Co-Cr dental alloys induces cytotoxicity and inflammatory responses via activation of Nrf2/antioxidant signaling pathways in human gingival fibroblasts and osteoblasts.

Objective: Although cobalt-chromium (Co-Cr) dental alloys are routinely used in prosthodontics, the biocompatibility of Co-Cr alloys is controversial. The aims of the present study were to investigate the effects of Co-Cr alloys on human gingival fibroblasts (HGF) and osteoblasts in an in vitro model as well as their potential molecular mechanisms, focusing on NF-E2-related factor 2 (Nrf2) pathways.

Methods: Cells were directly seeded on prepared Co-Cr alloy discs (15.

Genome sequence of Prevotella intermedia SUNY aB G8-9K-3, a biofilm forming strain with drug-resistance.

Prevotella intermedia has long been known to be as the principal etiologic agent of periodontal diseases and associated with various systemic diseases. Previous studies showed that the intra-species difference exists in capacity of biofilm formation, antibiotic resistance, and serological reaction among P. intermedia strains.

An Overview of Pathogen Recognition Receptors for Innate Immunity in Dental Pulp.

Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution.

Effects of moderate intensity static magnetic fields on human bone marrow-derived mesenchymal stem cells.

This study aimed to explore effects of static magnetic fields (SMFs) of moderate intensity (3-50 mT) as biophysical stimulators of proliferation and osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs). MSCs were exposed to SMFs of three intensities: 3, 15, and 50 mT. Proliferation was assessed by cell counting and bromodeoxyuridine incorporation, and differentiation by measuring alkaline phosphatase (ALP) activity, calcium content, mineralized nodule formation, and transcripts of osteogenic markers.

ACE insertion/deletion polymorphism is associated with periodontal disease in Korean population.

Objective: Angiotensin-converting enzyme (ACE) is the core enzyme in the renin-angiotensin system (RAS), which catalyzes the production of angiotensin II (Ang II). The aim of this study was to determine whether ACE gene is associated with the development of the periodontal disease.

Design: To investigate whether ACE is involved in the development of the periodontal disease, 199 periodontal disease patients and 165 control subjects were studied.

PIN1 inhibition suppresses osteoclast differentiation and inflammatory responses.

Inflammatory responses and osteoclast differentiation play pivotal roles in the pathogenesis of osteolytic bone diseases such as periodontitis. Although overexpression or inhibition of peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (PIN1) offers a possible therapeutic strategy for chronic inflammatory diseases, the role of PIN1 in periodontal disease is unclear. The aim of the present study was to evaluate PIN1 expression in periodontitis patients as well as the effects of PIN1 inhibition by juglone or PIN1 small-interfering RNA (siRNA) and of PIN1 overexpression using a recombinant adenovirus encoding PIN1 (Ad-PIN1) on the inflammatory response and osteoclastic differentiation in lipopolysaccharide (LPS)- and nicotine-stimulated human periodontal ligament cells (PDLCs).

Enhanced neural cell adhesion and neurite outgrowth on graphene-based biomimetic substrates.

Neural cell adhesion and neurite outgrowth were examined on graphene-based biomimetic substrates. The biocompatibility of carbon nanomaterials such as graphene and carbon nanotubes (CNTs), that is, single-walled and multiwalled CNTs, against pheochromocytoma-derived PC-12 neural cells was also evaluated by quantifying metabolic activity (with WST-8 assay), intracellular oxidative stress (with ROS assay), and membrane integrity (with LDH assay). Graphene films were grown by using chemical vapor deposition and were then coated onto glass coverslips by using the scooping method.

Involvement of SDF-1 and monocyte chemoattractant protein-1 in hydrogen peroxide-induced extracellular matrix degradation in human dental pulp cells.

Aim: To determine whether chemokines such as SDF-1 and monocyte chemoattractant protein-1 (MCP-1) are responsible for hydrogen peroxide (H2 O2 )-induced extracellular matrix (ECM) degradation and to identify the underlying mechanism in human dental pulp cells (HDPCs).

Method: Human dental pulp cells were exposed to 0.4 mmol H2 O2 for 48 h.

The role of thymosin beta 4 on odontogenic differentiation in human dental pulp cells.

We recently reported that overexpression of thymosin beta-4 (Tβ4) in transgenic mice promotes abnormal hair growth and tooth development, but the role of Tβ4 in dental pulp regeneration was not completely understood. The aim of this study was to investigate the role of Tβ4 on odontoblastic differentiation and the underlying mechanism regulating pulp regeneration in human dental pulp cells (HDPCs). Our results demonstrate that mRNA and protein expression of Tβ4 is upregulated during odontogenic differentiation in HDPCs.

