Activation of mitogen-activated protein kinases in satellite glial cells of the trigeminal ganglion contributes to substance P-mediated inflammatory pain

Inflammatory orofacial pain,in which substance P (SP) plays an important role,is closely related to the cross-talk between trigeminal ganglion (TG) neurons and satellite glial cells (SGCs).SGC activation is emerging as the key mechanism underlying inflammatory pain through different signalling mechanisms,including glial fibrillary acidic protein (GFAP) activation,phosphorylation of mitogen-activated protein kinase (MAPK) signalling pathways,and cytokine upregulation.However,in the TG,the mechanism underlying SP-mediated orofacial pain generated by SGCs is largely unknown.In this study,we investigated whether SP is involved in inflammatory orofacial pain by upregulating interleukin (IL)-1β and tumour necrosis factor (TNF)-α from SGCs,and we explored whether MAPK signalling pathways mediate the pain process.In the present study,complete Freund’s adjuvant (CFA) was injected into the whisker pad of rats to induce an inflammatory model in vivo.SP was administered to SGC cultures in vitro to confirm the effect of SP.Facial expression analysis showed that pre-injection of L703,606 (an NK-1 receptor antagonist),U0126 (an inhibitor of MAPK/extracellular signal-regulated kinase [ERK] kinase [MEK] 1/2),and SB203580 (an inhibitor of P38) into the TG to induce targeted prevention of the activation of the NK-1 receptor and the phosphorylation of MAPKs significantly suppressed CFA-induced inflammatory allodynia.In addition,SP promoted SGC activation,which was proven by increased GFAP,p-MAPKs,IL-1β and TNF-α in SGCs under inflammatory conditions.Moreover,the increase in IL-1β and TNF-α was suppressed by L703,606,U0126 and SB203580 in vivo and in vitro.These present findings suggested that SP,released from TG neurons,activated SGCs through the ERK1/2 and P38 pathways and promoted the production of IL-1β and TNF-α from SGCs,contributing to inflammatory orofacial pain associated with peripheral sensitization.

Histone methyltransferases and demethylases:regulators in balancing osteogenic and adipogenic differentiation of mesenchymal stem cells

Mesenchymal stem cells （MSCs） are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-based regenerative medicine, such as craniofacial bone regeneration, and in new treatments for metabolic bone diseases, such as osteoporosis. In recent years, histone modification has been a growing topic in the field of MSC lineage specification, in which the Su（var）3-9, enhancer-of-zeste, trithorax （SET） domain-containing family and the Jumonji C （JmjC） domain-containing family represent the major histone lysine methyltransferases （KMTs） and histone lysine demethylases （KDMs）, respectively. In this review, we summarize the current understanding of the epigenetic mechanisms by which SET domain-containine KMTs and JmiC domain-containinlz KDMs balance the osteogenic and adipogenic differentiation of MSCs.

Correction of mandibular deficiency by inverted-L osteotomy of ramus and iliac crest bone grafting

This study was to describe the use of inverted-L osteotomy of ramus and lilac bone graft for the management of mandibular deficiency in adult patients. From 2008 to 2010, 11 patients （aged 19 to 29 years） with mandibular deficiency underwent intraoral or extraoral inverted-L osteotomy of ramus and lilac crest bone grafting. Data were collected from the patients＇ records, photographs and radiographs. The height and width of the ramus were successfully expanded by inverted-L osteotomy and lilac crest bone grafting with minimal complications in all patients, resulting in significant improvement in occlusion and facial appearance. Our early results showed that the inverted-L osteotomy of ramus and lilac crest bone grafting is safe and effective, and should be considered as a good alternative for the patients with mandibular deficiency.

