Bond stability of automix self-adhesive resin cement, GAM-100, on ceramics

Objectives: Recently, the high-strength ceramics such as zirconia or alumina are used for many clinical cases. However, there are few cements with high bond stability on the high-strength ceramics. This study evaluated tensile bond strength(TBS) of the trial material, GAM-100(GC), and other two paste-type self-adhesive resin cements to yttria-stabilized zirconia(Aadva Zr-Block: YSZ, GC) and glass-infiltrated alumina(In-ceram ALUMINA: In-Al, VITA).

Methods: TBS test was carried out according to ISO/TS11405. YSZ and In-Al were embedded in acrylic resin. Flat-abraded YSZ and In-Al surfaces were prepared using wet 600-grit silicon carbide paper(#600SiC). Bonding area was prescribed(3mm in diameter) with a plastic tape. The cements were handled following manufacturers' instructions. A stainless steel rod was cemented(self-curing mode) to each substrate. The specimens were stored at 37°C-100%RH for 1hour and soaked in 37°C distilled water for 23hours. For 0-thermocycle specimens(n=5), TBS was measured(1mm/min) after the storage. The other specimens(n=5) were thermocycled(5000, 5/55°C) and followed by the measurement.

Results: In the table, asterisk(*) indicates significant difference(T-test, **: p<0.01) compared with GAM-100 in the same column. GAM-100 showed equivalent TBS to YSZ and In-Al to other cements in 0-thermocycle tests. However, GAM-100 maintained high TBS to YSZ and In-Al even after 5000-thermocycles while the values of other cements significantly dropped.

Cement	Manufacturer	TBS[MPa]
		YSZ		In-Al
		0-cycle	5000-cycles	0-cycle	5000-cycles
GAM-100	GC	38.4(12.9)	40.5(9.1)	50.0(10.1)	47.3(10.6)
productA	companyA	33.5(7.7)	2.4(2.9)**	41.3(10.4)	1.5(0.3)**
productB	companyB	37.2(7.7)	0.2(0.2)**	45.5(8.8)	0.3(0.1)**
(  )S.D.

Conclusion: GAM-100 demonstrates the stable bonding property to the smooth ceramic surface abraded with #600SiC that hardly produces the mechanical interlock. It seems that GAM-100 has chemical interaction to YSZ and In-Al, which enables to maintain the bonding stability after 5000-thermocycles.