Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

The aim of the present study was to evaluate the effect of two different surface treatments (sandblasting and silica coating) of cosmopost on retention to different core materials using push out test set - up. A total of 30 cosmoposts were used in this study. Cosmoposts were divided into 3 groups (10 samples each) according to the post - surface treatment received: Each group was further subdivided into 2 subgroups according to the type of core material (n = 5 samples): A specially designed copper mold was used for construction of different core materials with standardized dimensions around the posts, in such a way to ensure that the posts will be centralized. Surface roughness was estimated for all cosmoposts, following different surface treatments using SEM. Cylindrical cores were fabricated of either composite resin or, heat - pressed zirconia - containing glass ceramic (IPS empress cosmo, IvoclarVivadent) following the construction of different core materials, samples were subjected to push-out test set - up to evaluate the effect of different treatments on post/core bond strength. Data was collected, tabulated and statistically analyzed. SEM was performed on cosmoposts following different treatments, and following debonding of different post/core samples to determine their mode of failure

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