Remodeling of the Mandibular Bone Induced by Overdentures Supported by Different Numbers of Implants

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Kai Li ◽  
Haitao Xin ◽  
Yanfang Zhao ◽  
Zhiyuan Zhang ◽  
Yulu Wu
Keyword(s):  
Bone Density ◽  
Bone Remodeling ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Neck Region ◽  
Mandibular Bone ◽  
Occlusal Force ◽  
User Material Subroutine ◽  
Edentulous Patients ◽  
Almost All

The objective of this study was to investigate the process of mandibular bone remodeling induced by implant-supported overdentures. computed tomography (CT) images were collected from edentulous patients to reconstruct the geometry of the mandibular bone and overdentures supported by implants. Based on the theory of strain energy density (SED), bone remodeling models were established using the user material subroutine (UMAT) in abaqus. The stress distribution in the mandible and bone density change was investigated to determine the effect of implant number on the remodeling of the mandibular bone. The results indicated that the areas where high Mises stress values were observed were mainly situated around the implants. The stress was concentrated in the distal neck region of the distal-most implants. With an increased number of implants, the biting force applied on the dentures was almost all taken up by implants. The stress and bone density in peri-implant bone increased. When the stress reached the threshold of remodeling, the bone density began to decrease. In the posterior mandible area, the stress was well distributed but increased with decreased implant numbers. Changes in bone density were not observed in this area. The computational results were consistent with the clinical data. The results demonstrate that the risk of bone resorption around the distal-most implants increases with increased numbers of implants and that the occlusal force applied to overdentures should be adjusted to be distributed more in the distal areas of the mandible.

Analogy of Strain Energy Density Based Bone-Remodeling Algorithm and Structural Topology Optimization

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
In Gwun Jang ◽  
Il Yong Kim ◽  
Byung Man Kwak
Keyword(s):  
Topology Optimization ◽  
Energy Density ◽  
Bone Remodeling ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Optimization Method ◽  
Bone Adaptation ◽  
Structural Topology Optimization ◽  
Structural Topology ◽  
Topology Optimization Method

In bone-remodeling studies, it is believed that the morphology of bone is affected by its internal mechanical loads. From the 1970s, high computing power enabled quantitative studies in the simulation of bone remodeling or bone adaptation. Among them, Huiskes et al. (1987, “Adaptive Bone Remodeling Theory Applied to Prosthetic Design Analysis,” J. Biomech. Eng., 20, pp. 1135–1150) proposed a strain energy density based approach to bone remodeling and used the apparent density for the characterization of internal bone morphology. The fundamental idea was that bone density would increase when strain (or strain energy density) is higher than a certain value and bone resorption would occur when the strain (or strain energy density) quantities are lower than the threshold. Several advanced algorithms were developed based on these studies in an attempt to more accurately simulate physiological bone-remodeling processes. As another approach, topology optimization originally devised in structural optimization has been also used in the computational simulation of the bone-remodeling process. The topology optimization method systematically and iteratively distributes material in a design domain, determining an optimal structure that minimizes an objective function. In this paper, we compared two seemingly different approaches in different fields—the strain energy density based bone-remodeling algorithm (biomechanical approach) and the compliance based structural topology optimization method (mechanical approach)—in terms of mathematical formulations, numerical difficulties, and behavior of their numerical solutions. Two numerical case studies were conducted to demonstrate their similarity and difference, and then the solution convergences were discussed quantitatively.

New aspects of the trabecular bone remodeling regulatory model resulting from the shape optimization studies

2019 ◽  
Vol 234 (3) ◽  
pp. 282-288
Author(s):  
Michał Nowak ◽  
Jan Sokołowski ◽  
Antoni Żochowski
Keyword(s):  
Energy Density ◽  
Shape Optimization ◽  
Trabecular Bone ◽  
Bone Remodeling ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Natural Phenomenon ◽  
Bone Surface ◽  
Clinical Observations ◽  
Trabecular Bone Remodeling

