Microbial mechanisms in the pathogenesis of destructive periodontal diseases: a critical assessment

Subgingival 0.75% boric acid vs 1% povidone-iodine adjunctive to subgingival instrumentation in stage II and III periodontitis-A double-blind randomized clinical trial

PURPOSE

To compare the effects of subgingival irrigation with 0.75% boric acid (BA) and 1% povidone-iodine (PVP-I) as an adjunct to scaling and root planing (SRP) on clinical and microbiologic parameters in the management of patients with periodontitis after a 12-month follow-up.

METHODS

Sixty systemically healthy individuals diagnosed with periodontitis were included in this double-blind randomised clinical trial. The patients were randomly allocated to treatment groups: (1) SRP plus 0.75% BA and (2) SRP plus 1% PVP-I. Whole-mouth periodontals were clinically examined, and the counts of bacteria including Aggregatibacter actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf), Solobacterium moorei (Sm) and Streptococcus salivarius (Ss) were tested by real-time polymerase chain reaction (PCR).

RESULTS

All periodontal parameters and the counts of Aa, Fn, Pg, Td, Tf, Sm and Ss in both groups showed statistically significant reductions at T3, T6 and T12 compared to T0. Whole-mouth or moderate or severe PD and CAL improvements were significantly found in the 0.75% BA group compared to the 1% PVP-I group at T3, T6 and T12. The reduction in Aa or Fn and the reduction in Ss were significantly higher in the 0.75% BA group at T6 and T12 than in the 1% PVP-I group.

CONCLUSION

This study shows that subgingival irrigation with 0.75% BA may be an alternative to 1% PVP-I because it promotes greater PD reductions and CAL gain, particularly up to 12 months after treatment.

MicroRNAs: The Missing Link between Hypertension and Periodontitis?

Cardiovascular diseases are the leading cause of death worldwide, and arterial hypertension is a recognized cardiovascular risk factor that is responsible for high morbidity and mortality. Arterial hypertension is the result of an inflammatory process that results in the remodeling and thickening of the vascular walls, which is associated with an immunological response. Previous studies have attempted to demonstrate the relationship between oral disease, inflammation, and the development of systemic diseases. Currently, the existence of an association between periodontitis and hypertension is a controversial issue because the underlying pathophysiological processes and inflammatory mechanisms common to both diseases are unknown. This is due to the fact that periodontitis is a chronic inflammatory disease that affects the interface of teeth and surrounding tissues. However, the most likely explanation for understanding this association is related to low-grade chronic inflammation. An initial path in the study of the relationship between the mentioned pathologies is the possibility of an epigenetic influence, mediated by noncoding RNAs as microRNAs. Thus, in the present review we describe the role of microRNAs related to arterial hypertension and/or periodontitis. In addition, we identified 13 common microRNAs between periodontitis and hypertension. According to the predictions of the DIANA-mirPath program, they can regulate genes involved in 52 signaling pathways.

Topical treatment of periodontitis using an iongel

Almost 50 % of the U.S. population suffers from oral infections such as periodontitis. Current treatment options for periodontitis include mechanical cleaning procedures, which are performed often under local anesthesia and are time-consuming. Alternate option includes systemic antibiotics which increase the risk of antimicrobial resistance and are not recommended for prolonged usage. Topical treatments of gingiva-based antimicrobial agents have shown limited efficacy due to poor penetration of the therapeutic into deep gingiva where the infection resides. Herein, we report an Iongel of a Deep Eutectic Antimicrobial (IDEA), which simultaneously exhibits deep tissue penetration and antimicrobial activity against P. gingivalis. In vivo studies confirmed that IDEA successfully penetrated into the gingiva and the gingival sulcus, where the pathogens primarily exist, within a short time. In vitro studies confirmed that the dose delivered was adequate to inactivate P. gingivalis biofilm. In vivo studies in a periodontal rat model confirmed that a topical treatment of IDEA eliminated pathogenic bacteria, and the disease progression was significantly suppressed. Safety studies confirmed excellent tolerance to IDEA. Altogether, IDEA offers a promising topical agent against periodontitis.

Dysbiosis From a Microbial and Host Perspective Relative to Oral Health and Disease

The significance of microbiology and immunology with regard to caries and periodontal disease gained substantial clinical or research consideration in the mid 1960's. This enhanced emphasis related to several simple but elegant experiments illustrating the relevance of bacteria to oral infections. Since that point, the understanding of oral diseases has become increasingly sophisticated and many of the original hypotheses related to disease causality have either been abandoned or amplified. The COVID pandemic has reminded us of the importance of history relative to infectious diseases and in the words of Churchill "those who fail to learn from history are condemned to repeat it." This review is designed to present an overview of broad general directions of research over the last 60 years in oral microbiology and immunology, reviewing significant contributions, indicating emerging foci of interest, and proposing future directions based on technical advances and new understandings. Our goal is to review this rich history (standard microbiology and immunology) and point to potential directions in the future (omics) that can lead to a better understanding of disease. Over the years, research scientists have moved from a position of downplaying the role of bacteria in oral disease to one implicating bacteria as true pathogens that cause disease. More recently it has been proposed that bacteria form the ecological first line of defense against "foreign" invaders and also serve to train the immune system as an acquired host defensive stimulus. While early immunological research was focused on immunological exposure as a modulator of disease, the "hygiene hypothesis," and now the "old friends hypothesis" suggest that the immune response could be trained by bacteria for long-term health. Advanced "omics" technologies are currently being used to address changes that occur in the host and the microbiome in oral disease. The "omics" methodologies have shaped the detection of quantifiable biomarkers to define human physiology and pathologies. In summary, this review will emphasize the role that commensals and pathobionts play in their interaction with the immune status of the host, with a prediction that current "omic" technologies will allow researchers to better understand disease in the future.

