Bending strength of zirconia/porcelain functionally graded materials prepared using spark plasma sintering.

Objectives: The purpose of this study was to fabricate functionally graded materials (FGMs) consisting of yttria-stabilised tetragonal zirconia polycrystal (Y-TZP) and porcelain using spark plasma sintering (SPS) and examine the influence of their microstructures and thermal stress on their bending strengths.

Methods: Two types of four-layered Y-TZP/porcelain FGMs having a constant layer thickness and a varying layer thickness, Y-TZP/porcelain composite materials having a microstructure corresponding to each layer in FGMs and monolithic materials of Y-TZP and porcelain were fabricated by SPS. The Y-TZP/porcelain volume fraction of each layer in FGMs was varied over 100/0-70/30.

Temperature triggered shape memory effect of transpolyisoprene-based polymer.

Introduction: Pure gutta-percha (trans-1, 4-polyisoprene [TPI]) has been used extensively as a main component of gutta-percha for root canal filling. TPI has the interesting shape memory property by cross-linking, and this polymer was commercialized under the product name of SMP-2 (Kuraray Corp, Kashima, Japan). Therefore, the purpose of this study was to examine the thermal properties and the mechanism of the shape memory function of cross-linked SMP-2.

dpr and sod in Streptococcus mutans are involved in coexistence with S. sanguinis, and PerR is associated with resistance to H2O2.

Large numbers of bacteria coexist in the oral cavity. Streptococcus sanguinis, one of the major bacteria in dental plaque, produces hydrogen peroxide (H(2)O(2)), which interferes with the growth of other bacteria. Streptococcus mutans, a cariogenic bacterium, can coexist with S.

Development of surface coating material for discolored tooth equipped with bleaching effect.

It is attempted to augment a coating resin with a bleaching effect to provide both short- and long-term whitening effects. Base resin containing sodium percarbonate (SPC) effectively bleached bovine teeth discolored by the Maillard reaction. SPC did not reduce Vickers hardness, but hardness in the hybrid material increased.

Periodontal disease and type 2 diabetes mellitus: is the HMGB1-RAGE axis the missing link?

Periodontitis is a major chronic inflammatory disease associated with increased production of numerous proinflammatory cytokines, which leads to the destruction of the periodontal tissue and ultimately loss of teeth. Periodontitis has powerful and multiple influences on the occurrence and severity of systemic conditions and diseases, such as diabetes mellitus, cardiovascular disease and respiratory disease. Meanwhile, diabetes is associated with increased prevalence, severity and progression of periodontal disease.

Hyperosmotic stress induces cell death in an odontoblast-lineage cell line.

Introduction: Osmotic stress is one of the stimulations related to dental pain caused by caries or dentin hypersensitivity. The mechanism of osmotic-induced dental pain is not completely understood. The purpose of this study was to examine the responses of odontoblasts under sucrose-induced hyperosmotic stress.

Anandamide induces matrix metalloproteinase-2 production through cannabinoid-1 receptor and transient receptor potential vanilloid-1 in human dental pulp cells in culture.

Introduction: Anandamide (N-arachidonoylethanolamine [AEA]) is one of the main endocannabinoids. Endocannabinoids are implicated in various physiological and pathologic functions, inducing not only nociception but also regeneration and inflammation. The role of the endocannabinoid system in peripheral organs was recently described.

MK615: a new therapeutic approach for the treatment of oral disease.

The oral cavity is inhabited by over 500 different bacterial species. Dental caries and periodontitis are major bacterial infectious diseases in the oral cavity. Prunus mume Sieb.

MK615 attenuates Porphyromonas gingivalis lipopolysaccharide-induced pro-inflammatory cytokine release via MAPK inactivation in murine macrophage-like RAW264.7 cells.

The Japanese apricot, known as Ume in Japanese, has been a traditional Japanese medicine for centuries, and is a familiar and commonly consumed food. The health benefits of Ume are now being widely recognized and have been strengthened by recent studies showing that MK615, an extract of compounds from Ume, has strong anticancer and anti-inflammatory effects. However, the potential role of MK615 in the periodontal field remains unknown.

Runt-related gene 2 is involved in the inhibition of matrix metalloproteinase-13 expression by roxithromycin in human gingival epithelial cell cultures.

Background And Objective: Matrix metalloproteinase (MMP)-13 has wide substrate specificity compared with other MMPs and appears to be involved in periodontitis. Previously, we reported that roxithromycin (RXM) inhibits vascular endothelial growth factor expression induced by tumour necrosis factor-alpha in human periodontal ligament cells, but little is known about the effect of RXM on MMP-13 expression in human gingival epithelial cells. We therefore examined the effect of RXM on MMP-13 mRNA expression and production in cultured human gingival epithelial cells.

Selective inhibition of Porphyromonas gingivalis growth by a factor Xa inhibitor, DX-9065a.

Background: Porphyromonas gingivalis is a causative bacterium of adult periodontitis. However, there is no drug specific for P. gingivalis and for its virulence factor.

Substance P activates p38 mitogen-activated protein kinase to promote IL-6 induction in human dental pulp fibroblasts.

Substance P (SP) induces the expression of proinflammatory cytokines, such as interleukin (IL)-6, which are implicated in pulp inflammation. To determine the signal pathway of SP-induced IL-6, we examined the activities of the mitogen-activated protein kinases (MAPKs) in human dental pulp cell (PF-10) cultures. SP induced the phosphorylation of p38 MAPK within 5 min; this activation persisted for up to 40 min and was independent of the activation of extracellular signal-related kinases (ERK-1 and ERK-2) that were induced after SP stimulation of PF-10 cells.

