Shear bond strength of light-cured glass ionomer to enamel and dentin

The shear bond strengths of a light-cured glass-ionomer cement to enamel and dentin were determined with use of extracted human maxillary permanent canines and molars. Bonding sites on the ground, etched enamel and ground dentin surfaces were demarcated by the punching of a hole, 3 mm in diameter, in an adhesive tape. The mixed glass-ionomer cement was transferred to the demarcated site, cured by exposure to visible light for 30 s, and the cement surface treated with Scotchprep Dentin Primer followed by Scotchbond 2 Light Cure Dental Adhesive. The embedded teeth were positioned in an assembly apparatus, and Silux composite was bonded to the glass-ionomer-cement surfaces. The specimens were disassembled after 15 min and subjected to a shear load (in an Instron machine) immediately after disassembly; after storage in water at 37 degrees C for 24 h, without and with temperature cycling; and after storage in water for four weeks, without and with temperature cycling. The shear bond strength of the glass-ionomer cement to etched enamel was in the order of 12 MN.m-2, and to dentin it was 9 MN.m-2. Temperature cycling and duration of storage had no adverse effect on the shear bond strength. The enamel and dentin aspects of fractured test specimens were examined, and the percentage of the bonding area that failed in the cement was estimated. Most of the test specimens failed partly at the enamel and dentin interfaces and within the glass-ionomer cement.