Fenlon M R, Juszczyk A S, Hughes R J, Walter J D, Sherriff M
Eur J Prosthodont Restor Dent. 1993 Mar;1(3):127-30.
Fifty-six cobalt-chromium removable partial denture frameworks made to the same design were found to fit their master casts poorly. Spaces were significantly greater between palatal aspects of abutment teeth and palatal reciprocal arms, and between buccal aspects of occlusal rests and rest seats. Excessive contraction towards the centre of the palate was found. Expansion of the refractory investment may not have compensated adequately for solidification and cooling contraction of the cobalt-chromium alloy. Although dimensional changes in investment and casting are by volume, no evidence of anisotropic expansion of castings in a vertical direction was found.
研究发现，56个按照相同设计制作的钴铬可摘局部义齿支架与它们的主模型贴合不佳。基牙腭侧与腭侧对抗臂之间、牙合支托和支托窝颊侧之间的间隙明显更大。还发现腭部向中心过度收缩。耐火包埋材料的膨胀可能没有充分补偿钴铬合金凝固和冷却收缩。虽然包埋材料和铸件的尺寸变化是按体积计算的，但未发现铸件在垂直方向有各向异性膨胀的证据。
