P Shilpa, R Narendra, Reddy Sesha, Reddy Sashideepth
Prosthodontics, Government Dental College and Hospital, Kadapa, IND.
Cureus. 2019 Nov 26;11(11):e6242. doi: 10.7759/cureus.6242.
Introduction In metal-ceramic restoration, most of the bond failures between the ceramic layer and the metal coping is the chipping of the ceramic layer, thus exposing the metal surface, which compromises the aesthetics. Hence, this leads to the introduction of zirconia-based restorations in dentistry. However, even zirconium coping has the common complication of delamination or porcelain chipping from the zirconium core. Hence, the shear bond strength between the commonly used core materials and ceramic requires investigation to facilitate the materials in clinical use for longevity. Therefore, this study was conducted to compare the shear bond strength between different core materials and ceramic layering to find out the best core material for ceramic bonding. Materials and methods A total number of 45 samples were made as per ISO standardization (base 5 mm diameter and 1 mm thickness, step with 4 mm diameter and 4 mm in length). These samples were divided into three groups, Group A: Nickel-chromium, Group B: Cobalt-chromium, and Group C: Zirconium. Ceramic layering was layered on the top surface of each sample until an ideal height of 4 mm was obtained, and it was subjected to shear bond strength using a universal testing machine with a 50-KN load cell. This was followed by analyzing the nature of the fracture pattern using scanning electron microscopy (SEM). Results There were no significant differences found for the shear bond strength among group A and group B. The zirconium (group C), however, had significantly lower values than both group A and group B. The microscopic examination also revealed that the failure between the coping and the ceramic layer primarily occurred near the interface with the residual veneering porcelain remaining on the core. Conclusions It was found that the shear bond strength of the metal-ceramic group is better than the zirconium ceramic group, however, the fracture between the copings and the ceramic layering is found to be similar for both adhesive and cohesive failure.
引言 在金属烤瓷修复体中，陶瓷层与金属基底之间的粘结失败大多是陶瓷层的崩瓷，从而暴露出金属表面，这会影响美观。因此，这促使牙科领域引入了氧化锆基修复体。然而，即使是氧化锆基底也存在分层或瓷层从氧化锆核上崩落的常见并发症。因此，需要研究常用核材料与陶瓷之间的剪切粘结强度，以便在临床使用中选择寿命更长的材料。因此，本研究旨在比较不同核材料与陶瓷层之间的剪切粘结强度，以找出最适合陶瓷粘结的核材料。
材料与方法 按照ISO标准制作了45个样本（底部直径5mm，厚度1mm，台阶直径4mm，长度4mm）。这些样本分为三组，A组：镍铬合金；B组：钴铬合金；C组：氧化锆。在每个样本的顶面上逐层堆塑陶瓷，直到达到4mm的理想高度，然后使用配备50kN测力传感器的万能试验机对其进行剪切粘结强度测试。随后使用扫描电子显微镜（SEM）分析断裂模式的性质。
结果 A组和B组之间的剪切粘结强度没有显著差异。然而，氧化锆组（C组）的值明显低于A组和B组。显微镜检查还显示，基底与陶瓷层之间的粘结失败主要发生在界面附近，核上残留有 veneering porcelain。
结论 发现金属烤瓷组的剪切粘结强度优于氧化锆陶瓷组，然而，基底与陶瓷层之间的断裂在粘结性和内聚性失败方面相似。
