Bone-implant System Research Articles

Bone Density Micro-CT Assessment during Embedding of the Innovative Multi-Spiked Connecting Scaffold in Periarticular Bone to Elaborate a Validated Numerical Model for Designing Biomimetic Fixation of Resurfacing Endoprostheses.

Our team has been working for some time on designing a new kind of biomimetic fixation of resurfacing endoprostheses, in which the innovative multi-spiked connecting scaffold (MSC-Scaffold) that mimics the natural interface between articular cartilage and periarticular trabecular bone in human joints is the crucial element. This work aimed to develop a numerical model enabling the design of the considered joint replacement implant that would reflect the mechanics of interacting biomaterials. Thus, quantitative micro-CT analysis of density distribution in bone material during the embedding of MSC-Scaffold in periarticular bone was applied. The performed numerical studies and corresponding mechanical tests revealed, under the embedded MSC-Scaffold, the bone material densification affecting its mechanical properties. On the basis of these findings, the built numerical model was modified by applying a simulated insert of densified bone material. This modification led to a strong correlation between the re-simulation and experimental results (FVU = 0.02). The biomimetism of the MSC-Scaffold prototype that provided physiological load transfer from implant to bone was confirmed based on the Huber–von Mises–Hencky (HMH) stress maps obtained with the validated finite element (FE) model of the problem. The micro-CT bone density assessment performed during the embedding of the MSC-Scaffold prototype in periarticular bone provides insight into the mechanical behaviour of the investigated implant-bone system and validates the numerical model that can be used for the design of material and geometric features of a new kind of resurfacing endoprostheses fixation.

Development of an Instrument to Assess the Stability of Cementless Femoral Implants Using Vibration Analysis During Total Hip Arthroplasty.

Objective: The level of primary implant fixation in cementless total hip arthroplasty is a key factor for the longevity of the implant. Vibration-based methods show promise for providing quantitative information to help surgeons monitor implant fixation intraoperatively. A thorough understanding of what is driving these changes in vibrational behavior is important for further development and improvement of these methods. Additionally, an instrument must be designed to enable surgeons to leverage these methods. This study addresses both of these issues. Method: An augmented system approach was used to develop an instrument that improves the sensitivity of the vibrational method and enables the implementation of the necessary excitation and measurement equipment. The augmented system approach took into account the dynamics of the existing bone-implant system and its interaction with the added instrument. Results: Two instrument designs are proposed, accompanied by a convergence-based method to determine the insertion endpoint. The modal strain energy density distribution was shown to affect the vibrational sensitivity to contact changes in certain areas. Conclusion: The augmented system approach led to an instrument design that improved the sensitivity to changes in the proximal region of the combined bone-implant-instrument system. This fact was confirmed both in silico and in vitro. Clinical Impact: The presented method and instruments address practical intraoperative challenges and provide perspective to objectively support the surgeon’s decision-making process, which will ensure optimal patient treatment.

Comparison of femur strain under different loading scenarios: Experimental testing.

Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.

Modeling of Dental Implant Osseointegration Progress by Three-Dimensional Finite Element Method

As osseointegration is a time-dependent process, biomechanical assessment is thought to determine whether a fibrous encapsulation or a bone covering will develop around an implant, according to the stress in the implant and surrounding bone. This study proposes a model for stress evaluation by finite element method (FEM) during the osseointegration progress, the main factor implied in implant success or failure. The loadings due to masticatory forces generate stress concentration and consequently, an adequate risk concerning the implant stability should be assessed. An accurate FEM model is used to calculate the stress and displacement in the whole implant–bone system during the osseointegration progress. This process is simulated by taking into account the gradual increase in the damaged biomechanical properties of the cortical bone. The results reveal that as the implant osseointegration occurs gradually, the bone stiffness from the peri-implant area increases gradually, such that in the end (healing) we observed that the cortical bone begins to take over the bending loading. In addition, the displacements decrease as the osseointegration gradually occurs and the cortical bone stress reaches higher values, which are placed in the mandibular ridge. The FEM is suitable to model the osseointegration progress, offering valuable information concerning the stress concentration zones in the implant–bone system and consequently, the risk evaluation, both for pre- and post-osseointegration.