Expression and characterization of vanilloid receptor subtype 1 in human dental pulp cell cultures.

The expression of the vanilloid receptor subtype 1 (VR1, TRPV1) was detected in human dental pulp fibroblasts (PF-10) using RT-PCR, Western blotting, and immunocytochemical analysis. As revealed by ELISA, capsaicin induced IL-6 expression in PF-10 cells, and the VR1 antagonist capsazepine dose-dependently inhibited capsaicin-induced IL-6 production, indicating that capsaicin-induced IL-6 expression is related to VR1 activation. The interaction between capsaicin and mitogen-activated protein kinases (MAPKs) was investigated.

Film thickness and fluidity of various luting cements determined using a trial indentation meter.

Objectives: The purpose of this study was to evaluate a new trial apparatus which could measure film thickness (T(h)) under a low load, using an indenter.

Methods: Five commercial luting cements were measured using this apparatus. T(h) was determined using four kinds of indenter, which were 5.

Neuropeptide release from dental pulp cells by RgpB via proteinase-activated receptor-2 signaling.

Dental pulp inflammation often results from dissemination of periodontitis caused mostly by Porphyromonas gingivalis infection. Calcitonin gene-related peptide and substance P are proinflammatory neuropeptides that increase in inflamed pulp tissue. To study an involvement of the periodontitis pathogen and neuropeptides in pulp inflammation, we investigated human dental pulp cell neuropeptide release by arginine-specific cysteine protease (RgpB), a cysteine proteinase of P.

Substance P enhances expression of lipopolysaccharide-induced inflammatory factors in dental pulp cells.

To examine how substance P (SP) is related with dental pulp inflammation, we examined the effects of SP on expression of genes for inflammatory factors in human dental pulp cell cultures. Using reverse transcriptase-polymerase chain reaction, we found that Prevotella intermedia lipopolysaccharide (LPS) induced expression of SP and SP-receptor mRNAs, and that somatostatin inhibited the LPS-induced expression of SP mRNA. We also found that SP enhanced LPS-induced stimulation of NF-kappaB binding activity.

Polymerization contraction stresses of resin-based composite restorations within beveled cavity preparations of Class I restorations.

Purpose: To evaluate internal stresses resulting from polymerization of resin-based composite materials in cavity preparations beveled at the internal line angles or the cavosurface margin, compared with those in conventional butt-joint box-shaped cavity preparations.

Materials And Methods: Contraction stress generated in resin-based composite restorations placed in an experimental cavity preparation model was determined using micro-photoelastic analysis. Three types of cavity preparations simulating Class I restorations with bevels at internal line angles (1 mm and 2 mm deep), and at the cavosurface margin (2 mm deep) were prepared in a posterior composite model in order to obtain no marginal defect with the restorative composite.

Enhanced expression of vascular endothelial growth factor by periodontal pathogens in gingival fibroblasts.

Vascular endothelial growth factor (VEGF) has recently attracted attention as a potent inducer of vascular permeability and angiogenesis. Aberrant angiogenesis is often associated with lesion formation in chronic periodontitis. The aim of the present study was to investigate the properties of VEGF expression in human gingival fibroblasts (HGF) culture.

Interleukin-10 receptor expression in human dental pulp cells in response to lipopolysaccharide from Prevotella intermedia.

Interleukin-10 receptor (IL-10R) expression in human, dental pulp, fibroblast cultures was investigated by using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. After exposure to lipopolysaccharide (LPS) from Prevotella intermedia, the IL-10R mRNA levels increased after 4 h, peaked at 7 h, and dropped back to the unstimulated level at 24 h. Maximal production of the IL-10R protein in dental pulp fibroblast cultures was detected by Western blot analysis after 12 h of LPS stimulation.

Interleukin-10 inhibits expression of interleukin-6 and -8 mRNA in human dental pulp cell cultures via nuclear factor-kappaB deactivation.

The effects of interleukin (IL)-10 on the expression of IL-6 and IL-8 mRNA in human dental pulp cell cultures were investigated by using the Northern blot analysis. On stimulation with Prevotella intermedia lipopolysaccharide (PiLPS), IL-10 was produced in peripheral blood but was not detected in human dental pulp cell culture supernatants. IL-10 inhibited IL-8 mRNA expression, which is normally stimulated by PiLPS, IL-1alpha, and tumor necrosis factor-alpha and inhibited IL-6 mRNA expression, which is normally stimulated by IL-1alpha.

Human gingival CD14(+) fibroblasts primed with gamma interferon increase production of interleukin-8 in response to lipopolysaccharide through up-regulation of membrane CD14 and MyD88 mRNA expression.

Gamma interferon (IFN-gamma)-primed human gingival fibroblasts (HGF) have been shown to produce higher levels of interleukin-8 (IL-8) upon stimulation with bacterial products and inflammatory cytokines than nonprimed controls. In this study, we examined whether priming of HGF with IFN-gamma up-regulates IL-8 production by the cells in response to purified lipopolysaccharide (LPS). The priming effect of IFN-gamma was clearly observed in the high-CD14-expressing (CD14(high)) HGF but not in the low-CD14-expressing (CD14(low)) HGF.

Enhanced production of vascular endothelial growth factor by human monocytic cells stimulated with endotoxin through transcription factor SP-1.

The effect of endotoxin on the regulation of vascular endothelial growth factor (VEGF) mRNA expression in human monocytic (THP-1) cells was examined. Endotoxic lipopolysaccharide (LPS) from Escherichia coli and synthetic E. coli-type lipid A (LA-15-PP) enhanced VEGF mRNA expression.