0.05).Conclusion:It suggests that HPDLFs exposured to static magnetic field produced by magnetic attachment have little mutagenic effects on chromosomes and DNA.

0.05). The maximum color differences ( ?E) in the selected firing cycles were 2.279 8 and 1.389 4 for GI Ⅱand Vita In Ceram Alumina groups respectively, the maximum ?E between the two groups was 2.295 6, which fell into the clinically acceptable threshold for color differences. Conclusion: Color stability of all ceramic restorations with GI Ⅱand Vita In Ceram Alumina as substructure can be guaranteed after repeated firing of veneering porcelain up to 10 times.

Objective To explore the relationship between the maxi ll ofacial complexion and age-sex in Han nationality. Methods The maxillofacial skin chroma L*, a* and b* were measured a nd compared in 1462 people aged from 18 to 85 years old in Han nationality, incl uding 682 men and 780 women, by means of Minolta Chroma Meter CR-100. Results Male had the lower L* and b* value and the hig her a* value than those in female. The maxillofacial chroma L* and a* were related to age negatively, and b* was related to age positiv ely. Conclusion The effect of sex and age on color of the maxillofacial skin should be considered while matching colors in construction o f maxillofacial defect.

0.05).Conclusion: Modified RPI clasp with clinically acceptable retentive force and better cosmetic effcts is feasible for clinical application.

?Objective: To study the preparation method of nanometer powder of zirconia, which was used to toughen dental alumina ceramics. Methods: The inorganic precursors at the concentrations of 0.0155 , 0.03, 0.05, 0.1 and 0.28 mol/L were used to prepare zirconia powder via precipitation method. Ammonia water was added into the said solutions to control the pH value at 7.0, 8.5 and 9. The dried precipitation product was then calcined. The prepared zirconia powder were studied by using X ray diffraction (XRD) and scanning electron microscope (SEM). Results: The zirconia powder prepared under the condition of 0.03 0.05 mol/L concentration of inorganic precursors, pH = 8.5, and calcined at 700 ℃ for 2 h was even in size,well dispersed and well micronized. The diameter of the final powder was about 100 nm. Conclusion: With proper preparation condition, weakly agglomerated powder of zirconia in nanometer size can be obtained.

OBJECTIVEThis study aims to evaluate the optical data of the different sites of the cobalt-chrome (Co-Cr) alloy abutments covered by four different all-ceramic crowns and the color difference between the crowns and target tab using a digital dental spectrophotometer.

METHODSTen Co-Cr alloy abutments were made and tried in four different groups of all-ceramic crowns, namely, Procera aluminia, Procera zirconia, Lava zirconia (Lava-Zir), and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic. The color data of the cervical, body, and incisal sites of the samples were recorded and analyzed by dental spectrophotometer. The CIE L*, a*, b* values were again measured after veneering. The color difference between the abutments covered by all-ceramic crowns and A2 dentine shade tab was evaluated.

RESULTSThe L* and b* values of the abutments can be increased by all of the four groups of all-ceramic copings, but a* values were decreased in most groups. A statistical difference was observed among four groups. After being veneered, the L* values of all the copings declined slightly, and the values of a*, b* increased significantly. When compared with A2 dentine shade tab, the ΔE of the crowns was below 4.

CONCLUSIONFour ceramic copings were demonstrated to promote the lightness and hue of the alloy abutments effecttively. Though the colorimetric baseline of these copings was uneven, veneer porcelain can efficiently decrease the color difference between the samples and thee target.

Ceramics ; Chromium Alloys ; Cobalt ; Color ; Colorimetry ; Crowns ; Dental Materials ; Dental Porcelain ; Dental Prosthesis Design ; Humans ; Metal Ceramic Alloys ; Titanium ; Zirconium

