Periodontal disease diagnosis: current status and future developments

The construction of a microenvironment with the vascular network by co-culturing fibroblasts and endothelial cells

Introduction

Extracellular matrix (ECM) synthesis and deposition in fibroblasts, and vascularization via endothelial cells are essential for successful tissue regeneration. Fibroblasts can produce both ECM, physical support for maintaining homeostasis, and bioactive molecules, such as growth factors and cytokines. Endothelial cells can secrete growth factors and form vascular networks that enable the supply of nutrients and oxygen and remove metabolic products.

Methods

In this study, we focused on combining Human Periodontal Ligament Fibroblasts (HPLF) and Human Umbilical Vein Endothelial Cells (HUVEC) for tissue regeneration in clinical applications.

Results

The fibroblastic and angiogenic phenotypes were promoted in co-culture with HPLF and HUVEC at a ratio of 1:1 compared to HPLF or HUVEC mono-culture. The gene expression of ECM components and angiogenesis-related factors was also enhanced by HPLF/HUVEC co-culture. Despite an apparent increase in the expression of angiogenic factors, the levels of secreted growth factors decreased under co-culture conditions. These data suggest that ECM constructed by HPLF and HUVEC would act as a storage site for growth factors, which can later be released. Our results showed that cell-to-cell interactions between HPLF and HUVEC enhanced collagen synthesis and endothelial network formation, leading to the creation of highly vascularized constructs for periodontal tissue regeneration.

Conclusion

Successful periodontal tissue regeneration requires microenvironmental reconstruction and vascularization, which can be achieved using a co-culture system. In the present study, we found that fibroblastic and angiogenic phenotypes were enhanced by the co-culture of HPLF and HUVEC. The optimal culture conditions (1:1) could potentially accelerate tissue engineering, including ECM synthesis and EC tube formation, and these approaches can improve therapeutic efficacy after transplantation.

The role of extracellular vesicles in periodontitis: pathogenesis, diagnosis, and therapy

Periodontitis is a prevalent disease and one of the leading causes of tooth loss. Biofilms are initiating factor of periodontitis, which can destroy periodontal tissue by producing virulence factors. The overactivated host immune response is the primary cause of periodontitis. The clinical examination of periodontal tissues and the patient's medical history are the mainstays of periodontitis diagnosis. However, there is a lack of molecular biomarkers that can be used to identify and predict periodontitis activity precisely. Non-surgical and surgical treatments are currently available for periodontitis, although both have drawbacks. In clinical practice, achieving the ideal therapeutic effect remains a challenge. Studies have revealed that bacteria produce extracellular vesicles (EVs) to export virulence proteins to host cells. Meanwhile, periodontal tissue cells and immune cells produce EVs that have pro- or anti-inflammatory effects. Accordingly, EVs play a critical role in the pathogenesis of periodontitis. Recent studies have also presented that the content and composition of EVs in saliva and gingival crevicular fluid (GCF) can serve as possible periodontitis diagnostic indicators. In addition, studies have indicated that stem cell EVs may encourage periodontal regeneration. In this article, we mainly review the role of EVs in the pathogenesis of periodontitis and discuss their diagnostic and therapeutic potential.

Recent advances in GTR scaffolds

Periodontitis is a serious chronic inflammatory condition that can cause periodontal tissue deterioration and, eventually, tooth loss. Periodontal regenerative therapy using membranes and bone grafting materials, as well as flap debridement and/or flap curettage, have all been used with varying degrees of clinical effectiveness. Current resorbable and non-resorbable membranes serve as a physical barrier, preventing connective and epithelial tissue down growth into the defect and promoting periodontal tissue regeneration. The "perfect" membrane for use in periodontal regenerative therapy has yet to be created, as these conventional membranes have several structural, mechanical, and bio-functional constraints. We hypothesised in this narrative review that the next-generation of guided tissue and guided bone regeneration (GTR/GBR) membranes for periodontal tissue engineering will be a graded-biomaterials that closely mimics the extracellular matrix.

Synthesis and Incorporation of Quaternary Ammonium Silane Antimicrobial into Self-Crosslinked Type I Collagen Scaffold: A Hybrid Formulation for 3D Printing

Novel 3D-biomaterial scaffold is constructed having a combination of a new quaternary ammonium silane (k21) antimicrobial impregnated in 3D collagen printed scaffolds cross linked with Riboflavin in presence of d-alpha-tocopheryl poly(ethyleneglycol)-1000-succinate. Groups of "0.1% and 0.2% k21", and "0.1% and 0.2% Chlorhexidine (CHX)" are prepared. k21/CHX with neutralized collagen is printed with BioX. Riboflavin is photo-activated and examined using epifluorescence for Aggregatibacter actinomycetemcomitans (7-days). Collagen is examined using TEM and measured for porosity, and shape-fitting. Raman and tandem mass/solid-state are performed with molecular-docking and circular-dichroism. X-ray diffractions, rheological tests, contact angle, and ninhydrin assay are conducted. k21 samples demonstrated collagen aggregates while 0.1% CHX and 0.2% CHX showed irregularities. Porosity of control and "0.1% and 0.2% k21" scaffolds show no differences. Low contact angle, improved elastic-modulus, rigidity, and smaller strain in k21 groups are seen. Bacteria are reduced and strong organic intensities are seen in k21 scaffolds. Simulation shows hydrophobicity/electrostatic interaction. Crosslinking is observed in 0.2% CHX/79% and 0.2% k21/80%. Circular dichroism for k21 are suggestive of triple helix. XRD patterns appear at d = 5.97, 3.03, 2.78, 2.1, and 2.90 A°. 3D-printing of collagen impregnated with quaternary ammonium silane produces a promising scaffold with antimicrobial potency and structural stability.

