Effect of periodontal therapy on the subgingival microbiota over a 2-year monitoring period. I. Overall effect and kinetics of change

Salivary microbiota reflecting changes in subgingival microbiota

The purpose of this study was to determine whether subgingival microbial changes according to the severity of periodontal disease and following the non-surgical periodontal treatment of periodontitis are reflected in the saliva microbiota. Subgingival and saliva samples were collected from 7 periodontally healthy controls, 14 patients with gingivitis, 12 with moderate periodontitis, and 18 with severe periodontitis. Among subjects who received treatment, seven moderate and seven severe periodontitis patients were selected for post-treatment microbial analysis, and their samples were analyzed at baseline and 6 months after treatment. The V3 and V4 regions of the 16S rRNA gene were sequenced, and correlations of the relative abundance of phyla and health- or periodontitis-dominant species between subgingival plaque and saliva samples were analyzed using Spearman signed-rank tests. Alpha diversity was higher in saliva than subgingival plaque samples, and beta diversity was significantly different between the two samples. However, levels of phyla and most health- or periodontitis-dominant species in salivary microbiota were significantly correlated with those in subgingival plaque. The improvement in clinical parameters following treatment was accompanied by a microbial shift not only in subgingival plaque but also in saliva. The abundance of 2 phyla including Bacteroidetes, 6 genera including Porphyromonas and Treponema, and 11 species including Porphyromonas gingivalis, Tannerella forsythia, and Filifactor alocis was significantly reduced in saliva following treatment. These results indicate that the salivary microbiota can reflect changes in the subgingival microbiota, suggesting that saliva can be used as a diagnostic tool to monitor the periodontal health status of individuals.

IMPORTANCE

The salivary microbiota has attracted increasing attention as a promising method for monitoring periodontal disease. With regard to the pathogenesis of periodontal disease, however, subgingival plaque microbiota is the dominant etiological factor. Although it has been established that periodontopathogenic bacteria exist in saliva and their distribution differs, depending on the severity of the disease, it is necessary to analyze the extent to which the salivary microbiota reflects the subgingival microbiota. This study explored whether subgingival microbial changes according to the severity of periodontal disease and following the non-surgical periodontal treatment of periodontitis are reflected in the saliva microbiota and concluded that the salivary microbiota can reflect changes in the subgingival microbiota. Saliva can be used as a diagnostic tool to monitor the periodontal health status of individuals.

Association of Gum Treatment with Cognitive Decline and Dementia Risk among Older Adults with Periodontal Symptoms: A 12-Year Prospective Cohort Study

INTRODUCTION

This study examines the associations of gum treatment with cognitive decline and dementia risk among older adults with periodontal symptoms in the USA.

METHODS

A cohort of 866 adults aged ≥50 with periodontal symptoms was recruited for the 2008 Health and Retirement Study "Dental Health Experimental Module" and followed until 2020. Cognitive function was assessed with the Telephone Interview for Cognitive Status (TICS). Dementia status was ascertained with the Langa-Weir algorithm based on TICS scores and proxy assessments. Linear mixed-effects model and multivariable Cox regression models were utilized to analyze the associations of gum treatment with cognitive decline and the risk of dementia, respectively.

RESULTS

Of 866 participants (mean age 67.7, 61.4% women), 105 (12.1%) developed dementia with a median follow-up of 9 (IQR, 6-10) years. The dementia incidence rates were lower in the group with gum treatment (7.4 vs. 12.9 per 1,000 person-years). Compared with participants who did not have gum treatment, those with gum treatment experienced a decline in TICS score that was on average 0.025 (95% CI, 0.005-0.044) points less per year and a 38% lower incidence of dementia (hazard ratio, 0.62; 95% CI, 0.41-0.93). These associations were consistent across participants with a different severity of periodontal symptoms and sociodemographic characteristics (age, sex, race, ethnicity, and education) except for income levels.

CONCLUSION

Prompt gum treatment for older adults with periodontal symptoms may be beneficial for their cognitive health.

The oral microbiome of a family including Papillon-Lefèvre-syndrome patients and clinically healthy members

AIMS

The oral microbiota composition of patients diagnosed with Papillon-Lefèvre-syndrome and treated for several years were compared to those existing in the oral cavity of the clinically healthy family members and a cohort of patients having various stages of chronic periodontitis.

MATERIALS AND METHODS

A family with two sisters affected with severe periodontitis and with the typical skin symptoms of Papillon-Lefèvre-syndrome, and symptomless parents and third sibling were investigated. The Patients received periodontal treatment for several years and their oral microbiome was analysed by amplicon sequencing. Data were evaluated by microbial cluster analysis.

RESULTS

The microbiome of the patients with Papillon-Lefèvre-syndrome was predominated with Aggregatibacter actinomycetemcomitans and associated oral periodontopathogens. Although the clinically healthy family members showed no oral disorder, their microbiome resembled that of subjects having mild periodontitis.

CONCLUSIONS

Predominance of A. actinomycetemcomitans in the subgingival microbiome of patients with Papillon-Lefèvre-syndrome suggests that specific treatment strategies directed against this pathobiont may improve the oral health status of the affected individuals.

TRIAL REGISTRATION

The study was conducted in accordance with the Declaration of Helsinki and the ethical permission has been issued by the Human Investigation Review Board of the University of Szeged, Albert Szent-Györgyi Clinical Centre (Permission No. 63/2017-SZTE). September 19, 2017.  https://u-szeged.hu/klinikaikutatas/rkeb-altal-jovahagyott/rkeb-2017 .

Lactic Acid Bacteria in the Human Oral Cavity: Assessing Metabolic Functions Relevant to Oral Health and Disease

Many perceive lactic acid bacteria as beneficial for health. They are recognized for preventing abnormal fermentation and spoilage of ingested foods by producing lactic acid, which aids in gut acidification. Moreover, lactic acid bacteria are extensively employed in food science. In contrast, lactic acid bacteria in the oral cavity are often perceived as pathogenic factors contributing to the development of dental caries. As a consequence, substantial research has been conducted in oral and dental sciences to explore lactic acid bacteria and the oral microbiome. This research primarily involves analyzing bacterial flora, investigating metabolic activities such as acid production, and investigating metabolic regulation within the oral environment. The oral cavity serves as the gateway to the digestive tract and respiratory system, characterized by a constantly fluctuating environment that significantly impacts the metabolic activity of lactic acid bacteria. Hence, when investigating oral lactic acid bacteria, it is crucial to adopt research plans and methodologies that account for these metabolic environment changes. In this section, we present some of the methods employed in our study.

Systemic antibiotics adjuvants to scaling and root planing in type 2 diabetic and periodontitis individuals: Systematic review with network meta-analysis

Targeting inflammatory pathways is considered a common strategy to control type 2 diabetes (T2D) and periodontitis. This overview was to validate systemic antibiotics as an adjuvant to scaling and root planing (SRP) for the treatments of periodontal patients with T2D. Literature searches were conducted using Web of Science, PubMed, Cochrane, and EMBASE. Randomized trials comparing SRP and systemic antibiotics on glycated hemoglobin (HbA1c) and probing pocket depth (PPD) in adults with T2D and periodontitis were analyzed using network meta-analysis and meta-regression. At 3-month postintervention, meta-analyses of 16 studies revealed that SRP and SRP plus systemic antibiotics (SRPa) had similar significant effects in reducing HbA1c levels of - 0.72% and - 0.96% respectively. While SRP and SRPa also, respectively, reduced PPD of - 0.67 and - 0.89 mm, SRPa showed a better reduction than SRP. At 6-month postintervention, meta-analyses of 7 trials revealed that only SRP was effective in reducing HbA1c levels (-0.29%) but not SRPa. Although both SRP and SRPa still significantly reduced PPD by - 0.56 and - 0.81 mm, respectively, there was no difference between them. The current overview suggested that routine SRP alone is highly recommended for patients with T2D and periodontitis, since systemic antibiotics as an adjuvant provide a rather short-term effect.

