Effect of Ceramic Veneer Opacity and Exposure Time on the Polymerization Efficiency of Resin Cements

Abstract

The objective of this study was to determine the degree of conversion (DC), hardness (H), and modulus of elasticity (E) of a dual-cured resin cement, a light-cured resin cement, and a flowable resin cured through opaque or translucent ceramic with different exposure times. RelyX ARC (dual), RelyX Veneer (light-cured), and Filtek Z350 Flow resin specimens 0.5 mm thick were cured for 40, 80, and 120 seconds through 1-mm thick translucent or opaque feldspathic ceramic disks (n=10). The specimens were stored at 37°C for 24 hours. Half of each specimen was used to test the DC and the other half to test H and E. The DC was determined in a Fourier transform infrared spectrometer in absorbance mode at peaks of 1638 cm(-1) and 1610 cm(-1). H and E were determined using nanoindentation with one loading cycle and a maximum load of 400 mN. The data were analyzed with three-way analysis of variance (ANOVA), the Games-Howell test, and the Pearson correlation test (α=0.05). Statistically significant differences were found for all three factors (material, opacity, and exposure time), as well as interaction between them. The opaque ceramic resulted in lower DC, H, and E than the translucent ceramic for an exposure time of 40 seconds. An exposure time of 120 seconds resulted in a similar DC for all materials, irrespective of the opacity of the ceramic. Materials cured for 120 seconds had higher H and E than those cured for 40 seconds. The exposure time and opacity of the ceramic exerted an influence on the DC, H, and E of the materials evaluated.

Effect of Ceramic Thickness and Shade on Mechanical Properties of a Resin Luting Agent

“…According to Meng et al, EM exhibited a strong correlation to the KHN for the dual‐cured resin cements evaluated. This data could explain the fact that EM and KHN were decreased continuously with the increase of ceramic thickness under dual‐cured cement and a light‐cured composite as well. In addition, in this study the self‐curing components of dual‐cured resin cements did not provide sufficient compensation when a thicker ceramic was used.…”

“…Yet, the darker the ceramic, the more critical it is to achieve an optimal photopolymerization of the material . Studies observed lower resin cement microhardness values and degree of conversion, depending on the restoration shade tested . In fact, degree of conversion and hardness of composite materials can be associated with each other …”

Influence of light irradiation on Vickers hardness of dual-cure cement polymerized under restorations

“…It was reported that the polymerization efficiency of dual-cure resins was affected by numerous factors: irradiation duration 24) , light intensity 25) , light transmission 26,27) , and ceramic shade 26) and thickness 28,29) . Specifically, a translucent ceramic which allowed more light to transmit through the material, as compared to an opaque ceramic, resulted in improved mechanical properties of dual-cure resin cement placed under the restorative material 30) .…”

“…In the present study, the use of 3-mm-thick ZR restorations could be deemed comparatively thick in consideration of the restoration thicknesses selected and employed in other studies 26,27,30) . Nonetheless, the high light intensity of the light curing unit (900 mW/cm 2 ) 25) , coupled with the high light transmission property of ZR 27) , enabled the polymerization of dual-cure resin cement placed under the ZR restoration.…”

Study of lumineers' interfaces by means of optical coherence tomography

“…The types of cements, adhesives and the treatment given to the tooth surface and ceramics are some of the most discussed topics in several studies. The adaptation of the lumineer on the tooth is also important to the success of the treatment [5].…”