The recent advances in scaffolds for integrated periodontal regeneration

The periodontium is an integrated, functional unit of multiple tissues surrounding and supporting the tooth, including but not limited to cementum (CM), periodontal ligament (PDL) and alveolar bone (AB). Periodontal tissues can be destructed by chronic periodontal disease, which can lead to tooth loss. In support of the treatment for periodontally diseased tooth, various biomaterials have been applied starting as a contact inhibition membrane in the guided tissue regeneration (GTR) that is the current gold standard in dental clinic. Recently, various biomaterials have been prepared in a form of tissue engineering scaffold to facilitate the regeneration of damaged periodontal tissues. From a physical substrate to support healing of a single type of periodontal tissue to multi-phase/bioactive scaffold system to guide an integrated regeneration of periodontium, technologies for scaffold fabrication have emerged in last years. This review covers the recent advancements in development of scaffolds designed for periodontal tissue regeneration and their efficacy tested in vitro and in vivo. Pros and Cons of different biomaterials and design parameters implemented for periodontal tissue regeneration are also discussed, including future perspectives.

Salivary Metalloproteinase-8 and Metalloproteinase-9 Evaluation in Patients Undergoing Fixed Orthodontic Treatment before and after Periodontal Therapy

(1) Background: Metalloproteinase-8 (MMP-8) and metalloproteinase-9 (MMP-9) are members of a family of proteases of major importance during orthodontic tooth movement. Their levels increase during orthodontic therapy and in periodontally affected tissues. Orthodontic fixed appliances retain dental plaque and can cause gingival inflammation. When gingival inflammation is present, the forces produced during orthodontic tooth movement can aggravate tissue reaction and cause the destruction of supportive periodontal tissue. This study aimed to identify biomarkers that facilitate the assessment of periodontal status during orthodontic treatment. (2) Methods: Our study was conducted on 111 patients who were about to receive fixed orthodontic treatment. We determined the salivary levels of MMP-8 and MMP-9 and bleeding on probing (BOP) before applying the orthodontic fixed appliance (T1), one week after appliance placement (T2), and during orthodontic treatment, one month after non-surgical periodontal treatment (T3). (3) Results: Patients undergoing orthodontic treatment show a significant increase in BOP, MMP-8, and MMP-9 levels one week after orthodontic appliance placement (T2) and a decrease in these parameters one month after periodontal treatment (T3). Statistically significant correlations were found between MMP-8 levels and BOP values at T1, T2, and T3. (4) Conclusion: In our study patients undergoing orthodontic treatment show a significant increase in BOP, MMP-8, and MMP-9 levels one week after orthodontic appliance placement and a decrease in these parameters one month after periodontal treatment. Strong positive statistically significant correlations were found between MMP-8 levels and BOP and medium positive statistically significant correlations between MMP-9 and BOP values before and after orthodontic treatment and periodontal treatment. MMP-8, MMP-9, and BOP could be used to assess the periodontal status of orthodontic patients.

Dental therapists compared with general dental practitioners for undertaking check-ups in low-risk patients: pilot RCT with realist evaluation

Background

Many dental ‘check-ups’ in the NHS result in no further treatment. The patient is examined by a dentist and returned to the recall list for a further check-up, commonly in 6 or 12 months’ time. As the oral health of regular dental attenders continues to improve, it is likely that an increasing number of these patients will be low risk and will require only a simple check-up in the future, with no further treatment. This care could be delivered by dental therapists. In 2013, the body responsible for regulating the dental profession, the General Dental Council, ruled that dental therapists could see patients directly and undertake check-ups and routine dental treatments (e.g. fillings). Using dental therapists to undertake check-ups on low-risk patients could help free resources to meet the future challenges for NHS dentistry.

Objectives

The objectives were to determine the most appropriate design for a definitive study, the most appropriate primary outcome measure and recruitment and retention rates, and the non-inferiority margin. We also undertook a realist-informed process evaluation and rehearsed the health economic data collection tool and analysis.

Design

A pilot randomised controlled trial over a 15-month period, with a realist-informed process evaluation. In parallel, we rehearsed the health economic evaluation and explored patients’ preferences to inform a preference elicitation exercise for a definitive study.

Setting

The setting was NHS dental practices in North West England.

Participants

A total of 217 low-risk patients in eight high-street dental practices participated.