Association of Dental Diseases and Oral Hygiene Care With the Risk of Heart Failure in Patients With Type 2 Diabetes: A Nationwide Cohort Study

Background To evaluate the association of dental diseases and oral hygiene care with incidence of heart failure (HF) among patients with type 2 diabetes. Methods and Results This study included 173 927 patients with type 2 diabetes aged ≥40 years, who underwent Korean National Health Insurance Service health examinations in 2008 and were followed up until the end of 2017. Hazard ratios (HRs) and 95% CIs for HF were estimated using multivariable Cox proportional hazards regression analysis. During a median follow-up of 9.3 years, 1.94% of participants developed HF. An increased number of missing teeth was associated with a higher risk of HF (P<0.001). HRs of HF increased among individuals with ≥15 missing teeth (HR, 1.37 [95% CI, 1.14-1.64]) compared with those without missing teeth. Decreased risk of HF was observed in individuals with ≥1 time/year of professional dental cleaning (HR, 0.93 [95% CI, 0.87-0.99]) and in those with ≥2 times/d of toothbrushing (HR, 0.90 [95% CI, 0.82-0.98]) compared with those without these practices. While combined presence of missing teeth and periodontal disease (P=0.004) or dental caries (P=0.007) increased HF risk, combined oral hygiene care was associated with further HF risk reduction (P=0.024). Better oral hygiene care was associated with decreased HF risk, even as the number of missing teeth increased (P<0.001). Conclusions Among patients with type 2 diabetes, dental diseases and oral hygiene care are important determinants of HF development. Dental disease management and good oral care may prevent HF in patients with type 2 diabetes.

Newly identified pathogens in periodontitis: evidence from an association and an elimination study

We assessed the level of evidence for the presence of new periodontal pathogens by (i) comparing the occurrence of non-classical periodontal taxa between healthy vs. periodontitis patients (Association study); (ii) assessing the modifications in the prevalence and levels of these species after treatments (Elimination study). In the Association study, we compared the prevalence and levels of 39 novel bacterial species between periodontally healthy and periodontitis patients. In the Elimination study, we analyzed samples from periodontitis patients assigned to receive scaling and root planing alone or with metronidazole+ amoxicillin TID/ 14 days. Levels of 79 bacterial species (39 novel and 40 classic) were assessed at baseline, 3 and 12 months post-therapy. All samples were analyzed using Checkerboard DNA-DNA hybridization. Out of the 39 novel species evaluated, eight were categorized as having strong and four as having moderate association with periodontitis. Our findings suggest strong evidence supporting Lancefieldella rimae, Cronobacter sakazakii, Pluralibacter gergoviae, Enterococcus faecalis, Eubacterium limosum, Filifactor alocis, Haemophilus influenzae, and Staphylococcus warneri, and moderate evidence supporting Escherichia coli, Fusobacterium necrophorum, Spiroplasma ixodetis, and Staphylococcus aureus as periodontal pathogens. These findings contribute to a better understanding of the etiology of periodontitis and may guide future diagnostic and interventional studies.

Influence of Anti-Infective Periodontal Therapy on Subgingival Microbiota Evaluated by Chair-Side Test Compared to qPCR—A Clinical Follow-Up Study

A chair-side test (CST) for five periodontal pathogens (Aggregatibacter actinomycetemcomitans, A.a.; Porphyromonas gingivalis, P.g.; Prevotella intermedia, P.i.; Treponema denticola, T.d.; Tannerella forsythia, T.f.) was compared with qPCR in a previous clinical study on 100 periodontitis patients at first diagnosis (T0). Following non-surgical treatment alone (SRP) or in combination with systemic or local antibiotics, 74 patients (57.4 ± 13.5 years) were again tested at the same sites from 14 to 24 months after T0. Bacterial elimination (%; compared to T0) was determined for each single species and compared between both test systems. In all patients, all five pathogens could not be fully eliminated regardless of therapy or test method. Tested with CST, the mean elimination ranged from 90% for SRP + Amoxicillin/Metronidazole to 59.13% for SRP only. The corresponding qPCR values were 30% and 29.6%. Only A.a. was eradicated in 100% by SRP + Amoxicillin/Metronidazole tested by CST, and it was 80% when qPCR was the test method. CST agreed with qPCR in 98.7% in the detection of A.a., and 74.3%, 78.4%, 73.0%, and 48.7% for P.g., P.i., T.d., and T.f., respectively. Neither conventional treatment nor the additional use of antibiotics—even with the correct indication—could completely eradicate the tested pathogens or prevent pocket reinfection.

Oral Microbiome Is Associated With Incident Hypertension Among Postmenopausal Women

Background Oral microbiota are thought to influence blood pressure (BP) regulation. However, epidemiological data supporting this hypothesis are limited. We examined associations between oral microbiota, BP, and incident hypertension in postmenopausal women. Methods and Results Baseline (1997-2001) examinations were completed on 1215 women (mean age, 63 years) during which subgingival plaque was collected, BP was measured, and medical and lifestyle histories and medication inventory were obtained. Microbiome composition of subgingival plaque was measured using 16S ribosomal RNA gene amplicon sequencing. Baseline measured BP was defined as normotensive (systolic <120 mm Hg and diastolic <80 mm Hg, no BP medication use; n=429); elevated (systolic ≥120 mm Hg or diastolic ≥80 mm Hg, no medication use; n=306); or prevalent treated hypertension (history of physician diagnosis treated with medications; n=480). Incident hypertension (375 cases among 735 without baseline treated hypertension) was defined as newly physician-diagnosed hypertension treated with medication reported on annual health surveys (mean follow-up, 10.4 years). Cross-sectional analysis identified 47 bacterial species (of 245 total) that differed significantly according to baseline BP status (P<0.05). Prospective analysis identified 15 baseline bacterial species significantly (P<0.05) associated with incident hypertension: 10 positively (age-adjusted hazard ratios [HRs], 1.10-1.16 per SD in bacterial abundance) and 5 inversely (HRs, 0.82-0.91) associated. Associations were materially unchanged after further adjustment for demographic, clinical, and lifestyle factors; were similar when analysis was restricted to the normotensive group; and were of consistent magnitudes between strata of baseline age, smoking, body mass index, and BP categories. Conclusions Specific oral bacteria are associated with baseline BP status and risk of hypertension development among postmenopausal women. Research to confirm these observations and elucidate mechanisms is needed.

Nonsurgical Periodontal Treatment Options and Their Impact on Subgingival Microbiota

BACKGROUND

Different periodontal treatment methods (quadrant-wise debridement, scaling and root planing (Q-SRP), full-mouth scaling (FMS), full-mouth disinfection (FMD), and FMD with adjuvant erythritol air-polishing (FMDAP)) were applied in periodontitis patients (stage III/IV). The study objective (substudy of ClinicalTrials.gov Identifier: NCT03509233) was to compare the impact of treatments on subgingival colonization.

METHODS

Forty patients were randomized to the treatment groups. Periodontal parameters and subgingival colonization were evaluated at baseline and 3 and 6 months after treatment.

RESULTS

Positive changes in clinical parameters were recorded in every treatment group during the 3-month follow-up period, but did not always continue. In three groups, specific bacteria decreased after 3 months; however, this was associated with a renewed increase after 6 months (FMS: Porphyromonas gingivalis; FMD: Eubacterium nodatum, Prevotella dentalis; and FMDAP: uncultured Prevotella sp.).

CONCLUSIONS

The benefit of all clinical treatments measured after 3 months was associated with a decrease in pathogenic bacteria in the FMS, FMD, and FMDAP groups. However, after 6 months, we observed further improvement or some stagnation in clinical outcomes accompanied by deterioration of the microbiological profile. Investigating the subgingival microbiota might help appraise successful periodontal treatment and implement individualized therapy.

