Yes, if you hope to achieve optimal and reliable cementation results. Removing contaminants from the restoration will help to achieve better bond strengths.
If the crown has been sandblasted, then after try-in, clean the internal surface of the zirconia surface with ZirClean™ and then proceed with applying a primer to the bonded surface of the restoration with a suitable primer (Z-PRIME™ Plus or PORCELAIN PRIMER) according to manufacturer’s instructions.
If the surface wasn’t sandblasted, then sandblast the intaglio surface of the zirconia, and proceed with applying Z-PRIME Plus.