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  • Küçük Resim
    Öğe
    Effect of simulated brushing and disinfection on the surface roughness and color stability of CAD-CAM denture base materials
    (Elsevier Science, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Akay, Canan; Atalay, Sevda; Silva de Paula, Marcella; Schimmel, Martin; Yılmaz, Burak
    Purpose: To evaluate the effect of simulated brushing and chemical disinfection on the surface roughness and color stability of CAD-CAM denture base materials and to compare with those of a heat-cured denture base material. Material and methods: Disk-shaped specimens (Ø 10mm × 2 mm) were prepared from 3 CAD-CAM denture base resins (AvaDent, Ava; Merz M-PM, Merz; Polident d.o.o, Poli) and a heat-cured polymethylmethacrylate resin (Promolux, Conv) (n = 30). After polishing, baseline surface roughness (Ra) and color coordinates were measured. The measurements were repeated after 20000 cycles of simulated brushing, and the specimens were divided into 3 groups according to disinfection protocol (distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet) (n = 10). After 9 cleaning cycles over a period of 20 days, Ra and color coordinates were remeasured. Color differences (?E00) were calculated by using CIEDE2000 formula. One-way analysis of vari- ance (ANOVA) and pairwise t-tests were used to analyze Ra and ?E00 data, while repeated measures ANOVA test was used to compare baseline, after brush, and after disinfection Ra values (? = 0.05). Results: Brushing did not affect the Ra values of tested materials (P ? .08). Both before and after brushing, Merz and Conv had higher Ra values than Poli and Ava (P < .001). Among disinfectants, effervescent tablet led to the lowest Ra for Merz (P = .003) and the highest Ra for Poli (P ? .039). Only NaOCl resulted in significant dif- ferences among the Ra of materials (P < .001), as Merz and Conv had higher Ra values than Poli (P ? .002). Repeated measures ANOVA revealed that effervescent tablet disinfection of Merz led to lower Ra values than those of baseline and after brushing (P ? .042). After brushing, Ava and Conv had higher ?E00 values compared with Merz and Poli (P ? .015). When compared with other disinfection protocols, effervescent tablet led to higher ?E00 values for Merz and Poli (P < .001). Significant differences were observed among materials when NaOCl was used; Conv had higher ?E00 values than Ava and Merz (P = .004). Conclusions: Brushing did not increase the surface roughness of materials. Disinfection protocol’s effect on the surface roughness varied. The effect of brushing on the color of materials varied; color of Ava and Conv was affected from brushing more than the other materials. Color stability of materials varied depending on the disinfection protocol. Effervescent tablet caused higher color change with Merz and Poli compared with other disinfectants. NaOCl led to small color change for Poli, Ava, and Merz materials.
  • Küçük Resim
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    Surface roughness and stainability of CAD-CAM denture base materials after simulated brushing and coffee thermocycling
    (Elsevier, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Atalay, Sevda; Silva de Paula, Marcella; Fonseca, Manruque; Schimmel, Martin; Yılmaz, Burak
    Statement of problem: Denture bases machined from prepolymerized materials have become popular. However, information on the effect of simulated brushing and coffee thermocycling (CTC) on their surface roughness and stainability is lacking. Purpose: The purpose of this in vitro study was to compare the effect of simulated brushing and CTC on the surface roughness (Ra) and stainability of computer-aided design and computer-aided manufacturing (CAD-CAM) denture base materials and a heat-polymerized denture base material. Material and methods: Forty disk-shaped specimens were prepared from 3 CAD-CAM denture base resins (AvaDent, AV; Merz M-PM, M-PM; and Polident d.o.o, Poli) and a heat-polymerized polymethylmethacrylate resin (Promolux, CV) (n=10). Ra values of the specimens were measured by using a noncontact profilometer after conventional polishing. The color coordinates were also measured over a gray background with a spectrophotometer. Specimens were then consecutively subjected to simulated brushing for 20 000 cycles, CTC for 5000 cycles, and another 10 000 brushing cycles. Ra and color coordinates were measured after each interval. Color differences (?E00) were calculated by using the CIEDE2000 formula, and the data were analyzed by using 2-way analysis of variance and Tukey honestly significant difference tests (?=0.05). Results: The time interval had a significant effect on Ra (P<.001) as brushing cycles resulted in higher values than those at baseline and after CTC (P<.001). However, the differences between brushing cycles (P=.143) and between the baseline and after CTC (P=.994) were not significant. The interaction between the material type and time interval was significant for ?E00 (P=.016). The only significant difference in ?E00 values was observed between M-PM and CV after all treatments were completed (P=.029). Conclusions: Brushing increased the Ra of all materials when compared with the baseline. All materials showed similar stainability throughout the brushing and CTC processes. However, M-PM CAD-CAM denture base resin underwent a greater color change after all treatments were completed than conventional denture base resin. All color changes can be considered clinically small, considering reported perceptibility and acceptability thresholds.