finite element analysis of dental implant
TRANSCRIPT
CADMMST2015
Submission of project
Presenter
Shiladitya Paul 15MM60005 mmst 1st sem. School of medical science & techn. iit kgp
Under guidance of
Prof, Arghya Deb
Ph.D.(Princeton Univ)
Associate Professor, Civil EngineeringCo-Prof-in-Charge, Centre for Railway Research, Civil Engineering,
IIT KGP
Project Title
•Finite Element Analysis of Dental Implant Using Abaqus Software
What is A Dental Implant?
• Development of an ideal substitute for missing teeth has been one of the long-term aims of dentistry. A dental implant is a biocompatible screw-like titanium ‘fixture’ that is surgically placed into the jawbone.
• An implant post or abutment and permanent tooth can be attached in a variety of designs.
What is the Benefit?
• The long-term benefits of dental implants include improved appearance, comfort, speech and self-esteem.
• With the dental implant, the patient can eat more conveniently .
• embarrassment caused by removable partial and full dentures can be eliminated. In addition the implant is
• able to protect the remaining natural teeth, stop bone loss and restore facial skeletal structure
Overview of some availablecommercial short and mini implants
What is FEA?• Finite element analysis (FEA) is a
computerized method for predicting how a product reacts to real-world forces, vibration, heat, fluid flow, and other physical effects.
• Finite element analysis shows whether a product will break, wear out, or work the way it was designed. It is called analysis, but in the product development process, it is used to predict what is going to happen when the product is used.
What is ABAQUS?
• Abaqus FEA (formerly ABAQUS) is a software suite for finite element analysis and computer-aided engineering, originally released in 1978. The name and logo of this software are based on the abacus calculation tool. The Abaqus product suite consists of five core software products:
.• Abaqus/CAE, or "Complete Abaqus Environment" (a backronym with an obvious root in Computer-Aided Engineering). It is a software application used for both the modeling and analysis of mechanical components and assemblies (pre-processing) and visualizing the finite element analysis result. A subset of Abaqus/CAE including only the post-processing module can be launched independently in the Abaqus/Viewer product.
• Abaqus/Standard, a general-purpose Finite-Element analyzer that employs implicit integration scheme (traditional).
• Abaqus/Explicit, a special-purpose Finite-Element analyzer that employs explicit integration scheme to solve highly nonlinear systems with many complex contacts under transient loads.
• Abaqus/CFD, a Computational Fluid Dynamics software application which provides advanced computational fluid dynamics capabilities with extensive support for preprocessing and postprocessing provided in Abaqus/CAE.
• Abaqus/Electromagnetic, a Computational electromagnetics software application which solves advanced computational electromagnetic problems.
Samples
Human Body Parts
dental implant types
.
Osteoplant Dental Implant
Steps of Dental Implant Surgery
Missing molar in the mandible, to be treated with a dental implant-supported restoration
.
After flap elevation, the cortical bone is visible
Dental implant with an abutment to be placed in the ridge created by the missing molar
Implant is placed in the ridge
Occlusal view of the implant after 2 months of healing
Abutment is prepared and attached to the implant
Porcelain-fused metal implant-supported restoration in use with optimum treatment planning
Abaqus Analysis2D or 3D?
• The 3D model of the implant will contain >50000 dof.
• So we were supposed to use 2D model using axisymmetric solid CAXA model.
• But that facillity was not in Abaqus which we were using.
• So, we have used CAX4R.
Parts• PARTS
• A Abutment• S screw• CC Cortical
Bone• CB Cancellous
Bone.
