Halogen lamp and led activation of resin-modified glass ionomer restorative material. In vitro microhardness after long term storage

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ABSTRACT

Aim

The purpose of this study was to evaluate the activation of resin-modified glass ionomer restorative material
(RMGI, Vitremer-3M-ESPE, A3) by halogen lamp (QTH) or light-emitting diode (LED) by Knoop microhardness (KHN) in two
storage conditions: 24hrs and 6 months and in two depths (0 and 2 mm).

Methods

The specimens were
randomly divided into 3 experimental groups (n10) according to activation form and evaluated in depth after 24h
and after 6 months of storage. Activation was performed with QTH for 40s (700 mW/cm2) and for 40 or 20 s with LED (1,200
mW/scm2). After 24 hrs and 6 months of storage at 37C in relative humidity in lightproof container, the Knoop
microhardness test was performed. Statistics Data were analysed by three-way ANOVA and Tukey post-tests (p<0.05).

Results

All evaluated factors showed significant differences (p<0.05). After 24 hrs there were no differences within the experimental groups. KHN at 0 mm was significantly higher than 2 mm. After 6 months, there was an increase of microhardness values for all groups, being the ones activated by LED higher than the ones activated by QTH.

Conclusion

Light-activation with LED positively influenced the KHN for RMGI evaluated after 6 months.

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