ABSTRACT
BACKGROUND:Alveolar bone remodeling and sustained absorption due to tooth extraction seriously affect the implanting conditions and morphology of hard and soft tissue in implant zone. OBJECTIVE:To evaluate the effect of nano-hydroxyapatite/polycaprolactone electrospinning scaffolds to improve the osteogenic effect of bone defects around immediate implants. METHODS:Tissue-engineered bone was prepared by combining canine bone marrow mesenchymal stem cels with nano-hydroxyapatite/polycaprolactone electrospinning scaffold. Bilateral mandibular second premolars from six dogs were extracted mandibular second premolar, and an immediate implant was placed in the mesial fossa of the mandibular second premolar. Three-wal bone defects was made buccaly using titanium nails, then tissue-engineered bone and Bio-Oss bone powders were implanted bilateraly covered by colagen membranes (Bio-Gide). Imageology examination was performed to measure bone gray levels immediately, 4, 8, 12 weeks after surgery. After 12 weeks, the mandible was removed completely, toluidine blue staining was used for observation of microstructure, new bone formation, bone morphology and implant osseointegration. RESULTS AND CONCLUSION: Between the two groups, there was no difference in bone mineral density at each time point after surgery, indicating that the effects of the two materials to promote bone regeneration process are basicaly the same. After implantation, the dense lamelar bone formed in the bone defect region of tissue-engineered bone group, mature bone cels, Haversian canal, and implant osseointegration were visible. While, in the Bio-Oss group, the lamelar bone was dense, a smal amount of Bio-Oss particles distributed within new bone tissues, fewer bone cels were found, a part of Haversian canal was shown to have blood capilaries, and new bone was in close conjunction with the implant. These findings indicate that the nano-hydroxyapatite/polycaprolactone electrospinning scaffold combined with bone marrow mesenchymal stem cels and Bio-Gide colagen membrane can promote the regeneration of alveolar bone around the implant.
ABSTRACT
To study on teaching method to improve the stomatology clinical operation skill,this article summarizes the advantages and disadvantages of multimedia and mutual action applied in stomatology clinical operation.Multimedia is a kind of super-media developing with the progress of computer techniques,and can increase positive study while the teaching method of mutual action can arouse enthusiasm in operation skill training of stomatology clinical skill,thus enhancing the efficiency of studying skill.
ABSTRACT
<p><b>OBJECTIVE</b>The purpose of this study was to investigate the effects of epidermal growth factors (EGFs) with different concentration on the OD, DNA, protein, and PGE2 of A/J mouse embryonic palatal shelves cells (A/J MEPC) isolated from embryonic palatal shelves.</p><p><b>METHODS</b>The mouse embryonic palatal shelves cells were grown in different 39 pores (or bottles) with 9 gradient concentrations of EGF (0.005, 0.010, 0.050, 0.100, 0.500, 1.000, 5.000, 10.000, 50.000 ng/ml), and four pores were prepared for the same concentration, then the OD, DNA, protein and PGE2 of A/J MEPC were measured after 1 day, 3 days and 5 days.</p><p><b>RESULTS</b>EGFs stimulated DNA and PGE2 synthesis of A/J MEPC, and augmented proliferation index (PIX). Their effects were very obvious in promoting the proliferation of A/J MEPC, when the concentration was 10.000 ng/ml.</p><p><b>CONCLUSION</b>EGF may be important in regulating proliferation and metabolism of embryonic palatal shelves cells.</p>