Reconstruction of endodontically treated posterior teeth use now dual or chemical cure core build-up materials. Core build-up materials have mechanical properties still unknown. These properties have consequences on survival of reconstruction and on the tooth. For the same material family, the operator feelings may be very different depending on resin flowability. The aim of this study was to evaluate the viscosity (processing properties) and some mechanical properties (in service properties) of different resins. For example: If the resin is very viscous it is difficult to fill the root canal If the resin is very flowable, injection is facilitated but what about the mechanical properties (stiffness, yield stress, hardness, …)? The resins properties were obtained from shear rheometry, flexural vibration analysis, micro-indentation and micro-hardness.