Subgingival microbiome in periodontal health, gingivitis and different stages of periodontitis

AIM

To characterize the subgingival microbiome in subjects with different periodontal health statuses.

MATERIALS AND METHODS

In this cross-sectional observational study, subgingival samples were harvested from Spanish subjects with different periodontal health statuses, based on the 2018 Classification of Periodontal and Peri-Implant Diseases and Conditions. Samples were processed using high-throughput sequencing technologies (Illumina MiSeq). Taxa differentially abundant were identified using Analysis of Compositions of Microbiomes with Bias Correction (ANCOM-BC). α- and β-diversity metrics were calculated using q2-diversity in QIIME2. The analyses were adjusted for age, gender and smoking status.

RESULTS

The identified subgingival microbiome showed statistically significant differences among subjects, categorized into periodontal health, gingivitis and stages I-II and III-IV periodontitis (p < .05). In patients with severe (stages III-IV) periodontitis, the genera Filifactor and Fretibacterium were detected 24 times more frequently than in periodontally healthy subjects. Similarly, the genera Porphyromonas, Prevotella and Tannerella were detected four times more frequently (p < .05). The genera Granulicatella, Streptococcus, Paracoccus, Pseudomonas, Haemophilus, Actinobacteria, Bergeyella and Capnocytophaga were significantly associated with healthier periodontal status (p < .05).

CONCLUSIONS

Significant differences were detected in the subgingival microbiome among periodontal health, gingivitis and stages I-II or III-IV periodontitis, suggesting overlapping, yet distinguishable microbial profiles.

Efficacy of adjunctive measures in peri-implant mucositis. A systematic review and meta-analysis

AIM

To answer the following PICO question: In systemically healthy humans with peri-implant mucositis, what is the efficacy of patient-performed or administered (by prescription) measures used adjunctively to submarginal instrumentation, as compared to submarginal instrumentation alone or combined with a negative control, in terms of reducing bleeding on probing (BOP), in randomized controlled clinical trials (RCTs) with at least 3 months of follow-up?

MATERIALS AND METHODS

Three databases were searched until April 2022. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) and predictive intervals were calculated.

RESULTS

Sixteen parallel RCTs corresponding to 14 studies with low/moderate risk of bias were included. Test groups showed greater reductions in BOP (%) than control groups (n_studies  = 16; n_patients  = 650; WMD = 14.25%; 95% CI [9.06-19.45]; p < .001; I²  = 98.7%). The greatest WMD in BOP reductions (%) were obtained by antiseptics (n_s  = 5; n_p  = 229; WMD = 22.72%; 95% CI [19.40-26.04]; p < 0.001; I²  = 94.8%), followed by probiotics (n_s  = 6; n_p  = 260; WMD = 12.11%; 95% CI [3.20-21.03]; p = .008; I²  = 93.3%) and systemic antibiotics (n_s  = 3; n_p  = 101; WMD = 5.97%; 95% CI [1.34-10.59]; p = .012; I²  = 58.1%). Disease resolution was scarcely reported (n = 6).

CONCLUSIONS

Significant clinical improvements can be obtained when professional submarginal instrumentation is combined with patient-performed or administered (by prescription) adjunctive measures, although a complete disease resolution may not be achieved.

Neuroinflammation related to the blood-brain barrier and sphingosine-1-phosphate in a pre-clinical model of periodontal diseases and depression in rats

AIM

To explore the potential mechanisms of neuroinflammation (microglia, blood-brain barrier [BBB] permeability, and the sphingosine-1-phosphate [S1P] pathways) resulting from the association between periodontitis and depression in rats.

MATERIALS AND METHODS

This pre-clinical in vivo experimental study used Wistar rats, in which experimental periodontitis (P) was induced by using oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum. Then, a chronic mild stress (CMS) model was implemented to induce a depressive-like behaviour, resulting in four groups: P with CMS (P+CMS+), P without CMS (P+CMS-), CMS without P (P-CMS+), and control (P-CMS-). After harvesting brain samples, protein/mRNA expression analyses and fluorescence immunohistochemistry were performed in the frontal cortex (FC). Results were analysed by ANOVA.

RESULTS

CMS exposure increased the number of microglia (an indicator of neuroinflammation) in the FC. In the combined model (P+CMS+), there was a decrease in the expression of tight junction proteins (zonula occludens-1 [ZO-1], occludin) and an increase in intercellular and vascular cell adhesion molecules (ICAM-1, VCAM-1) and matrix metalloproteinase 9 (MMP9), suggesting a more severe disruption of the BBB. The enzymes and receptors of S1P were also differentially regulated.

CONCLUSIONS

Microglia, BBB permeability, and S1P pathways could be relevant mechanisms explaining the association between periodontitis and depression.

