Gingival crevicular fluid collagenase-2 (MMP-8) test stick for chair-side monitoring of periodontitis

Theaflavin -3,3'-digallate/ethanol: a novel cross-linker for stabilizing dentin collagen

Objectives

To study the ability of theaflavin-3,3'-digallate (TF3)/ethanol solution to crosslink demineralized dentin collagen, resist collagenase digestion, and explore the potential mechanism.

Methods

Fully demineralized dentin blocks were prepared using human third molars that were caries-free. Then, these blocks were randomly allocated into 14 separate groups (n = 6), namely, control, ethanol, 5% glutaraldehyde (GA), 12.5, 25, 50, and 100 mg/ml TF3/ethanol solution groups. Each group was further divided into two subgroups based on crosslinking time: 30 and 60 s. The efficacy and mechanism of TF3's interaction with dentin type I collagen were predicted through molecular docking. The cross-linking, anti-enzymatic degradation, and biomechanical properties were studied by weight loss, hydroxyproline release, scanning/transmission electron microscopy (SEM/TEM), in situ zymography, surface hardness, thermogravimetric analysis, and swelling ratio. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were utilized to explore its mechanisms. Statistical analysis was performed using one and two-way analysis of variance and Tukey's test.

Results

TF3/ethanol solution could effectively crosslink demineralized dentin collagen and improve its resistance to collagenase digestion and biomechanical properties (p < 0.05), showing concentration and time dependence. The effect of 25 and 50 mg/ml TF3/ethanol solution was similar to that of 5% GA, whereas the 100 mg/mL TF3/ethanol solution exhibited better performance (p < 0.05). TF3 and dentin type I collagen are mainly cross-linked by hydrogen bonds, and there may be covalent and hydrophobic interactions.

Conclusion

TF3 has the capability to efficiently cross-link demineralized dentin collagen, enhancing its resistance to collagenase enzymatic hydrolysis and biomechanical properties within clinically acceptable timeframes (30 s/60 s). Additionally, it exhibits promise in enhancing the longevity of dentin adhesion.

Matrix Metalloproteinases in the Periodontium-Vital in Tissue Turnover and Unfortunate in Periodontitis

The extracellular matrix (ECM) is a complex non-cellular three-dimensional macromolecular network present within all tissues and organs, forming the foundation on which cells sit, and composed of proteins (such as collagen), glycosaminoglycans, proteoglycans, minerals, and water. The ECM provides a fundamental framework for the cellular constituents of tissue and biochemical support to surrounding cells. The ECM is a highly dynamic structure that is constantly being remodeled. Matrix metalloproteinases (MMPs) are among the most important proteolytic enzymes of the ECM and are capable of degrading all ECM molecules. MMPs play a relevant role in physiological as well as pathological processes; MMPs participate in embryogenesis, morphogenesis, wound healing, and tissue remodeling, and therefore, their impaired activity may result in several problems. MMP activity is also associated with chronic inflammation, tissue breakdown, fibrosis, and cancer invasion and metastasis. The periodontium is a unique anatomical site, composed of a variety of connective tissues, created by the ECM. During periodontitis, a chronic inflammation affecting the periodontium, increased presence and activity of MMPs is observed, resulting in irreversible losses of periodontal tissues. MMP expression and activity may be controlled in various ways, one of which is the inhibition of their activity by an endogenous group of tissue inhibitors of metalloproteinases (TIMPs), as well as reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

LIGHT protein: A novel gingival crevicular fluid biomarker associated with increased probing depth after periodontal surgery

AIM

To evaluate the protein profiles in gingival crevicular fluid (GCF) in relation to clinical outcomes after periodontal surgery and examine if any selected proteins affect the mRNA expression of pro-inflammatory cytokines in human gingival fibroblasts.

MATERIALS AND METHODS

This exploratory study included 21 consecutive patients with periodontitis. GCF was collected, and the protein pattern (n = 92) and clinical parameters were evaluated prior to surgery and 3, 6 and 12 months after surgery. Fibroblastic gene expression was analysed by real-time quantitative polymerase chain reaction.

RESULTS

Surgical treatment reduced periodontal pocket depth (PPD) and changed the GCF protein pattern. Twelve months after surgery, 17% of the pockets showed an increase in PPD. Levels of a number of proteins in the GCF decreased after surgical treatment but increased with early signs of tissue destruction, with LIGHT being one of the proteins that showed the strongest association. Furthermore, LIGHT up-regulated the mRNA expression of pro-inflammatory cytokines interleukin (IL)-6, IL-8 and MMP9 in human gingival fibroblasts.

CONCLUSIONS

LIGHT can potentially detect subjects at high risk of periodontitis recurrence after surgical treatment. Moreover, LIGHT induces the expression of inflammatory cytokines and tissue-degrading enzymes in gingival fibroblasts.

Applicability of an active matrix metalloproteinase-8 point-of-care test in an oral and maxillofacial surgery clinic: a pilot study

OBJECTIVES

Matrix metalloproteinases are enzymes that participate in numerous inflammatory responses and have been targeted as biomarkers in numerous pathologic states. The detection of active matrix metalloproteinase-8 (aMMP-8) using a mouthrinse point-of-care test (POCT) has emerged as a diagnostic marker for periodontitis and other systemic inflammatory states. The objective of this pilot study was to assess the applicability of aMMP-8 POCT in an oral and maxillofacial surgery clinic and to evaluate the relationship between aMMP-8 levels and different patient groups.

MATERIALS AND METHODS

aMMP-8 POCT samples were collected from patients in an oral and maxillofacial surgery clinic during a one-month period. aMMP-8 levels were analyzed using a chairside lateral-flow immunotest and a digital reader. Clinically relevant patient variables were collected and descriptively evaluated. aMMP-8 levels over 20 ng/ml were considered to be elevated.

RESULTS

A total of 115 patients were interviewed of which 112 agreed to the test (97.4%). Elevated aMMP-8 levels were observed in 58 (51.8%) patients. Bone loss was noted in 75 (67.0%) patients. Of these patients, aMMP-8 levels were elevated in 47 (62.7%) patients. Patients at an increased risk of infection had 35.5% higher aMMP-8 values on average compared to patients with no prior illnesses.

CONCLUSION

aMMP-8 POCT provides a non-invasive and reliable method for measuring aMMP-8 levels. Future studies are warranted to assess the clinical relevance between elevated aMMP-8 levels and specific patient groups.

CLINICAL RELEVANCE

The rapid availability of the test score allows an immediate impact on treatment planning.

Correlations between different protein species of oral rinse MMP-8 and patient-related factors

OBJECTIVES

The aim of this study is to examine correlations between different oral rinse matrix metalloproteinase (MMP)-8 protein species in western blot (WB) analysis, quantitative MMP-8 measurements, and patient-related factors. Elevated activated MMP-8 (aMMP-8) associate with periodontitis and a diagnostic point-of-care technology has been developed based on aMMP-8. In WB, different MMP-8 protein species can be analyzed. Relative abundancy of fragmented 20-25 kDa forms in WB has been associated with and reflects MMP-8 activation and related fragmentation and elevated quantitative aMMP-8 measurements.

MATERIAL AND METHODS

A random sample of 192 participants from a periodontal disease screening study was used for this study. Oral rinse samples for biomarker analyses were collected before clinical periodontal examinations. aMMP-8 immunofluorometric (IFMA) and WB analysis (utilizing the same monoclonal antibody, 8708), polymorphonuclear leukocyte (PMN) elastase activity test and tissue inhibitor of metalloproteinases (TIMP)-1 ELISA levels were performed from the oral rinse samples. Distinct MMP-8 protein species were differentiated in the WB analysis. Principal component (PC) analysis was conducted to explore correlation patterns between the different species. Adjusted correlation analysis between the extracted PCs of WB and aMMP-8 IFMA levels and multilevel regression analysis were conducted to explore if the other periodontal disease-related biomarkers and clinical surrogate measures and patient-related factors are co-variating with the extracted components.