The trabecular bone can adapt its form to mechanical loads and form structures that are both lightweight and very stiff. In this sense, it is a problem similar to structural optimization, especially topology optimization. The natural phenomenon leading to mechanical optimization of the bone structures is called trabecular bone remodeling. The main assumption and the benchmark for the numerical models of the phenomenon is the observation that the strain energy density on the structural surface is constant. This constant value corresponds to the homeostatic strain energy density, the state of bone tissue with a perfect balance of the loss, and gain of the bone mass. We assumed that the trabecular bone can form an optimal structure. The idea behind the investigation is to carry out studies on the ground of mechanics and to interpret clinical observations in the context of the results obtained from the optimization studies. In this way, clinical observations have been confirmed by strict arguments based on mechanics, leading to the unequivocal conclusion that equalization of the strain energy density on the trabecular bone surface allows minimizing the strain energy in the whole structure of the bone. This proves the veracity of the assumption that the remodeling process leads to the formation of the structure with the highest stiffness. In addition, this article elaborates on two new aspects of the remodeling phenomenon resulting directly from the considerations in the field of shape optimization important for numerical simulation. The first one concerns the influence of surface curvature on the remodeling process. The second one concerns the role of the bone surface where different loads are analyzed. Both aspects show the need of actual trabecular bone geometry model for the simulation of the trabecular bone remodeling phenomenon.

scholarly journals Influence of the Temporomandibular Joint in the Estimation of Bone Density in the Mandible through a Bone Remodelling Model

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Maria S. Commisso ◽  
Joaquín Ojeda ◽  
Juana Mayo ◽  
Javier Martínez-Reina
Keyword(s):  
Bone Density ◽  
Temporomandibular Joint ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Bone Remodelling ◽  
Realistic Model ◽  
Mechanical Stimulus ◽  
Finite Element Models ◽  
Articular Disc ◽  
Detailed Model

The temporomandibular joint (TMJ) plays a key role in the distribution of stresses in the mandible during mastication and consequently in the distribution of bone density, due to the interconnection between both variables through bone remodelling. Two finite element models of the mandible were compared to study the influence of the redistribution of stresses produced by the joint: (1) a model without TMJ, but with simplified boundary conditions to replace the joint, as done in previous models; (2) a more realistic model including the articular disc and some ligaments present in the TMJ. The stresses and strains in both models were compared through the strain energy density, used in many bone remodelling models as a measure of the mechanical stimulus. An anisotropic bone remodelling model was used to simulate the behaviour of mandible bone and to estimate its density distribution. The results showed that the TMJ strongly affects the stress distribution, the mechanical stimulus, and eventually the bone density, and not only locally in the condyle, but also in the whole mandible. It is concluded that it is utterly important to include a detailed model of the TMJ to estimate more correctly the stresses in the mandible during mastication and, from them, the bone density and anisotropy distribution.

Bone Remodeling Algorithm Incorporating Various Quantities as Mechanical Stimulus and Assuming Initial Microcrack in Bone

2017 ◽  
Vol 754 ◽  
pp. 189-193
Author(s):  
Libor Borák ◽  
Petr Marcián
Keyword(s):  
Finite Element ◽  
Bone Resorption ◽  
Energy Density ◽  
Bone Remodeling ◽  
Material Properties ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Mechanical Stimulus ◽  
Coupled Processes ◽  
Bone Damage

It is widely accepted that bones have the ability to adapt to new biomechanical environment by changing their material properties, geometry and inner architecture. Bones have also an exceptional ability to self-repair, to remove microcracks and to prevent the bone damage caused by the fatigue failure. These abilities are enabled through coupled processes of bone resorption and bone formation, the processes collectively referred to as bone remodeling. Numerous studies have shown that bone remodeling is governed by combination of mechanical stimulus (strains) and its frequency, both sensed by sensor cells (osteocytes). Through mechanotransduction, the stimulus is transmitted to actor cells (osteoclasts, osteoblasts) that actually do the bone resorption or formation. Several theories have been proposed to predict bone remodeling and several finite-element-based algorithms have been introduced. The vast majority of them uses strain energy density as the mechanical stimulus. The purpose of this paper is to investigate and discuss the applicability of also other strain-based representations of the mechanical stimulus in simulations of remodeling of bone with an initial microcrack. The need for developing more reliable models is essential for both clinicians and engineers who are interested, for instance, in prediction of bone performance when various implants are involved.