Effect of orthodontic therapy in periodontitis and non-periodontitis patients: a systematic review with meta-analysis

AIM

To answer these PICO questions: #1: In adult patients with malocclusion, what are the effects of orthodontic tooth movement (OTM) on clinical attachment level (CAL) changes in treated periodontitis patients with a healthy but reduced periodontium compared to non-periodontitis patients? #2: In adult patients with treated periodontitis and malocclusion, which is the efficacy of skeletal anchorage devices compared to conventional systems in terms of orthodontic treatment outcomes?

MATERIAL AND METHODS

Seven databases were searched until June 2020 looking for randomized, non-randomized trials and case series. Mean effects (ME) and 95% confidence intervals (CIs) were calculated.

RESULTS

Twenty-six studies with high risk of bias were included. PICO#1: In 26 patients without periodontitis and in 69 treated periodontitis patients, minimal changes in periodontal outcomes were reported after orthodontic therapy (p>0.05). A significant CAL gain (mm) (ME=3.523; 95% CI [2.353; 4.693]; p<0.001) was observed in 214 patients when periodontal outcomes were retrieved before a combined periodontal and orthodontic therapy. PICO#2: Orthodontic variables were scarcely reported and objective assessment of the results on orthodontic therapy were missing.

CONCLUSIONS

Based on a small number of low-quality studies, in non-periodontitis and in stable treated periodontitis patients, OTM had no significant impact on periodontal outcomes.

Periodontal diseases and depression: A pre-clinical in vivo study

AIM

To analyse, through a pre-clinical in vivo model, the possible mechanisms linking depression and periodontitis at behavioural, microbiological and molecular levels.

MATERIALS AND METHODS

Periodontitis (P) was induced in Wistar:Han rats (oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum) during 12 weeks, followed by a 3-week period of Chronic Mild Stress (CMS) induction. Four groups (n = 12 rats/group) were obtained: periodontitis and CMS (P+CMS+); periodontitis without CMS; CMS without periodontitis; and control. Periodontal clinical variables, alveolar bone levels (ABL), depressive-like behaviour, microbial counts and expression of inflammatory mediators in plasma and brain frontal cortex (FC), were measured. ANOVA tests were applied.

RESULTS

The highest values for ABL occurred in the P+CMS+ group, which also presented the highest expression of pro-inflammatory mediators (TNF-α, IL-1β and NF-kB) in frontal cortex, related to the lipoprotein APOA1-mediated transport of bacterial lipopolysaccharide to the brain and the detection of F. nucleatum in the brain parenchyma. A dysregulation of the hypothalamic-pituitary-adrenal stress axis, reflected by the increase in plasma corticosterone and glucocorticoid receptor levels in FC, was also found in this group.

CONCLUSIONS

Neuroinflammation induced by F. nucleatum (through a leaky mouth) might act as the linking mechanism between periodontal diseases and depression.

Subgingival microbiological profile of periodontitis patients in Dominican Republic

Several studies have tried to associate the presence of different pathogens with the onset and progression ofperiodontitis, reporting a wide variety of results from different populations and environments. The aim of this study was to determine the main periodontal pathogens present in the subgingival biofilm of Dominican patients with periodontitis, by using specific microbiological culturing techniques. Periodontitis patients were selected after a full-mouth periodontal evaluation, and assigned to different periodontitis groups based on percentage of affected locations. Subgingival samples were collected and analyzed by means of specific culture techniques. Anaerobic counts, frequency of detection and proportions of target pathogens were calculated. Variables were analyzed by means of Student's T-test or chi-square test. Twenty-nine subjects were recruited, of whom 17 were diagnosed with generalized periodontitis (GenP) and 12 with localized periodontitis (LocP). The most prevalent bacterial species in both groups was Prevotella intermedia (94.1% in GenP and 91.7% in LocP), followed by Porphyromonas gingivalis (88.2% in GenP and 83.3% in LocP). Total microbiota in subgingival samples was 1.3 x107 colony-forming units (CFU)/mL (standard deviation, SD=1.5 x107) and 9.6x10s CFU/mL (SD=1.1 x107) in GenP and LocP subjects, respectively, though differences were not statistically significant (p=0.222). The highest counts were observed for P gingivalis in both groups, with mean concentration 2.5x10s CFU/mL (6.1x10s) in GenP and 2.9x10s CFU/mL (5x10s) in LocP, with no statistically significant difference (p=0.879). These results suggest that relevant periodontal pathogens are found with diversity and abundance in the subgingival microbiota of adult Dominican patients with periodontitis.

Detection and quantification of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in bacteremia induced by interdental brushing in periodontally healthy and periodontitis patients

OBJECTIVE

This study was aimed to compare the presence and amounts of bacteremia induced by interdental brushing in periodontally healthy (H) and periodontitis (P) individuals using culture based (direct culture [DC]) and molecular based techniques (real-time quantitative polymerase chain reaction [qPCR]) in a cross-sectional study model.

