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Biomedical subjects

Fu-qiang Zhang

Publications and source records attributed to Fu-qiang Zhang.

At least 37 records · Page 2Linked to original sources
PubMed2005

[The research on 3-D maxillofacial soft tissue reconstruction by spiral CT].

PURPOSE: To evaluate the role of spiral CT in 3-D reconstruction of maxillofacial soft tissues. METHODS: Spiral CT was given to a patient who had his right ear absent. The data was recorded in DICOM format. Digital image was reconstructed on GE advantage workstation in SSD way. RESULTS: Spiral CT can quickly and precisely scan and reconstruct the whole head, the reconstructed images of facial soft tissues and apparatus were very clear, but the site of pupil can not display. CONCLUSION: Except for the pupils, spiral CT is a useful way for maxillo-facial soft tissue reconstruction. It can be widely used in hospitals.

Face↗
PubMed2005

[Design and application of the framework to prevent fracture of the magnetic denture].

PURPOSE: To investigate the methods to prevent magnetic denture from fracture. METHODS: 17 cases were selected and divided into group A and group B. 9 cases in group A only used resin base, 8 cases in group B were strengthened with frameworks. The rates of fracture or fissure in denture base were observed for 5 years, Chi(2) test was used for statistical analysis. RESULTS: In group A, 3 cases were found with damaged base, there was no fracture happened in group B. Chi(2) test showed that there was significant difference between the two groups (P<0.05). CONCLUSION: Frameworks should be designed to improve the strength of the magnetic denture base. It is easy to manufacture and apply with satisfactory clinical effects.

Dental Restoration Failure↗
PubMed2005

[The research on maxillofacial soft tissue reconstruction by 3-D laser scanning].

PURPOSE: To evaluate the role of 3-D laser scanning on reconstruction of maxillofacial soft tissues. METHODS: 3-D laser scan was given to a patient who had his right ear absent and reconstruct the image. RESULTS: 3-D laser scanning can reconstruct facial soft tissue quickly and precisely, but the image of the ear was not very clear. CONCLUSION: In the living, laser scanning can reconstruct all the maxillofacial soft tissues except for the ear. It can be widely used in clinic and research.

Ear↗
PubMed2005

[3-D FEA of the stress state of abutment and its periodontal tissue with three different retention styles in the absence of mandibular anterior teeth].

PURPOSE: To study the stress of the abutment and its periodontal tissue with different designs of retainer (type of retainer, place)in the same situation of dentural defect. METHODS: Based on the 3-D FEA database of RPD, the stress state of the abutment and its periodontal tissue was analyzed to choose the optimal retainer with the same situation of dentural defect. RESULTS: With three different retainer designs, the retainer on the second premolar and the first molar exerted the smallest stress on the abutment and its periodontal tissue, while the retainer on the first premolar and the first molar had the largest stress. CONCLUSION: Analysis for the health condition of abutment and its periodontal tissue is imperative for the selection of different designs of retainers.

Bicuspid↗
PubMed2005

[Comparison of the cytotoxicity in vitro among six types of nano-silver base inorganic antibacterial agents].

OBJECTIVE: To evaluate the biocompatibility of nano-silver base inorganic antibacterial agents and compare the cytotoxicity in vitro among six types of nano-silver base inorganic antibacterial agents. METHODS: FUMAT T200-4, HN300, Novaron, Kangwang, MOD and SR1000 were diluted to different concentrations, such as 100 g/L, 50 g/L, 25 g/L and 12.5 g/L. The cytotoxicity in vitro of these agents on rat's fibroblast was assayed with MTT method. And the grades of cytotoxicity were compared. RESULTS: High concentrations of nano-silver base inorganic antibacterial agents had cytotoxic effects on rat's fibroblasts L-929. As the concentration decreased, the cytotoxicity decreased. No cytotoxic effects were observed at or below the concentration of 25 g/L. FUMAT T200-4, Kongwang and SR1000, with the carrier of phosphate zirconium, had less cytotoxity than the others. CONCLUSIONS: Nano-Silver base inorganic antibacterial agents, such as FUMAT T200-4, Kangwang, SR1000, have good biocompatibility. And they have the possibility of clinical application. The safe concentration of these agents is at or below 25 g/L.