Interventions

The current practice of using dentists to provide NHS dental check-ups (treatment as usual; the control arm) was compared with using dental therapists to provide NHS dental check-ups (the intervention arm).

Main outcome measure

The main outcome measure was difference in the proportion of sites with bleeding on probing among low-risk patients. We also recorded the number of ‘cross-over’ referrals between dentists and dental therapists.

Results

No differences were found in the health status of patients over the 15 months of the pilot trial, suggesting that non-inferiority is the most appropriate design. However, bleeding on probing suffered from ‘floor effects’ among low-risk patients, and recruitment rates were moderately low (39.7%), which suggests that an experimental design might not be the most appropriate. The theory areas that emerged from the realist-informed process evaluation were contractual, regulatory, institutional logistics, patients’ experience and logistics. The economic evaluation was rehearsed and estimates of cost-effectiveness made; potential attributes and levels that can form the basis of preference elicitation work in a definitive study were determined.

Limitations

The pilot was conducted over a 15-month period only, and bleeding on probing appeared to have floor effects. The number of participating dental practices was a limitation and the recruitment rate was moderate.

Conclusions

Non-inferiority, floor effects and moderate recruitment rates suggest that a randomised controlled trial might not be the best evaluative design for a definitive study in this population. The process evaluation identified multiple barriers to the use of dental therapists in ‘high-street’ practices and added real value.

Future work

Quasi-experimental designs may offer more promise for a definitive study alongside further realist evaluation.

Trial registration

Current Controlled Trials ISRCTN70032696.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 9, No. 3. See the NIHR Journals Library website for further project information.

A Prototype Antibody-based Biosensor for Measurement of Salivary MMP-8 in Periodontitis using Surface Acoustic Wave Technology

Periodontitis is an economically important disease which is highly prevalent worldwide. Current diagnostic approaches are time-consuming and require interpretation of multiple aspects of clinical and radiographic assessment. Chair-side monitoring of inflammatory mediators of periodontitis could provide immediate information about disease activity, which can inform patient management. We aimed to develop a novel prototype biosensor to measure salivary matrix metalloproteinase-8 (MMP-8) using specific antibodies and surface acoustic wave (SAW) technology. The analytical performance of the prototype biosensor was compared to standard enzyme-linked immunosorbent assay (ELISA) using unstimulated saliva samples obtained from patients with periodontitis before and after non-surgical treatment (N = 58), patients with gingivitis (N = 54) and periodontally healthy volunteers (N = 65). Receiver operator characteristic (ROC) analysis for distinguishing periodontitis from health revealed an almost identical performance between the sensor and ELISA assays (area under curve values (AUC): ELISA 0.93; SAW 0.89). Furthermore, both analytical approaches yielded readouts which distinguished between heath, gingivitis and periodontitis, correlated identically with clinical measures of periodontal disease and recorded similar post-treatment decreases in salivary MMP-8 in periodontitis. The assay time for our prototype device is 20 minutes. The prototype SAW biosensor is a novel and rapid method of monitoring periodontitis which delivers similar analytical performance to conventional laboratory assays.

Point of Care- A Novel Approach to Periodontal Diagnosis-A Review

Periodontal disease, one of the prevalent oral diseases, is characterized by gingival inflammation and periodontal tissue destruction. Diagnosing this disease is challenging to the clinicians as the disease process is discontinuous and shows periods of exacerbation and remission. Traditional diagnostic methods basically tells about the past tissue destruction so new diagnostic methods are required which is able to detect the active state of the disease, determine the future progression and also estimates the response to the therapy, thereby helping in the better clinical management of the patient. Both saliva and Gingival crevicular fluid (GCF) are believed to be reliable medium to detect the biomarkers which plays a pivotal role in measuring the disease activity. Keeping these observations in mind rapid chairside tests are developed to diagnose periodontal disease called as Point of Care (POC) diagnostics which simplifies diagnosis and helps in improving the prognosis. This review article highlights about the biomarkers used in the diagnosis and throws light on the various available point of care diagnostic devices.

Prevalence and treatment of necrotizing ulcerative gingivitis (NUG) in the British Armed Forces: a case-control study

OBJECTIVES

Necrotizing ulcerative gingivitis (NUG) has been seen in military populations throughout history. This study aims to determine the prevalence, treatment modality and risk factors associated with NUG in the British Armed Forces.

MATERIALS AND METHODS

A whole population dataset of the British Armed Forces was searched to determine cases of NUG during the period 1 January to 31 December 2012. Individual case records were identified, and a case-control study undertaken with data gathered and analysed against a randomised control group, matched for age, sex and service.

RESULTS

A prevalence rate for NUG of 0.11 % was determined against the whole military population. The majority of cases received (alone or in combination) the following: oral hygiene instruction (66.5 %), antibiotics (64.4 %) and a mouthwash (58.1 %). Of the cases, 48.7 % received debridement. Analgesics were only prescribed in 8.4 % of the cases, and smoking cessation advice was only given in 10.7 % of the cases. Analysis of risk factors against the control group showed an increase in odds ratios for diagnosis of NUG of 3.4 (95 % CI 2.0-5.7) for current smokers and 7.3 (95 % CI 1.9-28.0) for individuals with an overall Basic Periodontal Examination (BPE) score of 3.