RESULTS

Distinct correlation patterns between the MMP-8 protein species were observed. The first four PCs explained 89% of the whole variance in PC analysis. Statistically significant correlation (p < 0.05) were observed as follows: PC1 positively with 21 kDa (r = .69) and 25 kDa fragments (r = .55) and negatively with 150 kDa complexes (r = -.46). PC2 correlated with 45 (r = .70) and 55 kDa (r = .65) activated forms, PC3 with 70-80 kDa latent proforms (r = .63) and 90-100 kDa complexes (r = .67), and PC4 with 35 kDa fragments (r = .81). There were significant correlations between quantitative (IFMA) aMMP-8 measurements and PC1 (p < 0.001), PC2 (<0.05) and PC3 (<0.05) but not with PC4. In multilevel regression models age, PMN elastase activity, TIMP-1 levels, and a number of 4-5 mm periodontal pockets were associated with PC1, nonsmoking with PC2, age and PMN elastase activity with PC3, and age and smoking with PC4.

CONCLUSIONS

Relative abundancy of fragmented 21-25 kDa protein species was correlated with the quantitative aMMP-8 (IFMA) measurements, which is in line with previous results. Different patient-related factors (smoking, age, proteolytic activity) may modify the formation of different MMP-8 protein species in oral rinse samples and may cause variability in quantitative aMMP-8 measurement.

Dual-functional etchants that simultaneously demineralize and stabilize dentin render collagen resistant to degradation for resin bonding

OBJECTIVES

To develop dual-functional etchants that could demineralize and stabilize dentin collagen simultaneously, and to assess the effects of these etchants on collagen crosslinking, biostability and resin bonding properties under clinically relevant conditions.

METHODS

Dual-functional etchants were prepared by mixing 56% glycolic acid and 17% phosphoric acid and adding 1% of theaflavins (TF) or proanthocyanidins from grape seed extract (GSE). The etchant without crosslinker was used as control. The prepared human dentin specimens were treated with the 3 etchants for 30 s and analyzed for chemical interaction using Fourier transform infrared spectroscopy and resistance of the demineralized layer to collagenase degradation using electron microscopy (EM). Resin-dentin interfacial bonding properties were evaluated after 24 h and after 10,000 thermocycling through microtensile bond strength (μTBS), nanoleakage and matrix metalloproteinases (MMPs) activity via in situ zymography. Statistical analysis was done using ANOVA and post- hoc Tuckey's test.

RESULTS

Compared to control, TF and GSE dual-functional etchants were able to demineralize dentin, induce collagen crosslinking and protect the demineralized layer from collagenase degradation within 30 s. High resolution EM images showed better protection with TF etchant compared to GSE. There was a significant reduction in μTBS and an increase in nanoleakage and MMPs activity in control after thermocycling (p < 0.05) while these changes weren't seen in dual-functional etchants.

SIGNIFICANCE

Dual-functional etchants, especially TF containing, provide collagen protection against degradation and result in stable μTBS and less nanoleakage and MMPs activity under clinically relevant conditions.

An optical fiber-based point-of-care test for periodontal MMP-8 detection: a proof of concept

OBJECTIVES

The evaluation of salivary biomarkers has been proposed as a simple and non-invasive aid to the conventional periodontal diagnosis based on clinical-radiographic parameters. Matrix metalloproteinase-8 (MMP-8), especially in its active form, is considered one of the most reliable biomarkers of periodontitis, and point-of-care tests (POCTs) have been proposed for its clinical monitoring. In this proof-of-concept study, a novel highly sensitive POCT based on a plastic optical fiber (POF) biosensor exploiting surface plasmon resonance (SPR) to detect salivary MMP-8 is described.

METHODS

A SPR-POF biosensor was functionalized with a specific antibody to develop a surface-assembled monolayer (SAM) for the detection of total MMP-8. A white light source and a spectrometer connected to the biosensor were used to quantify MMP-8 level in both buffer and real matrix (saliva) by analysing the shift of the resonance wavelength determined by the specific antigen-antibody binding upon the SAM.

RESULTS

Dose-response curves by serial dilutions of human recombinant MMP-8 were realized, obtaining a limit of detection (LOD) of 40 pM (1.76 ng/ml) in buffer and 225 pM (9.9 ng/ml) in saliva and high selectivity compared to interferent analytes (MMP-2 and IL-6).

CONCLUSIONS

The proposed optical fiber-based POCT was able to detect and measure total MMP-8 with high selectivity and very low LOD in both buffer and saliva.

CLINICAL SIGNIFICANCE

The SPR-POF technology may be employed to create highly sensitive biosensors to monitor salivary MMP-8 levels. The possibility of specifically detecting its active, rather than total, form need to be further investigated. If confirmed and clinically validated, such a device may represent a promising tool to make an immediate, highly sensitive and reliable diagnosis of periodontitis, and to carry out a timely and targeted therapy, possibly helping to prevent the onset of local and systemic periodontitis-related complications.

A Comparative Analysis of Treatment-Related Changes in the Diagnostic Biomarker Active Metalloproteinase-8 Levels in Patients with Periodontitis

BACKGROUND

Previous studies have revealed the potential diagnostic utility of aMMP-8, an active form of MMP-8, in periodontal and peri-implant diseases. While non-invasive point-of-care (PoC) chairside aMMP-8 tests have shown promise in this regard, there is a dearth of literature on the evaluation of treatment response using these tests. The present study aimed to investigate treatment-related changes in aMMP-8 levels in individuals with Stage III/IV-Grade C periodontitis compared to a healthy control group, using a quantitative chairside PoC aMMP-8 test, and to determine its correlation with clinical parameters.

METHODS

The study included 27 adult patients (13 smoker, 14 non-smoker) with stage III/IV-grade C periodontitis and 25 healthy adult subjects. Clinical periodontal measurements, real-time PoC aMMP-8, IFMA aMMP-8, and Western immunoblot analyses were performed before and 1 month after anti-infective scaling and root planing periodontal treatment. Time 0 measurements were taken from the healthy control group to test the consistency of the diagnostic test.

RESULTS

Both PoC aMMP-8 and IFMA aMMP-8 tests showed a statistically significant decrease in aMMP-8 levels and improvement in periodontal clinical parameters following treatment (p < 0.05). The PoC aMMP-8 test had high diagnostic sensitivity (85.2%) and specificity (100.0%) for periodontitis and was not affected by smoking (p > 0.05). Treatment also reduced MMP-8 immunoreactivity and activation as demonstrated by Western immunoblot analysis.

CONCLUSION

The PoC aMMP-8 test shows promise as a useful tool for the real-time diagnosis and monitoring of periodontal therapy.

Breaking the Gingival Barrier in Periodontitis

The break of the epithelial barrier of gingiva has been a subject of minor interest, albeit playing a key role in periodontal pathology, transitory bacteraemia, and subsequent systemic low-grade inflammation (LGI). The significance of mechanically induced bacterial translocation in gingiva (e.g., via mastication and teeth brushing) has been disregarded despite the accumulated knowledge of mechanical force effects on tight junctions (TJs) and subsequent pathology in other epithelial tissues. Transitory bacteraemia is observed as a rule in gingival inflammation, but is rarely observed in clinically healthy gingiva. This implies that TJs of inflamed gingiva deteriorate, e.g., via a surplus of lipopolysaccharide (LPS), bacterial proteases, toxins, Oncostatin M (OSM), and neutrophil proteases. The inflammation-deteriorated gingival TJs rupture when exposed to physiological mechanical forces. This rupture is characterised by bacteraemia during and briefly after mastication and teeth brushing, i.e., it appears to be a dynamic process of short duration, endowed with quick repair mechanisms. In this review, we consider the bacterial, immune, and mechanical factors responsible for the increased permeability and break of the epithelial barrier of inflamed gingiva and the subsequent translocation of both viable bacteria and bacterial LPS during physiological mechanical forces, such as mastication and teeth brushing.

