Biological characterization and in vitro biocompatibility of human placenta derived mesenchymal stem cells / 中国组织工程研究

BACKGROUND:At present bone marrow mesenchymal stem cel s act as the main seed cel s in bone tissue engineering, but only 0.001%-0.01%cel s are in the bone with difficulty in cel separation and purification. OBJECTIVE:To explore the biological characterization of human placenta derived mesenchymal stem cel s and biocompatibility with three-dimensional porous hydroxyapatite ceramic scaffold. METHODS:Human placenta derived mesenchymal stem cel s were morphological y observed and identified usingflow cytometry, fol owed by osteogenic, adipogenic, chondrogenic induction for 3 weeks. Afterwards, the potential of multi-directional differentiation was identified by alizarin red S, oil red O and toluidine blue staining. DAPI staining was used to observe the adhesion of cel s on the surface of the hydroxyapatite ceramic scaffold under scanning electron microscope. RESULTS AND CONCLUSION:The human placenta derived mesenchymal stem cel s showed long spindle shape and uniform size under the microscope;they highly expressed CD29 and D90, but did not express CD45 and CD106. Fol owing induction, mineralized nodules were observed by alizarin red S staining, lipid droplets by oil red O staining and blue-dyed toluidine blue staining. These cel s adhered wel to the scaffold surface, indicting they are suitable for bone tissue engineering.

Differential proteomics on synthetic antimicrobial decapeptide against Streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the protein profiles between decapeptide-treated and untreated planktonic cells of Streptococcus mutans (S. mutans) by differential proteomic analysis to determine and identify the key proteins.</p><p><b>METHODS</b>In our previous study, we investigated decapeptide (KKVVFKVKFK-NH2), which was a novel adenosine monophosphate. Compared with other oral pathogens tested, decapeptide had a preferential antibacterial activity against S. mutans. It also inhibited S. mutans biofilm formation and reduced the one-day developed biofilm. In the present study, we first synthesized decapeptide, and then compared the protein profiles between decapeptide-treated and untreated planktonic cells of S. mutans by two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. We also verified different expressions of key protein enolase in the protein level.</p><p><b>RESULTS</b>The results showed that decapeptide altered the protein expression of planktonic S. mutans. These proteins were functionally involved in carbohydrate degradation by glycolysis, protein folding, conjunction, transport, translation, adenosine triphosphate binding, protein binding, sequence-specific DNA binding, transcription factor activity, and two-component response regulator activity. Western blot results showed that enolase protein expression decreased obviously in decapeptide-treated cells of S. mutans.</p><p><b>CONCLUSION</b>The protein expression of S. mutans significantly changed after synthetic antimicrobial decapeptide treatment, suggesting that decapeptide may present a preferential effect on oral caries by changing the expression of certain key proteins, such as enolase protein.</p>

Three-dimensional finite element stress analysis of mandibular unilateral distal-extension with extra-coronal precision attachment / 生物医学工程学杂志

From alveolar bone and the complete dentition CT images, a three-dimensionalysis of nonlinear finite element model of mandibular unilateral distal-extension with extracoronal precision attachment was established. The contact elements were used between the denture and alveolar bone. The result shows that, the stress in the second premolar and periodontal tissue decreased obviously as the second abutment was added. However, the stress difference was unapparent as the third abutment was added. Considering various facts, the attachment with two abutments was suggested to be used. With the decrease of the periodontal tissue, the stress in the periodontal tissue increased, however the stress in the tooth changed slightly. Thestress in the periodontal tissue decreased effectively when the third abutment was added, as the tooth root was absorbed by 50%. In this situation, the extracoronal precision attachment can also be used.

The 3D finite element analysis of stress distributions in abutment and periodontal tissues with extra-coronal attachment / 生物医学工程学杂志

A 3D finite element model of bilateral distal-extension edentulous dentition, which includes mandible, incisors, canines and premolars, was established in the first place. Based on it, another model with extra-coronal attachments and dentures was also developed. Moreover, contact elements were applied to the regions between the denture and alveolar bone. The von Mises stress distributions of the abutments and their periodontal tissues, edentulous alveolar bone in the two models were compared. The results indicate that the stresses in the abutments and the alveolar sockets obviously increase at the buccal and lingual sides after reparation, and that the stresses on the edentulous alveolar bone also increase.

The evaluation of color for the clinical application of thinner porcelain laminate restoration / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of this study was to evaluate the clinical application of the thinner porcelain laminate restoration, which is initiated in the West China College of Stomatology, Sichuan University.</p><p><b>METHODS</b>The color of 51 ceramic veneers was evaluated using the chromatic instrument and visual observation.</p><p><b>RESULTS</b>Among factors affecting the clinical results of the porcelain laminate, the hue of ceramic materials and bond composites played a more important role than the dentition. The brightness of ceramic materials and bond composites were closely correlated with the whole restoration brightness. There was also a close correlation between the brightness and the bond composite.</p><p><b>CONCLUSION</b>Satisfactory restoration results can be achieved by clinical application of thinner porcelain laminate.</p>

Relationship between maxillofacial complexion and age-sex in Han nationality / 中华医学美学美容杂志

Objective To explore the relationship between the maxi ll ofacial complexion and age-sex in Han nationality. Methods The maxillofacial skin chroma L*, a* and b* were measured a nd compared in 1462 people aged from 18 to 85 years old in Han nationality, incl uding 682 men and 780 women, by means of Minolta Chroma Meter CR-100. Results Male had the lower L* and b* value and the hig her a* value than those in female. The maxillofacial chroma L* and a* were related to age negatively, and b* was related to age positiv ely. Conclusion The effect of sex and age on color of the maxillofacial skin should be considered while matching colors in construction o f maxillofacial defect.