Biomechanical analysis of the stresses generated by different disocclusion patterns in an implant-supported mandibular complete denture

OBJECTIVES: This study evaluated by three-dimensional finite element analysis the tensions generated by different disocclusion patterns (canine guide and bilateral balanced occlusion) in an implant-supported mandibular complete denture. MATERIAL AND METHODS: A three-dimensional model of implant-supported mandibular complete denture was fabricated according to the Brånemark protocol. A 5-element 3.75 x 13-mm screw-shape dental implant system was modeled for this study. The implants were located in the inter-mental foramen region with 3-mm-high prosthetic components joined by a nickel-chromium framework with 12-mm bilateral cantilever covered by acrylic resin and 12 acrylic denture teeth. SolidWorks® software was used before and after processing the simulations. The mechanical properties of the components were inserted in the model and a 15 N load was established in fixed points, in each one of the simulations. Data were collected in the entire nickel-chromium framework. The results were displayed three-dimensionally as color graphic scales. RESULTS: The canine guide generated greater tensions in the region of the first implant, while the bilateral balanced occlusion generated great tensions in the entire metallic framework. The maximum tension found in the simulation of the bilateral balanced occlusion was 3.22 fold higher than the one found in the simulation of the disocclusion in canine guide. CONCLUSION: The pattern of disocclusion in canine guide is the ideal for implant-supported mandibular complete denture

Analysis of Bone-implant Interfacial Stress during Disocclusion in Complete Implant-supported Prosthesis: A Finite Element Study

Aim: Little is known about the biomechanical behavior of disocclusion patterns in implant-supported prostheses. Thus, the aim of the present study was to analyze the stresses generated at bone-implant interface during different patterns of disocclusion in an implant-supported lower complete denture without free distal ends using the three-dimensional (3-D) finite element method. Study Design: Finite element method. Methods: A 3-D model of a complete denture supported by five inter-foraminal implants and two distal was developed (CAE software Abaqus). A canine guide disocclusion (CG) was simulated applying a nodal load of 15 N at an angle of 45° on the canine tooth prosthesis, while to a bilateral balanced occlusion (BBO) a similar load pattern was applied at four distinct points, bilaterally. Linear elastic static analysis was used to compare the magnitude of maximum and minimum principal stresses at bone-implant interface for each simulation. Results: The disocclusion pattern generated during CG exhibited a greater stress concentration at the bone-implant interface of the distal implant on the working side. BBO showed a more homogeneous stress distribution pattern at the bone-implant interface of the two distal implants. Anterior implants showed lower stress concentration. Conclusions: Bilateral balanced occlusion (BBO) resulted in a more favorable stress distribution in this complete implant-supported prosthesis model

Standard of disocclusion in complete dentures supported by implants without free distal ends: analysis by the finite elements method

OBJECTIVE: The occlusal patterns are key requirements for the clinical success of oral rehabilitation supported by implants. This study compared the stresses generated by the disocclusion in the canine guide occlusion (CGO) and bilateral balanced occlusion (BBO) on the implants and metallic infrastructure of a complete Brånemark protocol-type denture modified with the inclusion of one posterior short implant on each side. MATERIAL AND METHODS: A three-dimensional model simulated a mandible with seven titanium implants as pillars, five of them installed between the mental foramen and the two posterior implants, located at the midpoint of the occlusal surface of the first molar. A load of 15 N with an angle of 45º was applied to a tooth or distributed across three teeth to simulate the CGO or BBO, respectively. The commercial program ABAQUS(®) was used for the model development, before and after the processing of the data. The results were based on a linear static analysis and were used to compare the magnitude of the equivalent stress for each of the simulations. RESULTS: The results showed that the disocclusion in CGO generated higher stresses concentrated on the working side in the region of the short implant. In BBO, the stresses were less intense and more evenly distributed on the prosthesis. The maximum stress found in the simulation of the disocclusion in CGO was two times higher than that found in the simulation of the BBO. The point of maximum stress was located in the neck of the short implant on the working side. CONCLUSIONS: Under the conditions of this study, it was concluded that the BBO pattern was more suitable than CGO for the lower complete denture supported by implants without free distal ends

Análise das tensões geradas por dois padrões de desoclusão em um modelo tridimensional de prótese total implantossuportada sem extensão distal livre

