TheraCem contains MDP which offers an optimal bond to both zirconia and the tooth structure, without the need to apply a primer prior to cementation. TheraCem has a very high bond strength (25~30 MPa) to zirconia due to its MDP component.
However if bonding to a Porcelain or Glass-based restoration, BISCO recommends priming with pure Silane, prior to cementation with TheraCem.