Senior Research Associate, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
Assistant Professor, Istinye University, Faculty of Dentistry, Department of Prosthodontics, İstanbul, Turkey; Visiting Researcher, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
J Prosthet Dent. 2024 Jul;132(1):260-266. doi: 10.1016/j.prosdent.2022.06.006. Epub 2022 Aug 20.
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.
The purpose of this in vitro study was to compare the effect of simulated brushing and CTC on the surface roughness (R) and stainability of computer-aided design and computer-aided manufacturing (CAD-CAM) denture base materials and a heat-polymerized denture base material.
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). R 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. R and color coordinates were measured after each interval. Color differences (ΔE) 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 (α=0.05).
The time interval had a significant effect on R (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 ΔE (P=.016). The only significant difference in ΔE values was observed between M-PM and CV after all treatments were completed (P=.029).
Brushing increased the R 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.
预聚物加工的义齿基托已变得流行。然而，关于模拟刷牙和咖啡热循环（CTC）对其表面粗糙度和染色性的影响的信息尚缺乏。
本体外研究的目的是比较模拟刷牙和 CTC 对 CAD-CAM 义齿基托材料和热聚合义齿基托材料的表面粗糙度（R）和染色性的影响。
从 3 种 CAD-CAM 义齿基托树脂（AvaDent、AV；Merz M-PM、M-PM；和 Polident d.o.o、Poli）和一种热聚合聚甲基丙烯酸甲酯树脂（Promolux、CV）中制备了 40 个圆盘形试件（n=10）。常规抛光后，使用非接触式轮廓仪测量试件的 R 值。使用分光光度计在灰色背景上测量颜色坐标。然后，将试件连续进行 20000 次模拟刷牙、5000 次 CTC 和另外 10000 次刷牙循环。每次间隔后测量 R 和颜色坐标。使用 CIEDE2000 公式计算色差（ΔE），并使用双向方差分析和 Tukey 诚实显著差异检验（α=0.05）对数据进行分析。
时间间隔对 R 有显著影响（P<.001），因为刷牙循环的 R 值高于基线和 CTC 后的 R 值（P<.001）。然而，刷牙循环之间（P=.143）和基线与 CTC 之间（P=.994）的差异不显著。材料类型和时间间隔之间的相互作用对 ΔE 有显著影响（P=.016）。在完成所有处理后，仅观察到 M-PM 和 CV 之间的 ΔE 值有显著差异（P=.029）。
与基线相比，所有材料的 R 值在刷牙后均增加。所有材料在刷牙和 CTC 过程中均表现出相似的染色性。然而，所有处理完成后，M-PM CAD-CAM 义齿基托树脂的颜色变化大于传统义齿基托树脂。考虑到报告的可感知性和可接受性阈值，所有颜色变化均可视为临床微小变化。
