Research progress in the pathogenesis mechanism of dental fluorosis / 中华口腔医学杂志

Dental fluorosis is a developmental disturbance of dental enamel caused by excessive fluoride intake during tooth development, leading to the changes in morphology, structure and function of tooth enamel, which can affect the aesthetics and function of teeth. There are many factors which may account for the occurrence of dental fluorosis. However, the pathogenesis mechanism underlying dental fluorosis has not been fully clarified.In recent years, researches in the fields of fluoride-induced stress response pathways, signaling pathways and apoptosis at the molecular and genetic level had provided extensive knowledge of dental fluorosis. This article focuses on the latest research progress in the mechanism of dental fluorosis, which include the effects of fluoride on ameloblasts and enamel matrix proteins, genetic polymorphism and dietary nutrients, in order to provide new references for the targeted prevention and treatment of dental fluorosis.

Research progress in the association of peri-implant diseases and metabolic syndrome / 中华口腔医学杂志

Peri-implant disease, an important group of diseases that cause implant failure, are associated with metabolic abnormality. Metabolic syndrome (MetS) is a common metabolic disorder comprising abdominal obesity, hyperglycemia, systemic hypertension and atherogenic dyslipidemia. Previous studies had reported that MetS and its diversified clinical manifestations might be associated with peri-implant diseases, but the relationship and underlying mechanisms were unclear. This review aims to explore the relationship between MetS and peri-implant disease, in order to provide beneficial reference for the prevention and treatment of peri-implant disease in patients with MetS.

Macrophage migration-inhibitory factors expression and its effects on proliferation in human dental pulps / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of macrophage migration-inhibitory factors (MIF) in clinically healthy and inflamed human pulp tissues and the effects of rhMIF on the proliferation of human dental pulp cells (HDPC).</p><p><b>METHODS</b>Immunohistochemistry was used to detect the localization of MIF expression in clinically healthy pulp and inflamed pulp tissues. Quantitative real-time polymerase chain reaction (PCR) was performed to evaluate the mRNA levels of MIF in pulp specimens. In addition, the culture supernatants of HDPC were collected after HDPC was stimulated by lipopolysaccharide (LPS) for 24 h, and then the MIF levels were assayed by quantitative sandwich enzyme-linked immunosorbent assay. Meanwhile, the effects of rhMIF on the proliferation of HDPC at different concentrations for 24 and 48 h were observed by cell counting kit-8 (CCK-8).</p><p><b>RESULTS</b>MIF was mainly distributed in odontoblasts of healthy pulp tissue, however, in inflamed pulp tissue, it was widely detected in fibroblasts, inflammatory infiltrates and endothelial cells as well as odontoblasts. Quantitative real-time PCR showed that there was no significant difference in MIF mRNA levels between inflamed pulps and healthy pulps (P > 0.05). Additionally, the secretion of MIF was significantly increased by stimulation with LPS at the concentration of 0.1 and 1.0 mg/L [(1772.58 ± 495.05), (1692.58 ± 337.45) ng/L] (P < 0.05), and the concentration was (1048.53 ± 161.81) ng/L in control group. rhMIF stimulated the HDPC's proliferation at the concentration of 10, 30, 60 µg/L for 24 and 48 h.</p><p><b>CONCLUSIONS</b>MIF was expressed in pulp tissue and its expression was increased after stimulation by LPS. rhMIF increased the proliferation of HDPC. These results suggest that MIF may be involved in the process of pulpal inflammation.</p>

The antagonistic effect of the oral Streptococcus on the Saccharomyces albicans in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the antagonistic effects of three species of oral Streptococcus on the growth of oral Saccharomyces albicans in vitro.</p><p><b>METHODS</b>Direct inoculation method, reverse inoculation method and mixed culture methods were respectively chosen to observe the changes of Saccharomyces albicans colony formation on the effects of Streptococcus mutans, Streptococcus sanguis and Streptococcus salivarius.</p><p><b>RESULTS</b>1) No clear inhibition zone was observed in each of the groups by direct inoculation method. 2) Compared with the control groups, Saccharomyces albicans colony formation on soft agar of Streptococcus sanguis decreased significantly (P < 0.05). 3) Mixed culture method results showed that Streptococcus mutans could inhibit the growth of Saccharomyces albicans significantly at different time points (P = 0.001). 4) Under the action of bacteria culture supernatant, the count of Saccharomyces albicans in experiment groups showed statistical significance when compared with the control groups at 24, 48, 72 h (P = 0.001); The differences among the experimental groups were of no statistical significance at majority times (P > 0.05).</p><p><b>CONCLUSION</b>Streptococcus mutans, Streptococcus sanguis, and Streptococcus salivarius could obviously inhibit the growth of Saccharomyces albicans in vitro. However, it is still unclear that among which the inhibition effects is stronger. The antagonistic effects is weakened gradually.</p>

