With the maintenance, purchase and utilization analyzed, the medical engineer is oriented to enhancing the efficiency of the hospital and strengthening the construction of medical engineering department.

Objective: To investigate the effect of Wnt3a on osteogenic differentiation of human dental pulp stem cells (DPSC). Methods: DPSCs were subjected to different concentrations of Wnt3a (0, 5, 20, 50 and 100 μg/L) and at seven days after culture the alkaline phosphatase (ALP) activity was tested. Mineralized nodule formation was examined by alizarin red staining. Osteogenic-related gene expression of bone sialoprotein (BSP), osteocalcin (OCN), collagen type Ⅰ (COL-Ⅰ), Runt-related transcription factor-2 (RUNX2) was examined by quantitative real-time PCR (qPCR). Results: After seven days of induction by DPSC, Wnt3a protein could inhibit the ALP activity (concentration 0: 1.076±0.203, 5 μg/L: 0.828±0.118, 20 μg/L: 0.505±0.044, 50 μg/L: 0.499±0.038, 100 μg/L: 0.483±0.060). The expression of OCN in 5 μg/L Wnt3a group (0.092±0.005) was lower than that in culture medium (0.858±0.190)(P<0.05). Alizarin red staining showed that 5 μg/L Wnt3a had no mineralization induction effect on DPSC. Conclusions Wnt3a could inhibit osteogenic differentiation of dental pulp stem cells.

Objective: Investigate osteogenic differentiation of canine periodontal ligament stem cells ( cPDLSCs) via over-expression ephrinB2 in cPDLSCs． Methods : cPDLSCs were isolated from the premolars and molars of Beagle．After transfected with EfnB2-GFP-Bsd and GFP-Bsd empty Vector，cPDLSCs were induced to osteogenic differentiation．Western blot was used to invest the expression of ephrinB2 protein．The effect of osteogenic differentiation of EfnB2-cPDLSCs and Vector-cPDLSCs were analyzed by RT-PCR , CCK-8，Alizarin-red S staining and ALP. Results: There was no significant difference in cell proliferation between EfnB2-cPDLSCs and Vector-cPDLSCs．While EfnB2-cPDLSCs displayed an enhanced ALP activity and more prominent mineralized nodules compared with Vector-cPDLSCs．The odonto-/ osteogenic genes in EfnB2-cPDLSCs were also highly enhanced． Conclusion The results of our study indicated that ephrinB2 gene-transfected cPDLSCs showed enhanced osteogenic differentiation.

Objective : To measure the anatomical parameters of the first maxillary molars in children of different age groups and evaluate the age⁃related changes in dental crowns. Methods : A retrospective analysis was conducted on cone beam computed tomography (CBCT) images of 4⁃8 ⁃year⁃old children. NNT software was used to analyze multiple important indicators of maxillary first molar. Results : A total of 308 first maxillary molars , including 154 pediatric patients , were evaluated in this study. The thickness of the pulp apex H1 (left , P = 0. 01 ; right , P = 0. 02) and the thickness of the pulp chamber floor H3 (left and right P < 0. 01) were positively correlated with age , while the height of the pulp cavity H2 (left and right P < 0. 01) and the height of the palate tip D1 (left P = 0. 003 , right P = 0. 002) showed a negative correlation with age. There was no significant correlation between the height of the buccal tip and age (P > 0. 05) . There were significant differences in H1 and H3 between the 4⁃year⁃old and 5 ⁃year⁃old age groups between the 8 ⁃year⁃old age group ( P < 0. 05) , as well as significant differences in H2 and D1 between the 4⁃year⁃old and 5 ⁃year⁃old between the 6⁃year⁃old , 7 ⁃year⁃old and 8 ⁃year⁃old age groups (P < 0. 05) . Conclusion The age⁃related changes in the crowns of the first maxillary molars are important references for the clinical treatment , and can be accurately measured through CBCT data.