Zirconia cementation is simplistic. The post cementation caveat is the interphase between the cement and the internal surface of the Zirconia crown.  Zirconia is slick to cement.  Conditioning Zirconia with a metal primer is only effective if the phospholipids can be removed.  Ivoclean is the solution followed with Monobond Plus.  When using a resin glass ionomer cement, the crown cement will have adhesive properties and still retain glass ionomer cement interphase to the tooth.  If for some reason the crown needs to be removed one day, this approach will provide a merciful option if the time every comes.