scholarly journals Effects of calcitonin and calcium medication in treatment of edentulous osteoporotic mandible

2013 ◽  
Vol 70 (6) ◽  
pp. 576-579
Author(s):  
Srdjan Postic
Keyword(s):  
Bone Density ◽  
Suitable Method ◽  
Control Group ◽  
Skeletal Density ◽  
Mandibular Bone ◽  
Panoramic Radiographs ◽  
Radiographic Outcomes ◽  
Consequent Reduction ◽  
Edentulous Patients ◽  
Experimental Group

Background/Aim. In addition to damage of the bones that support the remaining teeth, degradation of osteoporotic oral bones also lead to a consequent reduction of supporting tissues and the loss of dentures retention. The aim of this study was to assess the clinical and radiographic outcomes following injection of a calcitonin and calcium solution into the buccal aspects of edentulous mandibles. Methods. The experimental group of 67 edentulous patients diagnosed with osteoporosis, and the control group of 19 nonosteoporotic edentulous patients were treated with the calcitonin and calcium once solution per month. Mandibular bone density was measured from panoramic radiographs, supplemented by T scores of skeletal density in the experimental group. Results. After the therapy, measurements showed moderate increases in bone density, compensating for up to 4% of the total loss of minerals and solidity of denture-bearing areas of osteoporotic mandibles. Osteoporosis affected women earlier than men in this study. Conclusion. Application of a calcitonin and calcium solution is a suitable method of preprosthetic therapy for edentulous osteoporotic patients.

scholarly journals Effect of mandibular complete dentures relining on occlusal force distribution using T-scan system

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Eman M. Ibraheem ◽  
Hisham S. ElGabry
Keyword(s):  
Trial Registration ◽  
Force Distribution ◽  
Complete Dentures ◽  
Clinical Trial Registration ◽  
Occlusal Force ◽  
Left Posterior ◽  
Before And After ◽  
Soft Denture Liner ◽  
Edentulous Patients ◽  
Posterior Area

Abstract Background This study aimed to evaluate the effect of mandibular complete dentures relining using soft relining material on the distribution of various occlusal forces using T-Scan system. Fifty completely edentulous patients having their conventional complete dentures earlier fabricated and utilized were selected for this study. Patients were controlled diabetics, characterized by having their residual alveolar ridges moderately developed and lined with firm mucoperiosteum. Mandibular complete dentures were relined with soft denture liner and T-Scan device was used for occlusal force distribution measurement prior to denture relining and three months thereafter the relinning procedure. Results Comparison between occlusal forces percentages before and after denture relining revealed that occlusal forces percentages was significantly lower after denture relining in anterior area, significantly higher after denture relining in right posterior area, where it was insignificantly higher after relining in left posterior area. Conclusions Our findings revealed that the use of soft denture liner for mandibular complete denture relining significantly improved the occlusal load distribution. Clinical trial registration Trial registration NCT, NCT04701970. Registered 23/11/2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04701970

scholarly journals Volume free strain energy density method for applications to blunt V-notches

2020 ◽  
Vol 28 ◽  
pp. 734-742
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Liviu Marsavina ◽  
Filippo Berto
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Density Method ◽  
Free Strain

scholarly journals On the application of the volume free strain energy density method to blunt V-notches under mixed mode condition

2021 ◽  
Vol 230 ◽  
pp. 111716
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Majid Reza Ayatollahi ◽  
Liviu Marsavina ◽  
Filippo Berto
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Mixed Mode ◽  
Strain Energy ◽  
Density Method ◽  
Free Strain

scholarly journals A numerical analysis of skin–PPE interaction to prevent facial tissue injury

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rikeen D. Jobanputra ◽  
Jack Hayes ◽  
Sravani Royyuru ◽  
Marc A. Masen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Tissue Injury ◽  
Soft Materials ◽  
Element Model ◽  
Healthcare Systems ◽  
Skin Injury ◽  
Energy Density Distribution ◽  
The World ◽  
The Face

AbstractThe use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on healthcare systems around the world, leading to medical professionals using high-grade PPE for prolonged durations, resulting in device-induced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometric and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviour (e.g. many elastomers) should be avoided.

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