Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo, Egypt.
J Prosthodont. 2011 Dec;20(8):621-7. doi: 10.1111/j.1532-849X.2011.00767.x.
This article reviews a press-on metal (POM) ceramic versus a conventional veneering system regarding marginal gaps, fracture resistance, microhardness, and surface roughness. This was done to provide clinical recommendations for its use.
Forty crowns were constructed and divided into two main groups according to the metal coping design. Group 1: Twenty metal copings with metal margin extending to the axiogingival line angle. Group 2: Twenty metal copings with metal margin 1 mm occlusal to the axiogingival line angle. The specimens of each group were further subdivided into two subgroups (A and B) according to the veneering porcelain used. The vertical marginal gaps of the crowns were measured after veneering placement. For fracture resistance testing, the crowns were subjected to compressive load to failure. Representative samples of the two main groups were selected to measure surface roughness and microhardness.
No statistically significant difference was evident regarding the vertical marginal gap distance in relation to the margin design of both tested groups (p= 0.249, p= 0.815); however, the POM veneer group with metal porcelain margin showed statistically lower marginal gaps than the conventional ceramic veneer group (p= 0.043). Fracture resistance values did not show statistically significant difference regarding the margin design (p= 0.858, p= 0.659) or type of the ceramic veneer material (p= 0.592, p= 0.165). Both groups showed no significant difference in their mean roughness values (p= 0.235). Conventional ceramics showed statistically significantly higher mean microhardness values than POM did (p= 0.008).
This study showed superior marginal adaptation, decreased microhardness, and similar load to failure and roughness values of the POM ceramic system. Moreover, considerable ease and speed of fabrication of this system were evident. The high variation in range values of some tested groups is among the limitations of this study, along with the lack of clinical trials to test the system in vivo.
本文综述了一种按扣式金属陶瓷（POM）与传统贴面系统在边缘间隙、抗折强度、显微硬度和表面粗糙度方面的对比。旨在为其临床应用提供建议。
制作 40 个牙冠并根据金属修复体的设计分为两组。组 1：20 个金属修复体，金属边缘延伸至颊舌向龈缘线角。组 2：20 个金属修复体，金属边缘向颊舌向龈缘线角 1mm 处。每组试件进一步根据使用的饰面瓷分为两个亚组（A 和 B）。贴面放置后测量牙冠的垂直边缘间隙。为了进行抗折强度测试，牙冠承受压缩载荷直至破坏。选择两组的代表性样本测量表面粗糙度和显微硬度。
两组试件的边缘设计与边缘间隙距离之间无统计学差异（p=0.249，p=0.815）；但 POM 贴面组的金属烤瓷边缘间隙显著小于传统陶瓷贴面组（p=0.043）。抗折强度值与边缘设计（p=0.858，p=0.659）或陶瓷贴面材料类型（p=0.592，p=0.165）均无统计学差异。两组的平均粗糙度值无显著差异（p=0.235）。传统陶瓷的平均显微硬度值显著高于 POM（p=0.008）。
本研究表明，POM 陶瓷系统具有更优的边缘适应性、更低的显微硬度，以及相似的失效载荷和粗糙度。此外，该系统具有制造简便、速度快的优点。本研究的局限性包括部分测试组的范围值变化较大，以及缺乏体内临床试验来测试该系统。