Ceramide Phosphoethanolamine as a Possible Marker of Periodontal Disease

Periodontal disease is a chronic oral inflammatory disorder initiated by pathobiontic bacteria found in dental plaques—complex biofilms on the tooth surface. The disease begins as an acute local inflammation of the gingival tissue (gingivitis) and can progress to periodontitis, which eventually leads to the formation of periodontal pockets and ultimately results in tooth loss. The main problem in periodontology is that the diagnosis is based on the assessment of the already obvious tissue damage. Therefore, it is necessary to improve the current diagnostics used to assess periodontal disease. Using lipidomic analyses, we show that both crucial periodontal pathogens, Porphyromonas gingivalis and Tannerella forsythia, synthesize ceramide phosphoethanolamine (CPE) species, membrane sphingolipids not typically found in vertebrates. Previously, it was shown that this particular lipid can be specifically detected by an aegerolysin protein, erylysin A (EryA). Here, we show that EryA can specifically bind to CPE species from the total lipid extract from P. gingivalis. Furthermore, using a fluorescently labelled EryA-mCherry, we were able to detect CPE species in clinical samples of dental plaque from periodontal patients. These results demonstrate the potential of specific periodontal pathogen-derived lipids as biomarkers for periodontal disease and other chronic inflammatory diseases.

Human Umbilical Cord Mesenchymal Stem Cells: Current Literature and Role in Periodontal Regeneration

Periodontal disease can cause irreversible damage to tooth-supporting tissues such as the root cementum, periodontal ligament, and alveolar bone, eventually leading to tooth loss. While standard periodontal treatments are usually helpful in reducing disease progression, they cannot repair or replace lost periodontal tissue. Periodontal regeneration has been demonstrated to be beneficial in treating intraosseous and furcation defects to varied degrees. Cell-based treatment for periodontal regeneration will become more efficient and predictable as tissue engineering and progenitor cell biology advance, surpassing the limitations of present therapeutic techniques. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into several cell types when stimulated. Mesenchymal stem cells (MSCs) have been tested for periodontal regeneration in vitro and in humans, with promising results. Human umbilical cord mesenchymal stem cells (UC-MSCs) possess a great regenerative and therapeutic potential. Their added benefits comprise ease of collection, endless source of stem cells, less immunorejection, and affordability. Further, their collection does not include the concerns associated with human embryonic stem cells. The purpose of this review is to address the most recent findings about periodontal regenerative mechanisms, different stem cells accessible for periodontal regeneration, and UC-MSCs and their involvement in periodontal regeneration.

TNF-α, IL-1β, MMP-8 Crevicular Profile in Patients with Chronic Kidney Disease and Periodontitis

Increasing evidence sustains the potential of periodontitis as a risk factor for chronic kidney disease (CKD). Our study aimed to analyze several periodontal specific inflammatory biomarkers within the gingival crevicular fluid (GCF) of patients with CKD, compared to patients with normal kidney function, providing an inflammatory profile of the dialysis patient. The study comprised 79 patients divided into: group 1 (59 subjects with periodontitis and CKD) and group 2 (20 patients with periodontitis, without other systemic conditions). Clinical diagnosis was performed via dental and periodontal examination. GCF samples were collected from each patient, and the levels of TNF-α, IL-1β and MMP-8 were determined by using ELISA assay. In group 1, the average values were: 22.85 ± 5.87 pg/mL for TNF-α, 33.00 ± 39.68 pg/mL for IL-1β and 18.80 ± 27.75 ng/mL for MMP-8. In group 2, the mean values were: 2.10 ± 1.34 pg/mL for TNF-α, 0.71 ± 2.42 pg/mL for IL-1β and 5.35 ± 0.37 ng/mL for MMP-8. Statistical analysis revealed significant differences between groups as referring to all three biomarkers and, TNF-α and MMP-8, in certain stages of periodontitis. The level of TNF-α, IL-1β and MMP-8 points out the increased inflammatory status of the dialysis patient with PD, supporting the mutual connection of the two pathologies.

Neutrophils Orchestrate the Periodontal Pocket

The subgingival biofilm attached to tooth surfaces triggers and maintains periodontitis. Previously, late-onset periodontitis has been considered a consequence of dysbiosis and a resultant polymicrobial disruption of host homeostasis. However, a multitude of studies did not show "healthy" oral microbiota pattern, but a high diversity depending on culture, diets, regional differences, age, social state etc. These findings relativise the aetiological role of the dysbiosis in periodontitis. Furthermore, many late-onset periodontitis traits cannot be explained by dysbiosis; e.g. age-relatedness, attenuation by anti-ageing therapy, neutrophil hyper-responsiveness, and microbiota shifting by dysregulated immunity, yet point to the crucial role of dysregulated immunity and neutrophils in particular. Furthermore, patients with neutropenia and neutrophil defects inevitably develop early-onset periodontitis. Intra-gingivally injecting lipopolysaccharide (LPS) alone causes an exaggerated neutrophil response sufficient to precipitate experimental periodontitis. Vice versa to the surplus of LPS, the increased neutrophil responsiveness characteristic for late-onset periodontitis can effectuate gingiva damage likewise. The exaggerated neutrophil extracellular trap (NET) response in late-onset periodontitis is blameable for damage of gingival barrier, its penetration by bacteria and pathogen-associated molecular patterns (PAMPs) as well as stimulation of Th17 cells, resulting in further neutrophil activation. This identifies the dysregulated immunity as the main contributor to periodontal disease.

Theaflavins as a novel cross-linker quickly stabilize demineralized dentin collagen against degradation

To investigate the ability of theaflavins (TF) from black tea to protect dentin collagen against enzymatic degradation via cross-linking effect under clinically relevant conditions. 10-µm-thick dentin films were microtomed from dentin slabs of human molars. Following demineralization, films or slabs were treated with TF at two concentrations (0.4% and 2%) for 30 s. A well-known collagen cross-linker grape seed proanthocyanidins (PA) was used as control. Collagen cross-linking interactions and stabilization against enzymatic degradation were investigated by Fourier transform infrared spectroscopy, weight loss, hydroxyproline release, and scanning/transmission electron microscopy. Data were analyzed by ANOVA, Tukey’s and Student’s T test (α = 0.05%). The results showed collagen cross-linking and stabilization efficacy was dependent on TF/PA concentrations. At 2.0%, TF and PA offered nearly full protection to collagen; at 0.4%, TF exhibited a significantly better collagen stabilization effect than PA (P < 0.05), while untreated collagen was completely digested. It’s concluded that TF cross-links dentin collagen within a clinically relevant time (30 s) and offers excellent collagen protection against enzymatic degradation, with efficacy comparable to or better than PA. The study supports the potential use of TF as a novel, promising collagen cross-linker for degradation resistant, long-lasting dentin bonding in composite restorations.

Evaluation of Gene Polymorphism and Gingival Crevicular Fluid Levels of Matrix Metalloproteinase-3 in a Group of Turkish Periodontitis Patients

INTRODUCTION

Periodontitis is characterized by the destruction of tooth-supporting tissues. Matrix metalloproteinases (MMPs) play a significant part in the degradation of collagen structure. The gingival crevicular fluid (GCF) levels of MMPs increase with the progression of periodontal inflammation. Polymorphisms can be responsible for high expression of MMPs and can exacerbate the breakdown of collagen structure. This study aims to investigate the effect of MMP-3 -1171 5A/6A polymorphism and the GCF levels of MMP-3 in a group of Turkish periodontitis patients.

MATERIALS AND METHODS

Non-smoking, stage II grade A periodontitis (S II-Gr A) (n = 68) and stage II grade B periodontitis (S II-Gr C) (n = 64) patients were recruited. Healthy individuals (H) (n = 72) without signs of gingivitis or periodontitis served as the control. Venous blood was collected from participants to obtain DNA, and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to detect polymorphism. GCF samples were taken to assess MMP-3 levels using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The MMP-3 -1179 5A/6A distribution showed no significant difference between the groups (p > 0.05). However, the MMP-3 GCF levels of the S II-Gr C group were higher than those of both the S II-Gr A and H groups (p < 0.05), and elevated MMP-3 levels were detected in S II-Gr A compared to H (p < 0.05).

CONCLUSION

The MMP-3 GCF levels showed an association with periodontal tissue destruction, although single nucleotide polymorphism was not associated with the S II-Gr C and S II-Gr A groups in the Turkish population.

Active matrix metalloproteinase-8 (aMMP-8) point-of-care test (POCT) in the COVID-19 pandemic

INTRODUCTION

Active matrix metalloproteinase (aMMP)-8 utilized in point-of-care testing (POCT) is regarded as a potential biomarker for periodontal and peri-implant diseases. Various host and microbial factors eventually influence the expression, degranulation, levels and activation of aMMP-8. The type of oral fluids (saliva, mouthrinse, gingival crevicular, and peri-implant sulcular fluids [GCF/PISF], respectively) affect the analysis.