Animals↗
PubMed2004

[The biomechanical research on the different stress distributions between complete and defective dentition].

PURPOSE: To evaluate the stress distribution of crowns under mastication from the biomechanical respect, and observe the physical effects on different teeth through the interproximal contacts. METHODS: A healthy adult skull with both maxilla and mandible was selected, which had normal overbite and overjet, standard occlusal relationship, and tightly contacting with interproximal teeth. After preparation, a 1mm x 1mm strain foil was bonded on every crown. In centric occlusion, 20 kg vertical load was applied on it. The stress value of crown(GPa) was detected by the YJD-17strain gauge. There were three groups: group 1 with complete dentition, group 2 with the first molar missing, and group 3 with missing of right mandibular first molar, lateral incisor and central incisor. RESULTS: The stress value in complete dentition was 3.4641 in second molar, 0.5132 in second premolar, 1.0264 in canine, and 0 in others. In group 2, the stress value was 5.003 in second molar, 1.4113 in second premolar, the values of other teeth equal to that of group 1. In group 3, the stress value was 5.2603 in second molar,1.6679 in second premolar,3.2075 in canine, 0 in first premolar, respectively. CONCLUSION: In complete dentition, the occlusal strength is distributed through the contact area between interproximal teeth, therefore, the stress value of crown is low. However, in the area near the defective dentition, it will be obviously high.

Biomechanical Phenomena↗
PubMed2004

[Stress analysis of the mandible by 3D FEA in normal human being under three loading conditions].

PURPOSE: The condition and character of stress distribution in the mandibular in normal human being during centric, protrusive, laterotrusive occlusion were analysed. METHODS: The three-dimensional finite element model of the mandibular was developed by helica CT scanning and CAD/CAM software, and three-dimensional finite element stress analysis was done by ANSYS software. RESULT: Three-dimensional finite element model of the mandibular was generated. Under these three occlusal conditions, the stress of various regions in the mandible were distributed unequally, and the stress feature was different;while the stress of corresponding region in bilateral mandibular was in symmetric distribution. The stress value of condyle neck, the posterior surface of coronoid process and mandibular angle were high. CONCLUSION: The material properties of mandible were closely correlated to the value of stress. Stress distribution were similar according to the three different loading patterns, but had different effects on TMJ joint. The concentrated areas of stress were in the condyle neck, the posterior surface of coronoid process and mandibular angle.

Finite Element Analysis↗
PubMed2004

[Research and development for the CAD system of maxillofacial prosthesis].

OBJECTIVE: To establish a CAD system of maxillofacial prostheses. METHODS: The maxillofacial prosthesis CAD system, which included mirror technique, boolean operation and use of FreeForm software, was introduced in detail by use of two clinical cases of auricular and orbital prostheses. RESULTS: The CAD system of maxillofacial prosthesis was successfully established. The 3-D digital images of defected sides of two cases were quickly and conveniently obtained, which were symmetrical and harmoniously match to the deficient sides. CONCLUSION: The established CAD technique is a useful system in maxillofacial area. It may be applied in clinic in future.

Computer-Aided Design↗
PubMed2004

[The establishment of the individual model libraries for stomatognathic system].

PURPOSE: To investigate the method of establishing the individual model libraries for stomatognathic system. METHODS: Based on the normal 3D FE models, including the upper jaw, lower jaw and whole dentitions, with the help of the ANSYS5.5, divided, trimmed or re-built these models, created the abnormal stomatognathic system. RESULTS: Established three model libraries in common use, including the alveolar-absorbed-teeth, loosed-teeth, and alveolar-reduced-area, 308 models in all. CONCLUSION: The established models have a satisfied geometric configuration, it will be more suitable for the research and clinic works if uses the individual FE models.

Dentition↗
PubMed2004

[The establishment of 3D-FE model libraries for the elements of the RPD].