Mechanical properties of the bone-implant systems in conditions of the stable functional osteosynthesis

Fractures of the diaphysis of leg bones make up 45% of all long bone fractures, they are one the most common injuries to the bones of the limb segments, the treatment of which is accompanied by a large number of complications, therefore the problem of improving the treatment of patients with this injury is still relevant for present traumatology and orthopedics. The use of compression distraction systems, intramedullary and extramedullary osteosynthesis systems allows a stable functional osteosynthesis and eliminates the need for additional gypsum immobilization of a segment or limb in the postoperative period. Biomechanical relations in the bone-implant system in conditions of a stable functional osteosynthesis constitute an important factor allowing to objectify the mode of motion rehabilitation in the early postoperative period. This work studies the results of the comparative bench tests of groups of cadaver tibia in experimental injuries of type 42 A 1.1. (according to the Association for Study of Internal Fixation (AO/ASIF)) synthesized with different types of implants, such as Fixion expanding system of fixation, external fixation devices, Limited Contact Dynamic Compression Plate (LC-DCP) and blocked intramedullary osteosynthesis system (BIOS)). Each system was axially compressed using INSTRON 1185. Resistance to axial compression has been analyzed. It is noted that all these types of fixations increase the strength of the systems in the range of 22–81% compared to the intact specimens. Intraosseous fixation systems demonstrated the highest strength, which has the most optimal biomechanical relations in the bone-implant system, allowing to objectify the regime of motion rehabilitation.

Explicit finite element analysis can predict the mechanical response of conical implant press-fit in homogenized trabecular bone

Prediction of primary stability is a major challenge in the surgical planning of dental and orthopedic implants. Computational methods become attractive to estimate primary stability from clinical CT images, but implicit finite element analysis of implant press-fit faces convergence issues due to contact and highly distorted elements. This study aims to develop and validate an explicit finite element method to simulate the insertion and primary stability of a rigid implant in a deformable bone while accounting for damage occurring at the bone-implant interface. Accordingly, a press-fit experiment of a conical implant into predrilled bovine trabecular bone was designed and realized for six samples. A displacement-driven cyclic protocol was used to quantify the reaction force and stiffness of the bone-implant system. Homogenized finite element analyses of the experiments were performed by modeling contact with friction and converting an existing constitutive model with elasto-plasticity and damage of bone tissue to be applicable to an explicit time integration scheme where highly distorted elements get deleted. The computed reaction forces and unloading stiffnesses showed high correlations (R2 = 0.95 and R2 = 0.94) with the experiment. Friction between bone and implant exhibited a strong influence on both reaction force and stiffness. In conclusion, the developed explicit finite element approach with frictional contact and element deletion accounts properly for bone damage during press-fit and will help optimizing dental or orthopedic implant design towards maximal primary stability.

3D-FEA of Implant Thread Depth and Pitch on Interfacial Stresses

Objective: Using the numerical analysis, the interfacial stresses with various thread depths and pitches implants are evaluated in mandibular bone mass. Methods: Implant parameters considered herein include the thread depths of 0.30, 0.35, 0.40, 0.45, 0.50 and 0.55 mm and the pitches of 0.75, 0.80, 1.0 and 1.25 mm. A simplified bone-implant system is created by Geomagic studio and Solidworks. ANSYS workbench was used to analyze the effects of the stress distribution. Results: The maximum von Mises was exhibited in three position at the implant: the location between implant and abutment, the area between implant and screw and the threaded implant body (connect area between first thread and second thread or second thread and third thread). whereas uneven stress distribution were showed in both cortical bone and trabecular bone under oblique and vertical loading. Conclusions: This study found that the force (magnitude and direction) is the important factor of influence on stress, for biomechanical context, the ratio of the thread depth to the pitch at the implant below 0.55 is more appropriate for controlling the max EQV of implants.

