
Gholamreza RouhiAmirkabir University of Technology | TUS · Faculty of Biomedical Engineering
Gholamreza Rouhi
PhD
Modeling bone healing and remodeling; Stability of dental implants; Continuum mechanics; Finite element analysis
About
221
Publications
125,238
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Introduction
Dr. Gholamreza Rouhi received his Ph.D. in Mechanical Engineering, major in Biomechanics, from the University of Calgary. He is now a faculty member at Amirkabir University of Technology ever since. In ODBL, Orthopedic and Dental Biomechanics Lab, at AUT, our mission is to shed light on open and unsolved questions related to the following disciplines: Mechanobiology of bone healing; Bone growth and bone remodelling theories; Bone-implants interaction; Dental implants 1ry and 2ndry stability
Additional affiliations
Education
September 2002 - May 2006
September 1995 - March 1998
September 1991 - May 1995
Publications
Publications (221)
Bone fracture healing is a complex process that ultimately results in the formation of new bone tissue. One of the most influential factors in this process is the mechanical environment at the healing site. Computational models, utilizing mechanobiological algorithms, can simulate the effects of mechanical stimuli on the differentiation of stem cel...
Primary stability, defined as the initial contact between bone and implant, is essential for the success of implantation. Surgical technique, which involves drilling and insertion, affects primary stability. Keeping a feed rate appropriate for the rotational speed is crucial for achieving optimal insertion and adequate primary stability. The insert...
In this study, the primary stability of two widely
used imported dental implants in the Iranian market, referred
to as Implant A and Implant B, was investigated and
compared. This comparison was conducted through
simulations of each implant insertion process into the bone,
followed by pull-out test simulations. Key parameters such as
maximum insert...
Intramedullary (IM) nailing and plating are two major options for the treatment of
distal tibial fractures, which each method has its own pros and cons. Bone loss due
to IM nailing or plating can be a serious concern, which may lead to the premature
failure of the implants. Thus, investigating bone remodeling in response to
orthopedic implantation...
Even though, proximal tibia is a common site of giant cell tumor and bone fractures, following tumor removal, nonetheless very little attention has been paid to affecting factors on the fracture risk. Here, nonlinear voxel-based finite element models based on computed tomography images were developed to predict bone fracture load with defects with...
Objective: The study aimed at discovering the existing differences in lower limb joints' kinematics, and EMG signals of 4 particular muscles of the ankle joint during gait, between normal subjects and patients with bilateral triple arthrodesis.
Methods: In this research, a 3D motion analysis system was used and joints’ angles were calculated using...
Primary stability is the initial mechanical engagement of the implant with its neighboring bone, which can be assessed through in-vitro assessment of stiffness and the ultimate load of the bone-implant complex. Implantation and the following loading on an implant after implantation, could cause mechanical damage in the peripheral bone, and subseque...
Primary stability of a dental implant is defined as its ability to resist the applied load without showing excessive damage in peri-implant bone, which is a prerequisite for secondary stability, and consequently for implantation success. The main goal of this study was to develop a validated micro-finite element (μFE) approach to assess the primary...
ABSTRACT
Statement of problem: Lack of knowledge regarding the optimal design of thread configuration in dental implants, which can offer a satisfactory level of stability in the implant-bone construct, is a significant challenge in the field of dental biomechanics.
Purpose: The purpose of this finite element analysis study was to identify the op...
A Keynote Talk was given at ICBME
Periodontal ligament (PDL) plays a crucial role in transferring load from tooth to its adjacent bone, and its role is more pronounced in case of trauma, due to its shock-absorbing character, which has not been fully understood yet. Different constitutive models have correlated mechanical function of PDL with its anisotropic, inhomogeneous, non-line...
The threads, as the most critical component of dental implants, transfer the imposed occlusal loads to the adjacent bone. Moreover, regulation of the mechanical stimuli in the implant adjacent bone is crucial to maximize the bone-implant construct stability. An optimal thread design can be resulted when the distribution of mechanical stimuli within...
Primary stability of dental implants is the initial mechanical engagement of the implant
with its adjacent bone. Implantation and the subsequent loading may cause
mechanical damage in the peripheral bone, which ultimately reduces the stability of the
implant. This study aimed at evaluating primary stability of dental implants through
applying stepw...
