Polishing Methods' Influence on Color Stability and Roughness of 2 Provisional Prosthodontic Materials

Abstract

Purpose: To evaluate the roughness and color change of a conventional acrylic resin and a bis-acryl resin, submitted to different types of polishing and exposed to a staining solution. Materials and Methods: One hundred specimens were manufactured from an autopolymerizing conventional acrylic resin (Duralay, shade 66) (n = 50) and a bis-acryl resin (Protemp 4, shade A3) (n = 50) according to the manufacturers' instructions. Specimens were subdivided into 10 groups (n = 10), according to the type of resin and polishing method, including no-polishing (control groups for acrylic resin [tungsten bur finishing] and bis-acryl resin [cotton and alcohol]), Enhance System, Edenta kit, Labordental kit, and sandpaper. The specimens were immersed in a staining solution (coffee at 60°C) for 7 days. Surface roughness was evaluated before the first immersion (baseline -Ra1) and after 7 days (Ra2). The color change (E) was determined after 24 hours (E1) and 7 days (E2), by CIE L * a * b * scale. Data were statistically analyzed with 3-way ANOVA for repeated measures test and Tukey test (α = 0.05). Results: According to 3-way ANOVA test, material, polishing techniques, and polishing*material factors exhibited statistically significant influence (p < 0.0001) on the roughness, and, for color change, material, polishing techniques, time, polishing*material, and material*time factors were statistically significant (p < 0.0001). The polishing techniques successfully reduced the surface roughness of acrylic resin groups, when compared to control (p < 0.001), but for bis-acryl resin, results were not different from the control group (Enhance: p = 0.954, Edenta: p = 0.866, sandpaper: p = 0.366, Labordental: p = 0.945). Surface roughness was not affected by the immersion in staining solution for 7 days. Color change of acrylic resin groups after 24 hours and 7 days of immersion exhibited a clinically acceptable value ( E < 3.7) with the exception of the Enhance group, and all bis-acryl resin groups exhibited a clinically unacceptable color change value ( E > 3.7) independent of polishing technique and time interval (E1 and E2). Conclusions: Roughness of both materials was similar when the polishing techniques studied were performed, although Ra values were superior to the clinically acceptable values (0.20 µm), and were not affected by the immersion protocol studied; however, when esthetics are critical, the selection of material type is more important than the surface treatment technique used, and bis-acryl resin was more susceptible to clinically unacceptable color change after immersion in a staining solution.Provisional restorations should be prepared to reproduce and maintain the tooth's natural properties, such as size, position, shape, color, surface texture, and dental translucency. 1-3 Currently, with the development of new dental materials, professionals have many options to manufacture provisional restorations. These options include poly methyl methacrylate (PMMA), poly ethyl methacrylate (PEMA), polyvinyl ethyl methacrylate (P...

Pit and fissure nanocomposite sealants reinforced with organically modified montmorillonite: A study of their mechanical properties, surface roughness and color stability

“…The importance of color stability in dental restorative materials due to esthetic reasons is reflected by many studies dedicated to the evaluation of color changes caused by discoloration factors, polishing and bleaching treatments etc [49][50][51][52] . Several reports regarding restorative materials claim that color alteration is perceptible when ΔE>1, clinical acceptable values are limited to ΔE<3.3 [53][54][55] .…”

Cinnamaldehyde is a biologically active compound for the disinfection of removable denture: blinded randomized crossover clinical study

“…The spectrophotometer was calibrated according to the calibration standard provided by the manufacturer. Three measurements were made for each specimen, and the mean values were registered for the parameters "L," "a," and "b," where "L" refers to the brightness, "a" means redness to greenness, and "b" yellowness to blueness [26,27].…”

“…In which ΔL, Δa, and Δb refer to the difference among the values of L*, a*, and b* between the initial color measurement and the measurement after the 14-day experiment, for each tested solution. Quantification of ΔE values was performed using the National Bureau of Standards (NBS), with NBS units of color difference (NBS units = ΔE*0.92) [13,[26][27][28]. A limit of ΔE ≤ 3.7 was considered clinically acceptable [27]..…”

“…Quantification of ΔE values was performed using the National Bureau of Standards (NBS), with NBS units of color difference (NBS units = ΔE*0.92) [13,[26][27][28]. A limit of ΔE ≤ 3.7 was considered clinically acceptable [27].. Surface roughness analysis (Ra) was performed on the non-contact optical profilometer (CCI MP, Taylor Hobson, England).…”

“…A 0.25 mm cutoff was used with a 50x lens, 0.4 numerical aperture, and × 1 scan speed in xyz mode. Three measurements were performed for each specimen (n = 16), with the final roughness (μm) obtained as the average of the three points of each specimen [16,27].…”