Assessment of Micro-Hardness, Degree of Conversion, and Flexural Strength for Single-Shade Universal Resin Composites

Abstract

Single-shade universal resin composites (SsURC) are preferred in clinical practice to reduce time for shade selection and obtain good esthetic results. In this study, the static mechanical properties of seven new SsURCs were investigated, their spectral analyzes were performed and scanning electron microscopy (SEM) evaluations were presented. Charisma Diamond One/DO, Admira Fusion x-tra/AFX, Omnichroma/OC, OptiShade/OS, Essentia Universal/EU, Zenchroma/ZC, Vittra APS Unique/VU were used in a three-point bending test to determine flexural strength (FS) and elastic modulus (EM); Vickers micro-hardness (VHN) and hardness-ratio (HR) were performed with a micro-hardness tester from top/bottom after 24-h/15-days of storage in distilled water at 37°C (±1 °C). The degree of conversion (DC) was assessed by using Fourier transform infrared spectroscopy (FTIR). The structure of the resin matrix and filler content were assessed by SEM. Data were analyzed using IBM SPSS V23 and the R program and the significance level was taken as p < 0.05. The main effect of the tested SsURCs was found to be statistically significant on FS, EM, VHN, and DC values (p < 0.001). Bis-GMA free SsURCs (AFX, DO, VU) showed better DC and HR except for OC. All seven tested SsURCs conform to the requirements of ISO standards for dental resin composites for all tested categories.

Evaluation of Fracture Toughness and Micro hardness of Three Current Resin Composite Restorative Materials.

“…The two hybrid resin composites (the nano hybrid Tetric N -Ceram, and the hybrid Te-Econom Plus); possess adequate fillers content (about 81 % by weight). Increasing the fillers content has been reported to result in higher hardness and fracture toughness (1,(18)(19)(20) . Also, the fillers particle size, and loading level have a great impact on the fracture toughness and surface microhardness (1,2,7) .…”

“…Increasing the fillers content has been reported to result in higher hardness and fracture toughness (1,(18)(19)(20) . Also, the fillers particle size, and loading level have a great impact on the fracture toughness and surface microhardness (1,2,7) . Both hybrid resin composites (the nano hybrid Tetric N-Ceram, and the hybrid Te -Econom Plus); have adequate fillers particle size and loading levels which accounts for their, relatively, high surface micro-hardness and fracture toughness.…”

“…Resin composites are vastly and increasingly used in dental restorative procedures due to their appropriate mechanical, esthetic, and physical properties as well as improvements in adhesive dentistry (1)(2)(3)(4)(5)(6) . The recent developments in fillers types and content as well as in polymers, have lead to a broad spectrum of resin composite materials that fulfil the requirements of each clinical situation (2,7) .…”

“…The recent developments in fillers types and content as well as in polymers, have lead to a broad spectrum of resin composite materials that fulfil the requirements of each clinical situation (2,7) . Resin composite materials should demonstrate appropriate mechanical strength to endure forces in high stress-bearing areas, or else these forces could induce bulk fracture and destruction of restorations (1) . Therefore, resin composite materials used for anterior teeth restorations such as in class III or class IV restorations at the incisal edges; should be entirely fracture-resistant to withstand the high flexural forces (8) .…”

Microleakage and Marginal Integrity of Ormocer/Methacrylate-Based Bulk-Fill Resin Restorations in MOD Cavities: SEM and Stereomicroscopic Evaluation

“…Dental restorative materials using ormocer (Organic-Modification-Ceramic) technology, produced as a result of inorganic/organic matrix modifications, exhibit a higher degree of conversion and wear resistance due to the presence of a cross-linked polymer network [ 21 , 22 , 23 ]. Since then, gradual improvements in the organic and inorganic matrix structure of these materials have led to the introduction of pure-silicate-technology-based composites.…”