Influences of Different Air-Inhibition Coatings on Monomer Release, Microhardness, and Color Stability of Two Composite Materials

Abstract

The aim of this study was to evaluate the effect of light-curing protocols on two modern resin composites using different air-inhibition coating strategies. This was accomplished by assessing the amount of monomer elution, surface microhardness, and composite discoloration in different storage conditions. A total of 120 specimens were prepared using Filtek Supreme XTE (3M ESPE, Seefeld, Germany) and CeramX Universal (Dentsply DeTrey, Konstanz, Germany). Specimens were light-cured in air as per manufacturer’s instructions or in the absence of oxygen. This latter condition was achieved using three different approaches: (i) transparent polyester strip; (ii) glycerin; (iii) argon gas. Specimens were assessed for release of monomers, Vickers hardness, and discoloration after storage in different solutions. The results were analyzed with ANOVA one-way test followed by Student-Newman-Keuls test. Moreover, multiple comparisons of means were performed using the Student t-test (p<0.05). The amount of monomers released from the tested specimens was very low in all conditions. The presence of oxygen induced some decrease in microhardness. The highest discoloration values, for both materials, were obtained after ageing in red wine. In case finish and polish procedures are awkward to achieve in posteriors composite restoration, light-curing in the absence of oxygen should be considered, especially when performing composite restoration in esthetic areas.

The Ability of Coffee to Stain Nanohybrid Composite Resins

“…According to coffee manufacturers, it takes an average of 15 min to drink a cup of coffee and drinkers consume an average of 3.2 cups of coffee per day (12). Moreover, Marigo et al (13) stated that in vitro incubation of composite resin specimens in different staining solutions for 24 hours may correspond to approximately 30 days in vivo. Thus, storage for 48 h in coffee simulates an average of two months of coffee intake and consequently seven months in case of 7 days.…”

Evaluation of Surface Roughness of Composite, Compomer and Carbomer After Curing Through Mylar Strip and Glycerin: A Comparative Study

“…Mylar strips, use of helium gas, and topical application of glycerin have been investigated to eliminate the oxygen that yielded promising results. [6][7][8][9]10 In the dental literature, application of glycerin has been shown to improve the wear resistance of composite resins as well as marginal adaptation of adhesively luted composite inlays. 8 Microhardness was evaluated in most of the studies since it is an indirect method for evaluating the relative degree of the polymerization effect.…”

“…Hence, complete removal of oxygen inhibition layer has been in the interest scope of researchers and different techniques have been developed and tested and are still being investigated. [6][7][8][9] One of the most recommended techniques is curing of the resin-based restorative material through a mylar strip to avoid air exposition. This is easy to apply for interproximal restorations but in clinical situation occlusal surfaces are hard to cope with.…”

Oxygen Inhibition of Surface Composites and Its Correlation with Degree of Conversion and Color Stability

“…During composite light-curing, the contact of oxygen produces a surface layer of uncured resin (5,6). The oxygen inhibits the polymerization reaction, resulting in the formation of a polymer chain more prone to staining and wearing (5). The oxygen-inhibited layer thickness for composite resins ranges from 4 µm to 40 μm (5).…”