Objective：This study aimed at fabricating three-dimensional porous graphene (G) / poly(lactic-co-glycolic acid (PLGA) composite scaffolds and establishing the potential for further application of G/PLGA porous scaffolds in bone tissue engineering. Methods：Different concentrations of graphene was mixed with PLGA (G/PLGA, wt.‰: 0, 0.5‰, 5‰) and the porous structure of G/PLGA composite scaffold was formed by using sodium bicarbonate. CCK-8 test, cytoskeleton staining, alkaline phosphatase (ALP) activity test, as well as RT-PCR test were used to detect the cytotoxicity of G/PLGA scaffolds and their effects on the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells (BMSCs). Results：Scanning electron microscopy confirmed the inner connected porous structure of the three-dimensional G/PLGA scaffold as well as the uniform distribution of graphene in the scaffolds. CCK-8 test indicated that G/PLGA porous scaffolds had no obvious cytotoxicity. Compared with BMSCs seeded on PLGA scaffold, the ALP activity of BMSCs seeded on the G/PLGA scaffolds increased and the expression of bone related genes was significantly up-regulated with increase of G concentration. G/PLGA porous scaffold containing 5‰ graphene showed more obvious effects on osteogenic differentiation. Conclusions：The G/PLGA three-dimensional porous scaffold prepared in this research possessed good biocompatibility and could promote osteogenic differentiation of BMSCs in vitro. Thus, it has been expected to be used as a scaffold for bone tissue engineering.

Objective：To research the effect of matrix metalloproteinase 1 (MMP1) overexpression on the osteo/odontogenic differentiation of human stem cells from the apical papilla (SCAPs). Methods： SCAPs were isolated and purified from human third molars with developing roots. Retrovirus expression plasmid PMSCV/MMP1 was constructed. The osteo/odontogenic differentiation capacity was tested by alkaline phosphatase (ALP) activity, alizarin red staining, Western blot assay, and real-time RT-PCR. Results： The ALP activity assay and alizarin red staining showed that ALP activity and mineralization capacity of MMP1 overexpression were decreased. The results of RT-PCR and Western bolt indicated that the mRNA levels of COL1, OCN, RUNX2, OSX and DSPP were downregulated and the protein levels of DSP, RUNX2, OSX and OCN were decreased. Conclusions：MMP1 overexpression downregulates the osteo/odontogenic differentiation potential of stem cells from apical papilla.

Objective：To discuss the effect of 1,25(OH)2D3 in regulation of the level of oxidative stress in temporomandibular joint chondrocyte by constructing the model of 1,25(OH)2D3 deficiency chondrocyte in oxidative stress state. Methods：Knocking down the level of vitamin D receptor in the temporomandibular joint condylar chondrocytes of SD rats by lentivirus infection in order to simulate the 1,25(OH)2D3 deficiency status. Using the exogenous hydrogen peroxide to stimulate both the normal and 1,25(OH)2D3 deficiency chondrocytes we established the oxidative stress model in vitro. Detecting the alteration of oxidative stress level in both groups after being treated with exogenous 1,25(OH)2D3, Malonaldehyde, total superoxide dismutase, Glutathione peroxidase and reactive species oxygen in each group were detected and compared as representing the oxidative stress level in each group. Results：The oxidation level was increased in 1,25(OH)2D3 deficiency chondrocytes after, being treated with hydrogen peroxide. Treated with 1,25(OH)2D3, the level of oxidative stress were decreased obviously in both the normal and 1,25(OH)2D3 deficiency chondrocytes. However the level of oxidative stress in 1,25(OH)2D3 deficiency chondrocytes was still fairly higher than that of the normal group. Conclusions：The deficiency of 1,25(OH)2D3 can increase the level of oxidative stress.

Objective：To investigate the effect of porous TiO2 modified titanium implant prepared by micro-arc oxidation on the adhesion and osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs). Methods：Micro-arc oxidation technology was used to prepare the coating on the pure titanium surface. The surface morphology and crystal phase of the coating were detected by SEM and XRD. After co-culture of material and BMSCs, the expression of adhesion related protein integrin β1 was detected by immunofluorescence staining, in addition, the cytotoxicity of the material was detected by living dead cell staining and MTT. Alkaline phosphatase (ALP) and alizarin red S (ARS) staining assay and RT-PCR were used to evaluate osteogenic differentiation of the BMSCs. Results：The coating of the MAO group treated by micro arc oxidation was microporous TiO2, moreover, the coating not only had no obvious cytotoxicity, but also promoted the expression of integrin β1 in BMSCs. The results showed that both ALP and ARS staining and quantitative of the MAO group was significantly higher than the Ti group which was the untreated group (P<0.05). The results of RT-PCR showed that the expression level of BMSCs ALP and OSX was significantly increased in MAO group over time. Conclusions：The porous TiO2 coating prepared by micro-arc oxidation on pure titanium surface enhanced adhesion and osteogenic differentiation of BMSCs.

