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1.
Chinese Journal of Stomatology ; (12): 378-382, 2015.
Article in Chinese | WPRIM | ID: wpr-294699

ABSTRACT

<p><b>OBJECTIVE</b>To develop novel polyetheretherketone (PEEK) based nanocomposites which possess the favorable antibacterial property, and to investigate the oral microbial adhesion and biofilm formation on the surfaces of PEEK, nano-fluorohydroxyapatite (n-FHA)-PEEK and nano-hydroxyaptite (n-HA)-PEEK.</p><p><b>METHODS</b>The bacterial adhesion and biofilm formation on the surfaces of n-FHA-PEEK, n-HA-PEEK were investigated via microbial viability assay kit and laser scanning confocal microscope (LSCM), respectively, with pure PEEK as control group.</p><p><b>RESULTS</b>No significantly statistical difference were found in the bacterial adhesion amounts on the surfaces of n-FHA-PEEK, n-HA-PEEK and PEEK at 1 h and 4 h. However, the number of bacteria on the n-FHA-PEEK surface decreased dramatically at 2 h (0.496 ± 0.008) compared with n-HA-PEEK groups (0.543 ± 0.015, P < 0.01). Although the biofilms formation on surfaces observed by LSCM had similar morphology and thickness at 3, 7, 14 d, that on the n-FHA-PEEK surface showed the highest dead-to-live bacteria ratio among the three materials at 14 d.</p><p><b>CONCLUSIONS</b>The combination of n-HA, especially for the n-FHA could inhibit the bacteria adhesion and accelerate the bacterial death, eventually may have an influence on the structure of biofilms and reduce the risk of peri-implantitis. Therefore, n-FHA-PEEK nanocomposites presented a good prospect for clinical applications as dental implant materials.</p>


Subject(s)
Bacterial Adhesion , Physiology , Bacterial Load , Biofilms , Dental Implants , Microbiology , Hydroxyapatites , Ketones , Nanocomposites , Microbiology , Polyethylene Glycols
2.
Journal of Practical Stomatology ; (6): 161-164, 2014.
Article in Chinese | WPRIM | ID: wpr-445220

ABSTRACT

Objective:To evaluate the influence of cervical collar height on the compressive strength of CAD/CAMzirconia-ceramic restoration.Methods:Zirconia cores were manufactured and divided into 5 groups (n =1 0)based on the cervical collar height(mm):0.0(A),1 .0(B),1 .5(C),2.0(D)and 2.5(E).After veneered with porcelain,all the samples were cemented on the metal tooth analog and then mounted in an universal test machine.The force was applied at a crosshead speed of 1 mm/min until catastrophic fail-ure occurred.Fracture loads and failure modes were recorded.Results:Mean of the fracture strength values(kN)in group A,B,C, D and E were 0.95 ±0.39,1 .29 ±0.50,1 .54 ±0.28,2.04 ±0.1 9 and 2.27 ±0.53 respectively(among groups,P <0.05).Two types of fracture modes were observed:chipping of the veneering porcelain and fracture of the veneering porcelain together with the framework.Conclusion:Zirconia coping design with 1 .5 mm cervical collar height may increase the compressive strength of CAD/CAMzirconia-ceramic restoration.

3.
Chinese Journal of Tissue Engineering Research ; (53)2007.
Article in Chinese | WPRIM | ID: wpr-588568

ABSTRACT

AIM: To explore the feasibility of bone tissue regeneration guidance with the frozen heterogeneous periosteum. METHODS: The experiment was conducted in the animal laboratory of Beijing Shijitan Hospital from March to December 2002. ①Preparation of the frozen heterogeneous periosteum: The fresh pigs' cranial or rib bone periosteum was taken and washed with saline solution repeatedly, then defatted by immersion in 0.75 volume fraction alcohol, followed by frozen in the liquor of nitrogen for 10 minutes repeatedly for 3 times. After irradiated under ?-ray up to the amount of 3 kGy, the created membrane was placed in refrigerator for using. ②Surgical procedure: Two artificial mandibular bone defects were performed in 30 adult Japanese white big ear rabbits. One defect was covered with the created membrane as the experimental group, while another as the control group. ③Index observation: The rabbits were sacrificed after 2, 4, 8, 12, 16 weeks postoperatively for macroscopic, radiographic and histopathological observation. RESULTS: All 30 rabbits were involved in the result analysis. ①Macroscopic examination of the two groups: At the eighth week, guiding membrane was observed with irregular border. The experiment group was flat and stiff, while the control group was restored but with soft bone; at the twelfth week, the guiding membrane and surrounding border were unclear, but still could be observed. The newly bone of the experiment group was flat and stiff, while the control group was soft with hollow. ②Histopathological examination: At the eighth week, the new-formed bone in the margin of defect area of the experimental group grew intensively and the inflammatory cells in grafted membrane disappeared; intramembrane fiber was found oedema and broken; at the twelfth week, the trabecular bone of the experimental group was thick and arranged regularly. However, in the control group, the newly formed bone was little in the defect, and the trabecular bone was thinner compared with the experimental group. No evidence of inflammatory reactions was apparent, meanwhile the membrane degraded gradually. ③Radiograph examination: The bone density of the experimental group was greater than the control group at 4 and 8 weeks, and had no significant difference as to the vicinity bone at 12 and 16 weeks; on the other hand, the density of the control group was still lower. CONCLUSION: The frozen heterogeneous periosteum is a useful guiding membrane material for tissue regeneration, because it has no obvious rejection action in body, and could maintain its shape for 8-12 weeks, prevent the fiber tissue from growing into the wound surface, separate different cells and guide tissue regeneration.

4.
Journal of Peking University(Health Sciences) ; (6)2003.
Article in Chinese | WPRIM | ID: wpr-560136

ABSTRACT

Objective: To evaluate the biocompatibility of polymethylmethacrylate(PMMA) denture base resin containing silver-supported antimicrobial agent STR-1 of nanometer level in vitro. Methods: According to the national standards for biological evaluation of dental materials, the cytotoxicity of denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was examined by molecular filtrating method, and the hemolysis of STR-1, denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was also surveyed. Results: The control denture base resin without containing STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were not cytotoxic to L929 cells. Two hours and 24 hours after cell culturing, the filter membranes of the control and experimental groups were stained evenly with blue color. The staining intensity was not decreased and the fading areas were 0 mm~2 during the culturing. The cytotoxicity grades were 0. The hemolysis rates of the antimicrobial agent STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were 1.7%, 3.5% and 3.7% respectively. They were less than the national guild standard 5% which represent no hemolysis. Conclusion: The PMMA denture base resins containing silver-supported antimicrobial agents STR-1 of nanometer level at concentrations of 5 g/L and 10 g/L exhibit good biocompatibility.

5.
Journal of Practical Radiology ; (12)2001.
Article in Chinese | WPRIM | ID: wpr-541758

ABSTRACT

Objective To assess the clinical application of STIR sequences in the diagnosis of traumanic marrow edema. Methods Twenty-eight cases of traumanic marrow edema were found on MRI exam. Except routine SE T1WI?FSE T2WI and GE T2*WI, STIR sequence was performed.Results Thirty-six bone marrow edema were found in 28 cases, 24 lesions(67%)were all hypointensity on T1WI,12 lesions(33%)were depicted on T2WI, 8 lesions presented hypointensity and 4 mild hyperintensity. 29 lesions(80%)on T2*WI,14 were hypointensity and 15 hyperintensity. With STIR, 36 lesions(100%) displayed as hyperintensity signal more clearly.Conclusion STIR is good delineating traumanic marrow edema.

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