The Effect of Composition, Temperature and Post-Irradiation Curing of Bulk Fill Resin Composites on Polymerization Efficiency

Abstract

Objectives:To evaluate the polymerization efficiency of bulk fill resin-based composites (RBCs) and how their composition, temperature and post-irradiation polymerization influence the results. Methods and Materials: Eight bulk fill RBCs were investigated. Five specimens for each material were prepared for Vickers hardness measurements. The measurements were performed in three depths from the top of the surface of the specimens (0, 2 or 4 mm) immediately and 24 h after polymerization and for the highly viscous bulk fill RBCs after preheating at 54 o C. Statistical analysis was performed using one-way ANOVA and Tukey post hoc tests at a=0.05. Results: As the depth increases microhardness values reduce. The Vickers hardness measurements 24 h after photo-polymerization revealed higher values compared to those obtained immediately after photo-polymerization (p<0.05). There was an increase in microhardness of the RBC materials when preheated at 54 o C in comparison with the room temperature specimens (p<0.05).Conclusions: Polymerization efficiency of bulk fill RBCs is affected by their composition and increases with temperature and post-irradiation polymerization.

Polymerization shrinkage, microhardness and depth of cure of bulk fill resin composites

“…Except for the TBF, which relies on a new dibenzoyl germanium compound (Ivocerin), which absorbs light between 370 and 460 nm and is claimed to be more reactive, the other bulk fill resin composites show the same camphorquinone/amine initiator system, probably relying in changes in the filler contents and higher translucency for improvements on the depth of cure 22,26,34,35,40,41) . A more translucent resin composite can be achieved through reduction in the filler content, use of bigger particles size and study of the interaction between the fillers and organic matrix refractive indexes 21,22) . The increased translucency of the bulk fill resin resin composites can be observed in clinical situation, in which the necessity of a capping layer comes from both mechanical and esthetical properties.…”

“…In addition, use of bigger increments usually are associated with a higher C-factor, which can increase shrinkage stress development 20) . Manufacturers used different approaches to ensure a proper polymerization in deep cavities such as incorporation of new and more reactive photoinitiators, reduction of resin composite's opacity (through filler content changes such as increase in particles size or reduction of the mismatch between fillers and organic matrix refractive indexes) 21,22) . The increased translucency for some resin composites can be observed during clinical use and ensures adequate physico-mechanical properties 23) and long term maintenance of restoration.…”

Microhardness of Two Composite Resins with Different Curing Sources

“…Microhardness of composite resin material does not re ect only the extent of polymerization, but other factors such as ller content (Tetric Evoceram llers are Barium glass, ytterbium tri uride, mixed oxide and prepolymer and Mosaic llers are Ceramic zirconia silica glass and ller size (Tetric EvoCeram llers size: 40 nm-3,000 nm, mean size: 550 nm and Mosaic llers size: 0.02 um) that affects hardness results. (27) It depends also on other factors, such as the organic matrix composition (Tetric EvoCeram organic matrix: Bis-GMA, Bis-EMA, UDMA (21) and Mosaic organic matrix: Bis-GMA, PEGDMA, TEGDMA) (28) as the polymerization level varies according to the amount of monomers and oligomonomers present in the composite resins (19) Also, Young's modulus of elasticity and viscosity plays major role in the microhardness results. The composite resin viscosity is correlated with the type of resin matrix.…”

Influence of Metal Versus Transparent Matrices on Proximal Contact Tightness of Class Ii Bulk-Fill Composite Restorations

“…Three different categories for bulk-fill composites are present according to different viscosities; low-viscosity (flowable), variably viscous and highly viscous bulk-fill resin composites. [9,10,11,19] SonicFill 2 is a novel bulkfill composite resin with a special delivery system (special handpiece that produces sonic energy) used to perform filling of cavity preparations in bulk up to 5mm by decreasing viscosity (variable viscosity). According to the manufacturer, energy from the SonicFill 2 instrument reduces the composite's viscosity (temporarily reduces the viscosity by 87%) in a way that makes it easier for the provider to inject into the tooth's preparation and adapt to Fig.…”

“…Therefore, currently, bulk-fill restoratives are clinically preferred. [9][10][11][12] This in vitro study evaluated four different matrix systems in measuring the proximal contact tightness achieved in Class II bulk-fill resin composite restorations.…”