Objective：To investigate the effect of lentinan on the proliferation of oral squamous cell carcinoma cell HN4 and its mechanism. Methods：In vitro MTT assay was used to detect the growth inhibition of HN4 cells. The effect of lentinan on the apoptosis of HN4 cells was detected by AO/EB method. The expression of Bcl-2 and Bax in HN4 tumor cells was detected by Western blot . Results：Lentinan could significantly inhibit the growth and proliferation of oral squamous cell carcinoma HN4 cells. AO/EB staining showed that after lentinan stimulated the cells, apoptosis of HN4 cells was observed under a fluorescence microscope, staining increased, nuclear pyknosis and orange-red staining were observed. Western blot results showed that lentinan could decrease the expression of Bcl-2, increase the expression of Bax and increase the ratio of Bax/Bcl-2 in HN4 cells. Conclusions：Lentinan could inhibit the proliferation of oral squamous cell carcinoma HN4 cells in vitro and induce the apoptosis of HN4 cells.

Objective: To evaluatethe clinical effect of Angulated Screw Channel (ASC) abutment in aesthetic area. Methods: Nine cases were selected, which were treated by using ASC abutment designed and made by CAD/CAM in permanent restoration. The application effect of the ASC abutment in the aesthetic area were evaluated by PES, WES, PIS, VAS and other evaluating indicators. Results: The survival rate of the implants was 100% with good osseointegration. The average scores of the red and white aesthetic index indicated by PES and WES were 9.7 and 9.9respectively, while the gingival papilla index indicated by PIS was 2.4.Furthermore, the patient satisfaction survey showed that the patients were satisfied with the final aesthetic effect. Conclusion: The application of ASC abutment can transfer theaccess holein the aesthetic area to the lingual side , and may achieve the screw-retained fixation to replace adhesive-retained fixation,which can help avoiding biological complications due to retention of adhesives and finally achieve ideal aesthetic restoration.

Objective：To evaluate the bond strength of eighth generation adhesive-Single Bond Universal to glass ceramic and resin. Methods: 40 polished and ultrasound cleaned glass ceramics were divided randomly into 4 groups, and followed by different surface treatments: the control without any treatment, silane coupling treatment, hydrofluoric acid etching treatment, and the combination of silane coupling and hydrofluoric acid etching treatment. Each treatment has 10 glass ceramics and covered with Single Bond Universal. Test pieces were made of resin. The test pieces were thermocycled 5000 times and stored in distilled water at 37℃ for 24h before shear bond strength test by universal testing machine. Specimens were also evaluated for mode of fracture using scanning electron microscope (SEM) analysis. Results: The shear bond strength were significantly higher under the hydrofluoric acid etching treatment and the combination treatment than that under the control treatment and the hydrofluoric acid etching treatment, and no statistic difference was found between the hydrofluoric acid etching treatment and the combination treatment. For the mode of fracture, cohesive failure and mixing failure were the main mode under the hydrofluoric acid etching treatment and the combination treatment. Conclusions: When using Single Bond Universal to repair the fracture of the glass ceramic, strong bonding effect will achieve even without silane coupling agent. This might provide the theory basis for the repair of the fractured glass ceramic with resin in clinics.

Objective：To study the change of alveolar bone height and width after tooth extraction by using CBCT. Methods：42 patients with 68 teeth extraction at outpatient department were selected randomly. CBCT was taken preoperatively and 6 months after extraction. The height and width of alveolar ridge before extraction and 6 months later were measured and the width of alveolar ridge were measured at 6 planes, then the absorption of the posterior alveolar bone in the extraction of the posterior teeth was analyzed. Results：Six months after the extraction of the posterior teeth, the alveolar bone height decreased by (1.15±0.46) mm. The alveolar height decreased by (1.83±1.87) mm in the buccal and decreased by (0.99±0.50) mm in the lingual. The average decrease of the male alveolar ridge height was (1.29±0.31) mm, and that of the female alveolar ridge height was (0.69±0.27) mm 6 months after the extraction of the posterior teeth. There were significant difference in the decreased heights of alveolar bone between the buccal and the lingual, male and female. The average decrease of the male alveolar ridge width were (1.93±1.55), (1.34±1.23), (0.98±0.97), (0.45±0.53), (0.19±0.32), (0.06±0.17) mm at 6 planes, respectively.The horizontal absorption of the alveolar ridge in each plane was different . Conclusions： Six months after the extraction of the posterior teeth, the alveolar bone absorbs significantly in the horizontal and vertical, the buccal bone wall absorbs more than the lingual side, and the male absorbs more in the vertical bone than the female. The bone absorption is most at the top of the alveolar ridge, followed by the middle, and basically no absorption at the base.

Streptococcus mutans with the highest detection rate is recognized as one of the most cariogenic bacteria at present.Fluoride is used for the prevention and treatment of caries,which can protect the hard tissues of the teeth and inhibit the growth and metabolism of cariogenic bacteria,such as Streptococcus mutans.Because of the wide application of fluorine, the selective growth of fluoride resistant bacteria has been observed. The research on the mechanism of fluorosis resistance of Streptococcus mutans will help us further understand the generation and development of fluorosis resistance in Streptococcus mutans.In this paper, we summarize the research progress of fluoride transporter EriCF1 and EriCF2, the main mechanism of fluoride resistance in Streptococcus mutans and its fluoride resistant bacteria on the two aspects of protein and gene.The purpose of this review is to provide a direction for the development of new molecular drugs and to provide an important theoretical basis for the prevention and treatment of caries.?