de Torres Erica Miranda, Rodrigues Renata Cristina Silveira, de Mattos Maria da Gloria Chiarello, Ribeiro Ricardo Faria
University of São Paulo, Dental School of Ribeirão Preto, Department of Dental Materials and Prosthodontics, Ribeirão Preto, SP, Brazil.
J Dent. 2007 Oct;35(10):800-5. doi: 10.1016/j.jdent.2007.07.013. Epub 2007 Sep 6.
The purpose of this study was to measure and compare the passive fit and vertical fit of one-piece cast frameworks fabricated with three different materials: commercially pure titanium (CP Ti), cobalt-chromium alloy (Co-Cr) and nickel-chromium-titanium alloy (Ni-Cr-Ti).
Fifteen frameworks simulating bars for fixed prosthesis in a model with five implants were fabricated and arranged into three different groups according to the material used. The fit of the framework abutment interface was measured using an optical microscope, when only one screw was manually tightened at a terminal abutment (passive fit) or when all framework screws were tightened to 10 N cm torque (vertical fit). Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (alpha=0.05).
Mean and standard deviation values of passive fit and vertical fit are presented, respectively: CP Ti [88 (74) microm and 22 (9) microm], Co-Cr [229 (184) microm and 66 (35) microm], Ni-Cr-Ti [200 (175) microm and 32 (24) microm]. There were no significant differences between passive fit of Co-Cr and Ni-Cr-Ti frameworks (p=0.313), but both alloys were statistically different from CP Ti (p<0.001 and 0.035, respectively), which showed the best results. As for vertical fit, CP Ti and Ni-Cr-Ti alloy were statistically similar (p=0.162) and they presented a better vertical fit than Co-Cr alloy (p<0.001).
Within the limitations of this study, it was possible to conclude that one-piece cast frameworks resulted in unacceptable passive fit and vertical fit, no matter which material had been used to fabricate them. However, the best results were obtained using CP Ti followed by Ni-Cr-Ti and Co-Cr alloys, respectively.
本研究旨在测量并比较采用三种不同材料制成的一体式铸造支架的被动适合性和垂直适合性，这三种材料分别为商业纯钛（CP Ti）、钴铬合金（Co-Cr）和镍铬钛合金（Ni-Cr-Ti）。
制作了15个模拟固定义齿杆的支架，用于一个有5颗种植体的模型，并根据所用材料分为三个不同的组。当仅在一个末端基牙上手动拧紧一颗螺钉时（被动适合性）或当所有支架螺钉都拧紧至10 N cm扭矩时（垂直适合性），使用光学显微镜测量支架基牙界面的适合性。数据采用Kruskal-Wallis和Mann-Whitney检验进行统计学分析（α = 0.05）。
分别列出了被动适合性和垂直适合性的均值和标准差：CP Ti [88（74）微米和22（9）微米]，Co-Cr [229（184）微米和66（35）微米]，Ni-Cr-Ti [200（175）微米和32（24）微米]。Co-Cr和Ni-Cr-Ti支架的被动适合性之间无显著差异（p = 0.313），但这两种合金与CP Ti在统计学上均有差异（分别为p < 0.001和0.035），CP Ti显示出最佳结果。至于垂直适合性，CP Ti和Ni-Cr-Ti合金在统计学上相似（p = 0.162），并且它们的垂直适合性比Co-Cr合金更好（p < 0.001）。
在本研究的局限性范围内，可以得出结论，无论使用哪种材料制作一体式铸造支架，其被动适合性和垂直适合性都无法接受。然而，使用CP Ti获得的结果最佳，其次分别是Ni-Cr-Ti和Co-Cr合金。
