Effect of naturally acidic agents on microhardness and surface micromorphology of restorative materials

Objectives: This study investigated the titratable acidity and erosive potential of acidic agents on the microhardness and surface micromorphology of four restorative materials.

Methods: Forty-seven discs of each restorative material; metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250) and amalgam (Valiant-Ph.D.), 12 mm in diameter and 2.5 mm in thickness, were divided into four groups (5 discs/group). Specimens were then immersed for 7 days into four storage media; deionized water (control), citrate buffer solution, green mango juice and pineapple juice. Microhardness testing before and after immersions was performed. Micromorphological changes were evaluated under a scanning electron microscope (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey's tests.

Results: The Fuji II LC and the Ketac-S showed the highest reduction in microhardness (P<.05). The Valiant-Ph.D. and the Filtek Z250 showed some minor changes over the period of 7 days. The mango juice produced the greatest degradation effect (P<.05).

Conclusions: This study suggested that for restorations in patients who have tooth surface loss, materials selected should be considered. In terms of materials evaluated, amalgam and resin composite are the most suitable for restorations.