Diagonal root separation method for extracting impacted double-root mandibular third molars / 华西口腔医学杂志

Double-root mandibular third molars are the common types of mandibular third molars that are prone to impac-tion. Based on the summary of clinical cases and experience, the commonly used crown-root separation technique is improved as diagonal root separation technique that divides the roots by the line connecting the distal axis angle to the root furcation. This new method improves the efficiency of the operation and reduces surgical trauma. This paper details the surgical method, minimally invasive mechanics, and key points of this technique, compares the technique with the crown-root separation tech-nique, and discusses their joint applications.

Negative pressure promotes epidermal differentiation of bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND: As a physical factor, negative pressure can promote the osteogenic differentiation and endothelial differentiation of mesenchymal stem cells. If a negative pressure exerts effects on the epidermal differentiation of mesenchymal stem cells, it will be highly important for the combination use of negative pressure and mesenchymal stem cells in wound healing. OBJECTIVE: To explore the effect of negative pressure on the epidermal differentiation of bone marrow mesenchymal stem cells. METHODS: Bone marrow mesenchymal stem cells of New Zealand white rabbits were isolated and cultured. Then, the passage 3 cells were induced for epidermal differentiation under negative pressure (-16.625 kPA, twice a day, once for 4 hours) as experimental group. Another cells induced under no negative pressure were used as control group. After induction, cell growth curve was drawn in each group, and the expression of cytokeratin 5 and cytokeratin 10 mRNA was examined by real-time PCR at 2 weeks after induction. RESULTS AND CONCLUSION: The cell growth of the experimental group was inhibited, and the mRNA expression of cytokeratin 5 and cytokeratin 10 was significantly increased compared with the control group (P < 0.05). These findings indicate that under the condition of negative pressures, the epidermal differentiation ability of bone marrow mesenchymal stem cells is increased, and in contrary, the cell proliferation is inhibited.