Honokiol:a promising small molecular weight natural agent for the growth inhibition of oral squamous cell carcinoma cells

Honokiol （HNK） is a small organic molecule purified from magnolia species and has demonstrated anticancer activities in a variety of cancer cell lines; however, its effect on oral squamous cell carcinoma （OSCC） cells is unknown. We investigated the antitumor activities of HNK on OSCC ceils in vitro for the first time. The inhibitory effects of HNK on the growth and proliferation of OSCC cells were demonstrated via in vitro 3-（4,5-dimethyl thiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and propidium iodide （PI） assays, and the apoptotic cells were investigated by the observation of morphological changes and detection of DNA fragmentation via PI, TdT-mediated dUTP-biotin nick end labeling （TUNEL）, and DNA ladder assays, as well as flow cytometry assay. The results showed that HNK inhibited the growth and proliferation of OSCC cells in vitro in a time and dose-dependent manner. The inhibitory effect was associated with the cell apoptosis induced by HNK, evidenced by the morphological features of apoptotic cells, TUNEL-positive cells and a degradation of chromosomal DNA into small internucleosomal fragments. The study also demonstrated here that the inhibition or apoptosis mediated by 15 μg.mL-1 or 20 μg.mL-1 of HNK were more stronger compared with those of 20 μg-mL-1 5-fluorouracil （5-Fu, the control） applied to OSCC cells, when the ratio of OSCC cell numbers were measured between the treatment of different concentrations of HNK to the 5-Fu treatment for 48 h. HNK is a promising compound that can be potentially used as a novel treatment agent for human OSCC.

The effect of cold-light-activated bleaching treatment on enamel surfaces in vitro

This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.

One-year water-ageing of calcium phosphate composite containing nano-silver and quaternary ammonium to inhibit biofilms

Dental composites are commonly used restorative materials; however, secondary caries due to biofilm acids remains a major problem. The objectives of this study were （1） to develop a composite containing quaternary ammonium dimethacrylate （QADM）, nanoparticles of silver （NAg）, and nanoparticles of amorphous calcium phosphate （NACP）, and （2） to conduct the first investigation of the mechanical properties, biofilm response and acid production vs water-ageing time from 1 day to 12 months. A 4 x 5 design was utilized, with four composites （NACP-QADM composite, NACP-NAg composite, NACP-QADM-NAg composite, and a commercial control composite）, and five water-ageing time periods （1 day, and 3, 6, 9, and 12 months）. After each water- ageing period, the mechanical properties of the resins were measured in a three-point flexure, and antibacterial properties were tested via a dental plaque biofilm model using human saliva as an inoculum. After 12 months of water-ageing, NACP-QADM- NAg had a flexural strength and elastic modulus matching those of the commercial control （P〉 0.1）. Incorporation of QADM or NAg into the NACP composite greatly reduced biofilm viability, metabolic activity and acid production. A composite containing both QADM and NAg possessed a stronger antibacterial capability than one with QADM or NAg alone （P〈0.05）. The anti-biofilm activity was maintained after 12 months of water-ageing and showed no significant decrease with increasing time （P〉0.1）. In conclusion, the NACP-QADM-NAg composite decreased biofilm viability and lactic acid production, while matching the load- bearing capability of a commercial composite. There was no decrease in its antibacterial properties after 1 year of water-ageing. The durable antibacterial and mechanical properties indicate that NACP-QADM-NAg composites may be useful in dental restorations to combat caries.

Validity assessment and determination of the cutoff value for the Index of Complexity, Outcome and Need among 12-13 year-olds in Southern Chinese

To validate the use of the Index of Complexity, Outcome and Need （ICON） in assessing orthodontic treatment need among 12-13 year-olds in southern China, we determined the threshold value of ICON based on Chinese orthodontists＇ judgments. The samples consisted of 335 students in grade 7 from 16 randomly selected middle schools in Chengdu, China. Three associate professors provided ICON scores for each participant and the results were compared with the gold standard judgments from 25 experts on treatment needs. Based on the gold standard, 195 casts belonged to the treatment category, while the rest 140 belonged to the no-treatment category. With the international cutoff point of 43, the sensitivity and specificity of the iCON score were 0.29 and 0.98. The best compromise between sensitivity and specificity in Chengdu, compared with the gold standard, was found at a cutoff point of 29, and the sensitivity and specificity were 0.88 and 0.83. When used to evaluate the treatment need of 12-13 year-olds in southern China, the international ICON cutoff value did not correspond well with Chinese orthodontists＇ judgments; a lower cutoff value of 29 offered a ~reater sensitivitv and soecificitv with respect to exoert orthodontists＇ oerceotion of treatment need.

Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling

Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as ＂bait＂： Fusobacterium nucleatum （F. nucleatum） whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans （S. mutans） whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the ＂bait＂ oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The ＂prey＂ bacterial mixtures （including known species or natural saliva samples） were added, unbound ceils were washed off after the incubation period and the remaining cells were eluted using 0.2 mol.L1 glycine. Genomic DNA was extraeted, subjeeted to 16S rRNA PCR amplification and separation of the resulting PCR produets by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F.. nucleatum adhered to a variety of bacterial species including uncultivable and uneharacterized onesl This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species.

Three-dimensional reconstruction of systematic histological sections:application to observations on palatal shelf elevation

Normal mammalian secondary palate development undergoes a series of processes,including palatal shelf(PS)growth,elevation,adhesion and fusion,and palatal bone formation.It has been estimated that more than 90%of isolated cleft palate is caused by defects associated with the elevation process.However,because of the rapidly completed elevation process,the entire process of elevation will never be easy to clarify.In this article,we present a novel method for three-dimensional(3D)reconstruction of thick tissue blocks from two-dimensional(2D)histological sections.We established multiplanar sections of the palate and tongue in coronal and sagittal directions,and further performed 3D reconstruction to observe the morphological interaction and connection between the two components prior to and during elevation.The method completes an imaging system for simultaneous morphological analysis of thick tissue samples using both synthetic and real data.The new method will provide a comprehensive picture of reorientation morphology and gene expression pattern during the palatal elevation process.

PPAR-γactivation promotes xenogenic bioroot regeneration by attenuating the xenograft induced-oxidative stress

Xenogenic organ transplantation has been considered the most promising strategy in providing possible substitutes with the physiological function of the failing organs as well as solving the problem of insufficient donor sources.However,the xenograft,suffered from immune rejection and ischemia-reperfusion injury(IRI),causes massive reactive oxygen species(ROS)expression and the subsequent cell apoptosis,leading to the xenograft failure.Our previous study found a positive role of PPAR-γ in antiinflammation through its immunomodulation effects,which inspires us to apply PPAR-γ agonist rosiglitazone(RSG)to address survival issue of xenograft with the potential to eliminate the excessive ROS.In this study,xenogenic bioroot was constructed by wrapping the dental follicle cells(DFC)with porcine extracellular matrix(p ECM).The hydrogen peroxide(H_(2)O_(2))-induced DFC was pretreated with RSG to observe its protection on the damaged biological function.Immunoflourescence staining and transmission electron microscope were used to detect the intracellular ROS level.SD rat orthotopic transplantation model and superoxide dismutase 1(SOD1)knockout mice subcutaneous transplantation model were applied to explore the regenerative outcome of the xenograft.It showed that RSG pretreatment significantly reduced the adverse effects of H2O2on DFC with decreased intracellular ROS expression and alleviated mitochondrial damage.In vivo results confirmed RSG administration substantially enhanced the host’s antioxidant capacity with reduced osteoclasts formation and increased periodontal ligament-like tissue regeneration efficiency,maximumly maintaining the xenograft function.We considered that RSG preconditioning could preserve the biological properties of the transplanted stem cells under oxidative stress(OS)microenvironment and promote organ regeneration by attenuating the inflammatory reaction and OS injury.

