Color assessment of resin composite by using cellphone images compared with a spectrophotometer

de Bragança Rafaella Mariana Fontes,Moraes Rafael Ratto,Faria-e-Silva André Luis 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.2

Objectives: This study assessed the reliability of digital color measurements using images of resin composite specimens captured with a cellphone. Materials and Methods: The reference color of cylindrical specimens built-up with the use of resin composite (shades A1, A2, A3, and A4) was measured with a portable spectrophotometer (CIELab). Images of the specimens were obtained individually or pairwise (compared shades in the same photograph) under standardized parameters. The color of the specimens was measured in the images using RGB system and converted to CIELab system using image processing software. Whiteness index (WID) and color differences (ΔE00) were calculated for each color measurement method. For the cellphone, the ΔE00 was calculated between the pairs of shades in separate images and in the same image. Data were analyzed using 2-way repeated-measures analysis of variance (α = 0.05). Linear regression models were used to predict the reference ΔE00 values of those calculated using color measured in the images. Results: Images captured with the cellphone resulted in different WID values from the spectrophotometer only for shades A3 and A4. No difference to the reference ΔE00 was observed when individual images were used. In general, a similar ranking of ΔE00 among resin composite shades was observed for all methods. Stronger correlation coefficients with the reference ΔE00 were observed using individual than pairwise images. Conclusions: This study showed that the use of cellphone images to measure the color difference seems to be a feasible alternative providing outcomes similar to those obtained with the spectrophotometer.

Bond strength of self-adhesive resin cements to composite submitted to different surface pretreatments

dos Santos, Victor Hugo,Griza, Sandro,de Moraes, Rafael Ratto,Faria-e-Silva, Andre Luis The Korean Academy of Conservative Dentistry 2014 Restorative Dentistry & Endodontics Vol.39 No.1

Objectives: Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. Material and Methods: Composite discs were subject to one of six different surface pretreatments: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice ($1mm^2$ diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Results: Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions: Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate.

Bond strength of self-adhesive resin cements to composite submitted to different surface pretreatments

Victor Hugo dos Santos,Sandro Griza,Rafael Ratto de Moraes,André Luis Faria-e-Silva 대한치과보존학회 2014 Restorative Dentistry & Endodontics Vol.39 No.1

Objectives: Extensively destroyed teeth are commonly restored with composite resinbefore cavity preparation for indirect restorations. The longevity of the restorationcan be related to the proper bonding of the resin cement to the composite. This studyaimed to evaluate the microshear bond strength of two self-adhesive resin cements tocomposite resin. Material and Methods: Composite discs were subject to one of sixdifferent surface pretreatments: none (control), 35% phosphoric acid etching for 30seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane+ adhesive (n = 6). A silicone mold containing a cylindrical orifice (1 mm2 diameter)was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.)self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesivecement cylinders were submitted to shear loading. Data were analyzed by two-wayANOVA and Tukey’s test (p < 0.05). Results: Independent of the cement used, the PA+ Silane + Adhesive group showed higher microshear bond strength than those ofthe PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions: Pretreatments of the composite resin surface might have an effect onthe bond strength of self-adhesive resin cements to this substrate.

Physicochemical characterization of two bulk fill composites at different depths

Grazioli Guillermo,Cuevas-Suárez Carlos Enrique,Nakanishi Leina,Francia Alejandro,Moraes Rafael Ratto de 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.3

Objectives This study analyzed the physical-chemical behavior of 2 bulk fill resin composites (BFCs; Filtek Bulk Fill [FBF], and Tetric-N-Ceram Bulk Fill [TBF]) used in 2- and 4-mm increments and compared them with a conventional resin composite (Filtek Z250). Materials and Methods Flexural strength and elastic modulus were evaluated by using a 3-point bending test. Knoop hardness was measured at depth areas 0–1, 1–2, 2–3, and 3–4 mm. The translucency parameter was measured using an optical spectrophotometer. Real-time polymerization kinetics was analyzed using Fourier transform infrared spectroscopy. Results Flexural strength was similar among the materials, while TBF showed lower elastic modulus (Z250: 6.6 ± 1.3, FBF: 6.4 ± 0.9, TBF: 4.3 ± 1.3). The hardness of Z250 was similar only between 0–1 mm and 1–2 mm. Both BFCs had similar hardness until 2–3 mm, and showed significant decreases at 3–4 mm (FBF: 33.45 ± 1.95 at 0–1 mm to 23.19 ± 4.32 at 3–4 mm, TBF: 23.17 ± 2.51 at 0–1 mm to 15.11 ± 1.94 at 3–4 mm). The BFCs showed higher translucency than Z250. The polymerization kinetics of all the materials were similar at 2-mm increments. At 4-mm, only TBF had a similar degree of conversion compared with 2 mm. Conclusions The BFCs tested had similar performance compared to the conventional composite when used in up to 2-mm increments. When the increment was thicker, the BFCs were properly polymerized only up to 3 mm. Objectives This study analyzed the physical-chemical behavior of 2 bulk fill resin composites (BFCs; Filtek Bulk Fill [FBF], and Tetric-N-Ceram Bulk Fill [TBF]) used in 2- and 4-mm increments and compared them with a conventional resin composite (Filtek Z250). Materials and Methods Flexural strength and elastic modulus were evaluated by using a 3-point bending test. Knoop hardness was measured at depth areas 0–1, 1–2, 2–3, and 3–4 mm. The translucency parameter was measured using an optical spectrophotometer. Real-time polymerization kinetics was analyzed using Fourier transform infrared spectroscopy. Results Flexural strength was similar among the materials, while TBF showed lower elastic modulus (Z250: 6.6 ± 1.3, FBF: 6.4 ± 0.9, TBF: 4.3 ± 1.3). The hardness of Z250 was similar only between 0–1 mm and 1–2 mm. Both BFCs had similar hardness until 2–3 mm, and showed significant decreases at 3–4 mm (FBF: 33.45 ± 1.95 at 0–1 mm to 23.19 ± 4.32 at 3–4 mm, TBF: 23.17 ± 2.51 at 0–1 mm to 15.11 ± 1.94 at 3–4 mm). The BFCs showed higher translucency than Z250. The polymerization kinetics of all the materials were similar at 2-mm increments. At 4-mm, only TBF had a similar degree of conversion compared with 2 mm. Conclusions The BFCs tested had similar performance compared to the conventional composite when used in up to 2-mm increments. When the increment was thicker, the BFCs were properly polymerized only up to 3 mm.