In-vitro assessment of physico-mechanical properti es of nanopartic le glass carbomer

Aim: This study was conducted to evaluate and compare the shear bond strength, water sorption,
solubility, microhardness, and compressive strength of a recent product of glass ionomer
(Glass Carbomer) compared to conventional glass ionomer.
Materials and Methods: Twenty primary molars were utilized for assessment of shear bond
strength (SBS) test. Crown surfaces of the selected teeth were fixed in acrylic blocks then, ground
with water-cooled silicon carbide papers to obtain a flattened dentin surfaces. The specimens
(n=20) were distributed into two equal groups according to the type of glass ionomer cement (GIC)
bonded to the dentin surface (10/ each group): group I (Fuji IX GP) and group II (Glass Carbomer).
To measure shear bond strength (SBS) a universal testing machine was used. For measurement
of water sorption (WS) and solubility (SL) 10 specimens of each material were prepared and immersed
in artificial saliva of pH 7 for seven days. The difference between initial and final weight
was estimated. Microhardness was estimated using a Vickers microhardness tester. Compressive
strength was evaluated using a universal testing machine.
Results: No significant difference in shear bond strength and microhardness between both
materials. The water sorption, solubility and compressive strength of CAR (Glass Carbomer Fill)
were significantly greater than that of Fuji IX.
Conclusions: Glass Carbomer demonstrated some favourable results. Among these include
the higher compressive strength and comparable shear bond strength and microhardness of glass
carbomer, compared to conventional GIC. On the other hand glass carbomer showed higher water
sorption and solublity than conventional GIC. Thus, glass carbomer holds a promise to be used as
a potential restorative material particularly in pediatric dentistry.