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 explore the clinical application of reconstructing silicone elastomer nose prosthesis by means of selected laser sintering and wax powder PCPI. Methods Laser scanning was used to get the 3-D data of a nose model. Surfacere 10.0 etc softwares was used to reconstruct the nose by mirroring the digitalized model of absent nose. Selective laser sintering and wax powder was chosen to fabricate a wax nose model and the nose prosthesis made by silicone clastomer. Results Perfect silicone clastomer nose prosthesis was made for 2 patients. Conclusion This study suggests that the wax nose model and the new wax powder can meet the requirement of clinical expectation for maxillofacial prosthesis.

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 investigate the effects of enamel matrix pr ot eins(EMPs) and purified EMPs(EMD) on the proliferation and protein synthesis act ivity of rat ectomesenchymal stem cells in vitro. Methods: C ell culture technique and 3H-leucine label assay were used to measure the pr oliferation and protein synthesis activity of rat ectomesenchymal stem cells exp osed to the EMPs- or EMD-conditioned culture media with different concentratio n. Results: Both EMPs and EMD at 50～200 mg/ml increased the pro l iferation and protein synthesis of the cells in 10-day-culture. EMPs and EMD a t 150 mg/ml showed the strongest effects(P

Objective:To reconstruct a 3-D wax nose model and make a s ilicone elastomer nose prosthesis. Methods:Laser scanning was us ed to get the data of a nose model, selective laser sintering and wax powder wer e used to fabricate a wax nose model,the nose prosthesis was made by silicone el astomer. The differences in length(L),width(W),deepth(D),height(H) and tip-angl e(TA) among the nose models made with plaster, wax powder and silicone elastomer were compared. Results:L(mm) in plaster, wax and silicon e models was 36.61,36.60 and 36.60 respectively.W(mm),D(mm),H(mm) and TA(?) in the three kinds of models were the same:36.23,18.45,43.14 and 74.57 respectively .Conclusion:Nose model made of the wax powder is precise and can meet the requirements for maxillofacial prosthesis.

Objective:To study the feasibility of repair of partial maxillary defect by distraction osteogenesis(DO) in zygoma.Methods:Segmental maxilla- zygoma defect was made in 3 dogs. A submerged DO distractor was anchoraged on the zygoma and maxilla across the defect,the zygoma was distracted with a rate of 1.0 mm/d for ten days,the process of bone formation was examined by X-ray.Results:All dogs were in health condition within the experimental period.New bone formation was observed 2~4 weeks after operation. Complete repair of the defects was observed 8 weeks after the completion of distraction.Conclusion:The partial maxillary defect may be repaired by DO in zygoma.

Objactive:To study the color changes of SY-1 silicone elastomer before and after polymerization.Methods:L*a*b*color parameters of 10 samples of SY-1 silicone elastomer were measured with Minolta chroma-ticity instrument(CS-321) before and after polymerization.The color difference(△E) between precure and post-cure was calculated as△E =[(△L)2+(△a)2+(△b)2]1/2.Results:After polymerization L*and a*valueswere increased(P