Polymerization with a micro-xenon light of a resin-modified glass ionomer: a shear bond strength study 15 minutes after bonding.

The purpose of this study was to evaluate the initial shear bond strength (15 minutes after bonding) of a resin-modified glass ionomer (RMGIC, Fuji Ortho LC) cured with two different light-curing units: a conventional visible light (Ortholux XT) and a microxenon light (Aurys). Seventy-five freshly extracted bovine permanent mandibular incisors were randomly assigned to one of five groups; each group consisted of 15 specimens. Group A (Transbond XT) and group B (Fuji Ortho LC) were exposed to the visible light for 20 and 40 seconds, respectively, and used as controls. The remaining three groups (C, D, and E) were bonded with Fuji Ortho LC and cured with Aurys for 10, 5, and 2 seconds, respectively. All samples were tested in a shear mode on an Instron universal testing machine 15 minutes after bonding. The shear bond strength of the control group bonded with Transbond XT was significantly higher (P = 0.000) than those of all the other groups tested. Regarding Fuji Ortho LC, no statistically significant differences were found between the bond strength of the control group cured with Ortholux XT, and those of the groups cured with Aurys for 2, 5, and 10 seconds. The present findings indicate that, compared with visible light-curing, the micro-xenon light enables the clinician to significantly reduce the curing time of RMGICs, without affecting their initial shear bond strengths.