Objective To investigate the effects of small interfering RNA (siRNA) targeting YAP on the proliferationand apoptosis of human periodontal ligament stem cells (hPDLSCs). Methods Synthesized sequences of siRNA were transfectedinto hPDLSCs by LipofectamineTM 2000. The expression of YAP was identified by using real-time quantitative reversetranscription-polymerase chain reaction (RT-PCR) and Western blot analysis. Proliferation activity was detected by usingcell counting kit-8 (CCK-8). Changes in the cell cycle and apoptosis rate were detected by using flow cytometry. Resultswere analyzed by using SPSS 19.0, and P<0.05 was considered statistically significant. Results Expression of YAP mRNAand protein were significantly downregulated after 48 h of transfection (P<0.001). No obvious difference was found in theexpression levels of YAP protein between 48 and 72 h, thus indicating that siRNA could inhibit the expression of YAPpersistently and effectively. Proliferation activity was inhibited, and apoptosis rate was increased. Cell cycle was changedas the proportion of G1 and S phases increased (P<0.01) and G2 phase decreased (P<0.05). Conclusion Knocking down YAP gene by siRNA could inhibit proliferation activity,induce apoptosis, and change the cell cycle of hPDLSCs.Thus, YAP could regulate the proliferation and apoptosisof hPDLSCs.

Objective The effect of advanced glycation end products (AGEs) on the osteogenic differentiation of human periodontal ligament stem cells(hPDLSCs) was discussed. Changes in the Wnt signaling pathway during glycation were also determined. Methods In vitro tissue explanting method was primarily applied. Limiting diluted clone was cultured to obtain hPDLSCs in vitro. The subjects were divided into two groups: the healthy group (N-hPDLSCs) and the AGEs-stimulating group (A-hPDLSCs). Osteoblast mineralization was induced in the experimental groups. The following processes were performed: alizarin red staining; alkaline phosphatase (ALP) staining; real time polymerase chain reaction (real time PCR) for detecting osteogenic genes and Wnt classical pathway-related factors, DKK-1 and β-catenin; Western blot analysis. Bone protein and β-catenin were correlated in the nuclear expression. Results The cells were osteogenically induced. ALP staining showed that the N-hPDLSCs displayed the deepest color. Alizarin red staining indicated that the A-hPDLSCs group had less calcified nodules than the N-hPDLSCs group. The real time PCR results suggested that the expression of relative osteogenic genes in A-hPDLSCs was quite low. Statistically significant differences in differentiation were found between groups (P<0.05). The Western blot result was similar to that of real time PCR. Classical Wnt signaling pathway-related factor β-catenin was higher in A-hPDLSCs than in N-hPDLSCs. By contrast, DKK-1, which is an inhibitor in the Wnt pathway, had a significantly lower expression rate in A-hPDLSCs than in N-hPDLSCs. The Western blot result also showed that β-catenin expression in the nucleoprotein in A-hPDLSCs was notably higher than in N-hPDLSCs. Conclusion AGEs can inhibit hPDLSCs osteogenic differentiation. AGEs induce changes in the normal periodontal ligament stem cells classical Wnt pathway. Canonical Wnt pathway is reactivated because of AGEs stimulation.

Objective Changes in the osteogenesis of diabetic rat bone marrow mesenchymal stem cells (BMSCs) by the regulation of Lnk/stem cell factor (SCF)-cKit signaling were investigated. Methods BMSCs were isolated from diabetic rats and identified by immunocytochemical staining. These cells were divided into the control group (untransfected group), negative control group (transfected with control plasmid), and RNA interference group (transfected with Lnk-targeting RNA interference plasmid). Western blot was performed to analyze the effect of interference. The BMSCs were induced for osteogenic differentiation under diabetic conditions, and Western blot was used to examine the expressions of Lnk, SCF, and cKit in Lnk/SCFcKit signaling and osteogenic proteins alkaline phosphatase (ALP), osteocalcin (OCN), and collagen type Ⅰ a1 (ColIa1). Results Isolated cells expressed CD₄₄ and CD₉₀ but not CD_11b or CD₄₅. This phenomenon was characteristic of BMSCs. Compared with other diabetic BMSCs, cells in the RNA interference group expressed low Lnk but high SCF and cKit (P< 0.05). Thereafter, 28 days after induction of osteogenic differentiation, cells in the RNA interference group expressed low Lnk but high SCF, cKit, ALP, OCN, and ColIa1 compared with other diabetic BMSCs (P<0.05). Conclusion The inhibition of Lnk expression and activation of SCF-cKit pathway may improve the osteogenic differentiation of BMSCs under diabetic conditions.