CONCLUSIONS

Whilst NUG is a rare disease, it is evident from this study that it still occurs within the British Armed Forces. A strong association was shown between NUG and current smokers and those cases with an overall BPE score of 3.

CLINICAL RELEVANCE

This study provides prevalence data for NUG in the British Armed Forces and description of its treatment and associated risk factors. Oral hygiene and smoking must be addressed in patients with NUG and prescribing protocols should be carefully followed.

Identification of biomarkers for periodontal disease using the immunoproteomics approach

Background

Periodontitis is one of the most common oral diseases associated with the host’s immune response against periodontopathogenic infection. Failure to accurately diagnose the stage of periodontitis has limited the ability to predict disease status. Therefore, we aimed to look for reliable diagnostic markers for detection or differentiation of early stage periodontitis using the immunoprotemic approach.

Method

In the present study, patient serum samples from four distinct stages of periodontitis (i.e., mild chronic, moderate chronic, severe chronic, and aggressive) and healthy controls were subjected to two-dimensional gel electrophoresis (2-DE), followed by silver staining. Notably, we consistently identified 14 protein clusters in the sera of patients and normal controls.

Results

Overall, we found that protein levels were comparable between patients and controls, with the exception of the clusters corresponding to A1AT, HP, IGKC and KNG1 (p < 0.05). In addition, the immunogenicity of these proteins was analysed via immunoblotting, which revealed differential profiles for periodontal disease and controls. For this reason, IgM obtained from severe chronic periodontitis (CP) sera could be employed as a suitable autoantibody for the detection of periodontitis.

Discussion

Taken together, the present study suggests that differentially expressed host immune response proteins could be used as potential biomarkers for screening periodontitis. Future studies exploring the diagnostic potential of such factors are warranted.

Alveolar bone-loss area localization in periodontitis radiographs based on threshold segmentation with a hybrid feature fused of intensity and the H-value of fractional Brownian motion model

BACKGROUND AND OBJECTIVE

Periodontitis involves progressive loss of alveolar bone around the teeth. Hence, automatic alveolar bone-loss (ABL) measurement in periapical radiographs can assist dentists in diagnosing such disease. In this paper, we propose an effective method for ABL area localization and denote it as ABLIfBm.

METHOD

ABLIfBm is a threshold segmentation method that uses a hybrid feature fused of both intensity and texture measured by the H-value of fractional Brownian motion (fBm) model, where the H-value is the Hurst coefficient in the expectation function of a fBm curve (intensity change) and is directly related to the value of fractal dimension. Adopting leave-one-out cross validation training and testing mechanism, ABLIfBm trains weights for both features using Bayesian classifier and transforms the radiograph image into a feature image obtained from a weighted average of both features. Finally, by Otsu's thresholding, it segments the feature image into normal and bone-loss regions.

RESULTS

Experimental results on 31 periodontitis radiograph images in terms of mean true positive fraction and false positive fraction are about 92.5% and 14.0%, respectively, where the ground truth is provided by a dentist. The results also demonstrate that ABLIfBm outperforms (a) the threshold segmentation method using either feature alone or a weighted average of the same two features but with weights trained differently; (b) a level set segmentation method presented earlier in literature; and (c) segmentation methods based on Bayesian, K-NN, or SVM classifier using the same two features.

CONCLUSION

Our results suggest that the proposed method can effectively localize alveolar bone-loss areas in periodontitis radiograph images and hence would be useful for dentists in evaluating degree of bone-loss for periodontitis patients.

Detection and diagnosis of periodontal conditions amenable to prevention

Gingivitis and chronic periodontitis are highly prevalent chronic inflammatory diseases. Gingivitis affects the majority of people, and advanced periodontitis is estimated to affect 5-15% of adults. The detection and diagnosis of these common diseases is a fundamentally important component of oral health care. All patients should undergo periodontal assessment as part of routine oral examination. Periodontal screening using methods such as the Basic Periodontal Examination/Community Periodontal Index or Periodontal Screening Record should be performed for all new patients, and also on a regular basis as part of ongoing oral health care. If periodontitis is identified, full periodontal assessment is required, involving recording of full mouth probing and bleeding data, together with assessment of other relevant parameters such as plaque levels, furcation involvement, recession and tooth mobility. Radiographic assessment of alveolar bone levels is driven by the clinical situation, and is required to assess bone destruction in patients with periodontitis. Risk assessment (such as assessing diabetes status and smoking) and risk management (such as promoting smoking cessation) should form a central component of periodontal therapy. This article provides guidance to the oral health care team regarding methods and frequencies of appropriate clinical and radiographic examinations to assess periodontal status, to enable appropriate detection and diagnosis of periodontal conditions.