AREAS COVERED

With this background, we aimed to review here the recent studies on practical, inexpensive, noninvasive and quantitative mouthrinse and GCF/PISF chair-side POCT lateral flow aMMP-8 immunoassays (PerioSafe and ImplantSafe/ORALyzer) and how they help to detect, predict, monitor the course, treatment and prevention of periodontitis and peri-implantitis. The correlations of aMMP-8 POCT to other independent and catalytic activity assays of MMP-8 are also addressed.

EXPERT OPINION

The mouthrinse aMMP-8 POCT can also detect prediabetes/diabetes and tissue destructive oral side-effects due to the head and neck cancers' radiotherapy. Chlorhexidine and doxycycline can inhibit collagenolytic human neutrophil and GCF aMMP-8. Furthermore, by a set of case-series we demonstrate the potential of mouthrinse aMMP-8 POCT to real-time/online detect periodontitis as a potential risk disease for coronavirus disease 2019 (COVID-19). The clinical interdisciplinary utilization of aMMP-8 POCT requires additional oral, medical, and interdisciplinary studies.

Active MMP-8 Quantitative Test as an Adjunctive Tool for Early Diagnosis of Periodontitis

Periodontitis is a host-mediated bacterial disease that affects the tooth attachment apparatus. Metalloproteinase-8 (MMP-8), a validated biomarker, could aid in clinical diagnosis. This study aimed to evaluate the diagnostic performance of active (a) MMP-8 immunotest versus total (t) MMP-8 ELISA for quantitative real-time diagnosis and assessment of periodontitis severity at the site level. Gingival crevicular fluid (GCF) was sampled from 30 healthy, 42 mild, and 59 severe periodontitis sites from thirty-one volunteers. MMP-8 concentrations were determined by time-resolved immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using the STATA package. Both active and total MMP-8-based methods discriminated among sites according to periodontal diagnosis and severity, with a positive correlation between the two tests (p < 0.001). (a) MMP-8 models showed the best performance in receiver operating characteristic (ROC) curves to discriminate between healthy and periodontitis sites (area under the curve [AUC] = 0.89), while (t) MMP-8 demonstrated a high diagnostic precision in the detection of mild from severe periodontitis sites (AUC ≥ 0.80). The use of (a) MMP-8 and (t) MMP-8 could represent a useful adjunctive tool for periodontitis diagnosis and severity. These results support the applicability of new point-of-care methods in the monitoring of high-risk periodontal patients.

Comparing periodontitis biomarkers in saliva, oral rinse and gingival crevicular fluid: A pilot study

AIM

To explore the feasibility of screening for periodontitis by measuring biomarkers, namely total proteolytic activity (TPA), matrix metalloproteinase (MMP)-8, chitinase, lysozyme or their combination, in saliva, oral rinse and gingival crevicular fluid (GCF).

MATERIAL AND METHODS

Subjects were recruited among healthy/gingivitis individuals and untreated periodontitis patients in Academic Centre for Dentistry Amsterdam (ACTA). All participants donated samples of unstimulated whole saliva, oral rinse and GCF. The protein concentrations and MMP-8 levels were determined by ELISA. Enzymatic activities were measured using appropriate fluorogenic substrates.

RESULTS

In oral rinse samples, periodontitis patients (n = 19) exhibited significantly higher concentrations of MMP-8 and TPA than controls (n = 20). MMP-8 in combination with chitinase explained 88% of the variance and assigned a subject to control or periodontitis group, with best accuracy (87.2%) in oral rinse.

CONCLUSIONS

The combination of MMP-8 and chitinase in the current oral rinse procedure has the potential to discriminate periodontitis from periodontal health/gingivitis.

Indocyanine Green-Assisted and LED-Light-Activated Antibacterial Photodynamic Therapy Reduces Dental Plaque

Aim: This study aimed to determine the feasibility and first efficacy of indocyanine green (ICG)-assisted antimicrobial photodynamictherapy (aPDT) as activated using LED light to the dental plaque. Methods: Fifteen healthy adults were assigned to this four-day randomized study. After rinsing with ICG, 100 J/cm² of 810 nm LED light was applied to the aPDT-treatment area. Plaque area and gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) were measured, and plaque bacteriomes before and after the study were analyzed using 16S rRNA sequencing. Results: aPDT administration was preformed successfully and plaque-specifically with the combination of ICG and the applicator. Total plaque area and endpoint MMP-8 levels were reduced on the aPDT-treatment side. aPDT reduced Streptococcus, Acinetobacteria, Capnocytophaga, and Rothia bacteria species in plaques. Conclusion: ICG-assisted aPDT reduces plaque forming bacteria and exerts anti-inflammatory and anti-proteolytic effects.

Connection between Periodontitis-Induced Low-Grade Endotoxemia and Systemic Diseases: Neutrophils as Protagonists and Targets

Periodontitis is considered a promoter of many systemic diseases, but the signaling pathways of this interconnection remain elusive. Recently, it became evident that certain microbial challenges promote a heightened response of myeloid cell populations to subsequent infections either with the same or other pathogens. This phenomenon involves changes in the cell epigenetic and transcription, and is referred to as ''trained immunity''. It acts via modulation of hematopoietic stem and progenitor cells (HSPCs). A main modulation driver is the sustained, persistent low-level transmission of lipopolysaccharide from the periodontal pocket into the peripheral blood. Subsequently, the neutrophil phenotype changes and neutrophils become hyper-responsive and prone to boosted formation of neutrophil extracellular traps (NET). Cytotoxic neutrophil proteases and histones are responsible for ulcer formations on the pocket epithelium, which foster bacteremia and endoxemia. The latter promote systemic low-grade inflammation (SLGI), a precondition for many systemic diseases and some of them, e.g., atherosclerosis, diabetes etc., can be triggered by SLGI alone. Either reverting the polarized neutrophils back to the homeostatic state or attenuation of neutrophil hyper-responsiveness in periodontitis might be an approach to diminish or even to prevent systemic diseases.

Dual-Functionality Evaluation of a Novel Collagen Crosslinking Resin

Current adhesives bond to dentin via a micro-interlocking mechanism within the hybrid layer. Besides such mechanical retention, bonding to dentin would benefit from additional chemical interaction between collagen and resin. This study aims to synthesize a novel light-curable collagen crosslinker methacrylate (MA) functionalized grapeseed extract (GSE) and to assess MAGSE's ability to crosslink dentin collagen in a clinically relevant setting as well as its role in light-cure as a resin. MA functionalization was accomplished by reacting GSE with methacryloyl chloride to obtain MAGSE, which was characterized by ¹H-NMR and Fourier transformed infrared spectroscopy (FTIR). The 6-µm-thick dentin films were microtomed from dentin slabs of third molars. Following demineralization, they were treated for 30 s by 1% MAGSE. Collagen crosslinking and resistance to digestion of MAGSE were evaluated by FTIR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) assay of films, and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) on slabs. Meanwhile, 1% MAGSE or GSE was added to an experimental adhesive formulated with 2-hydroxyethyl methacrylate and a tricomponent photoinitiator system. Polymerization kinetics were monitored continuously in real time for 10 min using FTIR-attenuated total reflection. The results indicated that MAGSE could bind to dentin collagen and protect it from collagenase degradation as strong as GSE. Dentin collagen treated by 1% MAGSE for 30 s was scarcely digested (1.6 ± 1.6%) after 1 h in 0.1% collagenase, while untreated collagen was completely digested (100.9 ± 20.2%). SEM/TEM images indicated MAGSE efficiently crosslinked dentin collagen in 30 s and rendered it almost inert to digestion under clinically relevant settings. Unlike GSE that hindered light-curing of HEMA, MAGSE accelerated the rate of polymerization and exhibited typical traits of a resin monomer with multiple polymerizable units. In conclusion, a novel collagen crosslinking resin MAGSE is synthesized, which inherits collagen crosslinking ability from GSE and polymerization function from MA. Inclusion of this light-curable collagen crosslinker into adhesives might be a revolutionary way to improve durability of dentin bonding in composite restorations.

