Influence of surface treatment of glass-ceramics on TBS of RMGICs

Objective s: The aim of this study was to evaluate the influence of surface treatment for ceramics on tensile bond strength (TBS) of an experimental resin-modified glass-ionomer cement (RMGIC) “FL-901”.

Methods: Specimens of Lithium disilicate glass-ceramics (IPS e.max CAD, Ivoclar) were prepared with #600-grit silicon carbide paper. Prior to preparing the cement layer, the surfaces were subjected to the following treatment: (1)untreated; (2)etching by 4.7% hydrofluoric acid solution for 20s; (3)etching followed by ceramic primer (GC) treatment. The bonding area (3mm diameter, 0.1mm thickness) was defined by plastic tape and the cement layer was prepared with FujiCEM Automix (GC) and FL-901 according to manufacurer’s instructions. Stainless-steel rods were cemented with G-CEM Automix (GC). The specimens were stored at 37°C and 100% R.H. for 1hour, and then submerged in 37°C distilled water for 23hours. Thermal-cycling was (5-55°C 2000cycles) performed for each condition. TBS was measured using AG-I/20kNT (Shimadzu) (Crosshead speed 1mm/min.). Fracture morphology of specimens was also checked (interfacial; IF, cohesive; CF and mix; IF+CF).  

Results: FL-901 was significantly higher TBS than that of FujiCEM on #600-grit surfaces (t-test, *:p<0.05). TBS could not be elevated by surface treatment (t-test, **:p<0.05).

Conclusion s: TBS of FL-901 was remarkably higher than that of FujiCEM on #600-grit surface. There are no effects on surface treatment for TBS of FL-901. It was suggested   FL-901 did not need pre-treatment to work with glass-ceramic prosthesis.

 

		TBS(n=5) [MPa]			Fracture morphology(%)
		#600	etching	Etching +priming	#600			etching			etching+priming
					IF	CF	IF+CF	IF	CF	IF+CF	IF	CF	IF+CF
24hours	FL-901	15.7(2.9)*	15.1(3.3)**	16.2(2.8)**		100			100			100
	FujiCEM	11.2(2.7)	15.8(5.0)	14.8(4.2)		80	20		80	20	20	80
TC2000	FL-901	12.7(2.9)*	11.2(5.4)**	8.9(2.0)**		60	40	40	60		80	20
	FujiCEM	5.8(3.4)	8.1(2.2)	6.8(1.1)	60	20	20	20	40	40	100