Role of connexin 43 in odontoblastic differentiation and structural maintenance in pulp damage repair

Electric field promoted odontogenic differentiation of stem cells from apical papilla by remodelling cytoskeleton

AIM

This study examined the impact of direct current electric fields (DCEFs) on the biological properties of stem cells derived from the apical papilla (SCAP) and further elucidated the underlying mechanisms involved in odontogenic differentiation induced by DCEFs stimulation.

METHODOLOGY

The measurement of endogenous currents in wounded dentine was achieved using a non-invasive vibrating probe system. Two-dimensional (2D) and three-dimensional (3D) systems were developed to apply DCEFs of varying strengths. The migration direction and trajectories of SCAP within DCEFs were analysed using time-lapse imaging. Cell proliferation was assessed through Hoechst staining and the CCK-8 assay. Changes in cell morphology, arrangement, and polarization were examined using fluorescence staining. The odontogenic differentiation of SCAP in vitro was assessed using quantitative polymerase chain reaction (qPCR), western blot analysis, alkaline phosphatase staining, and Alizarin Red S staining. In vivo evaluation was conducted through Haematoxylin and eosin staining, immunohistochemistry staining, and Sirius Red staining after transplantation experiments.

RESULTS

Injured dentine demonstrated a significantly increased outward current, and DCEFs facilitated the migration of SCAP towards the anode. DCEFs at a magnitude of 100 mV/mm promoted SCAP proliferation, whereas DCEFs at 200 mV/mm enhanced both polarization and odontogenic differentiation of SCAP. The application of cytoskeletal polymerization inhibitors mitigated the odontogenic differentiation induced by DCEFs. In vivo studies confirmed that DCEFs promoted the differentiation of SCAP into odontoblast-like cells in an orderly arrangement, as well as the formation of collagen fibres and dentine-like tissue.

CONCLUSIONS

DCEFs of varying intensities exhibited an enhanced capacity for migration, proliferation, odontogenic differentiation, and polarization in SCAP. These findings provide substantial insights for the advancement of innovative therapeutic strategies targeting the repair and regeneration of immature permanent teeth and dentine damage.

Piezo Channels in Dentistry: Decoding the Functional Effects of Forces

The oral system is a highly complex mechanosensory structure that continuously adapts to changes in mechanical stimuli, exerting mechanical forces on cells and tissues. Understanding how these forces are converted into biochemical signals and how they mediate gene expression and cellular activities has been a significant focus in dentistry. Piezo channels, including Piezo1 and Piezo2, are mechanically activated cation channels characterized by an extracellular "cap" domain and 3 peripheral mechanosensitive blades. Recent research has demonstrated that mechanical forces applied to tissues can induce deformation of cell membranes, leading to conformational changes in Piezo channels that facilitate cation influx, thereby regulating cellular activities. The influx of Ca2+, the most discussed outcome of Piezo channel activation, initiates diverse signaling pathways that regulate dentin hypersensitivity, alveolar bone remodeling, and temporomandibular joint (TMJ) osteoarthritis. The chemical inhibition of Piezo channels has been shown to alleviate dentinal hypersensitivity, reduce the rate of orthodontic tooth movement, and slow the progression of TMJ osteoarthritis in rat models. Mice deficient in piezo channels exhibit impaired reactive dentin formation, reduced alveolar bone volume, and developmental deformities of the jawbone. Considering their roles in decoding the functional effects of mechanical forces, this review summarizes the involvement of Piezo channels in dentistry, organized by anatomical sites, to provide comprehensive knowledge of Piezo channels and their mediated signal crosstalk, which offers promising therapeutic prospects for the treatment of various force-related oral diseases.

Biomarkers in orofacial pain conditions: A narrative review

Orofacial pain conditions, including temporomandibular disorder, migraine, dental pain, and trigeminal neuralgia, are complex, multifactorial disorders with significant impacts on patients' quality of life. As understanding of the pathophysiology of these conditions has deepened, the role of molecular and genetic biomarkers in diagnosing, monitoring, and potentially treating orofacial pain has garnered increasing interest. This scoping review provides a comprehensive overview of the current state of research on biomarkers associated with orofacial pain conditions. By analyzing existing literature, we identify key biomarkers linked to inflammation, neural activity, and tissue degradation that are common across multiple conditions, as well as those specific to particular disorders. Our findings underscore the potential of these biomarkers to guide the development of personalized therapeutic strategies. However, the review also highlights the challenges faced by current biomarker research, including heterogeneity in study designs, small sample sizes, and a lack of longitudinal data. Addressing these challenges is critical for translating biomarker research into clinical practice and improving outcomes for patients with orofacial pain.

