Effect of Veneering Ceramic Thickness on Fracture Strength of All-Ceramic Lithium Disilicate Restorations
Author(s): Ezzatolah Jalalian, Mostafa Heidari, Mobina Aminimanesh, Chakameh Rezaei
Fracture strength is an important factor affecting the survival and clinical service of all-ceramic restorations. This study aimed to assess the effect of veneering ceramic thickness on fracture strength of all-ceramic restorations. Thirty lithium disilicate discs (IPS e.max Press) with 10 mm diameter and 0.5 mm thickness were fabricated to serve as restoration core. They were placed at the bottom of the mold and porcelain was applied on top of them in 0.5, 1 and 1.5 mm thickness. They were then subjected to thermocycling and cyclic loading to simulate stresses in the oral environment. Fracture strength was measured using a universal testing machine. Data were analyzed using one-way ANOVA and Tukey’s test (0.05). Fracture strength increased from 157 to 912 N by an increase in ceramic thickness from 0.5 to 1.5 mm. One-way ANOVA showed a significant difference among the three groups in terms of fracture strength (P=0.000). Fracture strength in 1.5 mm thickness was significantly higher than that in the other two groups. The difference in fracture strength was significant in presence of 0.5 and 1 mm ceramic thicknesses. Within the limitations of this study, it may be concluded that increasing the veneering ceramic thickness increases the fracture strength of all-ceramic restorations.