PURPOSE: To establish the 3D-FE model libraries for the elements of the RPD. METHODS: Based on the 3D geometric model libraries of the RPD and normal stomatognathic system, using the software, such as Powershape,Pro/E and Ansys5.5, transformed data, trimmed models, or rebuilt it, established many kinds of FE model elements, then combine these elements in the whole model, connected and trimmed, at last created several kinds of FE model libraries. RESULTS: This study established eight kinds of FE model libraries, including the occlusal rests, clasps, bases, artificial teeth, and connectors, etc, nearly two hundreds FE model elements. CONCLUSION: The established models have a satisfied geometric configuration; these elements combined well in the whole model, and can be easily call-in and edit.

Denture, Partial, Removable↗
PubMed2004

[The establishment of 3D-FE model libraries for the elements of FPD].

PURPOSE: To establish the 3D-FE model libraries for the elements of the FPD. METHODS: Based on the 3-D geometric model libraries of the normal stomatognathic system, using the software, such as Powershape,Pro/E and Ansys5.5, the models of abutments,retainers and pontics were created according to the models of natural crowns. The models of connectors were established according to the sutures between the crowns. RESULTS: This study has established the FE model libraries for the elements of the FPD, including the retainers,pontics,and connectors, three kinds of libraries and 82 elements in all. CONCLUSION: The established models have a satisfied geometric configuration; the analysis models can be easily established and edited.

Denture, Partial, Fixed↗
PubMed2004

[Effect of stress distribution of support tissues using hinge extracoronal attachment prostheses].

PURPOSE: The purpose is to discuss the clinical indications of hinge extracoronal attachment. METHODS: In the experiment, the stress distribution in the periodontal support tissue of the abutment was analyzed under different numbers of abutments by EFA. RESULTS: There was no significant effect on the stress distribution in the supporting tissue according to the different numbers of abutments at the central occlusion, and there was an evenly stress distribution in the abutment and alveolar membrane of the area around the missing teeth. CONCLUSIONS: When using the attachment prostheses to restore the type of the second molar distal-extension for the patient, we can use one teeth as abutment. The attachment is suitable for the cases with better condition of the alveolar membrane without high demand of the abutment teeth of the patient.

Dental Stress Analysis↗
PubMed2004

[The experimental study on sol-gel technique of coating titanium].

OBJECTIVE: The aim of this study was to establish sol-gel technique of coating titanium on the surface of Ni-Cr alloy (PFM) in order to enhance corrosion resistance and reduce corrosive rate in oral cavity. METHODS: The sol-gel technique included four steps: (1) pre-treatment; (2) preparation of sol; (3) coating; (4) heat treatment. Elements on the surface of Ni-Cr alloy were analyzed with X-ray photoelectron spectroscopy. RESULTS: After coating Ti, the surface of Ni-Cr alloy looked light golden without particles, blisters and fragments. Besides Ni and Cr, titanium was found on surface of Ni-Cr alloy after coating. With Ar(+) ion carving-corrosion figure, the thickness of titanium was about 20 - 80 microm. CONCLUSION: With sol-gel technique, titanium could be coated on the surface of Ni-Cr alloy.

Chromium Alloys↗
PubMed2003

[Electrochemical corrosion characteristics of Ni-Cr alloy in artificial saliva].

OBJECTIVE: The aim of this study is to determine the electrochemical corrosion characteristics of Ni-Cr alloys in vitro. METHODS: The electrochemical corrosion behavior of Ni-Cr alloys was studied by polarization curves in artificial saliva at 36.5 degrees C (pH = 7.0) to measure the corrosion potential and self-corrosion current density. With X-ray photoelectron spectroscopy, the element content was analyzed. RESULTS: It was found that the dot corrosion voltage of Ni-Cr was -390 mv, and passivation voltage -160 mv. The area of active dissolvation was from -160 mv to -270 mv. The self-corrosion current density is 0.262 micro Acm(-2). From XPS, the content of Ni, Cr, Mo, Fe was increasing gradually, and the content of O, C was decreasing gradually. The content of Ca decreased because Ca existed in the artificial saliva. CONCLUSION: After polarization curve test, Ni-Cr alloy would occur corrosive reaction, and the corrosion product would attach to the surface of the material.

