Finite Element Analysis of Stress Distributions for Mandibular Dental Implant-Supported Overdentures with Magnetic Attachments in Osteoporotic and Normal Bone.

PURPOSE: To compare the biomechanical responses of a normal mandible to an osteoporotic mandible with two-implant-supported magnetic attachments.

MATERIALS AND METHODS: A 3D finite-element model of a two-implant-supported mandibular overdenture with magnetic attachments was developed, and normal and osteoporotic bone samples were prepared. Four types of load were applied to the overdenture in each model: 100 N vertical and oblique loads on the right first molar, and a 100 N vertical load on the right canine and incisors. Biomechanical behaviors of the peri-implant bone, implant, and mucosa were recorded. Maximum equivalent stresses and elastic strains were analyzed.

RESULTS: Equivalent elastic strain in osteoporotic cortical and cancellous bone was 9% to 71% and was 142% and 207% greater than in normal cortical bone, respectively. Equivalent elastic strain in the first molar oblique loading condition was 101% to 190% greater than in the first molar vertical loading condition.

CONCLUSIONS: Osteoporotic cancellous bone was weaker and less resistant to deformation than normal bone, and oblique loading was more harmful than vertical loading.