Mechanical properties of resin cements with different activation modes

Abstract

Dual-cured cements have been studied in terms of the hardness or degree of conversion achieved with different curing modes. However, little emphasis is given to the influence of the curing method on other mechanical properties. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). Specimens were fractured using a three-point bending test. Pre-failure loads corresponding to specific displacements of the cross-head were used for flexural modulus calculation. Knoop hardness (KHN) was measured on fragments obtained after the flexural test. Tests were performed after 24 h storage at 37 degrees C. RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. No statistical difference was detected in the flexural modulus among the different groups.

Influence of ceramic thickness on mechanical properties and polymer structure of dual-cured resin luting agents

“…Although these reduced light intensities were enough to initiate the light curing reaction, they produced a continuous reduction of KHN1 with increase of ceramic thickness, and the chemical component of dual-cured luting agents did not produce significant compensation for KHN1. Nevertheless, three dual-cured resin luting agents without irradiation produced rather high KHN1, 12 similar to those with direct irradiation. This result further support these previous viewpoint that fast light polymerization can prevent the role of chemical polymerization of dual-cured resin luting agents.…”

“…Apart from thickness of restorations, the three curing modes (dual, light, and chemical) used for dual-cured resin luting agents may affect the mechanical properties [10][11][12][13]. It was believed that different brands of dual-cured resin luting 5 agent had different ratios of light/chemical catalysts.…”

Marginal adaptation of ceramic and composite inlays in minimally invasive mod cavities

“…Generally, luting composites, even of similar composition, can differ considerably in their chemical and physical characteristics [45,46], and are hence affected in different ways by light polymerization [47]. In addition the use of a highly filled and viscous composite for luting the restoration has obvious advantages since it does not flow over all surfaces and may be easily removed with a probe, spatula or floss.…”

Shear bond strength of resin cements to human dentin

“…due to an opaque core of the reconstruction. As was shown, dual-curing cements achieve an optimal degree of conversion only with additional photo activation [31][32][33]. Though not always possible, light-curing is preferable for optimal bond quality of these cements Thermocycling influenced the bonding performance of all the cements tested except RelyX ARC in both centers and RelyX Unicem in the first center (Zurich).…”