Department of Stomatological Sciences, School of Dentistry, Federal University of Goiás, Goiânia, GO, Brazil.
J Biomech. 2011 Jun 3;44(9):1735-9. doi: 10.1016/j.jbiomech.2011.03.032. Epub 2011 Apr 15.
An inappropriate prosthetic fit could cause stress over the interface implant/bone. The objective of this study was to compare stresses transmitted to implants from frameworks cast using different materials and to investigate a possible correlation between vertical misfits and these stresses. Fifteen one-piece cast 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 for casting: CP Ti (commercially pure titanium), Co-Cr (cobalt-chromium) or Ni-Cr-Ti (nickel-chromium-titanium) alloys. Each framework was installed over the metal model with all screws tightened to a 10 N cm torque and then, vertical misfits were measured using an optical microscope. The stresses transmitted to implants were measured using quantitative photoelastic analysis in values of maximum shear stress (τ), when each framework was tightened to the photoelastic model to a 10 N cm standardized torque. Stress data were statistically analyzed using one-way ANOVA and Tukey's test and correlation tests were performed using Pearson's rank correlation (α = 0.05). Mean and standard deviation values of vertical misfit are presented for CP Ti (22.40 ± 9.05 μm), Co-Cr (66.41 ± 35.47 μm) and Ni-Cr-Ti (32.20 ± 24.47 μm). Stresses generated by Co-Cr alloy (τ = 7.70 ± 2.16 kPa) were significantly higher than those generated by CP Ti (τ = 5.86 ± 1.55 kPa, p = 0.018) and Ni-Cr-Ti alloy (τ = 5.74 ± 3.05 kPa, p = 0.011), which were similar (p = 0.982). Correlations between vertical misfits and stresses around the implants were not significant as for any evaluated materials.
不合适的义齿会导致接口植入物/骨骼的压力过大。本研究的目的是比较使用不同材料铸造的框架传递给植入物的应力，并研究垂直不匹配与这些应力之间的可能相关性。制作了 15 个模拟固定义齿的一体式铸造框架，这些框架安装在带有 5 个植入物的模型上，根据铸造材料的不同，将它们分为三组：CP Ti（纯钛）、Co-Cr（钴铬）或 Ni-Cr-Ti（镍铬钛）合金。每个框架都在所有螺丝拧紧至 10 Ncm 扭矩的金属模型上安装，然后使用光学显微镜测量垂直不匹配。当每个框架以 10 Ncm 的标准化扭矩拧紧到光弹模型上时，使用定量光弹分析测量传递到植入物的应力，以最大剪应力 (τ) 值表示。使用单向方差分析和 Tukey 检验对应力数据进行统计分析，并使用 Pearson 秩相关检验进行相关性检验（α=0.05）。CP Ti（22.40±9.05 μm）、Co-Cr（66.41±35.47 μm）和 Ni-Cr-Ti（32.20±24.47 μm）的垂直不匹配的平均值和标准差值。Co-Cr 合金产生的应力（τ=7.70±2.16 kPa）明显高于 CP Ti（τ=5.86±1.55 kPa，p=0.018）和 Ni-Cr-Ti 合金（τ=5.74±3.05 kPa，p=0.011），这两种合金之间的差异无统计学意义（p=0.982）。对于任何评估的材料，垂直不匹配与植入物周围的应力之间都没有显著相关性。