Toward Personalized Oral Diagnosis: Distinct Microbiome Clusters in Periodontitis Biofilms

Periodontitis is caused by pathogenic subgingival microbial biofilm development and dysbiotic interactions between host and hosted microbes. A thorough characterization of the subgingival biofilms by deep amplicon sequencing of 121 individual periodontitis pockets of nine patients and whole metagenomic analysis of the saliva microbial community of the same subjects were carried out. Two biofilm sampling methods yielded similar microbial compositions. Taxonomic mapping of all biofilms revealed three distinct microbial clusters. Two clinical diagnostic parameters, probing pocket depth (PPD) and clinical attachment level (CAL), correlated with the cluster mapping. The dysbiotic microbiomes were less diverse than the apparently healthy ones of the same subjects. The most abundant periodontal pathogens were also present in the saliva, although in different representations. The single abundant species Tannerella forsythia was found in the diseased pockets in about 16–17-fold in excess relative to the clinically healthy sulcus, making it suitable as an indicator of periodontitis biofilms. The discrete microbial communities indicate strong selection by the host immune system and allow the design of targeted antibiotic treatment selective against the main periodontal pathogen(s) in the individual patients.

Exosomes from dental pulp cells attenuate bone loss in mouse experimental periodontitis

BACKGROUND AND OBJECTIVE

Exosomes are small vesicles secreted from many cell types. Their biological effects largely depend on their cellular origin and the physiological state of the originating cells. Exosomes secreted by mesenchymal stem cells exert therapeutic effects against multiple diseases and may serve as potential alternatives to stem cell therapies. We previously established and characterized human leukocyte antigen (HLA) haplotype homo (HHH) dental pulp cell (DPC) lines from human wisdom teeth. In this study, we aimed to investigate the effect of local administration of HHH-DPC exosomes in a mouse model of periodontitis.

METHODS

Exosomes purified from HHH-DPCs were subjected to particle size analysis, and expression of exosome markers was confirmed by western blotting. We also confirmed the effect of exosomes on the migration of both HHH-DPCs and mouse osteoblastic MC3T3-E1 cells. A mouse experimental periodontitis model was used to evaluate the effect of exosomes in vivo. The morphology of alveolar bone was assessed by micro-computed tomography (μCT) and histological analysis. The effect of exosomes on osteoclastogenesis was evaluated using a co-culture system.

RESULTS

The exosomes purified from HHH-DPCs were homogeneous and had a spherical membrane structure. HHH-DPC exosomes promoted the migration of both human DPCs and mouse osteoblastic cells. The MTT assay showed a positive effect on the proliferation of human DPCs, but not on mouse osteoblastic cells. Treatment with HHH-DPC exosomes did not alter the differentiation of osteoblastic cells. Imaging with µCT revealed that the exosomes suppressed alveolar bone resorption in the mouse model of periodontitis. Although no change was apparent in the dominance of TRAP-positive osteoclast-like cells in decalcified tissue sections upon exosome treatment, HHH-DPC exosomes significantly suppressed osteoclast formation in vitro.

CONCLUSIONS

HHH-DPC exosomes stimulated the migration of human DPCs and mouse osteoblastic cells and effectively attenuated bone loss due to periodontitis.

The effect of adjunctive systemic antibiotics on microbial populations compared to scaling and root planing alone for the treatment of periodontitis: A pilot randomized clinical trial

AIM

To investigate the microbial shift after periodontitis being treated by scaling and root planing (SRP) with or without adjunctive antibiotics, and to assess the relationship between oral microbiota and systemic factors.

METHODS

A 6-month pilot randomized controlled trial recruited 14 subjects with severe periodontitis, divided into test group and control group to receive full-mouth SRP with or without amoxicillin (500mg) and metronidazole (200mg) (t.i.d. 7d). Clinical examination, collection of subgingival plaque and saliva, and blood tests were performed at baseline pre-treatment, three months, and six months post-treatment. The V3V4 region of 16S DNA was sequenced; taxonomic assignment was based on the Human Oral Microbiome Database.

RESULTS

The periodontal condition significantly improved in both groups; the test group showed a greater improvement in plaque index, probing depth, and bleeding index than the control group. The test group demonstrated significantly lower microbial richness and diversity, and less abundant Porphyromonas than the control group in at three months for both subgingival microbiome and salivary microbiome. However, the microbial differences narrowed within six months. The subgingival and salivary microbiota shifted synergistically. Glucose was positively related to subgingival Porphyromonas; mean platelet volume was positively related to subgingival Leptotrichia.

CONCLUSIONS

Systemic administration of amoxicillin and metronidazole along with SRP had an advantage over SRP alone in clinical improvement and infection control in both the subgingival region and saliva three months post-treatment. Microbial advantage nearly disappeared at six months; however, the clinical advantage lasted longer. The use of antibiotics also has potential benefits for systemic inflammation and glucose. This article is protected by copyright. All rights reserved.

Effect of periodontal treatment on preclinical Alzheimer's disease-Results of a trial emulation approach

INTRODUCTION

We investigated the relationship between periodontal treatment and pre-clinical Alzheimer's disease (AD).

METHODS

In this quasi-experimental design, 177 periodontally treated patients from the "Greifswald Approach to Individualized Medicine" cohort, which used the same protocols as the population-based Study of Health in Pomerania TREND (SHIP-TREND), and 409 untreated subjects from SHIP-TREND were analyzed. Subjects were younger than 60 years at the magnetic resonance imaging examination, with a median observation period of 7.3 years. Imaging markers for brain atrophy in late-onset AD and brain aging were used as the outcomes.

RESULTS

Robust to sensitivity analyses, periodontal treatment had a favorable effect on AD-related brain atrophy (-0.41; 95% confidence interval: -0.70 to -0.12; P = .0051), which corresponds to a shift from the 50th to the 37th percentile of the outcome distribution. For brain aging, the treatment effect was uncertain.

CONCLUSION

Periodontitis is related to pre-clinical AD in our population.

Adjunctive effect of locally delivered antimicrobials in periodontitis therapy: A systematic review and meta-analysis

AIM

To answer the following PICOS question: in adult patients with periodontitis, which is the efficacy of adjunctive locally delivered antimicrobials, in comparison with subgingival debridement alone or plus a placebo, in terms of probing pocket depth (PPD) reduction, in randomized clinical trials with at least 6 months of follow-up.

MATERIAL AND METHODS

A systematic search was conducted: 59 papers, reporting 50 different studies, were included. Data on clinical outcome variables changes were pooled and analysed using weighted mean differences (WMDs) and 95% confidence intervals (CI), and prediction intervals (PI), in case of significant heterogeneity.

RESULTS

Statistically significant differences were observed, in 6- to 9-month studies, for PPD (WMD = 0.365, 95% CI [0.262; 0.468], PI [-0.29; 1.01]) and clinical attachment level (CAL) (WMD = 0.263, 95% CI [0.123; 0.403], PI [-0.43; 0.96]). For long-term studies, significant differences were observed for PPD (WMD = 0.190, 95% CI [0.059; 0.321]), but not for CAL. For adverse events, no differences were observed. Results were affected by study design (split-mouth versus parallel studies) and assessment (full- or partial-mouth), as well as by the formulation tested.

CONCLUSIONS

The use adjunctive locally delivered antimicrobials in periodontitis therapy results in statistically significant benefits in clinical outcomes, without relevant side effects.

Putative periodontal pathogens in persisting periodontal pockets of endodontic origin

Background:

The microbial profile of endodontically treated teeth, presenting with a persisting deep periodontal pocket, secondary to a primary endodontic lesion, draining through the gingival crevice, has received very less attention. This observational study was done to evaluate if these sites with persisting pockets of endodontic origin persist because they have acquired bacteria which are considered as putative periodontal pathogens.

