Evaluation of Surface Microhardness of Silver and Zirconia Reinforced Glass-ionomers with and without Microhydroxyapatite

• Main Authors: Sharafeddin F (Author), Azar MR (Author), Feizi N (Author), Salehi R (Author)
• Format: Book
• Published: Shiraz University of Medical Sciences, 2017-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 2383-3971; 2383-398X
• Keywords: Glass-ionomer Zirconia-reinforced glass-ionomer; Silver-reinforced glass-ionomer; Microhydroxyapatite; Microhardness; Glass-ionomer; Zirconia-reinforced glass-ionomer; Microhydroxyapatite; Technology; T; Dentistry; RK1-715
• Source: Journal of Dental Biomaterial, Vol 4, Iss 4, Pp 454-460 (2017)

Statement of problem: Hardness of restorative materials like glass-ionomer is an important factor in the longevity of restoration. Objectives: The aim of this study was to evaluate the microhardness of glass-ionomer modified with different materials. Materials and Methods: Sixty disk-shaped specimens were examined in six groups in this study, including conventional glass-ionomer (Shofu, Japan), zirconia-reinforced glass-ionomer (Zirconomer, Shofu, Kyoto, Japan), silver-reinforced glass-ionomer (HI-DENSE XP, Shofu, Kyoto, Japan) and mixture of these three types of glass-ionomer with 20 wt% of microhydroxyapatite (Sigma-Aldrich, St. Louis, USA). All the specimens were stored in deionized water for 24 hours. Then Vickers microhardness test was carried out and the results were analyzed by using two-way ANOVA test and paired t-test (P<0.05). Results: Zirconia-reinforced glass-ionomer with microhydroxyapatite exhibited significantly higher microhardness in comparison with other groups (P<0.001). Conventional glass-ionomer with microhydroxyapatite showed the lowest microhardness (P<0.001). After incorporation of microhydroxyapatite in both conventional and silver-reinforced glass-ionomer groups, microhardness decreased significantly (P<0.001).The microhardness of top and bottom of all groups was significantly different. (P<0.001). Conclusions: Incorporation of 20% microhydroxyapatite to zirconia-reinforced glass-ionomer can improve microhardness.