproduced by the exogenously applied H(2)S. Furthermore, the mutant strains of Pg that do not produce major soluble virulent factors, i.e. gingipains, still showed the production of H(2)S, as well as the promotion of epithelial IL-8 production, which was abrogated by H(2)S scavenging reagents. These results demonstrated that Pg produces a concentration of H(2)S capable of up-regulating IL-8 expression induced in gingival and oral epithelial cells, revealing a possible mechanism that may promote the inflammation in periodontal disease.

The oral microbiota: living with a permanent guest

The oral cavity of healthy individuals contains hundreds of different bacterial, viral, and fungal species. Many of these can associate to form biofilms, which are resistant to mechanical stress or antibiotic treatment. Most are also commensal species, but they can become pathogenic in responses to changes in the environment or other triggers in the oral cavity, including the quality of an individual's personal hygiene. The complexity of the oral microbiome is being characterized through the newly developed tools of metagenomics. How the microbiome of the oral cavity contributes to health and disease is attracting the interest of a growing number of cell biologists, microbiologists, and immunologists.

Clinical and Microbiologic Changes Associated With the Combined Use of a Powered Toothbrush and a Triclosan/Copolymer Dentifrice: A 3-Year Prospective Study

BACKGROUND

Different means are available for self-performed oral hygiene. The aim of this study was to evaluate the clinical and microbiologic effects of a preventive homecare program including the combined use of a powered toothbrush and a triclosan/copolymer-containing dentifrice.

METHODS

A total of 160 adult subjects without signs of destructive periodontal disease were recruited for this 3-year randomized controlled trial. The subjects were assigned to a homecare program using an oscillating/rotating powered toothbrush and a triclosan/copolymer/fluoride-containing dentifrice (test) or a manual toothbrush and a standard fluoride-containing dentifrice (control). Supragingival polishing and reinforcement of homecare procedures were provided every 6 months. Plaque, bleeding on probing (BOP), and probing depth (PD) were scored at baseline and after 1, 2, and 3 years. Subgingival plaque samples were taken from the mesial aspect of each tooth at baseline and after 1, 2, and 3 years and were analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. All data analyses were based on "intention-to-treat" with the subject as the statistical unit.

RESULTS

Compared to baseline, no significant changes in clinical parameters were observed during the 3 years, except for a reduction in the mean PD at the 2- and 3-year follow-up examinations (P <0.05). No significant differences were found between the two groups with regard to plaque, BOP, or PD or in the mean counts of the 40 species at any time point.

CONCLUSION

The study failed to prove additional benefits of the combined use of a powered toothbrush and a triclosan/copolymer-containing dentifrice in adult subjects without signs of destructive periodontal disease.