Esquivel-Upshaw J F, Chai J, Sansano S, Shonberg D
Department of Prosthodontics, University of Florida College of Dentistry, Gainesville, USA.
Int J Prosthodont. 2001 May-Jun;14(3):284-8.
The increased demand for tooth-colored restorations has prompted the use of ceramics in areas that are subject to masticatory stresses. To maximize the strength of these restorations, manufacturers and clinicians advocate placement of core materials in lieu of veneering materials in areas that are more susceptible to fracture. The objectives of this study were to determine the: resistance to staining of three core porcelains used for all-ceramic restorations, Procera, IPS Empress, and In-Ceram, through the use of colorimetry and visual observation; flexural strength of these porcelains under a three-point bend test; and chemical solubility in a controlled environment.
Lab* values were obtained for each specimen before and after immersion in a saturated solution of methylene blue in ethanol for 24 hours. Visual observation was also performed to ascertain color differences before and after staining. A three-point bend test was used to determine flexural strength. A reflux-condenser type, three-piece extraction apparatus was used with 4% acetic acid solution for 16 hours to determine solubility. Each sample was weighed before and after the reflux procedure to ascertain percentage weight loss.
The mean delta E obtained for IPS Empress was 14.5; In-Ceram was 9.2, and Procera was 9.0. Flexural strength obtained for IPS Empress, In-Ceram, and Procera was 176.9 MPa, 323.4 MPa, and 464.3 MPa, respectively. Weight loss of IPS Empress, In-Ceram, and Procera was 0.056%, 0.734%, and 0.003%, respectively.
IPS Empress showed the least resistance to staining. IPS Empress had the lowest flexural strength, while Procera had the highest. In-Ceram demonstrated the highest chemical solubility.
对牙齿颜色修复体需求的增加促使陶瓷在承受咀嚼应力的区域得到应用。为使这些修复体的强度最大化，制造商和临床医生主张在更易发生断裂的区域使用核心材料而非贴面材料。本研究的目的是通过比色法和视觉观察确定用于全瓷修复体的三种核心瓷（Procera、IPS Empress和In-Ceram）的抗染色性；在三点弯曲试验下这些瓷的抗弯强度；以及在可控环境中的化学溶解性。
在每个样本浸入亚甲蓝乙醇饱和溶液24小时前后获取其Lab*值。还进行了视觉观察以确定染色前后的颜色差异。使用三点弯曲试验来确定抗弯强度。使用回流冷凝器式三件萃取装置，用4%醋酸溶液处理16小时以确定溶解性。在回流过程前后对每个样本称重以确定重量损失百分比。
IPS Empress的平均色差ΔE为14.5；In-Ceram为9.2，Procera为9.0。IPS Empress、In-Ceram和Procera的抗弯强度分别为176.9MPa、323.4MPa和464.3MPa。IPS Empress、In-Ceram和Procera的重量损失分别为0.056%、0.734%和0.003%。
IPS Empress表现出最低的抗染色性。IPS Empress的抗弯强度最低，而Procera最高。In-Ceram表现出最高的化学溶解性。
