Objective To investigate the effects of composite nanoparticles E/Ce@MCSNs loaded with epigallocatechin-3-gallate(EGCG)and cerium dioxide(CeO2)on the odonto/osteogenic differentiation of human stem cells from the apical papilla(SCAPs)and macrophage polarization under inflammatory conditions.Methods E/Ce@MCSNs were synthesized and characterized.Cell viabil-ity of SCAPs and RAW 264.7 cells treated with varying concentrations of E/Ce@MCSNs was assessed via CCK-8 assay.The antioxidant enzyme-mimetic activity of E/Ce@MCSNs was evaluated.Under simulated inflammatory conditions,intracellular reactive oxygen species(ROS)scavenging capacity was measured via DCFH-DA fluorescent probe.Alkaline phosphatase(ALP)staining/activity,alizarin red staining/semi-quantitative analysis,and RT-qPCR were performed to detect odonto/osteogenic differentiation markers,in-cluding dentin sialoprotein(DSPP),ALP,runt-related transcription factor 2(Runx-2),type Ⅰ collagen(COL-Ⅰ),and osteopontin(OPN)in SCAPs.The effects of E/Ce@MCSNs on the odontogenic/osteogenic differentiation of SCAPs under this condition were eval-uated.RT-qPCR were used to analyze cytokine expression(TNF-α,IL-1β,IL-6,iNOS,TGF-β,IL-10)and secreted TNF-α/IL-6 levels in RAW264.7 cells.The concentrations of TNF-α and IL-6 in cell cul-ture supernatants were measured by ELISA.Results E/Ce@MCSNs exhibited excellent biocompatibility at concentrations≤100 μg/mL.They demonstrated potent ROS-scavenging activity(P＜0.05)and sig-nificantly enhanced ALP activity(P＜0.001),promoted calcium nodule formation(P＜0.001),and upregulated odonto/osteogenic gene expression(DSPP,ALP,Runx-2,COL-Ⅰ,OPN)in SCAPs under inflammatory conditions(P＜0.05).In RAW264.7 cells,E/Ce@MCSNs downregulated pro-inflammatory cytokines(TNF-α,IL-1 β,IL-6,iNOS)(P＜0.01)and upregulated anti-inflammatory factors(TGF-β,IL-10)(P＜0.001),while reducing TNF-α and IL-6 secretion(P＜0.001).Conclusion E/Ce@MCSNs exert antioxidant and anti-inflammatory effects in apical periodontitis by scavenging excessive ROS,thereby promoting odonto/osteogenic differentiation of SCAPs.

Objective To investigate the effects of composite nanoparticles E/Ce@MCSNs loaded with epigallocatechin-3-gallate(EGCG)and cerium dioxide(CeO2)on the odonto/osteogenic differentiation of human stem cells from the apical papilla(SCAPs)and macrophage polarization under inflammatory conditions.Methods E/Ce@MCSNs were synthesized and characterized.Cell viabil-ity of SCAPs and RAW 264.7 cells treated with varying concentrations of E/Ce@MCSNs was assessed via CCK-8 assay.The antioxidant enzyme-mimetic activity of E/Ce@MCSNs was evaluated.Under simulated inflammatory conditions,intracellular reactive oxygen species(ROS)scavenging capacity was measured via DCFH-DA fluorescent probe.Alkaline phosphatase(ALP)staining/activity,alizarin red staining/semi-quantitative analysis,and RT-qPCR were performed to detect odonto/osteogenic differentiation markers,in-cluding dentin sialoprotein(DSPP),ALP,runt-related transcription factor 2(Runx-2),type Ⅰ collagen(COL-Ⅰ),and osteopontin(OPN)in SCAPs.The effects of E/Ce@MCSNs on the odontogenic/osteogenic differentiation of SCAPs under this condition were eval-uated.RT-qPCR were used to analyze cytokine expression(TNF-α,IL-1β,IL-6,iNOS,TGF-β,IL-10)and secreted TNF-α/IL-6 levels in RAW264.7 cells.The concentrations of TNF-α and IL-6 in cell cul-ture supernatants were measured by ELISA.Results E/Ce@MCSNs exhibited excellent biocompatibility at concentrations≤100 μg/mL.They demonstrated potent ROS-scavenging activity(P＜0.05)and sig-nificantly enhanced ALP activity(P＜0.001),promoted calcium nodule formation(P＜0.001),and upregulated odonto/osteogenic gene expression(DSPP,ALP,Runx-2,COL-Ⅰ,OPN)in SCAPs under inflammatory conditions(P＜0.05).In RAW264.7 cells,E/Ce@MCSNs downregulated pro-inflammatory cytokines(TNF-α,IL-1 β,IL-6,iNOS)(P＜0.01)and upregulated anti-inflammatory factors(TGF-β,IL-10)(P＜0.001),while reducing TNF-α and IL-6 secretion(P＜0.001).Conclusion E/Ce@MCSNs exert antioxidant and anti-inflammatory effects in apical periodontitis by scavenging excessive ROS,thereby promoting odonto/osteogenic differentiation of SCAPs.

