Pulp Inflammation Diagnosis from Clinical to Inflammatory Mediators: A Systematic Review

Study on pulp metabolism of patients with pulpitis using ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry

BACKGROUND AND AIMS

Pulpitis, a pulp disease caused by caries, trauma, and other factors, has a high clinical incidence. This study focused on identifying possible metabolic biomarkers of pulpitis cases and analyzing the related metabolic pathways for providing a theoretical foundation to diagnose and prevent pulpitis.

MATERIALS AND METHODS

Pulp samples from 20 pulpitis cases together with 20 normal participants were analyzed with a serum metabolomics approach using ultra-high-performance liquid chromatography (UPLC)/Orbitrap mass spectrometry. Moreover, this work carried out multivariate statistical analysis for screening potential biomarkers of pulpitis.

RESULTS

Through biomarker analysis and identification, such as partial least squares discrimination analysis, orthogonal partial least squares discriminant analysis model establishment, correlation analysis, and biomarker pathway analysis, 40 biomarkers associated with 20 metabolic pathways were identified, including 20 upregulated and 20 downregulated metabolites. Those major biomarkers included oxoglutaric acid, inosine, citric acid, and PA(14:1(9Z)/PGD1). Among them, oxoglutaric acid and inosine were most significantly downregulated and had the highest correlation with pulpitis. Among these metabolic pathways, GABAergic synapse and alanine, aspartate, and glutamate metabolism were positively correlated with pulpitis. 4.

CONCLUSIONS

These biomarkers as well as metabolic pathways may offer the theoretical foundation to understand pulpitis pathogenesis and develop preventive drugs.

Discriminatory performance of the pulpal inflammatory biomarkers; Interleukin-8 and TNF-α in patients with symptoms indicative of reversible and irreversible pulpitis: A diagnostic accuracy study

AIM

The success of vital pulp treatment (VPT) procedures is dependent on an accurate diagnosis of the pulpal inflammatory condition. Compared with current subjective pulpal diagnostic tests, inflammatory molecular biomarkers involved in the pathogenesis of pulpitis represent potential objective indicators of the degree of pulpal inflammation. Therefore, the aim of this study was to quantify level of inflammatory biomarkers - Interleukin 8 (IL-8) and TNF-α in patients diagnosed with reversible pulpitis (RP), irreversible pulpitis (IR) and normal pulp (NP) and investigate their diagnostic accuracy in differentiating between healthy and inflamed conditions.

METHODOLOGY

This prospective, cross-sectional study enrolled 72 patients aged 14-53 years with extremely deep carious lesions after establishing a clinical diagnosis of RP (n = 42), symptomatic IR (n = 22) and NP (n = 8). 50 μL of pulpal blood sample was collected from all the patients using a micropipette after pulpal exposure. The level of IL-8 and TNF-α was assessed in pg/mL using enzyme-linked immunosorbent assays. Mann-Whitney U test was applied to establish the association between IL-8/TNF-α level and degree of pulp inflammation. Receiver operating curve (ROC) analysis was carried out to calculate area under the curve (AUC) for RP versus IR. Cut-off values were established using Youden's index.

RESULTS

IL-8 and TNF-α levels differed significantly between RP and IR groups (p ≤ .001). The median value of IL-8 in RP and IP groups was 259.8 pg/mL [187.5-310.0] and 1357.8 pg/mL [1036.7-2177.6] respectively. The AUC-ROC curve for RP versus IR was 0.997 with 95.5% sensitivity and 99.76% specificity. The median value of TNF-α in RP and IR groups was 75.4 pg/mL [62.7-95.8] and 157.6 pg/mL [94.1-347.3]. The AUC-ROC curve for TNF-α was 0.812 with a sensitivity and specificity of 59.1% and 92.1%, respectively. IL-8 and TNF-α levels were below detection levels for all NP samples.

CONCLUSION

This study showed that pulpal blood could provide an excellent medium for establishing pulpal diagnosis under extremely deep carious lesions. The selected cytokines, IL-8 and TNF-α, demonstrated excellent discriminatory performance for reversible and irreversible pulpitis. Future studies should correlate the IL-8/TNF-α levels with VPT treatment outcomes.

Design and evaluation of an MMP-9-responsive hydrogel for vital pulp therapy

OBJECTIVE

To design and evaluate a matrix metalloproteinase 9 (MMP-9)-responsive hydrogel for vital pulp therapy.

METHODS

A peptide linker with optimized sensitivity toward MMP-9 was crosslinked with 4-arm poly (ethylene glycol)-norbornene (PEG-NB) by thiol-norbornene photo-polymerization. This resulted in the formation of a hydrogel network in which the peptide IDR-1002 was incorporated. Hydrogel characterization and gelation kinetics were examined with Fourier-transform infrared spectroscopy, scanning electron microscopy, rheological testing, and swelling evaluation. Hydrogel degradation was examined through multiple exposure to pre-activated MMP-9, to simulate flare-ups of dental pulp inflammation. The IDR-1002 released from degraded hydrogels was measured with high-performance liquid chromatography. Effect of IDR-1002 released from hydrogels on one-week-old multispecies oral biofilms was evaluated using confocal laser scanning microscopy.

RESULTS

MMP-9-responsive, injectable, and photo-crosslinkable hydrogels were successfully synthesized. When hydrogel degradation and release of IDR-1002 were examined with exposure to pre-activated MMP-9, IDR-1002 release was significantly correlated with elevated levels of MMP-9 (p < 0.05). The effectiveness of IDR-1002 in killing bacteria in multispecies oral biofilms was significantly enhanced when the hydrogels were immersed in 10 nM or 20 nM pre-activated MMP-9, compared to immersion in phosphate-buffered saline (p < 0.05).

CONCLUSIONS

The MMP-9-responsive hydrogel is a promising candidate for on-demand delivery of bioactive agent in vital pulp therapy.

CLINICAL SIGNIFICANCE

MMP-9 is one of the most important diagnostic and prognostic biomarkers for pulpitis. An MMP-9-responsive hydrogel has potential to be used as an in-situ on-demand release system for the diagnosis and treatment of dental pulp inflammation.

Osteopontin interacts with dendritic cells and macrophages in pulp inflammation: Comprehensive transcriptomic analysis and laboratory investigations

AIM

To investigate novel diagnostic markers for pulpitis and validate by clinical samples from normal and inflamed pulp. To explore the relationship between diagnostic markers and immune cells or their phenotypes during pulp inflammation.

METHODOLOGY

Two microarray datasets, GSE77459 and GSE92681, and identified differential expression genes were integrated. To understand immune features, gene functions, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Disease Ontology (DO) and ImmuneSigDB Gene Set Enrichment Analysis (GSEA) were analysed. For predictive purposes, machine learning techniques were applied to detect diagnostic markers. Immune infiltration in inflamed pulp was studied using CIBERSORT. The relationship between diagnostic markers and immune cells was investigated and validated their gene expression in clinical samples from the normal or inflamed pulp by qRT-PCR. Finally, the correlation between one marker, secreted phosphoprotein 1 (SPP1), encoding osteopontin (OPN), and dendritic cells (DCs)/macrophages was identified via HE staining and multiplex immunohistochemistry. An in vitro inflammatory dental pulp microenvironment model of THP-1 macrophages cocultured with dental pulp cells derived conditioned media (DPCs-CM) to investigate OPN production and macrophage phenotypes was established.

RESULTS

Analysis revealed unique immunologic features in inflamed pulp. Three diagnostic markers for pulpitis: endothelin-1 (EDN1), SPP1, and purine nucleoside phosphorylase (PNP), and validated them using qRT-PCR were predicted. Multiplex immunohistochemistry demonstrated OPN co-localized with activated DCs and M2 macrophages during pulp inflammation. In vitro experiments showed that THP-1 macrophages produced the highest levels of OPN when stimulated with DPCs-CM derived from the 20 μg/mL LPS pre-conditioned group, suggesting an M2b-like phenotype by increasing surface marker CD86 and expression of IL6, TNFα, IL10, and CCL1 but not CCL17 and MerTK. Levels of CCL1 and IL10 elevated significantly in the macrophages' supernatant from the 20 μg/mL LPS pre-conditioned CM group. OPN was proven co-localizing with CD86 in the inflamed pulp by immunofluorescence.

CONCLUSIONS

The current findings suggest that OPN can serve as a promising biomarker for pulpitis, correlated with DCs and macrophages. OPN+ macrophages in the inflamed pulp are associated with M2b-like phenotypes. These insights offer the potential for improved diagnosis and targeted therapy.

Revolutionizing the diagnosis of irreversible pulpitis - Current strategies and future directions

BACKGROUND

Pulpitis primarily arises from the pulp space infection by oral microbiota. Vital pulp therapy is a minimally invasive approach that relies on assessing the severity of pulpal inflammation to facilitate repair. However, the current evaluation methods prescribed by the American Association of Endodontics are subjective, leading to ambiguity in assessment. Therefore, this review aims to explore molecular strategies for evaluating the severity of pulpal inflammation to accurately predict the success of pulp vitality preservation in clinical settings.

HIGHLIGHTS

This review was conducted by searching relevant keywords, such as irreversible pulpitis, pulpitis biomarkers, molecular diagnosis, inflammation, and genomic strategies, in databases such as PubMed, Web of Science, and Scopus to address the subjective nature of diagnosis. The data included in this review were collected up to April 2023. The literature search revealed well-documented limitations in clinically assessing the pulp inflammatory. Molecular approaches that aid in clinical differentiation between irreversible and reversible pulpitis may potentially enhance favorable outcomes in vital pulp therapy. Non-invasive diagnostic methods for pulpal assessment would also be valuable for determining whether the inflamed pulp is reversible, irreversible, or necrotic.

CONCLUSION

This review examines the various molecular diagnostic approaches that have revolutionized the medical field and are considered the most promising empirical methodologies for the proactive detection of pulpal diseases. This review provides comprehensive insights into the current diagnostic methods, associated challenges, next-generation strategies, and future directions for diagnosing the severity of pulp inflammation.