Abstract:
Bone is maintained through a coupled process of resorption and formation, in a continuous process, called bone remodelling (BR) process. When there is an imbalance in BR, bone diseases and/or implant failure may appear/occur. Because of the great importance of BR and its effects on bone diseases, as well as its crucial applications in ort...
This study investigated the effects of hydroxyapatite (HA) and hydroxyapatite/titanium
(HA/Ti) coatings on osseointegration and bonding strength at the bone-implant
interface. The coatings were made using air plasma spray (APS), and three study
groups were examined: 1) Uncoated commercial pure titanium (CP-Ti) rods; 2) HAcoated CP-Ti rods, and 3) C...
In this keynote presentation, I first provided a brief definition of Biomechanics and one of its salient feature, i.e. Remodeling of biological tissues. I will then defined bone remodeling process, and introduced some well-known continuum mechanics based models, including: Adaptive Elasticity Model of Cowin and Hegedus (1967), and two modifications...
Intramedullary (IM) nailing and plating are two major
options for the treatment of distal tibia fractures. Each
of these two approaches has its own positive aspects,
also some drawbacks. Thus, the best treatment for
fracture of the distal tibia still remains as an open
question. Bone is a living tissue and a smart structure,
which continuously upda...
Internal fixation is a prevalent surgical method for thoracolumbar burst fracture stabilization. It helps approximately 10-20% of all thoracolumbar spine fractures, which account for about 90% of all spine fractures. Prediction of the range of motion is a challenging task for surgeons which is beneficial to be evaluated before surgeries. Finite ele...
Although the anterior cruciate ligament (ACL) reconstruction using interference screw is a well-accepted surgical procedure, patients still suffer graft failure in the initial rehabilitation phase. Graft fixation stability of a newly designed anatomical hybrid thread tapered interference screw (AHTTIS) was compared with a conventional standard one...
A brief description of continuum mechanics is given, first. Then, a general introduction on biomechanics is presented, along with some salient features of it, which should be kept in mind when one is working in this field. The manuscript will continue with an introduction on bone remodelling process, then some phenomenological models on the bone re...
Performance of the locking compression plate (LCP) is a multi-factorial function. The control parameters of plating, such as geometries, material properties, and physical constraints of the LCP components, affect basic functions associated with the bone fixation, including the extent of stress shielding and subsequent bone remodeling, strength and...
This study aimed to explore the effects of drilling rotational speed and feed-rate on the stability of dental implants through in-vivo and ex-vivo experiments. To this end, a total of 16 identical dental implants were inserted in the mandible of four dogs. The osteotomies were made with two drilling rotational speeds, i.e., 800 and 1500rpm, and two...
Background: Function of periodontal ligament (PDL)-cementum enthesis (PCE) in
transferring mechanical stimuli within tooth-periodontium (PDT)-bone complex was not
made clear yet. This study aimed to evaluate the effects of PCE on the mechanical
stimuli distribution within the PDL and alveolar bone in the tooth-PDT-bone complex
under occlusal forces...
Total ankle replacement (TAR) and subtalar joint (STJ) fusion, are popular treatments for ankle osteoarthritis (OA). Short endurance limits the former, and movement disability comes with the latter. It is hypothesized here that fusion of the STJ can improve the longevity of the TAR prosthesis. In this study, a fresh human cadaver's ankle joint unde...
This study used finite element (FE) analysis to determine the
stress distribution within the growth plates (GPs) of the
growing spine under the equivalent loads (as an alternative to
in vivo loading conditions) estimated by our previouslyvalidated
trunk musculoskeletal (MS) model of normal and
scoliotic spines. Results of the present work showed th...
In order to investigate the effect of unilateral muscle weakening on the stress distribution in the growth-plates (GPs) of an adolescent idiopathic scoliosis (AIS) spine, the equivalent loads (as an alternative to in vivo loading conditions), estimated by our previously-validated trunk musculoskeletal (MS) model of AIS spine [1], were applied on th...
Background
Superior biomechanical performance of tapered interference screws, compared with non-tapered screws, with reference to the anterior cruciate ligament (ACL) reconstruction process, has been reported in the literature. However, the effect of tapered interference screw’s body slope on the initial stability of ACL is poorly understood. Thus,...
PURPOSE. Function of periodontal ligament-cementum enthesis (PCE) in transferring mechanical stimuli within tooth-periodontium (PDT)-bone complex was not made clear yet. This study aimed to evaluate the effects of PCE on the mechanical stimuli distribution within the PDL and alveolar bone in the tooth-PDT-bone complex under occlusal forces using fi...