microRNAs, an active and versatile group in cancers

microRNAs （miRNAs） are a class of non-coding RNAs that function as endogenous triggers of the RNA interference pathway. Studies have shown that thousands of human protein-coding genes are regulated by miRNAs, indicating that miRNAs are master regulators of many important biological processes, such as cancer development, miRNAs frequently have deregulated expression in many types of human cancers, and play critical roles in tumorigenesis, which functions either as tumor suppressors or as oncogenes. Recent studies have shown that miRNAs are highly related with cancer progression, including initiating, growth, apoptosis, invasion, and metastasis. Furthermore, miRNAs are shown to be responsible for the cancer-related inflam- mation, anti-cancer drug resistance, and regulation of cancer stem ceils. Therefore, miRNAs have generated great interest as a novel strategy in cancer diagnosis and therapy. Here we review the versatile roles of miRNAs in cancers and their potential applications for diagnosis, prognosis, and treatment as biomarkers.

New strategies against drug resistance to herpes simplex virus

Herpes simplex virus （HSV）, a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir （ACV） and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets （the DNA helicase/primase （H/P） complex）, new types of molecules （nature products） and new antiviral mechanisms （lethal mutagenesis of Janus-type nucleosides） to fight the drug resistance of HSV.

Tooth anatomy risk factors influencing root canal working length accessibility

The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases （amounting to a total of 1 005 root canals） were examined. The anatomy risk factors assessed in each case included： tooth type （tooth location）, root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type （tooth iocation）, root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility （P〈0.05）. Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure.

Primer containing dimethylaminododecyl methacrylate kills bacteria impregnated in human dentin blocks

Antibacterial dimethylaminododecyl methacrylate （DMADDM） was recently synthesized. The objectives of this study were to： （1） investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and （2） compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate （QADM）. Scotchbond Multi-Purpose （SBMP） bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested： SBMP control primer P, P＋2.5% DMADDM, P＋5% DMADDM, P＋7.5% DMADDM, P＋10% DMADDM, and P＋10% QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units （CFU） and inhibition zones were measured. The bacterial inhibition zone of P＋10% DMADDM was 10 times that of control primer （P〈0.05）. CFU in dentin with P＋10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups （P〉0.1）. In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promisine for use in bonding agents as well as in other restorative and oreventive materials to inhibit bacteria.

小鼠成骨细胞Wnt信号通路相关因子表达与胰岛素样生长因子1的影响

背景:胰岛素样生长因子1可促进细胞增殖、分化,但其具体作用机制尚不清楚。目的:观察胰岛素样生长因子1对小鼠成骨细胞增殖﹑分化的影响,及Wnt信号通路相关因子mRNA的表达。方法:向体外培养的小鼠成骨细胞中加入25μg/L的胰岛素样生长因子1,分别于培养的第1,2,3,4,5天用CCK-8比色法检测细胞增殖率;于培养的第3,6,9天应用酶联免疫法检测细胞内碱性磷酸酶活性;细胞培养第3天提取总RNA,采用Real-timeRT-PCR检测Wnt-3a,低密度脂蛋白受体相关蛋白5,β-catenin mRNA的表达。结果与结论:25μg/L胰岛素样生长因子1能够促进成骨细胞增殖,提高碱性磷酸酶活性,而且明显增加成骨细胞中Wnt-3a、低密度脂蛋白受体相关蛋白5、β-catenin mRNA的表达(P<0.05)。说明胰岛素样生长因子1能够促进成骨细胞的增殖和分化,Wnt信号通路参与了该调控过程。

Common dental diseases in children and malocclusion

Malocclusion is a worldwide dental problem that influences the affected individuals to varying degrees. Many factors contribute to the anomaly in dentition, including hereditary and environmental aspects. Dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, and oral habits are most common dental diseases in children that strongly relate to malocclusion. Management of oral health in the early childhood stage is carried out in clinic work of pediatric dentistry to minimize the unwanted effect of these diseases on dentition. This article highlights these diseases and their impacts on malocclusion in sequence. Prevention, treatment, and management of these conditions are also illustrated in order to achieve successful oral health for children and adolescents, even for their adult stage.

