INFLUENCE OF LAMINATION ON THE FLEXURAL STRENGTH OF A DENTAL CASTABLEGLASS-CERAMIC

This study evaluated the effect of veneering Dicor castable ceramic wi th Vitadur N and Dicor Plus feldspathic porcelains, A biaxial flexure test was conducted on five groups of specimens (Dicor castable ceramic , Vitadur N dentinal porcelain, Dicor Plus dentinal porcelain, Dicor c ore veneered with Vitadur N and Dicor core veneered with Dicor Plus ca stable ceramic). Each group consisted of 10 disks of nearly identical dimensions with a 1.98 +/- 0.04 mm thickness and 15.7 +/- 0.35 mm in d iameter. Statistical analysis indicated that there was neither signifi cant difference (p > 0.05) between mean flexural strength of Dicor Plu s and Vitadur N ceramic or Vitadur N and Dicor/Vitadur N ceramic speci mens, The mean flexural strength of Dicor/Vitadur N specimens was sign ificantly lower than the mean flexural strength of Dicor ceramic speci mens. Conversely, there was no significant difference between mean fle xural strength of Dicor ceramic and Dicor/Dicor Plus ceramic specimens . Scanning electron microscope (SEM) examinations of Dicor/Dicor Plus ceramic specimens suggested better wetting of Dicor core by Dicor Plus ceramic with lower incidence of porosity at the interface, However, D icor/Vitadur N ceramic specimens exhibited a higher incidence of poros ity at the interface, This indicated that lamination of Dicor castable ceramic material with feldspathic porcelain for esthetics could be at tained without sacrificing strength of the original material, provided that appropriate veneering material was selected.