Sadr Katayoun, Alipour Jahangir, Heidary Fateme
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
J Dent Res Dent Clin Dent Prospects. 2012 Spring;6(2):37-41. doi: 10.5681/joddd.2012.009. Epub 2012 Jun 6.
There are many edentulous people with severely resorbed residual ridges and non-resilient lin-ing mucosa that are unable to tolerate occlusal forces during functional and parafunctional movements. Lining the tissue surface of dentures with a flexible material can theoretically distribute and absorb forces with cushioning effect. The aim of this study was to evaluate the effect of a soft liner on stress levels in mandibular complete denture and its supporting struc-tures by finite element analysis.
A simplified 3-dimensional finite element model of relatively resorbed mandible, mucosa, denture and a soft liner was prepared. Then the model, with and without soft liner, underwent normal vertical and lateral occlusal forces. The stresses were analyzed using the ANSYS 12 software.
Using the soft liner increased stress levels up to 18.5% and 30% in the cortical bone and mucosa, respectively, after vertical load was applied in the incisor region. Application of bilateral vertical load on the molar area increased stress in cortical bone u to 44% and in the mucosa up to 29%. Unilateral loading in the canine area increased stress level in the mucosa up to 63.5%. The highest stress was seen at denture base followed by the cortical bone.
Use of soft liners increased stress in denture supporting structures. Higher level of stress concentration was observed primarily in the denture base followed by the cortical bone.
有许多无牙颌患者，其残余牙槽嵴严重吸收，衬里黏膜缺乏弹性，在功能运动和副功能运动期间无法耐受咬合力量。理论上，用柔性材料衬里义齿组织面可通过缓冲作用分散和吸收力量。本研究的目的是通过有限元分析评估软衬里对下颌全口义齿及其支持结构应力水平的影响。
制备了一个相对吸收的下颌骨、黏膜、义齿和软衬里的简化三维有限元模型。然后，该模型在有和没有软衬里的情况下，承受正常的垂直和侧向咬合力量。使用ANSYS 12软件分析应力。
在切牙区施加垂直载荷后，使用软衬里分别使皮质骨和黏膜中的应力水平增加了18.5%和30%。在磨牙区施加双侧垂直载荷使皮质骨中的应力增加了44%，黏膜中的应力增加了29%。在尖牙区单侧加载使黏膜中的应力水平增加了63.5%。最高应力出现在义齿基托，其次是皮质骨。
使用软衬里会增加义齿支持结构中的应力。主要在义齿基托中观察到较高水平的应力集中，其次是皮质骨。