Materials and Methods:

Subgingival plaque samples were collected from fifty patients diagnosed with a primary endodontic and a secondary periodontal lesion that persisted even after completion of the root canal treatment. Clinical parameters such as probing pocket depth, clinical attachment level, plaque index, furcation, and tooth mobility were recorded. Real-time polymerase chain reaction was used to determine the possible association between six bacteria, which are frequently associated with periodontal and endodontic lesions.

Results:

The mean cycle threshold value for Treponema denticola (Td) was found to be 33.74, and for Enterococcus faecalis (Ef), it was 34.39. With regard to clinical attachment loss, Td (P < 0.04) and Parvimonas micra (P < 0.05) had a significant correlation.

Conclusion:

Ef (92%) and Td (86%) were found to be most prevalent. Porphyromonas gingivalis and Tannerella forsythia were in minimal to nonexistent levels.

Understanding the microbial components of periodontal diseases and periodontal treatment-induced microbiological shifts

In the mid-1960s the microbial aetiology of periodontal diseases was introduced based on classical experimental gingivitis studies . Since then, numerous studies have addressed the fundamental role that oral microbiota plays in the initiation and progression of periodontal diseases. Recent advances in laboratory identification techniques have contributed to a better understanding of the complexity of the oral microbiome in both health and disease. Modern culture-independent methods such as human oral microbial identification microarray and next-generation sequencing have been used to identify a wide variety of microbial taxa residing in the gingival sulcus and the periodontal pocket. The first theory of the 'non-specific plaque' hypothesis gave rise to the 'ecological plaque' hypothesis and more recently to the 'polymicrobial synergy and dysbiosis hypothesis'. Periodontitis is now considered to be a multimicrobial inflammatory disease in which the various bacterial species within the dental biofilm are in a dysbiotic state and this imbalance favours the establishment of chronic inflammatory conditions and ultimately the destruction of tooth-supporting tissues. Apart from the known putative periodontal pathogens, the whole biofilm community is now considered to play a role in the establishment of inflammation and the initiation and progression of periodontitis in a susceptible host. Treatment is unlikely to eliminate putative pathogens but, when it is thoroughly performed it has the potential to establish a healthy ecosystem by altering the microbial community in numbers and composition and also contribute to the maturation of the host immune response.

Did Omics change periodontal therapy?

The starting point for defining effective treatment protocols is a clear understanding of the etiology and pathogenesis of a condition. In periodontal diseases, this understanding has been hindered by a number of factors, such as the difficulty in differentiating primary pathogens from nonpathogens in complex biofilm structures. The introduction of DNA sequencing technologies, including taxonomic and functional analyses, has allowed the oral microbiome to be investigated in much greater breadth and depth. This article aims to compile the results of studies, using next-generation sequencing techniques to evaluate the periodontal microbiome, in an attempt to determine how far the knowledge provided by these studies has brought us in terms of influencing the way we treat periodontitis. The taxonomic data provided, to date, by published association and elimination studies using next-generation sequencing confirm previous knowledge on the role of classic periodontal pathogens in the pathobiology of disease and include new species/genera. Conversely, species and genera already considered as host-compatible and others less explored were associated with periodontal health as their levels were elevated in healthy individuals and increased after therapy. Functional and transcriptomic analyses also demonstrated that periodontal biofilms are taxonomically diverse, functionally congruent, and highly cooperative. Very few interventional studies to date have examined the effects of treatment on the periodontal microbiome, and such studies are heterogeneous in terms of design, sample size, sampling method, treatment provided, and duration of follow-up. Hence, it is still difficult to draw meaningful conclusions from them. Thus, although OMICS knowledge has not yet changed the way we treat patients in daily practice, the information provided by these studies opens new avenues for future research in this field. As new pathogens and beneficial species become identified, future randomized clinical trials could monitor these species/genera more comprehensively. In addition, the metatranscriptomic data, although still embryonic, suggest that the interplay between the host and the oral microbiome may be our best opportunity to implement personalized periodontal treatments. Therapeutic schemes targeting particular bacterial protein products in subjects with specific genetic profiles, for example, may be the futuristic view of enhanced periodontal therapy.

Microbiome changes in young periodontitis patients treated with adjunctive metronidazole and amoxicillin

BACKGROUND

To our knowledge, to date, no studies have comprehensively assessed the changes occurring in the subgingival microbiome of young patients with periodontitis treated by means of mechanical and antibiotic therapy. Thus, this study aimed to use next-generation sequencing to evaluate the subgingival microbial composition of young patients with severe periodontitis treated with scaling and root planing and systemic metronidazole and amoxicillin.

METHODS

Subgingival samples from healthy individuals and shallow and deep sites from periodontitis patients were individually collected at baseline and 90 days post-treatment. The samples were analyzed using 16S rRNA-gene sequencing (MiSeq-Illumina) and QIIME pipeline. Differences between groups for the microbiological data were determined using principal coordinate analysis (PCoA), linear mixed models, and the PERMANOVA test.

RESULTS

One hundred samples were collected from 10 periodontitis patients and seven healthy individuals. PCoA analysis revealed significant partitioning between pre-and post-treatment samples. No major differences in the composition of the subgingival microbiota were observed between shallow and deep sites, at baseline or at 90-days post-treatment, and the microbiome of both site categories after treatment moved closer in similarity to that observed in periodontal health. Treatment significantly improved all clinical parameters and reduced the relative abundance of classical periodontal pathogens and of Fretibacterium fastidiosum, Eubacterium saphenum, Porphyromonas endodontalis, Treponema medium, Synergistetes, TM7, and Treponema spp, and increased that of Actinomyces, Rothia, Haemophilus, Corynebacterium, and Streptococci spp.

CONCLUSION

Mechanical treatment associated with metronidazole and amoxicillin promoted a beneficial change in the microbiome of young individuals with severe periodontitis.

Effect of Hydrogen Peroxide Photoactivated Decontamination Using 940 nm Diode Laser in Periodontal Treatment: A Pilot Study

Objective: The aim of this study was to compare the antimicrobial effects of hydroxyl radical generation by photoactivation of hydrogen peroxide (H₂O₂) with diode laser (λ = 940 nm) in combination with conventional nonsurgical periodontal therapy. Materials and methods: Thirty-eight patients and 114 teeth were included in this study. The test teeth were randomly assigned to one of the three treatment groups: Group 1 (control group): scaling and root planning (SRP); and the following experimental groups: Group 2: SRP +940 nm diode laser; Group 3: SRP+photoactivation of H₂O₂ with 940 nm diode laser. Clinical examinations, such as periodontal probing depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP) were performed before and after the treatment. The microbiological evaluation included nine periodontal bacterial species investigated by means of real-time polymerase chain reaction assay before and after the treatment. The clinical and bacterial differences were assessed between the investigated groups. Results: The total bacteria load was reduced for all three studied groups and all periodontal indexes (PPD, CAL, and BoP) were improved after each treatment. Group 3 showed significant bacterial reduction of the major periodontal bacteria such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Eubacterium nodatum (p < 0.001) in contrast to the other two groups (p > 0.001). Differences between tested groups showed significant results with regard to Group 3. Conclusions: The synergistic effect of SRP and photoactivation of H₂O₂ with 940 nm diode laser offers an efficient and reliable antimicrobial effect in the nonsurgical periodontal treatment approach.

Salivary microbiota in periodontal health and disease and their changes following nonsurgical periodontal treatment

Purpose

The aims of this study were to examine the salivary microbiota in conditions of periodontal health and disease and to explore microbial changes following nonsurgical periodontal treatment.

Methods

Non-stimulated saliva samples were collected from 4 periodontally healthy participants at baseline and from 8 patients with chronic periodontitis at baseline and 3 months following nonsurgical periodontal therapy. The V3 and V4 regions of the 16S rRNA gene from the DNA of saliva samples were amplified and sequenced. The salivary microbial compositions of the healthy participants and patients with periodontitis prior to and following nonsurgical treatment of periodontitis were compared based on the relative abundance of various taxa.