MATERIALS AND METHODS

After a full mouth periodontal evaluation, blood samples were taken before and 1 min after professionally-administered interdental brushing. These samples were analyzed by DC and qPCR, targeting Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Subgingival samples were also collected and analyzed. Student t-test, chi-squar tests and correlations were used for analyzing the data.

RESULTS

Thirty individuals per group were included. P. gingivalis and A. actinomycetemcomitans were detected with qPCR methods, but not with DC. At baseline, bacteremia was observed in 5 P patients (16.7%) and in 2 H individuals (6.6%) (p = 0.421). After interdental brushing, bacteremia was only observed in 2 P patients (6.6%) (p = 0.901). A positive correlation between subgingival and blood levels of A. actinomycetemcomitans was observed (r = 0.3; p = 0.013).

CONCLUSION

Bacteremia related to A. actinomycetemcomitans and P. gingivalis did not significantly increase after a single session of use of interdental brushes.

Validation of a multiplex qPCR assay for the identification and quantification of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis: In vitro and subgingival plaque samples

OBJECTIVE

To validate a multiplex qPCR (m-qPCR) assay for the simultaneous identification and quantification of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis in subgingival samples.

MATERIAL AND METHODS

In vitro samples: DNA combinations of A. actinomycetemcomitans and P. gingivalis in similar or different concentrations were prepared. qPCR and m-qPCR were performed using the same primers and hydrolysis probes specific for 16SrRNA genes. Results were analyzed using intra-class (ICCs) and Lin's correlation coefficients (r) based on quantification cycle (Cq) values. Subgingival plaque samples: a cross-sectional study analyzing subgingival plaque samples harvested from periodontally-healthy and chronic periodontitis patients. Samples were processed by either qPCR or m-qPCR targeting both bacteria. Sensitivity, specificity, predictive values and Lińs correlation coefficients (r) were calculated using CFU/mL as primary outcome.

RESULTS

In vitro samples: m-qPCR yielded a good reproducibility (coefficients of variation around 1% and ICCs > 0.99) for both bacterial species. m-qPCR achieved detection limits and specificity similar to qPCR. An excellent concordance (r = 0.99) was observed between m-qPCR and qPCR for A. actinomycetemcomitans and P. gingivalis without statistical significant differences between both methods Subgingival plaque samples: a high sensitivity (above 80%) and specificity (100%) was obtained with the m-qPCR for both bacteria. The m-qPCR yielded a good concordance in Cq values, showing a good level of agreement between qPCR and m-qPCR.

CONCLUSION

The tested m-qPCR method was successful in the simultaneous quantification of A. actinomycetemcomitans and P. gingivalis, with a high degree of sensitivity and specificity on subgingival plaque samples.

Minimally oxidised LDL as estimated by a new method increase in plasma of type 2 diabetic patients with atherosclerosis or nephropathy

A new sensitive and reproducible method was used to assess LDL oxidative status in Type 2 diabetic patients and control subjects, and the relationships between LDL oxidation and atherosclerosis or nephropathy were determined. LDL oxidation was measured in 35 patients with Type 2 diabetes and 15 control subjects 40 to 60 years of age. Atherosclerosis was assessed by clinical examination, vascular ultrasound, and measurement of intima-media thickness (IMT). Twenty-four hour urinary albumin excretion measurements were performed. Although no differences in lipid values were found between the 22 diabetic patients with atherosclerosis (ATS+) and the 13 without (ATS-), LDL oxidation was significantly higher in ATS+ than ATS- patients (p = 0.009) or control subjects (p = 0.007). LDL oxidation was also increased in the 15 patients with nephropathy (p = 0.003). Oxidation was correlated with IMT in patients with normal to moderately increased IMT ( < or = 1.05 mm). Determination of LDL oxidative status could thus be very helpful in assessing cardiovascular risk, especially in high-risk subjects such as patients with diabetes mellitus.

Sexual harassment of college students: implications for campus health promotion

The authors examined students' perceptions, attitudes, and experiences of sexual harassment by faculty members at a state university, using a sample of 1,139 graduate and undergraduate students. Twenty-six percent (292) of those in the sample responded. The instrument used in the study, adapted from a survey previously used at the University of Iowa, operationally defined eight categories of behavior: sexist comments, undue attention, verbal sexual advances, body language, invitations, physical advances, explicit sexual propositions, and sexual bribery. As many as 8% of the respondents indicated they had experienced the three most extreme forms of harassment--physical advances, explicit sexual propositions, and sexual bribery. Although most students thought they would report sexual harassment, only three incidents of the most extreme forms of sexual harassment were actually reported. Those who experienced harassment indicated that it generally came from one rather than from several faculty members and that it came from both male and female faculty. Twenty-three percent of the men reported experiencing sexist comments, and 5 male students reported they had experienced at least one of the three most extreme forms of sexual harassment. Recommendations for policy revisions and campus health promotion programming that were made following the survey are discussed.