Bio-inspiration unveiled: Dissecting nature's designs through the lens of the female locust's oviposition mechanism

Investigating nature's ingenious designs and systems has become a cornerstone of innovation, influencing fields from robotics, biomechanics, and physics to material sciences. Two key questions, however, regarding bio-inspired innovation are those of how and where does one find bio-inspiration? The perspective presented here is aimed at providing insights into the evolving landscape of bio-inspiration discovery. We present the unique case of the female locust's oviposition as a valuable example for researchers and engineers seeking to pursue multifaceted research, encompassing diverse aspects of biological and bio-inspired systems. The female locust lays her eggs underground to protect them and provide them with optimal conditions for survival and hatching. To this end, she uses a dedicated apparatus comprising two pairs of special digging valves to propagate underground, while remarkably extending her abdomen by 2- to 3-fold its original length. The unique digging mechanism, the subterranean steering ability, and the extreme elongation of the abdomen, including the reversible extension of the abdominal central nervous system, all spark a variety of questions regarding materials, morphology, mechanisms, and their interactions in this complex biological system. We present the cross-discipline efforts to elucidate these fascinating questions, and provide future directions for developing bio-inspired technological innovations based on this remarkable biological system.

Peroxisomal dysfunction interferes with odontogenesis and leads to developmentally delayed teeth and defects in distinct dental cells in Pex11b-deficient mice

Human peroxisomal biogenesis disorders of the Zellweger syndrome spectrum affect skeletal development and induce tooth malformations. Whereas several peroxisomal knockout mouse studies elucidated the pathogenesis of skeletal defects, little information is available on how dental pathologies arise in peroxisomal biogenesis disorder patients. To understand the impact of severe peroxisomal dysfunction on early odontogenesis, here we performed morphometric studies on developing molars of new-born Pex11b knockout mice. Immunofluorescence analysis revealed reduced peroxisome number and mistargeting of the peroxisomal matrix enzyme catalase to the cytoplasm in several dental cell types of the Pex11b knockout animals. We also observed secondary mitochondrial alterations, comprising decreased staining of mitochondrial superoxide dismutase and of complex IV in cells of the developing molar. The peroxisomal defect caused by the PEX11b knockout also decreased the staining of cytokeratin intermediate filaments and of the secretory proteins amelogenin, osteopontin and osteocalcin. Interestingly, the staining of the gap junction protein connexin 43, an important modulator of tissue development, was also decreased, possibly causing the observed cellular disarrangement within the inner enamel epithelium and the odontoblast palisade. Taken together, our results show that the severe phenotype associated with the PEX11b knockout results in a reduction of the number of peroxisomes in dental cells and causes a delay odontogenesis. This adds a new component to the already described symptomatic spectrum induced by severe peroxisomal defects.

Blockade of connexin43-containing hemichannel attenuates the LPS-induced inflammatory response in human dental pulp cells by inhibiting the extracellular flux of ATP and HMGB1

Introduction

Tissue repair can be promoted by moderate inflammation but suppressed by excessive levels. Therefore, control of excessive inflammation following removal of infection plays a critical role in promotion of pulpal repair. Connexin 43 (Cx43) forms hemichannels (HCs) or gap channels (GJs) to facilitate the delivery of small molecules between cells to regulate both inflammation and repair. Understanding the role of Cx43 in dental pulp may help develop a potential strategy to attenuate the inflammation and promote the formation of reparative dentin in deep caries.

Methods

We firstly investigated the expression profile of Cx43 in infected human third molars by histological analysis; then, we detected channel activity of Cx43 and the effect of mediating release of small molecules in lipopolysaccharide (LPS)-induced inflammation in human dental pulp cells (hDPCs) by molecular biology methods. Results were analyzed by one-way ANOVA and the unpaired t-test. The level of significance was set at α = 0.05.

