Murakami Kazuhiro, Yamamoto Kazuhiko, Sugiura Tsutomu, Kawakami Masayoshi, Horita Satoshi, Kirita Tadaaki
Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara City, Nara, Japan.
Dent Traumatol. 2015 Oct;31(5):396-402. doi: 10.1111/edt.12179. Epub 2015 May 15.
The purpose of this study was to investigate stress on poly-L-lactic acid (PLLA) plates with a thickness of 1.4 mm and titanium plates with a thickness of 1.0 and 1.4 mm placed for mandibular symphyseal fractures with or without conservatively treated, unilateral condylar fractures using finite element analysis. The symphyseal fracture region was defined by the following three conditions: the defect, the callus, and the contact condition. Stress on the plates was analyzed by an applying occlusal force of 478.1 N on the first molar of the non-condylar fracture side. In the model of isolated symphyseal fracture, the maximal stresses were below the material strength in all plate types and conditions. In the models with condylar fracture, the maximal stresses on these plates were much higher than those in the models of isolated symphyseal fracture, especially for the defect condition. Although the maximal stresses on all types of plates in the contact condition were below the material strengths, some of those in the defect condition were higher than these strengths. These results suggest that a PLLA plate can theoretically withstand stress under good reductions of symphyseal fractures, even for condylar fractures; however, both the PLLA plate and titanium miniplate may be at risk of fracture under poor reduction.
本研究的目的是使用有限元分析，调查厚度为1.4毫米的聚左旋乳酸（PLLA）接骨板以及厚度为1.0毫米和1.4毫米的钛接骨板，在用于下颌骨颏部骨折伴或不伴有保守治疗的单侧髁突骨折时所承受的应力。颏部骨折区域由以下三种情况定义：缺损、骨痂和接触情况。通过在非髁突骨折侧的第一磨牙上施加478.1牛的咬合力，分析接骨板上的应力。在孤立的颏部骨折模型中，所有接骨板类型和情况下的最大应力均低于材料强度。在伴有髁突骨折的模型中，这些接骨板上的最大应力远高于孤立的颏部骨折模型中的应力，尤其是在缺损情况下。尽管接触情况下所有类型接骨板的最大应力均低于材料强度，但缺损情况下的一些应力高于这些强度。这些结果表明，理论上PLLA接骨板在颏部骨折良好复位的情况下能够承受应力，即使是髁突骨折；然而，在复位不佳的情况下，PLLA接骨板和微型钛接骨板都可能有骨折风险。
