ABSTRACT
The retention is the property of a restoration in opposing itself to displacement, when submitted to forces along its long axis of insertion, in order to dislodge it.[29] This property can be influenced by preparation area, height, convergence angle, surface state and the existence of a residual dentinal layer (“smear layer”).[14,28]
The cementation of restorations has a key role on its retention. The zinc phosphate cement is characterized by its easy manipulation, good compression resistance, reasonable working time and acceptable film thickness (25 μm).[8] The zinc without eugenol cement shows good consistency, easy manipulation, thin film thickness and inferior compression resistance than other cements. The polycarboxylate cement has chemical bonding to enamel and dentin, acceptable film thickness, low compression resistance and high traction resistance.[23,26]
Everest (KaVo®) is a CAD/CAM system (“computer-assisted design/computer-aided manufacture”) to fabrication of fixed prosthesis and
1 INTRODUCTION
The success of oral rehabilitations by fixed prosthesis is profoundly related with the retention of restorations. The retention can be influenced by several factors, such as the cement used or the spacing between the restoration and the infrastructure.[5,14,27,31]
The spacing is defined as the space between the dental pillar and the prosthesis, and its objective is to accommodate the cement pellicle.[22] It is extremely important to the accuracy of the restoration, good marginal adaptation, disposal of excess cement[35] and it can be created directly on the working model or virtual models.