Surgical Treatment of Furcation Involvement Associated with Recurrence of Aggressive Periodontitis: A Case Report

Here, we report a case of generalized chronic periodontitis with furcation involvement that was treated successfully by means of surgical intervention. The patient was a 43-year-old man requesting treatment for periodontal disease. An initial examination revealed 42% of sites with a probing depth of ≥4 mm and 42.9% of sites with bleeding on probing. The maxillary molars showed varying degrees of furcation involvement. Radiographic examination revealed bone resorption in the molar and mandibular anterior teeth regions. Microbiological examination of subgingival plaque revealed the presence of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia. The patient's oral health-related quality of life (OHRQL) was also assessed. Based on a clinical diagnosis of severe chronic periodontitis, initial periodontal therapy was performed. Plaque control, scaling and root planing, extraction, temporary fixed restoration, occlusal adjustment, and root canal treatment were implemented. Following reevaluation, open flap debridement was performed at selected sites. Root resection was performed on the distal root of #16. Prosthetic treatment was then initiated for recovery of oral function. After confirmation of appropriate occlusion and cleanability, the patient was placed on supportive periodontal therapy. Root resection improved cleanability. This clinical improvement has been adequately maintained over a 2-year period. The patient's OHRQL score showed a slight deterioration during the supportive periodontal therapy OK period, however. This indicates the need for further careful monitoring of periodontal conditions, as well as of how they are perceived by the patient themselves.

Expression of osteoclastogenic and anti-osteoclastogenic cytokines differs in mouse gingiva injected with lipopolysaccharide, peptidoglycan, or both

OBJECTIVE

Bacterial substances in subgingival biofilm evoke alveolar bone resorption. We previously reported that gingival injection of bacterial lipopolysaccharide (LPS) and peptidoglycan (PGN) induced alveolar bone resorption in mice. However, the mechanism by which LPS and PGN induce osteoclast formation has not been investigated. The aim of this study is to clarify the role of osteoclastogenic and anti-osteoclastogenic cytokines in the alveolar bone resorption induced by LPS and PGN.

MATERIALS

LPS from Escherichia coli, PGN from Staphylococcus aureus, or both were injected into the gingiva of mice every 48 h for a total of 13 times. Alveolar bone resorption was assessed histochemically by tartrate-resistant acid phosphatase staining. Expression of the receptor activator of nuclear factor-κB ligand (RANKL), tumor necrosis factor (TNF)-α, interleukin (IL)-17, and IL-10 were analyzed by immunostaining. To analyze the role of these cytokines, RANKL-pretreated mouse bone marrow macrophages were stimulated with LPS, PGN, or LPS + PGN with or without anti-TNF-α antibody, IL-17, or IL-10.

RESULTS

Alveolar bone resorption was induced by both LPS and PGN and exacerbated by LPS + PGN. LPS induced higher RANKL expression than PGN. Expression of TNF-α and IL-10 was correlated with bone resorption. PGN injections induced the strongest expression of IL-17, followed by LPS + PGN and LPS. In an in vitro osteoclastogenesis assay, anti-TNF-α antibody and IL-10 inhibited osteoclast formation, but IL-17 promoted it.

CONCLUSION

LPS, PGN, or LPS + PGN injections induce distinctive expression of TNF-α, IL-10, and IL-17, suggesting that the composition of these bacterial ligands in dental plaque is critical for alveolar bone resorption.

Periodontal Disease and Senescent Cells: New Players for an Old Oral Health Problem?

The recent identification of senescent cells in periodontal tissues has the potential to provide new insights into the underlying mechanisms of periodontal disease etiology. DNA damage-driven senescence is perhaps one of the most underappreciated delayed consequences of persistent Gram-negative bacterial infection and inflammation. Although the host immune response rapidly protects against bacterial invasion, oxidative stress generated during inflammation can indirectly deteriorate periodontal tissues through the damage to vital cell macromolecules, including DNA. What happens to those healthy cells that reside in this harmful environment? Emerging evidence indicates that cells that survive irreparable genomic damage undergo cellular senescence, a crucial intermediate mechanism connecting DNA damage and the immune response. In this review, we hypothesize that sustained Gram-negative bacterial challenge, chronic inflammation itself, and the constant renewal of damaged tissues create a permissive environment for the abnormal accumulation of senescent cells. Based on emerging data we propose a model in which the dysfunctional presence of senescent cells may aggravate the initial immune reaction against pathogens. Further understanding of the role of senescent cells in periodontal disease pathogenesis may have clinical implications by providing more sophisticated therapeutic strategies to combat tissue destruction.

Periodontitis, Low-Grade Inflammation and Systemic Health: A Scoping Review

Background and objectives: Periodontitis is a multifactorial chronic inflammatory infectious disease in which an infection is necessary, but not sufficient, for development of the condition. Individual susceptibility strictly linked to the immune and inflammatory response of the organism must also be present. Low-grade inflammation (LGI) is a systemic status of chronic sub-clinical production of inflammatory factors. This condition represents a risk factor for many chronic diseases including diabetes, cardiovascular disease, cerebrovascular disease, neurodegenerative disease and cancer. This scoping review aims to clarify, summarize and disseminate current knowledge on the possible link between periodontitis, LGI and systemic health. Materials and Methods: PRISMA Extension for Scoping Reviews guidelines were followed. An ad-hoc created keyword string was used to search the electronic databases of PubMed/Medline, Embase, The Cochrane Library and ClinicalTrials.gov. A hand search of specialized journals and their reference lists was also performed. Results: 14 studies that respected eligibility criteria were selected and analyzed. There is emerging evidence of strong links between periodontitis, LGI and systemic health. On the one hand, periodontitis influences the systemic status of LGI and on the other hand, the systemic production of inflammatory factors affects periodontitis with a bidirectional connection. Conclusions: LGI and the subsequent onset of a systemic inflammatory phenotype can be considered the common substrate of many chronic inflammatory diseases including periodontitis, with multiple mutual connections between them. Understanding of the biological principles and mechanisms underlying such a complex interrelationship could lead to significant improvements in the field of personalized diagnostics and therapeutic protocols.

Efficacy of non-surgical treatment accompanied by professional toothbrushing in the treatment of chronic periodontitis in patients with type 2 diabetes mellitus: a randomized controlled clinical trial

Purpose

The present study aimed to evaluate the clinical benefit of additional toothbrushing accompanying non-surgical periodontal treatment on oral and general health in patients with type 2 diabetes mellitus (T2DM).

