Table 2.

Application procedures and contents of the repair systems used in this study.

	Application procedures	Content
Bisco Repair System (B)	1.Apply 1 coat of Z-PRIME Plus to the exposed zirconia, dry with an air syringe for 3-5 seconds.	Porcelain etchant
	2.Apply a thin layer of PORCELAIN BONDING RESIN to the repair site. Spread composite evenly over the surface and light cure.	Porcelain primer
	3. Repair was completed using composite resin and light cured fo 40 seconds	Opaquer catalyst
		Opaquer Base Universal
		Z-Prime Plus
		Porcelain bonding resin
Clearfil Repair System (C)	Clearfil SE Bond Primer and porcelain bond activator were mixed for 5 seconds	K-etching gel
	2.Bonding agent was applied for 10 seconds (air drying) and photo-polymerization for 40 seconds)	Clearfil SE Bond
	3. Repair was completed using composite resin and light cured fo 40 seconds	Porcelian bond activator
Ivoclar Repair System (I)	1.Monobond Plus was applied and allowed to react for 60 seconds and after air dried.	IPS Empress Direct Opaque Monobond Plus
	2.Thin layer of Heliobond was applied and light cured for 90 seconds	Heliobond
	3. Repair was completed using composite resin and light cured fo 40 seconds
Ultradent Porcelain repair system (U)	1.Apply Hydrofloric acid on metal surface for 90 second	PermaFlo Dentin Opaquer
	2.Apply silane and leave 1 minute	EtchArrest
	2.Apply Peak Universal bond for 10 second and light cure for 20 second	OpalDam
		Peak Universal Bond
		Porcelain Etch
		Ultradent Silane
Single Bond universal adhesive (S)	1.Apply on surface of Zirconium leave it for 20 second dry with air for 5 second	Single bond universal adhesive
	2.Light cure for 20 seconds