Objective Sperparamagnetic material is widely used in tumor localization and treatment , but there are still few studies in bone tissue engineering .This study aims to investigate the osteogenic efficiency of superparamagnetic scaffolds poly lactic acid hydroxy acetic acid (PLGA)/iron-doped hydroxyapatite (Fe-HA) for repairing rabbit mandibular defects , as well as evaluating the biocompatibility of the material . Methods 36 New Zealand rabbits were randomly selected and randomly divided into 6 groups, control without and with static magnetic field ( SMF ) groups ( no material is implanted), PLGA scaffold without and with SMF groups (implanted PLGA), PLGA/Fe-HA scaffold without and with SMF groups ( im-planted PLGA/Fe-HA), each group has 6 rabbits.We created bilat-eral mandibular defect models , executed the rabbits at 4 weeks and 12 weeks post-surgery, marked the mandibular specimens which detected by general observation, Micro-CT and HE staining, and ana-lyzed the results of bone mineral density in defect area .The hematological detection , pathological examination of liver and kidney sam-ples were carried out at 12 weeks pot-surgery.. Results The PLGA/Fe-HA scaffold without and with SMF groups began to appear rough defect area edge , decreased defect diameter , new bone formation from 4 weeks; the defect area formed a smooth , continuous bone repair from 12 weeks.The PLGA scaffold without and with SMF groups appeared rough , irregular callus repair , visible boundary between defect edge and normal bone tissue .There are still have part of unrepaired bone defect in the center of defect area in the control without and with SMF groups.At 12 weeks , the bone mineral density of PLGA/Fe-HA scaffold with SMF group [(572.50±19.09) mgHA/cm3] , respectively, compared with the PLGA scaffold with SMF group [(467.00±6.24)mgHA/cm3], the control with SMF scaffold group [(480.00±2.08) mgHA/cm3], the PLGA/Fe-HA scaffold without SMF group [(461.00±19.79)mgHA/cm3], the PL-GA scaffold without SMF group [(446.00±11.31)mgHA/cm3] and the control without SMF group [(422.00±28.28) mgHA/cm3], all the differences were statistically significant ( P<0.05).The bone mineral density of PLGA/Fe-HA scaffold with SMF group at 4 weeks [(572.50±19.09)mgHA/cm3] was significantly higher than that at 12 weeks [(276.00±28.28)mgHA/cm3] (P<0.05), the differences between 4 weeks and 12 weeks in other groups were statistically significant (P<0.05). Conclusion The superparama-gentic PLGA/Fe-HA scaffolds can promote the repair of bone defect , optimize the osteogenic effect of the material with SMF .Also ,the scaffold showed a good biocompatibility .

Objective: To investigate the effects of PssL-NAC reactive oxygen species (ROS)-responsive nanoparticles on intracellular ROS production, inflammatory factor levels, collagen production, cell function and Toll-like receptor 4 (TLR4), NF-κB nuclear factor-κB (p65) pathway protein expression in human gingival fibroblasts (HGFs) induced by Porphyromonas gingivalis-lipopolysaccharide (P.g-LPS). Methods: This study was reviewed and approved by the ethics committee. PssL-NAC microspheres containing oil soluble antioxidant N-acetylcysteine (NAC) were obtained by connecting the hydrophobic end of polycaprolactone (PCL) and the hydrophilic end of polyethylene glycol (PEG) via thioketal (TK) bonds in response to ROS, and self loading in the aqueous and oil phases. After preparation of the PssL-NAC microspheres and aqueous NAC solution, successful synthesis of the nanoparticles was verified by transmission electron microscopy. Then, HGFs were exposed to P.g-LPS (0, 5, or 10 μg/mL), P.g-LPS (0, 5, or 10 μg/mL)+NAC, and P.g-LPS (0, 5, or 10 μg/mL)+PssL-NAC, and the ROS levels in the different groups were observed under confocal microscopy to determine the concentration of P.g-LPS for use in subsequent experiments. The groups were as follows: control group (no treatment), P.g-LPS group (HGFs treated with P.g-LPS), NAC group (HGFs treated with P.g-LPS and NAC), and PssL-NAC group (HGFs treated with P.g-LPS and PssL-NAC). Cell counting kit-8 (CCK-8) assays verified the biosafety of PssL-NAC. The ROS levels in the different groups were detected by DCFH-DA probes and observed via confocal microscopy. Real-time qPCR (RT-qPCR) was used to monitor the gene expression levels of the intracellular inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), collagen 1 (COL1) and collagen 3 (COL3). The effect of PssL-NAC on the migration of HGFs was observed via the scratch test. The protein expression of TLR4-NF-κB, and phosphorylated p65 (p-p65) in the TLR4-NF-κB pathway was evaluated by Western blot. Results: PssL-NAC had no significant effect on HGF proliferation (P>0.05). At elevated P.g-LPS concentrations, PssL-NAC maintained intracellular ROS levels approximately twice those in the control group (P<0.001). PssL-NAC significantly decreased P.g-LPS-induced IL-6 (P<0.001) and TNF-α (P<0.001) gene expression and increased COL1 gene expression (P<0.001). After P.g-LPS stimulation, PssL-NAC restored cell migration to the control level (P>0.05) and decreased the protein expression of TLR4 (P<0.001), p65 (P = 0.006), and p-p65 (P = 0.017) in the TLR4-NF-κB pathway. Conclusion PssL-NAC maintains the appropriate intracellular ROS concentration, alleviates P.g-LPS-induced inflammation in HGFs through the TLR4-NF-κB pathway, and restores the cell functions of collagen production and migration in an inflammatory environment.

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.
Humans ; Consensus ; Endodontics/methods* ; Tooth ; Printing, Three-Dimensional ; Dental Care ; Cone-Beam Computed Tomography ; Root Canal Therapy