Sodium hydrogen sulfide inhibits nicotine and lipopolysaccharide-induced osteoclastic differentiation and reversed osteoblastic differentiation in human periodontal ligament cells.

Although previous studies have demonstrated that hydrogen sulfide (H(2)S) stimulated or inhibited osteoclastic differentiation, little is known about the effects of H(2)S on the differentiation of osteoblasts and osteoclasts. To determine the possible bioactivities of H(2)S on bone metabolism, we investigated the in vitro effects of H(2)S on cytotoxicity, osteoblastic, and osteoclastic differentiation as well as the underlying mechanism in lipopolysaccharide (LPS) and nicotine-stimulated human periodontal ligament cells (hPDLCs). The H(2)S donor, NaHS, protected hPDLCs from nicotine and LPS-induced cytotoxicity and recovered nicotine- and LPS-downregulated osteoblastic differentiation, such as alkaline phosphatase (ALP) activity, mRNA expression of osteoblasts, including ALP, osteopontin (OPN), and osteocalcin (OCN), and mineralized nodule formation.

Odontogenic responses of human dental pulp cells to collagen/nanobioactive glass nanocomposites.

Objectives: Collagen-based nanocomposite incorporating nanobioactive glass (Col/nBG) was developed as a scaffolding matrix for dentin-pulp regeneration. The effects of the novel matrix on the proliferation of human dental pulp cells (hDPCs) and their differentiation into odontoblastic lineage were investigated.

Methods: Nanocomposite scaffold was prepared by incorporating nBG within the Col solution and then reconstituting them into a membrane form.

The role of SIRT1 on angiogenic and odontogenic potential in human dental pulp cells.

Introduction: Although several biological roles of SIRT1 have been reported, the expression and role of SIRT1 in human dental pulp cells (HDPCs) remain unknown. To identify the role of SIRT1 in HDPCS, we measured SIRT1 messenger RNA and protein levels during the odontoblastic differentiation of HDPCs. Additionally, we investigated the effects of SIRT1 overexpression and knockdown on the differentiation of HDPCs.

Nicotine and lipopolysaccharide stimulate the production of MMPs and prostaglandin E2 by hypoxia-inducible factor-1α up-regulation in human periodontal ligament cells.

Background And Objective:   Although hypoxia-inducible factor 1α (HIF-1α) is up-regulated in the periodontal pockets of periodontitis patients, the expression and precise molecular mechanisms of HIF-1α remain unknown in human periodontal ligament cells (PDLCs). The aim of this study was to explore the effects, as well as the signaling pathway, of nicotine and lipopolysaccharide (LPS) on the expression of HIF-1α and on the production of its target genes, including cyclooxygenase-2 (COX-2)-derived prostaglandin E(2) (PGE(2) ), MMP-2 and MMP-9 in PDLCs.

Material And Methods:   The expression of COX-2 and HIF-1α proteins was evaluated using western blotting.

Endoplasmic reticulum stress modulates nicotine-induced extracellular matrix degradation in human periodontal ligament cells.

Background And Objective: Tobacco smoking is considered to be one of the major risk factors for periodontitis. For example, about half the risk of periodontitis can be attributable to smoking in the USA. It is evident that smokers have greater bone loss, greater attachment loss and deeper periodontal pockets than nonsmoking patients.

Mechanical stress-activated immune response genes via Sirtuin 1 expression in human periodontal ligament cells.

Recently, Sirtuin 1 (SIRT1) has been implicated in the molecular control of ageing and immune response. Although the remodelling of periodontal ligament (PDL) in response to mechanical stress (MS) is mediated by several host factors, including cytokines and chemokines, the transmission of mechanical stimuli into specific cellular activity is still not understood fully. This study aimed to investigate the effects of MS, particularly cyclic strain, on immune response genes, as well as SIRT1 and its signal transduction pathways, in human PDL cells.

Effects of simvastain and enamel matrix derivative on Portland cement with bismuth oxide-induced growth and odontoblastic differentiation in human dental pulp cells.

Introduction: We previously reported that bismuth oxide containing Portland cement (BPC) showed similar biocompatibility to Portland cement (PC) in periodontal ligament cells. However, the bioactivity of simvastatin and Emdogain (Biora AB, Malmö, Sweden) on BPC was not reported. The aim of this study was to evaluate the effects of simvastatin and Emdogain on BPC compared with mineral trioxide aggregate (MTA) in human dental pulp cells (HDPCs).