Objective To investigate the differences and harmonization of immunoassay systems in detecting CA19-9 and to assess the possibility of mutual recognition in different laboratories.Methods Data were collected and analyzed from External Quality Assessments (EQA) of NCCL(Lots:200811-201215) and ZJCCL(Lots:080309-120211).120 fresh serum with different concentrations of CA19-9 were collected.The CA19-9 results of healthy people were also collected from September 2010 to March 2012.Four kinds of stable immunoassay systems were involved in our research,including Abbott Architect i2000,Beckman UniCel DxI 800,Roche E170 and Siemens ADVIA Centaur XP.The differences among four system groups were calculated with the EQA data.The fresh serum comparisons were also performed following the guideline of CLSI EP9-A2 The 95％ confidence interval of each immunoassay system was calculated.Comparisons were made by scatter diagrams and weighted regression.Results Both EQA of NCCL and ZJCCL showed better correlation coefficients and larger bias (bw ranged from 1.340 to 4.683) than in fresh serum comparisons.Although the correlation coefficients were all unsatisfactory,the bw were all close to 1 in fresh serum comparisons.When the recommended serum concentration of 27 U/ml was used,the biases were Abbott-Roche-6.41％,Beckman-Roche-5.07％,Siemens-Roche 13.15％,Beckman-Abbott 2.46％,Siemens-Abbott 22.52％ and Siemens-Beckman 39.66％,respectively.Differences of 95％ confidence intervals were statistically significant among parts of the immunoassay systems.Conclusions Only in the lower concentration can CA19-9 results be mutual recognized among four different immunoassay systems,there will be larger differences and risks in the higher concentration.

0.05 ). And the fitness values(?m) of the crown of DA9-4 alloy were:the margin gap of the crown 71.3 ?8.34, the shoulder gap 53.4?4.83, the axial wall gap 41.85?8.08, the occlusal lift amount 55.2?9.21.Conclusion:DA9-4 alloy has good fitness and can meet the require of clinic.

OBJECTIVEStandards for determining mandibular position, especially the centric relation (CR), are in controversy because of anatomical, neurophysiological factors and research methods or instrument. The purpose of this study was to reevaluate the reproducibility of centric relation of the patients with severe dental attrition for oral rehabilitation.

METHODSReproducibility of the centric relation of 6 patients with severe occlusal attrition was investigated by using D5A Denar fully adjustable articulator and the Pantronic recording system.

RESULTS1. In supine position, anterior-posterior(AP) displacement of centric relation (CR) was 0.14 mm and superior-inferior(SI) displacements of CR were between 0.11 mm-0.12 mm. 2. In upright position, anterior-posterior displacement of CR was 0.35 mm and superior-inferior changes of CR were between 0.13 mm-0.20 mm.

CONCLUSIONThe CR is the most stable and reproducible position of mandibule in normal stomatological system and is useful as a reference position in occlusal treatment and functional rehabilitation.

Aged ; Centric Relation ; Dental Occlusion, Centric ; Female ; Humans ; Jaw Relation Record ; instrumentation ; Male ; Mandibular Condyle ; physiopathology ; Middle Aged ; Movement ; Reproducibility of Results ; Tooth Attrition ; rehabilitation ; therapy

Objective: To evaluate the effect of pure titanium modified by bioadhesive RGD peptide on the early attachment, growth and proliferation of osteoblasts. Methods: The titanium samples were hydroxylated by alkali/hot water aging and sol-gel layer-by-layer deposition technique. Afterwards, the terminal -NH_2 group was introduced to the titanium surface by organosilane APTMS self-assembled monolayers and the functional group -NH_2 was further reacted with EDC/NHS by which RGD peptides was covalently immobilized to titanium. The efficiency of this bioreactive surface in promoting cell attachment and the competitive inhibition effect of RGD peptide with different concentrations were observed by calculating the amount of osteoblasts attached on the modified titanium. The growth and proliferation were observed by MTT method and scanning electronic microscopy. Results: The cell adhesion percentage of the RGD modified titanium group was much higher than that of the other groups. The RGD peptide solutions with higher concentration had stronger inhibitory impact on the cell adhesion onto the titanium surface. The cell growth, morphology and proliferation on the RGD peptide modified titanium were better than other groups. Conclusion: Bioadhesive peptide can be chemically grafted onto the titanium surface by means of self-assembled monolayers technique. The cells′ biological behaviors on the surface of RGD immobilized titanium are greatly improved in vitro.