Antimicrobial Peptide- and Dentin Matrix-Functionalized Hydrogel for Vital Pulp Therapy via Synergistic Bacteriostasis, Immunomodulation, and Dentinogenesis

The preservation of vital pulps is crucial for maintaining the physiological functions of teeth; however, vital pulp therapy (VPT) of pulpitis teeth remains a substantial challenge due to uncontrolled infection, excessive inflammation, and limited regenerative potential. Current pulp capping agents have restricted effects in the infectious and inflammatory microenvironment. To address this, a multifunctional hydrogel (TGH/DM) with antibacterial, immunomodulatory, and mineralization-promoting effects is designed. The antimicrobial peptide (AMP) and demineralized dentin matrix are incorporated into the hydrogel, achieving sustainable delivery of AMP and a cocktail of growth factors. In vitro results show that TGH/DM could kill endodontic microbiota, ameliorate inflammatory responses of human dental pulp stem cells (hDPSCs), and prompt odontogenic differentiation of inflammatory hDPSCs via activation of peroxisome proliferator-activated receptor gamma. In vivo results suggest that TGH/DM is capable of inducing M2 phenotype transformation of macrophages in mice and fostering the regeneration of the dentin-pulp complex in inflamed pulps of beagle dogs. Overall, this study first proposes the synergistic regulation of AMP and tissue-specific extracellular matrix for the treatment of pulpitis, and the advanced hydrogel provides a facile and effective way for VPT.

Expression of Selected Inflammatory Mediators with Different Clinical Characteristics of Pulpal Inflammation

INTRODUCTION

Accurately diagnosing the state of dental pulp is crucial when addressing tooth pain to determine the best treatment approach. This study aimed to investigate the concentration of inflammatory mediators in the dental pulp of mature teeth that have been exposed via caries but show no signs of apical periodontitis.

METHODS

Samples of pulpal blood from adults with mature teeth responsive to pulp testing and have carious pulp exposures were obtained. These samples were analyzed for 12 inflammatory cytokines and other inflammatory proteins using the Luminex assay platform. Clinical factors were correlated with cytokine levels, and statistical analysis was performed to evaluate the impact of these factors on cytokine expression.

RESULTS

Of the 36 patients that were included, 44.44% took pain medications, 33.33% had prolonged pulpal bleeding, 41.67% felt spontaneous pain, and 72.22% were diagnosed with symptomatic irreversible pulpitis. Significant correlations existed between presenting pain scores and levels of interleukin (IL)-1α, IL-6, and IL-8 (P < .05). Factors like analgesic medication intake, pain to percussion, pain to thermal testing, spontaneous pain, and nocturnal pain were significantly associated with higher levels of specific inflammatory proteins. No significant associations were observed with pain to palpation, bleeding time, or pulpal diagnosis.

CONCLUSIONS

Inflammatory proteins, including cytokine levels may play a critical role in characterizing pulpal inflammation. Future studies should investigate the role of these potential biomarkers in determining the diagnosis of pulpitis and the prognosis of vital pulp therapy.

Anti-inflammatory effect of luteoloside against methylglyoxal induced human dental pulp cells

PURPOSE

The aim of this study was to investigate whether luteoloside, a flavonoid, could protect human dental pulp cells (HDPCs) against inflammation and oxidative stress induced by methylglyoxal (MGO), one of the advanced glycated end products (AGE) substances.

METHODS

HDPCs were stimulated with MGO and treated with luteoloside. MTT assay was used to determine cell viability. Protein expression was measured via western blotting. Reactive oxygen species (ROS) were measured with a Muse Cell Analyzer. Alkaline phosphatase activity (ALP) and Alizarin red staining were used for mineralization assay.

RESULTS

Luteoloside down-regulated the expression of inflammatory molecules such as ICAM-1, VCAM-1, TNF-α, IL-1β, MMP-2, MMP-9, and COX-2 in MGO-induced HDPCs without showing any cytotoxicity. It attenuated ROS formation and enhanced osteogenic differentiation such as ALP activity and Alizarin red staining in MGO-induced HDPCs. Overall, luteoloside showed protective actions against inflammation and oxidative stress in HDPCs induced by MGO through its anti-inflammatory, anti-oxidative, and osteogenic activities by down-regulating p-JNK in the MAPK pathway.

CONCLUSION

These results suggest that luteoloside might be a potential adjunctive therapeutic agent for treating pulpal pathological conditions in patients with diabetes mellitus.

Differences of serum glucose and lipid metabolism and immune parameters and blood metabolomics regarding the transition cows in the antepartum and postpartum period

This study aims to investigate differences in metabolism regarding the transition cows. Eight cows were selected for the test. Serum was collected on antepartum days 14th (ap14) and 7th (ap7) and postpartum days 1st (pp1), 7th (pp7), and 14th (pp14) to detect biochemical parameters. The experiment screened out differential metabolites in the antepartum (ap) and postpartum (pp) periods and combined with metabolic pathway analysis to study the relationship and role between metabolites and metabolic abnormalities. Results: (1) The glucose (Glu) levels in ap7 were significantly higher than the other groups (p < 0.01). The insulin (Ins) levels of ap7 were significantly higher than pp7 (p = 0.028) and pp14 (p < 0.01), and pp1 was also significantly higher than pp14 (p = 0.016). The insulin resistance (HOMA-IR) levels of ap7 were significantly higher than ap14, pp7, and pp14 (p < 0.01). The cholestenone (CHO) levels of ap14 and pp14 were significantly higher than pp1 (p < 0.01). The CHO levels of pp14 were significantly higher than pp7 (p < 0.01). The high density lipoprotein cholesterol (DHDL) levels of pp1 were significantly lower than ap14 (p = 0.04), pp7 (p < 0.01), and pp14 (p < 0.01), and pp14 was also significantly higher than ap14 and ap7 (p < 0.01). (2) The interferon-gamma (IFN-γ) and tumor necrosis factor α (TNF-α) levels of ap7 were significantly higher than pp1 and pp7 (p < 0.01); the immunoglobulin A (IgA) levels of pp1 were significantly higher than ap7 and pp7 (p < 0.01); the interleukin-4 (IL-4) levels of pp7 were significantly higher than ap7 and pp1 (p < 0.01), the interleukin-6 (IL-6) levels of ap7 and pp1 were significantly higher than pp7 (p < 0.01). (3) Metabolomics identified differential metabolites mainly involved in metabolic pathways, such as tryptophan metabolism, alpha-linolenic acid metabolism, tyrosine metabolism, and lysine degradation. The main relevant metabolism was concentrated in lipid and lipid-like molecules, organic heterocyclic compounds, organic acids, and their derivatives. The results displayed the metabolic changes in the transition period, which laid a foundation for further exploring the mechanism of metabolic abnormalities in dairy cows in the transition period.

The mitochondrial-endoplasmic reticulum co-transfer in dental pulp stromal cell promotes pulp injury repair

Dental pulp injury remains a clinical challenge with limited therapeutic approaches. In the present study, we sought to prove that dental pulp stromal cells (DPSCs) mitochondrial transfer could promote dental pulp injury repair and endoplasmic reticulum (ER)-mitochondrial contacts have a significant regulatory effect on mitochondrial transfer. Healthy DPSCs were co-cultured directly or indirectly with injured DPSCs in the first molar of 1-2 month SD rats or in vitro. Mitochondrial transfer was observed after 24 h of co-culture using fluorescence microscopy and live cell workstation. After co-culture for 1W, 8-OhdG immunofluorescence, mitochondrial membrane potential and total oxidant status/total antioxidant status were used to detect the mitochondrial function of injured DPSCs before and after mitochondrial transfer. Subsequently, mitochondria-ER co-transfer was regulated by modulating mitochondria-ER binding in healthy DPSCs, and the results of GRP78 and CHOP in DPSCs, and PDI immunofluorescence and haematoxylin and eosin staining of pulp tissue were analysed to clarify the effects of modulating mitochondria-ER co-transfer on endoplasmic reticulum stress (ERS), and on pulp injury repair. Fluorescence microscopy and live cell workstation results showed significant mitochondrial transfer between DPSCs. Meanwhile, mitochondrial transfer significantly restored mitochondrial function in injured DPSCs. By modulating mitochondrial-ER binding, the efficiency of mitochondrial transfer between DPSCs was significantly affected and had an impact on ERS in injured cells. Mitochondrial transfer of DPSCs significantly promotes pulpal injury repair and functional recovery of damaged DPSCs, and mitochondrial transfer of DPSCs is regulated by mitochondria-ER binding.

Investigating In Situ Expression of Neurotrophic Factors and Partner Proteins in Irreversible Pulpitis

INTRODUCTION

In situ assessments of neurotrophic factors and their associated molecular partners have not been explored to date, particularly in humans. The present investigation aimed to explore the expressional dysregulation of neurotrophic factors (nerve growth factor [NGF], brain derived neurotrophic factor [BDNF], and NT4/5), their receptors (TrkA and TrkB), and their modulators (USP36 and Nedd4-2) directly in irreversibly inflamed human pulp tissues.

METHODS

Forty samples each of healthy and irreversibly inflamed pulp were extirpated for the study. Immunohistochemical examinations were carried out for the anatomic changes and expression of neurotrophic factors and partner proteins. Expression was digitally quantified using the IHC profiler module of ImageJ and deduced as optical density. Statistical analyses were carried out by GraphPad Prism.

RESULTS

Decrease in nuclear and vessel diameters was observed in irreversibly inflamed pulp tissues. NGF and BDNF were found to be significantly upregulated in symptomatic irreversible pulpitis (SIP), whereas no significant difference was observed in the expression of TrkA and TrkB. Expression of Nedd4-2, USP36, and TrkA was found positively correlated with the NGF in healthy pulp tissues. However, in SIP, positive correlation was only observed between the expression of USP36 and NGF. Among the ligands, BDNF expression was found positively correlated with NGF in healthy pulp but not with NT4/5. In the case of SIP, no correlation was observed between any neurotrophic factors.

CONCLUSIONS

Upregulation of NGF, BDNF, USP36 and Nedd4-2 in SIP indicates dysregulation in the molecular events underlying the disease biology and could be exploited as potential markers for the disease diagnosis.