HSP25 affects the proliferation and differentiation of rat dental follicle cells / 国际口腔科学杂志·英文版

<p><b>AIM</b>To detect the expression of HSP25 in rat dental follicles both in vivo and vitro, and explore the underlying mechanism of HSP25 on the proliferation and differentiation of rat dental follicle cells (DFCs).</p><p><b>METHODOLOGY</b>Immunohistochemistry was performed to detect the expression of HSP25 in mandibles of postnatal rats on days 1, 3, 5, 7, 9 and 11 in vivo. In vitro, the expression of HSP25 in DFCs was detected by an indirect immunofluorescence assay. Thiazolyl blue tetrazolium bromide (MTT) assay, flow cytometry and alkaline phosphatase (ALP) assay were used to identify the time-course effect mediated by different concentrations of recombinant murine HSP25 of 0, 1, 10, 50 and 100 ng/mL on rat DFCs.</p><p><b>RESULTS</b>Expression of HSP25 was not detected in dental follicles of the rats until day 5 after birth, but became up-regulated in a time-dependent manner till day 11. HSP25 was detected in the cytoplasm of cultured rat DFCs. No significant difference could be observed in the proliferation of DFCs after stimulation with different concentrations of HSP25 on days 1, 2 and 3 (P > 0.05). HSP25 at concentrations of 50 ng/mL and 100 ng/mL up-regulated the ALP activity of DFCs on day 9 (P < 0.05).</p><p><b>CONCLUSION</b>HSP25-immunoreactivity increased chronologically during the development of dental follicles. The protein had no significant effect on cell proliferation but may play a role in cementoblast/osteoblast differentiation of DFCs.</p>

Expression and biological roles of heat shock protein 25 in rat dental follicle cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the expression of heat shock protein 25 (HSP-25) in dental rat follicles in vivo and in vitro in order to investigate the possible effect of HSP-25 on cell proliferation and alkaline phosphatase (ALP) activity.</p><p><b>METHODS</b>The expression of HSP-25 in mandibles of postnatal rats from day 1, 3, 5, 7, 9, 11 was examined by immunohistochemistry in vitro, the expression of HSP-25 in the dental follicle cells was detected by the indirect immunofluorescence method. Methyl thiazolyl tetrazolium (MTT) assay, flowcytometry and ALP assay were used to detect the effect of HSP-25 on rat dental follicles.</p><p><b>RESULTS</b>HSP-25 expression was absent or weak in rat dental follicle cells at early postnatal stage and present from day 5 till day 11. HSP-25 was detected in the cytoplasm of cultured dental follicle cells. MTT results showed no effect could be detected on dental follicle cell proliferation after stimulation of different concentrations of HSP-25 on day 1, 2, 3. Flowcytometry results also exhibited no difference in cell cycles after stimulation of HSP-25 at 0 microg/L and 100 microg/L. HSP-25 at a concentration of 50 microg/L and 100 microg/L could up-regulate the ALP activity on day 9.</p><p><b>CONCLUSIONS</b>Expression of HSP-25 increases chronologically in the rat dental follicle cells. HSP-25 locates in the cytoplasm of cultured rat dental follicle cells. HSP-25 has no effect on the proliferation of dental follicle cells, however it can up-regulate the ALP activity.</p>

Preliminary study on the discrimination of putative periodontal pathogens with a metabonomics method / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of identifying oral pathogenic bacteria by comparing the metabolic profiling of putative periodontal pathogens and try to find a convenient and rapid way to discriminate oral microorganisms.</p><p><b>METHODS</b>Suspensions of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum with same density were prepared and cultured respectively at liquid BHI medium. Then the growth quantity was measured periodically through turbidimetry and the growth curves of the inoculated bacteria were completed. The culture solutions of stable growth phase were sampled and characterized by 1H-nuclear magnetic resonance 1H-NMR). The data of 1H-NMR spectroscope results were analyzed by principal components analysis (PCA).</p><p><b>RESULTS</b>The PCA showed the obvious clustering phenomena and the points of three groups differentially centralized to three clusters. Therefore, the NMR-based metabonomics profiles could discriminate the three different kinds of bacteria.</p><p><b>CONCLUSION</b>The metabonomics is a potential classable method to identify the oral pathogenic bacteria.</p>

