Lund P S, Goodkind R J, Swanson S
Department of Prosthodontics, University of Iowa, College of Dentistry, Iowa City.
J Prosthet Dent. 1989 Sep;62(3):278-83. doi: 10.1016/0022-3913(89)90332-6.
Residual stress caused by a mismatch of alloy-porcelain thermal contraction can contribute to clinical failure of a ceramometal restoration. This investigation assessed thermal compatibility of three ceramometal alloys and two opaque porcelains. Thermal expansions of the alloys and porcelains were measured by using a straight push-rod dilatometer. Porcelain glass transition temperatures and expansion values were derived from length-versus-temperature curves. Residual stress states in alloy-porcelain pairs were assessed by comparing expansion values of the components at the porcelain glass transition temperatures. Above that temperature the porcelain viscosity is low and stress relief is possible, whereas below the glass transition the porcelain acts as a stress-supporting solid. Expansion values were in general agreement and glass transition temperatures were slightly lower than values previously reported for similar materials. Alloy-porcelain thermal compatibility for the materials tested appeared more dependent on the opaque porcelain than the alloy.
合金与瓷热收缩不匹配所导致的残余应力会促使金属烤瓷修复体出现临床失败。本研究评估了三种金属烤瓷合金与两种不透明瓷的热相容性。采用直推杆膨胀仪测量合金与瓷的热膨胀情况。瓷的玻璃化转变温度和膨胀值由长度-温度曲线得出。通过比较各组分在瓷玻璃化转变温度时的膨胀值，评估合金-瓷配对组合中的残余应力状态。高于该温度时，瓷的黏度较低，应力得以释放；而低于玻璃化转变温度时，瓷则起到支撑应力的固体作用。膨胀值总体上相符，且玻璃化转变温度略低于先前报道的类似材料的值。对于所测试的材料而言，合金-瓷的热相容性似乎更多地取决于不透明瓷而非合金。