Methods

We conducted a doubled-blind randomized controlled trial in 60 T2DM patients between June 2013 and June 2014. The patients were randomly assigned to the scaling and root planing (SRP) group; the scaling and root planing with additional toothbrushing (SRPAT) group, in which additional toothbrushing was performed by toothpick methods; or the control group. Microbiological and oral examinations were performed for up to 12 weeks following treatment. Non-surgical treatment was conducted in the experimental groups. The SRP group received scaling and root planing and the SRPAT group received additional toothbrushing with the Watanabe method once a week from the first visit through the fifth visit. The primary outcomes were changes in haemoglobin A1c (or glycated haemoglobin; HbA1c) levels, serum endotoxin levels, and interleukin-1 beta levels. Periodontal health status was measured by periodontal pocket depth, the calculus index, and bleeding on probing (BOP).

Results

Both the SRP and SRPAT groups showed improvements in periodontal health and HbA1c, but the SRPAT group showed significantly less BOP than the SRP group. Furthermore, only the SRPAT group showed a statistically significant decrease in serum endotoxin levels.

Conclusions

Non-surgical periodontal treatment was effective in improving HbA1c and serum endotoxin levels in T2DM patients. Furthermore, non-surgical treatment with additional tooth brushing had a more favourable effect on gingival bleeding management.

Trial Registration

Clinical Research Information Service Identifier: KCT000416

An Evaluation of the Academic Stress’ Affect on Periodontal Tissues

Background/Aim: It has been discussed over the years whether emotional stress might be a risk factor for periodontal diseases. The correlation between periodontal disease and stress can still not be explained. Our aim was to evaluate the effects of academic stress on gingival tissues in a prospective design.

Material and Methods: The study population consisted of randomly selected 40 dental students. Clinical examinations of plaque (PI), gingival (GI) and sulcus bleeding (SBI) indices, probing pocket depth (PPD) and gingival crevicular fluid flow rate were performed along with State-Trait Anxiety Inventory at three different periods of the school year. Measurements were recorded one month before the finals (1st period), during the final exams (2nd period), and two months after the final exams (3rd period).

Results: The changes in mean values of all parameters except plaque and pocket depth between the final and control terms were statistically significant. There was a significant correlation between gingival index and stress, plaque, pocket depth, and sulcus bleeding indices at 1st period. There was a significant correlation between gingival index and crevicular fluid at 2nd period. There was a significant correlation between gingival index and plaque, and sulcus bleeding indices at 3rd period.

Conclusions: The present results support the hypothesis that academic stress is a significant risk factor for gingival and periodontal inflammation.

Cross-sectional association of physical activity and periodontal antibodies

BACKGROUND

The objective of this study was to evaluate the cross-sectional association between physical activity and serum IgG antibodies against selected periodontal microorganisms.

METHODS

The study population consisted of 5,611 randomly selected US adults who participated in the National Health and Nutrition Examination Survey (NHANES) III (1988 to 1994), who were 40 years and older with complete IgG antibody data against 19 oral microorganisms. We used cluster analysis to classify the 19 antibody titers into 4 mutually exclusive groups called "Orange-Red," "Red-Green," "Yellow- Orange," and "Orange-Blue," and calculated cluster scores by summing antibody titer z-scores for each of the four groups. Physical activity was evaluated based on reported frequency and intensity of physical activity conducted in the last month. Participants were grouped into three categories: adequately physically active, inadequately physically active, and inactive. The outcomes were IgG cluster scores with physical activity as the predictor. Multivariable models adjusted for age, sex, race, smoking status, waist circumference, education, poverty-income-ratio, alcohol, and diabetes.

RESULTS

In adjusted models, physical activity was positively associated with the antibodies in the Orange-Blue cluster (E. nodatum, A. naeslundii), a cluster that is associated with healthy periodontal states. The mean differences in cluster scores were 15.2 (95% CI -1.0, 31.4) for Model 3, and 7.0 (95% CI -8.3, 22.3) for Model 4 comparing the sufficiently active group to the inactive group.

CONCLUSIONS

Antibody titers against periodontal microorganisms reflecting good oral health trended higher among physically active individuals, but the results were not statistically significant at the 0.05 level.

Periodontal pathogens promote epithelial-mesenchymal transition in oral squamous carcinoma cells in vitro

Epithelial-mesenchymal transition (EMT) is potentially involved in increasing metastasis of oral squamous cell carcinoma (OSCC). Periodontal pathogens are well-known for their ability to induce intense immune responses and here we investigated whether they are involved in inducing EMT. Cultures of OSCC cell line (H400) were treated separately with heat-killed periodontal pathogens F. nucleatum, or P. gingivalis or E. coli LPS for 8 d. EMT-associated features were assayed using sq-PCR and PCR-arrays, for EMT-related markers, and ELISAs for TGF-β1, TNF-α, and EGF. The migratory ability of cells was investigated using scratch and transwell migration assays. E-cadherin and vimentin expression was assessed using immunofluorescence while Snail activation was detected with immunocytochemistry. In addition, the integrity of the cultured epithelial layer was investigated using transepithelial electrical resistance (TEER). PCR data showed significant upregulation after 1, 5, and 8 d in transcription of mesenchymal markers and downregulation of epithelial ones compared with unstimulated controls, which were confirmed by immunofluorescence. Periodontal pathogens also caused a significant increase in level of all cytokines investigated which could be involved in EMT-induction and Snail activation. Exposure of cells to the bacteria increased migration and the rate of wound closure. Downregulation of epithelial markers also resulted in a significant decrease in impedance resistance of cell monolayers to passage of electrical current. These results suggested that EMT was likely induced in OSCC cells in response to stimulation by periodontal pathogens.