Results

On average, 299 operational taxonomic units were identified in each sample. The phylogenetic diversity in patients with periodontitis was higher than that in healthy participants and decreased following treatment. The abundance of the phylum Spirochaetes and the genus Treponema in patients with periodontitis was 143- and 134-fold higher than in the healthy control group, respectively, but decreased significantly following treatment. The species that were overabundant in the saliva of patients with periodontitis included the Peptostreptococcus stomatis group, Porphyromonas gingivalis, the Fusobacterium nucleatum group, Parvimonas micra, Porphyromonas endodontalis, Filifactor alocis, and Tannerella forsythia. The phylum Actinobacteria, the genus Streptococcaceae_uc, and the species Streptococcus salivarius group were more abundant in healthy participants than in those with periodontitis. There was a trend toward a decrease in disease-associated taxa and an increase in health-associated taxa following treatment.

Conclusions

Our results revealed differences in the taxa of salivary microbiota between conditions of periodontal health and disease. The taxa found to be associated with health or disease have potential for use as salivary biomarkers for periodontal health or disease.

Integrated hypothesis of dental caries and periodontal diseases

This review considers an integrated hypothesis of dental caries and periodontal diseases that builds on theoretical ecological principles. The backbone of the hypothesis is based on the dynamic stability stage of the oral microbiota, at which intrinsic (mainly saliva and gingival crevicular fluid) and bacterial (mainly metabolic) resilience factors maintain ecological dynamic stability, compatible with clinical health. However, loss of intrinsic resilience factors and/or prolonged changes in the availability of microbial metabolic substrates may shift the ecological balance of the microbiota into either saccharolytic (acidogenic) or amino acid-degrading/proteolytic (alkalinogenic) stages, depending on the nature of the predominant substrates, leading to clinical diseases. Therefore, to maintain and restore the dynamic stability of the oral microbiota, it is necessary to control the drivers of disease, such as salivary flow and influx of bacterial nutrients into the oral cavity. Contrary to conventional wisdom, excessive intake of fermentable carbohydrates may contribute to inflammation in periodontal tissues resulting from hyperglycaemia. An integrated hypothesis emphasizes that both dental caries and periodontal diseases originate in the dynamic stability stage and emerge in response to nutritional imbalances in the microbiota. Periodontal diseases may belong to the sugar driven inflammatory diseases, similar to diabetes, obesity, and cardiovascular diseases.

Effect of compliance during periodontal maintenance therapy on levels of bacteria associated with periodontitis: A 6-year prospective study

BACKGROUND

It is well established that regular compliance during periodontal maintenance therapy (PMT) maintains the stability of periodontal clinical parameters obtained after active periodontal therapy (APT). However, compliance during PMT has not yet been related to subgingival bacterial levels. Thus, this study followed individuals in PMT over 6 years and longitudinally evaluated the effects of compliance on periodontitis-associated bacterial levels and its relation to periodontal status.

METHODS

From a 6-year prospective cohort study with 212 individuals in PMT, 91 were determined to be eligible. From this total, 28 regular compliers (RC) were randomly selected and matched for age and sex with 28 irregular compliers (IC). Complete periodontal examination and microbiological samples were obtained 5 times: T1 (prior to APT), T2 (after APT), T3 (2 years), T4 (4 years), and T5 (6 years). Total bacteria counts and levels of Actinomyces naeslundii, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were evaluated through quantitative polymerase chain reaction.

RESULTS

RC had less tooth loss and better clinical and microbiological conditions over time when compared with IC. IC had higher total bacterial counts and higher levels of T. denticola. Moreover, among IC, total bacterial counts were positively associated with plaque index and bleeding on probing, while levels of A. naeslundii, T. forsythia, and T. denticola were negatively associated with clinical attachment loss (4 to 5 mm) among RC.

CONCLUSIONS

Compliance positively influenced subgingival microbiota and contributed to stability of periodontal clinical status. Regular visits during PMT sustained microbiological benefits provided by APT over a 6-year period.

Subgingival lipid A profile and endotoxin activity in periodontal health and disease

OBJECTIVES

Regulation of lipopolysaccharide (LPS) chemical composition, particularly its lipid A domain, is an important, naturally occurring mechanism that drives bacteria-host immune system interactions into either a symbiotic or pathogenic relationship. Members of the subgingival oral microbiota can critically modulate host immuno-inflammatory responses by synthesizing different LPS isoforms. The objectives of this study were to analyze subgingival lipid A profiles and endotoxin activities in periodontal health and disease and to evaluate the use of the recombinant factor C assay as a new, lipid A-based biosensor for personalized, point-of-care periodontal therapy.

MATERIALS AND METHODS

Subgingival plaque samples were collected from healthy individuals and chronic periodontitis patients before and after periodontal therapy. Chemical composition of subgingival lipid A moieties was determined by ESI-Mass Spectrometry. Endotoxin activity of subgingival LPS extracts was assessed using the recombinant factor C assay, and their inflammatory potential was examined in THP-1-derived macrophages by measuring TNF-α and IL-8 production.

RESULTS

Characteristic lipid A molecular signatures, corresponding to over-acylated, bi-phosphorylated lipid A isoforms, were observed in diseased samples. Healthy and post-treatment samples were characterized by lower m/z peaks, related to under-acylated, hypo-phosphorylated lipid A structures. Endotoxin activity levels and inflammatory potentials of subgingival LPS extracts from periodontitis patients were significantly higher compared to healthy and post-treatment samples.

CONCLUSIONS

This is the first study to consider structure-function-clinical implications of different lipid A isoforms present in the subgingival niche and sheds new light on molecular pathogenic mechanisms of subgingival biofilm communities.

CLINICAL RELEVANCE

Subgingival endotoxin activity (determined by lipid A chemical composition) could be a reliable, bacterially derived biomarker and a risk assessment tool for personalized periodontal care.

Periodontitis and dental scaling associated with pyogenic liver abscess: A population-based case-control study

BACKGROUND AND OBJECTIVES

The purpose of this study was to investigate the relationship between periodontitis, dental scaling (DS) and pyogenic liver abscesses (PLAs).

MATERIAL AND METHODS

A nationwide population-based case-control study was applied using data from the National Health Insurance Research Database in Taiwan. We identified and enrolled 691 PLA patients, who were individually matched by age and sex to 2764 controls.

RESULTS

Conditional logistic regression was applied to estimate adjusted odds ratios (aORs) in patients with exposure to periodontitis and DS before PLA. After adjusting for other confounding factors, periodontitis remained a risk factor for PLA among patients aged 20-40 years, with an aOR of 2.31 (95% confidence interval [CI] = 1.37-3.90, P = .0018). In addition, the average aOR for PLA was significantly lower among patients with one DS (aOR = 0.76, 95% CI = 0.59-0.96) and more than one DS (aOR = 0.61, 95% CI = 0.39-0.95) within 1 year before the index date.

CONCLUSION

According to these results, we concluded that adult patients with periodontitis aged <50 years old are more at risk for PLA than controls, particularly when they have no DS. Moreover, from 20 years of age, non-periodontal patients subjected to at least 2 DS per year are less at risk for PLA than controls.

