ABSTRACT
Objective To redevelop the finite element model libraries and to analyse the stress distribution of telescopic crown dentures. Methods The finite element model libraries were redeveloped based on the model libraries of normal dentition, fixed partial denture and removable partial denture. With the help of softwares such as DELL Precision Graphics Workstation, UG 5.0, HyperMesh 7.0 and Abaqus 6.5, the telescopic denture models on the bilateral free-ended case were imported and edited, then the finite element stress analysis was performed. Results The models were easily established. The maximum value of stress and its distribution on abutment root, periodontal membrane, alveolar mucosa, alveolar bone and dental prostheses were observed and studied by the finite element stress analysis. Conclusion The way to establish models of telescopic crown dentures by model libraries is feasible and reliable.
ABSTRACT
Objective To investigate the stress distribution in the abutment and supporting tissues of distal-extension removable partial dentures with mesial and distal occlusal rest under loading. Methods A modular denture model was used to build a model of mandibular dentition defect ( 765┬567 loss) with HyperMesh 7.0 software. Prosthetics with mesial (M model) and distal occlusal rest (D model) were designed with UG 5.0 software, and the finite element models were completed with HyperMesh 7.0 software. The stress distribution was analyzed in the abutment and supporting tissues of distal-extension removable partial dentures with mesial and distal occlusal rest when bilateral vertical forces were applied. Results Compared with M model, D model provided much larger maximum stress in abutments and periodontal membrane. Stress of D model mainly concentrated on roots of 4┬4 , while that of M model uniformly distributed on roots of 43┬34 . The maximum stress of M model was significantly larger than that of D model on the mucosa of edentulous region. The maximum stress on alveolar bone of two models' edentulous region was equal, while the stress of M model distributed more widely. Conclusion It is prior to select mesial occlusal rest in distal-extension removable partial dentures.
ABSTRACT
Objective To establish three dimensional finite element model libraries of telescopic dentures and removable partial dentures by means of model libraries, and compare the characteristics of stress distribution among three prostheses. Methods Normal model libraries were imported and edited, and models of bilateral free-ended cases were established. Based on the model libraries of fixed partial dentures and removable partial dentures, the finite element models of telescopic dentures and removable partial dentures with medial or distal occlusal rest were established using softwares such as DELL Precision Graphics Workstation, UG 5.0, HyperMesh 7.0 and Abaqus 6.5, then finite element stress analysis was performed. Results The stress distribution on abutment root, parodontium, alveolar mucosa and alveolar bone was uniform. The maximum value of stress on the abutment root (6.205 Mpa) was much less than those of two removable partial dentures (18.41 Mpa and 34.49 Mpa). Conclusion For bilateral free-ended cases, the telescopic denture design is uniform in stress distribution with less stress on abutment root, which is healthy to the abutment root and surrounding tissues.
ABSTRACT
Objective To analyse the stress distribution of precision attachment dentures used in distal-extension edentulous cases. Methods The finite element models of conventional removable partial dentures and precision attachment dentures were established by modular denture model, and the models of precision attachment dentures were established with 4┬4 as one abutment or 43┬34 as two abutments. The stress distribution of abutments and supporting tissues was compared by finite element analysis software Abaqus 6.5.Results Under vertical loading or oblique loading, the stress of abutments and supporting tissues from attachment dentures with two abutments was significantly lower than that from attachment dentures with one abutment. The stress of conventional removable partial dentures significantly increased under oblique loading. Conclusion It is reasonable for the design of attachment dentures with two abutments for mandibular distal-extension edentulous cases.
ABSTRACT
Objective To analyse the stress distribution of distal-extension removable partial dentures supported by mini implants. Methods The finite element analysis models of conventional removable partial dentures ( CRPD) and mini implants supported removable partial dentures (ISRPD) were established by modular denture model. The stress distribution of abutments and supporting tissues was compared by finite element analysis software Abaqus 6.5.Results Under vertical loading, the stress of abutment teeth, mucosa of edentulous region and alveolar bone of ISRPD model was lower than that of CRPD model. Under oblique loading, the stress of each part of CRPD model and alveolar bone of ISRPD model significantly increased, while that of abutment teeth and parodontium of ISPRD model decreased. Conclusion The distal-extension removable partial dentures supported by mini implants work well in protecting the abutments and supporting tissues.