Microhardness and fluoride release of restorative materials in different storage media

Abstract

This study evaluated the surface microhardness and fluoride release of 5 restorative materials - Ketac-Fil Plus, Vitremer, Fuji II LC, Freedom and Fluorofil - in two storage media: distilled/deionized water and a pH-cycling (pH 4.6). Twelve specimens of each material, were fabricated and the initial surface microhardness (ISM) was determined in a Shimadzu HMV-2000 microhardness tester (static load Knoop). The specimens were submitted to 6- or 18-h cycles in the tested media. The solutions were refreshed at the end of each cycle. All solutions were stored for further analysis. After 15-day storage, the final surface microhardness (FSM) and fluoride release were measured. Fluoride dose was measured with a fluoride-specific electrode (Orion 9609-BN) and digital ion analyzer (Orion 720 A). The variables ISM, FSM and fluoride release were analyzed statistically by analysis of variance and Tukey's test (p<0.05). There was significant difference in FSM between the storage media for Vitremer (pH 4.6 = 40.2 +/- 1.5; water = 42.6 +/- 1.4), Ketac-Fil Plus (pH 4.6 = 73.4 +/- 2.7; water = 58.2 +/- 1.3) and Fluorofil (pH 4.6 = 44.3 +/- 1.8; water = 38.4 +/- 1.0). Ketac-Fil Plus (9.9 +/- 18.0) and Fluorofil (4.4 +/- 1.3) presented higher fluoride release in water, whereas Vitremer (7.4 +/- 7.1), Fuji II LC (5.7 +/- 4.7) and Freedom (2.1 +/- 1.7) had higher fluoride release at pH 4.6. Microhardness and fluoride release of the tested restorative materials varied according to the storage medium.

Evaluation of Fluoride Release, pH and Microhardness of Glass Ionomer Cements

“…Previous studies [14][15][16][17] obtained similar results. High initial fluoride rates released by in vivo GIC contribute to eliminate remaining microorganisms of the oral cavity and to strengthen demineralized enamel and dentin [18].…”

Surface topography and mechanical properties of flax fibres modified glass ionomer restorative materials

“…In the present study, incorporation of flax fibres produced no significant change in the hardness number of GIC; this may indicate that the flax fibres did not interfere with the setting reaction of GIC. The microhardness value obtained for Ketac TM Fil Plus is higher than that recorded in literature [30] ; this could be due to the variation of testing conditions (e.g., load and time of its application), powder/liquid ratio, and preparation method. According to the results of the hardness test, there was no enough evidence to reject the null hypothesis.…”

Microhardness and chemical analysis of high-viscous glass-ionomer cement after 10 years of clinical service as ART restorations

“…14 Although water is the most employed storage medium, current studies attempt to simulate oral conditions (pH-cycling; demineralization and remineralization solutions) on GICs. [15][16][17][18] However, in vitro studies do not effectively reflect what actually occurs in the oral environment, and in situ studies often have short-term results. 19 Van Duinen et al 20 reported that under oral conditions, glass-ionomer gradually changes into a harder and smoother enamel-like structure with increased calcium and phosphate content.…”