Discovery of (S)-flurbiprofen-based novel azine derivatives as prostaglandin endoperoxide synthase-II inhibitors: Synthesis, in-vivo analgesic, anti-inflammatory activities, and their molecular docking

The anti-inflammatory and analgesic drugs currently used are associated with several adverse effects and found to be highly unsafe for long-term use. Currently, nineteen novel bis-Schiff base derivatives (1-19) of flurbiprofen have been designed, prepared and assessed for in-vivo analgesic, anti-inflammatory and in vivo acute toxicity evaluation. The structures of the acquired compounds were deduced through modern spectroscopic techniques including HR-ESI-MS, 13C-, and 1H NMR. Amongst the series, compounds 7, 9, and 10 attributed potent activities with 93.89, 92.50, and 90.47% decreased edema, respectively compared to flurbiprofen (90.01%), however, compounds 11 and 15 exhibited significant activity of 90.00% decrease. Out of them, fourteen compounds (1-6, 8, 12-14, and 16-19) displayed good activity in the range of 68.96-86.95%. In case of an analgesic study, all the derivatives significantly (p 0.001) increased the pain threshold time particularly compound 7 had the best analgesic effect (24 ± 2.08 s) in comparison with flurbiprofen (21.66 ± 2.02 s) using hot plate test. Similarly, in the acetic acid-induced writhing test, compound 7 determined a potent inhibitory effect (60.47 %) close to flurbiprofen (59.28%). All the synthesized derivatives were found safe up to the dose of 30 mg/kg, in acute toxicity study. On a molecular scale, the synthesized compounds were modeled through a ligand-based pharmacophore study and molecular docking to have insight into the different possible interactions leading to high inhibition levels against the COX-2 enzyme.

Increased IL-12p70 and IL-8 Produced by Monocytes in Response to Streptococcus spp. and Actinomyces spp. Causals of Endodontic Primary Infections

We sought to evaluate the effect of endodontic-causative microorganisms of primary infections on mononuclear cells such as CD14+, CD4+, CD8+, CD19+ and Tregs Foxp3+. Facultative anaerobic microorganisms were isolated from radicular conducts and peripheral blood samples, which were taken from patients with primary infections. Cellular cultures were performed with peripheral blood mononuclear cells (PBMC) with and without Actinomyces spp. and Streptococcus spp. during 48, 72, and 96 h of contact in culture (concentration 5 × 105 cells/well) in a round plate bound with 48 wells. Later, PBMC was collected for analysis by flow cytometry, with the monoclonal antibodies αCD14, αCD4, αCD8, αCD19 and αFoxp3, and acquired using an FACSCanto II cytometer. The supernatant of cellular cultures was analyzed for the quantification of inflammatory cytokines. Data analysis was performed in FlowJo v10.8.2 and FCAPArray software, and statistical analysis was performed using GraphPad v5.0. software. We observed an increase in the percentage of CD14+ cells in patients at different hours of cellular culture in the presence of both Actinomyces spp. and Streptococcus spp. microorganisms, compared to healthy controls. This study demonstrates the role played by the innate immune system in the pathogeny of endodontic primary infections, explaining the effects that generate the more common microorganisms in this oral pathology.

Symptomatic Irreversible Pulpitis Induces Increased Levels of Human NLRP3 in Gingival Crevicular Fluid Compared to Saliva: A Case Control Observational Study

INTRODUCTION

The goal of this case-control observational study was to compare the levels of the human nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing-3 (NLRP3) protein in the saliva and gingival crevicular fluid (GCF) of patients with symptomatic irreversible pulpitis (SIP) and healthy controls.

METHODS

The 16 patients in the control group were matched with the 16 patients in the SIP group to create a total of 32 patients. In addition to saliva, GCF (n = 48) samples were collected from the involved tooth (n = 16), contralateral tooth (n = 16), and adjacent tooth (n = 16) in the SIP group. Saliva and GCF were taken from the healthy group as a baseline. An independent t-test was used for statistical analysis. The random-intercept model was used to compare the average NLRP3 levels in the SIP tooth, adjacent tooth, and contralateral tooth taking age as a covariate, and the P value was adjusted using Bonferroni correction.

RESULTS

There were significantly higher levels of NLRP3 in the saliva of SIP patients (1.78 ± 1.14 ng/ml) compared to the healthy control (0.70 ± 0.70 ng/ml) and in the GCF of the involved tooth (5.72 ± 0.63 ng/ml) compared to healthy people (1.60 ± 0.42 ng/ml) (P < .001). In SIP patients the mean difference of NLRP3 levels between SIP and contralateral teeth was significant at 4.13 ng/ml (95% confidence interval, 3.52-4.70 P < .001) and a mean difference between adjacent teeth and contralateral teeth was significant at 3.53 ng/ml [95% confidence interval, 2.94-4.12 P < .001]. The NLRP3 in GCF and saliva had a negative association in the affected tooth but a negligible correlation in healthy controls.

CONCLUSION

The NLRP3 inflammasome has the potential to be employed as a molecular diagnostic biomarker for pulpal disorders.

Pain after emergency treatments of symptomatic irreversible pulpitis and symptomatic apical periodontitis in the permanent dentition: a systematic review of randomized clinical trials

Background

Symptomatic irreversible pulpitis (SIP) or symptomatic apical periodontitis (SAP) are two painful conditions often warranting emergency treatment. The most common emergency treatments supported by evidence are pulpotomy and pulpectomy and are normally performed under time-constrained circumstances. However, there is no strong evidence of which treatment suggested in literature a clinician can use to reduce endodontic pain effectively. Therefore, the aim of this systematic review is to investigate the present knowledge on postoperative pain related to the two types of emergency treatments available for treating SIP and SAP.

Methods

Randomized controlled trials investigating postoperative pain after emergency treatments (pulpotomy and/or pulpectomy) on permanent dentition with signs and symptoms of SIP and/or SAP were searched in three major databases from 1978 until 2022. Risk of bias was assessed with Cochrane's tool.

Results

Only five studies fulfilled the inclusion criteria. The included studies indicated that pulpotomy and pulpectomy are both suitable treatment options for SAP and SIP, as they provide sufficient alleviation of pain in permanent dentition. However, inconsistent results were found between the included trials on which emergency treatment is more effective in reducing pain. Cochrane's tool revealed that the studies had a low risk of bias. Limitations found in the design of the included randomized control trials decreased the level of evidence. None of the included studies accounted for essential confounding variables, such as factors affecting pain (including the psychological aspects). Moreover, possible non-odontogenic pain was not assessed, and therefore, it was not excluded; hence, affecting the internal validity of the studies.

Conclusion

There are controversies within the available randomized control trials on which treatment is most effective in reducing emergency pain. This could be due to some weaknesses in the design of the clinical trials. Thus, further well-designed studies are warranted to draw conclusions on which emergency treatment is more effective in reducing pain.

Systematic Review Registration

PROSPERO (CRD42023422282).

Molecular biomarkers for objective assessment of symptomatic pulpitis: A systematic review and meta-analysis

BACKGROUND

Inflammatory biomarkers are potentially useful targets for pulpal diagnostic tests that can identify pulp status and predict vital pulp treatment (VPT) outcome, however, their accuracy is unknown.

OBJECTIVES

(1) Calculate sensitivity, specificity and diagnostic odds ratio (DOR) of previously investigated pulpitic biomarkers; (2) Determine if biomarker levels discriminate between clinical diagnoses of pulpitis based on the presence or absence of spontaneous pain (3) Evaluate if biomarker level can predict VPT outcome.

METHODS

Searches: PubMed/MEDLINE, Ovid SP, Cochrane Central Register of Controlled Trials (CENTRAL), International Clinical Trials Registry Platform (ICTRP), ClinicalTrials.gov, Embase, Web of Science and Scopus in May 2023.

INCLUSION

prospective and retrospective observational studies and randomized trials. Participants were humans with vital permanent teeth and a well-defined pulpal diagnosis.

EXCLUSION

deciduous teeth, in vitro and animal studies. Risk of bias was assessed with modified-Downs and Black quality assessment checklist. Meta-analysis was performed using bivariate random effect model in Meta-DiSc 2.0 and RevMan and the quality of the evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

Fifty-six studies were selected, reporting >70 individual biomolecules investigating pulpal health and disease at the gene and protein level. Most studies were of low and fair quality. Among the biomolecules investigated, IL-8 and IL-6 demonstrated a level of diagnostic accuracy with high sensitivity, specificity and DOR to discriminate between healthy pulps and those exhibiting spontaneous pain suggestive of IRP (low-certainty evidence). However, none was shown to have high DOR and the ability to discriminate between pulpitic states (very low certainty evidence). Limited data suggests high levels of matrix metalloproteinase 9 correlate with poorer outcomes of full pulpotomy.

DISCUSSION

The inability of identified molecular inflammatory markers to discriminate between dental pulps with spontaneous and non-spontaneous pain should shift the focus to improved study quality or the pursuit of other molecules potentially associated with healing and repair.

CONCLUSIONS

Low-quality evidence suggests IL-8 and IL-6 demonstrated level of diagnostic accuracy to discriminate between healthy pulps and those exhibiting spontaneous pain. There is a need for standardized biomarker diagnostic and prognostic studies focusing on solutions that can accurately determine the degree of pulp inflammation.

REGISTRATION

PROSPERO CRD42021259305.

Effectiveness of diagnosing pulpitis: A systematic review

BACKGROUND

The diagnosis of the status of the inflamed pulp is essential in clinical diagnosis and treatment provision. There are a limited number of well-designed and well-executed clinical trials on the diagnosis of the true status of the pulp.

OBJECTIVES

Three PICO questions were formulated and agreed a priori by the European Society of Endodontology to evaluate the clinical tests for sensibility testing, determination of biomarkers and pulp bleeding with regard to their suitability to correctly diagnose the condition of the pulp tissue for the development of S3-Level guidelines.

METHODS

A literature search was conducted using PubMed, Clarivate Analytics' Web of Science, Scopus, Google Scholar and Cochrane Central Register of Controlled Trials from inception to 21 January 2022. Additionally, a hand search was performed, and the contents of the major subject journals were also examined. Eligibility criteria followed the proposed PICO questions. Two independent reviewers were involved in study selection, data extraction and appraising the included studies; disagreements were resolved by a third reviewer. The risk of bias was assessed by the QUADAS-2 tool for diagnostic accuracy studies, the Newcastle-Ottawa scale for noncomparative, nonrandomized studies and the Newcastle-Ottawa Quality Assessment scale adapted for cross-sectional studies.