Objective To investigate the antibacterial performance and biocompatibility of silver nanoparticles-coated root canal nickel titanium instruments(AgNPs-NiTi).Methods AgNPs-NiTi was prepared using pulse electrochemical deposition.The morphol-ogy of AgNPs-NiTi was observed using field emission scanning electron microscopy(FE-SEM),and the elemental composition and con-tent were analyzed using X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS).The mechanical properties of AgNPs-NiTi were tested.After Co-culturing AgNPs-NiTi with E.faecalis,the antibacterial effect was detected by colony-forming units method.By constructing an in vitro model of E.faecalis biofilm in the root canal of teeth,the antibacterial effect of AgNPs-NiTi was observed using FE-SEM and live/dead bacterial staining.In addition,AgNPs-NiTi was co-cultured with Raw 264.7 cells,and its cytotoxicity was de-tected by CCK-8.Results The pulse electrochemical deposition was used to construct a silver nanoparticle(AgNPs)coating on NiTi instruments with no significant change in the mechanical properties.AgNPs-NiTi significantly inhibited the proliferation of E.faecalis and damaged E.faecalis biofilm in the root canal.AgNPs-NiTi had no significant influence on the proliferation of Raw264.7 cells and had no cytotoxicity.Conclusion The mechanical properties of AgNPs-NiTi are similar to those of nickel titanium instruments.AgNPs-NiTi inhibits E.faecalis proliferation with good biocompatibility.

Objective To analyze three-dimensional(3D)radiographic characterizations of bone island(BI)in jaw using cone-beam computed tomography(CBCT).Methods CBCT data from four thousand patients were selected,reconstructed and analyzed using NNT 10.0 software.The sagittal,coronal and axial planes were used to analyze the 3D radiographic characteristics of BIs,including the localization,shape,density,boundary,the relationship between BIs and tooth and bone cortex,diameter and anatomical structures and complications involved.Their relationship with gender were analyzed.Results A total of 803 people had BIs,with the prevalence rate of 20.08%,including 338 males with 389 BIs and 465 females with 526 BIs.Both males and females had a dominant BI,and the ratio between male and female was 1∶1.38,but the difference was not statistically significant(P＞0.05).The BIs of both male and female mostly occurred in the mandibular premolars and molars area,and appeared irregular in shape,dense and contact with lingual bone cortex.Mostly BIs were apical type and with unclear boundary.The mean maximum diameter of mesial/distal direction was greater than buccal/lingual direction(P＜0.05).The most commonly involved anatomy structure was the inferior alveolar neural canal,cortical infil-tration and mental foramen.Conclusion There are no significant differences between males and females in the three-dimensional image characteristics of BIs in Chinese populations.CBCT can accurately and comprehensively analyze the 3D radiographic characteris-tics of BI and its relationship with the surrounding teeth and bone.