Growth activity of osteoblast on a novel strontium incorporated calcium sulfate / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the growth activity of osteoblast on a novel strontium incorporated calcium sulfate and make comparison with normal calcium sulfate material.</p><p><b>METHODS</b>Osteoblast was inoculated on samples and cell proliferation was measured on the 1st, 3rd, 5th days, and the activities of ALP and osteocalcin were observed on the 5th day. And microcosmic morphology of osteoblast was observed by scanning electron microscopy(SEM).</p><p><b>RESULTS</b>Osteoblast grows robustly on tested material. Cell quantity on the surface of novel material was obviously higher than normal calcium sulfate material (P < 0.05). The activity of ALP and osteocalcin on novel material was 57.8% and 40.2% higher than on normal calcium sulfate material respectively (P < 0.05). On strontium incorporated surface, osteoblast spread well. Cells were polygonal with abundant cytoplasm and the morphology was active.</p><p><b>CONCLUSION</b>Strontium incorporated calcium sulfate can sustain robust growth activity of osteoblast, which is promising to be used for bone substitute materials.</p>

Influence of dental restorative material properties on bond interface reliability: a finite element analysis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Varieties of restorative materials are widely used in dentistry. The aim of this study is to explore the influence of different dental restorative materials on bond interface reliability.</p><p><b>METHODS</b>A two-dimensional finite element analysis method was adopted to simulate the shear-bond efficacy test. The influence of elastic modulus and Poisson's ratio were investigated separately. Several dental restorative materials including resins, metals, and ceramics were analyzed in this study.</p><p><b>RESULTS</b>The deformation and peak equivalent stress level of the dentin-adhesive interface rose sharply following a decrease in the elasticity of restorative materials, especially those with a low elastic modulus range. The influence of the Poisson's coefficient was not significant. Ceramics and gold alloy were preferred to resin composite in restorations bearing extensive shear load during service.</p><p><b>CONCLUSIONS</b>Restorative materials with an elastic modulus similar to that of teeth are not always the best clinical choice. This research provides a helpful guide for the application of different restorative materials in clinical practice.</p>

Improvement of osseointegration of titanium dental implant surfaces modified with strontium-substituted hydroxyapatite / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To explore the osteogenic activity of a micro-arc oxidation (MAO)-treated strontium (Sr)-substituted hydroxyapatite (Sr-HA) coating developed to enhance the osseointegration of titanium dental implants, and to investigate the strengthening mechanisms of bone bonding of crystalline hydroxyapatite (HA) with incorporation of strontium in vivo.</p><p><b>METHODS</b>The morphology and phase component of the oxidized film of Sr-HA and HA coated implants were examined by SEM and X-ray diffraction (XRD). Then, twenty-four implants were inserted into the metaphysis of rabbits tibias and femurs using polyfluorochrome sequential labeling. Four and 12 weeks following the surgery, the morphology and chemical composition of the bone-implant interfaces were evaluated by histological examination and energy-dispersive X-ray.</p><p><b>RESULTS</b>The XRD patterns showed that diffraction peaks of HA shift to lower 2θ values with Sr-addition, which resulted in decreases in lattice energy and then crystallinity. Sr-HA coating presented a microporous structure in the SEM observation. Meanwhile, Sr-HA coating exhibited osteogenic activity at the early stage of bone healing period and new bone mineral apposition ratio [(4.75 ± 0.46) microm/d] was significantly higher than that of the control group [(3.21 ± 0.44) microm/d]. An apatite layer was observed at the interface of bone-Sr-HA coating in light microscopy observation and energy-dispersive X-ray analysis. Then the apatite layer was precipitated and formed new bone which became mature bone and bonded tightly to the Sr-HA.</p><p><b>CONCLUSIONS</b>Strontium-substituted hydroxyapatite coating shows high biological activity, which can accelerate the formation of apatite layer, hence the osteogenic ability.</p>

Studying the biocompatibility of implant titanium alloy after surface treatment by sandblasting and etching / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of this study was to investigate the in vitro effect of cell behavior on a new titanium alloy and coarsening surface with sandblasting and duplicate treated by sandblasting and acid etching (SLA), including cell proliferation, morphology as well as alkaline phosphatase expression.</p><p><b>METHODS</b>The cell derived from calvarial bone of neonate and co-cultured with the surface treated titanium alloys in vitro. The samples were treated by mechanical polishing, the sandblasting and the SLA. Cell proliferation on samples for 3 d was examined by MTT assay and cell morphology was observed by scan electron microscope. Alkaline phosphatase activity was measured at 5 d by ALP-special assay.</p><p><b>RESULTS</b>The sandblasting and the SLA surface showed a significant different to smooth surface in the proliferation osteoblasts. The cells were elongated and spread well and having plentiful filopods on the coarse surface. The basal ALP activity indicated that optical density value of osteoblasts was not significant difference between coarse surface and smooth surface.</p><p><b>CONCLUSION</b>The observed effects are attributed to coarsening surface and support the concept that roughness can enhance the differentiation, good morphology and alkaline phosphatase expression of the cells. These results suggest that the good biological performance evaluation of sandblasting and etching surface is merited.</p>