Objective： To study the effect of secreted frizzled-related protein 2 (SFRP2) on lymph node T cells in C57 mice. Methods： SFRP2 recombinant protein was used to construct high concentration SFRP2. The total T cells of lymph node from C57 mouse were isolated and cultured in vitro. The effects of SFRP2 recombinant protein on proliferation, apoptosis and subpopulation of lymph node T cells in C57 mice were detected by flow cytometry. Results： SFRP2 (0.4 ng/mL) inhibited the proliferation of total T cells;SFRP2 (0.4 ng/mL)inhibited the early apoptosis of total T cells, has no significant effect on late apoptosis rate, and inhibits total apoptosis rate; SFRP2 (0.4 ng/mL) increases the proportion of Th1 subpopulations, decreases the proportion of Th2 subpopulations, and changes the Th1/Th2 balance. Conclusions： The results indicate that the concentration of SFRP2 (0.4 ng/mL) can inhibit the proliferation of total T cells, promote apoptosis, and affect the balance of Th1/Th2.

Objective： To study the effects of rapamycin on the cytological properties of mouse embryonic palatal cells (MEPCs). Methods： MEPCs were isolated from E13.5 mice embryos and treated with different concentrations of rapamycin (0, 5, 10, 50, 100 nmol/L) for 0, 3, 6, 12, 24, 48 h to observe cell viability, apoptosis, migration, and osteogenic differentiation capacity, while the most effective concentration was selected. Western blot method is used to detect LC3Ⅱ and p62/SQSTM1 expression level in the concentration. Results： Compared with the control group, rapamycin promoted cell proliferation, and the effect of 10 nmol/L rapamycin was the most obvious in 6 h. After 6 h, the inhibition of rapamycin was in a time-dependent manner for MEPCs proliferation. The longer the time was, the stronger the inhibition. Compared with the control group, rapamycin inhibited cell apoptosis and 10 nmol/L rapamycin had the most obvious effect in 6 h, and after 6 h, rapamycin promoted cell apoptosis. Rapamycin significantly promoted MEPCs migration in a dose- and time-dependent manner. Rapamycin inhibited the osteogenesis of MEPCs which was shown by ALP activity, Alizarin red staining and calcium ion in a time-dependent manner; RT-PCR assays showed that the expression of bone sialoprotein and osteocalcin was lower than the control group. Compared with control group, LC3 Ⅱ expression was increased, the expression of p62/SQSTM1 was significantly decreased, rapamycin induced autophagy in a time-dependent manner. Conclusions： Rapamycin can affect the cytological properties of palatal cells, which may be related to the induction of autophagy.

Objective： To investigate the effect of local application of resolvin E1 (RvE1) on periodontal inflammation in mice and its regulation of periodontal ligament cells. Methods： C57BL/6 mice were randomly divided into normal group, control group (periodontitis + PBS) and RvE1 group (periodontitis + RvE1). Silk ligation was used to construct periodontitis models on mice, RvE1 was locally injected every other day for 10 days in all. The inflammation changes in periodontium was compared. And the expression of ChemR23 was checked. Human periodontal ligament cells(hPDLCs) were isolated and cultured in vitro. 1 μg/mL lipopolysaccharide was added to culture medium to induce the inflammation condition. Different concentration of RvE1 was added, and then the expression of inflammatory factors, IL–1β, IL-6 and IL-8 was detected. Results： The inflammation infiltration was depressed with the local injections of RvE1. PDLCs express ChemR23 receptor around the nuclei in normal and inflammatory state. 1 nmol/L RvE1 suppressed the expression of IL–1β, IL-6 and IL-8 in periodontal ligament cells at RNA and protein levels. Conclusions： RvE1 inhibits the expression of inflammatory cytokines in periodontal ligament cells and suppresses the inflammatory status of periodontal tissues.

Objective： Using electrospinning to preparesilk fibroin/chitosan(SF/CS) nanofiber membrane scaffolds, and then evaluating its properties and effects on proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells(hBMSCs). Methods： The regenerated silk fibroin(SF) and chitosan(CS) were dissolved in the mixed solvent system of trifluoroacetic acid and dichloromethane by mass ratio (1:0, 1:1). SF and SF/CS nanofiber scaffolds then were prepared by electrospinning. The structure and properties of the electrospun films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravity/differential thermal gravity analysis (TG/DTG). Cells in the experimental group were inoculated on the surface of SF and SF/CS membrane respectively. Cells in the control group were directly inoculated in culture dish. hBMSCs were used in each group to induce osteogenesis. CCK-8 was used to study the growth and proliferation of cells. Energy dispersive spectrometer (EDS) and alizarin red staining (ARS) were used to detect the ability of osteogenesis and mineralization. Results： Compared with SF scaffolds, SF/CS scaffolds had more uniform fiber diameter (SEM) and more stable conformation (FTIR);TG/DTG results showed that SF scaffolds had more thermal stability. CCK-8 showed that compared with the control group, there was no significant difference in proliferation of hBMSCs between SF and SF/CS groups when co-cultured for 5 and 7 days(P>0.05). After 21 days of culture, elemental analysis indicated that the SF/CS group had higher calcium content. Compared with the control group and SF group, calcified nodules of hBMSCs in SF/CS group were significantly increased and staining was deep. Conclusions： Electrospinning SF/CS nanofibers scaffolds have good biocompatibility and can promote osteogenic differentiation of hBMSCs.

