Table 1. Surface conditioning (pre-treatment + primer application) methods to glazed zirconia specimens.

Group code	Pre-treatment	Applied primer
PO-Z	Polishing unglazed (control) zirconia surface with silicon carbide paper	Z-Prime Plus*
BR-Z	Roughening with a diamond bur (grit size: 106 - 125 µm)	Z-Prime Plus
PP-S	Cleaning with a rubber prophy cup and pumice	Monobond-S†
HF-S	4% hydrofluoric acid etching	Monobond-S
AA-S	Air-particle abrasion with 30 µm aluminum oxide particles	Monobond-S
AA-Z	Air-particle abrasion with 30 µm aluminum oxide particles	Z-Prime Plus
CJ-S	Air-particle abrasion with 30 µm silicon dioxide particles (CoJet-Sand)	Monobond-S

PO, polishing unglazed zirconia; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air-particle abrasion with aluminum oxide; CJ, silicon dioxide (CoJet-Sand) particles; Z, Z-Prime Plus; S, Monobond-S.

^*1 - 2 coats were applied and dried with an air syringe for 3 - 5 sec.

^†Applied with a brush, allowed to react for 60 sec, then dispersed with a strong stream of air.