| Objective:Two-implant-retained mandibular overdentures with magnetic attachments can provide an effective treatment modality for edentulous patients. In this study, a three-dimensional finite element analysis was used to compare the biomechanical characteristics of three different types of magnetic attachments in two-implant-retained mandibular overdenture and to provide a theoretical basis for the design optimization of two-implant-retained mandibular magnetic overdentures and clinical treatment.Methods:Three models of a human mandible were constructed. Magnetic attachments with flat-type, dome-type, and cushion-type were designed to support the overdenture. Four types of load were applied to the overdenture in each model: 100 N vertical and inclined loads on the right first molar and a 100 N vertical load on the right canine and the lower incisors. The biomechanical behaviors of peri-implant bone, abutment, and mucosa were recorded.Results:Under vertical and inclined load conditions, flat-type model exhibited higher levels of maximum equivalent strain/stress in the peri-implant bone and abutment than dome-type and cushion-type model. With molar loading, the strain/stress under inclined loading showed three times higher values than those under vertical loading in all three models. The highest total deformation of the mucosa was observed under inclined molar loading, which was approximately three times as high as under other loading conditions.Conclusions:Dome-type and cushion-type attachment exhibit better strain/stress pattern than flat-type attachment, and oblique load may play a detrimental role for all magnetic attachments in strain/stress distribution and denture stability. These results suggested that dome-type and cushion-type attachment are superior choices in two-implant-retained mandibular overdenture, especially for patients with osteoporosis or bony deficiency in mandible. |
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