Solberg K, Heinemann F, Pellikaan P, Keilig L, Stark H, Bourauel C, Hasan I
a Endowed Chair of Oral Technology, Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School , Rheinische Friedrich-Wilhelms University , Bonn , Germany.
b Department of Prosthodontics, Gerodontology and Biomaterials , University of Greifswald , Greifswald , Germany.
Comput Methods Biomech Biomed Engin. 2017 May;20(7):770-782. doi: 10.1080/10255842.2017.1302432. Epub 2017 Mar 10.
The effect of implants' number on overdenture stability and stress distribution in edentulous mandible, implants and overdenture was numerically investigated for implant-supported overdentures. Three models were constructed. Overdentures were connected to implants by means of ball head abutments and rubber ring. In model 1, the overdenture was retained by two conventional implants; in model 2, by four conventional implants; and in model 3, by five mini implants. The overdenture was subjected to a symmetrical load at an angle of 20 degrees to the overdenture at the canine regions and vertically at the first molars. Four different loading conditions with two total forces (120, 300 N) were considered for the numerical analysis. The overdenture displacement was about 2.2 times higher when five mini implants were used rather than four conventional implants. The lowest stress in bone bed was observed with four conventional implants. Stresses in bone were reduced by 61% in model 2 and by 6% in model 3 in comparison to model 1. The highest stress was observed with five mini implants. Stresses in implants were reduced by 76% in model 2 and 89% increased in model 3 compared to model 1. The highest implant displacement was observed with five mini implants. Implant displacements were reduced by 29% in model 2, and increased by 273% in model 3 compared to model 1. Conventional implants proved better stability for overdenture than mini implants. Regardless the type and number of implants, the stress within the bone and implants are below the critical limits.
针对种植体支持的覆盖义齿，对种植体数量对无牙下颌骨、种植体及覆盖义齿的覆盖义齿稳定性和应力分布的影响进行了数值研究。构建了三个模型。覆盖义齿通过球头基台和橡胶圈与种植体相连。在模型1中，覆盖义齿由两颗传统种植体固位；在模型2中，由四颗传统种植体固位；在模型3中，由五颗微型种植体固位。覆盖义齿在尖牙区域与覆盖义齿呈20度角且在第一磨牙处垂直施加对称载荷。数值分析考虑了两种总力（120、300 N）的四种不同加载条件。使用五颗微型种植体时覆盖义齿的位移比使用四颗传统种植体时高约2.2倍。四颗传统种植体时骨床中的应力最低。与模型1相比，模型2中骨内应力降低了61%，模型3中降低了6%。五颗微型种植体时观察到的应力最高。与模型1相比，模型2中种植体内应力降低了76%，模型3中增加了89%。五颗微型种植体时观察到的种植体位移最高。与模型1相比，模型2中种植体位移降低了29%，模型3中增加了273%。传统种植体对覆盖义齿的稳定性证明比微型种植体更好。无论种植体的类型和数量如何，骨和种植体内的应力均低于临界极限。
