الفهرس 
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Abstract
The surface of each sectioned block was cleaned carefully using a damp cotton pellet. This was followed by examining the vertical gap distance
between the walls of the epoxy die and the fitting surface of the provisional crown under the stereomicroscope using a magnification of X8. The data of the vertical gap distance and the fracture resistance values were collected,tabulated and statistically analyzed.
The results of the current study showed that, the bis- acrylic composite used had higher strength than the pMMA resin used. In the meantime both
materials showed similar mean vertical gap distance values indicating a comparable fit. In addition, both the fracture resistance and the internal fit were adversely affected by the low acidic pH of the surrounding medium.
Sodium hydroxide with the very high alkalinity (pH=13) had a dramatically negative effect on the internal fit of both provisional materials used.