Do we treat our patients or rather periodontal microbes with adjunctive antibiotics in periodontal therapy? A 16S rDNA microbial community analysis

Empiric antibiotics are often used in combination with mechanical debridement to treat patients suffering from periodontitis and to eliminate disease-associated pathogens. Until now, only a few next generation sequencing 16S rDNA amplicon based publications with rather small sample sizes studied the effect of those interventions on the subgingival microbiome. Therefore, we studied subgingival samples of 89 patients with chronic periodontitis (solely non-smokers) before and two months after therapy. Forty-seven patients received mechanical periodontal therapy only, whereas 42 patients additionally received oral administered amoxicillin plus metronidazole (500 and 400 mg, respectively; 3x/day for 7 days). Samples were sequenced with Illumina MiSeq 300 base pairs paired end technology (V3 and V4 hypervariable regions of the 16S rDNA). Inter-group differences before and after therapy of clinical variables (percentage of sites with pocket depth ≥ 5mm, percentage of sites with bleeding on probing) and microbiome variables (diversity, richness, evenness, and dissimilarity) were calculated, a principal coordinate analysis (PCoA) was conducted, and differential abundance of agglomerated ribosomal sequence variants (aRSVs) classified on genus level was calculated using a negative binomial regression model. We found statistically noticeable decreased richness, and increased dissimilarity in the antibiotic, but not in the placebo group after therapy. The PCoA revealed a clear compositional separation of microbiomes after therapy in the antibiotic group, which could not be seen in the group receiving mechanical therapy only. This difference was even more pronounced on aRSV level. Here, adjunctive antibiotics were able to induce a microbiome shift by statistically noticeably reducing aRSVs belonging to genera containing disease-associated species, e.g., Porphyromonas, Tannerella, Treponema, and Aggregatibacter, and by noticeably increasing genera containing health-associated species. Mechanical therapy alone did not statistically noticeably affect any disease-associated taxa. Despite the difference in microbiome modulation both therapies improved the tested clinical parameters after two months. These results cast doubt on the relevance of the elimination and/or reduction of disease-associated taxa as a main goal of periodontal therapy.

In Vitro Screening of the Antibacterial and Anti-Candida Properties of Crushed Nonantimicrobial Drugs Frequently Prescribed in Nursing Homes

Frail older adults often experience swallowing disorders, prompting nursing staff to crush tablets, open capsules, and mix drugs into their meals or gelled water. However, crushing drugs can lead to pharmacological and gustatory problems. As crushed drugs can stay in prolonged contact with oral microbial biofilm, the current study aimed to investigate their antimicrobial properties. Crushed drugs were diluted in 1 mL of isotonic water and assayed in vitro for: (a) growth inhibition of five bacterial strains and Candida albicans by the diffusion method; (b) inhibition of Streptococcus salivarius and C. albicans biofilm formation; and (c) elimination of a preformed biofilm of S. salivarius and C. albicans after 5-minute contact. Eight of 29 crushed drugs inhibited bacterial and/or fungal growth on agar plates. Twenty-eight of 29 crushed drugs reduced the total biomass when incubated with S. salivarius, and 28 of 29 crushed drugs inhibited C. albicans biofilm formation. Preformed biomass was reduced by ≥25% by seven of 29 drugs. Crushed drugs may unbalance oral ecosystems and contribute to oral inflammation. [Res Gerontol Nurs. 2018; 11(2):82-90.].

Clinical and microbiological effects of egg yolk antibody against Porphyromonas gingivalis as an adjunct in the treatment of moderate to severe chronic periodontitis: a randomized placebo-controlled clinical trial

Purpose

To evaluate the clinical and microbiological effects of the local use of egg yolk immunoglobulin against Porphyromonas gingivalis (anti-P.g. IgY) as an adjunct to scaling and root planing (SRP) in the treatment of moderate to severe chronic periodontitis.

Methods

This was a randomized, placebo-controlled, double-blind trial involving 60 systematically healthy patients with moderate to severe chronic periodontitis. Subjects (n=20/group) were randomly assigned to receive SRP combined with subgingival irrigation of anti-P.g. IgY and anti-P.g. IgY mouthwash, subgingival irrigation of 0.2% chlorhexidine and 0.2% chlorhexidine mouthwash, or subgingival irrigation of placebo and placebo mouthwash for 4 weeks. Probing pocket depth, clinical attachment level, bleeding on probing, and the plaque index were evaluated at baseline and at 4 weeks. Subgingival plaque, gingival crevicular fluid, and saliva were simultaneously collected for microbiological analysis.

Results

Our results showed that anti-P.g. IgY mouthwash was as effective as chlorhexidine at improving clinical parameters over a 4-week period. All the groups showed a significant reduction in levels of P.g. at 4 weeks. No significant difference was observed in the test group when compared to placebo regarding the reduction in the levels of P.g. Anti-P.g. IgY significantly suppressed the numbers of red complex bacteria (RCB) in subgingival plaque and saliva in comparison with placebo. No adverse effects were reported in any of the subjects.

Conclusions

Within the limitations of the study, the present investigation showed that passive immunization with anti-P.g. IgY may prove to be effective in the treatment of chronic periodontitis due to its ability to improve clinical parameters and to reduce RCB. No significant differences were found between the anti-P.g. IgY and placebo groups in the reduction of P.g.

The subgingival periodontal microbiota of the aging mouth

Different mechanisms have been hypothesized to explain the increase in prevalence and severity of periodontitis in older adults, including shifts in the periodontal microbiota. However, the actual impact of aging on the composition of subgingival biofilms remains unclear. In the present article, we provide an overview of the composition of the subgingival biofilm in older adults and the potential effects of age on the oral microbiome. In particular, this review covers the following topics: (i) the oral microbiota of an aging mouth; (ii) the effects of age and time on the human oral microbiome; (iii) the potential impact of inflammaging and immunosenescence in the host-oral microbiota interactions; and (iv) the relationship of the aging oral microbiota and Alzheimer's disease. Finally, we present analyses of data compiled from large clinical studies that evaluated the subgingival microbiota of periodontally healthy subjects and patients with periodontitis from a wide age spectrum (20-83 years of age).

Microbiological outcomes from different periodontal maintenance interventions: a systematic review

This study aimed to investigate the differences in the subgingival microbiological outcomes between periodontal patients submitted to a supragingival control (SPG) regimen as compared to subgingival scaling and root planing performed combined with supragingival debridement (SPG + SBG) intervention during the periodontal maintenance period (PMP). A systematic literature search using electronic databases (MEDLINE and EMBASE) was conducted looking for articles published up to August 2016 and independent of language. Two independent reviewers performed the study selection, quality assessment and data collection. Only human randomized or non-randomized clinical trials with at least 6-months-follow-up after periodontal treatment and presenting subgingival microbiological outcomes related to SPG and/or SPG+SBG therapies were included. Search strategy found 2,250 titles. Among these, 148 (after title analysis) and 39 (after abstract analysis) papers were considered to be relevant. Finally, 19 studies were selected after full-text analysis. No article had a direct comparison between the therapies. Five SPG and 14 SPG+SBG studies presented experimental groups with these respective regimens and were descriptively analyzed while most of the results were only presented graphically. The results showed that both SPG and SPG+SBG protocols of PMP determined stability in the microbiological results along time. Nevertheless, new studies comparing these interventions in PMP are needed, especially if the limitations herein discussed could be better controlled.

Clustering of Subgingival Microbiota Reveals Microbial Disease Ecotypes Associated with Clinical Stages of Periodontitis in a Cross-Sectional Study

Periodontitis is characterized by chronic inflammation associated with alteration of the oral microbiota. In contrast to previous microbiome studies focusing a priori on comparison between extreme phenotypes, our study analyzed a random sample of 85 people. The aim of this study was to link microbial differences to disease’s prevalence and severity. Using next generation sequencing of 16S rRNA amplicons and cluster analysis, we observed that the population can be divided into two major ecotypes: One mainly contained periodontal healthy/mild periodontitis individuals whereas the second ecotype showed a heterogeneous microbial distribution and clustered into three distinct sub-ecotypes. Those sub-ecotypes differed with respect to the frequency of diseased patients and displayed a gradual change in distinct subgingival microbiota that goes along with clinical disease symptoms. In ecotype 2, the subgroup with no clinical signs of disease was linked to an increase of F. nucleatum vincentii but also several other species, while only in “end-stage” dysbiosis classical red complex bacteria gained overweight. Therefore, the microbial disease ecotypes observed in our population can lead to an establishment of an early microbial risk profile for clinically healthy patients.

