Aridome Kumiko, Yamazaki Mayumi, Baba Kazuyoshi, Ohyama Takashi
Removable Prosthodontics/Department of Masticatory Function Rehabilitation, Division of Oral Health Sciences/Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo 113-8549, Japan.
J Prosthet Dent. 2005 Mar;93(3):267-73. doi: 10.1016/j.prosdent.2004.12.005.
Although Ti-6Al-7Nb alloy has several excellent mechanical properties, its poor rigidity has limited its clinical use as a material for the fabrication of a removable partial denture (RPD) major connector.
The purpose of this study was to develop and evaluate strengthening designs of Ti-6Al-7Nb RPD major connectors in an effort to increase rigidity.
Four strengthening designs of Ti-6Al-7Nb alloy major connectors were developed using finite element analysis modeling: wide, thick, thick at the middle, and thick at the anterior and posterior borders. The designs had similar rigidity values to a conventional Co-Cr alloy major connector, as measured by the maximum deformation when a simulated load was applied. Next, 30 Kennedy Class II maxillary RPD specimens, using 6 different major connector designs (n = 5), were fabricated. These 6 designs included Ti-6Al-7Nb alloy RPDs with 4 different strengthening designs, a Ti-6Al-7Nb alloy RPD without strengthening designs, and a conventional Co-Cr alloy RPD as a control. The rigidity of the RPDs was evaluated by measuring strains on the major connector and force on the intaglio surface of a denture base under a 30 N loading condition. The data obtained from the 6 different RPD designs were compared using a repeated measures analysis of variance and the Bonferroni correction (alpha=.05).
The strains on the major connectors and the force on the denture bases measured from the Ti-6Al-7Nb RPD without strengthening designs were significantly larger than those of the standard Co-Cr alloy RPD. The strains measured from the 4 strengthening designs were not significantly larger than those of the Co-Cr alloy RPD.
The results suggest that the strengthening designs tested may improve the rigidity of the Ti-6Al-7Nb alloy major connectors and, hence, may promote clinical application for RPDs.
尽管Ti-6Al-7Nb合金具有多种优异的机械性能，但其较差的刚性限制了其作为可摘局部义齿（RPD）大连接体制造材料的临床应用。
本研究的目的是开发并评估Ti-6Al-7Nb RPD大连接体的强化设计，以提高其刚性。
使用有限元分析模型开发了四种Ti-6Al-7Nb合金大连接体的强化设计：宽型、厚型、中间厚型以及前后边缘厚型。通过施加模拟载荷时的最大变形量测量，这些设计的刚性值与传统钴铬合金大连接体相似。接下来，制作了30个Kennedy II类上颌RPD标本，采用6种不同的大连接体设计（n = 5）。这6种设计包括具有4种不同强化设计的Ti-6Al-7Nb合金RPD、无强化设计的Ti-6Al-7Nb合金RPD以及作为对照的传统钴铬合金RPD。在30 N加载条件下，通过测量大连接体上的应变以及义齿基托内表面上的力来评估RPD的刚性。使用重复测量方差分析和Bonferroni校正（α = 0.05）对从6种不同RPD设计获得的数据进行比较。
未进行强化设计的Ti-6Al-7Nb RPD大连接体上测量的应变以及义齿基托上的力显著大于标准钴铬合金RPD。从4种强化设计测量的应变不显著大于钴铬合金RPD的应变。
结果表明，所测试的强化设计可能会提高Ti-6Al-7Nb合金大连接体的刚性，因此可能会促进RPD的临床应用。
