Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Abstract

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

Two-body wear and surface hardness of occlusal splint materials

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Evaluation of New Hollow Sleeve Composites for Direct Post-Core Construction

“…In the current research study, FRC specimens were submitted to artificial hydrothermal accelerated aging by boiling the specimens in water. The length of boiling time was according to previous studies, which reported a decrease in the dental composite strength after the first 16 h of immersing specimens in boiling water [ 19 , 20 ]. As a result, the flexural strength and modulus were significantly decreased after hydrothermal accelerated aging ( p < 0.05), except for groups D, G, and H which showed no differences in the flexural modulus.…”

Improved Flexural Properties of Experimental Resin Composites Functionalized with a Customized Low-Sodium Bioactive Glass

“…Despite the fact that laboratory simulations of material aging cannot simulate all complexities of the mechanical, chemical, thermal, and microbiological factors affecting material degradation under clinical conditions, artificial aging is useful for evaluating material properties after its structure has been permeated with water (or some other solution) and consequently underwent the effects of hydrolysis, plasticization, and repeated stressing of the filler/matrix interface [ 22 ]. Today’s resin composites are known to perform favorably shortly after curing, whereas a more realistic mechanical behavior is seen only after artificial aging [ 40 ]. Hence, regardless of the selection of artificial aging protocol, simulated degradation of the material helps to obtain values of mechanical properties that are more representative of a realistic composite restoration.…”