Normal Oral Flora and the Oral Ecosystem

The oral ecosystem comprises the oral flora, so-called oral microbiome, the different anatomic microniches of the oral cavity, and its bathing fluid, saliva. The oral microbiome comprises a group of organisms and includes bacteria, archaea, fungi, protozoa, and viruses. The oral microbiome exists suspended in saliva as planktonic phase organisms or attached to oral surfaces as a plaque biofilm. Homeostasis of the plaque biofilm and its symbiotic relationship with the host is critical for oral health. Disequilibrium or dysbiosis within the plaque biofilms is the initiating event that leads to major oral diseases, such as caries and periodontal disease.

Effect of scaling & root planing on the activity of ALP in GCF & serum of patients with gingivitis, chronic and aggressive periodontitis: A comparative study

INTRODUCTION

Host response and environmental factors are known to modify periodontal status adversely. Presently serum, saliva, and GCF are being investigated for its biochemical constituents. GCF contains array of biochemical factors, offering potential use as a diagnostic or prognostic biomarker of the biologic state of the periodontium in health and disease. Alkaline phosphatase is produced locally in the periodontium and shows positive correlation with disease activity and PD. Present study was designed to analyze the levels of ALP in GCF and serum of patients with gingivitis, chronic & aggressive periodontitis before and after SRP & to compare the difference within the study groups.

METHODS

OPD patients grouped into: Gingivitis, Aggressive periodontitis & chronic periodontitis patients. Clinical parameters recorded for each patient prior to therapy. Pooled GCF samples collected using micro capillary tubes from the deepest pocket sites for each patient and stored at -70° C. Serum samples also collected and stored at -20° C. Each patient was subjected to scaling and root planing with two weeks maintenance recall. After 6 to 8 weeks GCF and serum samples collected again and all clinical parameters rerecorded. GCF and serum samples analyzed for levels of ALP by using para nitro phenol assay for the three groups.

RESULTS

ALP levels in GCF increased significantly during active phase of disease followed by statistically significant reduction after phase I therapy. Baseline levels of ALP in GCF was CP > AP > G with maximum reduction in GCF ALP after SRP in G > CP > AP group.

Effectiveness of systemic antimicrobial therapy in combination with scaling and root planing in the treatment of periodontitis: a systematic review

BACKGROUND

The use of systemic antibiotics in conjunction with scaling and root planing (SRP) may improve the clinical outcome and even could be essential for a successful treatment of periodontitis. However, the effectiveness and clinical safety of this combination of therapy remain unclear. The authors of this study reviewed the available literature related to this hypothesis, evaluating the effectiveness of the use of systemic antimicrobials in combination with SRP versus SRP alone in the treatment of chronic periodontitis (CP) or aggressive periodontitis (AgP).

METHODS

The authors used 3 electronic databases and hand searched articles published from April 2001 through October 2013 in selected journals. The authors selected clinical trials with a minimum of 6 months follow-up during which patients with either CP or AgP had been treated with systemic antibiotics plus SRP in comparison with SRP alone or with placebo. The authors analyzed the gain in clinical attachment level (CAL), reduction in probing pocket depth (PPD), reduction in bleeding on probing (BOP), and patient-related variables (that is, adverse effects).

RESULTS

After the selection process, the authors included 23 clinical trials in this review. Assessment of the quality of the studies revealed the risk of bias as a common finding. Overall, there was a tendency toward improvement of the measured outcomes, CAL, PPD, and BOP in studies for which systemic antibiotics were used as adjunctive therapy with SRP.

CONCLUSION

Owing to the high level of heterogeneity of the studies included in this review, the authors could not establish definitive conclusions and guidelines regarding the use of adjunctive systemic antibiotics. However, within the limitations of this review, the use of systemic antibiotics with SRP may be beneficial for specific populations. Standardized clinical disease diagnostic criteria and additional randomized controlled clinical trials are necessary to verify the effectiveness of the use of adjunctive systemic antimicrobials with SRP.

PRACTICAL IMPLICATIONS

Owing to methodological differences and biases among clinical trials evaluating systemic antibiotics adjunctive to SRP, clinicians should base their decisions to prescribe on the results of weighing both benefits and risks for each patient.

Selective photoantisepsis

BACKGROUND AND OBJECTIVE

Selective killing of pathogens by laser is possible due to the difference in absorption of photon energy by pathogens and host tissues. The optical properties of pathogenic microorganisms are used along with the known optical properties of soft tissues in calculations of the laser-induced thermal response of pathogen colonies embedded in a tissue model. The objective is to define the laser parameters that optimize pathogen destruction and depth of the bactericidal effect.

MATERIALS AND METHODS

The virtual periodontium is a computational model of the optical and time-dependent thermal properties of infected periodontal tissues. The model simulates the periodontal procedure: Laser Sulcular Debridement.¹ Virtual pathogen colonies are placed at different depths in the virtual periodontium to determine the depth for effective bactericidal effects given various laser parameters (wavelength, peak power, pulse duration, scan rate, fluence rate) and differences in pathogen sensitivities.

RESULTS

Accumulated background heat from multiple passes increases the depth of the bactericidal effect. In visible and near-IR wavelengths the large difference in absorption between normal soft tissue and Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) results in selective destruction. Diode laser (810 nm) efficacy and depth of the bactericidal effect are variable and dependent on hemin availability. Both pulsed-Nd:YAG and the 810 nm diode lasers achieve a 2-3 mm deep damage zone for pigmented Pg and Pi in soft tissue without surface damage (selective photoantisepsis). The model predicts no selectivity for the Er:YAG laser (2,940 nm). Depth of the bactericidal effect is highly dependent on pathogen absorption coefficient. Highly sensitive pathogens may be destroyed as deep as 5-6 mm in soft tissue. Short pulse durations enable confinement of the thermal event to the target. Temporal selectivity is achieved by adjusting pulse duration based on target size.

CONCLUSION

The scatter-limited phototherapy model of the infected periodontium is applied to develop a proper dosimetry for selective photoantisepsis. Dosimetry planning is essential to the development of a new treatment modality. Lasers Surg. Med. 48:763-773, 2016. © 2016 Wiley Periodicals, Inc.