Results

Analysis showed that the expression of Cx43 was upregulated in human third molars as the degree of infection increased, and Cx43 was not only expressed in odontoblast layer, but also detected in cell-rich zone and pulp proper. LPS activated Cx43 HCs in hDPCs while inhibiting GJs; blockade of Cx43 HCs attenuated LPS-induced inflammation. Furthermore, LPS promoted the extracellular release of adenosine triphosphate (ATP) and high-mobility group box 1 (HMGB1) within hDPCs, thus exacerbating LPS-induced inflammation. The blockade of Cx43 HCs inhibited the extracellular release of ATP and HMGB1 within hDPCs.

Conclusion

Collectively, our finding suggested that Cx43 plays a key role in infection and inflammation in dental pulp. LPS activates Cx43 HCs to mediate the extracellular release of ATP and HMGB1 to exacerbate LPS-induced inflammation of hDPCs.

Depolarization induces calcium-dependent BMP4 release from mouse embryonic palate mesenchymal cells

Bone Morphogenetic Protein (BMP) signaling is essential for craniofacial development, though little is known about the mechanisms that govern BMP secretion. We show that depolarization induces calcium-dependent BMP4 release from mouse embryonic palate mesenchyme. We show endogenous transient changes in intracellular calcium occur in cranial neural crest cells, the cells from which embryonic palate mesenchyme derives. Waves of transient changes in intracellular calcium suggest that these cells are electrically coupled and may temporally coordinate BMP release. These transient changes in intracellular calcium persist in palate mesenchyme cells from embryonic day 9.5 to 13.5 mice. Disruption of a potassium channel called Kcnj2 significantly decreases the amplitude of calcium transients and the ability of cells to secrete BMP. Kcnj2 knockout mice have cleft palate and reduced BMP signaling. Our data suggest that temporal control of developmental cues is regulated by ion channels, depolarization, and intracellular calcium for mammalian craniofacial morphogenesis.

Connexin43 reduces LPS-induced inflammation in hDPCs through TLR4-NF-κB pathway via hemichannels

OBJECTIVES

Connexin43 (Cx43) is involved in the inflammation of many tissue types. Dental caries is infectious disease resulting from mineralized tissue dissolution by a specific bacterial population, causing pulp inflammation. However, Cx43's role in dental pulp remains unclear. Here, we investigated the function of Cx43 during pulp inflammation.

MATERIALS AND METHODS

We constructed a dentin injury model in Sprague-Dawley rats to investigate changes in Cx43 expression during pulp inflammation. Cx43 was inhibited in human dental pulp cells (hDPCs) that had been stimulated with lipopolysaccharide (LPS) to investigate the effect of Cx43 on inflammatory response. Promotion of TLR4-NF-κB pathway activity and special Cx43 channel inhibitors were used to clarify the function of Cx43 in hDPCs.

RESULTS

Dentin injury led to low-level inflammation in dental pulp. Following dentin injury, Cx43 expression initially decreased before gradually recovering to normal levels. Cx43 inhibition reduced LPS-induced expression of inflammatory cytokines and NF-κB pathway activity. Promotion of NF-κB pathway activity counteracted the effect of Cx43 in hDPCs. Furthermore, inhibition of Cx43 hemichannels reduced LPS-induced inflammatory cytokine expression.

CONCLUSIONS

Cx43 is involved in inflammation of dental pulp, while its inhibition reduced LPS-induced inflammation in hDPCs through NF-κB pathway via blockage of hemichannels.

Downregulation of connexin 43 is crucial for basal cell alignment in ameloblastoma and odontogenic keratocyst

Background

The current study aims at investigating gap junctions which allow cells to connect with one another. Such process is essential for cell differentiation and the preservation of diverse cell functions. It is noticeable that connexin 43 (Cnx43) was differentially expressed in ameloblasts and odontoblasts in the processes of odontogenesis. Moreover, in carcinoma in situ (CIS) and oral squamous cell carcinoma (SCC), Cnx43 expression apparently thought to be a defining feature of the neoplastic state of squamous epithelial cells. Aim: Therefore, the study has postulated that Cnx43 may be involved in the pathophysiology of ameloblastoma and certain odontogenic cysts whose epithelial constituents exhibit squamous cells.