RESULTS

In total, 28 studies out of 29 publications were considered eligible and were included in the review. Twelve studies were identified to investigate the diagnostic accuracy of the pulp vitality. Ten studies fulfilled the criteria to evaluate the diagnostic accuracy of the pulpal conditions, while 6 studies investigating the expression of biomarkers were eligible. Three studies addressing the prognostic factors and therapeutic interventions relating to pulpal status were included.

DISCUSSION

The core problem in pulp diagnostics is that a reliable reference standard is lacking under clinical conditions. Based on limited evidence, the most promising current approach seems to define a combination of different clinical tests and symptoms, probably in future including molecular diagnosis ("diagnostic package") will be required to ascertain the best possible strategy to clinically diagnose true pulpal conditions.

CONCLUSIONS

The effectiveness of diagnosing pulpitis is low due to limited scientific evidence regarding the accuracy and reproducibility of diagnostic tests. There is a lack of evidence to determine the true status of the pulp or to identify prognostic indicators allowing for a reliable pre-operative estimation of the outcome of vital pulp treatment.

REGISTRATION

PROSPERO database (CRD42021265366).

The Role of Asiatic Acid in Preventing Dental Pulp Inflammation: An in-vivo Study

Purpose

Acute dental pulp inflammation necessitates early treatment to alleviate inflammation and pain. In the inflammatory phase, a substance is required to lower the inflammatory mediators and reactive oxygen species that play a crucial role in that phase. Asiatic acid is a natural triterpene obtained from the Centella asiatica plant with a high antioxidant value. This study examined the effect of Asiatic acid's antioxidant, anti-inflammatory, and antinociceptive properties on dental pulp inflammation.

Methods

The research is an experimental laboratory, with a post-test only with a control group design. The study utilised 40 male Wistar rats weighing 200-250 grams and aged 8-10 weeks. Rats were divided into five groups (control, eugenol, Asiatic Acid 0.5%; 1%; 2% group). Dental pulp inflammation was created in the maxillary incisor after six hours of administration of lipopolysaccharides (LPS). The dental pulp treatment then continued with the administration of eugenol and three different Asiatic acid concentrations (0.5%, 1% and 2%). In the next 72 hours, the teeth were biopsied, and the dental pulp was analysed using the enzyme-linked immunosorbent assay (ELISA) to measure the level of MDA, SOD, TNF-α, beta-endorphins and CGRP. Histopathological examination and the Rat Grimace Scale were utilised to determine the level of inflammation and pain, respectively.

Results

The effect of Asiatic Acid on MDA, TNF-α, and CGRP levels decreased significantly compared to the control group (p=<0.001). On the SOD and beta-endorphin levels, Asiatic acid treatment resulted in a considerable rise (p =<0.001).

Conclusion

Due to its antioxidant, anti-inflammatory, and antinociceptive characteristics, Asiatic acid can reduce inflammation and pain in acute pulp inflammation due to its ability to decrease MDA, TNFα, and CGRP levels while raising SOD and beta-endorphin levels.

Identification of the characteristics of infiltrating immune cells in pulpitis and its potential molecular regulation mechanism by bioinformatics method

OBJECTIVE

The inflammation of dental pulp will also trigger an immune response. The purpose of this study is to demonstrate the immune cell's function and explore their regulatory molecules and signal pathways in pulpitis.

METHOD

The CIBERSORTx method was used to quantitatively analyze 22 types of immune cells infiltrating in the GSE77459 dataset of dental pulp tissues. The immune-related differential genes (IR-DEGs) were further screened and enriched for the GO and KEGG pathways. Protein-protein interaction (PPI) networks were constructed and the hub IR-DEGs were screened. Finally, we constructed the regulatory network of hub genes.

RESULTS

The GSE77459 dataset screened 166 IR-DEGs and was enriched for three signal pathways involved in pulpitis development: chemokine signaling, TNF signaling, and NF-κB signaling. Significant differences in immune cell infiltration were observed between normal and inflamed dental pulp. The proportions of M0 macrophages, neutrophils, and follicular helper T cells were significantly higher than that of the normal dental pulp, while the proportions of resting mast cells, resting dendritic cells, CD8 T cells, and monocytes were significantly lower. The random forest algorithm concluded that M0 macrophages and neutrophils were the two most important immune cells. We identified five immune-related hub genes IL-6, TNF-α, IL-1β, CXCL8, and CCL2. In addition, IL-6, IL-1β, and CXCL8 are highly correlated with M0 macrophages and neutrophils, and the five hub genes have many shared regulatory molecules: four miRNAs and two lncRNAs, three transcription factors.

CONCLUSION

Immune cell infiltration plays an important role in pulpitis among which M0 macrophages and neutrophils are the most significant immune cells. IL-6, TNF-α, IL-1, CXCL8, and CCL2 may be essential molecule of the immune response regulation network in pulpitis. This will help us understand the immune regulatory network in pulpitis.

Concentrated growth factor combined with iRoot BP Plus promotes inflamed pulp repair: an in vitro and in vivo study

BACKGROUND

Platelet concentrates combined with calcium silicate cements may promote reparative dentin formation. However, few studies have reported their effect on dental pulp inflammation. This study aimed to evaluate the effects of concentrated growth factor (CGF) combined with iRoot BP Plus on inflammatory human dental pulp stem cells (hDPSCs) in vitro and inflamed pulp in rats in vivo.

METHODS

The proliferation of LPS-stimulated hDPSCs treated with 50% CGF with/without 25% iRoot BP Plus was evaluated using Cell Counting Kit-8 on days 1, 4 and 7. The expression of genes associated with inflammation on day 1 and differentiation on day 14 was analysed by real-time polymerase chain reaction. The exposed pulp of rat maxillary molars was injected with 10 mg/mL LPS and directly capped with CGF membrane with/without iRoot BP Plus extract for 1, 7 and 28 days. The teeth were subjected to histologic analyses and immunohistochemistry.

RESULTS

The proliferation rates of the inflammatory hDPSCs after the combination treatment were significantly higher than those after the other treatments on days 4 and 7 (P < 0.05). IL-1β, IL-6, and TNF-α levels were increased in inflammatory hDPSCs but decreased after treatment with CGF combined with iRoot BP Plus extract, whereas IL-4 and IL-10 showed the opposite expression patterns. Expression of the odontogenesis-related genes OCN, Runx2, and ALP was dramatically enhanced by combined treatment with CGF and iRoot BP Plus extract. In rat pulp, the average inflammation scores of the CGF and CGF-iRoot BP Plus groups significantly decreased in comparison with those of the LPS group (P < 0.05), and the CGF-iRoot BP Plus group had more reparative dentin than the CGF and BP groups. Immunohistochemical staining showed fewer M1 macrophages on day 1 and more M2 macrophages on day 7 in the CGF-iRoot BP Plus group than in the other groups.

CONCLUSIONS

The combination of CGF and iRoot BP Plus showed a synergistic effect on anti-inflammatory potential and promoted greater pulp healing than CGF or iRoot BP Plus alone.

MicroRNA-146b-5p Suppresses Pro-Inflammatory Mediator Synthesis via Targeting TRAF6, IRAK1, and RELA in Lipopolysaccharide-Stimulated Human Dental Pulp Cells

MicroRNA-146b-5p (miR-146b-5p) is up-regulated during and to suppress the inflammation process, although mechanisms involved in the action of miR-146b-5p have not been fully elucidated. This study examined the anti-inflammation effects of miR-146b-5p in lipopolysaccharide (LPS)-stimulated human dental pulp cells (hDPCs). An increase in human miR-146b-5p (hsa-miR-146b-5p) expression following the mRNA expression of pro-inflammatory cytokines was observed in LPS-stimulated hDPCs. The expression of hsa-miR-146b-5p and pro-inflammatory cytokines was down-regulated by a nuclear factor-kappa B (NF-κB) inhibitor, and the expression of hsa-miR-146b-5p was also decreased by a JAK1/2 inhibitor. Enforced expression of hsa-miR-146b-5p abolished phosphorylation of NF-κB p65 and down-regulated the expression of pro-inflammatory cytokines and NF-κB signaling components, such as interleukin-1 receptor-associated kinase 1 (IRAK1), tumor necrosis factor receptor-associated factor 6 (TRAF6), and REL-associated protein involved in NF-κB (RELA). Expression of rat miR-146b-5p (rno-miR-146b-5p) and pro-inflammatory cytokine mRNA was also up-regulated in experimentally-induced rat pulpal inflammation in vivo, and rno-miR-146b-5p blocked the mRNA expression of pro-inflammatory mediators and NF-κB signaling components in LPS-stimulated ex vivo cultured rat incisor pulp tissues. These findings suggest that the synthesis of miR-146b-5p is controlled via an NF-κB/IL6/STAT3 signaling cascade, and in turn, miR-146b-5p down-regulates the expression of pro-inflammatory mediators by targeting TRAF6, IRAK1, and RELA in LPS-stimulated hDPCs.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation

OBJECTIVES

To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment.

MATERIALS AND METHODS

DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA.

RESULTS

After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05).

CONCLUSION

Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA.

CLINICAL RELEVANCE

The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

Biological Properties of Dental Pulp Stem Cells Isolated from Inflamed and Healthy Pulp and Cultured in an Inflammatory Microenvironment

INTRODUCTION

The aim of this study was to assess whether the biological characteristics of dental pulp stem cells (DPSCs), such as viability, adhesion to dentin, mineralization, and release of immunomodulatory cytokines, are affected by the inflammatory status of the donor tissue and/or the sustained inflammatory environment.

METHODS

DPSCs were isolated from pulps from 3 caries-free teeth (healthy or hDPSCs), and from 3 teeth with irreversible pulpitis or deep caries (unhealthy DPSCs or uDPSCs). The cells were cultured in odontogenic and osteogenic media with or without lipopolysaccharides. Viability was analyzed by MTT assay at days 1, 3, 5, and 7; adhesion to dentin was evaluated through an environmental scanning electron microscope after 48 hours and through MTT assay; mineralization was analyzed with alizarin red staining after 21 days; and the release of proinflammatory (interleukin 6) and immunosuppressive cytokines (interleukin 10) was measured with the enzyme-linked immunosorbent assay after 24 hours and 7 days.

