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.

0.05) respectively. Conclusion: The SY 1 silicon elastomer have suitable physical, mechanical and anti ozone aging properties.

Objective: To study the anatomic structure of the nasopalatine duct and the neighboring bone,provide reference for implant surgery in the incisor region. Methods: Manual quantitative measurement of the nasopalatine duct were performed in 73 maxilla specimens (38 from male and 35 from female). Results: The angle between the anterior wall of nasopalatine duct and the nasal floor was 114.80??11.00?, the angle between the cortical plate of anterior maxilla and the nasal floor 107.28??10.75?, the length of the nasopalatine duct was (15.63?2.18) mm in male, and ( 14.59 ?1.96) mm in female, the width of nasal opening of the duct was ( 4.92 ?1.46) mm in male, and (5.73?1.50) mm in female, the width of oral opening of the duct was (3.23?0.60) mm in male and (3.83?0.92) mm in female, at the level of nasal floor, the distance between the anterior wall of the duct and cortical plate of anterior maxilla was (6.15?1.90) mm. Conclusion: In front of nasopalatine duct, implants should be implanted parallel to nasopalatine duct,with an angle about 115? between the implant direction and nasal floor. The bone in front of nasopalatine duct was thin,the diameter of implants applied here should be less than 4 mm.

Objective: To develop titanium posted keeper removable magnetic attachment and to decrease its influence on magnetic resonance imaging(MRI). Methods: Pre fabricated soft magnetic alloy pin cap keeper(PSAPK), casting non precious alloycoping keeper(CNPAK), casting precious alloy coping keeper(CPACK), titanium post keeper(TPK) and titanium post(TP) were prepared and applied on the maxilla of a volunteer, MRI was taken and measured. Results: ①The attachments producing artifacts in MRI from the biggest to the smallest were listed in following rank: PSAPK, CNPAK, CPACK, TPK and TP. ②After removing the keeper from titanium post keeper, the post had no artifact on MRI. ③The artifact was the smallest taken with SE sequence. Conclusion: Titanium post keeper is an effective way to solve the artifact problem and will bring benefits to the patients who need MRI examination of head.

砄bjective:To compare the adherent ability of Candida albicans on the surface of two kinds of silicone elastomer used as prosthodontic materials and to study the factors affecting the adherence.Methods: Candida albicans were cultured on the surface of SY 1 and MDXA 4210 with or without saliva acquired pellicle for 10 min, then the number of the bacteria was counted.Results:With or without saliva acquired pellicle,the number (1?10 3/mm 2) of C.albicans on SY 1 was 24.5?0.88 and 2.0?0.47 respectively( P 0.05 ).Conclusion:There is little difference between the adherent ability of C.albicans on the two kind of silicone elastomer.Saliva acquired pellicle can decrease the adherence.

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.