Salivary Biomarkers and Oral Health in Liver Transplant Recipients, with an Emphasis on Diabetes

Salivary biomarkers have been linked to various systemic diseases. We examined the association between salivary biomarkers, periodontal health, and microbial burden in liver transplant (LT) recipients with and without diabetes, after transplantation. We hypothesized that diabetic recipients would exhibit impaired parameters. This study included 84 adults who received an LT between 2000 and 2006 in Finland. Dental treatment preceded transplantation. The recipients were re-examined, on average, six years later. We evaluated a battery of salivary biomarkers, microbiota, and subjective oral symptoms. Periodontal health was assessed, and immunosuppressive treatments were recorded. Recipients with impaired periodontal health showed higher matrix metalloproteinase-8 (MMP-8) levels (p < 0.05) and MMP-8/tissue inhibitor of matrix metalloproteinase 1 (TIMP1) ratios (p < 0.001) than recipients with good periodontal health. Diabetes post-LT was associated with impaired periodontal health (p < 0.05). No difference between groups was found in the microbial counts. Salivary biomarker levels did not seem to be affected by diabetes. However, the advanced pro-inflammatory state induced by and associated with periodontal inflammation was reflected in the salivary biomarker levels, especially MMP-8 and the MMP-8/TIMP-1 molar ratio. Thus, these salivary biomarkers may be useful for monitoring the oral inflammatory state and the course of LT recipients.

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.

Evaluation of active matrix metalloproteinase-8 (aMMP-8) chair-side test as a diagnostic biomarker in the staging of periodontal diseases

OBJECTIVE

There is a need for a reliable complementary diagnostic tool that ideally helps to screen, differentiate sites, activities of and predict future periodontal tissue destruction. The purpose of this cross-sectional study was to investigate the screening and prevention potential of the chair-side/point-of-care (PoC) diagnostic test of salivary active matrix metalloproteinase-8 (aMMP-8) levels at different stages of periodontal disease and periodontal health.

MATERIAL & METHODS

80 individuals were included in this study; 18 with periodontitis stage 3 (P-Stage III), 19 with periodontitis stage-4 (P-Stage IV), 21 with gingivitis, and 22 with clinically healthy periodontium (H). The aMMP-8 levels in GCF and saliva were analyzed by chairside point-of-care aMMP-8 lateral flow immunotest and also by a time-resolved immunofluorescence assay (IFMA).

RESULTS

The sensitivity of the chair-side/PoC test was 83.9 % while specificity was 79.2 %. The aMMP-8 IFMA levels in GCF were significantly higher in P-Stage IV group than P-Stage III, gingivitis and healthy groups (p = 0.01, p = 0.001, p = 0.00, respectively). Moreover, P-Stage III and gingivitis groups had significantly higher aMMP-8 IFMA levels than the healthy group (p < 0.05).

CONCLUSION

The aMMP-8 chair-side test showed promising results in its ability to recognize and predict the inflammatory status even at the very initial/early stages. aMMP-8 chair-side test could be a valuable adjunctive diagnostic and preventive tool to conventional clinical methods in detecting periodontal disease.

Extracellular matrix degradation by host matrix metalloproteinases in restorative dentistry and endodontics: An overview

Matrix metalloproteinases (MMPs) are a group of over 25 secreted and membrane-bound enzymes responsible for pericellular substrate degeneration. In response to injury, they play key roles in morphogenesis, wound healing, tissue repair and remodeling. They have been isolated from dentin, odontoblasts, pulp and periapical tissue. They play a major role in the formation of dentin matrix and secondary and tertiary dentin. These are also responsible for releasing dentinal growth factors. MMP family proteins elicit a dual role in the pathogenesis of inflammation, stimulating protective innate and/or adaptive immune functions, as well as tissue destruction. The main organic component of tooth structure is collagen, and MMPs that degrade collagen and the extracellular matrix have been implicated in the progression of dental caries, dental erosion as well as degradation of the hybrid layer. MMPs have also been shown to be active in pulpitis, and studies have shown that they can be used as diagnostic markers of pulpal and periapical inflammation. This review describes the role of MMPs in dental caries, dental erosion, bond stability as well as in pulpal and periapical inflammation.

NETs Are Double-Edged Swords with the Potential to Aggravate or Resolve Periodontal Inflammation

Periodontitis is a general term for diseases characterised by inflammatory destruction of tooth-supporting tissues, gradual destruction of the marginal periodontal ligament and resorption of alveolar bone. Early-onset periodontitis is due to disturbed neutrophil extracellular trap (NET) formation and clearance. Indeed, mutations that inactivate the cysteine proteases cathepsin C result in the massive periodontal damage seen in patients with deficient NET formation. In contrast, exaggerated NET formation due to polymorphonuclear neutrophil (PMN) hyper-responsiveness drives the pathology of late-onset periodontitis by damaging and ulcerating the gingival epithelium and retarding epithelial healing. Despite the gingival regeneration, periodontitis progression ends with almost complete loss of the periodontal ligament and subsequent tooth loss. Thus, NETs help to maintain periodontal health, and their dysregulation, either insufficiency or surplus, causes heavy periodontal pathology and edentulism.

In situ gel drug delivery system for periodontitis: an insight review

Background

Periodontitis is a microbial disease that leads to inflammation in the tooth-supporting tissues of the oral cavity that is common among the elderly. It is initiated by oral inflammation induced by bacterial dysbiosis. Choosing an appropriate antimicrobial agent with the right course of drug administration is the key to successful periodontal therapy. In recent times, with more biomarkers and the development of new technologies, several point-of-care testing (POCT) platforms have been developed for the diagnosis and monitoring of periodontitis. This review focuses on oral microbiology and the pathogenesis of periodontitis as well as recent insights into the in situ gel system for periodontitis.

Design

An exhaustive search was conducted in the following scientific databases Science Direct, Springer, Pub Med, and Google Scholar to review all relevant literatures. This is a comprehensive narrative review of the literature, summarizing the perspectives of the authors.

Results

Novel in situ forming gel is introduced at the site that shows a promising potential to overcome one of the main practical obstacles associated with the treatment of local periodontitis: partial adhesion to the surrounding tissue, causing in the accidental expulsion of at least parts of the implants from patient’s pockets. This results in a large residence time of the system at the site of action and uncertainty of the final exposure to the drug.

Conclusion

From the reviewed literature, it is concluded that experimental evidence suggests that the in situ gel-forming systems can be useful in treating several common diseases of the oral cavity. Future research should focus on clinical studies to be performed for the in situ gel to make a significant contribution to periodontitis.

Graphical abstract

Diagnostic biomarker candidates for pulpitis revealed by bioinformatics analysis of merged microarray gene expression datasets

Background

Pulpitis is an inflammatory disease, the grade of which is classified according to the level of inflammation. Traditional methods of evaluating the status of dental pulp tissue in clinical practice have limitations. The rapid and accurate diagnosis of pulpitis is essential for determining the appropriate treatment. By integrating different datasets from the Gene Expression Omnibus (GEO) database, we analysed a merged expression matrix of pulpitis, aiming to identify biological pathways and diagnostic biomarkers of pulpitis.

Methods

By integrating two datasets (GSE77459 and GSE92681) in the GEO database using the sva and limma packages of R, differentially expressed genes (DEGs) of pulpitis were identified. Then, the DEGs were analysed to identify biological pathways of dental pulp inflammation with Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and Gene Set Enrichment Analysis (GSEA). Protein–protein interaction (PPI) networks and modules were constructed to identify hub genes with the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape.

Results

A total of 470 DEGs comprising 394 upregulated and 76 downregulated genes were found in pulpitis tissue. GO analysis revealed that the DEGs were enriched in biological processes related to inflammation, and the enriched pathways in the KEGG pathway analysis were cytokine-cytokine receptor interaction, chemokine signalling pathway and NF-κB signalling pathway. The GSEA results provided further functional annotations, including complement system, IL6/JAK/STAT3 signalling pathway and inflammatory response pathways. According to the degrees of nodes in the PPI network, 10 hub genes were identified, and 8 diagnostic biomarker candidates were screened: PTPRC, CD86, CCL2, IL6, TLR8, MMP9, CXCL8 and ICAM1.