RESULTS

The inflammatory status of the pulp significantly reduced the viability and mineralization capacity of the DPSCs, although it did not affect the adhesion capacity to dentin or the secretion of the proinflammatory interleukin. The inflammatory microenvironment (lipopolysaccharide) only had a significant impact on the secretion of interleukin 6, which was augmented after 7 days.

CONCLUSIONS

The inflammatory status of the dental pulp should be taken into account when the use of DPSCs is intended either for research and/or for application in reparative or regenerative therapies.

The protective role of curcumin in human dental pulp stem cells stimulated by lipopolysaccharide via inhibiting NF-κB p65 phosphorylation to suppress NLRP3 inflammasome activation

OBJECTIVES

This study aims to investigate the anti-inflammatory effect of curcumin and underlying mechanisms regarding the modulation of the nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome in human dental pulp stem cells (hDPSCs).

MATERIALS AND METHODS

The impact of curcumin on the viability of hDPSCs was evaluated. The effect of curcumin on the expression of IL-1β and NLRP3 in hDPSCs stimulated by lipopolysaccharide (LPS) was assessed. Then, LPS-primed hDPSCs were pre-treated with curcumin before ATP triggering NLRP3 inflammasome activation, and NLRP3 inflammasome-related mediators were assessed. The mechanism of curcumin inactivation of LPS plus ATP-induced inflammasome associated with NF-κB pathway was explored. The NF-κB pathway related pro-inflammatory mediators at mRNA and protein levels were evaluated. The expression of NF-κB p65 and phosphorylation p65 was visualized after curcumin or NF-κB inhibitor administrating respectively in hDPSCs with an activated NLRP3 inflammasome. Statistical analysis was performed.

RESULTS

While curcumin at the concentration of 0.5-5 μM showed no obvious impact on the viability of hDPSCs, it significantly decreased IL-1β and NLRP3 mRNA expression in LPS-induced hDPSCs in a dose-dependent manner. Curcumin significantly inhibited the LPS plus ATP-primed NLRP3 inflammasome activation in hDPSCs (NLRP3, ASC, caspase-1, and IL-1β). Curcumin evidently attenuated the LPS plus ATP-induced expression of NF-κB pathway-related pro-inflammatory mediators (IL-6, IL-8, TNF-α, and COX-2). Furthermore, curcumin effectively reduced p65 phosphorylation, which acts as an NF-κB inhibitor in hDPSCs with an activated NLRP3 inflammasome.

CONCLUSIONS

Curcumin pre-treatment may exert an anti-inflammatory role via inactivation of the NLRP3 inflammasome by inhibiting NF-κB p65 phosphorylation in cultured hDPSCs.

CLINICAL RELEVANCE

Curcumin may have therapeutic potential in pulp inflammation.

Identification of key module and hub genes in pulpitis using weighted gene co-expression network analysis

BACKGROUND

Pulpitis is a common disease mainly caused by bacteria. Conventional approaches of diagnosing the state of dental pulp are mainly based on clinical symptoms, thereby harbor deficiencies. The accurate and rapid diagnosis of pulpitis is important for choosing the suitable therapy. The study aimed to identify pulpits related key genes by integrating micro-array data analysis and systems biology network-based methods such as weighted gene co-expression network analysis (WGCNA).

METHODS

The micro-array data of 13 inflamed pulp and 11 normal pulp were acquired from Gene Expression Omnibus (GEO). WGCNA was utilized to establish a genetic network and categorize genes into diverse modules. Hub genes in the most associated module to pulpitis were screened out using high module group members (MM) methods. Pulpitis model in rat was constructed and iRoot BP plus was applied to cap pulp. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used for validation of hub genes.

RESULTS

WGCNA was established and genes were categorized into 22 modules. The darkgrey module had the highest correlation with pulpitis among them. A total of 5 hub genes (HMOX1, LOX, ACTG1, STAT3, GNB5) were identified. RT-qPCR proved the differences in expression levels of HMOX1, LOX, ACTG1, STAT3, GNB5 in inflamed dental pulp. Pulp capping reversed the expression level of HMOX1, LOX, ACTG1.

CONCLUSION

The study was the first to produce a holistic view of pulpitis, screen out and validate hub genes involved in pulpitis using WGCNA method. Pulp capping using iRoot BP plus could reverse partial hub genes.

Stimulation phosphatidylinositol 3-kinase/protein kinase B signaling by Porphyromonas gingivalis lipopolysacch aride mediates interleukin-6 and interleukin-8 mRNA/protein expression in pulpal inflammation

BACKGROUND/PURPOSE

The signaling mechanisms for Porphyromonas gingivalis lipopolysaccharide (PgLPS)-induced inflammation in human dental pulp cells are not fully clarified. This in vitro study aimed to evaluate the involvement of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in PgLPS-induced pulpal inflammation.

METHODS

Human dental pulp cells (HDPCs) were challenged with PgLPS with or without pretreatment and coincubation with a PI3K/Akt inhibitor (LY294002). The gene or protein levels of PI3K, Akt, interleukin (IL)-6, IL-8, alkaline phosphatase (ALP), osteocalcin and osteonectin were analyzed by reverse transcription polymerase chain reaction (PCR), real-time PCR, western blotting, and immunofluorescent staining. In addition, an enzyme-linked immunosorbent assay was used to analyze IL-6 and IL-8 levels in culture medium.

RESULTS

In response to 5 μg/ml PgLPS, IL-6, IL-8, and PI3K, but not Akt mRNA expression of HDPCs, was upregulated. IL-6, IL-8, PI3K, and p-Akt protein levels were stimulated by 10-50 μg/ml of PgLPS in HDPCs. PgLPS also induced IL-6 and IL-8 secretion at concentrations higher than 5 μg/ml. Pretreatment and co-incubation by LY294002 attenuated PgLPS-induced IL-6 and IL-8 mRNA expression in HDPCs. The mRNA expression of ALP, but not osteocalcin and osteonectin, was inhibited by higher concentrations of PgLPS in HDPCs.

CONCLUSION

P. gingivalis contributes to pulpal inflammation in HDPCs by dysregulating PI3K/Akt signaling pathway to stimulate IL-6 and IL-8 mRNA/protein expression and secretion. These results are useful for understanding the pulpal inflammation and possible biomarkers of inflamed pulp diagnosis and treatment.

MicroRNA expression in apical periodontitis and pulpal inflammation: a systematic review

Background

The aim of this systematic review is to determine microRNAs (miRs) that are differently expressed between diseased pulpal and periapical tissues.

Design

This systematic review used PubMed, Scopus, EBSCO, ProQuest, Cochrane database as well as manual searching to extract studies from January 2012 up to February 2022.

Results

A total of 12 studies met the eligibility criteria were included. All selected studies were of case-control type. Twenty-four miRNAs associated with apical periodontitis, 11 were found to be upregulatedand 13 were downregulated. Four out of the 44 miRs associated with pulpal inflammation were upregulated, whereas forty were downregulated. Six miRs, namely hsa-miR-181b, hsa-miR-181c,hsa-miR-455-3p,hsa-miR-128-3p, hsa-miR199a-5p, and hsa-miR-95, exhibited considerable downregulation in both periapical and pulp tissues.

Conclusion

MiRs have been investigated for their role in pulpal and periapical biology and may be utilised in diagnostic and therapeutic purposes. Further investigations are required to determine why certain irreversible pulpitis situations progress to apical periodontitis and others do not, based on the various miR expressions. Moreover, clinical and laboratory trials are needed to support this theory.

Influence of Direct Pulp Capping with Calcium Hydroxide and Mineral Trioxide Aggregate on Systemic Oxidative Stress in Rats

Direct pulp capping is a procedure where materials are placed on exposed vital pulp tissue in order to stimulate reparative dentinogenesis and preserve pulp vitality. Carious pulp exposure and direct pulp capping are usually accompanied by pulp inflammation which can affect pro- and anti-oxidative systems locally or systemically. Therefore, this study aimed to investigate the potential influence of direct capping of inflamed rat dental pulp with calcium hydroxide (CH) and mineral trioxide aggregate (MTA) on parameters of systemic oxidative status.

Dental pulps of the first maxillary molars of Albino rats (n=32) were exposed and capped with either CH (n=8), MTA (n=8) or were left untreated (n=8). Animals with healthy pulp were used as a healthy control (n=8). After four weeks, animals were euthanized and blood samples were collected for biochemical analysis of parameters of systemic oxidative stress by spectrophotometric method.

Untreated control had the significantly higher (p <0.05) values of pro-oxidative parameters and lower (p <0.05) values of anti-oxidative parameters (superoxide dismutase and reduced glutathione) compared to healthy control. CH and MTA groups showed reduced values of pro-oxidative parameters compared to untreated control and values of anti-oxidative parameters comparable to healthy control.

Pulp exposure led to disbalance in systemic oxidative parameters while direct pulp capping with calcium hydroxide and mineral trioxide aggregate restored the levels of systemic oxidative parameters to that of animals with healthy dental pulp. These results indicate the importance of direct pulp capping and the potential influence of untreated inflamed pulp on systemic health.

Modified pulpotomy procedure in immature permanent teeth with apical periodontitis: a randomised controlled trial

OBJECTIVES

The objective of this study was to evaluate the effectiveness of a modified pulpotomy (MP) procedure in immature permanent teeth with apical periodontitis (AP).

DESIGN

Randomised controlled trial.

SETTING

One public hospital in Shanghai, China PARTICIPANTS: A total of 33 teeth (31 patients) with a definitive diagnosis of AP with radiographic periapical radiolucency were recruited in this study. All the patients (teeth) completed the study accordingly.

METHODS AND INTERVENTION

Patients were randomly assigned to either MP or apexification treatment groups and were followed up for 12 months. Clinical symptoms and complications were recorded, and parallel periapical radiographic images were used to measure changes in root length and apical diameter. Wilcoxon's rank sum test and Fisher's exact test were used to compare the clinical and radiographic outcomes between MP and apexification, and analysed with analysis of variance.