Effects of recombinant dentin sialoprotein in dental pulp cells.

Dentin sialophosphoprotein (DSPP) is critical for dentin mineralization. However, the function of dentin sialoprotein (DSP), the cleaved product of DSPP, remains unclear. This study aimed to investigate the signal transduction pathways and effects of recombinant human DSP (rh-DSP) on proliferation, migration, and odontoblastic differentiation in human dental pulp cells (HDPCs).

Antioxidants, like coenzyme Q10, selenite, and curcumin, inhibited osteoclast differentiation by suppressing reactive oxygen species generation.

Coenzyme Q10 (CoQ10), selenium, and curcumin are known to be powerful antioxidants. Osteoclasts are capable of resorbing mineralized bone and excessive bone resorption by osteoclasts causes bone loss-related diseases. During osteoclast differentiation, the reactive oxygen species (ROS) acts as a secondary messenger on signal pathways.

Role of SIRT1 in heat stress- and lipopolysaccharide-induced immune and defense gene expression in human dental pulp cells.

Introduction: Although bacterial infection and heat stress are common causes of injury in human dental pulp cells (HDPCs), little is known about the potential defense mechanisms mediating their effects. This study examined the role of SIRT1 in mediating heat stress and lipopolysaccharide (LPS)-induced immune and defense gene expression in HDPCs.

Methods: HDPCs were exposed to heat stress (42°C) for 30 minutes after stimulation with LPS (1 μg/mL) for 48 hours.

Mechanism of sappanchalcone-induced growth inhibition and apoptosis in human oral cancer cells.

Sappanchalcone, a flavonoid extracted from Caesalpinia sappan, exhibits cytoprotective activity, but the molecular basis for the anticancer effect of sappanchalcone has not been reported. In this study, we examined whether sappanchalcone could inhibit the growth of human primary and metastatic oral cancer cells, and we analyzed the signaling pathway underlying the apoptotic effects of the compound in this process using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assays, fluorescence microscopy, flow cytometry, and Western blotting. Sappanchalcone-treated oral cancer cells showed an increased cytosolic level of cytochrome c, downregulated Bcl-2 expression, upregulated Bax and p53 expression, caspase-3 and -9 activation, and poly (ADP-ribose) polymerase cleavage.

The role of sirtuin 1 in osteoblastic differentiation in human periodontal ligament cells.

Background And Objective: Activation of sirtuin 1 (SIRT1) promotes the differentiation of keratinocytes and mesenchymal stem cells, but inhibits the differentiation of muscle and fat cells. However, the involvement of SIRT1 in the differentiation of human periodontal ligament cells into osteoblast-like cells remains unclear. To identify the role of SIRT1 in human periodontal ligament cells, we measured SIRT1 mRNA and SIRT1 protein levels during the osteoblastic differentiation of human periodontal ligament cells.

Smoking prevalence and attitude toward anti-smoking activities among Korean dentists.

Aims: To investigate the smoking habits and attitudes toward anti-smoking activities of Korean dentists according to their smoking status.

Methods: A questionnaire was mailed to a random sample of 2500 currently active Korean dentists in 2008. After 20% of the 1680 returned surveys (response rate 67.

Clustering of oral and general health risk behaviors in Korean adolescents: a national representative sample.

Purposes: To investigate the distribution of modifiable oral and general health risk behaviors according to socioeconomic status and to examine the extent of clustering of risk behaviors among Korean adolescents.

Methods: Self-reported data from 71,404 adolescents were obtained using a stratified cluster sample of students in the 7th to 12th grades who participated in the Korea Youth Risk Behavior Web-based Survey. Multiple logistic regression analysis was used to determine the influence of family affluence on health behaviors and the strength of associations of general health behaviors in models for oral health behaviors.

Volume-activated chloride currents from human fibroblasts: blockade by nimodipine.

The whole-cell patch clamp technique was used to identify and to characterize volume-activated Cl- current (ICl(vol)) in fibroblasts derived from human periodontal ligament. During osmotic cell swelling, the cells exhibited an outwardly rectifying current, which was dependent upon the concentration of external Cl-. The anion permeability sequence of the chloride channel for anions was as follows: SCN- > I- > Br- > Cl- > F- > methanesulphonate > gluconate.