Objective The effect of sandblasting on the bond strength between 3mol% yttrium-stabilized tetragonal zirconium polycrystal (3Y-TZP) zirconia framework and veneering porcelain was evaluated. Methods A total of 21 specimens [ (25±1) mm× (3±0.1) mm× (0.5±0.05) mm] were prepared according to ISO 9693. The specimens were then randomly divided into 3 groups. Sandblasting was performed on 2 meshes of Al₂O₃ particles: group A with mesh 110 and group B with mesh 80. Group C, which was not sandblasted, was the control group. The surface roughness of the zirconia framework, as well as the bond strength between 3Y-TZP zirconia framework and veneering porcelain, was measured. The interface microstructure was observed by scanning electron microscope (SEM), and elemental distribution was detected by energy dispersive spectroscopy (EDS). Results Surface roughness values were (1.272±0.149) μm for group A, (0.622±0.113) μm for group B, and (0.221±0.065) μm for group C. Statistical significance were found among groups (P<0.05). The bond strength values were (28.21±1.52) MPa for group A, (27.71±1.27) MPa for group B, and (24.87±3.84) MPa for group C. Statistical significance was found between group A and group C (P<0.05), whereas the other groups had no statistical significance (P>0.05). Interface adhesion failure was the primary performance. SEM images showed the close interface bonding, and EDS showed that the interface had no obvious element penetration. Conclusion Al₂O₃ sandblasting can slightly enhance the bond strength between zirconia framework and veneering porcelain.

Objective To evaluate the effect of microwave sintering on the translucency of zirconia and to compare these effect with those of conventional sintering. The relationship between the microstructure of specimens and translucency was investigated. Methods A total of 10 disc-shaped specimens were fabricated from 2 commercial brands of zirconia, namely, Zenostar and Lava. Each group included 5 discs. Conventional sintering was performed according to the manufacturers’ specifications. The maximum temperature for Zenostar was 1 490 ℃, whereas that for Lava was 1 500 ℃. The dwelling time was 2 h. The sintering temperature for microwave sintering was 1 420 ℃, heating rate was 15 ℃·min^-1, and dwelling time was 30 min. After sintering, the translucency parameter (TP) of the specimens were measured with ShadeEye NCC. The sintered density of the specimens was determined by Archimedes’ method. The grain size and microstructure of the specimens were investigated by scanning electron microscopy. Results Density and translucency slightly increased by microwave sintering, but no significant difference was found between microwave and conventional sintering (P>0.05). Small and uniform microstructure were obtained from microwave sintering. The mean TP of Lava was significantly higher than that of Zenostar (P< 0.001). Conclusion The translucency of zirconia sintered by microwave sintering is similar to that of the zirconia sintered by conventional sintering.

Objective To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Methods Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Results Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Conclusion Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

Substantial evidence supports the relationship between chronic inflammation and cancer development. Numerous studies suggest that chronic inflammatory disease, such as periodontitis, contributes to head and neck squamous cell carcinoma development. Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in the oral and maxillofacial regions. Porphyromonas gingivalis, one of the most important pathogens in association with periodontal disease, might have a potential correlation with OSCC. Along with the development of molecular biological techniques, the association between Porphyromonas gingivalis and OSCC has been greatly emphasized in recent years. This review summarizes the association between these variables and the potential mechanisms involved in such relationship.

In recent years, modern tissue engineering is becoming emerging and developing rapidly, and the acquisition, cultivation and differentiation of seed cells is the premise and foundation of the construction of tissue engineering, so more and more scholars pay attention to stem cells as seed cells for tissue engineering construction. Dental pulp stem cells (DPSCs) is a kind of adult stem cells derived from dental pulp, and as a new kind of seed cells of tissue engineering, the study of DPSCs presents important significance in tissue and organ regeneration. In this review, we introduced the progress of studies on dental pulp stem cells and discussed their clinical application prospects.

The keratocystic odontogenic tumor (KCOT) is a common cystic lesions of jaw, which has a high recurrence rate but rarely undergo malignant transformation. This study reported a patient with primary intraosseous squamous cell carcinoma developed from KCOT.

Dermoid cysts in the floor of the mouth with tongue fistula are unusual lesions. This study reported a case of dermoid cyst in the floor of the mouth with tongue fistula, analyzed the causes of such formation, and discussed the appropriate diagnosis and treatment methods by reviewing relevant literature.