Bivalent histone modifications during tooth development

Histone methylation is one of the most widely studied post-transcriptional modifications. It is thought to be an important epigenetic event that is closely associated with cell fate determination and differentiation. To explore the spatiotemporal expression of histone H3 lysine 4trimethylation（H3K4me3） and histone H3 lysine 27 trimethylation（H3K27me3） epigenetic marks and methylation or demethylation transferases in tooth organ development, we measured the expression of SET7, EZH2, KDM5 B and JMJD3 via immunohistochemistry and quantitative polymerase chain reaction（qP CR） analysis in the first molar of BALB/c mice embryos at E13.5, E15.5, E17.5, P0 and P3, respectively. We also measured the expression of H3K4me3 and H3K27me3 with immunofluorescence staining. During murine tooth germ development, methylation or demethylation transferases were expressed in a spatial–temporal manner. The bivalent modification characterized by H3K4me3 and H3K27me3 can be found during the tooth germ development, as shown by immunofluorescence. The expression of SET7, EZH2 as methylation transferases and KDM5 B and JMJD3 as demethylation transferases indicated accordingly with the expression of H3K4me3 and H3K27me3 respectively to some extent. The bivalent histone may play a critical role in tooth organ development via the regulation of cell differentiation.

Expert consensus on early childhood caries management

Early childhood caries(ECC)is a significant chronic disease of childhood and a rising public health burden worldwide.ECC may cause a higher risk of new caries lesions in both primary and permanent dentition,affecting lifelong oral health.The occurrence of ECC has been closely related to the core microbiome change in the oral cavity,which may be influenced by diet habits,oral health management,fluoride use,and dental manipulations.So,it is essential to improve parental oral health and awareness of health care,to establish a dental home at the early stage of childhood,and make an individualized caries management plan.Dental interventions according to the minimally invasive concept should be carried out to treat dental caries.This expert consensus mainly discusses the etiology of ECC,caries-risk assessment of children,prevention and treatment plan of ECC,aiming to achieve lifelong oral health.

Spatial signalling mediated by the transforming growth factor-β signalling pathway during tooth formation

Tooth development relies on sequential and reciprocal interactions between the epithelial and mesenchymal tissues, and it is continuously regulated by a variety of conserved and specific temporal-spatial signalling pathways. It is well known that suspensions of tooth germ cells can form tooth-like structures after losing the positional information provided by the epithelial and mesenchymal tissues. However, the particular stage in which the tooth germ cells start to form tooth-like structures after losing their positional information remains unclear. In this study, we investigated the reassociation of tooth germ cells suspension from different morphological stages during tooth development and the phosphorylation of Smad2/3 in this process. Four tooth morphological stages were designed in this study. The results showed that tooth germ cells formed odontogenic tissue at embryonic day （E） 14.5, which is referred to as the cap stage, and they formed tooth-like structures at E16.5, which is referred to as the early bell stage, and E18.5, which is referred to as the late bell stage. Moreover, the transforming growth factor-β signalling pathway might play a role in this process.

Ferroptosis molecular inducers:A future direction for malignant tumor chemotherapy

Iron-dependent ferroptosis is a form of cell death dependent on iron levels.Cells that undergo ferroptosis have glutathione(GSH)deficiency,reduced Glutathione peroxidase-4(GPX4)activity and intracellular lipid peroxidation,Mitochondria,lysosomes and many signal pathways are involved in the regulation of ferroptosis.More importantly,many tumor cells resistant to other cell death methods exhibit sensitivity to ferroptosis.Moreover,over recent years,a number of ferroptosis-induced drugs have been recommended for the treatment of malignant tumors.Therefore,the study of ferroptosis is of great significance for future cancer treatments.In this review,we discussed the metabolic process of ferroptosis,the role of different organelles,the typical signaling pathways involved in ferroptosis,as well as natural and synthetic compounds that can induce ferroptosis,aiming to point out new conceptual avenues for utilizing ferroptosis in future cancer treatments.