ABSTRACT
INTRODUCTION: The success of bone-implant prostheses depends on several factors, among them an adequate distribution and passive adaptation of occlusal loading. OBJECTIVE: this study evaluated the stress distribution in mandibular implant-supported prosthesis with internal connection morse taper interface, under effect of number of implants (4 or 5) and loadings (bilateral 100 N, bilateral 300 N). MATERIALS AND METHODS: the virtual models were subjected to analysis by 3D finite element method, across four experimental conditions. RESULTS: The stress values were evenly distributed to the peri-implant bone and implants in all simulated conditions. Stress values did not increase in the same proportion as the increase in the applied load (from 100 to 300 N). The stress value was 1.1 times higher on the implants and nearly doubled (1.5-2 times) on the peri-implant bone. CONCLUSION: For mandibular implant-supported prosthesis, the morse taper interface is strongly recommended, with similar mechanical demand for four and five implants in both loading conditions. Five implants offered no additional benefit over four implants. The commercial pure titanium frameworks presented stress values close to the yield strength of the metal, especially at the intersection with the cantilever.
Subject(s)
Dental Implants , Mandible , Biomechanical Phenomena , Dental Prosthesis Design , Dental Stress Analysis , Finite Element Analysis , Prostheses and Implants , Stress, MechanicalABSTRACT
This study evaluated the influence of implant-abutment connections on stress distribution through 3D finite element analysis. Three-dimensional models of an implant-supported fixed prosthesis in the jaw retained by four implants with different connection systems (external hex and Morse taper) were analyzed. External hex connection promoted higher microstrain values, which were concentrated on the cervical region of the distal implants extending into the trabecular bone, while Morse taper connection provided a more even distribution of the microstrain on all implants. Implant-supported fixed prostheses with external hex connections tend to concentrate strain in the distal implants, while Morse taper connection promoted a better situation. On the other hand, there was greater demand on the prosthetic screws and abutments of Morse taper connections than on external hex connections.
Subject(s)
Dental Implant-Abutment Design , Dental Prosthesis, Implant-Supported , Biomechanical Phenomena , Computer Simulation , Denture Retention , Denture, Complete, Lower , Denture, Overlay , Elastic Modulus , Finite Element Analysis , Humans , Imaging, Three-Dimensional/methods , Mandible/physiopathology , Materials Testing , Models, Biological , Stress, Mechanical , Surface PropertiesABSTRACT
This study evaluated the effects of axial and oblique occlusal loading on implant-supported partial dentures with different connection systems (external hexagon, internal hexagon, and Morse taper). Upon axial loading, all systems presented similar stress values. Stress values increased under oblique loading. Stress distribution changed for some of the internal connection structures. It can be concluded that oblique load increases stress on bone structures and prosthetic components. Internal connection system implants present more favorable stress distribution patterns than do external connection system implants.
