Translucency and Mechanical Property of Different Translucent Zirconia Thicknesses Compared to Lithium Disilicate Ceramic

Abstract

The purpose of this study was to investigate the effect of thickness on translucency and mechanical property of translucent zirconia compared to lithium disilicate ceramic for proper selection of monolithic crowns. IPS e.max CAD HT and UTML, both shaded A2, were designed and fabricated as circular discshaped specimens (n=30), with a diameter of 12.0 mm, and subdivided into 6 groups: IPS e.max CAD HT and UTML corresponding to thicknesses of 0.8, 1.0, and 1.5 mm (5 discs/group). Their L*a*b values were measured using spectrophotometer, and the TP was calculated. After that, biaxial flexural strength was tested using universal testing machine. Translucency of IPS e.max CAD HT at 1.5 mm was statistically significantly lower than UTML at 0.8 and 1.0 mm (p<0.01). No statistical difference was seen between biaxial flexural strengths of IPS e.max CAD HT at 1.5 mm and UTML at 1.0 mm (p=0.25). According to the indications of manufacturers, fabricating posterior monolithic crown with UTML preserved more of the tooth structure and also provided higher translucency rather than IPS e.max CAD HT, while they were equally strong for such thicknesses.