Hertzian load-bearing capacity of a ceramic-reinforced glass ionomer cement stored wet and dry

Abstract 

Objective

To investigate the development of the load-bearing capacity of a ceramic-reinforced glass ionomer cement (GIC), stored dry or wet, using Hertzian indentation.

Methods

GIC discs 2mm thick and 10mm in diameter were made (Amalgomer CR, Advanced Healthcare, Tonbridge, Kent, UK), randomly divided into 8 groups and stored at 37°C in air or artificial saliva (AS) for 1, 7, 30 and 90 days. Discs were tested by loading centrally using a 20mm diameter hard steel ball while resting freely on a filled-nylon substrate (E: 10GPa), at 23°C in air. The failure load at the first bottom-initiated radial crack was detected acoustically.

Results

All the failure loads of air-stored specimens were higher than those of AS-stored specimens. The failure load was relatively stable for air-stored specimens but showed a significant decreasing tendency for AS-stored specimens.

Significance

Zirconia-reinforced GIC is sensitive to moisture. Artificial saliva storage has a detrimental effect on the failure load of ceramic-reinforced GIC that may indicate long-term deterioration in service.

Keywords: Ceramic-reinforced glass ionomer cement (GIC), Storage medium, Load-bearing capacity, Hertzian indentation