Cetylpyridinium chloride mouth rinses alleviate experimental gingivitis by inhibiting dental plaque maturation

Oral rinses containing chemotherapeutic agents, such as cetylpyridinium chloride (CPC), can alleviate plaque-induced gingival infections, but how oral microbiota respond to these treatments in human population remains poorly understood. Via a double-blinded, randomised controlled trial of 91 subjects, the impact of CPC-containing oral rinses on supragingival plaque was investigated in experimental gingivitis, where the subjects, after a 21-day period of dental prophylaxis to achieve healthy gingivae, received either CPC rinses or water for 21 days. Within-subject temporal dynamics of plaque microbiota and symptoms of gingivitis were profiled via 16S ribosomal DNA gene pyrosequencing and assessment with the Mazza gingival index. Cetylpyridinium chloride conferred gingival benefits, as progression of gingival inflammation resulting from a lack of dental hygiene was significantly slower in the mouth rinse group than in the water group due to inhibition of 17 gingivitis-enriched bacterial genera. Tracking of plaque α and β diversity revealed that CPC treatment prevents acquisition of new taxa that would otherwise accumulate but maintains the original biodiversity of healthy plaques. Furthermore, CPC rinses reduced the size, local connectivity and microbiota-wide connectivity of the bacterial correlation network, particularly for nodes representing gingivitis-enriched taxa. The findings of this study provide mechanistic insights into the impact of oral rinses on the progression and maturation of dental plaque in the natural human population.

Microbiota-based Signature of Gingivitis Treatments: A Randomized Study

Plaque-induced gingivitis can be alleviated by various treatment regimens. To probe the impacts of various anti-gingivitis treatments on plaque microflora, here a double blinded, randomized controlled trial of 91 adults with moderate gingivitis was designed with two anti-gingivitis regimens: the brush-alone treatment and the brush-plus-rinse treatment. In the later group, more reduction in both Plaque Index (TMQHI) and Gingival Index (mean MGI) at Day 3, Day 11 and Day 27 was evident, and more dramatic changes were found between baseline and other time points for both supragingival plaque microbiota structure and salivary metabonomic profiles. A comparison of plaque microbiota changes was also performed between these two treatments and a third dataset where 50 subjects received regimen of dental scaling. Only Actinobaculum, TM7 and Leptotrichia were consistently reduced by all the three treatments, whereas the different microbial signatures of the three treatments during gingivitis relieve indicate distinct mechanisms of action. Our study suggests that microbiota based signatures can serve as a valuable approach for understanding and potentially comparing the modes of action for clinical treatments and oral-care products in the future.

Amoxicillin Plus Metronidazole Therapy for Patients with Periodontitis and Type 2 Diabetes

The aim of this study was to assess the changes occurring in subgingival biofilm composition and in the periodontal clinical parameters of subjects with periodontitis and type 2 diabetes mellitus (DM) treated by means of scaling and root planing (SRP) only or combined with systemic metronidazole (MTZ) and amoxicillin (AMX). Fifty-eight subjects were randomly assigned to receive SRP only ( n = 29) or with MTZ (400 mg/thrice a day [TID]) and AMX (500 mg/TID) ( n = 29) for 14 d. Six subgingival plaque samples/subject were analyzed by checkerboard DNA–DNA hybridization for 40 bacterial species at baseline and 3 mo, 1 y, and 2 y posttherapy. At 2 y posttherapy, the antibiotic-treated group harbored lower mean proportions (5.5%) of red complex pathogens than the control group (12.1%) ( P < 0.05). The proportions of the Actinomyces species remained stable in the antibiotic group but showed a statistically significant reduction in the control group from 1 to 2 y in subjects achieving a low risk clinical profile for future disease progression (i.e., ≤4 sites with probing depth [PD] ≥5 mm). The test group also had a lower mean number of sites with PD ≥5 mm (3.5 ± 3.4) and a higher percentage of subjects reaching the low risk clinical profile (76%) than the control group (14.7 ± 13.1 and 22%, respectively) ( P < 0.05) at 2 y posttreatment. MTZ + AMX intake was the only significant predictor of subjects achieving the low risk at 2 y (odds ratio, 20.9; P = 0.0000). In conclusion, the results of this study showed that the adjunctive use of MTZ + AMX improves the microbiological and clinical outcomes of SRP in the treatment of subjects with generalized chronic periodontitis and type 2 DM up to 2 y ( ClinicalTrials.gov NCT02135952).

Alterations of the Subgingival Microbiota in Pediatric Crohn's Disease Studied Longitudinally in Discovery and Validation Cohorts

BACKGROUND

Oral manifestations are common in Crohn's disease (CD). Here we characterized the subgingival microbiota in pediatric patients with CD initiating therapy and after 8 weeks to identify microbial community features associated with CD and therapy.

METHODS

Pediatric patients with CD were recruited from The Children's Hospital of Pennsylvania. Healthy control subjects were recruited from primary care or orthopedics clinic. Subgingival plaque samples were collected at initiation of therapy and after 8 weeks. Treatment exposures included 5-ASAs, immunomodulators, steroids, and infliximab. The microbiota was characterized by 16S rRNA gene sequencing. The study was repeated in separate discovery (35 CD, 43 healthy) and validation cohorts (43 CD, 31 healthy).

RESULTS

Most subjects in both cohorts demonstrated clinical response after 8 weeks of therapy (discovery cohort 88%, validation cohort 79%). At week 0, both antibiotic exposure and disease state were associated with differences in bacterial community composition. Seventeen genera were identified in the discovery cohort as candidate biomarkers, of which 11 were confirmed in the validation cohort. Capnocytophaga, Rothia, and TM7 were more abundant in CD relative to healthy controls. Other bacteria were reduced in abundance with antibiotic exposure among CD subjects. CD-associated genera were not enriched compared with healthy controls after 8 weeks of therapy.

CONCLUSIONS

Subgingival microbial community structure differed with CD and antibiotic use. Results in the discovery cohort were replicated in a separate validation cohort. Several potentially pathogenic bacterial lineages were associated with CD but were not diminished in abundance by antibiotic treatment, suggesting targets for additional surveillance.

Effects of azithromycin, metronidazole, amoxicillin, and metronidazole plus amoxicillin on an in vitro polymicrobial subgingival biofilm model

Chronic periodontitis is one of the most prevalent human diseases and is caused by dysbiosis of the subgingival microbiota. Treatment involves primarily mechanical disruption of subgingival biofilms and, in certain cases, adjunctive use of systemic antibiotic therapy. In vitro biofilm models have been developed to study antimicrobial agents targeting subgingival species. However, these models accommodate a limited number of taxa, lack reproducibility, and have low throughput. We aimed to develop an in vitro multispecies biofilm model that mimics subgingival plaque, to test antimicrobial agents. Biofilms were cultivated using the Calgary Biofilm Device and were exposed to amoxicillin (AMX), metronidazole (MTZ), azithromycin (AZM), and AMX-MTZ at four different concentrations for 12, 24, or 36 h. Chlorhexidine (CHX) (0.12%) was used as the positive control. The compositions of the biofilms were analyzed by checkerboard DNA-DNA hybridization, and the percent reduction in biofilm metabolic activity was determined using 2,3,5-triphenyltetrazolium chloride and spectrophotometry. Thirty-five of the 40 species used in the inoculum were consistently recovered from the resulting in vitro biofilms. After 36 h of exposure at the 1:27 dilution, AMX-MTZ reduced metabolic activity 11% less than CHX (q = 0.0207) but 54% more than AMX (q = 0.0031), 72% more than MTZ (q = 0.0031), and 67% more than AZM (q = 0.0008). Preliminary evidence of a synergistic interaction between AMX and MTZ was also observed. In summary, we developed reproducible biofilms with 35 subgingival bacterial species, and our results suggested that the combination of AMX and MTZ had greater antimicrobial effects on these in vitro multispecies biofilms than expected on the basis of the independent effects of the drugs.

