Polymerization Shrinkage, Hygroscopic Expansion, Elastic Modulus and Degree of Conversion of Different Composites for Dental Application

Abstract

Objectives: To characterize the mechanical properties of different resin-composites for dental application. Methods: Thirteen universal dentin shade composites (n = 10) from different manufacturers were evaluated (4 Seasons, Grandio, Venus, Amelogen Plus, P90, Z350, Esthet-X, Amaris, Vita-l-escence, Natural-Look, Charisma, Z250 and Opallis). The polymerization shrinkage percentage was calculated using a video-image recording device (ACUVOL—Bisco Dental) and the hygroscopic expansion was measured after thermocycling aging in the same equipment. Equal volumes of material were used and, after 5 min of relaxation, baseline measurements were calculated with 18 J of energy delivered from the light-curing unit. Specimens were stored in a dry-dark environment for 24 h then thermocycled in distilled water (5–55 °C for 20,000 cycles) with volume measurement at each 5000 cycles. In addition, the pulse-excitatory method was applied to calculate the elastic modulus and Poisson ratio for each resin material and the degree of conversion was evaluated using Fourier transform infrared spectroscopy. Results: The ANOVA showed that all composite volumes were influenced by the number of cycles (α = 0.05). Volumes at 5 min post-polymerization (12.47 ± 0.08 cm3) were significantly lower than those at baseline (12.80 ± 0.09 cm3). With regard to the impact of aging, all resin materials showed a statistically significant increase in volume after 5000 cycles (13.04 ± 0.22 cm3). There was no statistical difference between volumes measured at the other cycle steps. The elastic modulus ranged from 22.15 to 10.06 GPa and the Poisson ratio from 0.54 to 0.22 with a significant difference between the evaluated materials (α = 0.05). The degree of conversion was higher than 60% for all evaluated resin composites.

The Effect of a Green Smoothie on Microhardness, Profile Roughness and Color Change of Dental Restorative Materials

“…All materials were of A2 shade. The composition of tested materials as provided by their respective manufacturers and the available literature [ 25 , 26 , 27 , 28 ] is shown in Table 1 .…”

Influence of Enamel Exposure to Acidic Drink on Shear Bond Strength of Different Fissure Sealants

“…Nowadays fissure sealants are widespread and there are several commercial products available for clinicians with a quite different polymerization shrinkage, degree of conversion, and biomechanical properties. These variables related to the composition of the materials could influence the results of the present report [ 49 ]. This concern should be evaluated in future studies.…”

Effect of Resin Cement at Different Thicknesses on the Fatigue Shear Bond Strength to Leucite Ceramic

“…19 On the other hand, marginal discrepancy and lower bond strength caused by thicker resinous materials could be more evident in complex geometry, such as crowns, due to high polymerization shrinkage of the cement. 20,21 In addition, a thicker cement film exposes more polymeric material to the oral environment, increasing its susceptibility to the degradation. [22][23][24] It was reported that the acceptable cement thickness for dental restorations should be up to 120 μm.…”