Compressive and diametral tensile strength of glass ionomer cements

Abstract

The aim of this study was to compare, in different periods of time, the compressive and diametral tensile strength of a traditional high viscous glass ionomer cement: Fuji IX (GC Corporation), with two new Brazilian GIC's: Vitro-Molar (DFL) and Bioglass R (Biodinamica), all indicated for the Atraumatic Restorative Treatment (ART) technique. Fifteen disk specimens (6.0mm diameter x 3.0mm height) for the diametral tensile strength (DTS) test and fifteen cylindrical specimens (6.0mm diameter x 12.0mm height) for the compressive strength (CS) test were made of each GIC. Specimens were stored in deionized water at 37º C and 100% of humidity in a stove until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours and 7 days. The specimens were tested in a testing machine (Emic) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The data were submitted to two-way ANOVA and Tukey tests (alpha=0.05). The mean CS values ranged from 42.03 to 155.47MPa and means DTS from 5.54 to 13.72 MPa, with test periods from 1h to 7 days. The CS and DTS tests showed no statistically significant difference between Fuji IX and Vitro Molar, except for CS test at 1-hour period. Bioglass R had lowest mean value for CS of the cements tested. In DTS test Bioglass R presented no statistically significant differences when compared with all others tested GICs at 1-hour period and Bioglass R presented no difference at 24-hour and 7-day periods when compared to Vitro-Molar. Further studies to investigate other physical properties such as fracture toughness and wear resistance, as well as chemical composition and biocompatibility, are now needed to better understand the properties of these new Brazilian GIC's.

The crushing truth about glass ionomer restoratives: Exposing the standard of the standard

“…The findings demonstrate that the CFS testing protocol is reliable but conflicts with previously reported data [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Considerable efforts were made to standardise techniques and laboratory conditions, however, the large variability in the CFS data reported in the dental literature for GI materials suggests that this level of control is infrequently applied.…”

“…This finding is contrary to the large body of the published information available on GI restoratives in the dental literature [20][21][22][23][24][25][26][27][28][29][30][31][32][33] which includes results of investigations undertaken in the same test centre using the same laboratory protocols [20][21][22][23][24]. The results are also in contrast to the variability identified by the ISO approach using batch-censoring.…”

“…In the current statistical analysis the differences in the CFS data between the three GI restoratives was not of interest, as the reported CFS for GI restoratives vary in accordance with the dental literature [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. As a result, the CFS data for each GI restorative was analysed individually, using three three-way ANOVAs (operator × mixing regime × batch) such that differences between the materials would not influence the analyses.…”

“…In contrast, a significant body of evidence has been presented for GIs [20][21][22][23][24][25][26][27][28][29][30][31][32][33] which could account for the lack of reliability of the CFS test method observed in the 1990 test-house variability study [8]. It has been demonstrated that the proportioning of constituents [20][21][22]24,[37][38], mixing technique [20][21][23][24] and mould design [20][21][22][23][24][26][27][28][29][30][31][32][33] all impact on the recorded strength data. These factors combined with the frequently uncontrolled variables such as laboratory environmental conditions,…”

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.…”