Morphological study of proximal root grooves and their influence on periodontal attachment loss

Background:

The etiology of periodontal diseases is multifactorial including both systemic and local causes. Local factors such as grooves on root surfaces contribute a great deal to the causation of periodontal diseases.

Materials and Methods:

Proximal radicular grooves were studied in 150 extracted maxillary and mandibular anterior teeth. Periodontal attachment loss was measured after staining the root surfaces with 0.1% toluidine blue stain. The relationship of the presence and absence of grooves with periodontal attachment loss was also studied.

Results:

The prevalence of proximal root grooves was found to be 86.67%. The prevalence of grooves on maxillary teeth was 43.42% and on mandibular teeth was 56.67%. A greater loss of attachment was present on grooved surfaces than on nongrooved surfaces.

Conclusion:

The proximal radicular grooves present as one of the major etiological factors in periodontal diseases.

Relationship between invasion of the periodontium by periodontal pathogens and periodontal disease: a systematic review

Bacterial invasion of the periodontal tissues has been suggested as a relevant step in the etiopathogenesis of periodontal disease. However, its exact importance remains to be defined. The present systematic review assessed the scientific evidence concerning the relationship between the quality or quantity of periodontal microbiota in periodontal tissues and development of periodontal disease. The databases Medline-PubMed, Cochrane-CENTRAL, ISI Web of Knowledge and SCOPUS were searched, up to January 2014. Studies that reported evaluation of periodontal pathogens invasion on human tissues were selected. The screening of 440 title/abstracts elected 26 papers for full-text reading. Twenty three papers were subsequently excluded because of insufficient data or a study protocol not related to the objectives of this systematic review. All included studies were case-control studies that evaluated intracellular or adherent bacteria to epithelial cells from periodontal pockets versus healthy sulci. Study protocols presented heterogeneity regarding case and control definitions and methodological approaches for microbial identification. No consistent significant differences were found related to the presence/absence or proportion of specific periopathogens across the studies, as only one study found statistically significant differences regarding the presence of A. actinomycetemcomitans (p = 0.043), T. forsythia (P < 0.001), P. intermedia (P < 0.001), C. ochracea (P < 0.001) and C. rectus (P = 0.003) in epithelial cells from periodontal pockets vs. healthy sulci. All studies reported a larger unspecific bacterial load in or on the epithelial cells taken from a diseased site compared to a healthy sulcus. The current available data is of low to moderate quality and inconsistent mainly due to study design, poor reporting and methodological diversity. As so, there is insufficient evidence to support or exclude the invasion by periodontal pathogens as a key step in the etiopathogenesis of periodontal disease. Further research is needed.

16S rRNA based microarray analysis of ten periodontal bacteria in patients with different forms of periodontitis

DNA microarray analysis is a computer based technology, that a reverse capture, which targets 10 periodontal bacteria (ParoCheck) is available for rapid semi-quantitative determination. The aim of this three-year retrospective study was to display the microarray analysis results for the subgingival biofilm samples taken from patient cases diagnosed with different forms of periodontitis. A total of 84 patients with generalized aggressive periodontitis (GAP,n:29), generalized chronic periodontitis (GCP, n:25), peri-implantitis (PI,n:14), localized aggressive periodontitis (LAP,n:8) and refractory chronic periodontitis (RP,n:8) were consecutively selected from the archives of the Oral Microbiological Diagnostic Laboratory. The subgingival biofilm samples were analyzed by the microarray-based identification of 10 selected species. All the tested species were detected in the samples. The red complex bacteria were the most prevalent with very high levels in all groups. Fusobacterium nucleatum was detected in all samples at high levels. The green and blue complex bacteria were less prevalent compared with red and orange complex, except Aggregatibacter actinomycetemcomitas was detected in all LAP group. Positive correlations were found within all the red complex bacteria and between red and orange complex bacteria especially in GCP and GAP groups. Parocheck enables to monitoring of periodontal pathogens in all forms of periodontal disease and can be alternative to other guiding and reliable microbiologic tests.

Association between indices of clinically-defined periodontitis and self-reported history of systemic medical conditions

AIM

The aim of the current research was to investigate whether possible associations exist between indices of clinically-defined periodontitis and several systemic medical conditions in outpatients referred to a special hospital clinic.

METHODS

The study sample consisted of 3360 outpatients aged 45-65 years. Data were collected by means of an oral clinical examination and a self-administered questionnaire. Statistical analysis of the questionnaire items was done with Fisher's exact test and the logistic regression model to assess possible associations between systemic medical conditions as independent variables, and the relative frequency of periodontal pockets ≥5 mm and clinical attachment loss (CAL) of ≥6 mm as dependent variables.

RESULTS

The depth of periodontal pockets was significantly associated with male sex, the presence of vascular disease, hypertension, stroke, heart attack, diabetes mellitus, other endocrine diseases, thyroid disease, respiratory allergies, and rheumatoid arthritis. CAL was significantly associated with the mentioned conditions, and also infective endocarditis and chronic obstructive pulmonary disease, but not other endocrine and thyroid disease.

CONCLUSIONS

The findings confirm the results from previous investigations in which a number of systemic medical conditions were significantly associated with probing pocket depth and/or CAL.

Isolation and identification of Porphyromonas spp. and other putative pathogens from cats with periodontal disease

The purpose of this study was to evaluate the subgingival microbiota and determine the most prevalent periodontal pathogens implicated in feline periodontal disease and to correlate these findings with the clinical periodontal status. Subgingival microbiological samples were taken under sedation from 50 cats with clinical signs of periodontal disease. Pooled paper point samples from 4 selected subgingival sites were cultured on blood agar and on Dentaid-1 medium. Suspected pathogens were identified, subcultured, and preserved. The association between the microbiological findings and the clinical status was studied using correlation coefficients (CC). In addition, cats were stratified in subgroups according to presence of putative pathogens, and comparisons were carried out using unpaired t-test. Three bacterial species were frequently detected including Porphyromonas gulae (86%), Porphyromonas circumdentaria (70%) and Fusobacterium nucleatum (90%). The mean proportion of total flora was high for P. gulae (32.54%), moderate for P. circundentaria (8.82%), and low for F. nucleatum (3.96%). Among the clinical variables, tooth mobility was correlated (CC > 0.50, p < 0.001) with recession, pocket depth, attachment level, gingival index, and calculus index (CC = 0.29, p = 0.04) as well as with total bacterial counts (CC = 0.38, p = 0.006). Cats with more than 10% of P. gulae showed significantly more mobility (p = 0.014) and recession (p = 0.038), and a tendency for deeper probing pocket depths (p = 0.084) and attachment loss (p = 0.087). The results from this cross-sectional study confirmed that P. gulae is the most relevant pathogen in periodontal disease in cats.