MAIN OUTCOME MEASURE

The primary outcome was increase in root length at 12 months. The secondary outcomes included tooth survival, clinical success and decrease in apical diameter.

RESULTS

MP group showed a significant increase in root length (10.05%±2.14% vs 1.16%±0.79%, p<0.05) at 12 months and a decrease in apical diameter (48.88%±10.42% vs 15.90%±8.88%, p<0.05) as compared with the apexification group. The tooth survival rate was 100%, and 90.91% (30/33) of teeth were asymptomatic with apical healing in both treatment groups (p>0.05).

CONCLUSIONS

MP can be an option for treating immature permanent teeth with AP. MP showed better performance in terms of continued root maturation than apexification. MP and apexification achieved comparable outcomes with regard to the resolution of clinical symptoms and apical healing.

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17012169.

Anti-Inflammatory and Mineralization Effects of an ASP/PLGA-ASP/ACP/PLLA-PLGA Composite Membrane as a Dental Pulp Capping Agent

Dental pulp is essential for the development and long-term preservation of teeth. Dental trauma and caries often lead to pulp inflammation. Vital pulp therapy using dental pulp-capping materials is an approach to preserving the vitality of injured dental pulp. Most pulp-capping materials used in clinics have good biocompatibility to promote mineralization, but their anti-inflammatory effect is weak. Therefore, the failure rate will increase when dental pulp inflammation is severe. The present study developed an amorphous calcium phosphate/poly (L-lactic acid)-poly (lactic-co-glycolic acid) membrane compounded with aspirin (hereafter known as ASP/PLGA-ASP/ACP/PLLA-PLGA). The composite membrane, used as a pulp-capping material, effectively achieved the rapid release of high concentrations of the anti-inflammatory drug aspirin during the early stages as well as the long-term release of low concentrations of aspirin and calcium/phosphorus ions during the later stages, which could repair inflamed dental pulp and promote mineralization. Meanwhile, the composite membrane promoted the proliferation of inflamed dental pulp stem cells, downregulated the expression of inflammatory markers, upregulated the expression of mineralization-related markers, and induced the formation of stronger reparative dentin in the rat pulpitis model. These findings indicate that this material may be suitable for use as a pulp-capping material in clinical applications.

TAS2R supports odontoblastic differentiation of human dental pulp stem cells in the inflammatory microenvironment

Background

Inflammatory microenvironment promotes odontoblastic differentiation in human dental pulp stem cells (hDPSCs), but the regulatory mechanisms remain unclear. In this study, we aimed to explore the role of TAS2R in odontoblastic differentiation of hDPSCs in the inflammatory microenvironment.

Methods

Microarray analysis was performed to explore the differential mRNA profiles in inflammatory and healthy pulp tissues from the patients. hDPSCs isolated from the healthy pulp tissues were stimulated by LPS, TNFα and IL-6, respectively, to verify the effect of TAS2R. The expression markers related to odontoblastic differentiation of hDPSCs were observed by qPCR and chemical staining methods. TAS2R10 was overexpressed or silenced to observe the effect on odontoblastic differentiation of hDPSCs under LPS stimulation. The G protein and intracellular Ca²⁺ were detected, respectively, by qPCR and Fluo-4AM Ca²⁺ fluorescent probe.

Results

The expression of TAS2R was significantly upregulated in the inflammatory pulp tissues. In vitro, 5 subtypes of TAS2R mRNA expressions including TAS2R10, TAS2R14, TAS2R19, TAS2R30 and TAS2R31 in hDPSCs increased under the stimulation of LPS, TNFα or IL-6. In odontoblastic differentiation medium, we found LPS, TNFα or IL-6 stimulation promoted odontoblastic differentiation of hDPSCs. TAS2R10 overexpression in hDPSCs significantly increased the expression markers related to odontoblastic differentiation, whereas TAS2R10 silencing revealed the opposite effect. Furthermore, G protein was activated, and at the same time, intracellular Ca²⁺ enhanced when TAS2R10 was overexpressed, but decreased when TAS2R10 was silenced.

Conclusions

This study demonstrated that TAS2R was found to be expressed in hDPSCs, and TAS2R promoted odontoblastic differentiation of hDPSCs by mediating the increase in intracellular Ca²⁺ via the G protein-coupled receptors (GPCR) conventional signaling pathway in inflammatory microenvironment, which may be a potential target for the development of effective conservative treatments for dental pulp repair.

Vital Pulp Therapy of Permanent Teeth with Reversible or Irreversible Pulpitis: An Overview of the Literature

Vital pulp therapy (VPT) has been recently proposed as an alternative approach even in symptomatic mature permanent teeth with deep caries’ lesions, aiming to maintain the pulp vitality over time and/or to avoid non-surgical root canal therapy (NSRCT). However, to date, the diagnosis of reversible or irreversible pulpitis is only based on clinical pain quantity and quality, without precisely reflecting the pulp inflammation status. Therefore, the aim of the present study was to provide an overview based on the current scientific literature to demonstrate the clinical effectiveness of VPT on mature permanent teeth, validating the use of hydraulic calcium silicate-based cements and their role in pain management. VPT may be successfully applied not only in mature permanent teeth diagnosed with reversible pulpitis, but also in permanent dental elements with signs and symptoms of irreversible pulpitis. Hydraulic cements showed favorable outcomes in terms of decrease of pro-inflammatory mediators and of post-operative pain. Pain plays a central role in the chance to perform VPT in mature permanent teeth, since it may be considered as a pre-operative diagnostic criterion as well as a treatment success parameter. In addition, proper assessment of pulp inflammation and choice of appropriate materials are key factors in enhancing VPT success.

Identification of Immune-Related lncRNA Regulatory Network in Pulpitis

Background. Long noncoding RNAs (lncRNAs) are emerging as critical regulators of various biological processes, including immune regulation. Methods. Due to the critical significance of immunological responses in the development and progression of pulpitis, we used an integrated algorithm to identify immune-related lncRNAs and then examined the lncRNA-immunity regulation network in pulpitis. Before identifying immune-related lncRNAs, the data from GEO datasets were precleaned. ConsensusClusterPlus was used to differentiate immune-related pulpitis subgroups. Enrichment analysis using GO and MSigDB databases was employed to determine the differences in molecular function, cellular component, and biological process between the two pulpitis subtypes. Results. An integrated algorithm was designed to filtrate immune-related lncRNAs accurately. 790 immune-related lncRNAs were found in 17 immunological categories, with 38 of them perturbated in pulpitis. The Cytoscape software was used to visualize the relationship between representative immune regulatory pathways and immune-related lncRNAs. Two immune-related pulpitis subtypes were discovered using differentially expressed immune-related lncRNAs. Subtype 2 has a stronger association with immune-related pathways than subtype 1 does. Conclusions. Our study identified many immune-related lncRNAs and investigated potential lncRNA regulation networks; meanwhile, the molecular subtypes of pulpitis were identified, all of which will be relevant for further research into inflammatory and immunological processes in pulpitis.

Influence of HEMA on LPS- and LTA-stimulated IL-6 release from human dental pulp cells

OBJECTIVE

Dental pulp cells interact with immunogenic components such as LPS (lipopolysaccharide) or LTA (lipoteichoic acid) released from microorganisms in carious lesions. In the present investigation, the formation of the pro-inflammatory cytokines TNFα and IL-6 in LPS- or LTA-stimulated cells from the dental pulp interface and pulp fibroblasts was analyzed in the presence of the resin monomer 2-hydroxyethyl methacrylate (HEMA) under varying cellular redox conditions.

METHOD

Human pulp fibroblasts (HPC) or cells from the dental pulp interface expressing an odontoblast phenotype (hOD-1) were exposed to LTA, LPS or HEMA for 1 h or 24 h. Redox homeostasis was modified by the prooxidant BSO (L-buthionine sulfoximine) or the antioxidant NAC (N-acetyl cysteine). Formation of TNFα or IL-6 was analyzed by ELISA, and cell survival was determined by a crystal violet assay. Statistical analyses were performed using the Mann-Whitney-U-test.

RESULTS

Secretion of TNFα was not detected in LPS- or LTA-stimulated HPC or hOD-1, and IL-6 was not found after a short exposure (1 h). After a 24 h exposure, LPS induced a 3-fold increase in IL-6 formation in HPC, while LTA stimulated IL-6 release about 20-fold. Likewise, LTA was more effective than LPS in hOD-1 stimulating IL-6 levels about 50-fold. HEMA inhibited the LPS- and LTA-induced IL-6 release, and this effect was enhanced by BSO but counteracted by NAC in both cell types. IL-6 release was independent of cell survival rates.

CONCLUSIONS

The protective immune response in odontoblasts and pulp fibroblasts is impaired by monomers such as HEMA through the disturbance of the redox homeostasis.

Short-Term Pain Evolution and Treatment Success of Pulpotomy as Irreversible Pulpitis Permanent Treatment: A Non-Randomized Clinical Study

The objective of this work was to evaluate (1) the short-term evolution of pain and (2) the treatment success of full pulpotomy as permanent treatment of irreversible pulpitis in mature molars. The study consisted of a non-randomized comparison between a test group (n = 44)—full pulpotomy performed by non-specialist junior practitioners, and a control group (n = 40)—root canal treatments performed by specialized endodontists. Short-term pain score (Heft–Parker scale) was recorded pre-operatively, then at 24 h and 7 days post-operatively. Three outcomes were considered for treatment success: radiographic, clinical and global success. For short-term evolution of pain, a non-parametric Wilcoxon test was performed (significance level = 0.05). For treatment success, a Pearson Chi square or Fisher test were performed (significance level = 0.017–Bonferroni correction). There was no significant difference between test and control groups neither regarding short term evolution of pain at each time point, nor regarding clinical (80% and 90%, respectively) or global success (77% and 67%, respectively). However, a significant difference in radiographic success was observed (94% and 69%, respectively). The present work adds to the existing literature to support that pulpotomy as permanent treatment could be considered as an acceptable and conservative treatment option, potentially applied by a larger population of dentists.

