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 test the reliability of 3 dimentional (3D) laser surface scanner for nasal anthropometry.Methods:11 plaster nasal models were measured by 3D laser surface scanner and manual measurement. The data were statistically analyzed. Results:In 9 out of the 10 parameters of nasal anthropometry,the correlation coefficient of the distances and angels measured by the 2 means was 0.856-1.000(P

Objective To test the performance of the field digital oral medical vehicles(two chairs) developed by School of Stomatology,the Fourth Military Medical University.Methods The field digital oral medical vehicle was developed by using dental health care system,diagnostic imaging systems,oral endoscopic systems,infection control systems,digital management system,the sewage treatment system,temperature conditioning systems,power generation systems,automotive GPS positioning system and other systems.Results The vehicle was characteristized by reliable performance,high degree of functional serialization,complete medical facilities and good operability of the internal layout.Conclusion Its functions fully meet the requirements in field oral disease prevention and control as well as first aid.

Objective: To explore the possibility to restore alveolar process cleft and the defects of front maxillae with telescope techniques. Methods: 4-5 telescopes were used as retainers of a prosthesis for cleft alveloar process or the defects of front maxillae; metal framework was used as connector of abutments and obturator in soft-tissue defect. Porcelain or resinmetal crowns were applied to restore defects in dentition. Acrylic resin was applied to repairs the deftcts of alveolar process and front maxillae or defect of palate. By above ways, prostheses were fabricated, the patients were followed up. Results:The following up for 26-28 months in 6 cases showed that the prosthesis retained with telescopes had follow advantages: good retention, convenient application, high masticatary function and satisfactory esthetics effects. Conclusion:The prosthesis with telescopes is feasible for the restoration of cleft alveolar process and the defects of front maxillae.

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.