MATHEMATICAL MODELING OF THE STRESS-STRAIN STATE OF THE “BONE-IMPLANT” SYSTEM DURING THE OSTEOSYNTHESIS WITH A PHILOS WITH POLYLACTIC ACID IMPLANTS

The aim: To study was to use mathematical modeling in assessing the stress-strain state of the bone-implant system during plate osteosynthesis with a PHILOS plate of a proximal humerus fracture with polylactic acid implants. Materials and methods: Two bone-implant systems with a three-fragment humerus fracture according to the Neer classification (type 11-C1 according to the AO / ASIF classification) were selected for the study, one of which was with additional reinforcement of the head fragment with two polylactic acid implants (PLA - polylactide Ingeo™ Biopolymer 4032D). Sawbones (Europe AB, Malmö, Sweden) built the humeral model on 3D scanning of the composite model № 3404 of the left humerus. Results: A comparative analysis of the obtained results of mathematical modeling of the stress-strain state of the bone-implant systems showed that with given constraints (hand abduction to 90°), the use of two polylactic acid implants can reduce the stress in the plate and screws, respectively, by 11% and 6% . Conclusions: The use of polylactic acid implants during osteosynthesis of three- and four-fragment fractures of the proximal humerus, especially in the case of osteoporosis, allows providing for the reinforcement of metal structures and supporting of the articular surface without deterioration of fixation rigidity.

Stress State of a Threaded Joint in a Dental Implant–Bone System*

The load distribution over the turns of an implant–bone threaded joint is studied. Such a joint is modeled by a rod structure in which the functional axial force is transferred from the compressed-rod–implant system to the stretched-rod–bone system through thread turns. The turns are modeled by cantilever beams attached to the implant and bone rods. Differential equation describing the intensity of distribution of the axial force is derived in a closed form. The proposed approach to determining the distribution of the load over the thread of the implant–bone joint can be used to determine the stress state of the joint, improve its design, and increase the service life of dental prostheses.

Finite-Element Study of Biomechanical Explanations for Bone Loss around Dental Implants.

Since the advent of osteointegrated implantology and its precepts issued by the Swedish School, assessment of peri-implant bone loss criteria has often been debated by professionals in this field. Long-term success of dental implants is highly reliant on structural and functional osseointegration between implant and surrounding intraoral tissues. In this context, the current study aims to provide biomechanical explanations for causes of bone loss around the dental implant after osseointegration by computational analysis, using a three-dimensional finite-element (FE) method. We design an approximate virtual model that includes the smooth, cylindrical dental implant and alveolar bone. We use SolidWorks software and export to ABAQUS for computational stress analysis at the bone-implant interface. The numerical model is created and loaded with a compressive occlusal force that is applied at the top of the implant platform. We thoroughly investigate the generated FE results and stress responses of the bone-implant system. The developed model is extremely useful for indicating biomechanical phenomena in the bone-implant interface that play a key part in bone loss around the dental implant. In addition, obtained results tend to deliver an improved understanding to designers in the biomedical engineering field and in dentistry.

Periprosthetic bone response to axial loading following TKR

PurposeThe purpose of this paper is to investigate by means of finite element analysis (FEA), the effect of polyethylene insert thickness and implant material, under axial loading following TKA.Design/methodology/approachThe 3D geometric model of bone was processed using the CT scan data by MIMICS (3matic Inc.), package. Implant components were 3D scanned and subsequently 3D modeled using ANSYS Spaceclaim and meshed in Hypermesh (Altair Hyperworks). The assembled, meshed bone-implant model was then input to ABAQUS for FE simulations, considering axial loading.FindingsPolyethylene insert thickness was found to have very little or no significance (p>0.05) on the mechanical performance, namely, stress, strain and stress shielding of bone-implant system. Implant material was found to have a very significant effect (p<0.05) on the performance parameters and greatly reduced the high stress zones up to 60 percent on the tibial flange region and periprosthetic region of tibia.Originality/valueVery few FEA studies have been done considering a full bone with heterogeneous material properties, to save computational time. Moreover, four different polyethylene insert thickness with a metal-backed and all-poly tibial tray was considered as the variables affecting the bone-implant system response, under static axial loading. The authors believe that considering a full bone shall lead to more precise outcomes, in terms of the response of bone-implant system, namely, stress, strains and stress shielding in the periprosthetic region, to loading.

A review on the latest advancements in the non-invasive evaluation/monitoring of dental and trans-femoral implants.

