Objective; To evaluate the reliability and reasonability of maxillofacial skin color match using the digital camera. Methods; The stability of the experimental light source was evaluated before establishing the color measurement. 122 volunteers aged from 22 to 32 years were recorded by a Canon EOS 20D digital camera in studio environment when the light source was stable. Photographs were taken under a set exposure parameters(f/4.5,1/25 s,custom white balance,ISO 800) and saved as JPEG format. The CIE L~* a~* b~* color values were obtained from the digital images using Adobe Photoshop7.0 after color correction. All data were analyzed using SPSS 10. 0. Results;The experimental light source was stable in 21 to 70 minutes. It was suitable for color measurement during this period. The color parameters of all tested maxillofacial skin were:L~*49～66,a~*7 - 18,b~*5 -22. Conclusion;The assessment of maxillofacial skin color depend on method of measurement and instrument. The method of maxillofacial skin color matching by digital camera seems reliable.

0.05).The elongation at break of SY-1 was stronger than that of MDX4-4210 (P

Objective: To evaluate the effect of roughness on adhesive properties of polymethyl methacrylate and SY-1 silicone elastomer.Methods:5 specimens of polymethyl methacrylate were polished by sand paper of different standards and the roughness of polymethyl methacrylate surfaces were measured by roughmeter. The tension strength between polymethyl methacrylate with different degrees of roughness and SY-1 silicone elastomer were tested according to national standards. Results: After the surfaces of polymethyl methacrylate were respectively polished by sand paper of the standard 160,320 and 800, the sufrace roughness decreased, but the tension strength between polymethy1 and SY-1 silicone elastomer was increased(P

Objective:To investigate the three-dimensional accuracy of four impression materials for fixed denture:silicone(OX),hydrocolloid(HT) and two kinds of alginate impression(FC and ZS).Methods:Ten plaster replication models for each impression materials were made on the same metal master cast respectively, vertical and horizontal dimensions between landmarks on the masters and plaster casts were measured with an optical microscope. ANOVA was used to compare the measurements among the materials.Results:The difference between the masters and casts in horizontal distances measured on ZS produced models was bigger than that on other impression material produced ones (P<0.01) and beyond clinical requirment.The difference between the masters and casts in all measured dimensions on OX produced models was the smallest.Conclusion:Alginate paste is not accurate enough for denture model,while silicone is.The hydrocolloid material is relatively accurate.

Objective: To develop a computer-aided three-dimensional design software and laser scanning technique for the restoration of unilateral orbital defect. Method: By laser scanning apparatus plaster face model and the acquired primitive face point data were scanned; with the three-dimensional design software the point data were reconstructed to one smooth face surface image and the data of the defect of the orbital tissue were obtained from the normal contralateral tissue data by software. Results: The face-model data obtained by laser scanning apparatus was distinct and precise; the Digisurf retrograde engineer software succeeded to fulfill the computer-aided design for restoration of unilateral orbital defect. Conclusion: The laser scanning technique and three-dimensional design software can be used in the computer-aided design of the unilateral orbital defect restoration.

Objective:To investigate the stress distribution of the edentulous maxilla with unilateral maxillary defect after implant rehabilitation under occlusal loads.Methods:Three dimensional finite element model of the edentulous maxilla with unilateral maxillary defect was build.The stress distribution of the edentulous maxilla under occlusal loads with computer simulated implant rehabilitation was investigated.Results:Regardless of load manner,the stress of the bone around 1 were high when just healthy side implanted,but the stress reduced after implantantion in health side combined with the implantation in zygoma in defect side.Conclusion:Implantation in health side combined with that in zygoma in defect side can reduce the stress of the bone around the implant.

0.05).Tight integration was found between the two materials in the two groups and there was no distinct interface examined by SEM.Conclusions:GP-084 cellular silicone elastomer and SY-1 silicone elastomer may be adhered completly.

0.05).Conclusion: Feasibility of galvanic corrosion between Fe-16Cr-2Mo soft magnetic alloy and dental alloys used in clinic application can be omitted.

Objective:To study the soft tissue inflammation of percutaneous implants using bacteria investigation method, so as to provide basic data for further clinical study of percutaneous implants. Methods: Implants were surgically placed into tibias of the goats. The inflammatory secretion from the peri-implant soft tissue was taken to perform bacteria test on 4, 6 and 9 weeks post-operation. Meanwhile, the soft tissue inflammatory reaction was also observed weekly. Results: 5 of the 16 implants were infected. The soft tissue showed tumefaction and ulceration 2 months post-surgery. As to bacteria investigation, the number of G.Streptococci increased when the inflammation was getting more severe. Conclusion: The extent of the soft tissue inflammation of percutaneous implants probably has positive correlation with the infection of G.Streptococci.

Objective:To evaluate the effects of surface modified nano titanium-oxide on the mechanical properties of A-2186 silicone elastomers. Methods:Added surface modified nano titanium-oxide into A-2186 silicone elastomers with 0.0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% additions according to the ASTM standard. The mechanical properties of A-2186 silicone elastomer including the tensile strength, the broken elongation, the tear strength and the Shore-A hardness were tested separately. The section of samples were investigated by scanning electron microscope and energy spectrum analysis. Used statistics method to analyse the results. The results were analysed with software EPSS 13.0. Results:With the addition of nano titanium-oxide increasing, the tensile strength, the broken elongation and the tear strength of A-2186 silicone elastomers increased firstly, and then decreased. While the Shore-A hardness of A-2186 silicone elastomers increased gradually. When the addition of surface modified nano titanium-oxide reached to 2.0%, the nano titanium-oxide dispersed well in the base without agglomeration. Under such condition, the A-2186 silicone elastomer showed the best general mechanical properties:the tensile strength was (6.54?0.55) MPa, the broken elongation was 618.00?7.58(%), the tear strength was (16.64?0.52) kN/m and the Shore-A hardness was (31.00?0.79) U. Conclusion:The mechanical properties of A-2186 silicone elastomers are improved most greatly with 2.0% addition of surface modified nano titanium-oxide to the base of A-2186 silicone elastomers.