The base cement is placed, followed by the cavity varnish in all of the following except:
When a cavity varnish or dentin bonding agent is indicated to seal a restoration, the base often governs the order of material application. If a zinc phosphate cement base is used, a sealing (varnish) material should be applied to the cavity walls before placement of the base. For the more biocompatible cement base materials (e.g., calcium hydroxide, ZOE, polycarboxylate, and GIC), the base cement is placed, followed by the cavity varnish after the base has hardened.
Calcium hydroxide
ZOE
Polycarboxylate
ZnPO4