Comparative Evaluation of the Stresses Applied to the Bone, fixtures, and Abutments of Implant-Supported Fixed-Partial-Dentures with Different Long-Spans, After Cyclic Loading Using 3 Dimensional Finite-Element-Method Evaluation of implant-supported-FPDs

Objectives: The pattern of forces transmission and the stress distribution are very important in success or failure of implant-supported fixed-partial-dentures (ISFPD). The exact number of pontics between two implant abutments has always been debatable. The reliability of Ante’s law for ISFPDs is also questionable. The aim of this study was to evaluate the stresses applied to the bone and abutments of an ISFPD with two implants using 3D finite element method (3D FEM). Materials and Methods: In this study, a model with type 2 bone and two implants (Diameter: 4.1, Length: 12 mm, solid abutment, solid cover, ITI, Straumann, Switzerland) were simulated by Solidworks 2007 software. Three-unit, 4-unit, and 5-unit ISFPD models were designed in the software. Osseointegration was assumed 100% between implants and bone. For all three models, forces equivalent to 50, 100, and 150 N were respectively applied to the first premolar, the second premolar, and the first molar dynamically. The maximum Vonmisses stresses (VMS) and strain values (SV) were recorded. Results: The maximum VMS was seen in the bones around the crestal area of the cortical part in all three models. The maximum VMS applied in 5-unit model bone were higher than thoseof two other models. The maximum VMS in the abutments and fixtures of 5-unit model were higher than those of 3-unit and 4-unit ISFPDs. Conclusion: The VMS imposed in 5-unit ISFPD in type II bone were comparable with thoseof 3-unit and 4-unit ISFPDs. Of course, all the strains were in the bone endurance range. VMS in the abutments and fixturesof all three models were in the permanent-durability-range of the bone

Functional Biomimetic Dental Restoration

Bioinspired functionally graded approach is an innovative material technology, which has rapidly progressed both in terms of materials processing and computational modeling in recent years. Bioinspired functionally graded structure allows the integration of dissimilar materials without formation of severe internal stress and combines diverse properties into a single material system. It is a remarkable example of nature’s ability to engineer functionally graded dental prostheses. Therefore, this novel technology is designed to improve the performance of the materials in medical and dental fields. Thus, this chapter book reviews the current status of the functionally graded dental prostheses and biomimetic process inspired by the human bone, enamel and dentin-enamel junction (DEJ) structures and the linear gradation in Young’s modulus of the human bone, enamel and dentin-enamel junction, as a new material design approach, to improve the performance compared to traditional dental prostheses. Notable research is highlighted regarding application of biomimetic prostheses into various fields in dentistry. The current chapter book will open a new avenue for recent researches aimed at the further development of new dental prostheses for improving their clinical durability

High-cycle fatigue behavior of temporomandibular joint implant

The Temporomandibular Joint (TMJ) is a unique joint in the body which has a frequency of motion up to 2000 times per day. There are many TMJ disorders which can disable the joint leading to implantation of TMJ implant. Long-term follow-up of patients with TMJ implant needs to be studied for the benefit of both patients and clinicians. During the jaw movement, TMJ is subjected to varying loads which could cause fatigue failure of TMJ implant at high loading cycles. Therefore, it is important to ensure that TMJ prosthesis is protected against fatigue failure which indicates its long-term success. The aim of this study is to examine the fatigue analysis of three TMJ implants made of titanium alloy, cobalt-chromium alloy and stainless steel 316L, using finite element method. A three-dimensional model of mandible consisting of cortical and cancellous bone was developed from computed tomography images. A basic TMJ implant and fixation screws were modeled using three-dimensional modeling software. Finite element analysis of implanted mandible was done by assigning forces simulating the masticatory muscles to represent five static biting tasks. The loading configurations consisted of nine principal masticatory muscles. The results of static analysis showed that the resultant equivalent stresses in TMJ implant did not exceed the respective material’s yield stress. The safety factor of all three materials was larger than 1, which indicates sufficient strength for the five simulated clenching tasks. The Fatigue analysis showed that all three materials will never fail under fatigue. Titanium showed the best performance as it has the higher safety factor to ensure long-term success of a TMJ implant

Mechanical analysis and design of dental restorations: fatigue, mcrogap and screw loosening

256 p

Influence of Different Abutment Designs on the Biomechanical Behavior of One-Piece Zirconia Dental Implants and Their Surrounding Bone: A 3D-FEA

Background: In a dental implant/bone system, the design factors affect the value and distributions of stress and deformations that plays a pivotal role on the stability, durability and lifespan of the implant/bone system

Design e validação de um modelo de reabilitação com implantes curtos

Objectives: This research intended to develop and validate a digital model that could be used to study the stresses and strains created in the different components involved in oral fixed rehabilitations with short implants. The validated model was then used to simulate a clinical- like situation. Methods: A digital model was created considering the posterior areas of the mandible. Its materialization obtained ten specimens of the experimental prototype. Seven of them were static compressive tested until failure and, for the other three, the tests were progressively interrupted, to allow the establishment of a damage sequence. On the numerical model a finite element analysis was performed with Abaqus software, under similar conditions to the experimental situation. Results: The stress pattern on the FEA and the failure location on the static test were similar. The sequence in which each part reached the yield strength was the same as that observed on the interrupted static test (resin, prosthetic framework, implants and implant screws, in this order). Due to these results, the model was considered valid. A clinical-like simulation with the validated model showed that buccal cortical bone, around the implants platform, is the weakest part of such a rehabilitation. Conclusions: This research allowed the development and validation of a computer-aided design model that can be used to study an oral fixed rehabilitation supported by short implants. For clinical purposes, it is important to refer that the highest stress and strain values were found on the cortical bone around the buccal aspect of the implants.Objetivos: O objetivo desta investigação foi o desenvolvimento e validação experimental de um modelo digital, que permita o estudo das tensões e deformações geradas nos diferentes componentes de uma reabilitação oral fixa sobre implantes curtos. O modelo obtido foi então usado para simular uma situação clinica. Métodos: Um modelo numérico foi criado considerando a região posterior da mandibula. A sua materialização permitiu obter dez amostras do protótipo experimental. Sete delas foram sujeitas a ensaios estáticos de compressão até à falência. Nas restantes três, os ensaios foram interrompidos com forças gradualmente crescentes, estabelecendo a sequência pela qual os componentes se deformaram. O modelo numérico foi também sujeito a uma simulação com elementos finitos, usando o software Abaqus, em condições semelhantes à simulação experimental. Resultados: O padrão de tensões obtido no modelo numérico foi similar à localização das fraturas no modelo experimental. A sequência segundo a qual a tensão de cedência foi alcançada em cada parte do modelo numérico foi a mesma encontrada quando o ensaio estático se interrompeu (por esta ordem: resina, prótese, implantes e parafusos). Estes resultados permitiram considerar o modelo válido. A simulação de uma situação clínica, com o modelo validado, revelou que o osso cortical, em vestibular da plataforma dos implantes, é a região mais débil da reabilitação. Conclusões: Esta investigação permitiu o desenvolvimento e a validação de um modelo que permite o estudo de reabilitações fixas sobre implantes curtos. Clinicamente é importante realçar que o osso cortical é a zona que apresenta tensões e deformações mais elevadas. (Rev Port Estomatol Med Dent Cir Maxilofac. 2017;58(2):79-90)info:eu-repo/semantics/publishedVersio