Ku Chul-Whoi, Park Sang-Won, Yang Hong-So
Department of Prosthodontics, College of Dentistry, Chonnam National University, Kwangju, Korea.
J Prosthet Dent. 2002 Aug;88(2):170-5. doi: 10.1067/mpr.2002.127712.
The fracture strength of a number of new ceromer systems for the fabrication of anterior fixed partial dentures is unknown.
The purpose of this study was to compare the fracture strengths of metal-ceramic crowns and 3 types of ceromer crowns in a simulated anterior tooth preparation.
A resin maxillary central incisor analog was prepared with a 5-degree convergence angle and a 90-degree, 1-mm shoulder. The incisal edge was reduced by 2 mm, and the axiogingival and axioincisal line angles were rounded. A mold of this tooth was made with vinyl polysiloxane impression material. Ten wax patterns were made from the mold and cast in a nickel-chromium alloy for the fabrication of metal dies, from which 10 metal-ceramic crowns were fabricated. Ten crowns for each of 3 ceromer systems (Artglass, Sculpture, and Targis) were fabricated from the same metal die. Each crown group was prepared, polymerized, air-particle abraded, and finished in accordance with the specific manufacturer's instructions. All 4 types of finished crowns were luted to the dies and embedded in polymethyl methacrylate resin blocks. Their fracture resistance was tested in a universal testing machine. The load was directed at the incisolingual line angle, at 130 degrees to the long axis of each specimen, until catastrophic failure occurred. A 7-mm-diameter rod was used to load the artificial crowns, with the center of the rod in contact with the crown surfaces. Analysis of variance and Tukey's multiple comparisons test (P<.05) were applied to the data.
Metal-ceramic crowns fractured at significantly higher values than ceromer crowns (1317 vs 602 N, respectively) (P<.05). No significant difference was found among the fracture values of Artglass, Sculpture, and Targis crowns.
Within the limitations of this study, failure load values for the 3 ceromer crowns tested, although significantly lower than the values for metal-ceramic crowns, still exceeded normal occlusal forces.
用于制作前牙固定局部义齿的多种新型陶瓷聚合物系统的断裂强度尚不清楚。
本研究的目的是比较金属烤瓷冠和3种陶瓷聚合物冠在模拟前牙预备中的断裂强度。
用树脂制作上颌中切牙模型，聚合角为5度，肩台为90度、1毫米。切缘降低2毫米，轴龈和轴切线角倒圆。用乙烯基聚硅氧烷印模材料制作该牙齿的模型。从模型制作10个蜡型，用镍铬合金铸造金属代型，由此制作10个金属烤瓷冠。从同一金属代型制作3种陶瓷聚合物系统（Artglass、Sculpture和Targis）的每种10个冠。每个冠组按照特定制造商的说明进行预备、聚合、空气颗粒喷砂处理和精加工。所有4种类型的成品冠粘结到代型上，嵌入聚甲基丙烯酸甲酯树脂块中。在万能试验机上测试它们的抗断裂性。载荷指向切舌线角，与每个试件的长轴成130度，直至发生灾难性破坏。使用直径7毫米的杆加载人工冠，杆的中心与冠表面接触。对数据应用方差分析和Tukey多重比较检验（P<0.05）。
金属烤瓷冠的断裂值显著高于陶瓷聚合物冠（分别为1317 N和602 N）（P<0.05）。Artglass、Sculpture和Targis冠的断裂值之间未发现显著差异。
在本研究的局限性内，所测试的3种陶瓷聚合物冠的破坏载荷值虽然显著低于金属烤瓷冠的值，但仍超过正常咬合力。