Background
Superior biomechanical performance of tapered interference screws, in regard to reconstruction of anterior cruciate ligament (ACL), compared with non-tapered screws, has been reported in the literature. However, the effect of tapered interference screw’s body slope on the initial stability of ACL is not studied yet. Thus, the main goal o...
This study aimed at finding the acceptable range, and the optimal value for the locking compression plate (LCP) thickness (THK), through simulating the osteogenic pathway of bone healing, and by checking bone-plate construct’s strength and stability. To attain the goals of this research, a multi-objective approach was adopted, which should trade-of...
The distal femur is the predominant site for benign bone tumours and a common site for fracture following tumour removal or cementation. However, the lack of conclusive assessment criterion for post-operative fracture risk and appropriate devices for cement augmentation are serious concerns. Hence, a validated biomechanical tool was developed to as...
Surgical techniques and drilling parameters, such as rotational speed and feed-rate, have been shown to affect dental implant stability. Although thermally induced bone damage, caused during the drilling process, have been widely investigated to date, there is a dearth of knowledge regarding the mechanical effects of the drilling process on the den...
Periodontal ligament (PDL) contributes to the stability of the tooth-PDL-bone structure (T-PDL-B) under impact loading. In the case of inserting a dental implant into the bone, the dental implant-bone (DI-B) construct will be more prone to the mechanical damage caused by impact loading, compared to the T-PDL-B construct. This study aims to identify...
[This corrects the article DOI: 10.1016/j.heliyon.2020.e05210.].
The aim of this study was to investigate the effects of the substrates’ materials on the mechanical properties and behavior of hydroxyapatite (HA) coating, deposited by HVOF method. High velocity oxy-fuel (HVOF) deposition was used as the coating technique, and HA was coated on different substrates, i.e. commercial pure titanium (CPTi), Ti6Al4V, Co...
Primary stability is the initial mechanical engagement of implant with its neighboring bone, which is a prerequisite for a successful implantation. Primary stability of dental implants can be investigated through in-vitro assessment of stiffness and the ultimate load of the bone-implant complex. Implantation and the following loading on an implant...
The main goal of this study was to investigate the performance of a night-time
Providence brace, which alters stress distribution in the growth plates and ultimately
result in a reduced Cobb angle, from a biomechanical standpoint, using experimental
and in-silico tools. A patient with a mild scoliosis (Cobb angle= 17) was chosen for this
study. App...
This study aimed to investigate changes occurred in the stress distribution in the growth plates (GPs) of a trunk with adolescent idiopathic scoliosis (AIS) following unilateral muscle paralysis. We hypothesized that weakening the appropriately chosen muscles on the concave side can decelerate AIS deformity progression. Muscle forces and reaction l...
The goal of this study was to investigate two commonly used methods of fixation of distal metaphyseal tibia fractures,
plating and nailing as well as the less frequently employed nailing with Poller screws, from a biomechanical perspective.
Despite numerous studies, the best method to repair fractures of tibia the remains up for of debate. This stu...
Malalignment is a common complication in the treatment of distal fractures of tibia. Numerous efforts have been made to reduce the malalignment ratio. However, the reported cases with this disorder are still high. This study aimed at investigating an adaptive design of an intramedullary nail, with a novel interlocking mechanism (AINIM), as an alter...
PurposeEven though the regeneration of periodontium tissue (PDT) around dental implants was of interest in recent years, this process was not investigated from a biomechanical point of view, to date. The purpose of this finite element study was to assess the impact of splinting technique on the initial stability and movement pattern of a tooth-shap...
During dental trauma, periodontal ligament (PDL) contributes to the stability of the tooth-PDL-bone structure. When a dental implant is inserted into the bone, the dental implant-bone construct will be more prone to mechanical damage, caused by impact loading, than the tooth-PDL-bone construct. In spite of the prevalence of such traumas, the behavi...
Abstract
It is widely accepted that periodontal ligament (PDL) plays a crucial role in transferring load from a tooth to the alveolar bone. Finite element (FE) studies can be used to find stress and strain distribution in alveolar bone, under physiological and static loading conditions. Nonetheless, the role of PDL is even more crucial in the case...
