Mechanical properties of two restorative reinforced glass-ionomer cements.
ABSTRACT This study investigated the mechanical properties (hardness, compressive and diametral tensile strength) of two restorative reinforced glass-ionomer cements (GC Fuji IX GP and Miracle Mix). The mechanical properties of the two cements were compared after 1 day, 1 week and 1 month storage in distilled water at 37 degrees C. Hardness testing (VHN) was carried out with a digital microhardness tester (load = 50 g, dwell time = 30 s) and compressive/diametral tensile strength testing (MPa) was conducted based upon British Standard Specification for Glass-Ionomer Cements (BS 6039: 1981). Results were analysed using analysis of variance (ANOVA)/Scheffe's test and independent samples t-test (P < 0.05). Mechanical properties generally increased with time for both cements. Hardness at 1 day was significantly lower than that at 1 week and 1 month. No significance difference in compressive and diametral tensile strengths was observed between the different time intervals. After 1 month storage in water, no significant difference in hardness and compressive strength was observed between Fuji IX and Miracle. The diametral tensile strength of Fuji IX was, however, significantly greater than that of Miracle Mix at all time intervals. Fuji IX GP may serve as a potential substitute for Miracle Mix.
[show abstract] [hide abstract]
ABSTRACT: The aim of this study was to determine constitution and physical properties of a prototype material based on Portland cement and assess biocompatibility compared with glass-ionomer cement by evaluating cell morphology. Analysis of the material was performed using energy dispersive analysis (EDAX) and X-ray diffraction (XRD) analysis. Compressive strength and the effect of changing the mixing and curing conditions on the compressive strength of the materials were evaluated. Dimensional stability was evaluated by measuring water uptake of the materials. Biocompatibility was assessed at 1 and 28 days using a cell-culture technique and semi-quantitative cell morphological evaluation was performed by SEM. Analysis of the material showed that it was primarily composed of tricalcium silicate and dicalcium silicate. The compressive strength of the prototype cement and variants was comparable to Ketac Molar (47.98 N mm(-2) after 1 day, P>0.05). Vacuum mixing did not improve the compressive strength of the prototype cements at any age. Wet curing was detrimental to the neat cement at 1 day (35.98 N mm(-2), P=0.011) and 7 days (44.08 N mm(-2), P=0.025). The filler-replaced cement prototypes were more stable and less susceptible to changes in compressive strength by varying the curing method (P>0.05). The prototype material took up more water (0.9%) than glass-ionomer cement (1.7%) with P=0 after 1 day. Curing at 100% humidity resulted in a net loss of weight for all the materials tested. The test materials were less biocompatible than glass-ionomer cement at 1 day but their biocompatibility improved as the material aged. The constitution of the prototype material was broadly similar to that of mineral trioxide aggregate. The prototype cement could be a potential dental restorative material as its compressive strength compared well to an established restorative material. However, the material did not support cell growth, with biocompatibility being similar to that of glass-ionomer cement.Dental Materials 03/2008; 24(3):341-50. · 3.13 Impact Factor