Patil Abhijit, Singh Kishan, Sahoo Sukant, Suvarna Suraj, Kumar Prince, Singh Anupam
Department of Prosthodontics, Bharati Vidyapeeth Dental College and Hospital, Pune, India.
Department of Prosthodontics, Shree Bankey Bihari Dental College and Research Centre, Ghaziabad, Uttar Pradesh, India.
Eur J Dent. 2013 Jul;7(3):272-277. doi: 10.4103/1305-7456.115409.
The aims of the study are to assess the marginal accuracy of base metal and titanium alloy casting and to evaluate the effect of repeated ceramic firing on the marginal accuracy of base metal and titanium alloy castings.
Twenty metal copings were fabricated with each casting material. Specimens were divided into 4 groups of 10 each representing base metal alloys castings without (Group A) and with metal shoulder margin (Group B), titanium castings without (Group C) and with metal shoulder margin (Group D). The measurement of fit of the metal copings was carried out before the ceramic firing at four different points and the same was followed after porcelain build-up.
Significant difference was found when Ni-Cr alloy samples were compared with Grade II titanium samples both before and after ceramic firings. The titanium castings with metal shoulder margin showed highest microgap among all the materials tested.
Based on the results that were found and within the limitations of the study design, it can be concluded that there is marginal discrepancy in the copings made from Ni-Cr and Grade II titanium. This marginal discrepancy increased after ceramic firing cycles for both Ni-Cr and Grade II titanium. The comparative statistical analysis for copings with metal-collar showed maximum discrepancy for Group D. The comparative statistical analysis for copings without metal-collar showed maximum discrepancy for Group C.
本研究旨在评估贱金属和钛合金铸造的边缘精度，并评估重复陶瓷烧制对贱金属和钛合金铸件边缘精度的影响。
用每种铸造材料制作20个金属基底冠。标本分为4组，每组10个，分别代表无金属肩台边缘的贱金属合金铸件（A组）、有金属肩台边缘的贱金属合金铸件（B组）、无金属肩台边缘的钛铸件（C组）和有金属肩台边缘的钛铸件（D组）。在陶瓷烧制前，在四个不同点对金属基底冠的适合性进行测量，烤瓷修复后进行同样的测量。
在陶瓷烧制前后，镍铬合金样品与II级钛样品比较均发现有显著差异。在所有测试材料中，有金属肩台边缘的钛铸件显示出最大的微间隙。
基于所发现的结果以及研究设计的局限性，可以得出结论，由镍铬合金和II级钛制成的基底冠存在边缘差异。对于镍铬合金和II级钛，这种边缘差异在陶瓷烧制循环后均增加。对有金属颈圈的基底冠进行的比较统计分析显示，D组差异最大。对无金属颈圈的基底冠进行的比较统计分析显示，C组差异最大。