Materials and methods

In order to prove the foregoing hypothesis, the study explored the immunohistochemical profiles of Cnx43 in ameloblastoma as well as some odontogenic cysts to assess Cnx43 trafficking and its relation with characteristic tissue architectures of odontogenic lesions. Results: The study has concluded that Cnx43 was down regulated significantly in follicular ameloblastoma with obvious ameloblasts-like cell components as well as in odontogenic keratocyst with palisaded basal cells. Additionally, other patterns of ameloblastoma (plexiform and desmoplastic) and different types of odontogenic cysts manifest heavy trafficking for Cnx43. Conclusion: Finally, altered Cnx43 expression between various patterns of ameloblastoma and odontogenic cysts might be related to their pathogenesis and is responsible for their morphological diversity.

Depolarization induces calcium-dependent BMP4 release from mouse embryonic palate mesenchyme

Ion channels are essential for proper morphogenesis of the craniofacial skeleton. However, the molecular mechanisms underlying this phenomenon are unknown. Loss of the Kcnj2 potassium channel disrupts Bone Morphogenetic Protein (BMP) signaling within the developing palate. BMP signaling is essential for the correct development of several skeletal structures, including the palate, though little is known about the mechanisms that govern BMP secretion. We introduce a tool to image the release of bone morphogenetic protein 4 (BMP4) from mammalian cells. Using this tool, we show that depolarization induces BMP4 release from mouse embryonic palate mesenchyme cells in a calcium-dependent manner. We show native transient changes in intracellular calcium occur in cranial neural crest cells, the cells from which embryonic palate mesenchyme derives. Waves of transient changes in intracellular calcium suggest that these cells are electrically coupled and may temporally coordinate BMP release. These transient changes in intracellular calcium persist in palate mesenchyme cells from embryonic day (E) 9.5 to 13.5 mice. Disruption of Kcnj2 significantly decreases the amplitude of calcium transients and the ability of cells to secrete BMP. Together, these data suggest that temporal control of developmental cues is regulated by ion channels, depolarization, and changes in intracellular calcium for mammalian craniofacial morphogenesis.

SUMMARY

We show that embryonic palate mesenchyme cells undergo transient changes in intracellular calcium. Depolarization of these cells induces BMP4 release suggesting that ion channels are a node in BMP4 signaling.

Role of YAP in Odontoblast Damage Repair in a Dentin Hypersensitivity Model

OBJECTIVES

The aim of this study was to investigate the molecular mechanism underlying odontoblast damage repair in dentin hypersensitivity (DH) and the role of Yes-associated protein (YAP) in this process.

METHODS

The DH model was constructed in Sprague-Dawley (SD) rats, and the in vivo expression of Piezo1, Integrin αvβ3, YAP, and dentin sialophosphoprotein (DSPP) was detected by immunohistochemistry. COMSOL Multiphysics software was used to simulate the dentinal tubule fluid flow velocity and corresponding fluid shear stress (FSS) on the odontoblast processes. MDPC-23 cells were cultured in vitro and loaded with a peristaltic pump for 1 hour at FSS values of 0.1, 0.3, 0.5, and 0.7 dyne/cm2. The expression of Piezo1, Integrin αvβ3, and YAP was detected by immunofluorescence. Verteporfin (a YAP-specific inhibitor) was utilised to confirm the effect of YAP on the expression of dentineogenesis-related protein under FSS.

RESULTS

The level and duration of external mechanical stimuli have an effect on the functional expression of odontoblasts. In DH, the harder the food that is chewed, the faster the flow of the dentinal tubule fluid and the greater the FSS on the odontoblast processes. The expression of Piezo1, Integrin αvβ3, and YAP can be promoted when the FSS is less than 0.3 dyne/cm2. After YAP inhibition, the DSPP protein expression level was reduced at 0.3 dyne/cm2 FSS.

CONCLUSIONS

These results suggest that appropriate FSS can enhance the expression of odontoblast-related factors in odontoblasts via the Piezo1-Integrin αvβ3-YAP mechanotransduction pathway and the YAP appears to play an essential role in the response of odontoblasts to external mechanical stimuli.

