論文の公開元へInfluence of location of osseointegrated implant on stress distribution in implant supported longitudinal removable partial dentures: 3-dimensional finite element analysis
概要
Purpose: The purposes of the study were to evaluate the biomechanical behavior of a mandibular distal extension removable partial denture associated with an implant, including its different distribution on stress within bone, alveolar mucosa, and implant, as well as on the displacement of alveolar mucosa and RPD.by 3-dimensional Finite Element method.
Materials and methods: The 3-dimensional finite element analysis method was selected to evaluate the stress values, distribution and displacement in six geometric 3-D models which were prepared by FEM software package and CT scan of patient mandible, composed of: mandibular, alveolar mucosa, nature tooth and distal extension RPD with implant support. All implants have the same specifications 4.1 *10 mm. Six mandible models were simulated: model A containing tooth 31-33,41,42 and the distal alveolar edge; model B–similar to model A, but with a conventional removable partial denture to replace the absent teeth; model C–F to simulate the situation of different distribution positions; 50 N vertical forces were utilized as load cases. Stress distribution and Von Mises stress values were assessed for simulated tissues and implants. Also 3-dimensional displacement of alveolar mucosa and RPD were evaluated using FEM software.
Results: 1. With or without implant support, stress concentrations occur in the buccal side of the alveolar ridge in the premolar area.2. Using implant to support RPD can reduce the Von Mises stress on the cortical bone and alveolar mucosa. At the same time, the deformation of the denture and alveolar mucosa is reduced, and the Von Mises stress of the cancellous bone is increased under load.3. Under the functional load, the denture is prone to uneven deformation, and it appears in the mistal retainer. With the support of the implant, the denture displacement is reduced and the deformation is uniform.4. As the implant moves in the distance, the support for the premolar area has gradually eased and support for the molar area has increased. The implant bears most of the load under functional loading.
Conclusions: 1. The maximum stress of cortical bone, cancellous bone and mucous under the functional load of traditional longitudinal partial denture is concentrated on the buccal side of the premolar area.2. The support of the implant reduces the burden on the abutment while making the occlusal force distribution more uniform.3. The maximum stress of the implant is concentrated in the neck and 1/3 of the root.4. In the premolar area, the implant effectively disperses the force and reduces the stress value of the cortical bone; In the molar area, the cortical bone takes more occlusal force and the implant is protected.
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