Chromium Alloys↗
PubMed2003

[Using laser scanning to 3-D reconstruct an ear model].

OBJECTIVE: The purpose of the study was to get the ear data from a laser scanning so that a. STL file can be promoted though which a 3-d ear reconstruction can be held. METHODS: A laser scanning manufactured by France was used to get the data of an auricular model, then the data was turned into a. STL file so that a 3-d image of ear was got. RESULTS: The result shows that a 3-d ear reconstructed image can be got quickly and precisely. The digital image shows that the dimension, shape and long axis of the ear is really similar to the ear model. CONCLUSIONS: This study suggests that laser scanning is helpful and effective to get the data of ear. Through this method, it makes it possible to be ready for the technique of rapid prototyping and provide a new, convenient, effective and safe method to auricular prosthesis.

Ear, External↗
PubMed2003

[The effect on anti-acid corrosion resistance of Ni-Cr alloy coating titanium].

OBJECTIVE: The aim of this study was to investigate the variation of the corrosion resistance of Ni-Cr alloy in acid environment before and after coating titanium in vitro. METHODS: 1. Surface treatment using sol-gel technique of coating titanium. The steps were as follows: (1) Pre-treatment: sanding, washing and activation in order to remove the oxidative product; (2) The preparation of sol: some small charged particles produced by the hydrolytic reaction, and formed sol. These particles would congeal into extremely small ones (diameter usually is 5 microns); (3) Coating; (4) Heat treatment: The organism was resolved and volatilizeed at high temperature, and the atoms of Ti were left. These atoms of Ti were very active and could combine firmly with the atoms on the surface awaiting of treatment. 2. CONDITIONS: artificial saliva; pH = 7.0 and pH = 5.6; temperature: 36.5 degrees C 3. Electrochemical test: polarization curve; instrument: ZF-3 poteniostat. RESULTS: Before coating titanium, when pH was 7.0, the electrode potential of Ni-Cr alloy was -160 mV, and the self-corrosion current density was 0.262 microA cm-2; when pH = 5.6, the data were -182 mV and 0.352 microA cm-2, respectively. This result showed that when pH value reduced, the potential and current density descended, too. This indicated that the material was easy to be corroded. After coating titanium, when pH value was 7.0, the potential was -71 mV, the self-corrosion current density was 0.152 microA cm-2; when pH = 5.6, the data were -89 mV and 0.174 microA cm-2. This indicated that the corrosion rate of material descended evidently after coating titanium in acid environment. CONCLUSION: (1) Not only before coating Ti but also after coating, the corrosion resistance of Ni-Cr alloy would descend in acid environment;(2) In acid environment, the corrosion resistance of Ni-Cr alloy after coating titanium was superior to that of the material before coating. So was in neutral environment.

Chromium↗
PubMed2003

[Circulating test and analysis of clasp retention].

OBJECTIVE: To show the trend of the retention change during the circulation of the clasp dislodging and inserting, and to discuss the proper depth of the undercut for a specific clasp. It is also a basic study for the best designing of RPD. METHODS: The Chatillon force measuring instrument was used to record the variation of the retention of Co-Cr alloy casting Akers clasp when they were dislodging from undercuts of different depths (0.25 mm, 0.50 mm, 0.75 mm) on bicuspid and molar. RESULTS: The data was analysed of Correlation and Regression by SPSS 10.0 statistic software. The variations of the retention in the circulation are obvious from the different teeth and different undercut depths. It shows an attenuation trend in circulation (P < 0.01). After 400 times dislodging, in bicuspid group, the retention of the clasp used in 0.50 mm undercut became less than the one used in 0.25 mm undercut. While the retention of the clasp used in 0.75 mm decreases most obviously, it values 0.7670 kg. In molar group, the attenuations of the retention at different depths of undercut are similar, the retentions of the clasp still rank as, from great to less, 0.75 mm, 0.50 mm and 0.25 mm, in the depth of undercut. CONCLUSION: the proper depth of the undercut for bicuspid is 0.25 mm, and 0.50 mm for molar.

Dental Clasps↗