Epigenetic modulation of long noncoding RNA H19 in oral squamous cell carcinoma-A narrative review

Oral squamous cell carcinoma (OSCC) showed a seemingly increasing incidence in the last decade. In India, despite the use of tobacco decreased rapidly, in the past five years, the incidence pattern of OSCC over gender and age showed a drastic shift. About 51 % of the head and neck cancers are not associated with habits. Studies exploring various contributing factors in the incidence of this malignancy have documented. Recently, the epigenetic factors associated with the induction and progression of OSCC were explored. More than 90 % of the human genome is made up of non-coding transcriptome, which believed to be noises. However, these non-coding RNAs were identified to be the major epigenetic modulators, which raises concern over incidence of carcinoma in non-habit patients. H19 is a long non coding RNA which proved to be an effective biomarker in various carcinoma. Its role in oral squamous cell cancer was not investigated in depth. This review discusses in detail the various epigenetic role of H19 in inducing oral carcinogenesis.

Tooth agenesis patterns and variants in PAX9: A systematic review

Mutations in PAX9 are the most common genetic cause of tooth agenesis (TA). The aim of this study was to systematically review the profiles of the TA and PAX9 variants and establish their genotype-phenotype correlation. Forty articles were eligible for 178 patients and 61 mutations (26 in frame and 32 null mutations). PAX9 mutations predominantly affected molars, mostly the second molar, and the mandibular first premolar was the least affected. More missing teeth were found in the maxilla than the mandible, and with null mutations than in-frame mutations. The number of missing teeth was correlated with the locations of the in-frame mutations with the C-terminus mutations demonstrating the fewest missing teeth. The null mutation location did not influence the number of missing teeth. Null mutations in all locations predominantly affected molars. For the in-frame mutations, a missing second molar was commonly associated with mutations in the highly conserved paired DNA-binding domain, particularly the linking peptide (100% prevalence). In contrast, C-terminus mutations were rarely associated with missing second molars and anterior teeth, but were commonly related to an absent second premolar. These finding indicate that the mutation type and position contribute to different degrees of loss of PAX9 function that further differentially influences the manifestations of TA. This study provides novel information on the correlation of the PAX9 genotype-phenotype, aiding in the genetic counseling for TA.

Cyclic Stretching Triggers Cell Orientation and Extracellular Matrix Remodeling in a Periodontal Ligament 3D In Vitro Model

During orthodontic tooth movement (OTM), the periodontal ligament (PDL) plays a crucial role in regulating the tissue remodeling process. To decipher the cellular and molecular mechanisms underlying this process in vitro, suitable 3D models are needed that more closely approximate the situation in vivo. Here, a customized bioreactor is developed that allows dynamic loading of PDL-derived fibroblasts (PDLF). A collagen-based hydrogel mixture is optimized to maintain structural integrity and constant cell growth during stretching. Numerical simulations show a uniform stress distribution in the hydrogel construct under stretching. Compared to static conditions, controlled cyclic stretching results in directional alignment of collagen fibers and enhances proliferation and spreading ability of the embedded PDLF cells. Effective force transmission to the embedded cells is demonstrated by a more than threefold increase in Periostin protein expression. The cyclic stretch conditions also promote extensive remodeling of the extracellular matrix, as confirmed by increased glycosaminoglycan production. These results highlight the importance of dynamic loading over an extended period of time to determine the behavior of PDLF and to identify in vitro mechanobiological cues triggered during OTM-like stimulus. The introduced dynamic bioreactor is therefore a useful in vitro tool to study these mechanisms.

