Tonella Bianca Piccolotto, Pellizzer Eduardo Piza, Ferraço Renato, Falcón-Antenucci Rosse Mary, Carvalho Paulo S Perri de, Goiato Marcelo Coelho
Department of Dental Materials and Prosthodontics, Araçatuba School of Dentistry - São Paulo State University - UNESP, São Paulo, Brazil.
J Oral Implantol. 2011 Aug;37(4):401-10. doi: 10.1563/AAID-JOI-D-10-00044.
The aim of this study was to evaluate the stress distribution of different retention systems (screwed or cemented) associated with different prosthetic connections (external hexagon, internal hexagon, and Morse taper) in 3-unit implant-supported fixed partial dentures through photoelasticity. Six models were fabricated with photoelastic resin PL-2, and each model contained two implants of 4.0 × 10.0 mm. The models presented different retention systems (screwed and cemented) and different connections (external hexagon, internal hexagon, and Morse taper). The prostheses were standardized and fabricated in Ni-Cr alloy. A circular polariscope was used and axial and oblique (45°) loads of 100 N were applied in a universal testing machine. The results were photographed and analyzed qualitatively with a graphic software (Adobe Photoshop). The screwed retention system exhibited higher number of fringes for both axial and oblique loadings. The internal hexagon implant presented better and lower stress distribution for both cemented and screwed prostheses. The oblique loading increased the number of fringes in all models tested. The cemented retention system presented better stress distribution. The internal hexagon implant was more favorable according to the biomechanical standpoint. The oblique load increased stress in all systems and connections tested.
本研究旨在通过光弹性法评估3单位种植体支持的固定局部义齿中，不同固位系统（螺丝固位或粘结固位）与不同修复体连接方式（外六角、内六角和莫氏锥度）相关的应力分布情况。用光弹性树脂PL-2制作了六个模型，每个模型包含两个4.0×10.0 mm的种植体。这些模型呈现出不同的固位系统（螺丝固位和粘结固位）以及不同的连接方式（外六角、内六角和莫氏锥度）。修复体采用镍铬合金标准化制作。使用圆偏振光镜，并在万能试验机上施加100 N的轴向和斜向（45°）载荷。对结果进行拍照，并使用图形软件（Adobe Photoshop）进行定性分析。对于轴向和斜向加载，螺丝固位系统均显示出更多的条纹。对于粘结和螺丝固位修复体，内六角种植体均呈现出更好且更低的应力分布。斜向加载增加了所有测试模型中的条纹数量。粘结固位系统呈现出更好的应力分布。从生物力学角度来看，内六角种植体更为有利。斜向载荷增加了所有测试系统和连接方式中的应力。
