Bond stability of auto-mix self-adhesive resin cement, GAM-100

Title: Bond stability of auto-mix self-adhesive resin cement, GAM-100

Objectives: This study evaluated shear bond strength(SBS) of various self-adhesive resin cements to tooth structure and yttria-stabilized zirconia(YSZ, Aadva Zr Block from GC). Correlation between flexural strength(FS) and SBS was also examined.

Methods: SBS test was carried out according to ISO/TS11405. Bovine tooth and YSZ were mounted in acrylic resin. Flat abraded enamel and dentin surfaces were prepared using wet 600-grit silicon carbide papers. Flat YSZ surface was sandblasted with 50µm alumina. Bonding area was regulated(3mm in diameter) with a plastic tape. Cements were handled following manufacturers' instructions. Each substrate was cemented(self-curing mode) with a stainless steel rod. The specimens were stored at 37°C-100%RH for 1hour and stored in 37°C distilled water for 23hours. For 0 thermo-cycles specimens(n=6), SBS was measured(1mm/min) at this step. The other specimens(n=6) were thermo-cycled(5000, 5/55°C) and followed by measurement. Meanwhile FS test was conducted according to ISO4049. Specimens(n=6) were self-cured and storing condition was same as 0 thermo-cycles SBS test.

Results: In the following table, asterisk(*) indicates significant difference compared with GAM-100 in same column(T-test, *: p<0.01, **: p<0.05). GAM-100 showed significantly higher SBS to tooth structure than other cements in both 0 and 5000thermo-cycles tests. GAM-100 maintained high SBS to YSZ after 5000thermo-cycles while the values of some cements significantly dropped. FS of GAM-100 was also the highest among these cements.

		SBS[MPa]						FS[MPa]
		Enamel		Dentin		YSZ
Cement	Manufacturer	0cycles	5000cycles	0cycles	5000cycles	0cycles	5000cycles
GAM-100(experimental cement)	GC	26.5(9.9)	32.4(8.6)	26.8(7.4)	33.0(8.9)	67.5(11.3)	63.1(23.5)	166.0(13.4)
RelyXTM Unicem ClickerTM	3M ESPE	16.6(5.3)*	16.7(6.3)*	18.6(7.8)*	17.9(8.5)*	45.4(11.5)**	10.3(3.2)*	94.6(11.2)*
Multilink® Sprint	Ivoclar Vivadent	15.9(8.6)*	17.3(3.8)*	9.6(3.0)*	8.7(0.9)*	46.9(14.0)**	49.6(17.3)	98.0(9.2)*
MaxcemTM	Kerr	17.7(8.2)*	15.2(2.0)*	6.5(3.1)*	2.9(2.9)*	56.3(6.8)	7.5(10.5)*	100.8(6.5)*

Conclusion: GAM-100's high bond stability is considered due to balanced permeability and mechanical strength.