Search Results (6)

This study evaluated the optical and mechanical properties of two single-shade composite resins compared with a conventional multi-shade composite. Omnichroma (OM), Metafil Bulk Fill ONE (BO), and Filtek Z350XT (Z350) were tested. Color adjustment was assessed using A3, B1, and C4 background cavities, and ΔE00 values were calculated. The translucency parameter (TP) was measured, and the flexural strength, flexural modulus, and depth of cure (B/T ratio) were determined. OM and BO showed better color adjustment performance on brighter (B1) backgrounds and decreased matching on darker (C4) ones. OM maintained stable color adjustment across cavity depths, while BO showed improved adjustment in shallower cavities. Both exhibited higher TP values than Z350. The control group (Z350) had the highest flexural strength and modulus, though BO’s flexural strength was comparable. OM and BO showed sufficient mechanical strength and a greater depth of cure compared to Z350. Our study indicated that the one-shade composite resins OM and BO exhibited better color adjustment performance compared to conventional composite resins due to the influence of the surrounding shades, with a better adjustment ability on brighter backgrounds. Additionally, OM and BO demonstrated sufficient strength and a higher depth of cure compared to the control group. Full article

This study aims to evaluate the shrinkage, degree of conversion, water sorption and solubility, and mechanical properties of a newly developed one-shade universal composite and compare it with five other commercially available universal composites with one or multiple shades. Our proprietary resin and filler technologies developed the experimental one-shade universal composite (Experimental). Volumetric shrinkage was determined using the AcuVol video imaging method (n = 5). Degree of conversion was measured using FTIR (n = 5). Water sorption and solubility (15 × 1 mm, n = 5) and flexural strength and modulus (2 × 2 × 25 mm, n = 5) were measured according to ISO-4049. Diametral tensile strength (6 × 3 mm, n = 8) was tested according to ANSI/ADA-Specification #27. The data were analyzed using one-way ANOVA and post hoc Tukey tests (p ≤ 0.05). Like Clearfil Majesty ES-2, Experimental showed lower or significantly lower volumetric shrinkage than other composites. Experimental exhibited a considerably higher degree of conversion and high flexural modulus compared to the others. However, there are no significant differences in flexural strength among these universal composites except for Omnichroma. Experimental also displayed significantly higher diametral tensile strength than the others, except similar to Filtek Supreme Ultra. Experimental has the lowest values of water sorption and solubility among the composites tested. The experimental universal composite demonstrated improved or comparable physical and mechanical properties compared to commercially available one-shade universal composites or multi-shade conventional universal composites, which is of significance for the clinical performance of dental restorations. Full article

Objective: The aim of this study was to compare the surface roughness of a conventional composite resin, a one-shade universal composite resin, and a group-shade universal composite resin after bleaching. Methods: A conventional composite resin, Clearfill, and the universal composite resins Omnichroma and Optishade were prepared into discs (2 × 8 mm), with a total of 90 discs. Each group (30) contained three different groups, including a control (n10), coloured with CHX (n10), and after bleaching (n10). The surface roughness of group discs was measured with a 3D profilometer. ANOVA and Kruskal–Wallis Tests were used to analyse data. Analyses were performed in the SPSS programme. Results: Significant Ra values were obtained between subgroups (p < 0.05). Comparisons of surface roughness after discolouring were performed with the control group; the highest surface roughness value (p > 0.05) was found for Optishade after bleaching compared to the control group. The Optishade composite resin showed the highest initial surface roughness value (p > 0.05), and after discolouration followed by bleaching, the Clearfill composite resin showed the highest surface roughness value (p > 0.05). Conclusions: Both immersion and bleaching applications cause surface roughness. As a result, it was determined that the composite resin content has a significant effect on the surface roughness in discolouring and bleaching processes. Full article

