Poletto-Neto Victório, Tretto Pedro Henrique Wentz, Zen Bruno Massucato, Bacchi Ataís, Dos Santos Mateus Bertolini Fernandes
School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
School of Dentistry, Meridional Faculty, Passo Fundo, RS, Brazil.
J Oral Implantol. 2019 Oct;45(5):343-350. doi: 10.1563/aaid-joi-D-18-00305. Epub 2019 Aug 20.
Obtaining parallelism during implant placement is often difficult, leading to inclination of implants. The present study evaluated the stress distribution in 3-unit fixed partial dentures supported by 2 implants with different inclinations and prosthetic abutments. Universal castable long abutments (UCLAs) or tapered abutments were used considering 17° of implant angulation in different directions (mesial, distal, buccal, or lingual). To do so, 3-dimensional finite element models were built and exported to specific analysis software. Forces were applied to the functional cusps. Data were obtained with regard to the maximum principal and von Mises stresses (in MPa). No relevant differences were observed in the stress values in the cortical and cancellous bone nor in the prosthesis with UCLA or tapered abutments. However, a relevant stress reduction in the prosthetic screws of the tilted implant was observed when using UCLA abutments. According to the obtained results, it is possible to suggest that both UCLA or tapered abutments can be used for 3-unit fixed partial dentures when 1 of the implants is tilted. UCLA abutment might lead to less biomechanical problems related to screw loosening or fracture.
在种植体植入过程中获得平行性通常很困难，这会导致种植体倾斜。本研究评估了由两颗具有不同倾斜度的种植体和修复基台支持的三单位固定局部义齿中的应力分布。考虑到种植体在不同方向（近中、远中、颊侧或舌侧）有17°的成角，使用了通用可铸造长基台（UCLAs）或锥形基台。为此，构建了三维有限元模型并导出到特定分析软件中。向功能尖施加力。获取了关于最大主应力和冯·米塞斯应力（单位为MPa）的数据。在皮质骨和松质骨以及使用UCLAs或锥形基台的修复体中的应力值未观察到相关差异。然而，在使用UCLAs基台时，观察到倾斜种植体的修复螺钉中的应力有显著降低。根据获得的结果，可以认为当其中一颗种植体倾斜时，UCLAs或锥形基台均可用于三单位固定局部义齿。UCLAs基台可能导致与螺钉松动或断裂相关的生物力学问题更少。