Periodontal care as a fundamental step for an active and healthy ageing

In the industrialized part of the world, an increasing number of people live the old age without too many restrictions due to illness or physiological impairment. This group is known as the young elderly. On the contrary, a consistent part of seniors develops a greater number of medical conditions and become more and more dependent, these are the old elderly. The first cause of tooth lost in industrialized word is periodontitis that generally strikes people older than 40 years and determines serious detriment of the stomatognatic organ. Smoking and stress are risk factors for periodontitis that are common and shared between young, adult, and older age. Diabetes mellitus, obesity, and osteoporosis are very frequent pathological situations in older age. They have been identified as cofactors in the progression of periodontitis. Many dental associations recognize the importance of continued research on oral fluids diagnostics and welcome the development of rapid point-of-care tests providing accurate measurements of clinically validated biomarkers. At present, well-studied molecules associated with host response factors and with derived tissue destruction mediators have been proposed as diagnostic biomarkers for periodontitis detected in the oral fluids.

Predictive, preventive, personalised and participatory periodontology: 'the 5Ps age' has already started

An impressive progress in dentistry has been recorded in the last decades. In order to reconsider guidelines in dentistry, it is required to introduce new concepts of personalised patient treatments: the wave of predictive, preventive and personalised medicine is rapidly incoming in dentistry. Worldwide dentists have to make a big cultural effort in changing the actual 'reactive' therapeutic point of view, belonging to the last century, into a futuristic 'predictive' one. The first cause of tooth loss in industrialised world is periodontitis, a Gram-negative anaerobic infection whose pathogenesis is genetically determined and characterised by complex immune reactions. Chairside diagnostic tests based on saliva, gingival crevicular fluid and cell sampling are going to be routinely used by periodontists for a new approach to the diagnosis, monitoring, prognosis and management of periodontal patients. The futuristic '5Ps' (predictive, preventive, personalised and participatory periodontology) focuses on early integrated diagnosis (genetic, microbiology, host-derived biomarker detection) and on the active role of the patient in which networked patients will shift from being mere passengers to responsible drivers of their health. In this paper, we intend to propose five diagnostic levels (high-tech diagnostic tools, genetic susceptibility, bacterial infection, host response factors and tissue breakdown-derived products) to be evaluated with the intention to obtain a clear picture of the vulnerability of a single individual to periodontitis in order to organise patient stratification in different categories of risk. Lab-on-a-chip (LOC) technology may soon become an important part of efforts to improve worldwide periodontal health in developed nations as well as in the underserved communities, resource-poor areas and poor countries. The use of LOC devices for periodontal inspection will allow patients to be screened for periodontal diseases in settings other than the periodontist practice, such as at general practitioners, general dentists or dental hygienists. Personalised therapy tailored with respect to the particular medical reality of the specific stratified patient will be the ultimate target to be realised by the 5Ps approach. A long distance has to be covered to reach the above targets, but the pathway has already been clearly outlined.

Evaluation of cross-linked chitosan microparticles containing metronidazole for periodontitis treatment

The aims of this study were to find the optimal formulation for the preparation of metronidazole-loaded chitosan microparticles (MTZ-MPs) via an emulsion cross-linking process, and to compare the in vitro release of MTZ from hydrogels and films containing the drug in forms of MTZ-MPs and raw powders. The effects of emulsifier type and concentration, amount of cross-linking agent, cross-linking time, drug:chitosan ratio, form of drug adding and washing method on the properties of the MTZ-MPs were investigated. The results indicated that the optimal conditions for round and free-flowing MTZ-MPs with a high percentage of entrapped drug and preferable release profile were 1% of Span80 in soybean oil, 5% of glutaraldehyde based on chitosan solution, 30 min of cross-linking time, 1:1 drug:chitosan ratio, drug adding in form of ethanol solution and washing with hexane only. MTZ-MPs prepared from the optimal formulation were incorporated in mucoadhesive hydrogel and film. The release profiles of the drug from hydrogel and film containing MTZ-MPs were in prolong pattern compared with those containing drug powders. However, the hydrogels exhibited higher preferable pattern of release profile than the films. Therefore, the hydrogel containing MTZ-MPs was possible to be further clinically investigated for peridontitis treatment.

What do 'omic technologies have to offer periodontal clinical practice in the future?

BACKGROUND AND OBJECTIVE

Periodontal diseases are the most common chronic inflammatory diseases of humans and a major cause of tooth loss. Inflammatory periodontitis is also a complex multifactorial disease involving many cell types, cell products and interactions. It is associated with a dysregulated inflammatory response, which fails to resolve, and which also fails to re-establish a beneficial periodontal microbiota. There is a rich history of biomarker research within the field of periodontology, but exemplary improvements in analytical platform technologies offer exciting opportunities for discovery. These include the 'omic technologies, such as genomics, transcriptomics, proteomics and metabolomics, which provide information on global scales that can match the complexity of the disease. This narrative review focuses on the recent advances made in in vivo human periodontal research by use of 'omic technologies.

MATERIAL AND METHODS

The Medline database was searched to identify articles currently available on 'omic technologies with regard to periodontal research.

RESULTS

One hundred and sixty-one articles focusing on biomarkers of and 'omic advances in periodontal research were analysed for their contributions to the understanding of periodontal diseases.