Conclusions

With bioinformatics analysis of merged datasets, biomarker candidates of pulpitis were screened and the findings may be as reference to develop a new method of pulpitis diagnosis.

The Role of Matrix Metalloproteinases in Periodontal Disease

This review provides a detailed description of matrix metalloproteinases (MMPs), focusing on those that are known to have critical roles in bone and periodontal disease. Periodontal disease is an inflammatory process initiated by anaerobic bacteria, which promote the host immune response in the form of a complex network of molecular pathways involving proinflammatory mediators such as cytokines, growth factors, and MMPs. MMPs are a family of 23 endopeptidases, collectively capable of degrading virtually all extracellular matrix (ECM) components. This study critically discusses the available research concerning the involvement of the MMPs in periodontal disease development and progression and presents possible therapeutic strategies. MMPs participate in morphogenesis, physiological tissue turnover, and pathological tissue destruction. Alterations in the regulation of MMP activity are implicated in the manifestation of oral diseases, and MMPs comprise the most important pathway in tissue destruction associated with periodontal disease. MMPs can be considered a risk factor for periodontal disease, and measurements of MMP levels may be useful markers for early detection of periodontitis and as a tool to assess prognostic follow-ups. Detection and inhibition of MMPs could, therefore, be useful in periodontal disease prevention or be an essential part of periodontal disease therapy, which, considering the huge incidence of the disease, may greatly improve oral health globally.

Active MMP-8 (aMMP-8) as a Grading and Staging Biomarker in the Periodontitis Classification

The aim of this study was to investigate the utility of incorporating active matrix metalloproteinase-8 (aMMP-8) as a biomarker into the new periodontitis classification system (stage/grade) presented in 2018. This study included 150 Greek adults aged 25-78, of whom 74 were men and 76 women. Participants were tested with an aMMP-8 point-of-care mouthrinse test, after which a full-mouth clinical examination was performed to assess their periodontal and oral health. The aMMP-8 levels in mouthrinse were significantly lower among healthy patients compared with patients in more severe periodontitis stages and grades (Kruskal-Wallis test and Dunn-Bonferroni test for pairwise post-hoc comparisons; p < 0.01 and p < 0.05, respectively). Furthermore, aMMP-8 levels were less correlated with plaque levels than bleeding on probing (BOP) (Spearman's rho = 0.269, p < 0.001; Spearman's rho = 0.586, p < 0.001); respectively). Thus, aMMP-8 was more robust to the confounding effects of oral hygiene than traditional periodontal parameter bleeding on probing. The aMMP-8 point-of-care mouthrinse test can be utilized as an adjunctive and preventive diagnostic tool to identify periodontal disease, classified by stage and grade, and ongoing periodontal breakdown chairside in clinical practice in only 5 min. Overall, integrating aMMP-8 into the new periodontitis classification system seems beneficial.

Detection of peri-implant inflammation by the use of a matrix metalloproteinase-8 chair-side test

BACKGROUND

Active matrix metalloproteinase-8 (MMP-8) enzymes are associated with inflammation and the degradation of implant-supporting tissues. A high concentration of these enzymes in the peri-implant sulcular fluid (PISF) has been associated with a pathological condition. The aim of the present study was to evaluate the ability of a chair-side MMP-8 test to individuate pathological peri-implant site. The working hypothesis is that positive response to MMP-8 test corresponds to pathological values of periodontal indexes. A secondary working hypothesis is that PISF sampling method influences the test accuracy.

METHODS

Fifty implants from 50 patients were evaluated during scheduled follow-up appointments in a clinical setting using the MMP-8 chair-side test and periodontal indices (probing depth, bleeding on probing, plaque index and peri-implant inflammation index). Two methods of PISF sampling were tested.

RESULTS

The MMP-8 test demonstrated significant diagnostic capacity and good sensitivity and accuracy regarding indices of bleeding on probing, plaque index, and peri-implant inflammation index but fair agreement.

CONCLUSIONS

Further studies should be performed to better define the interpretation of the MMP-8 chair-test results and their correlation to peri-implant indexes.

Identification of Salivary Microbiota and Its Association With Host Inflammatory Mediators in Periodontitis

Periodontitis is a microbial-induced chronic inflammatory disease, which may not only result in tooth loss, but can also contribute to the development of various systemic diseases. The transition from healthy to diseased periodontium depends on microbial dysbiosis and impaired host immune response. Although periodontitis is a common disease as well as associated with various systemic inflammatory conditions, the taxonomic profiling of the salivary microbiota in periodontitis and its association with host immune and inflammatory mediators has not been reported. Therefore, the aim of this study was to identify key pathogens and their potential interaction with the host's inflammatory mediators in saliva samples for periodontitis risk assessment. The microbial 16S rRNA gene sequencing and the levels of inflammatory mediators were performed in saliva samples from patients with chronic periodontitis and periodontally healthy control subjects. The salivary microbial community composition differed significantly between patients with chronic periodontitis and healthy controls. Our analyses identified a number of microbes, including bacteria assigned to Eubacterium saphenum, Tannerella forsythia, Filifactor alocis, Streptococcus mitis/parasanguinis, Parvimonas micra, Prevotella sp., Phocaeicola sp., and Fretibacterium sp. as more abundant in periodontitis, compared to healthy controls. In samples from healthy individuals, we identified Campylobacter concisus, and Veillonella sp. as more abundant. Integrative analysis of the microbiota and inflammatory mediators/cytokines revealed associations that included positive correlations between the pathogens Treponema sp. and Selenomas sp. and the cytokines chitinase 3-like 1, sIL-6Rα, sTNF-R1, and gp130/sIL-6Rβ. In addition, a negative correlation was identified between IL-10 and Filifactor alocis. Our results reveal distinct and disease-specific patterns of salivary microbial composition between patients with periodontitis and healthy controls, as well as significant correlations between microbiota and host-mediated inflammatory cytokines. The positive correlations between the pathogens Treponema sp. and Selenomas sp. and the cytokines chitinase 3-like 1, sIL-6Rα, sTNF-R1, and gp130/sIL-6Rβ might have the future potential to serve as a combined bacteria-host salivary biomarker panel for diagnosis of the chronic infectious disease periodontitis. However, further studies are required to determine the capacity of these microbes and inflammatory mediators as a salivary biomarker panel for periodontitis.

Matrix metalloproteinases and inhibitors in dentistry

OBJECTIVES

Matrix metalloproteinase (MMP) expression has been associated with tissue development, invasive cancer cell behavior, and inflammation. The associations of increased expression of MMPs with diseases have led to intensive research activities to develop MMP inhibitors. Here, the questions are addressed which associations between increased levels of any MMP with dental diseases may be cause or consequence, whether MMP levels may be of diagnostic value and whether and which MMP inhibitors need further investigations for use in dental diseases.

METHODS

To study the role of MMPs and to discriminate between cause or consequence, the literature about measurements of MMPs and about the use of inhibitory drugs and genetic knockout animal models in dentistry was compared.

RESULTS

The only FDA-approved treatment with MMP inhibitors is tetracyclines for periodontitis, whereas a diagnostic test for activated MMP-8 in oral fluids is valued in practical periodontology. The MMP literature in dentistry is artificially skewed to the gelatinases MMP-2 and MMP-9 and to enamelysin, alias MMP-20. The basis for this observation is, respectively, the widely used and sensitive technique of gelatin zymography and enamel proteins as substrates of MMP-20. Studies on additional MMPs are gaining interest in dentistry and MMP inhibitors may provide new applications. In addition, drugs with proven effects for the treatment of dental diseases may be found to act through MMP inhibition.

CONCLUSION AND RELEVANCE

In conclusion, research on MMPs and inhibitors may provide practical applications beyond diagnosis and treatment of periodontitis and will be, directly or indirectly, beneficial for patients with dental or periodontal diseases.