Study the inhibitory effects of three oral actinomyces on growth of oral Candida albicans in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of this study was to investigate whether the three species of oral Actinomyces have inhibitory effects on the growth of oral Candida albicans in vitro.</p><p><b>METHODS</b>Straight o'clock method was used to observe the bacteriostasis circle. Reverse o'clock and mixed culture method were used to study the quantitative changes of Candida albicans colony respectively.</p><p><b>RESULTS</b>(1) None of the groups had been viewed the bacteriostasis circle. (2) Compared with control groups, there was a significant decrease of Candida albicans colony on Actinomyces viscosus TPY soft agar (P < 0.05). Actinomyces naeslundii and Actinomyces odontolyticus TPY soft agar were both devoid of obvious Candida albicans colony (P < 0.01). The former group (Actinomyces viscosus) and the two latter groups (Actinomyces naeslundii and Actinomyces odontolyticus) showed a striking contrast (P < 0.01). (3) Compared with control groups, a decrease of Candida albicans showed up in the mixed culture, and the difference was significant (P < 0.05). The discrepancies among the three experimental groups were of no statistical value (P > 0.05).</p><p><b>CONCLUSION</b>Oral Actinomyces viscosus, Actinomyces naeslundii and Actinomyces odontolyticus could inhibit the growth of Candida albicans in vitro. However, which of them contributed more to the inhibitory effects was still not affirmed.</p>

Expression and significance of stromal cell-derived factor-1alpha and its receptor CXCR4 in human dental pulp cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of CXCR4 in cultured human dental pulp cells (HDPC) in vitro and the corresponding ligand SDF-1alpha level of HDPC supernatants stimulated by lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha), and to explore the role of SDF-1alpha on the proliferation and the migration of HDPC.</p><p><b>METHODS</b>The expression of CXCR4 in HDPC was detected by immunocytochemistry technique and indirect immunofluorescence technique. The culture supernatants of HDPC were collected after HDPC had been simulated by LPS and TNF-alpha of different concentrations for 48h and then the SDF-1alpha level was assayed by quantitative sandwich ELISA. Meanwhile, the effects of recombinant human SDF-1alpha (rhSDF-1alpha) on the proliferation and the migration of HDPC at different concentrations were observed by MTT and Boyden Chamber Assay.</p><p><b>RESULTS</b>CXCR4 was expressed in cytomembrane of HDPC and SDF-1alpha was secreted into their normal cell supernatants with a concentration of (4513.55 +/- 962.92) ng/L. The secretion of SDF-1alpha was both significantly decreased by stimulation with LPS and TNF-alpha (P < 0.05). In addition, rhSDF-1alpha stimulated the HDPC proliferation at the concentrations of 50, 100, 200 microg/L (P < 0.01) and increased the chemotactic migration of HDPC significantly after 9h's incubation with the concentrations of 50, 100 microg/L (P < 0.05).</p><p><b>CONCLUSIONS</b>SDF-1alpha accelerated the proliferation and the migration of HDPC which expressed CXCR4. SDF-1-CXCR4 axis may play a role in repair of pulp injury.</p>

Initial study on discrimination of oral microorganisms with the metabonomics technique / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of employing metabonomics method in identification of oral pathogenic bacteria.</p><p><b>METHODS</b>The Streptococcus mutans ATCC25175 and Actinomyces viscosus ATCC15987 were respectively inoculated in same certain culture medium. The growth curves of the inoculated bacteria were drown by turbidimetry. The culture solutions in four different growth phases of the both bacteria were used to test with the 1H-Nuclear magnetic resonance (1H-NMR) spectroscopy respectively. The data of 1H-NMR spectroscopy results were analyzed by principal components analysis (PCA).</p><p><b>RESULTS</b>The PCA showed the obvious clustering phenomena and the points of two group data stayed differentially together by two clusters. Therefore, the NMR-based metabonomics profiles can discriminate the two different kind of bacteria.</p><p><b>CONCLUSION</b>The metabonomics can be expected to be a kind of promising useful method in quick discrimination of oral pathogenic bacteria.</p>