King Fahad Hospital, Ministry of Health, Saudi Arabia.
Advanced Education in Esthetic and Operative Dentistry Program, Department of Prosthodontics, School of Dental Medicine, Tufts University, Boston, Massachusetts, USA.
Am J Dent. 2021 Apr;34(2):91-96.
To evaluate and compare the flexural strength of three CAD-CAM glass-ceramic materials and to investigate the effect of various surface treatments on their flexural strength.
120 rectangular specimens were fabricated from three different types of CAD-CAM ceramic blocks and were divided into three groups: zirconia-reinforced lithium silicate (Celtra Duo, Group 1), leucite-reinforced glass-ceramic (IPS Empress CAD, Group 2), and lithium disilicate ceramic (IPS e.max CAD, Group 3). Dimensions of the specimens were standardized to 14.5x12.5 mm and 1.5 mm thickness. Specimens in each group were randomized into four subgroups. The first subgroup (NS) did not undergo any surface treatment; the second subgroup (P) underwent polishing only; the third subgroup (G) underwent glazing only; and the fourth subgroup (PG) underwent both polishing and glazing surface treatments. Biaxial flexural strength (FS) testing was performed until fracture occurred; FS was calculated in MPa. All analyses were performed using SPSS version 24.
Group NS2 showed the lowest FS (89.34 ± 25.30 MPa). Group PG3 showed a significantly higher FS (365.38 ± 52.52 MPa) than Group P3 (268.15 ± 48.34). There was a statistically significant difference among the material groups for each surface treatment: IPS e.max CAD showed the highest FS, which was significantly greater than that of both Celtra Duo and IPS Empress CAD. The combination of polishing and glazing surface treatment resulted in significantly higher flexural strength than polishing alone for all three materials tested. For each material, no significant difference was found between the following surface treatments: control and polishing-only surface treatments; glazing-alone and the combination of polishing and glazing surface treatments. For each surface treatment, Celtra Duo showed significantly lower flexural strength than IPS e.max CAD. However, it displayed higher flexural strength than IPS Empress CAD, although the difference was only significant for glazing and the combination of polishing and glazing.
This study provides the clinician with an estimate of the flexural strength of glass-ceramic materials and shows how various surface treatments affect their strength.
评估和比较三种 CAD-CAM 玻璃陶瓷材料的弯曲强度，并研究不同表面处理对其弯曲强度的影响。
从三种不同类型的 CAD-CAM 陶瓷块中制备 120 个矩形试件，并将其分为三组：氧化锆增强锂硅玻璃陶瓷（Celtra Duo，第 1 组）、透锂长石增强玻璃陶瓷（IPS Empress CAD，第 2 组）和二硅酸锂陶瓷（IPS e.max CAD，第 3 组）。试件的尺寸标准化为 14.5x12.5mm 和 1.5mm 厚度。每组试件随机分为四个亚组。第 1 亚组（NS）未进行任何表面处理；第 2 亚组（P）仅进行抛光处理；第 3 亚组（G）仅进行上釉处理；第 4 亚组（PG）同时进行抛光和上釉处理。进行双轴弯曲强度（FS）测试直至试件断裂；以 MPa 为单位计算 FS。所有分析均使用 SPSS 版本 24 进行。
第 NS2 组的 FS 最低（89.34±25.30MPa）。第 PG3 组的 FS（365.38±52.52MPa）明显高于第 P3 组（268.15±48.34MPa）。对于每种表面处理，材料组之间均存在统计学显著差异：IPS e.max CAD 的 FS 最高，明显大于 Celtra Duo 和 IPS Empress CAD。对于三种测试材料，抛光和上釉表面处理的组合导致的弯曲强度明显高于单独抛光处理。对于每种材料，以下表面处理之间没有发现显著差异：对照和仅抛光表面处理；单独上釉和抛光和上釉表面处理的组合。对于每种表面处理，Celtra Duo 的弯曲强度明显低于 IPS e.max CAD。然而，它的弯曲强度高于 IPS Empress CAD，尽管仅在上釉和抛光和上釉的组合处理时差异显著。
本研究为临床医生提供了玻璃陶瓷材料弯曲强度的估计值，并展示了不同表面处理如何影响其强度。
