论文部分内容阅读
可切削硅酸锂陶瓷具有很好的色泽和较高的抗弯强度,它既可用于单层冠,也可以用作氧化锆基底冠的饰面瓷,再通过烧结或者粘接方式合成全瓷冠。本文研究了单层冠、烧结双层冠和粘接双层冠等3种结构形式的全瓷冠修复体在典型载荷作用下应力分布差异。建立了下颌第一磨牙单层冠、烧结双层冠和粘接双层冠等3种全瓷冠的三维数值模型,分别对其施加垂直集中载荷和八点均布载荷两种典型载荷,通过数值计算分析3种全瓷冠各部分的应力极值和应力分布。结果表明,3种瓷冠在两种载荷作用下的最大应力均小于材料的弯曲强度。烧结双层冠和粘接双层冠应力分布形式大体相同,与单层冠应力分布趋势不同。粘接双层冠与烧结双层冠相比,饰面瓷应力更大。在采用可切削硅酸锂陶瓷单层冠作为磨牙修复体时,在多次咀嚼载荷作用下高应力区可能导致全瓷冠的使用寿命缩短。与烧结双层冠相比,粘接双层冠的饰面瓷可能存在更大崩瓷的风险。本文结论可为可切削硅酸锂陶瓷材料在实际全瓷冠修复临床应用中提供参考意见。
Lithium silicate cutting ceramics with good color and high bending strength, it can be used for single-layer crown can also be used as zirconia-based crown veneer porcelain, and then by sintering or bonding all-ceramic crown. In this paper, the stress distributions of three kinds of all-ceramic crowns with single crown, sintered double crown and double-bonded crown were studied under typical loading. A three-dimensional numerical model of three kinds of all-ceramic crowns including mandibular first molar single layer crown, double-layer sintered crown and double-layer bonded crown was established. Two kinds of typical loads including vertical concentrated load and eight-point uniform load were applied respectively. The stress extremes and stress distributions of three kinds of all-ceramic crowns were numerically analyzed. The results show that the maximum stress of the three kinds of ceramic crowns under both loadings is less than the bending strength of the material. The stress distributions of the sintered double-layer crown and the double-layer bonded double crown are almost the same, which are different from those of the single-layer crown. Bonding double crown Compared with the sintered double crown, porcelain face more stress. When a machinable lithium silicate monolayer crown is used as a molar restoration, the high stress zone under repeated chewing loads may result in a shortened service life of the all-ceramic crown. Compared with sintered double-crown, the veneer porcelain with double-crown can be bonded at risk of greater collapse. The conclusion of this paper can provide reference for cutting ceramic lithium silicate materials in clinical application of all-ceramic crowns.