Point-of-Care/Chairside aMMP-8 Analytics of Periodontal Diseases' Activity and Episodic Progression

Traditional periodontal disease diagnostics are based mainly on clinical examination and radiographs. They assess only past tissue destruction and provide no information on the current disease status or its future progression. The objective is to find out if an active matrix metalloproteinase-8 (aMMP-8) point-of-care (PoC) test could provide a cost-effective way to get around this limitation. This cross-sectional study used 47 adolescents and 70 adults, who were clinically examined and their aMMP-8 PoC tested. The aMMP-8 PoC test results and patients’ treatment need, based on the community periodontal index of treatment needs (CPITN), were compared and analyzed using Fisher’s exact test. In terms of CPITN, the aMMP-8 PoC test gave no false positives for both adolescents and adults. All healthy patients got a negative test result, while a positive test result indicated periodontal treatment need correctly. Finally, there was a significant association between a patient’s aMMP-8 PoC test result and his/her treatment need (p = 0.001 for adolescents, p = 0.001 for adults). In conclusion, more accurate diagnostics of periodontal diseases’ activity and progression using an aMMP-8 PoC test may help to reduce oral health care costs by reducing patient overtreatment, improving patient outcome, and reducing the need for complex periodontal therapy.

Matrix Metalloproteinase-8 as an Inflammatory and Prevention Biomarker in Periodontal and Peri-Implant Diseases

Levels of and especially the degree of activation of matrix metalloproteinase (MMP-8) in oral fluids (i.e., saliva, mouth rinse, gingival crevicular fluid (GCF) and peri-implantitis sulcular fluid (PISF)) increase to pathologically elevated levels in the periodontal and peri-implant diseases. This study aimed at collecting and collating data from previously published studies and determining whether active MMP-8 (aMMP-8) could serve as a biomarker for the diagnosis and prevention of periodontal and peri-implant diseases. The literature search identified a total of 284 articles. Out of 284 articles, 61 articles were found to be relevant. Data obtained from the selected studies were combined, and it indicated that aMMP-8 in oral fluids exerts the strong potential to serve as a useful adjunctive diagnostic and preventive biotechnological tool in periodontal and peri-implant diseases. aMMP-8 can be used alone or in combination with other proinflammatory and/or microbiological biomarkers.

Association of chairside salivary aMMP-8 findings with periodontal risk assessment parameters in patients receiving supportive periodontal therapy

Purpose

The aim of this retrospective cross-sectional study was to evaluate whether salivary findings of active matrix-metalloproteinase 8 (aMMP-8) chairside (point of care; POC) tests were associated with periodontal risk assessment parameters in patients receiving supportive periodontal therapy (SPT).

Methods

A total of 125 patients receiving regular SPT were included, and their records were examined. The following inclusion criteria were used: a diagnosis of chronic periodontitis, at least 1 non-surgical periodontal treatment (scaling and root planning) with following regular SPT (minimum once a year), at least 6 remaining teeth, and clinical and aMMP-8 findings that were obtained at the same appointment. In addition to anamnestic factors (e.g., smoking and diabetes), oral hygiene indices (modified sulcus bleeding index [mSBI] and approximal plaque index), periodontal probing depth simultaneously with bleeding on probing, and dental findings (number of decayed, missing, and filled teeth) were recorded. Salivary aMMP-8 levels were tested using a commercial POC test system (Periomarker, Hager & Werken, Duisburg, Germany). Statistical analysis was performed using the t-test, Mann-Whitney U test, Fisher's exact test, and χ² test, as appropriate (P<0.05).

Results

Only the mSBI was significantly associated with positive salivary aMMP-8 findings (aMMP-8 positive: 27.8%±20.9% vs. aMMP-8 negative: 18.0%±14.5%; P=0.017). No significant associations were found between aMMP-8 and smoking, diabetes, periodontal parameters, or parameters related to the maintenance interval (P>0.05).

Conclusions

Salivary aMMP-8 chairside findings were not associated with common parameters used for periodontal risk assessment in patients receiving SPT. The diagnostic benefit of POC salivary aMMP-8 testing in risk assessment and maintenance interval adjustment during SPT remains unclear.

Epigenetic Approaches to the Treatment of Dental Pulp Inflammation and Repair: Opportunities and Obstacles

Concerns over the cost and destructive nature of dental treatment have led to the call for novel minimally invasive, biologically based restorative solutions. For patients with toothache, this has resulted in a shift from invasive root-canal-treatment (RCT) toward more conservative vital-pulp-treatment (VPT) procedures, aimed to protect the pulp and harness its natural regenerative capacity. If the dental pulp is exposed, as long as the infection and inflammation can be controlled, conservative therapies can promote the formation of new tertiary dentine in a stem cell-led reparative process. Crucially, the volume and quality of new dentine is dependent on the material applied; however, currently available dental-materials are limited by non-specific action, cytotoxicity and poor clinical handling. Looking to the future, an improved understanding of the cellular regulators of pulpal inflammation and associated repair mechanisms is critical to predict pulpal responses and devise novel treatment strategies. Epigenetic modifications of DNA-associated proteins and the influences of non-coding RNAs have been demonstrated to control the self-renewal of stem cell populations as well as regulate mineralised tissue development and repair. Notably, the stability of microRNAs and their relative ease of sampling from pulpal blood highlight their potential for application as diagnostic inflammatory biomarkers, while increased understanding of their actions will not only enhance our knowledge of pulpal disease and repair, but also identify novel molecular targets. The potential therapeutic application of epigenetic modifying agents, DNA-methyltransferase-inhibitors (DNMTi) and histone-deacetylase-inhibitors (HDACi), have been shown to promote mineralisation and repair processes in dental-pulp-cell (DPC) populations as well as induce the release of bioactive dentine-matrix-components. Consequently, HDACis and DNMTis have the potential to enhance tertiary dentinogenesis by influencing the cellular and tissue processes at low concentrations with minimal side effects, providing an opportunity to develop a topically placed, inexpensive bio-inductive restorative material. The aim of this review is to highlight the potential role of epigenetic approaches in the treatment of the damaged dental pulp, considering the opportunities and obstacles, such as off-target effects, delivery mechanisms, for the therapeutic use of miRNA as an inflammatory biomarker or molecular target, before discussing the application of HDACi and DNMTi to the damaged pulp to stimulate repair.

The Ability of Quantitative, Specific, and Sensitive Point-of-Care/Chair-Side Oral Fluid Immunotests for aMMP-8 to Detect Periodontal and Peri-Implant Diseases

The analysis of the disease-specific oral and systemic biomarkers in saliva and oral fluids (i.e., mouth rinse, gingival crevicular fluid (GCF), and peri-implantitis fluid (PISF)) is demanding. Several hosts and microbial factors may influence their expression, release, and levels. The type of saliva/oral fluids utilized for the diagnostics affects the analysis. High sensitivity and specificities together with sophisticated methods and techniques are essential for valuable outcome. We describe here recently developed practical, convenient, inexpensive, noninvasive, and quantitative mouth rinse and PISF/GCF/chair-side/point-of-care (PoC) lateral-flow aMMP-8 immunoassays (PerioSafe and ImplantSafe/ORALyser) to detect, predict, and monitor successfully the course, treatment, and prevention of periodontitis and peri-implantitis, respectively. The tests have been independently and successfully validated to differentiate periodontal and peri-implant health and disease in Finland, Germany, Netherland, Sweden, Turkey, Nigeria, Malawi, and USA. The clinical use of salivary/oral fluid biomarkers to identify oral and systemic conditions requires additional studies utilizing these noninvasive screening, diagnostic, and preventive aMMP-8 PoC/chair-side technologies.

Anti-rheumatic medication and salivary MMP-8, a biomarker for periodontal disease

OBJECTIVE

To investigate the impact of anti-rheumatic medications on salivary matrix metalloproteinase (MMP)-8 levels and MMP-8/TIMP (tissue inhibitor of MMPs)-1 ratio in patients with rheumatoid arthritis (RA) and periodontal findings during a 1-year follow-up.

MATERIALS AND METHODS

Salivary MMP-8 was measured by an immunofluorometric assay and TIMP-1 by an enzyme-linked immunosorbent assay of 53 patients with early untreated RA (ERA), naïve to synthetic disease modifying anti-rheumatic drugs (DMARDs), of 28 patients with chronic RA (CRA), candidates for biologic DMARDs and of 43 age- and sex-matched controls. Periodontal health was evaluated by bleeding on probing (BOP), pocket depth (PD), and periodontal inflammatory burden index (PIBI). Examinations were conducted twice for RA patients and once for controls.