Near-infrared light-triggered nitric oxide nanocomposites for photodynamic/photothermal complementary therapy against periodontal biofilm in an animal model

Background: Periodontal disease, an oral disease that initiates with plaque biofilm infection, affects 10% of the global population. Due to the complexity of tooth root anatomy, biofilm resistance and antibiotic resistance, traditional mechanical debridement and antibiotic removal of biofilms are not ideal. Nitric oxide (NO) gas therapy and its multifunctional therapy are effective methods to clear biofilms. However, large and controlled delivery of NO gas molecules is currently a great challenge. Methods: The core-shell structure of Ag₂S@ZIF-90/Arg/ICG was developed and characterized in detail. The ability of Ag₂S@ZIF-90/Arg/ICG to produce heat, ROS and NO under 808 nm NIR excitation was detected by an infrared thermal camera, probes and Griess assay. In vitro anti-biofilm effects were evaluated by CFU, Dead/Live staining and MTT assays. Hematoxylin-eosin staining, Masson staining and immunofluorescence staining were used to analyze the therapeutic effects in vivo. Results: Antibacterial photothermal therapy (aPTT) and antibacterial photodynamic therapy (aPDT) could be excited by 808 nm NIR light, and the produced heat and ROS further triggered the release of NO gas molecules simultaneously. The antibiofilm effect had a 4-log reduction in vitro. The produced NO caused biofilm dispersion through the degradation of the c-di-AMP pathway and improved biofilm eradication performance. In addition, Ag₂S@ZIF-90/Arg/ICG had the best therapeutic effect on periodontitis and NIR II imaging ability in vivo. Conclusions: We successfully prepared a novel nanocomposite with NO synergistic aPTT and aPDT. It had an outstanding therapeutic effect in treating deep tissue biofilm infection. This study not only enriches the research on compound therapy with NO gas therapy but also provides a new solution for other biofilm infection diseases.

Metabolic shift and the effect of mitochondrial respiration on the osteogenic differentiation of dental pulp stem cells

Background

Metabolism shifts from glycolysis to mitochondrial oxidative phosphorylation are vital during the differentiation of stem cells. Mitochondria have a direct function in differentiation. However, the metabolic shift and the effect of mitochondria in regulating the osteogenic differentiation of human dental pulp stem cells (hDPSCs) remain unclear.

Methods

Human dental pulp stem cells were collected from five healthy donors. Osteogenic differentiation was induced by osteogenic induction medium. The activities of alkaline phosphatase, hexokinase, pyruvate kinase, and lactate dehydrogenase were analyzed by enzymatic activity kits. The extracellular acidification rate and the mitochondrial oxygen consumption rate were measured. The mRNA levels of COL-1, ALP, TFAM, and NRF1 were analyzed. The protein levels of p-AMPK and AMPK were detected by western blotting.

Results

Glycolysis decreased after a slight increase, while mitochondrial oxidative phosphorylation continued to increase when cells grew in osteogenic induction medium. Therefore, the metabolism of differentiating cells switched to mitochondrial respiration. Next, inhibiting mitochondrial respiration with carbonyl cyanide-chlorophenylhydrazone, a mitochondrial uncoupler inhibited hDPSCs differentiation with less ALP activity and decreased ALP and COL-1 mRNA expression. Furthermore, mitochondrial uncoupling led to AMPK activation. 5-Aminoimidazole-4-carboxamide ribonucleotide, an AMPK activator, simulated the effect of mitochondrial uncoupling by inhibiting osteogenic differentiation, mitochondrial biogenesis, and mitochondrial morphology. Mitochondrial uncoupling and activation of AMPK depressed mitochondrial oxidative phosphorylation and inhibited differentiation, suggesting that they may serve as regulators to halt osteogenic differentiation from impaired mitochondrial oxidative phosphorylation.

Double-Edged Sword Effect of Pyroptosis: The Role of Caspase-1/-4/-5/-11 in Different Levels of Apical Periodontitis

The study was to investigate the effect of canonical and noncanonical pyroptosis in apical periodontitis. Proteins' profiles of human apical periodontitis tissue were analyzed by label-free proteomics. Immunofluorescence was used to detect proteins related to pyroptosis in human apical periodontitis tissues and experimental apical periodontitis models. A dual experimental apical periodontitis model with both smaller (mandible) and larger (maxilla) bone lesions was established. THP-1-derived macrophages were stimulated with P. gingivalis lipopolysaccharide in vitro with or without the caspase-1/-4/-5 inhibitor Ac-FTDL-CMK. Propidium iodide staining, lactic dehydrogenase release and Western blot were applied to evaluate cell death and the protein expression. Caspase-1/-4/-5 were expressed in human apical periodontitis tissues. Caspase-1/-11 were involved in bone loss in experimental apical periodontitis. Caspase-1/-11 inhibitors reduced bone loss in larger lesions (maxilla) but accelerated bone loss in smaller lesions (mandible). Caspase-1/-4/-5 inhibitors also showed double-edged sword effects on propidium iodide staining and lactic dehydrogenase release in vitro. The expression of cleaved-caspase-1/-4/-5, mature interluekin-1β and gasdermin D N-terminal domain increased in THP-1-derived macrophages after lipopolysaccharide stimulation but decreased after treatment with Ac-FTDL-CMK. Pyroptosis contributed to apical periodontitis and excited a double-edged sword effect in inducing bone loss in vivo and cell death in vitro.