Assessment of Mineralization, Oxidative Stress, and Inflammation Mechanisms in the Pulp of Primary Teeth

Inflammation in primary teeth (PT) is commonly associated with a lower sensibility to painful stimuli, compared to permanent teeth, and usually leads to late presentation for dental treatment. Data obtained on the molecular assessments of dental pulp and clinical examinations could guide practitioners to conduct precise diagnoses and correct treatments. The aim of our pilot study was to assess the levels of several biomarkers (e.g., mineralization, oxidative stress, and inflammation) in primary teeth. The research included 46 dental pulp specimens collected from the primary teeth of children and adolescents between the ages of 6 and 12. The experimental groups consisted of 18 samples collected from primary teeth with acute pulpitis and 15 samples from chronically inflamed pulp tissues. The control group was represented by 13 specimens acquired from clinically healthy primary teeth. The enzyme-linked immunosorbent assay (ELISA) technique was used to determine the protein expression of tumor necrosis factor-α (TNF-α), superoxide dismutase-3 (SOD-3), osteocalcin, and transforming growth factor-β1 (TGF-β1) in the lysates. Our results revealed that all of the studied parameters presented statistically significant (p ≤ 0.05) increased levels in both experimental groups compared to the control samples. Furthermore, osteocalcin presented statistically significant increased concentrations in chronically- versus acute-inflamed pulp samples (p ≤ 0.05). The studied molecules may have an influential role in acute and chronic pulp inflammation in primary teeth.

A critical analysis of research methods and experimental models to study pulpitis

Pulpitis is the inflammatory response of the dental pulp to a tooth insult, whether it is microbial, chemical, or physical in origin. It is traditionally referred to as reversible or irreversible, a classification for therapeutic purposes that determines the capability of the pulp to heal. Recently, new knowledge about dental pulp physiopathology led to orientate therapeutics towards more frequent preservation of pulp vitality. However, full adoption of these vital pulp therapies by dental practitioners will be achieved only following better understanding of cell and tissue mechanisms involved in pulpitis. The current narrative review aimed to discuss the contribution of the most significant experimental models developed to study pulpitis. Traditionally, in vitro two(2D)- or three(3D)-dimensional cell cultures or in vivo animal models were used to analyse the pulp response to pulpitis inducers at cell, tissue or organ level. In vitro 2D cell cultures were mainly used to decipher the specific roles of key actors of pulp inflammation such as bacterial by-products, pro-inflammatory cytokines, odontoblasts or pulp stem cells. However, these simple models did not reproduce the 3D organisation of the pulp tissue and, with rare exceptions, did not consider interactions between resident cell types. In vitro tissue/organ-based models were developed to better reflect the complexity of the pulp structure. Their major disadvantage is that they did not allow the analysis of blood supply and innervation participation. On the contrary, in vivo models have allowed researchers to identify key immune, vascular and nervous actors of pulpitis and to understand their function and interplay in the inflamed pulp. However, inflammation was mainly induced by iatrogenic dentine drilling associated with simple pulp exposure to the oral environment or stimulation by individual bacterial by-products for short periods. Clearly, these models did not reflect the long and progressive development of dental caries. Lastly, the substantial diversity of the existing models makes experimental data extrapolation to the clinical situation complicated. Therefore, improvement in the design and standardization of future models, for example by using novel molecular biomarkers, databased models and artificial intelligence, will be an essential step in building an incremental knowledge of pulpitis in the future.

Comparison of ADAMTS Levels in Pulp Tissue Samples of Healthy and Symptomatic Irreversible Pulpitis Teeth

AIM

The aim of this study was to compare the levels of different ADAMTS (-1,-4, and -9) related to the breakdown of the proteoglycans and TIMP-3 levels that inhibit ADAMTS in the extra cellular matrix (ECM) of healthy pulp and symptomatic irreversible pulpitis.

METHODS

Pulp tissue samples diagnosed with healthy and symptomatic irreversible pulpitis were collected from 48 participants. Healthy and inflamed pulps were directly transferred to Eppendorf® tubes and stored at -80 °C (Nüve-DF490, Ankara, Türkiye) until further use. Routine root canal treatment procedures for the teeth were performed, after which the treatment process was completed. The levels of ADAMTS-1, ADAMTS-4, ADAMTS-9, and TIMP-3 were measured in supernatants of human dental pulp tissue extracts using ELISA kits (USCN, Wuhan, China). Independent sample t test and one-way analysis of variance (ANOVA) were used for parametric data, Kruskal-Wallis and Mann-Whitney U tests were used for non-parametric data.

RESULTS

There was a statistically significant difference between ADAMTS-1, ADAMTS-9 and TIMP-3 levels of the healthy pulp and pulpitis groups (p < 0.05), but there was no significant difference for ADAMTS-4 levels (p ˃ 0.05). It was found that the levels of ADAMTS-1 and ADAMTS-9 were higher in the pulpitis group compared to the healthy pulp group, while the TIMP-3 level decreased (p < 0.05).

CONCLUSION

As a result of this study, it was concluded that ADAMTS-1, ADAMTS-9 and TIMP-3 might have a role in pulpal inflammation, while ADAMTS-4 was not related to pulpal inflammation.

Fibroblast membrane-camouflaged nanoparticles for inflammation treatment in the early stage

Unrestrained inflammation is harmful to tissue repair and regeneration. Immune cell membrane-camouflaged nanoparticles have been proven to show promise as inflammation targets and multitargeted inflammation controls in the treatment of severe inflammation. Prevention and early intervention of inflammation can reduce the risk of irreversible tissue damage and loss of function, but no cell membrane-camouflaged nanotechnology has been reported to achieve stage-specific treatment in these conditions. In this study, we investigated the prophylactic and therapeutic efficacy of fibroblast membrane-camouflaged nanoparticles for topical treatment of early inflammation (early pulpitis as the model) with the help of in-depth bioinformatics and molecular biology investigations in vitro and in vivo. Nanoparticles have been proven to act as sentinels to detect and competitively neutralize invasive Escherichia coli lipopolysaccharide (E. coli LPS) with resident fibroblasts to effectively inhibit the activation of intricate signaling pathways. Moreover, nanoparticles can alleviate the secretion of multiple inflammatory cytokines to achieve multitargeted anti-inflammatory effects, attenuating inflammatory conditions in the early stage. Our work verified the feasibility of fibroblast membrane-camouflaged nanoparticles for inflammation treatment in the early stage, which widens the potential cell types for inflammation regulation.

Identification of Pulpitis-Related Potential Biomarkers Using Bioinformatics Approach

Inflammatory reaction of pulp tissue plays a role in the pathogen elimination and tissue repair. The evaluation of severity of pulpitis can serve an instructive function in therapeutic scheme. However, there are many limitations in the traditional evaluation methods for the severity of pulpitis. Based on the Gene Expression Omnibus (GEO) database, our study discovered 843 differentially expressed genes (DEGs) related to pulpitis. Afterwards, we constructed a protein-protein interaction (PPI) network of DEGs and used MCODE plugin to determine the key functional subset. Meanwhile, genes in the key functional subset were subjected to GO and KEGG enrichment analyses. The result showed that genes were mainly enriched in inflammatory reaction-related functions. Next, we screened out intersections of PPI network nodes and pulpitis-related genes. Then, 20 genes were obtained as seed genes. In the PPI network, 50 genes that had the highest correlation with seed genes were screened out using random walk with restart (RWR). Furthermore, 4 pulpitis-related hub genes were obtained from the intersection of the top 50 genes and genes in the key functional subset. Finally, GeneMANIA was utilized to predict genes coexpressed with hub genes, and expression levels of the 4 hub genes in normal and pulpitis groups were analyzed based on GEO data. The result demonstrated that the 4 hub genes were mainly coexpressed with chemokine-related genes and were remarkably upregulated in the pulpitis group. In short, we eventually determined 4 potential biomarkers of pulpitis.

Effect of Root Canal Therapy Combined with Full Crown Restoration on the Level of Inflammatory Factors and Chewing Function in Patients with Cracked Teeth and Chronic Pulpitis

Objective

To explore the clinical effect of root canal therapy combined with full crown restoration in patients with cracked teeth and chronic pulpitis.

Methods

From May 2018 to June 2020, 87 patients with cracked teeth and chronic pulpitis in our hospital were selected; the patients were randomly divided into the control group and the research group by random number method. The control group only used root canal therapy; the research group used root canal therapy combined with full crown restoration. The therapeutic effect, levels of inflammatory factors, chewing function, periodontal index, complications, and quality of life were compared between the two groups.

Results

The total effective rate of the research group (97.78%) was better than the total effective rate of the control group (85.71%) (P < 0.05). Compared with before treatment, the serum levels of interleukin-1β (IL-1β), IL-6, and C-reactive protein (CRP) of the two groups of patients decreased after treatment. After treatment, compared with the control group, the serum levels of IL-1β, IL-6, and CRP in the research group decreased (P < 0.05). Compared with before treatment, the bite force of teeth and chewing efficiency of the two groups of patients increased after treatment. After treatment, compared with the control group, the bite force of teeth and chewing efficiency of the research group increased (P < 0.05). Compared with before treatment, the plaque index (PLI), probing depth (PD), gingival sulcus bleeding index (BI), and gingival index (GI) of the two groups of patients decreased after treatment. After treatment, compared with the control group, the PLI, PD, BI, and GI of the research group decreased (P < 0.05). The total incidence of complications in the research group was (11.11%), and the total incidence of complications in the control group was (16.67%); there was no significant difference between the two groups (P > 0.05). After treatment, compared with the control group, the quality of life scores of the patients in the research group were reduced (P < 0.05).

Conclusion

Root canal therapy and full crown restoration have a definite curative effect in patients with cracked teeth and chronic pulpitis, which can improve the inflammatory response, restore chewing function, maintain periodontal health, improve the quality of life, and do not increase the incidence of complications, so it has good application value.

