Roshdy Mariam Ahmed, El Kerdawy Maha Wagdy, Abo El Fetouh Adel Hamdy, El Far Mahmoud Mokhtar
Department of Prosthodontics, Faculty of Dentistry, Cairo University, Cairo, Egypt.
Department of Prosthodontics, Faculty of Dentistry, Cairo University, Cairo, Egypt.
Comput Biol Med. 2025 Sep;196(Pt C):110897. doi: 10.1016/j.compbiomed.2025.110897. Epub 2025 Aug 7.
Subperiosteal implants (SPIs) are considered a viable treatment option in patients with highly resorbed ridges if extensive bone grafting or other more invasive procedures are not indicated. Traditionally, SPIs were designed in a single-piece fashion, while two-piece SPIs were introduced recently. However, there are no studies in the current dental literature that compared between the two designs.
This three dimensional finite element analysis (3D FEA) was conducted to compare the differences in the biomechanical behavior of two SPI designs: the single-piece and the two-piece SPI framework design.
The study simulated a clinical situation of 2 interforaminal SPI frameworks; a single-piece titanium SPI framework placed on one side of the mandible versus a two-piece titanium SPI framework placed on the contralateral side. The frameworks were restored with a cement-retained SPI framework-supported prosthesis with a shortened dental arch on a total of 4 upstanding abutments, and opposed by a maxillary removable tissue-supported complete denture. The 3D surface model was produced from a multi-slice computed tomographic scan of a patient with an edentulous mandible. The study involved two simulations with unilateral oblique force of 50 N being applied on the prosthesis at the buccal inclines of the lingual cusp of the mandibular second premolar at an angle of 30°. Simulation 1 represented oblique right-side loading on the working side that harbored the single-piece SPI framework, while simulation 2 represented oblique left-side loading on the working side that harbored the two-piece SPI framework. Outcomes included peri-implant stresses, von Mises stress in frameworks, fixation screws, and overlying prosthesis as well as the total deformation of fixation screws.
Stress values at the peri-implant bone, on fixation screws as well as the total deformation of fixation screws were fairly comparable for both SPI framework designs. However, the von Mises stress values recorded for the framework in simulation 2 (left loaded side corresponding to the two-piece SPI framework side) was more than double the von Mises stress values recorded for the framework in simulation 1 (right loaded side corresponding to the single-piece SPI framework side), 150.09 MPa and 60.74 MPa, respectively.
Within the limitations of the current study, and from a biomechanical perspective, stress values in both designs were comparable except for the frameworks, where the single-piece SPI framework design demonstrated superiority over the two-piece SPI framework design.
对于骨高度吸收的患者，如果不需要进行广泛的骨移植或其他更具侵入性的手术，骨膜下种植体（SPI）被认为是一种可行的治疗选择。传统上，SPI采用一体式设计，而两件式SPI是最近才出现的。然而，目前牙科文献中尚无关于这两种设计比较的研究。
进行此项三维有限元分析（3D FEA）以比较两种SPI设计（一体式和两件式SPI框架设计）在生物力学行为上的差异。
本研究模拟了2个双侧孔间SPI框架的临床情况；在下颌骨一侧放置一体式钛SPI框架，对侧放置两件式钛SPI框架。框架采用水泥固位的SPI框架支持的修复体进行修复，该修复体在总共4个直立基牙上带有缩短的牙弓，并与上颌可摘组织支持的全口义齿相对。三维表面模型由一名无牙下颌患者的多层计算机断层扫描生成。本研究包括两次模拟，在模拟中，50 N的单侧斜向力以30°角施加于下颌第二前磨牙舌尖颊侧斜面的修复体上。模拟1表示在带有一体式SPI框架的工作侧进行右侧斜向加载，而模拟2表示在带有两件式SPI框架的工作侧进行左侧斜向加载。结果包括种植体周围应力、框架、固定螺钉和覆盖修复体中的von Mises应力以及固定螺钉的总变形。
两种SPI框架设计在种植体周围骨、固定螺钉处的应力值以及固定螺钉的总变形相当。然而，模拟2（左加载侧对应两件式SPI框架侧）中框架记录的von Mises应力值是模拟1（右加载侧对应一体式SPI框架侧）中框架记录的von Mises应力值的两倍多，分别为150.09 MPa和60.74 MPa。
在本研究的局限性内，从生物力学角度来看，除框架外，两种设计的应力值相当，其中一体式SPI框架设计比两件式SPI框架设计表现更优。
