NumBioLab, Department of Orthodontics, Ludwig-Maximilians University of Munich, Munich, Germany.
Department of Oral and Maxillofacial Surgery, Johannes Kepler University Linz, Linz, Austria.
Dent Traumatol. 2020 Dec;36(6):607-617. doi: 10.1111/edt.12575. Epub 2020 Jul 20.
BACKGROUND/AIM: An increasing number of elderly patients with implant-prosthodontic rehabilitation of the edentulous mandible frequently show increased life activity, and consequently, a greater number of aged patients is at risk for maxillofacial trauma. The aim of this 3-dimensional (3D) finite element analysis (FEA) was to evaluate the biomechanical effects of the edentulous mandible (EM) with and without four splinted interforaminal implants exposed to three different trauma applications including assessment of different mandibular fracture risk areas.
In a 3D-FEA study design, EM with and without four splinted interforaminal implants were exposed to the application of 1000 N at the symphyseal, parasymphyseal, and mandibular angle region. On four pre-defined superficial cortical mandibular areas (symphysis region, mental foramen region, angle of mandible, and mandibular neck) representing regions of interest (ROI), the von Mises stresses were measured for the three trauma applications. For all ROIs, stress values were evaluated and compared for the different force application sites as well as between EM models with and without interforaminal implants.
For EM with and without four splinted interformaninal implants, all traumatic loads generated the highest stress levels at the mandibular neck region. However, in the EM with four splinted interforaminal implants, an anterior symphyseal force application generated significantly (P < .01) increased stress values in the parasymphyseal (mental foramen) region than in EM without implants. For force applications at the parasymphaseal region (mental foramen) and at the angle of the mandible elevated, von Mises stress values were noted directly at the application sites without difference between edentulous mandibles with and without four interforaminal implants.
In an edentulous mandible model with four splinted interforaminal implants, the condylar neck and the mental foramen represent the predilectional risk areas for mandibular fracture for both anterior symphyseal and lateral parasymphyseal force application.
背景/目的：越来越多接受种植义齿修复的无牙颌下颌骨的老年患者生活活动增加，因此，更多的老年患者面临颌面部创伤的风险。本三维（3D）有限元分析（FEA）的目的是评估无牙颌（EM）有无四个夹板间孔植入物的生物力学效应，并分别暴露于三种不同的创伤应用中，包括评估不同下颌骨折风险区域。
在 3D-FEA 研究设计中，将 EM 有无四个夹板间孔植入物暴露于在下颌联合、下颌正中、下颌角区域施加 1000 N 的应用中。在四个预先定义的下颌骨浅层皮质区域（下颌联合区域、颏孔区域、下颌角区域和下颌颈区域）代表感兴趣区域（ROI），测量了三种创伤应用的 von Mises 应力。对于所有 ROI，评估并比较了不同力应用部位以及有无间孔植入物的 EM 模型之间的应力值。
对于有无四个夹板间孔植入物的 EM，所有创伤负荷在下颌颈区域产生最高的应力水平。然而，在具有四个夹板间孔植入物的 EM 中，前联合处的力应用在下颌正中（颏孔）区域产生的应力值明显（P <.01）高于无植入物的 EM。对于在下颌正中（颏孔）区域和下颌角区域施加的力，von Mises 应力值直接在应用部位记录，有无四个间孔植入物的无牙颌之间没有差异。
在具有四个夹板间孔植入物的无牙颌模型中，髁突颈和颏孔是前联合和侧下颌正中受力时下颌骨折的首选风险区域。