CONCLUSION

The data generated by the use of 'omic technologies have huge potential to inform paradigm shifts in our understanding of periodontal diseases, but data management, analysis and interpretation require a thoughtful and systematic bioinformatics approach, to ensure meaningful conclusions can be made.

Activation of the neutrophil respiratory burst by plasma from periodontitis patients is mediated by pro-inflammatory cytokines

AIM

To determine the effect of periodontitis patients' plasma on the neutrophil oxidative burst and the role of albumin, immunoglobulins (Igs) and cytokines.

MATERIALS AND METHODS

Plasma was collected from chronic periodontitis patients (n=11) and periodontally healthy controls (n=11) and used with/without depletion of albumin and Ig or antibody neutralization of IL-8, GM-CSF or IFN-α to prime/stimulate peripheral blood neutrophils, isolated from healthy volunteers. The respiratory burst was measured by lucigenin-dependent chemiluminescence. Plasma cytokine levels were determined by ELISA.

RESULTS

Plasmas from patients were significantly more effective in both directly stimulating neutrophil superoxide production and priming for subsequent formyl-met-leu-phe (fMLP)-stimulated superoxide production than plasmas from healthy controls (p<0.05). This difference was maintained after depletion of albumin and Ig. Plasma from patients contained higher mean levels of IL-8, GM-CSF and IFN-α. Individual neutralizing antibodies against IL-8, GM-CSF or IFN-α inhibited the direct stimulatory effect of patients' plasma, whereas the ability to prime for fMLP-stimulated superoxide production was only inhibited by neutralization of IFN-α. The stimulating and priming effects of control plasma were unaffected by antibody neutralization.

CONCLUSIONS

This study demonstrates that plasma cytokines may have a role in inducing the hyperactive (IL-8, GM-CSF, IFN-α) and hyper-reactive (IFN-α) neutrophil phenotype seen in periodontitis patients.

Fluid exudates from inflamed bone-anchored hearing aids demonstrate elevated levels of cytokines and biomarkers of tissue and bone metabolism

OBJECTIVE

The purpose of the current study was to determine the presence of biomarkers of tissue and bone metabolism and 10 cytokines within the fluid exudate from around bone anchored hearing aids (BAHAs), with a view to understanding the mechanisms of peri-BAHA inflammation.

STUDY DESIGN

Fluid exudate from around BAHAs was collected from volunteers (n = 10) with inflammation and controls (n = 10) without inflammation around the BAHA.

SETTING

Studies of periodontitis and dental peri-implantitis have demonstrated that fluid exudate, arising from the hard tissue-soft tissue junction, is increased during disease; this fluid contains biomarkers of tissue metabolism, bone metabolism and inflammation.

PATIENTS

Volunteers were recruited from the Queen Elizabeth Hospital, Birmingham, UK and New Cross Hospital, Wolverhampton, UK.

INTERVENTIONS

This was an observational study and no interventions were carried out as part of the study.

MAIN OUTCOME MEASURE

Biomarkers of tissue metabolism (MMP9, TIMP1 and 2), bone metabolism (RANKL and OPG) and cytokines (GM-CSF, interferon (IFN)-*, IL-1A, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10 and TNF>) were measured in the fluid samples by Luminex multianalyte assay.

RESULTS

Volumes of fluid exudate were significantly higher (p < 0.05) at sites of inflammation than from un-inflamed tissues surrounding BAHAs. IL-1*, IL-6, IL-8, TNF*, MMP9, TIMP1 and 2 were found in both inflamed and un-inflamed samples and levels were significantly higher in samples from inflamed sites. RANKL, IFN*, IL-2, IL-4, and GM-CSF were detected only at inflamed sites whereas OPG, IL-5 and IL-10 were not detected in any samples.

CONCLUSION

These data demonstrate that peri-BAHA tissues showing clinical signs of inflammation are associated with increased fluid exudate, which contains elevated levels of key biomarkers of inflammation and a biomarker profile that is consistent with increased tissue and bone remodeling around BAHAs.

Gingipains from Porphyromonas gingivalis increase the chemotactic and respiratory burst-priming properties of the 77-amino-acid interleukin-8 variant

Porphyromonas gingivalis, a gram-negative anaerobe which is implicated in the etiology of active periodontitis, secretes degradative enzymes (gingipains) and sheds proinflammatory mediators (e.g., lipopolysaccharides [LPS]). LPS triggers the secretion of interleukin-8 (IL-8) from immune (72-amino-acid [aa] variant [IL-8(72aa)]) and nonimmune (IL-8(77aa)) cells. IL-8(77aa) has low chemotactic and respiratory burst-inducing activity but is susceptible to cleavage by gingipains. This study shows that both R- and K-gingipain treatments of IL-8(77aa) significantly enhance burst activation by fMLP and chemotactic activity (P < 0.05) but decrease burst activation and chemotactic activity of IL-8(72aa) toward neutrophil-like HL60 cells and primary neutrophils (P < 0.05). Using tandem mass spectrometry, we have demonstrated that R-gingipain cleaves 5- and 11-aa peptides from the N-terminal portion of IL-8(77aa) and the resultant peptides are biologically active, while K-gingipain removes an 8-aa N-terminal peptide yielding a 69-aa isoform of IL-8 that shows enhanced biological activity. During periodontitis, secreted gingipains may differentially affect neutrophil chemotaxis and activation in response to IL-8 according to the cellular source of the chemokine.