Dental implants and transcutaneous prostheses (trans-femoral implants) improve the quality of life of millions of people because they represent the optimal treatments to edentulism and amputation, respectively. The clinical procedures adopted by surgeons to insert these implants are well established. However, there is uncertainty on the outcomes of the post-operation recovery because of the uncertainty associated with the osseointegration process, which is defined as the direct, structural and functional contact between the living bone and the fixture. To guarantee the long-term survivability of dental or trans-femoral implants doctors sometimes implement non-invasive techniques to monitor and evaluate the progress of osseointegration. This may be done by measuring the stability of the fixture or by assessing the quality of the bone-fixture interface. In addition, care providers may need to quantify the structural integrity of the bone-implant system at various moments during the patients recovery. The accuracy of such non-invasive methods reduce recovery and rehabilitation time, and may increase the survival rate of the therapies with undisputable benefits for the patients. This paper provides a comprehensive review of clinically-approved and emerging non-invasive methods to evaluate/monitor the osseointegration of dental and orthopedic implants. A discussion about advantages and limitations of each method is provided based on the outcomes of the cases presented. The review on the emerging technologies covers the developments of the last decade, while the discussion about the clinically approved systems focuses mostly on the latest (2017-2018) findings. At last, the review also provides some suggestions for future researches and developments in the area of implant monitoring.

Design of Improved Intertrochanteric Fracture Treatment (DRIFT) Study: Protocol for Biomechanical Testing and Finite Element Analysis of Stable and Unstable Intertrochanteric Fractures Treated With Intramedullary Nailing or Dynamic Compression Screw.

BackgroundIntertrochanteric hip fractures rank in the top 10 of all impairments worldwide in terms of loss in disability-adjusted years for people aged older than 60 years. The type of surgery is usually carried out with dynamic hip screw (DHS) devices or cephalomedullary nails (CMN). Cut-out of the hip screw is considered the most frequent mechanical failure for all implants with an estimated incidence ranging from 2% to 16.5%; this entails both enhancing our understanding of the prognostic factors of cut-out and improving all aspects of intertrochanteric fracture treatment.ObjectiveThe Design of Improved Intertrochanteric Fracture Treatment (DRIFT) study’s main objective is to provide intertrochanteric fracture treatment expertise, requirements and specifications, clinical relevance, and validation to improve treatment outcomes by developing a universal algorithm for designing patient- and fracture-oriented treatment. The hypothesis to be tested is that a more valgus reduction angle and implants of higher angles will lead to a more favorable biomechanical environment for fracture healing—that is, higher compressive loads at the fracture site with lower shear loads at the hip screw femoral head interface. A new implant with enhanced biomechanical and technical characteristics will be designed and fabricated; in addition, an integrated design and optimization platform based on computer-aided design tools and topology optimization modules will be developed.MethodsTo test this hypothesis, a biomechanical study comprising experimental loading of synthetic femora (Sawbones Inc) and finite element analysis (FEA) will be conducted. Detailed FEA of existing implants (DHS and CMN) implemented in different clinical cases under walking conditions will be performed to derive the stress and strain fields developed at the implant-bone system and identify critical scenarios that could lead to failure of therapy. These models would be validated against instrumented mechanical tests using strain gages and a digital image correlation process.ResultsAfter testing, geometric drawbacks of existing implants will be fully recognized, and geometric characteristics will be correlated with critical failure scenarios. The last step would be the numeric design, computer-aided design (using FEA codes and design packages), and optimization of the new proposed implant with regard to improved biomechanical surgical technique and enhanced mechanical performance that will reduce the possibility for critical failure scenarios.ConclusionsThe optimization of the biomechanical behavior of the fracture-osteosynthesis model by the application of the ideal reduction angle and implant is expected to have a positive effect to the rate of mechanical failure and, subsequently, the healing rates, morbidity, and mortality in this fragile patient group.International Registered Report Identifier (IRRID)DERR1-10.2196/12845

Influence of Implant Length and Associated Parameters Upon Biomechanical Forces in Finite Element Analyses: A Systematic Review.

The aim of this systematic review is to provide an overview of finite element analyses comparing standard and short dental implants concerning biomechanical properties and to detect the most relevant parameters affecting periimplant stress concentrations. After screening the literature and assessment of studies, 36 studies were included in this review. Eighty-three percent of the studies state that short dental implants have to bear higher stress concentrations compared with standard length implants. At the same time, 44% of articles note that implant diameter can be considered a more effective design parameter than implant length to reduce stress concentrations and to avoid an overload of periimplant bone. Regardless of implant dimension, in all studies, the highest stress concentrations are found in the cortical section around the upper part of the implant. Unaffected of bone quality, implant diameter is found to play a key role to minimize periimplant stress concentrations. Concerning stress reduction implant length gains increasing relevance with decreasing bone density. Furthermore, splinting of short implants constitute an appropriate tool to avoid crestal overloading.