Differential benefits of amoxicillin-metronidazole in different phases of periodontal therapy in a randomized controlled crossover clinical trial

BACKGROUND

The specific advantage of administering systemic antibiotics during initial, non-surgical therapy or in the context of periodontal surgery is unclear. This study assesses the differential outcomes of periodontal therapy supplemented with amoxicillin-metronidazole during either the non-surgical or the surgical treatment phase.

METHODS

This is a single-center, randomized placebo-controlled crossover clinical trial with a 1-year follow-up. Eighty participants with Aggregatibacter actinomycetemcomitans-associated moderate to advanced periodontitis were randomized into two treatment groups: group A, antibiotics (500 mg metronidazole plus 375 mg amoxicillin three times per day for 7 days) during the first, non-surgical phase of periodontal therapy (T1) and placebo during the second, surgical phase (T2); and group B, placebo during T1 and antibiotics during T2. The number of sites with probing depth (PD) >4 mm and bleeding on probing (BOP) per patient was the primary outcome.

RESULTS

A total of 11,212 sites were clinically monitored on 1,870 teeth. T1 with antibiotics decreased the number of sites with PD >4 mm and BOP per patient significantly more than without (group A: from 34.5 to 5.7, 84%; group B: from 28.7 to 8.7, 70%; P <0.01). Twenty patients treated with antibiotics, but only eight treated with placebo, achieved a 10-fold reduction of diseased sites (P = 0.007). Consequently, fewer patients of group A needed additional therapy, the mean number of surgical interventions was lower, and treatment time in T2 was shorter. Six months after T2, the mean number of residual pockets (group A: 2.8 ± 5.2; group B: 2.2 ± 5.0) was not significantly different and was sustained over 12 months in both groups.

CONCLUSION

Giving the antibiotics during T1 or T2 yielded similar long-term outcomes, but antibiotics in T1 resolved the disease quicker and thus reduced the need for additional surgical intervention.

Periodontal pathogens and associated factors in aggressive periodontitis: results 5-17 years after active periodontal therapy

OBJECTIVES

To assess the association between presence of periodontal pathogens and recurrence of disease in patients with aggressive periodontitis (AgP) after active periodontal therapy (APT) and further influencing factors.

MATERIAL & METHODS

Microbiological samples were taken from 73 patients with AgP 5-17 years after APT at 292 sites (deepest site per quadrant). Real-time polymerase chain reactions were used to detect the periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Uni- and multivariate analyses evaluated the associations between pathogens and recurrence of disease, smoking and adjunctive antibiotic therapy.

RESULTS

At re-examination A. actinomycetemcomitans could be detected in six patients (8.2%), P. gingivalis in 24 (32.9%), T. forsythia in 31 (42.5%) and T. denticola in 35 (48.0%). Increased levels of T. forsythia and T. denticola at re-examination were significantly associated with recurrence of disease in multivariate analyses (OR: 12.72, p < 0.001; OR 5.55, p = 0.002 respectively). Furthermore, high counts of T. denticola were found in patients with increased percentage of sites with clinical attachment levels (CAL) ≥ 6 mm compared to those with low counts (13.8% versus 3.2%, p = 0.005).

CONCLUSION

In patients with recurrence of disease T. forsythia and T. denticola were detected more frequently and in higher counts. Furthermore, T. denticola was found more frequently in patients with increased CAL.

Altered oral viral ecology in association with periodontal disease

The human oral cavity is home to a large and diverse community of viruses that have yet to be characterized in patients with periodontal disease. We recruited and sampled saliva and oral biofilm from a cohort of humans either periodontally healthy or with mild or significant periodontal disease to discern whether there are differences in viral communities that reflect their oral health status. We found communities of viruses inhabiting saliva and the subgingival and supragingival biofilms of each subject that were composed largely of bacteriophage. While there were homologous viruses common to different subjects and biogeographic sites, for most of the subjects, virome compositions were significantly associated with the oral sites from which they were derived. The largest distinctions between virome compositions were found when comparing the subgingival and supragingival biofilms to those of planktonic saliva. Differences in virome composition were significantly associated with oral health status for both subgingival and supragingival biofilm viruses but not for salivary viruses. Among the differences identified in virome compositions was a significant expansion of myoviruses in subgingival biofilm, suggesting that periodontal disease favors lytic phage. We also characterized the bacterial communities in each subject at each biogeographic site by using the V3 hypervariable segment of the 16S rRNA and did not identify distinctions between oral health and disease similar to those found in viral communities. The significantly altered ecology of viruses of oral biofilm in subjects with periodontal disease compared to that of relatively periodontally healthy ones suggests that viruses may serve as useful indicators of oral health status.

Little is known about the role or the constituents of viruses as members of the human microbiome. We investigated the composition of human oral viral communities in a group of relatively periodontally healthy subjects or significant periodontitis to determine whether health status may be associated with differences in viruses. We found that most of the viruses present were predators of bacteria. The viruses inhabiting dental plaque were significantly different on the basis of oral health status, while those present in saliva were not. Dental plaque viruses in periodontitis were predicted to be significantly more likely to kill their bacterial hosts than those found in healthy mouths. Because oral diseases such as periodontitis have been shown to have altered bacterial communities, we believe that viruses and their role as drivers of ecosystem diversity are important contributors to the human oral microbiome in health and disease states.

Subgingival plaque sampling after combined mechanical and antibiotic nonsurgical periodontal therapy

AIM

This study aimed to make a comparison of two sampling strategies of subgingival plaque after combined mechanical-antibiotic periodontal therapy.

METHODS

Thirty patients (18 female) suffering from aggressive (n = 12) or generalised severe chronic (n = 18) periodontitis were included. Aggregatibacter actinomycetemcomitans had been detected subgingivally in all prior to anti-infective therapy (AT) and combined mechanical-antibiotic AT had been rendered. After AT clinical examinations were performed and subgingival plaque was sampled from the same four sites as prior to AT (ASPRE) as well as from the four deepest sites after AT (DEEP). Per patient two pooled samples (ASPRE/DEEP) were generated and analysed for A. actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola using a commercial 16S rRNA test.

RESULTS

ASPRE failed to detect A. actinomycetemcomitans, DEEP detected A. actinomycetemcomitans only in two patients (7 %). Only for T. forsythia DEEP (53 %) provided higher detection frequencies than ASPRE (27 %; p = 0.005). Detection frequencies of P. gingivalis and T. denticola ranged from 47 to 53 %.

CONCLUSION

After combined mechanical-antibiotic AT sampling the deepest sites revealed higher detection rates. Combined mechanical-antibiotic AT suppresses A. actinomycetemcomitans to a higher extent than P. gingivalis, T. forsythia and T. denticola.

Effect of periodontal therapy on the subgingival microbiota over a 2-year monitoring period. I. Overall effect and kinetics of change

AIM

To examine the 2-year post-therapy kinetics of change in the composition of subgingival biofilms.

MATERIAL AND METHODS

In this study, 178 chronic periodontitis subjects were recruited and clinically monitored at baseline, 3, 6, 12, 18 and 24 months after therapy. All subjects received scaling and root planing and 156 one or more of periodontal surgery, systemically administered amoxicillin + metronidazole or local tetracycline at pockets ≥5 mm. Subgingival biofilm samples taken from each subject at each time point were analysed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. The significance of changes in median species counts over time was sought using the Wilcoxon or Friedman tests and adjusted for multiple comparisons.

RESULTS

Mean counts were significantly reduced from baseline to 2 years for 30 of the 40 taxa. Marked reductions were observed for periodontal pathogens including Tannerella forsythia, Treponema denticola and Eubacterium nodatum. The kinetics of change differed from species to species. When data were subset according to baseline PD, patterns of change in the microbial profiles were generally similar.

CONCLUSION

Periodontal therapy leads to a rapid reduction in periodontal pathogens, followed by a slower reduction in other taxa that can be sustained for at least 2 years.