Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, Turkey.
Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, Turkey.
J Prosthet Dent. 2021 Jul;126(1):129.e1-129.e7. doi: 10.1016/j.prosdent.2021.03.024. Epub 2021 May 6.
Sintering holding times and aging conditions may affect the optical, mechanical, and structural properties of polychromatic multitranslucent zirconia. However, a consensus on the ideal sintering condition for this material is lacking.
The purpose of this in vitro study was to investigate the effect of different sintering holding and autoclave aging times on the flexural strength (FS), grain size, and translucency parameter (TP) of a translucent zirconia.
Sixty bar-shaped and 60 rectangular-shaped specimens were prepared from computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia blocks and split into 2 groups to be sintered at 1550 °C for different holding times (regular: 2 hours, prolonged: 5 hours). The specimens were then divided into 3 subgroups and subjected to aging processes (control, aging for 60 minutes, aging for 120 minutes). FS values were obtained by using a 3-point bend test and Weibull analysis was conducted. Grain size evaluations were performed by using scanning electron microscope (SEM) observations. TP was measured with a spectrophotometer. Statistical evaluation included the Kolmogorov-Smirnov, 2-way ANOVA, and Tukey HSD tests (α=.05).
The sintering procedure, aging, and their interaction significantly influenced the TP (P<.05). FS values and grain sizes were affected by aging only (P<.001). Both aging times resulted in reduced FS and increased grain sizes. Prolonged sintering in combination with 120 minutes of aging negatively affect the TP scores (P<.05).
FS values were similar under regular and prolonged sintering. Prolonged sintering led to a decrease in translucency after 120 minutes of aging. Steam autoclave aging can affect the optical and mechanical properties of translucent zirconia.
烧结保温时间和时效条件可能会影响多色半透明氧化锆的光学、机械和结构性能。然而，对于这种材料的理想烧结条件尚未达成共识。
本体外研究的目的是研究不同的烧结保温时间和高压蒸汽灭菌老化时间对半透明氧化锆的弯曲强度（FS）、晶粒尺寸和透光率参数（TP）的影响。
从 CAD-CAM 氧化锆块制备 60 个条形和 60 个矩形试件，并分为 2 组，在 1550°C 下烧结不同的保温时间（常规：2 小时，延长：5 小时）。然后将试件分为 3 个亚组，并进行老化处理（对照、老化 60 分钟、老化 120 分钟）。通过三点弯曲试验获得 FS 值，并进行 Weibull 分析。使用扫描电子显微镜（SEM）观察进行晶粒尺寸评估。使用分光光度计测量 TP。统计评估包括 Kolmogorov-Smirnov、2 因素方差分析和 Tukey HSD 检验（α=.05）。
烧结程序、时效及其相互作用显著影响 TP（P<.05）。FS 值和晶粒尺寸仅受时效影响（P<.001）。两种时效时间均导致 FS 值降低和晶粒尺寸增大。延长烧结时间并结合 120 分钟的时效会降低 TP 评分（P<.05）。
在常规和延长烧结下，FS 值相似。延长烧结后，在 120 分钟时效后透光率降低。蒸汽高压灭菌时效会影响半透明氧化锆的光学和机械性能。
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