Simultaneous Evaluation of Creep Deformation and Recovery of Bulk-Fill Dental Composites Immersed in Food-Simulating Liquids

Abstract

The aim of this study is to compare the creep/recovery behavior of bulk-fill dental composites after storage in various food simulating organic solvents. For this purpose, five different resin-composites (four bulk-fills and one conventional) were used. A total of 20 rectangular specimens (14 mm × 3 mm × 0.7 mm) were prepared by filling the resin-composites in Teflon mold. All of the specimens for each material (n = 5) were divided into four groups namely dry (control), distilled water (DW), artificial saliva, and absolute ethanol. The specimens were subjected to three-point bending creep test during immersion directly. A constant load of 2 N was used for each specimen with loading and unloading time 2 h each. Results: SF2 and XF showed a lower creep strain % after immersion, ranging from 0.44 (dry) to 0.75 (saliva) and 0.43 (dry) to 0.80 (ethanol), respectively. TNC BF depicts the maximum creep strain % ranging from 1.24% (dry) to 2.87% (ethanol) followed by FBF ranging from 1.17 (dry) to 2.59 (ethanol). However, the conventional material (GR) showed lower creep strain after immersion ranging from 0.28 to 0.54. Moreover, SF2 resulted in the highest creep recovery in all of the composites groups, as well as conventional material. The other composite groups showed lower creep recovery as compared to the conventional material (GR). The creep strain % for all the bulk-fill composites materials were increased during immersion in the liquids. However, for the conventional material, the creep deformation is decreased after immersion. SF2 showed the highest percentage of creep recovery among the bulk-fill composites, followed by XF.

Effect of Dietary Challenges on the Flexural Properties of Resin-based Composites

“…Chemical degradation of dental composites after exposure to adverse oral environment especially dietary liquids can remarkably challenge their flexural properties [25]. This is initiated by water absorption that causes dissolution or elution of leachable inorganic filler particles and residual monomers, thus destroying the polymeric network of the material [26]. In addition, leaching of filler particles into oral environment may compromise the biocompatibility of the restorative materials [27].…”

Time-temperature behavior of carbon/epoxy laminates under creep loading

“…The long-term of such high-performance composites is important to be quantified, given the viscoelastic nature of polymeric matrices (Guedes 2006). A very few studies are found in the literature dealing with the long-term mechanical behavior relating thermoset matrix composites (Sullivan 1990;Sullivan et al 1993;Hu and Sun 2000;Fancey 2001Fancey , 2005Alrahlah et al 2018). Fancey (2001Fancey ( , 2005 mentioned the importance of low-stress creep response for the tensile modulus prediction.…”

“…Fancey (2001Fancey ( , 2005 mentioned the importance of low-stress creep response for the tensile modulus prediction. A low-stress level analysis allows a fast and inexpensive way in relation to structure versus property relationship (Alrahlah et al 2018;Fancey 2001Fancey , 2005. General failure mechanisms are present in two main scales, (i) microscopic and (ii) macroscale mechanisms that arise from microstructural changes (Khan et al 2015).…”

“…In other words, the microstructural mechanical performance is an important factor for determining macrostructural changes, considering physical aspects (Alderliesten 2015;Khan et al 2015). In this perspective, dynamic-mechanical analysis (DMA) allows determining the creep behavior and observe microstructural changes (molecular mobility) (Alrahlah et al 2018;Fancey 2001;Mano et al 2004). For instance, the elastic modulus can be predicted by measuring different load levels and considering the reciprocal of the gradient from a linear regression line, showing good correlation with the experimental data analyzed, encouraging to note that the instantaneous deformation values agree with available tensile modulus data (Fancey 2001).…”

Creep/recovery and stress-relaxation tests applied in a standardized carbon fiber/epoxy composite: Design of experiment approach

“…Tensile and flexural, 1 interlaminar shear, 2 and crack propagation 3,4 are among the more frequently used tests regarding polymeric composite materials. Other mechanical properties studied are creep, 5,6 recovery, 7,8 and stress relaxation. 9,10 Creep is the permanent deformation in a material when subjected to a constant force or stress, being a function of time.…”