The Role of microRNAs in Pulp Inflammation

The dental pulp can be affected by thermal, physical, chemical, and bacterial phenomena that stimulate the inflammatory response. The pulp tissue produces an immunological, cellular, and vascular reaction in an attempt to defend itself and resolve the affected tissue. The expression of different microRNAs during pulp inflammation has been previously documented. MicroRNAs (miRNAs) are endogenous small molecules involved in the transcription of genes that regulate the immune system and the inflammatory response. They are present in cellular and physiological functions, as well as in the pathogenesis of human diseases, becoming potential biomarkers for diagnosis, prognosis, monitoring, and safety. Previous studies have evidenced the different roles played by miRNAs in proinflammatory, anti-inflammatory, and immunological phenomena in the dental pulp, highlighting specific key functions of pulp pathology. This systematized review aims to provide an understanding of the role of the different microRNAs detected in the pulp and their effects on the expression of the different target genes that are involved during pulp inflammation.

Effect of treatment with resiniferatoxin in an experimental model of pulpal inflammatory in mice

AIM

To evaluate whether treatment with resiniferatoxin (RTX) is capable of lowering the plasma levels of PGE₂ and TNF-α, as well as histopathological parameters in inflammation of pulp tissue in a mouse experimental model.

METHODOLOGY

Ten groups of six BALB/c mice were formed as follows: healthy group (H_C ), healthy group treated with RTX (H_RTX ), two groups with pulp inflammation at 14 and 18 hours (PI₁₄ /PI₁₈ ), six groups with pulpal inflammation plus treatment with Ibuprofen (IBU₁₄ /IBU₁₈ ), dexamethasone (DEX₁₄ /DEX₁₈ ) and resiniferatoxin (RTX₁₄ /RTX₁₈ ) at 14 and 18 hours, respectively. Pulpal inflammation was induced through occlusal exposure of the pulp of the maxillary first molar. The plasma levels of PGE₂ and TNF-α and the histological parameters of the pulp tissue of the H_C and H_RTX groups were evaluated at the time of acquiring the animals. In the other groups, the plasma levels of PGE₂ and TNF-α and the histopathological parameters were evaluated at 14 and 18 hours after pulp damage. Plasma levels of PGE₂ and TNF-α were quantified by ELISA, and the histopathological parameters were evaluated by H/E staining. Statistical significance was determined by one-way analysis of variance (ANOVA) to test for overall differences between group means.

RESULTS

A significant increase (*p < .05) in plasma levels of PGE₂ and TNF-α occurred 14 and 18 hours after pulp damage. In addition, treatment with RTX significantly decreased (*p < .05) the plasma levels of PGE₂ and TNF-α at 14 and 18 hours after pulp damage, as well as the infiltrate of inflammatory cells at 18 hours after pulp damage, similarly to treatment with ibuprofen and dexamethasone.

CONCLUSION

It was possible to detect systemic levels of PGE₂ and TNF-α at 14 and 18 hours after pulp damage. Likewise, treatment with RTX was associated with an anti-inflammatory effect similar to treatment with ibuprofen and dexamethasone. These findings place resiniferatoxin as a therapeutic alternative in the treatment of inflammatory diseases in Dentistry.

Comprehensive Analysis of Differentially Expressed Genes in Clinically Diagnosed Irreversible Pulpitis by Multiplatform Data Integration Using a Robust Rank Aggregation Approach

INTRODUCTION

Molecular diagnosis may overcome the limitations of clinical and histologic diagnosis in pulpitis, thereby benefiting many treatment techniques, such as vital pulp therapies. In this study, integrated microarray data on pulpitis were used to obtain a list of normalized differentially expressed (DE) genes for analyzing the molecular mechanisms underlying pulpitis and identifying potential diagnostic biomarkers.

METHODS

A systematic search of public microarray and sequencing databases was performed to obtain expression data of pulpitis. Robust rank aggregation (RRA) was used to obtain DE gene lists (RRA_DEmRNAs and RRA_DElncRNAs) between inflamed pulp and normal samples. DE genes were evaluated by functional enrichment analyses, correlation analyses for inflammation-related RRA_DEmRNAs, and protein-protein interaction and competing endogenous RNA network construction. Quantitative real-time polymerase chain reaction validation was applied in snap-frozen pulp tissues.

RESULTS

Using the GSE77459 and GSE92681 data sets, 280 RRA_DEmRNAs and 90 RRA_DElncRNAs were identified. RRA_DEmRNAs were significantly enriched in inflammation-related biological processes and osteoclast differentiation and tumor necrosis factor, chemokine, and B-cell receptor signaling pathways. The molecular complex detection and cytoHubba methods identified 2 clusters and 10 hub genes in the protein-protein interaction network. The competing endogenous RNA network was composed of 2 long noncoding RNAs (ADAMTS9-AS2 and LINC00290), 2 microRNAs (hsa-miR-30a-5p and hsa-miR-128-3p), and 3 messenger RNAs (ABCA1, FBLN5, and SOCS3). The expression between most top inflammation-related RRA_DEmRNAs in pulpitis showed positive correlations. Quantitative real-time polymerase chain reacation validated the expression trends of selected genes, including ITGAX, TREM1, CD86, FCGR2A, ADAMTS9-AS2, LINC00290, hsa-miR-30a-5p, hsa-miR-128-3p, RASGRP3, IL3RA, CCDC178, CRISPLD1, LINC01857, AC007991.2, ARHGEF26-AS1, and AL021408.1.

CONCLUSIONS

The identified biomarkers provide insight into the pathology and may aid in the molecular diagnosis of pulpitis.

ILs and MMPs Levels in Inflamed Human Dental Pulp: A Systematic Review

A wide range of mediators are released from the pulp tissue because of bacterial invasion which causes inflammation. Interleukins (ILs) and matrix metalloproteinases (MMPs) have a leading role in initiating and spreading of inflammation because of their synergic action. Biomarkers such as ILs and MMPs can be identified via several methods, establishing the inflammatory response of the dental pulp. The aim of this systematic review is to evaluate the levels of ILs and/or MMPs in human dental pulp. PubMed, OVID, Cochrane, Scopus, Web of Science and Wiley online library databases were searched for original clinical studies. After applying inclusion and exclusion criteria, a quality assessment of studies was performed based on a modified Newcastle-Ottawa scale. In the review were included articles that evaluated the presence of ILs and/or MMPs in pulp tissue using enzyme-linked immunosorbent assay (ELISA) or western blot or multiplex assay. Six articles were included in the present synthesis. Although various diagnostic methods were used, statistically significant higher levels of ILs and/or MMPs were mostly found in the experimental groups compared to healthy pulp samples. The biomarkers studied can be a promising tool to evaluate pulp tissue health or even in pulpitis treatment.

Identification and validation of novel biomarkers and therapeutics for pulpitis using connectivity mapping

AIM

To create an irreversible pulpitis gene signature from microarray data of healthy and inflamed dental pulps, followed by a bioinformatics approach using connectivity mapping to identify therapeutic compounds that could potentially treat pulpitis.

METHODOLOGY

The Gene Expression Omnibus (GEO) database, an international public repository of genomics data sets, was searched for human microarray datasets assessing pulpitis. An irreversible pulpitis gene expression signature was generated by differential expression analysis. The statistically significant connectivity map (ssCMap) method was used to identify compounds with a highly correlating gene expression pattern. qPCR was used to validate novel pulpitis genes. An ex vivo pulpitis model was used to test the effects of the compounds identified, and the level of inflammatory cytokines was measured with qPCR, ELISA and multiplex array. Means were compared using the t-test or ANOVA with the level of significance set at p ≤ .05.

RESULTS

Pulpitis gene signatures were created using differential gene expression analysis at cutoff points p = .0001 and .000018. Top upregulated genes were selected as potential pulpitis biomarkers. Among these, IL8, IL6 and MMP9 were previously identified as pulpitis biomarkers. Novel upregulated genes, chemokine (C-C motif) ligand 21 (CCL21), metallothionein 1H (MT1H) and aquaporin 9 (AQP9) were validated in the pulp tissue of teeth clinically diagnosed with irreversible pulpitis using qPCR. ssCMap analysis identified fluvastatin (Statin) and dequalinium chloride (Quaternary ammonium) as compounds with the strongest correlation to the gene signatures (p = .0001). Fluvastatin reduced IL8, IL6, CCL21, AQP9 (p < .001) and MMP9 (p < .05) in the ex vivo pulpitis model, while dequalinium chloride reduced AQP9 (p < .001) but had no significant effect on the other biomarkers.

CONCLUSIONS

AQP9, MT1H and CCL21 were identified and validated as novel biomarkers for pulpitis. Fluvastatin and dequalinium chloride identified by the ssCMap as potential therapeutics for pulpitis reduced selected pulpitis biomarkers in an ex vivo pulpitis model. In vivo testing of these licenced drugs is warranted.

Enhanced Neurokinin-1 Receptor Expression Is Associated with Human Dental Pulp Inflammation and Pain Severity

Substance P (SP) is a peptide involved in many biological processes, including nociception and inflammation. SP has a high affinity for its receptor neurokinin-1 (NK-1R). SP/NK-1R complex plays a major role in the interactions going on during the onset of dental pain and inflammation. Objective. To identify the expression of NK-1R in healthy and inflamed human dental pulp, as well as to identify any association with severity of dental pain. Methods. This case-control study included ten irreversibly inflamed samples of dental pulp, which were extirpated from patients presenting with chief complaint of dental pain due to caries. Ten healthy pulps, extirpated from those teeth which were indicated for extraction due to orthodontic reasons, were used as the control group. Visual analog scale (VAS) and modified McGill Pain Questionnaire were used to assess the characteristic and severity of pain. Immunohistochemical study was performed using monoclonal antibodies against NK-1R. Results. The results showed that the NK-1R was expressed intensely in patients with higher pain score. The mean pain score in cases was 7.0 ± 2.0. The healthy dental pulps had negative or mild NK-1R staining of +1 intensity. The NK-1R score in cases was 2.4 ± 0.516 and 0.2 ± 0.4216 in controls. There was significant difference in NK-1R score between both groups (p value <0.05). There was a strong positive correlation between the pain score and NK-1R expression score. As the pain increased, the NK-1R expression score was also increased (0.95^∗∗, p value 0.000). Conclusions. NK-1R is overexpressed in inflamed dental pulp. SP/NK-1R modulation may provide a novel approach for the treatment of pulpal inflammation and pain.