Adjunctive subantimicrobial dose doxycycline in the management of institutionalised geriatric patients with chronic periodontitis*

OBJECTIVE

To assess the efficacy of subantimicrobial dose doxycycline (SDD; 20 mg doxycycline twice daily) as an adjunct to scaling and root planing (SRP) in the treatment of moderate-severe chronic periodontitis (CP) in institutionalised elderly patients aged 65 years or older.

BACKGROUND

Previous studies have shown that SDD is of clinical benefit in the treatment of CP. However, the benefits of SDD in geriatric populations (65+ years) have not been determined.

MATERIAL AND METHODS

A 9-month, double-blind, randomised, placebo-controlled pilot study was conducted. 24 institutionalised geriatric patients (65 years or older) with evidence of CP manifested by baseline clinical attachment levels (CAL) 5-9 mm, probing depths (PD) 4-9 mm and bleeding on probing (BOP) were recruited. At baseline, patients were treated by a standardised episode of SRP, and randomised to receive either adjunctive SDD or placebo. Full mouth PD and CAL were measured using the manual UNC-15 periodontal probe at 3, 6, and 9 months post-baseline to assess the response to treatment. Periodontal sites were stratified by baseline PD value: sites with PD 4-5 mm were considered moderately diseased and sites with PD > or = 6 mm severely diseased.

RESULTS

The SRP + placebo resulted in PD reductions similar to those reported previously in the literature. At all time-points and in both moderate and deep sites, SRP + SDD resulted in significantly greater PD reductions relative to baseline than SRP + placebo. At month 9, in moderate sites, mean PD reductions of 1.57 +/- 0.11 mm were reported in the adjunctive SDD group, compared with 0.63 +/- 0.11 mm in the adjunctive placebo group (p < 0.001). In deep sites at month 9, mean PD reductions of 3.22 +/- 0.29 mm were reported in the adjunctive SDD group, compared with 0.98 +/- 0.31 mm in the adjunctive placebo group (p < 0.05). Similar improvements were observed for CAL in the SDD group compared with the placebo group. Significantly lower BOP scores were also recorded at month 9 in the SDD group (7.5%) compared with the placebo group (71.2%) (p < 0.01).

CONCLUSION

SDD used as an adjunct to SRP provides significant benefit for elderly patients with CP compared with SRP alone.

Association between periodontal disease and left ventricle mass in essential hypertension

Chronic periodontitis has been associated with an increased risk for cardiovascular disease. Left ventricular mass is an established independent predictor of cardiovascular disease. In the present cross-sectional study, we tested the association between periodontitis and left ventricular mass in subjects with essential hypertension. One hundred four untreated subjects with essential hypertension underwent clinical examinations, including echocardiographic study, laboratory tests, and assessment of periodontal status according to the community periodontal index of treatment needs (CPITN). With increasing severity of periodontitis, there was a progressive increase in left ventricle mass. Mean values (g/height2.7) were 39.0 (+/-2.7) in CPITN 0 (periodontal health), 40.2 (+/-6.4) in CPITN 1 (gingival bleeding), 42.7 (+/-6.8) in CPITN 2 (calculus), 51.4 (+/-11.7) in CPITN 3 (pockets 4 to 5 mm), and 76.7 (+/-11.3) in CPITN 4 (pockets > or =6 mm) (overall F 51.2; P<0.0001). Body surface area (P=0.04), systolic (P<0.0001) and diastolic (P<0.01) blood pressure, and left ventricular mass (P<0.0001) were determinants of a composite of CPITN 3 and 4. In a multivariate logistic analysis, left ventricular mass was the sole determinant (P<0.0001) of CPITN stages 3 and 4. Our findings suggest a direct association between severity of periodontitis and left ventricular mass in subjects with essential hypertension. Periodontal evaluation might contribute to refine cardiovascular risk assessment in hypertensive subjects.

Periodontal treatment practices of Finnish dentists

OBJECTIVES

To evaluate the treatment practices of Finnish general practitioners (GPs) and dental teachers (DTs) regarding periodontal treatment modalities, and their knowledge of possible contraindications for periodontal surgery.

MATERIAL AND METHODS

A questionnaire on two periodontal cases was mailed to 400 GPs, selected by stratified randomization from the public and private sector, and to 47 DTs. The response rate was 77%. Respondents were asked to choose the optimal treatment for a patient with a bleeding, 8-mm-deep periodontal pocket and to consider the influence on their treatment decision of the six possible contraindications for periodontal surgery presented, two of which were absolute (inadequate oral hygiene and poorly controlled diabetes) and four of which were relative contraindications. The respondents' treatment decisions were compared with recommendations from textbooks and the Consensus Report from the 1996 World Workshop of Periodontology.

