Effects of storage, thermal and load cycling on a new reinforced glass-ionomer cement

Abstract

The objective of this in-vitro study was to determine the influences of storage, thermal and load cycling as well as combinations of these treatment procedures on the microleakage patterns of a new 'condensable' silver reinforced restorative glass-ionomer cement (Shofu Hi-Dense®). Class II preparations with gingival margins in dentine were made on 50 freshly extracted, non-carious molar teeth and restored with Shofu Hi-Dense® according to the manufacturer's instructions. The restorations were subsequently stored for 1 week, finished and randomly assigned into five groups of 10 and treated as follows: Group 1 - control (uncycled); Group 2 - thermocycled; Group 3 - mechanically load cycled; Group 4 - three months storage, uncycled; Group 5 - three months storage, thermal and load cycled. The storage medium throughout the experiment was artificial saliva at 37°C. All treatment procedures had no significant influence on microleakage at the enamel-cement interface. These treatment modalities, however, resulted in a significant increase in leakage at the dentine-cement interface. With the exception of the 1 week storage, uncycled group, the dentine-cement interface had significantly greater leakage than the enamel-cement interface. © 1998 Blackwell Science Ltd.