The aim of the study was to evaluate changes in the degree of C=C conversion (DC%), chemical structure, optical properties and roughness of one-shade composites before/after photoaging. Τhe one-shade materials tested were Charisma Topaz One (CHT), Clearfil Majesty ES-2 Universal (MES), Essentia Universal (ESU) and Omnichroma (OMN), with G-aenial Anterior (CNA) serving as control. Specimens (2 mm thickness) were prepared and tested for DC% and chemical structure (ATR–FTIR spectroscopy), optical properties (L*a*b*–ΔΕ, translucency parameter–TP, opalescence parameter–OP, contrast ratio–CR and total transmittance–TT by UV–Vis spectroscopy) and roughness (Sa, Sz, Sdr, Sds and Sc by optical profilometry) before and after photoaging (Xe-arc weatherometer). Significant differences were found in DC% between top–bottom surfaces (ESU, OMN before; ESU, CNA after). Photoaging improved DC%, reduced ester peaks implying photodegradation, reduced L* (CHT, OMN, CNA), a* (CHT, CNA), b* (OMN, CNA), TP (all, except for MES), OP (only MES), CR (only MES, but an increase in CNA) and TT (CHT, OMN). OMN, CNA and MES demonstrated ΔΕ > 3.3. Photoaging significantly increased all roughness parameters in all materials, except for MES (Sz, Sdr, Sc) and OMN (Sdr). Although listed in the same group, significant differences were found in one-shade composites before and after photoaging. Several products were strongly affected by photoaging, demonstrating evidence of photodegradation, an increased roughness and color changes exceeding the clinically acceptable levels. Full article

The purpose of this study was to evaluate the color stability of repaired aesthetic restorative resin matrix materials after immersion in coffee and the effect of polishing systems after staining. One hundred and eighty cylindrical discs (8 mm × 2 mm) were prepared using a conventional nano-fill resin composite (Clearfil Majesty Esthetic A2 shade) with round cavities (3 × 1 mm). Cavities were repaired by three resin composite materials: Clearfil Majesty Esthetic A2 shade, one-shaded nano-fill resin composite (Omnichroma) and group-shaded nano-hybrid resin composite (Optishade, medium shade). Each group was polished with three polishing systems (n = 20); aluminum oxide (Soflex Spiral Wheels, 3M ESPE), silicon carbide (Occlubrush, Kerr, CA, USA) and diamond particulate (Twist Dia Spiral Wheels, Kuraray, Okayama, Japan). Color change (ΔE₀₀) measurements were performed with a spectrophotometer at the baseline. Half of the polished samples were either kept in distilled water or immersed in coffee for 15 days, and color measurements were repeated before and after polishing. Statistical analysis was performed using the Kruskal–Wallis test. Repaired samples showed different color correspondence values in all groups. All three restorative materials showed significant color changes (ΔE₀₀) after immersion in coffee (p ≤ 0.05). Repolishing of stained samples showed color improvement values in all groups. The content of the polishing system played an important role in removing the stains. Full article

(1) Background: This study aimed to determine the effect of repeated pre-polymerization heating on the color and translucency of a one-shaded resin-based composite and to evaluate whether the heating cycles affect its color stability. (2) Methods: Fifty-six samples of 1-mm thickness were fabricated from Omnichroma (OM) after applying different heating cycles (for one, five, and ten times at 45 °C) before polymerization (n = 14/group) and afterwards were stained with a yellow dye solution. CIE L*, a*, b*, C*, h° coordinates were recorded, and color differences, whiteness, and translucency were calculated, before and after staining. (3) Results: Heating cycles significantly influenced the color coordinates, WID₀₀, and TP₀₀ of OM being higher after one heating cycle and decreasing as the number of heating cycles increased. The color coordinates, WI_D, and TP₀₀ after staining significantly differed for each group. The color and whiteness differences calculated after staining exceeded the acceptability thresholds for all groups. The color and whiteness variations after staining were clinically unacceptable. (4) Conclusions: Repeated pre-polymerization heating induces a clinically acceptable color and translucency change to OM. Although the color changes resulting after staining are clinically unacceptable, increasing the number of heating cycles up to ten times slightly reduces the color differences. Full article