Effect of food simulating liquids on the flexural strength of a methacrylate and silorane-based composite

Abstract

ObjectiveThe purpose of this study was to assess the effect of food-simulating liquids on the flexural strength of a methacrylate-based and a silorane-based resin composite.Materials and methodsIn this in vitro study, sixty specimens of Filtek P90 and Filtek Z350 composite were prepared in a customized mold (2 × 2 × 25 mm). The specimens of each composite were divided into five subgroups as follows: one as a control group and the other four groups included distilled water, heptane, 2% citric acid, and 50% aqueous ethanol. The specimens were stored in the solutions for one week at 37°C, and the control group was stored at room temperature for the same period of time. Then, flexural strength values were measured. The statistical analysis was performed by One-Way ANOVA, Paired T test and post hoc LSD at a significance level of 0.05.ResultsIn the control group, the mean flexural strength of Filtek P90 and Filtek Z350 were 155.1 MPa and 147.3 MPa, respectively, and there was no significant difference (P-value>0.05). The mean flexural strength of Filtek P90 and Filtek Z350 significantly decreased in ethanol (P-value <0.05). Immersion in 0.02 N citric acid and heptane had no significant effect on the flexural strength of Filtek P90 and Filtek Z350. The maximum flexural strength of Filtek P90 was in the heptane group (192.6 MPa) and minimum flexural strength was in ethanol group (92.7 MPa) the maximum flexural strength of Filtek Z350 was in the heptane group (163.2 MPa) and minimum flexural strength was in the ethanol group (104.7 MPa).ConclusionThe flexural strength of tested resin composites significantly affected by ethanol solution. The flexural strength of resin composites was not affected by other food simulating liquids.

Shear bond strength of a flash-free orthodontic adhesive system after thermal aging procedure

“…The continuous temperature changes performed in thermocycling have an influence on the bonding materials, causing the resin to expand and contract, as its thermal expansion coefficient is higher than that of the teeth; the higher the thermal expansion coefficient of a resin, the worse it would be for the adhesive interface as volumetric changes of the resin will be greater. Moreover, the presence of water during this procedure causes hygroscopic expansion as well as chemical degradation of the resinous components, a process known as plastification (23). This deleterious effect of thermal changes and hydrolytic degradation has been more relevant for the first 10,000 cycles, without a significant decrease in SBS values when the number of cycles was doubled; similarly to what happened to Turk et al (21) who did not find any significant difference between 10,000 and 20,000 cycles for Transbond XT Light Cure Adhesive (3M Unitek).…”

Effect of food-simulating solvents on flexural properties of bulk-fill resin composites

“…A previous study reported that a composite material with a low modulus of elasticity when placed in stress-bearing areas suffered greater distortion and marginal deterioration under masticatory forces [8]. Several studies have reported the effects of food-like agents on the mechanical properties of dental composites [9,10], and the mechanical stability of bulk-fill restorations in stress-bearing areas remains a challenge to be addressed. Accordingly, the effects of food-simulating solvents on the flexural properties of bulk-fill composites must be evaluated.…”

Comparison of the water sorption and solubility of four reline acrylic resins after immersion in food-simulating agents

“…[12] Water sorption in moderate amounts releases the internal stresses induced by polymerization shrinkage, compensates for the shrinkage, and consequently, improves the marginal seal. [13141516]…”