The Profile of Articles on AXIN2 Mutations, Oligodontia, and Ethical Statements in Dental Research

PURPOSE

Editors often require ethical statements in research publications. This is particularly important with genetic data where discrimination may occur upon data disclosures. The purpose of this research is to determine if there was a positive trend of publishing ethical statements in dental genetic research. The study is limited to AXIN2 mutations which may be associated with oligodontia and cancer.

METHODS

A MEDLINE search of 2011-2021 articles concerning AXIN2, oligodontia, and ethical statements was conducted. Reviews, nonhuman subject research, abstracts, and articles not written nor translated into English were excluded.

RESULTS

Forty-four studies were found; 10 excluded. There were 25 (75.8%) with ethical statements, and 25 (75.8%) with participant consent statements. There was no significant difference by year in ethical statements over the ten years (p = 0.094).

CONCLUSION

There is a need to encourage more ethical statements in publications especially for genetically sensitive topics to reassure readers of ethical practices.

Effect of inflammation on bones in diabetic patients with periodontitis via RANKL/OPG system-A review

Purpose

Diabetes mellitus and periodontitis are inflammatory diseases, the severity of inflammation results in the progression and persistence of both the disorders and affects bones. Diabetic complications aggravate in diabetic subjects having periodontitis; similarly, diabetic patients are more prone to developing gingivitis and periodontitis. Periodontal and diabetic inflammation disturbs bone homeostasis, which possibly involves both innate and adaptive immune responses. The pathogenic processes that link the two diseases are the focus of much research and it is likely that upregulated inflammation arising from each condition adversely affects the other. RANKL/OPG pathway plays a prominent role in periodontal and diabetic inflammation and bone resorption.

Method

This review article summarises the literature on the link between inflammatory cytokines and the prevalence of disturbed bone homeostasis in diabetic patients with periodontitis. An extensive search was done in PubMed, Scopus, Medline and Google Scholar databases between April 2003 and May 2021.

Result

A total of 27 articles, including pilot studies, case-control studies, cross-sectional studies, cohort studies, randomized control trials, longitudinal studies, descriptive studies and experimental studies, were included in our literature review.

Conclusion

Since RANKL/OPG are cytokines and have immune responses, regulating these cytokines expression will help control diabetes, periodontitis and bone homeostasis. The growing evidence of bone loss and increased fracture risk in diabetic patients with periodontitis makes it imperative that health professionals carry out planned treatment focusing on monitoring oral health in diabetic patients; bone markers should also be evaluated in patients with chronic periodontitis with an impaired glycemic state.

Review of Animal Models to Study Pulp Inflammation

Human dental pulp is a highly dynamic tissue equipped with a network of resident immunocompetent cells that play a major role in the defense against pathogens and during tissue injury. Animal studies are mandatory and complementary to in vitro experiments when studying the physiopathology of dental pulp, new diagnostic tools, or innovative therapeutic strategies. This animal approach makes it possible to define a benefit-risk ratio necessary to be subsequently tested in humans. Among the animal kingdom, rodents, rabbits, ferrets, swine, dogs, and non-human primates have been used to model human pulpitis. The diversity of animals found in studies indicate the difficulty of choosing the correct and most efficient model. Each animal model has its own characteristics that may be advantageous or limiting, according to the studied parameters. These elements have to be considered in preclinical studies. This article aims to provide a thorough understanding of the different animal models used to study pulp inflammation. This may help to find the most pertinent or appropriate animal model depending on the hypothesis investigated and the expected results.