Abstract
Intervertebral disc (IVD) is a highly specialsoft tissue that resides between two
neighboring vertebrae in the spinal column, and is responsible for load-bearing and mobility in the spine. Deformability of spine is mostly because of the presence of this structure, and thus obtaining precise mechanical behaviour of it is of great importanc...
Abstract
The success rate of dental implants depends on various factors, including implant material and structural properties, bone density, and surgical technique. Drilling, as one of the main parts of the dental implant surgery, plays a vital role in the success of implantation. Regarding the effects of drilling parameters on thermal disturbance...
During dental trauma, periodontal ligament (PDL) contributes to the stability of the tooth-PDL-bone structure. When a dental implant is inserted into the bone, the dental implant-bone construct will be more prone to mechanical damage, caused by impact loading, than the tooth-PDL-bone construct. In spite of the prevalence of such traumas, the behavi...
Lack of quantitative, biomechanical criteria to predict the risk of fracture for a bone affected by giant cell tumor (GCT) has made the decision for the necessary surgical technique a dilemma. The purpose of this study is to critically assess the usefulness of quantitative computed tomography (QCT) based structural rigidity analysis (QCSRA) and QCT...
Femoroacetabular impingement (FAI) is an interference fit between the femoral head-neck junction and the labrum of the acetabular rim caused by a morphological deformity. FAI induces a jamming sensation correlating to pain and early osteoarthritis. It is most often attributed to one’s genetics, skeletal maturation, or to a congenital deformity. It...
Bone is continuously remodeled through a coupled process of bone resorption and bone formation, and this process is called bone remodeling. An imbalance in bone remodeling may cause diseases such as osteoporosis. Bone resorption and apposition are caused by chemical reactions between cells and matrix and occur on the free surfaces. Most of the exis...
Bone is continuously remodeled through a coupled process of bone resorption and bone formation, and this process is called Bone Remodeling. When there is an imbalance in the bone remodeling, it can cause diseases; such as Osteoporosis or Osteopetrosis.
All the resorption and apposition of bone occurs on its free surfaces. In this research, we repl...
Bone is continuously remodeled through a coupled process of bone resorption and bone formation, and this process is called bone remodeling. An imbalance in bone remodeling may cause diseases such as osteoporosis. Bone resorption and apposition are caused by chemical reactions between cells and matrix. Bone is a mixture comprised of solid matrix, fl...
Bone is a dynamic structure. Its mass is correlated to the magnitude of the external loads and trabeculae are aligned with the loading direction. Bone also is an optimized structure, so it can gain maximum strength with minimum mass. Spongy (trabecular) bone is the porous bone found inside the spine and at articulating joints. Bone remodeling is th...
In this work, effects of various parameters, including regularity of sewing, distance of holes from the edge of the tissue (D), distance between holes (L), suturing pattern, and material and size of the suture on the leakage of human large intestine anastomosis site were investigated, using finite element method (FEM). The effects of various parame...
Two optimization-driven approaches were employed to develop kinematics-driven (KD) and stability-based kinematics-driven (SKD) musculoskeletal models of an adult thoracolumbar to ascertain the significance of spine stability in holding the upright-standing posture after muscular disuse atrophy. Both models were used to estimate muscle forces of the...
Cement augmentation following benign bone tumor surgery, i.e. curettage and cementation, is recommended in patients at high risk of fracture. Nonetheless, identifying appropriate cases and devices for augmentation remains debatable. Our goal was to develop a validated biomechanical tool to: predict the post-surgery strength of a femoral bone, asses...
Summary:
This study used a finite element (FE) model to determine the spinal loads, and stress distribution in the intervertebral discs (IVDs) of an adult trunk with intact, as well as with the unilaterally weakened muscles under the equivalent loading condition, as an alternative to in vivo loading conditions, which were estimated by our previous...
Summary:
In order to ascertain the significance of spine stability in holding the upright-standing posture after focal muscular disuse atrophy, two optimization-driven approaches were employed to develop kinematics-driven (KD), and stability-based kinematics-driven (SKD) musculoskeletal (MS) models of an adult thoracolumbar. Results of this work s...
Current clinical criteria for identifying bone cancer patients at high risk of fracture are not solid and comprehensive, which in many occasions result in unnecessary prophylactic stabilization. The goal of this study was to develop a validated biomechanical tool to assess bone strength, as the key determinant of its fracture risk, when the size an...
Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. Clinical outcome in these patients can be improved by optimizing surgical procedures and selecting appropriate fixation methods. The aim of this study was to develop a numerical fracture model to investigate the influ...
Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. Clinical outcome in these patients can be improved by optimizing surgical procedures and selecting appropriate fixation methods. The aim of this study was to develop a numerical fracture model to investigate the influ...
Background: Tumor curettage and cementation is a widely-used treatment of benign bone tumors in distal femur. While post-operative fracture is a common complication, no criterion or biomechanical data is available to identify patients at high risk of fracture. Since there is a strong correlation between bone strength and its fracture risk, this stu...
Background: Tumor curettage and cementation is a widely-used treatment of benign bone tumors in distal femur. While post-operative fracture is a common complication, no criterion or biomechanical data is available to identify patients at high risk of fracture. Since there is a strong correlation between bone strength and its fracture risk, this stu...
This study aimed at investigating the expression of osteoblast and chondrocyte-related genes in mesenchymal stem cells (MSCs), derived from rabbit adipose tissue, under mechanical vibration. The cells were placed securely on a vibrator’s platform and subjected to a 300 Hz of sinusoidal vibration, with a maximum amplitude of 10µm, for 45 min per day...
To date, several studies have implied the importance of early stage mechanical
stability in the bone fracture healing process. This study aimed at finding a correlation
between the predicted different tissue phenotypes in the early stages of healing and
the ultimate healing outcome. For this purpose, the process of fracture healing was
numerically...
One of the main procedures in intestinal surgery is anastomosis, which is mostly performed by stapling or hand suturing. Due to limitations of these methods, a novel automatic suturing machine was designed and fabricated in this study, equipped with a needle-driving system; a thread control mechanism, and a linear mechanism, which is applicable in...
Using a combination of musculoskeletal (MS) and finite element (FE) approach, this study aimed at: evaluating stability-based muscle forces in a spine with adolescent idiopathic scoliosis (AIS), compared to a normal spine; and consequently determining the effects of stress distribution on the growth-plates (GPs) of the growing spine. For this purpo...
The main goal of this work was to investigate the effects of implants coatings' mechanical properties and morphology on the osseointegration. In order to produce different mechanical properties of coatings, two thermal spray techniques, high velocity oxy‐fuel (HVOF) and air plasma spray (APS) were employed. Titanium pins were coated and implanted i...
Abstract
Background: Pedicle screw instrumentation is one of the most commonly used forms of stabilization. Achieving solid screw fixation within the bone presents a significant challenge to spinal surgeons. Although pure pullout is not the mode of failure seen in clinical situations, pullout testing is thought to be a good predictor of pedicle scr...
The main goal of this work was to investigate the effects of implants coatings’
mechanical properties on the osseointegration. In order to produce different mechanical
properties of coatings, two thermal spray techniques, high velocity oxy-fuel (HVOF) and
air plasma spray (APS) were employed. Titanium pins were coated and implanted into
the dis...
Giant cell tumor (GCT) is a primary and benign tumor of bone, albeit locally aggressive in some cases, such as in the epi-metaphyseal region of long bones, predominantly the distal end of femur and proximal end of tibia (1). There are a variety of treatments for a bone affected by GCT, ranging from chemotherapy, radiotherapy, embolization, and cryo...
The article “The Great Need of a Biomechanical-Based Approach for Surgical Methods of Giant Cell Tumor: A Critical Review”, written by Azadeh Ghouchani, Gholamreza Rouhi was originally published Online First without open access. After publication in volume [37], issue [4], page [454–467] the author decided to opt for Open Choice and to make the art...
BACKGROUND: Vertical femoral neck fractures in the youth could be happened in high-energy accidents, and because of dominant shearing forces, this fracture is considered as a troublesome injury with a controversy regarding selection of the best fixation method.
NTRODUCTION: Giant cell tumor (GCT) is a primary, benign tumor of bone involving long bones, predominantly the distal end of the femur. The most effective treatment for this tumor is surgery. The surgery often involves defect reconstruction following tumor removal. Reconstruction is usually accomplished with cement infilling and in the case of larg...
Arthrodesis, or fusion of subtalar joints (STJs), is a well-accepted and a routine treatment in the end stage of ankle injuries or disorder, such as arthritis or fractures. Arthrodesis can restore daily life function quickly at the expense of limiting joint motion. A triple arthrodesis (TA) consists of the surgical fusion of the talocalcaneal (TC),...
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