Research on the microstructure of antibacterial nanocomposite membrane and it's biocompatibility as a guided bone regeneration membrane / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the microstructure of the Ag-nHA-nTiO2/PA66 membrane and investigate its biocompatibility.</p><p><b>METHODS</b>The microstructure of Ag-nHA-nTiO2PA66 membrane and e-polytetra fluoroethylene (e-PTFE) membrane were observed by light microscope and scanning electron microscope(SEM). MG63 osteoblast-like cells were cultured on the two kinds of membrane and blank group. The cell proliferation was checked by methyl thiazolyl tetrazolium (MTT) method and alkaline phosphatase (ALP) activity was detected by enzyme linked immunosorbent assay (ELISA). The adhesion and proliferation of the cells on the two kinds of membrane was observed by SEM.</p><p><b>RESULTS</b>The Ag-nHA-nTiO2/PA66 membrane was composed of the obverse face and the opposite face. The obverse face was porous and the opposite face was smooth. Microstructures of the obverse and the opposite face of the e-PTFE membrane were same. The e-PTFE membrane showed many tiny lined cracks in elliptic structure. MTT assay and ALP measurement showed that there were no significant difference between each of the two membrane groups and the blank (P > 0.05). The adhesion and proliferation of cells on the Ag-nHA-nTiO2/PA66 membrane were better than the e-PTFE membrane.</p><p><b>CONCLUSION</b>Ag-nHA-nTiO2/PA66 membrane has no negative effects on the growth of osteoblast-like cells. Ag-nHA-nTiO/PA66 membrane is biocompatible and its microstructure is appropriate as a guided bone regeneration materials.</p>

The influence of surface conditioning on the shear bond strength of La-Porcelain and titanium / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the influence of different surface conditioning methods on bonding strength of low fusing porcelain (La-Porcelain) and titanium.</p><p><b>METHODS</b>The surface of the samples were sandblasted for 2 min with 80-250 microns Al2O3 or coated for two times with Si-couple agent or conditioned by pre-oxidation. The shear bond strength was examined by push-type shear test with a speed of 0.5 mm/min in a universal testing machine. Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) were employed to explore the relationship between bonding strength and microstructures, as well as the element diffusion at the interface between porcelain coating and titanium when heated at 800 degrees C.</p><p><b>RESULTS</b>Bonding strength was not statistically different (P > 0.05) after sandblasting with Al2O3 in particle size ranged from 80 microns to 250 microns. When a Si-couple agent was used, bond of porcelain to titanium was significantly lower (P < 0.05). The shear bond strength of the porcelain to the pre-oxidized titanium surface remained unchanged after heating (P > 0.05). The SEM results revealed integrity of porcelain and titanium.</p><p><b>CONCLUSION</b>La-Porcelain showed a small effect of surface coarseness. Sandblasting the titanium surface with 150-180 microns Al2O3 can be recommended as a method for better bonding between La-Porcelain and titanium. The Si-couple agent coating and pre-oxidation of titanium surface is unnecessary.</p>