Laboratory strength of glass ionomer and zinc phosphate cements

Abstract

Purpose: The present in vitro study examined 3 mechanical properties, namely compressive, flexural, and diametral tensile strength, of various commercially available cements and core materials as a function of time after mixing. Materials and Methods: The examined materials were 2 cermet cements (Ketac Silver [ESPE, Seefeld, Germany] and Chelon Silver [ESPE]), 1 metal-reinforced glass ionomer cement (Miracle Mix [GC Dental Industrial Corp, Tokyo, Japan]), 2 conventional glass ionomer cements (Ketac Bond [ESPE] and Ketac Cem [ESPE]), 1 standard cure zinc phosphate cement (Harvard Cement [Richter and Hoffmann, Berlin, Germany]), and 1 zinc phosphate cement with the addition of 30% silver amalgam alloy powder (Harvard Cement 70% with Dispersalloy 30% [Richter and Hoffmann/ Johnson and Johnson, East Windsor, NJ]). Properties were measured using a universal testing machine at 15 minutes, 1 hour, and 24 hours after first mixing. Results: Compressive strengths varied widely between the 3 times of measurement from 5.8 ؎ 6.6 MPa for Ketac Cem to 144.3 ؎ 10.2 MPa for Ketac Silver. Twenty-four hours after mixing, the Bonferroni test showed significant (p < .01) differences between Ketac Silver and all other materials tested. Diametral tensile strengths ranged widely from 4.4 ؎ 0.9 MPa for Ketac Cem to 11.5 ؎ 2.2 MPa for Chelon Silver. At 15 minutes, 1 hour, and 24 hours after first mixing, the analysis of variance did not show any significant differences between Ketac Silver, Chelon Silver, and Miracle Mix. The 3-point flexural strength of Ketac Silver showed, at 15 minutes with 13.5 ؎ 3.9 MPa and at 24 hours with 27.2 ؎ 7.4 MPa, the highest values.Conclusions: Setting time influences the mechanical properties of the materials tested in this study. Ketac Silver, a glass ionomer cement reinforced with sintered glass-silver particles, showed the highest mechanical properties of the examined materials.

In Vitro Evaluation of Five Core Materials

“…It has been reported that the diametral tensile strength of the two metal‐reinforced glass ionomer‐based core materials (Ketac‐Silver GIC and GC Miracle Mix GIC) were 12.51 ± 2.22 and 9.71 ± 3.10 MPa, respectively 25 . These values were higher than the values for conventional glass ionomers, 34 yet less than half of the values for the resin composite core materials used in this study. As expected, the fracture strengths of the glass ionomer‐based core materials Ketac‐Silver GIC and GC Miracle Mix GIC were statistically lower than those of the resin‐based core materials used in this study by at least 49% for the same dowel design.…”

Laboratory strength of glass ionomer cement, compomers, and resin composites

“…Under the same testing conditions, Ketac Molar yielded 85.3 ± 32.5 MPa for the compressive strength. The study by Piwowarczyk et al 26 was concerned primarily with the compressive, flexural, and tensile strengths of zinc phosphate and glass ionomer cements. In that study, the metal‐reinforced glass ionomer cement Ketac Silver™ (3M ESPE) showed results similar to Ketac Molar under the same testing conditions as in the present study.…”

Effect of Two Self‐Adhesive Cements on Marginal Adaptation and Strength of Esthetic Ceramic CAD/CAM Molar Crowns

“…An impression was made of this margin section with Enamel 60-90 [26] 41 [33] 400 [27] 10 [33] Dentin 245-280 [26] 18.6 [33] 297 [27] 11.4 [33] Vitablocs [28] 6.3 [29] 80 (24h) [28] 35 [33] a polyvinyl-siloxane impression material (President light body, Coltène, Altstätten, Switzerland) and replicas prepared for quantitative margin analysis in a scanning electron microscope (SEM). Thereafter, molars were stored in tap water at room temperature for at least two weeks before entering the thermo-mechanical cycle.…”

“…Selfadhesive resin-based cements however, show favorable results of marginal adaptation [23] and mechanical support [24,25] of all-ceramic posterior crowns. The question arises whether self-adhesive resin-based cements are able to provide adequate marginal adaptation and strength for esthetic ceramic CAD/CAM crowns with their particular physical properties [26][27][28][29][30][31][32][33][34]. We hypothesized that there would be no difference between resin-bonded crowns and those cemented with self-adhesive resinbased cement with regard to marginal adaptation and strength of ceramic CAD/CAM crowns after extensive thermo-mechanical fatigue stress with dentinal liquid pressure maintained.…”