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The purpose of this study was to evaluate the color stability of aesthetic restorative resin-matrix materials after their immersion in different dietary and therapeutic solutions. Thirty disc-shaped specimens (10 × 2 mm) were prepared from three different types of resin-matrix composites used in dentistry (BE, FS, AF). The color coordinates (L*a*b*, ΔL*, Δa*, Δa*, Δb* and ΔE*) were measured using a VITA Easyshade 3D-Master (VITA Zahnfabrik, Bad Säckingen, Germany) before and after the immersion of the specimens in coffee, red wine, Coca-Cola®, Eludril Care®, and distilled water solutions for 40 h. The color change (ΔE*) was calculated and analyzed by the Kolmogorov -Smirnov test and the Kruskal -Wallis multiple-comparison test. All the restorative materials showed significant color (ΔE*) changes after their exposure to red wine, followed by coffee and Coca-Cola®; however, one nanohybrid resin-matrix composite showed a high color stability in such colored test solutions. The chemical composition and content of the organic matrix played a key role in the color stability of the resin-matrix composites. Clinicians should advise their patients about the chemical interaction between dietary substances and different resin-matrix composites.

In dentistry, clinicians mainly use dual-cured or light-cured resin-matrix cements to achieve a proper polymerization of the organic matrix leading to enhanced physical properties of the cement. However, several parameters can affect the polymerization of resin-matrix cements. The main aim of the present study was to perform a scoping review on the degree of conversion (DC) of the organic matrix, the polymerization, and the light transmittance of different resin-matrix cements used in dentistry. A search was performed on PubMed using a combination of the following key terms: degree of conversion, resin cements, light transmittance, polymerization, light curing, and thickness. Articles in the English language published up to November 2022 were selected. The selected studies’ results demonstrated that restorative structures with a thickness higher than 1.5 mm decrease the light irradiance towards the resin-matrix cement. A decrease in light transmission provides a low energy absorption through the resin cement leading to a low DC percentage. On the other hand, the highest DC percentages, ranging between 55 and 75%, have been reported for dual-cured resin-matrix cements, although the polymerization mode and exposure time also influence the DC of monomers. Thus, the polymerization of resin-matrix cements can be optimized taking into account different parameters of light-curing, such as adequate light distance, irradiance, exposure time, equipment, and wavelength. Then, optimum physical properties are achieved that provide a long-term clinical performance of the cemented restorative materials.

Introduction: In recent years, resin-matrix composite materials have revealed a fast technological improvement for dental applications. However, there are still some drawbacks related to the chemical composition, polymerization, and mechanical properties of resin-matrix composites with consequences in long-term clinical success. Objective: This study aimed to perform a narrative review regarding the effects of inorganic fillers on the organic matrix polymerization of resin-matrix composites. Materials and Methods: A search was performed in PubMed using relevant related key terms related to the chemical composition, properties and polymerization of resin matrix composites. Relevant studies published between 2001 and 2021 were selected. Results: The studies included in the present research provided relevant information on the chemical composition and properties of resin composites and polymerization factors, including the time, wavelength mode, and equipment. Studies have reported that silica and silicate nano-scale particles improve light transmission through resin-matrix composites and the degree of conversion of monomers in the organic matrix. Micrometric particles with a high refractive index can decrease the degree of conversion of monomers in the organic matrix. Conclusion: The polymerization of resin matrix composites is affected by light scattering due to the type of inorganic particles and the differences in refractive indexes of inorganic and organic contents.

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