Contact phenomena modeling in biological structures on the example of the implant-bone

Abstract The work presents modeling of interface phenomena in biological structures. Selected ways of numerical modeling of phenomena at the boundary of two materials by means of FEM methods are discussed. The work focuses on phenomena related to biological structures and their mutual interactions. Using an example of an implant-bone system, various techniques of modeling interface phenomena are compared and referred to experimental results. The study reveals the main features of the selected modeling techniques, e.g. complexity of creating the model, time-consumption of computation, reliability of the obtained results. The obtained results proved that the most advantageous method is the one that makes it possible to regard interactions as numerical values, without an excessive generation of the finite elements (the grid) at the materials boundary. The contact modeling technique based on the contact indicator showed the lowest value of standard deviation in relation to contact modeling techniques: with the use of elastic-damping elements, based on the so-called boundary slip line and based on the so-called bio-layer. The contact indicator should be understood as a numerical value describing the interaction of the boundary surfaces of two objects cooperating with each other. The value of the indicator was determined experimentally. The value have oscillated +/- 0.0012mm. This is a very small value knowing that the standard deviation for the modeling technique of the contact employing damping-elastic elements gives a spread of +/- 0,1442 mm.

“Peroperative estimation of bone quality and primary dental implant stability”

ObjectivesDental implants are widely used to restore function and appearance. It may be essential to choose the appropriate drilling protocol and implant design in order to optimise primary stability. This could be achieved based on an assessment of the implantation site with respect to bone quality and objective biomechanical descriptors such as stiffness and strength of the bone-implant system. The aim of this ex vivo study is to relate these descriptors with bone quality, with a pre-implantation indicator of implant stability: pilot-hole drilling force (Fdrilling), and with two post-implantation indicators: maximal implantation torque (Timplantation) and resonance frequency analysis (RFA). MethodsEighty trabecular bone specimens were cored from human vertebrae and bovine tibiae. Bone volume fraction (BV/TV), a representative for bone quality, was obtained through micro-computed tomography scans. Implants were kept in controlled laboratory conditions following standard surgical procedures. Forces and torques were recorded and RFA was assessed after implantation. Off-axis compression tests were conducted on the implants until failure. Implant stability was identified by stiffness and ultimate force (Fultimate). The relationships between BV/TV, Stiffness, Fultimate and Fdrilling, Timplantation, RFA were established. ResultsFdrilling correlated well with BV/TV of the implantation site (r2 = 0.81), stiffness (r2 = 0.75) and Fultimate (r2 = 0.80). Timplantation correlated better with stiffness (r2 = 0.86) and Fultimate (r2 = 0.94) than RFA (r2 = 0.77 and r2 = 0.74, respectively). ConclusionOur results indicate that BV/TV and bone-implant stability can be directly estimated by the force needed for the pilot drilling that occurs during the site preparation before implantation. Moreover, implantation torque outperforms RFA for evaluating the mechanical competence of the bone-implant system.

A comparative finite element simulation of stress in dental implant–bone interface using isotropic and orthotropic material models in three mastication cycles

Although functionally graded biomaterials (FGBMs) have recently been employed in the dental implants, the role of mechanical complications in the FGBMs, i.e., isotropicity or orthotopicity, has not been well understood. This study, hence, was aimed at investigating the effects of a special type of FGBM implant in stress distribution of bone–implant interface using finite element method. Meanwhile, the effects of simplifications, such as presuming isotropic material model instead of an orthotropic one for a jaw bone, and applying a small deflection effect as a replacement for a large deflection effect in the stress–strain calculation were also examined. The results revealed that the FGBM implants can diminish the maximum stress in the implant–bone interface. In addition, although the amount of maximum strain in the bone and implant were low, considering a small deflection effect instead of a large deflection one showed to have a considerable influence in the stress and the displacement of the implant–bone system. The orthotropic bone also indicated a large amount of stress compared with the isotropic one which implies the importance of material models in simulating the stresses and displacements of the implant–bone system. These results have implications not only for understanding the stresses and displacements in the implant–bone interface, but also for providing a comprehensive information for the biomechanical experts to pay enough attention to the material models being employed in their numerical simulations.

