3D Finite element analysis of bilateral distal-extension extracoronal attachment denture with different abutment periodontal quantity

Objective: To investigate the stress distribution in the bilateral distal-extension attachment denture supporting tissue with different abutment periodontal quantity. Methods: Reconstructed the three-dimensional finite element models of the extracoronal attachment denture with mandibular Kennedy Ⅰ dentition defect, analyzed the stress distribution of the denture supporting tissue with Von Mises ability of sustain pressure when vertical forces were applied, compared the absorbed-periodontal abutment models with the normal-periodontal abutment models. Results: Compared to the normal-periodontal abutment models, when the second premolar periodontal tissues absorbed 1/3, the maximal pressure increased more than twice on the periodontal member and the alveolar bone of the distal-abutment; when the first and the second premolar periodontal tissues absorbed 1/3, the maximal pressure increased about 4-5 times on the periodontal member and the alveolar bone of the distal-abutment. When the number of the absorbed-periodontal abutment was increased, the maximal pressure of the alveolar bone under the denture increased 47%. When the abutment number was increased from two to three, the pressure of supporting tissues obliviously decreased. Conclusion: Restoring mandibular bilateral distal-extension edentulous dentition with extra-coronal attachment, it was necessary to increase the number of the abutment, if only one premolar periodontal tissues was absorbed 1/3; it was not advisable to restore with attachment dentures, if both premolar periodontal support tissues was absorbed.