Mechanism
• A dental implant resembles a screw constructed from titanium and is surgically placed into the bone to serve as the new root . Once the implant successfully fuses with the bone, an abutment is placed on top of the implant to serve as the platform that protrudes out of the gums, and the implant crown can then be seated on the abutment permanently
Cortical Bone
CoOrdinates(0,0)(0,5)(6.25,0)(7.5,0)(0,0)
Cancellous Bone
CoOrdinates(0,5) (0,10)(2.5,10)(2.5,15)(5,15)(6.25,15)(0,5)
Axisymmetricshell
ScrewCoOrdinates(0,10)(0,20)(2.5,20)(1.5,20)(1.5,10.1)(0,10.1)AxiSymmetricshell
AbutmentC0Ords(2.5,15)(2.5,2.5)(3.5,2.5)(5,20)(3.75,18.5)(3.75,15)(2.5,15)Axi SymmShell
Materials PropertyPART Young’s Modulus Poisson’s Ratio
Cortical Bone 13xE9 0.3
Cancelleous Bone 95x E8 0.25
Screw(Titanium) 105xE9 0.32
Abutment(Zirconium) 105xE9 0.3
What is Young’s modulus?
Poisson Ratio
Assembly
Interaction
I Interaction zoom
Step
Boundary Condition
Load
LoadName Vertical
Step Static General
Type Pressure
Region Vertical
Distribution Uniform
Magnitude 600
Name Horizontal
Step Static General
Type Pressure
Region Horizontal
Distribution Uniform
Magnitude 100
Mesh
0.3 0.2 0.1 0.05
MeshCentral Quad
Element Standard Linear
Family Axisymmetric Stress
Results 0.3 mess
Mesh size 0.2
Mesh 0.1
Mesh 0.05
Analysis• What is S Mises?• Von Mises stress• .Using this information an engineer can say his
design will fail, if the maximum value of Von Mises stress induced in the material is more than strength of the material.
• The concept of Von mises stress arises from the distortion energy failure theory.
.
S Max Principal
• Maximum Principle Stress Theory - According to this theory failure will occur when the maximum principal stress in a system reaches the value of the maximum stress at elastic limit in simple tension. This theory is approximately correct for cast iron and brittle materials generally.
Variation of position of S max & S mises with respect to mesh size
Mesh Size 0.3 0.2 0.1 0.05
S Max position
Medial lower corner of screw
Medial lower corner of screw
Medial lower corner of abutment
Lateral lower corner of screw
S Mises position
Lateral lower corner of screw
Lateral lower corner of screw
Lateral lower corner of screw
Lateral lower corner of screw
Variation of values of S max & S mises with respect to mesh size
Mesh Size 0.3 0.2 0.1 0.05
S Max value
+2.54xE2 +1.983xE2 +2.347xE2 +3.193xE2
S Mises Value
+1.721xE3 +2.11xE3 +2.336xE3 +2.938xE3
Conclusion • Considering the above s mises and max
principal value which have been plotted at the same site shows that maximum stress will occur lateral lower corner of screw and will lead to all related complication
• Though in comparison with the paper it says no serious stress fracture was found.
Complications: Broken Implant
Intraoral picture of a broken implant due to excessive loading after 1 year of use
Advantages of FEA study• FEA studies have several advantages over
clinical, pre-clinical, and in vitro studies. • Patients will not be harmed by the application
of new materials and treatment modalities that have not been previously tested.
• Animals will not suffer from these biomechanical studies.
Disadvantages of FEA study
• All of these applications are being performed on a computer, with critical limitations and assumptions that will clearly affect the applicability of the results to a real scenario.
• Simplifications are made for all simulated models; therefore, the models should be compared with each other within the same study.
Summary• FEA is a numerical stress analysis technique and is
extensively used in implant dentistry to evaluate the risk factors from a biomechanical point of view.
• Simplifications and assumptions are the limitations of FEA studies.
• Although advanced computer technology is used to obtain results from simulated models, many factors affecting clinical features such as implant macro and micro design, material properties, loading conditions, and boundary conditions are neglected or ignored. Therefore, correlating FEA results with preclinical and long-term clinical studies may help to validate research models
Acknowledgements
• Prof A.DEB , Associate Professor, Civil Engineering, IIT KGP
• Other members of Project Group• Stuff members of CAD Lab• IIT KGP free broadband service
.