Graduate student, Graduate Implantology, Department of Implantology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Provincial Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong, PR China.
Graduate student, Graduate Implantology, Department of Periodontology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Provincial Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong, PR China.
J Prosthet Dent. 2022 May;127(5):783.e1-783.e10. doi: 10.1016/j.prosdent.2022.02.018. Epub 2022 Mar 17.
Inclined distal implants with posterior framework cantilevers are an alternative to straight implants for the treatment of edentulous jaws, avoiding grafting procedures and utilizing pre-existing bone. However, little is known about the implant, framework, and peri-implant bone stresses exerted by this design.
The purpose of this finite element analysis study was to assess the biomechanical properties of the inclined versus straight design, with different implant framework material to generate implant-supported complete-arch fixed mandibular prostheses.
A finite element model of the edentulous mandible was generated by using 4 implants in 2 distinct configurations: the inclined design and the straight design. Different framework materials were tested: pure titanium, cobalt-chromium alloy, type IV gold alloy, zirconia, polyetheretherketone (PEEK), and carbon fiber-reinforced polyetheretherketone (CFR-PEEK). A 300-N load at a 75-degree angle was applied to the occlusal plane from the lingual side of the buccal cusps of the 2 premolars and the first molar teeth. Subsequently, stresses on the implant, surrounding bone, and framework were measured and analyzed quantitatively and qualitatively.
In terms of implant configurations, the inclined design demonstrated less stress on the posterior cortical bone, implants, and framework than the straight design. Comparing the framework materials, zirconia and metal exhibited reduced cortical bone and implants stresses but elevated framework stress when compared with the polymeric frameworks.
From a biomechanical viewpoint, in edentulous patients with excessive posterior alveolar bone resorption, the inclined design exhibited more favorable stress distribution around the posterior implants than the straight design. In implant-supported complete-arch fixed mandibular prostheses, zirconia and metal, particularly cobalt-chromium alloy, distributed the stresses more effectively to the implants and supporting bone than polymeric materials.
带有后框架悬臂的倾斜远端植入物是治疗无牙颌的直体植入物的替代方案，避免了移植手术并利用了现有的骨量。然而，对于这种设计施加在植入物、框架和周围骨上的植入物、框架和周围骨的应力量知甚少。
本有限元分析研究的目的是评估倾斜设计与直体设计的生物力学特性，以及不同的植入物框架材料对产生种植体支持的全颌固定下颌义齿的影响。
通过使用 4 个植入物在 2 种不同的配置中生成无牙颌下颌的有限元模型：倾斜设计和直体设计。测试了不同的框架材料：纯钛、钴铬合金、IV 型金合金、氧化锆、聚醚醚酮（PEEK）和碳纤维增强聚醚醚酮（CFR-PEEK）。从颊尖的舌侧以 75 度角向磨牙的颊侧和近中侧的咬合面施加 300N 的负载。随后，对植入物、周围骨和框架上的应力进行定量和定性测量和分析。
就植入物配置而言，与直体设计相比，倾斜设计在后皮质骨、植入物和框架上的应力更小。比较框架材料时，氧化锆和金属显示出皮质骨和植入物的应力降低，但与聚合物框架相比，框架的应力升高。
从生物力学的角度来看，对于后牙槽骨吸收过多的无牙颌患者，倾斜设计在后部植入物周围表现出更有利的应力分布，而直体设计则不然。在种植体支持的全颌固定下颌义齿中，氧化锆和金属，特别是钴铬合金，比聚合物材料更有效地将应力分布到植入物和支撑骨上。