Modal analysis for implant stability assessment: Sensitivity of this methodology for different implant designs

ObjectiveTo investigate the influence of implant design on the change in the natural frequency of bone-implant system during osseointegration by means of a modal 3D finite element analysis. MethodsSix implants were considered. Solid models were obtained by means of reverse engineering techniques. The mandibular bone geometry was built-up from a CT scan dataset through image segmentation. Each implant was virtually implanted in the mandibular bone. Two different models have been considered, differing in the free length of the mandibular branch (‘long branch’ and ‘short branch’) in order to simulate the variability of boundary conditions when performing vibrometric analyses. Modal analyses were carried out for each model, and the first three resonance frequencies were assessed with the respective vibration modes. ResultsWith reference to the ‘long branch’ model, the first three modes of vibration are whole bone vibration with minimum displacement of the implant relative to bone, with the exception of the initial condition (1% bone maturation) where the implant is not osseointegrated. By contrast, implant displacements become relevant in the ‘short branch’ model, unless osseointegration level is beyond 20%. The difference between resonance frequency at whole bone maturation and resonance frequency at 1% bone maturation remained lower than 6.5% for all modes, with the exception of the third mode of vibration in the ‘D’ implant where this difference reached 9.7%. With reference to the ‘short branch’, considering the first mode of vibration, 61–68% of the frequency increase was achieved at 10% osseointegration; 72–79% was achieved at 20%; 89–93% was achieved at 50% osseointegration. The pattern of the natural frequency versus the osseointegration level is similar among different modes of vibration. SignificanceResonance frequencies and their trends towards osseointegration level may differ between implant designs, and in different boundary conditions that are related to implant position inside the mandible; tapered implants are the most sensitive to bone maturation levels, small implants have very little sensitivity. Resonance frequencies are less sensitive to bone maturation level beyond 50%.

A nonlinear homogenized finite element analysis of the primary stability of the bone-implant interface.

Stability of an implant is defined by its ability to undergo physiological loading-unloading cycles without showing excessive tissue damage and micromotions at the interface. Distinction is usually made between the immediate primary stability and the long-term, secondary stability resulting from the biological healing process. The aim of this research is to numerically investigate the effect of initial implantation press-fit, bone yielding, densification and friction at the interface on the primary stability of a simple bone-implant system subjected to loading-unloading cycles. In order to achieve this goal, human trabecular bone was modeled as a continuous, elasto-plastic tissue with damage and densification, which material constants depend on bone volume fraction and fabric. Implantation press-fit related damage in the bone was simulated by expanding the drilled hole to the outer contour of the implant. The bone-implant interface was then modeled with unilateral contact with friction. The implant was modeled as a rigid body and was subjected to increasing off-axis loading cycles. This modeling approach is able to capture the experimentally observed primary stability in terms of initial stiffness, ultimate force and progression of damage. In addition, it is able to quantify the micromotions around the implant relevant for bone healing and osseointegration. In conclusion, the computationally efficient modeling approach used in this study provides a realistic structural response of the bone-implant interface and represents a powerful tool to explore implant design, implantation press-fit and the resulting risk of implant failure under physiological loading.

Biomechanical analysis of a radial functionally graded dental implant–bone system under multi-directional dynamic loads

Development of new biomaterials such as FGBMs for dental clinical implant applications have been recently attracted a lot of attention due to their advantages and abilities in satisfying both mechanical and biocompatibility properties simultaneously. Drawing inspiration from the geometry of a real dental implant system, and using the properties of radial functionally graded biomaterials, a model was investigated to fabricate the artificial FGBM dental implant under periodic dynamic loads. The investigation is done using a finite element analyzer, and the problem is solved under the actual bone geometry, constraints, conditions and combined dynamic loads. The effects of radial FGBM dental implants on the stress and deformation values near the dental implant–bone interface under periodic dynamic loads are simulated. Response characteristics of FGBM implant models with different heterogeneous biomaterial parameters are determined and compared to the behavior of conventional titanium and titanium coated by a film of hydroxyapatite implants. The results show that using radial FGBM dental implants can improve the mechanical behaviors of dental implant systems regarding stress and deformation. It was also found that FGBM parameters can play an essential role in achieving an efficient biomechanical function in those systems.