Microhardness of glass ionomer cements indicated for the ART technique according to surface protection treatment and storage time

Abstract

The aim of this study was to assess the microhardness of 5 glass ionomer cements (GIC) -Vidrion R (V, SS White), Fuji IX (F, GC Corp.), Magic Glass ART (MG, Vigodent), Maxxion R (MR, FGM) and ChemFlex (CF, Dentsply) -in the presence or absence of a surface protection treatment, and after different storage periods. For each GIC, 36 test specimens were made, divided into 3 groups according to the surface protection treatment applied -no protection, varnish or nail varnish. The specimens were stored in distilled water for 24 h, 7 and 30 days and the microhardness tests were performed at these times. The data obtained were submitted to the ANOVA for repeated measures and Tukey tests (α = 5%). The results revealed that the mean microhardness values of the GICs were, in decreasing order, as follows: F > CF = MR > MG > V; that surface protection was significant for MR, at 24 h, without protection (64.2 ± 3.6a), protected with GIC varnish (59.6 ± 3.4b) and protected with nail varnish (62.7 ± 2.8ab); for F, at 7 days, without protection (97.8 ± 3.7ab), protected with varnish (95.9 ± 3.2b) and protected with nail varnish (100.8 ± 3.4a); and at 30 days, for F, without protection (98.8 ± 2.6b), protected with varnish (103.3 ± 4.4a) and protected with nail varnish (101 ± 4.1ab) and, for V, without protection (46 ± 1.3b), protected with varnish (49.6 ± 1.7ab) and protected with nail varnish (51.1 ± 2.6a). The increase in storage time produced an increase in microhardness. It was concluded that the different GICs, surface protection treatments and storage times could alter the microhardness values.

Surface Hardness of Glass Ionomer Cements used in Atraumatic Restorative Treatment

“…Surface hardness tests may be applied to evaluate the degradation and durability of dental materials, to observe the effect of storage mediums on the surface, as indicative of resistance to wear and durability, and also to monitor the hardening process of cements [5]. From the results of the present study, the Gold Label 9 Group (Fuji IX) presented the best performance among the cements studied, with data similar to those found in the literature [8,11,[24][25][26]. As observed in Table 1, Gold Label 9 obtained the best hardness mean values and alteration in the powder/liquid ratio of Vitro Molar resulted in a significant increase in surface hardness both after one day and after one week.…”

“…After 7 days of storage the microhardness of Vitro Molar increased from 34.7 VH to 56.53 VH, a behavior which has also been observed in other studies [8,25]. The time interval of measurements (after one day and after one week) was chosen because it was the period with the most elevated increase in hardness, as was observed in a previous study [25].…”

“…The data observed after the 24-hour analysis of Group 1 (Table 1) are similar to those found in other study [5], who pointed out Vitro Molar as having the worst performance among the GICs evaluated, and Gold Label 9 as having the best results. This statistically significant difference could be attributed to the type of material; Gold Label 9 is a high viscosity GIC, with a higher powder/liquid ratio, and shorter setting time [22,25], resulting in better mechanical characteristics and a good clinical repercussion, as was observed in another study [27], in which the success rate of restorations and sealants, by the ART technique, using high viscosity GICs was higher than those of the conventional types.…”

“…As Vitro Molar´s performance is worse than Gold Label 9, probably because of the powder to liquid ratio, we decided to test Vitro Molar with 50% more powder than liquid in order to improve its properties [5]. Gold Label 9 was used as the control group in this study, as it was developed for the specific use in ART and because of its good performance [8,11,[24][25][26].…”

Efeito da técnica de inserção na resistência mecânica de dois cimentos de ionômero de vidro de alta viscosidade

“…O uso combinado de instrumentos manuais e CIV de alta viscosidade torna possível uma melhora na saúde bucal de vários grupos populacionais, pela redução do número de extrações e aumento do número de dentes restaurados, melhora na qualidade de vida da população e satisfação no trabalho do dentista 19 . O CIV de alta viscosidade possui melhor resistência à compressão, ao desgaste e dureza superficial, quando comparado com o CIV convencional [8][9][10][11] . A forma de inserção do CIV nas cavidades dentárias preconizada por cada autor é variável.…”