Genetic dysbiosis: the role of microbial insults in chronic inflammatory diseases

Thousands of bacterial phylotypes colonise the human body and the host response to this bacterial challenge greatly influences our state of health or disease. The concept of infectogenomics highlights the importance of host genetic factors in determining the composition of human microbial biofilms and the response to this microbial challenge. We hereby introduce the term ‘genetic dysbiosis’ to highlight the role of human genetic variants affecting microbial recognition and host response in creating an environment conducive to changes in the normal microbiota. Such changes can, in turn, predispose to, and influence, diseases such as: cancer, inflammatory bowel disease, rheumatoid arthritis, psoriasis, bacterial vaginosis and periodontitis. This review presents the state of the evidence on host genetic factors affecting dysbiosis and microbial misrecognition (i.e. an aberrant response to the normal microbiota) and highlights the need for further research in this area.

Butyric acid retention in gingival tissue induces oxidative stress in jugular blood mitochondria

Butyric acid (BA) is a major extracellular metabolite produced by anaerobic periodontopathic bacteria and is commonly deposited in the gingival tissue. BA induces mitochondrial oxidative stress in vitro; however, its effects in vivo were never elucidated. Here, we determined the effects of butyric acid retention in the gingival tissues on oxidative stress induction in the jugular blood mitochondria. We established that BA injected in the rat gingival tissue has prolonged retention in gingival tissues. Blood taken at 0, 60, and 180 min after BA injection was used for further analysis. We isolated blood mitochondria, verified its purity, and measured hydrogen peroxide (H2O2), heme, superoxide (SOD), and catalase (CAT) to determine BA effects. We found that H2O2, heme, SOD, and CAT levels all increased after BA injection. This would insinuate that mitochondrial oxidative stress was induced ascribable to BA.

Periodontitis contributes to initiation, progress and aggravation of septic shock; a feasible hypothesis

This hypothesis states that active aggressive periodontitis is an important source of putative endotoxin contributing to the onset of septic shock syndrome [SSS]. Consequently patients with periodontitis may be more prone to developing SSS in predisposing conditions.

Antimicrobial or subantimicrobial antibiotic therapy as an adjunct to the nonsurgical periodontal treatment: a meta-analysis

The use of antibiotics in nonsurgical periodontal treatment is indicated in cases in which scaling and root planing present important limitations. However, their use is controversial due to the secondary effects associated with them and the disagreements regarding their prescription. The aim of this study is to determine the effectiveness of systemic antibiotics in the management of aggressive and chronic periodontitis. The study was based on a search of randomized, controlled clinical trials. Common data were concentrated and evaluated by means of an analysis of variance (ANOVA), and a meta-analysis of the results was performed. The meta-analysis (P < 0.05, 95% confidence interval, post hoc Bonferroni) determined that the supplementation of nonsurgical periodontal therapy with a systemic antibiotic treatment—amoxicillin with clavulanic acid and metronidazole or subantimicrobial dose doxycycline—provides statistically significant results in patients with aggressive or chronic periodontitis under periodontal treatment, whilst increasing the clinical attachment level of the gingiva and reducing periodontal probing depth.

Destructive effects of butyrate on the cell envelope of Helicobacter pylori

Helicobacter pylori can be found in the oral cavity and is mostly detected by the use of PCR techniques. Growth of H. pylori is influenced by various factors in the mouth, such as the oral microflora, saliva and other antimicrobial substances, all of which make colonization of the oral cavity by H. pylori difficult. In the present study, we analysed the effect of the cell supernatant of a representative periodontal bacterium Porphyromonas gingivalis on H. pylori and found that the cell supernatant destroyed the H. pylori cell envelope. As P. gingivalis produces butyric acid, we focused our research on the effects of butyrate and found that it significantly inhibited the growth of H. pylori. H. pylori cytoplasmic proteins and DNA were detected in the extracellular environment after treatment with butyrate, suggesting that the integrity of the cell envelope was compromised and indicating that butyrate has a bactericidal effect on H. pylori. In addition, levels of extracellular H. pylori DNA increased following treatment with the cell supernatant of butyric acid-producing bacteria, indicating that the cell supernatant also has a bactericidal effect and that this may be due to its butyric acid content. In conclusion, butyric acid-producing bacteria may play a role in affecting H. pylori colonization of the oral cavity.

Phagocytic activity of peripheral blood and crevicular phagocytes in health and periodontal disease

Background:

Neutrophils constitute the main phagocytic cell system in mammalian host defense against an infecting agent. Abnormalities in leukocyte number and function are associated with increased susceptibility to periodontal diseases. The purpose of this study is to evaluate the in vitro phagocytic properties of crevicular and peripheral blood neutrophils in healthy and periodontitis subjects.

Patients and Methods:

A total of 30 subjects, that is, 10 patients in each of the following three groups: healthy controls, chronic periodontitis (CP), and localized aggressive periodontitis (LAP), were included in the study. The neutrophils were isolated from the peripheral blood and gingival crevice and tested for phagocytosis of Candida albicans. The percentage of leukocytes with ingested C. albicans was determined by light microscopy.

