Effect of Different Polymerization Times on Color Change, Translucency Parameter, and Surface Hardness of Bulk-Fill Resin Composites

Abstract

Background: Polymerization plays an important role in the optical and mechanical properties resin composite materials. Aim: The current study aimed to evaluate the effect of different polymerization times on the color change, translucency parameter (TP), and surface hardness of resin composites after thermocycling. Materials and Methods: Microhybrid resin composite (Filtek Z250; used in the control group) and bulk-fill resin composites (Filtek One Bulk-Fill Restorative, Tetric EvoCeram Bulk-Fill, and Tetric N-Ceram Bulk-Fill) were used. Each bulk-fill composite was placed as a single layer. Polymerization of the bulk-fill composites in the first group was completed in 20 s, and that in the second group was completed in 40 s (n = 10). Filtek Z250's polymerization was completed with 2 mm (20 s) + 2 mm (20 s). The color change (ΔE 00) and translucency parameter (TP 00) were calculated using the CIEDE2000 formula. Before and after thermocycling, the TP and surface hardness values were measured. The data were analyzed using one- and two-way analysis of variance, paired-samples t-test, and Tukey's test (P < 0.05). Results: After thermocycling, the ΔE 00 values of the resin composite samples were 1.66–2.56. Compared to the control group, the Filtek One Bulk-Fill 20 s group exhibited the lowest color change values. The Filtek Z250 group exhibited lower TP and significantly higher microhardness values than the other bulk-fill resin groups before and after thermocycling (P < 0.05). There were no observed differences in the Tetric N-Ceram and Tetric EvoCeram groups before and after thermocycling. Conclusion: Under the conditions of 10,000 thermal cycles, different curing times did not affect the color change and hardness values of the bulk-fill materials. However, differences were observed among the composite materials. After thermocycling, the surface hardness and TP values decreased in all the resin composites. Depending on the material content, effective results can be obtained from the 20 s polymerization of bulk-fill resin composites.

Translucency of bulk‐fill composite materials: A systematic review

“…Bin Nooh et al, Gonder and Fidan, and Kim et al 14,32,33 for example obtained comparable values but lower than those of Al Senan and Al-Nahedh and Lopes et al 31,35 This discrepancy may be ascribed to the 24 h storage in distilled water performed by the first group of studies and not from the second one. Water storage and specimens' hydration could have therefore affected materials' translucency.…”

“…Reveal HD Bulk-Fill is characterized by HD filler technology, which allows light to pass through the material, while Tetric N-Ceram is prepared with Assencio filler technology that experimentally increases its opacity. 32 Indeed, Tetric composites contain a wide variety of filler types, among them: barium aluminum silicate glass (an "isofiller"), ytterbium fluoride, spherical mixed oxide, 33 and a mightier photoinitiator than CQ to increase curing depth, called Ivocerin. 11,60 In the study of Al-Senan and Al-Nahedh, 31 Tetric N Ceram Bulk-Fill showed higher TP values than the other materials tested, probably due to the above-mentioned ytterbium trifluoride filler (also incorporated in Filtek One Bulk-Fill).…”

“…Many studies investigated mechanical and optical properties of BFs, nevertheless, few studies 10,14,[31][32][33][34][35][36][37][38][39][40] focused on BF's translucency.…”

Study on the mechanical and aging properties of an antibacterial composite resin loaded with fluoride-doped nano-zirconia fillers

“…Thermal cycling was the most common approach that applied to simulate the aging of dental materials during temperature fluctuations that occur in the mouth in previous studies (Gale and Darvell, 1999;Tavas et al, 2023). It was carried out at temperatures equivalent to the intraoral temperature, ranging from 5 °C to 55 °C, and 10,000 cycles might be equivalent to 1 year (Gonder and Fidan, 2022). Color change (ΔE00 value) and microhardness of the experimental CRs affected by aging were presented in Table 5 and Table 6.…”