Research On Optical Properties Of Porcelain Laminate Veneer Using Different Processing Technology To Restore Tetracycline

Objective:To analyze the color properties and translucency of porcelain laminate veneers using different processing technology which used to repaired tetracycline stained teeth,and to provide reference for clinical veneer restoration.Methods:Porcelain specimens with different core and veneer thickness(veneer/core thickness:0.25mm/0.25mm;0.50mm/0.25mm;0.25mm/0.50mm;0.50mm/0.50mm;0.25mm/0.75mm)and different color of veneer(TI 1,dentine A3)were fabricated by heat-press layering technique.Porcelain specimens with different opaque and dentine thicknesses(dentine/opaque:0.40mm/0.10mm;0.30/0.20mm;0.65mm/0.10mm;0.55mm/0.20mm)were fabricated by powder-slurry sintering.CIE L*a*b*parameters were measured under the simulated tetracycline backgrounds and the black and white backgrounds by a spectrophotometer,and color differences between specimens on simulated tetracycline backgrounds and the backgrounds themselves AE001 and between specimens on simulated tetracycline backgrounds and the white background AE002 were calculated.The translucent parameter was also calculated.And then the data were submitted to statistical analysis by SPSS 17.0.Results:In relation to the specimens fabricated by pressing1.When the veneer thickness was same,with increasing of the thickness of the core,?E001 increased and ?E002 decreased.When the core thickness was same,with increasing of the thickness of the veneer,?E001 increased and the ?E002 decreased.There were statistical difference of both ?E001 and?E002 with different core thickness groups(P<0.01).There was interaction between core and veneer thickness.2.The difference of ?E001 and ?E002 were statistically different over different substrates(P<0.01).Color difference ?E002 increased in turn,from yellow?light grey?light red?dark grey to kermesinus.3.?E001 and ?E002 were significantly different over different veneer type(P<0.01).?E002 of dentine A3 was significantly less than TI1.4.As the increase of core or veneer thickness,the translucent parameter decreased.TP was significantly different with different core thickness and veneer thickness.In relation to the specimens fabricated by powder-slurry sintering1.The difference of ?E001 was statistically different over different substrates(P<0.01),but there was no significant difference in ?E002 between different thickness specimens(P>0.01).2.?E001 and ?E002 were significantly different over different veneer type,but there was no significant difference in ?E002 between different thickness specimens(P>0.01).In relation to the processing technology1.With the same total thickness,?E001 of specimens fabricated by powder-slurry sintering was bigger than specimens fabricated by heat-pressing,and ?E002 was less than specimens fabricated by heat-pressing.2.Comparing the same thickness specimens,TPs of specimens fabricated by heat-pressing were significantly bigger than specimens fabricated by powder-slurry sintering.Conclusions:With the limitations of this study,the following conclusions can be drawn:1.The thickness of core and veneer,the color of the substrate and the color of veneer all have significant influence on the color matching and masking ability of porcelain laminate veneers used to repair tetracycline stained teeth.When the veneer thickness is same,with increasing of the core thickness,the masking ability and color matching were increased.When the core thickness is same,with increasing of the veneer thickness,the masking ability and the color matching were increased.About veneer fabricated by pressing,to repair the Yellow tetracycline stained tooth is best in color matching and masking ability;The color matching of veneer with veneer color is A3 was better than that of Tr.the color matching of veneer A3 color cast porcelain is better than that of porcelain decorated with porcelain TI1.2.The porcelain thickness and the color of substrate significantly influence the masking ability of veneer fabricated by powder-slurry sintering.3.In relation to the same thickness,porcelain laminate veneer fabricated by powder-slurry sintering had better masking ability and color matching than veneer fabricated by heat-pressing,while the translucent parameter was opposite.