Results:

A significant reduction in the phagocytic activity of crevicular fluid polymorphonuclear neutrophils (CF-PMN) of LAP subjects (mean: 54.3±7)(P<0.001) was observed, compared to healthy controls (mean: 74.2±9) and chronic periodontitis subjects (mean: 69±9)(P=0.352). The mean percentage of peripheral blood polymorphonuclear neutrophils (PMNs) with phagocytosis of opsonized C. albicans in LAP patients was significantly reduced (mean: 74.9±5)(P<0.0068) compared to the phagocytic activity of neutrophils from controls (mean:82.1±3) and chronic periodontitis subjects (mean: 82.0±5)(P=0.970). There was no significant reduction in the phagocytic activity of CF PMNs (mean: 69±9) (P=0.35) and peripheral blood PMNs (mean: 82.5)(P=0.97) in the chronic periodontitis group when compared to the control group.

Conclusion:

The phagocytic activity of both crevicular and peripheral neutrophils in subjects with periodontitis is altered, increasing the susceptibility to periodontitis. Thus individual susceptibility may be an additional and important modifying factor in the pathogenesis of periodontal disease.

In vitro adherence of Candida albicans isolated from patients with chronic periodontitis

Adherence is considered an extremely important virulence factor in yeast.

OBJECTIVE

The aim of this study was to analyze the adherence to epithelial cells of C. albicans isolated from patients with chronic periodontitis in comparison to healthy patients.

MATERIAL AND METHODS

Candida albicans cells isolated from individuals with chronic periodontitis (n=25) and healthy controls (n=25) were included in this study. Suspensions of C. albicans (10(6) cells/mL) and epithelial cells (10(5) cells/mL) were mixed and incubated at 37ºC for 1 h. The number of yeasts adhered to 25 epithelial cells was counted.

RESULTS

The number of C. albicans cells adhered to epithelial cells was statistically higher in the chronic periodontitis group than in the control group (Student's t-test, p=0.000).

CONCLUSION

The results of the present study suggest a higher Candida adherence of samples isolated from patients with chronic periodontitis.

Detection of selected bacterial species in intraoral sites of patients with chronic periodontitis using multiplex polymerase chain reaction

Objective

The aim of this study was to detect the prevalence of selected bacterial species in intraoral sites of patients with chronic periodontitis (CP) using multiplex polymerase chain reaction (PCR).

Methodology

Samples were collected from the tongue dorsum, buccal mucosa, supragingival and subgingival plaque and saliva of 30 patients with untreated CP. Multiplex PCR was used to determine prevalence rates, which were then compared using a chi-square test. Significance level was set at p<0.05. Mean and standard deviation values were used to evaluate variations in prevalence according to site.

Results

The prevalence of S. mutans was 70% in saliva; 60% in samples collected from the tongue dorsum; 50% in samples collected from the buccal mucosa; 56.5% in the supragingival plaque; and 53.5% in the subgingival plaque. The prevalence of E. faecalis ranged from 3.5% to 13.5% in all intraoral microenvironment. The highest prevalence of P. gingivalis was found in subgingival plaque (53.5%), and of P. intermedia in supragingival plaque (33.5%), subgingival plaque (30%) and tongue dorsum (33.5%). The prevalence of bacteria did not vary significantly among the intraoral sites.

Conclusions

All studied bacteria were identified in intraoral sites. S. mutans, P. gingivalis and P. intermedia had high prevalence rates, but the prevalence of E. faecalis was low. Multiplex PCR proved to be an adequate method for epidemiological studies.

Presence of Helicobacter pylori in supragingival dental plaque of individuals with periodontal disease and upper gastric diseases

BACKGROUND

Helicobacter pylori is a Gram-negative microorganism which is able to colonize the gastric mucosa and is associated with peptic ulcer, gastric carcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Several studies have detected this bacterium in the oral cavity, suggesting it as a potential reservoir. The aim of this study was to investigate the presence of H. pylori in the oral cavity of individuals with periodontal disease and gastric diseases.

METHODS

115 individuals, with mean age 49.6 (±5.8) years, were divided in 4 groups: (A) with gastric diseases and periodontal disease; (B) with gastric diseases and no periodontal disease; (C) without gastric diseases and without periodontal disease, (D) without gastric diseases and with periodontal disease. Supra and subgingival plaque samples were collected from posterior teeth of the individuals with sterile paper points, and prepared for Polymerase Chain Reaction analysis. Fisher's exact test was used for detecting statistical differences between groups (p<0.05).

RESULTS

H. pylori was detected in supragingival plaque of 9/36 (25%) of group A, 1/31 (0.3%) of group B, 0 (0%) of group C and 3/36 (8.3%) of group D. No subgingival samples were positive for H. pylori. There was a statistically higher prevalence of H. pylori in groups A and D when compared to B and C (p<0.05).

CONCLUSION

H. pylori was detected in the supragingival plaque, but not in the subgingival plaque, of individuals with periodontal disease and upper gastric diseases. There was an association between the supragingival colonization of H. pylori and oral hygiene parameters such as the presence of plaque and gingival bleeding.

Experimental pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes

A possible correlation between the presence of discontinuous fringes and high virulence has been previously suggested. The aim of this study was to compare the pathogenicity of Candida albicans and Candida dubliniensis with continuous and discontinuous fringes morphotypes on mice. For C. albicans, two discontinuous fringe morphotype isolates (PN 69, PN 74), two continuous fringe morphotype isolates (N 60, N 33) and one reference strain were used. For C. dubliniensis, three discontinuous fringe morphotype isolates (97487, 97464, 97519), two continuous fringe morphotype isolates (97040, 98026) and one reference strain were used. Swiss male mice were inoculated with a standardised suspension of the microorganisms and observed for 35 days. The pathogenicity of the isolates was analysed according to parameters proposed previously. Three isolates were considered pathogenic: PN 74, N 60 and 98026. Strain N 60 killed the highest amount of mice (80%). Animals inoculated with C. albicans did not show differences on survival estimate. Candida dubliniensis 98026 was more pathogenic than samples 97464 and 97519. On the other hand, the sample 97487 showed a higher pathogenicity when compared with 97040 (Kaplan-Meier test, P = 0.008). Strains with continuous fringe morphotypes were also associated with Candida sp. virulence in vivo.

Comparison of two different microbiological test kits for detection of periodontal pathogens

OBJECTIVE

The aim of this study was to compare the outcome of two different microbiological tests for detection of Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Tannerella forsythia (T.f.) and Treponema denticola (T.d.).

