Yan Wang1, B W Darvell. 1. Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guang Zhou, China.
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 degrees 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 degrees 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.
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 degrees 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 degrees 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.