Sorrentino Roberto, Aversa Raffaella, Ferro Valeria, Auriemma Tommaso, Zarone Fernando, Ferrari Marco, Apicella Antonio
Department of Restorative Dentistry and Dental Materials, University of Siena, Siena, Italy.
Dent Mater. 2007 Aug;23(8):983-93. doi: 10.1016/j.dental.2006.08.006. Epub 2006 Oct 30.
The present comparative analysis aimed at evaluating which combination of restorative materials resulted in the most homogeneous stress and strain distributions.
A three-dimensional finite element analysis was performed. All the nodes on the external surface of the root were constrained in all directions. Eighteen experimental models with different material properties and configurations were simulated. An arbitrary load of 10N was applied at 60 degrees angle with tooth longitudinal axis on the palatal surface of the crown. Von Mises (equivalent stresses) energetic criterion was chosen.
In all the models the values of both strain and stress recorded at the middle third of the buccal aspect of the root surface were at their maxima. On the contrary, the minimum values were noticed at level of both the apical portion of the post and the root apex. The maximum stresses were evidenced at level of the cemento-enamel junction (CEJ) on both the buccal and palatal aspects of root cement and dentin. Stress progressively decreased from the outer to the inner part of the root and from the CEJ towards the incisal margin of the crown as well.
The results of the present study would allow clinicians to make an informed choice from among available materials to restore endodontically treated teeth.
本比较分析旨在评估哪种修复材料组合能产生最均匀的应力和应变分布。
进行三维有限元分析。牙根外表面的所有节点在各个方向上均受到约束。模拟了18个具有不同材料特性和结构的实验模型。在牙冠腭面与牙齿纵轴呈60度角处施加10N的任意载荷。选择冯·米塞斯（等效应力）能量准则。
在所有模型中，牙根表面颊侧中三分之一处记录的应变和应力值均为最大值。相反，在桩尖部和根尖水平处观察到最小值。在牙根牙骨质和牙本质的颊侧和腭侧的牙骨质 - 釉质界（CEJ）水平处出现最大应力。应力从牙根外部向内部以及从CEJ向牙冠切缘逐渐降低。
本研究结果将使临床医生能够在现有材料中做出明智选择，以修复经牙髓治疗的牙齿。