MATERIAL AND METHODS

A total of 69 adult patients with severe chronic (sCP) or aggressive periodontitis (AgP) participated in the study. Microbiological samples were examined for A.a., P.g., T.f. and T.d. using an RNA probe test (PADO) and a real-time polymerase chain reaction test (MERI).

RESULTS

For all periodontal pathogens under investigation, the median bacterial counts detected with PADO were smaller compared to those detected with MERI. P.g., T.f. and T.d. could be found in the majority of all patients with both tests. With MERI, A.a. was detected more often (24.6%) than with PADO (18.8%). Only 10.1% of the patients tested positive for A.a. with both tests.

CONCLUSION

Both tests showed a high percentage of agreement for P.g., T.f. and T.d., but exhibited marked differences in the detection of A.a.

Changes in the structure and density of oral plaque biofilms with increasing plaque age

In common with many biofilms in nature, oral plaque has been shown to have a heterogeneous structure as shown by confocal microscopy. In the present study we have used confocal laser scanning microscopy (CLSM) to determine changes in the structure of plaque biofilms with increasing plaque age. Natural human plaque biofilms were formed using the Leeds in situ device. Plaque biofilms were allowed to form for periods of 2 days, 1 week, 2 weeks and 4 weeks before removal of the devices and immediate imaging using the CLSM. Confocal imaging showed that the biofilms retained their heterogeneous appearance at each of the time points studied but appeared to have a tendency to become somewhat more dense with increasing time. Image analysis demonstrated that the percentage of biomass within each biofilm increased over time, particularly between 2 days and 1 week, and with increasing depth into the biofilms. In addition, using the CLSM we were able to demonstrate changes in the bacterial flora of the biofilms with time, with many more filamentous forms being present at the 2- and 4-week time points.

Periodontal infectogenomics

Multicellular creatures consist of a symbiosis between the host and its colonizing bacteria. The oral cavity may contain as many as 19,000 bacterial phylotypes, while each individual presents a proportion of these microbes. Infectogenomics studies the interaction between host genetic variations and composition of the microbiota. This review introduces the concept of periodontal infectogenomics, defined as the relationship between host genetic factors and the composition of the subgingival microbiota. In particular, the evidence for the effect of genetic variants in neutrophil and cytokine genes and the presence of periodontopathogenic bacteria will be discussed. The influence of genetic factors may affect clearance or persistence of pathogenic bacteria subgingivally, therefore increasing the risk for the development of common pathogenic conditions such as gingivitis and periodontitis, leading to early tooth loss. Mechanisms of interaction between genetic and microbiological factors and prospects for future studies will be discussed.

Interleukin-6 released from fibroblasts is essential for up-regulation of matrix metalloproteinase-1 expression by U937 macrophages in coculture: cross-talking between fibroblasts and U937 macrophages exposed to high glucose

Matrix metalloproteinases (MMPs) play a key role in periodontal disease. Although it is known that macrophages and fibroblasts are co-localized and express MMPs in the diseased periodontal tissue, the effect of interaction between these two cell types on MMP expression has not been well elucidated. Furthermore although it is known that diabetes is associated with accelerated periodontal tissue destruction, it remains unknown whether hyperglycemia, a major metabolic abnormality in diabetes, regulates MMP expression by affecting the cross-talking between fibroblasts and macrophages. In this study, human gingival fibroblasts and U937 macrophages were cocultured in a two-compartment transwell culture system, and the cells were treated with normal or high glucose. We found that coculture of fibroblasts and U937 macrophages led to an augmentation of MMP-1 expression by U937 macrophages, and high glucose further enhanced this augmentation. Similar observations were also made in the coculture of fibroblasts and human primary monocytes. We also found that interleukin 6 (IL-6) released by fibroblasts was essential for the augmentation of MMP-1 expression by U937 macrophages. Furthermore our results showed that high glucose, IL-6, and lipopolysaccharide had a synergistic effect on MMP-1 expression. Finally our study indicated that MAPK pathways and activator protein-1 transcription factor were involved in the coculture- and high glucose-augmented MMP-1 expression. In conclusion, this study demonstrates that IL-6 derived from fibroblasts is essential for MMP-1 up-regulation by cross-talking between fibroblasts and U937 macrophages exposed to high glucose, revealing an IL-6-dependent mechanism in MMP-1 up-regulation.

Laboratory maintenance of Treponema denticola

This unit describes the methods, media, and equipment necessary for routine laboratory culture and handling of the anaerobic oral spirochete Treponema denticola. Topics discussed include nutrient requirements, recommended media formulations, and expected growth kinetics, as well as methods and equipment necessary to maintain anaerobic conditions. An additional protocol on isolation of T. denticola from clinical samples is included.

Salivary malondialdehyde levels in clinically healthy and periodontal diseased individuals

BACKGROUND

Lipid peroxidation (LPO) has been implicated in the pathogenesis of several pathologic disorders, including periodontal disease. Malondialdehyde (MDA) is one of many low molecular weight end products of LPO.

OBJECTIVE

This study was conducted to evaluate salivary MDA levels in generalized chronic periodontitis (GCP) subjects.

MATERIALS AND METHODS

The MDA levels were measured in the saliva of 104 subjects, aged 18-65 years. Three groups with different degrees of severity of GCP were established: 30 early (group 1), 30 moderate (group 2) and 14 severe (group 3). Thirty individuals (aged 25-29 years) with clinically healthy periodontium were served as control. Unstimulated whole saliva samples from study subjects were collected, centrifuged at 3000 g for 15 min and were then stored at -70 degrees C until analysed. The MDA level was determined with 2-thiobarbituric acid by a colorimetric method at 532 nm.

RESULTS

A significant increase in the MDA level existed in the samples obtained from the three groups of patients compared to the control subjects.

CONCLUSION

Increased MDA levels are with closely associated with the severity and patients status of periodontal disease that has not been previously reported. The detection of salivary MDA level may provide additional advantages in elucidating the pathogenesis of periodontal disease.