Objective： To investigate the effect of aging on the multi-directional differentiation ability of human periodontal ligament stem cells (PDLSCs). Methods： 14 healthy third molars were collected with complete roots in clinic and divided into two groups according to the donors’ ages: the younger group (donor age at 16-19 years) and the older group (donor age at 38-50 years). The periodontal ligament tissues were obtained and PDLSCs were isolated and cultured. Flow cytometry analysis was used to identify the phenotypes of PDLSCs. To compare the multi-directional differentiation ability of PDLSCs, cells were subjected to osteogenic and adipogenic induction in vitro respectively. Results： Flow cytometry analysis revealed that PDLSCs in both groups had the characteristics of mesenchymal stem cells. And the multi-directional differentiation ability of PDLSCs in the older group was significantly decreased compared with that in the younger group(P＜0.05). Conclusions： The multi-directional differentiation ability of PDLSCs decreased with age.

Objective: To study the difference of airway three-dimensional structure and condylar sagittal position in the glenoid fossa in skeletal class Ⅱ adults, and the relationship among them. Methods: 73 adult skeletal class Ⅱ orthodontic patients, CBCT was performed, and Dolphin Imaging 11.9 software was used to conduct 3D reconstruction and measurement of the subjects. Relevant measurements including ordinary cephalometric measurements SNA, SNB, FMA, ANB; airway related measurements upper airway superior plane sagittal distance Ls, inferior plane sagittal distance Li, superior plane cross-sectional area Ss, inferior plane cross-sectional area Ls, upper airway three-dimensional volume V, minimum cross-sectional area Smin, superior angle of upper airway As, inferior angle of upper airway Ai, total angle of upper airway (equals As+Ai); condylar sagittal position related measurements anterior articular space (left LDa, right RDa ), superior articular space (left LDs, right RDs ), posterior articular space (left LDp, right RDp ), linear ratio (left LLR, right RLR). Students’ t test and Pearson linear correlation analysis were performed using GraphPad Prism 7.0 software. Results: As for the difference between the skeletal class Ⅱ adult male orthodontic patients with retruded and normal mandible, there exists significant difference of Ai, A, LDp, LLRand RDp. For the female group, there exists significant difference of As and Ai. As for further analysis of above, for the male group, ANB has a relative correlation with Ai and A, and has aninverse correlation with LLR. As for the female group, ANB has an inverse correlation with Asand relative correlation with Ai. Conclusions: There exists relatively relationship among the retruded mandible, upper airway structure and condyle sagittal position.

Objective： To detect the relationship between the anatomical morphology in the maxillary second molar teeth and the number of root canals in a Chinese population by cone-beam CT images. Methods： 210 CBCT images with maxillary second molars (410 teeth) were randomly selected. The number of roots and root canals were observed and counted by Mimics 10.01 software. Three-dimensional reconstruction of maxillary second molars was performed. The buccolingual diameter and mesiodistal diameter were measured on three-dimensional reconstructed dental models. The relationship between the measurement results and the number of root canals, as well as the relationship between the occlusal morphology and the number of roots were analyzed. Results： 42.20% of the maxillary second molars had root fusion. Three canals were the most common form, and its incidence was 46.83%. The buccolingual diameter and mesiodistal diameter of the maxillary second molars with different root canal types were single canal ((10.21±0.50)mm, (8.82±0.17)mm), double canals ((11.25±0.55)mm, (9.47±0.42)mm), three canals ((11.68±0.68)mm, (9.47±0.54)mm), and four canals((12.01±0.63)mm, (9.52±0.57)mm). The buccolingual diameters of different root canal types were different significantly (P＜0.05). Except for single root canal, there was no significant difference in the mesiodistal diameters between other root canal types (P＞0.05). The ratio of buccolingual diameter and mesiodistal diameter corresponding to three and four root canals were also different from that of the other two root canal types (P＜0.05). The numbers of roost with different occlusal morphology were different (P＜0.05). Conclusions： There was a certain relationship between the anatomical shape and the number of root canals or roots in maxillary second molars, which could provide reference for clinical root canal therapy.

At present, the most commonly used dental CAD/CAM repair system is ceramic materials, which can be divided into rensin-matrix ceramics, polycrystalline ceramics and glass-matrix ceramics according to the composition differences. The composition of materials determines its characteristics. Different kinds of ceramics have great differences in mechanics and aesthetics. They are usually selected according to clinical needs and patients'needs. Each material has its own advantages and disadvantages, such as high transparency but brittle quality of glass-ceramics, high strength but low transparency of polycrystalline ceramics, rensin-matrix ceramics has both advantages of glass-ceramics and resin materials, but low strength. In this paper, the classification of their compositions, the characteristics of each type of ceramics and the research progress in recent years are reviewed systematically, which is helpful to guide clinical selection of CAD/CAM materials.