Three-dimension finite element analyses of interior stress of two kinds of Replace implant / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish three-dimension finite element model of mandible with two kinds of Replace implant, and to study stress of implant and abutment.</p><p><b>METHODS</b>The data of components of the dental implant was measured, cross section of the mandible was scanned by spiral CT and image reconstruction technique was conducted. Three-dimension finite element analysis software UG and MSC. Marc/Mentat were used to built the conjunction model and bone model of two implant systems. Axial loading (200N) and 30 degrees oblique loading (100N) were applied on the models respectively, the stress distribution patterns of the implant and abutment of two implant systems were analyzed.</p><p><b>RESULTS</b>The peak stress district was concentrated on the structure of the implant cervix, which was more obviously displayed on the Replace Select implant. The peak stress of oblique loading was higher than that of axial loading. The peak stress on the implant cervix of Replace Select implant was higher than that of Replace External Hex implant in all loadings.</p><p><b>CONCLUSION</b>To Replace Select especially, oblique force should be avoided on clinical practice in case of the implant fracture.</p>

Construction of a vector expressing SBR gene / 实用口腔医学杂志

Objective: To obtain a prokaryotic expression vector containing saliva binding region (SBR) gene of Streptococcus mutans. Methods: By directional cloning method, SBR gene fragment was cloned into the expression vector pcMVT7, the recombinant plasmid pcMVT7-SBR was transformed to E.coli JM109 (DE3). The gene expression was induced with IPTG. Restriction endonuclease and DNA sequencing techniques were used to identify the recombinant plasmid DNA, and finally target protein was purified by affinity chromatography. Results:The DNA sequence of SBR in the reconstructed vector pcMVT7-SBR was in corresponding with the initial design. The C-terminal 6?His tagged SBR fusion protein was expressed in JM109(DE3) and was purified by affinity chromatography. The expression rate of target protein was 29.73%. Conclusion:The recombinant expression plasmid pcMVT7-SBR was constructed.