RESULTS

Salivary MMP-8 level and MMP-8/TIMP-1 ratio associated positively with PIBI in patients with chronic RA (MMP-8: p < 0.001 at baseline, p = 0.002 after follow-up; MMP-8/TIMP-1 ratio p < 0.001, p = 0.003, respectively) and in controls (MMP-8: p = 0.010, MMP-8/TIMP-1 ratio: p = 0.010). Salivary MMP-8 levels were highest at the early stage of RA. The used DMARDs, synthetic or biologic, did not affect salivary MMP-8 concentrations.

CONCLUSIONS

The use of synthetic or biologic DMARDs did not affect salivary MMP-8 levels in RA patients regardless the duration of RA.

Bisphosfonate matrix metalloproteinase inhibitors for the treatment of periodontitis: An in vitro study

Periodontitis is an inflammatory disease caused by anaerobic bacteria, including Porphyromonas gingivalis. Lipopolysaccharide (LPS)‑stimulated persistent inflammation is responsible for an increase in matrix metalloproteinase (MMP) expression, resulting in periodontal tissue destruction. The aim of the present study was to investigate synthesized bisphosphonic MMP inhibitors, in an in vitro model consisting of human gingival fibroblasts exposed to LPS, and to compare the biological responses to those induced by zoledronate (ZA), a commercial bisphosphonate. MTT and lactate dehydrogenase (LDH) assays were used to measure cell viability and cytotoxicity, respectively. ELISA was performed to evaluate prostaglandin E2 (PGE2), interleukin (IL)6 and collagen secretion, while western blotting was used to analyze MMP expression. No effect on viability and low cytotoxicity were observed following treatment with bisphosphonate compounds. In the present study, treatment with compound 1 did not increase the release of PGE2 and IL6. Increased levels of collagen I secretion were reported when compound 3 and ZA were administered. An increase of MMP8 was observed following ZA treatment, while a decrease of MMP9 and MMP14 following treatment with compounds 1, 2 and ZA were reported. The performance of compound 1 was optimal in terms of cell viability. Compound 1 also did not induce inflammation, and had the ability to counteract LPS‑induced increases in MMP expression. These data suggested that compound 1 was the most suitable treatment to progress to an in vivo animal study, with the aim to confirm its use for the treatment of periodontitis.

Matrix metalloproteinase-8 levels in oral samples as a biomarker for periodontitis in the Chinese population: an observational study

BACKGROUND

Clinical evaluation of periodontal inflammation does not fully reflect the disease activity. Extensive studies have been conducted out on gingival crevicular fluid (GCF) components that might serve as potential diagnostic markers for periodontitis, among which matrix metalloproteinase-8 (MMP-8) has shown to be promising, but there were no studies for individuals in China. The aim of this study was to compare clinical diagnostic parameters and levels of active MMP-8 (aMMP-8) in GCF and oral rinse samples from the Chinese patients with varying degrees of periodontal inflammation.

METHODS

GCF and oral rinse samples were obtained from 60 participants into two groups, a periodontitis group and a control group, specified by the presence and number of pocket depths or attachment loss. The aMMP-8 levels in GCF and oral rinse samples was quantified by ELISA using specific monoclonal antibodies. Logistic and linear regression models were employed for testing the correlation between aMMP-8 levels and periodontal condition, as well as diagnostic sensitivity and specificity.

RESULTS

Periodontitis group (mean = 24.84 ng/ml) exhibited significantly higher aMMP-8 levels than control group in GCF (p < 0.001). The aMMP-8 levels in oral rinse samples ranged from 0.05 to 2.18 ng/ml, but differences were not statistically significant between the two groups (p > 0.1). Receiver operating characteristic curve analysis showed a highest threshold of 6.66, with a corresponding sensitivity and specificity of 0.8 and 0.9, respectively.

CONCLUSIONS

Measuring aMMP-8 levels in GCF may have potentiality for complementary early diagnosis of periodontal disease and inflammation in the Chinese population.

Associations of oral fluid MMP-8 with periodontitis in Swiss adult subjects

OBJECTIVE

MMP-8 is a prominent collagenase in periodontal disease. This cross-sectional study examined whether MMP-8 levels in saliva and gingival crevicular fluid (GCF) are associated with periodontitis in a Swiss population.

SUBJECTS AND METHODS

A total of 258 subjects (107 m, 151 f, mean age: 43.5 yr; range: 21-58 yr) acquired from the Swiss bone marrow donor registry participated in the study. Saliva and GCF samples were collected from subjects followed by a thorough dental and periodontal examination. MMP-8 levels were determined with immunofluorometric assay. Associations of MMP-8 levels with periodontal diagnosis, probing pocket depth (PPD) and bleeding on probing were statistically analysed with Pearson chi-square test, Spearman's rho and logistic regression analysis.

RESULTS

MMP-8 in GCF correlated with MMP-8 in saliva (p < .001). Periodontitis was more common (p < .001) among subjects with high levels of MMP-8 in saliva and/or GCF compared with subjects with low levels of MMP-8. Higher MMP-8 levels in GCF and saliva were associated with any periodontal diagnosis (mild, moderate or severe), greater PPD, and bleeding on probing (p < .05). When age, gender, smoking, body mass index, number of medications and decayed, missing and filled teeth were adjusted for, all observed associations remained statistically significant. The area under curve of receiver-operating characteristic was 0.67 for saliva and 0.71 for GCF.

CONCLUSION

Elevated MMP-8 levels both in saliva and GCF are associated with periodontitis in a normal adult population.

Diagnosing peri-implant disease using the tongue as a 24/7 detector

Our ability of screening broad communities for clinically asymptomatic diseases critically drives population health. Sensory chewing gums are presented targeting the tongue as 24/7 detector allowing diagnosis by "anyone, anywhere, anytime". The chewing gum contains peptide sensors consisting of a protease cleavable linker in between a bitter substance and a microparticle. Matrix metalloproteinases in the oral cavity, as upregulated in peri-implant disease, specifically target the protease cleavable linker while chewing the gum, thereby generating bitterness for detection by the tongue. The peptide sensors prove significant success in discriminating saliva collected from patients with peri-implant disease versus clinically asymptomatic volunteers. Superior outcome is demonstrated over commercially available protease-based tests in saliva. "Anyone, anywhere, anytime" diagnostics are within reach for oral inflammation. Expanding this platform technology to other diseases in the future features this diagnostic as a massive screening tool potentially maximizing impact on population health.Early detection of gum inflammation caused by dental implants helps prevent tissue damage. Here, the authors present a peptide sensor that generates a bitter taste when cleaved by proteases present in peri-implant disease, embed it in a chewing gum, and compare the probe to existing sensors using patient saliva.

Evaluation of Metalloproteinase-8 Levels in Crevicular Fluid of Patients with Healthy Implants or Periodontitis

Evaluation of periodontal and peri-implant tissue condition is mainly based on clinical examination and imaging diagnostics. Some data imply that Metalloproteinase-8 (MMP-8) level examination in peri-implant sulcular fluid (PISF) might be useful for evaluating the condition of peri-implant tissues and monitoring a development of peri-implant inflammation, including both mucositis and peri-implantitis. Hence, in this study, we decided to evaluate the level of MMP-8 in PISF obtained from patients without clinical symptoms of mucositis or peri-implantitis and compare it with MMP-8 level in gingival crevicular fluid (GCF) obtained from patients with healthy periodontium and those with varying severity of periodontitis. A total of 189 subjects were included in the study, and GCF/PISF samples were analysed for MMP-8 level by ELISA test. We documented that MMP-8 level in PISF obtained from patients without symptoms of mucositis or peri-implantitis was significantly higher not only than in GCF of periodontally healthy patients but also, which seems to be very interesting, than in GCF of patients with varying degrees of periodontal inflammation, consistent with earlier studies. Our observation might imply that monitoring of MMP-8 level in PISF could help to diagnose mucositis/peri-implantitis in an early stage, prior to clinical manifestations, which may allow for quick start of appropriate therapy.