RESULTS

The majority of public (65%) and private (70%) dentists and almost all of the DTs chose treatment in agreement with recommendations. Correct answers from dentists were associated with a greater number of days in continuing education (OR = 1.5; p= 0.005). The two absolute contraindications were known by 38% of public and 31% of private sector dentists, and by 29% of DTs. The respective figures for relative contraindications were 40, 58 and 53%.

CONCLUSION

The majority of Finnish dentists followed the recommendations, but elaboration of international guidelines for good clinical practice is still needed to help clinicians to make optimal treatment decisions.

Antibody-based diagnostic for 'refractory' periodontitis

OBJECTIVE

About 10-15% of US adults are 'refractory' to therapy for chronic periodontitis. Recently, studies suggest that these patients have elevated lysine decarboxylase activity in the sulcular microbiota. The aim of this study was to determine whether an elevated IgG antibody response to lysine decarboxylase, alone or with antibody to other bacterial antigens and baseline clinical measurements, would predict 'refractory' patients with high accuracy.

METHODS

Chronic periodontitis patients were treated using scaling and root planing (SRP) followed by maintenance SRP and 3-monthly re-examinations. If there was a loss of mean full mouth attachment or more than three sites appeared with > 2.5 mm new loss within a year, the subjects were re-treated (modified Widman flap surgery and systemically administered tetracycline). If attachment loss as above recurred, the subjects were 'refractory'. Baseline clinical measurements and specific antibody responses were used in a logistic regression model to predict 'refractory' subjects.

RESULTS

Antibody to a peptide portion of lysine decarboxylase (HKL-Ab) and baseline bleeding on probing (BOP) prevalence measurements predicted attachment loss 3 months after initial therapy [pIAL = loss (0) or gain (1)]. IgG antibody contents to a purified antigen from Actinomyces spp. (A-Ab) and streptococcal d-alanyl glycerol lipoteichoic acid (S-Ab) were related in 'refractory' patients (R2 = 0.37, p < 0.01). From the regression equation, the relationship between the antibodies was defined as linear (pLA/S-Ab = 0) or non-linear pLA/S-Ab = 1). Using pLA/S-Ab, pIAL and age, a logistic regression equation was derived from 48 of the patients. Of 59 subjects, 37 had 2-4 mm attachment loss and were assigned as 'refractory' or successfully treated with 86% accuracy.

CONCLUSION

HKL-Ab facilitated an accurate prediction of therapeutic outcome in subjects with moderate periodontitis.

The oral cleanliness and periodontal health of UK adults in 1998

Periodontal disease continues to be a major concern for dentists and patients. This paper reports the findings of the 1998 UK Adult Dental Health survey in relation to plaque, calculus, periodontal pocketing and loss of attachment. It is apparent from this study that moderate periodontal disease remains commonplace amongst UK adults and that the associated risk factors of plaque and calculus are in abundance, even amongst those who profess to be motivated about their oral health and attend the dentist regularly. The continued high prevalence of disease needs to be seen in the context of the far larger number of people who are now potentially at some risk, particularly in the older age groups, because of improvements in tooth retention. However, the cumulative effect of disease means that control of the periodontal diseases, even mild and slowly progressing disease, will be a key issue if large numbers of teeth are to be retained into old age. If that level of control is to be achieved we need a widespread improvement in our management of the disease, particularly in our ability to improve the oral cleanliness of the UK population.

Practical periodontal screening and diagnosis

The differences in approach between screening for and diagnosis of periodontal diseases are highlighted. The Periodontal Screening and Recording procedure is discussed in terms of its evolution and current application. For patients screened and found to have more advanced periodontal problems a panoramic dental radiograph with restricted supplemented periapicals are recommended. A comprehensive clinical periodontal examination should be performed for these patients, but it is argued that this may be performed after the initial hygiene phase of treatment. In establishing a diagnosis it is suggested that attention be paid to possible risk exposures. Newer, non-anatomic diagnostic procedures are discussed in principle and it is concluded that these do not have a practical application at present.

Children, adolescents and periodontal diseases

OBJECTIVES

This manuscript attempts to critically review current literature regarding the natural history, aetiology and pathogenesis of the common periodontal diseases to affect children and adolescents. The logic behind the emergence of a new classification in the early 1990s is explained and potential problems with the interpretation of such systems outlined.

DATA SOURCES

The manuscript focuses upon recent developments, reported in the international periodontal literature, aimed at unraveling the molecular basis for this group of diseases. The concept of one disease type progressing with time to another disease within the same individual is discussed, and early data presented that indicate the possibility of microbial transmission from deciduous to permanent dentition's within a subject.

CONCLUSIONS

It is concluded that differing classification systems for adolescent and childhood periodontal diseases may lead to confusion within the dental profession, unless the clinical and molecular basis for such diseases is fully understood. Further advances in basic research using molecular biology tools should assist in our understanding of the aetiopathology at a molecular level and hopefully lead to the development of new treatment strategies.