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Objective To execute geometric calibration and calibration phantom design to realize high-quality cone-beam Micro-CT image reconstruction. Methods The geometrical position parameters of cone-beam Micro-CT system were deduced by the data of the designed phantom projected on the detector by means of linear fitting and geometric relation,so as to realize the geometric calibration of the system.The calculation software and the simulation experiment were achieved by VC++programming language.Results The validity and feasibility of the calibration model and method were proved by the experimental simulation. Conclusion The geometric calibration method can accurately calculate the geometrical position parameter errors of the cone-beam Micro-CT system.It can effectively reduce the artifacts in the reconstructed image and further improve the imaging resolution by adjusting the geometric position parameters.[Chinese Medical Equipment Jour-nal,2018,39(5):29-34]
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Objective To explore the methods for suppressing the interferences during the application of medical electronic devices.Methods Kinds of signal sources interfering medical electronic devices were analyzed,and the suppression methods were discussed from the aspects of shielding protection,selection of ground point,filtering,circuit design and etc.Results Interference suppression could be executed by proper grounding,shielding protection,component protection and etc.Conclusion Suppression methods have to be selected according to inference source during the clinical application of medical electronic devices.
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<p><b>OBJECTIVE</b>To evaluate the clinical behavior of zirconia restorations fabricated by computer aided design and computer aided manufacture (CAD-CAM) system.</p><p><b>METHODS</b>One hundred and thirteen patients with 167 unit restorations were enrolled in the study. First, the shape of abutment teeth and occlusion record was captured and digitized by Sirona inEos system. Then, each individually shaped framework was created using the cut-back program of inLab V3.85 software to leave a uniform thickness to the ceramic veneer. All restorations were veneered with Vita-VM9 and evaluated at baseline, 6, 12 months after delivery using the modified U S Public Health Service Criteria (USPHS).</p><p><b>RESULTS</b>During the 6 to 12 months' follow-up visit, the success rate of the restorations was 96.1% (147/153), none was replaced due to framework fracture or unrestorable delamination of the ceramic veneer, and all patients were satisfied with the shape and color of their restorations.</p><p><b>CONCLUSIONS</b>Based on the results of this study, it can be concluded that zirconia frameworks demonstrated sufficient stability for all-ceramic fixed partial denture using individual-design processing technology.</p>
Subject(s)
Humans , Ceramics , Computer-Aided Design , Crowns , Dental Abutments , Dental Materials , Dental Porcelain , Dental Restoration Failure , Denture, Partial, Fixed , ZirconiumABSTRACT
<p><b>OBJECTIVE</b>To study the biocompatibility of Ti-24Nb-4Zr-7.9Sn (TNZS) ahoy treated with micro-arc oxidation (MAO).</p><p><b>METHODS</b>The tibia bones of New Zealand rabbits were used to build the animal model. TNZS and MAO-TNZS samples were implanted into one side of tibia, pure titanium samples were implanted into the other side as control. After 4 and 26 weeks, radiographs and HE staining technique was used to observe the dynamic remodeling process of bone-implant interface.</p><p><b>RESULTS</b>As the cure time increased, it was showed well biocompatibility of all implants. X-ray indicated that there was no permeable area produced around the three different materials at each time point. The density of bone matrix and arrangement of bone trabecula was almost the same as in the host bone. It was revealed by histological examination that the MAO-TNZS greatly prompted the bonding ability between implant and surrounding hard tissues. Four weeks after implantation, fine attachment was found at the bone-implant interface of all the implants and the fibrous tissue at the interface was gradually remodeled to form new bone. Twenty-six weeks later, MAO-TNZS showed that a biological fixation was created between bone and oxidation layer, while a layer of fibers formed between non-coated TNZS and titanium implants surrounding bone.</p><p><b>CONCLUSION</b>The Ti-24Nb-4Zr-7.9Sn after treated with micro-arc oxidation shows good biocompatibility and can stimulate the bone growth in the bone-implant region, which provides support for clinical usage tests of TNZS alloy as implant after treated with micro-arc oxidation.</p>