ABSTRACT
Objective:To compare the effects of different polishing techniques on the surface roughness of ceramic surfaces,provi-ding reference to restoration polishing in clinic.Methods:70 disc-shaped ceramic specimens were randomly divided into 7 groups(n=10).The glazing treated samples were served as the controls(group 1),the rest samples were treated by white aluminum oxide stone only(group 2)or followed by the polishing head of Ceramiste(group 3),Ceramiste and Ceramaster(group 4),Komer porcelain (group 5),Komer zirconium oxide(group 6)and EVE zirconium oxide,respectively.Roughness of the ceramic samples(including Ra,Rz and Rp)was measured with surface profilometry after different process and the data were analyzed by one way ANOVA.The surface characteristics of the specimens were observed by scanning electron microscopy.Results:The Ra and Rp of group 2 and 3 was higher than those of group 1(P <0.05).The Rz of group 2,3,4 and 5 was higher than that of group 1(P <0.05).Conclusion:Polishers interspersed with diamond grit may achieve a finish equal in smoothness to the glazed surface.
ABSTRACT
Objective:To assess the effect of accelerated aging on the color and opacity of veneers bonded resin.Methods:28 discs were made with IPS e.max Press A1 shade with the thickness of 0.4 mm.Ceramic discs were divided into 4 groups(n=7). BEAUTIFIL Flow A1 ,DEO-Link SE Transparent,Panavia F Light color and Viriolink N transparent resin cements were applied on the porcelain discs with a thickness of 0.1 mm.Curing was performed with a calibrated LED curing-light for 40 seconds.Color and opac-ity differences of the porcelain substructures after 65 h(150 kJ/m2 )of UV ageing test were examined with a colorimeter.The results were analysed statistically with One-way ANOVA,LSD(L)test.Results:All samples showed significant changes in color and opaci-ty.The ΔE of all materials ranged from 0.6 to 2.29.DEO-Link SE showed the highest color change,while BEAUTIFIL Flow the lowest.The opacity changes ranged from 0.46 to 2.55 and its variation was not significant among groups except for Panavia F.Con-clusion:The accelerated ageing may lead to color changes of ceramic veneer bonded by resins in a clinically acceptable range(ΔE<3).