Exportado OPUSMade available in DSpace on 2019-08-14T05:56:25Z (GMT). No. of bitstreams: 1 tese_doutorado_gustavo_diniz_greco.pdf: 1019869 bytes, checksum: 74a52bbf52bde6ee4e536a21da5f7054 (MD5) Previous issue date: 25Este trabalho analisou, pelo método dos elementos finitos tridimensionais (3D), as tensões geradas nos implantes, infra-estrutura metálica e na interface osso/implante, por diferentes padrões de desoclusão em uma prótese total inferior, implantossuportada, sem extremidade distal livre. Foi desenvolvido um modelo 3D de uma prótese total implantossuportada, inferior, propondo uma modificação no protocolo de Brånemark, incluindo dois implantes curtos na região distal da mandíbula. O pacote do programa Abaqus® foi utilizado no pré e pós processamento dos dados. Os resultados obtidos mostram que nos padrões de desoclusão em guia canino (GC) e oclusão balanceada bilateral (OBB) baixos níveis de tensões de tração foram visualizados em toda estrutura óssea de suporte. Na desoclusão em GC, áreas de maior concentração de tração foram detectadas na interface osso/implante da região mesial do implante distal do lado de trabalho e tensões de compressão foram visualizadas no tecido ósseo nas interfaces osso/implante das regiões distais de canino e do implante distal do lado de trabalho. As maiores tensões foram localizadas na região do pescoço do implante curto do lado de trabalho. Na OBB, áreas de concentração de tensões de tração e compressão ocorreram nas interfaces osso/implante dos implantes distais, no sentido vestíbulo-lingual. Não foram visualizadas áreas de tensões de compressão significativas nos implantes anteriores. O padrão de OBB seria mais indicado por proteger os implantes anteriores, além das áreas de concentração de tração e compressão nos implantes distais se inverter conforme se alternam os lados de trabalho e balanceio. A inclusão dos implantes curtos nas regiões distal mandibulares gera uma melhor distribuição das tensões nos implantes pilares.This study analyzed by the finite element method (FEM), the stresses generated in the implants, metallic infrastructure and the bone / implant interface, for different patterns of disocclusion in a mandible complete denture, supported by implants without free distal end. We developed a 3D model of a complete denture supported by implants, proposing a Brånemark protocol modification, including two short implants in the mandible distal region. The program package ABAQUS ® was used in pre and post data processing. The results show that in patterns of disocclusion in canine guide (CG) and bilateral balanced occlusion (BBO) low levels of tensile stresses were seen in all bone structure support. In CG, areas of high concentration were found traction in the interface bone/implant in the mesial region of the distal implant on the work side and compressive stress were seen on bone tissue interfaces in bone/implant of the canine and distal regions of the distal implant on the work side. The highest stresses were located in short implant neck on the work side. In BBO, concentration areas of tensile and compression occurred at the bone/implant interface of distal implant in the buccolingual direction. There were no areas of significant compressive stress in the anterior implants. The BBO pattern is more appropriate for protecting anterior implants. The focus areas of tension and compression in the distal implants to reverse as alternate work and balancing side. The inclusion of short implants in the mandible distal region generates a better stresses distribution in the implants

Standard of disocclusion in complete dentures supported by implants without free distal ends: analysis by the finite elements method

OBJECTIVE: The occlusal patterns are key requirements for the clinical success of oral rehabilitation supported by implants. This study compared the stresses generated by the disocclusion in the canine guide occlusion (CGO) and bilateral balanced occlusion (BBO) on the implants and metallic infrastructure of a complete Brånemark protocol-type denture modified with the inclusion of one posterior short implant on each side. MATERIAL AND METHODS: A three-dimensional model simulated a mandible with seven titanium implants as pillars, five of them installed between the mental foramen and the two posterior implants, located at the midpoint of the occlusal surface of the first molar. A load of 15 N with an angle of 45° was applied to a tooth or distributed across three teeth to simulate the CGO or BBO, respectively. The commercial program ABAQUS® was used for the model development, before and after the processing of the data. The results were based on a linear static analysis and were used to compare the magnitude of the equivalent stress for each of the simulations. RESULTS: The results showed that the disocclusion in CGO generated higher stresses concentrated on the working side in the region of the short implant. In BBO, the stresses were less intense and more evenly distributed on the prosthesis. The maximum stress found in the simulation of the disocclusion in CGO was two times higher than that found in the simulation of the BBO. The point of maximum stress was located in the neck of the short implant on the working side. CONCLUSIONS: Under the conditions of this study, it was concluded that the BBO pattern was more suitable than CGO for the lower complete denture supported by implants without free distal ends

Stress analysis on the free-end distal extension of an implant-supported mandibular complete denture

A comparative and qualitative analysis of the tensions generated in the cantilever region of an implant-supported mandibular complete denture was conducted using the three-dimensional finite element method. The mechanical properties of the components were input in the model and a load of 15 N was applied in pre-determined points. In the first simulation, the load was applied on the occlusal surface of the first premolar. In the second simulation, it was applied on the first and second premolars. In the third simulation, it was applied on the first and second premolars and on the first molar. The different occlusion patterns produced similar tension distributions in the cantilever region, which followed a similar pattern in the three simulations. In all of the cases, the highest levels of tension were located in the region of the first implant. However, as the loads were dislocated distally, the tensions increased considerably. The more extensive the cantilever, the more compromised will be the infrastructure, the prosthetic components and the implants. Regardless of the length of the cantilever, the highest tensions will always be located in the region of the implant next to the load application point