Sdm presentation

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


NOBILITY IN THOUGHTS
BELIEF IN ACTION
AIMED IN THE RIGHT DIRECTION


INTRODUCTION TO THE FINITE ELEMENT
METHOD

---- DR. CHETAN JAYADE
ASST. PROF.
DEPARTMENT OF ORTHODONTICS
S.D.M. DENTAL COLLEGE


My involvement with FEM

FEM Course at B.V.B, Hubli
FEM Course at MSRSAS, Bangalore


Why the need for orthodontists to know about
FEM?
An increase in the scope for research
A need for basic understanding about the engineering
areas of application.


SCOPE OF THE TALK
•An overview of FEA and it’s increasing role in
research
• To understand the capabilities and the limitations
• The role of a clinician in a research study involving
FEA
•Studies in various branches of Medicine and
dentistry involving FEA

SCOPE OF THE TALK
•Usage of FEA in Orthodontics
•Sources of understanding FEA
•An introduction to Rapid Prototyping
•Uses of Rapid Prototyping in Dentistry


BIOMEDICAL ENGINEERING
An amalgamation of the medical and engineering
specialties
-- The human genome project
-- CAD/
CAM and other computerised
application areas


BIOMEDICAL ENGINEER
ING

Basic Research
Combination


Clinical

BASIC RESEARCH
Experimental
Numerical

Analytical

---FEA
---NON-FEA


W
HAT IS FEA?
It is a means of discretizing a continuous structure
into sub-domains called Finite Elements.


W
HAT IS FEA?
Essentially an attempt at simulating a physical
object and analysing

it’s behaviour

subjected to various circumstances


when

W FEA?
HY
• Accuracy
•R
eproducibility
• No usage of materials
• Generation of intra-material results


FINITE ELEMENT ANALYSIS(FEA)
Termed by Clough in 1960
Gained popularity in the civil and the Aerospace
industry


First introduced to the dental arena in the 1970’s
Growth model documented by MOSS in 1980.


Current upsurge in interest due to
a)Potential of applicability
b)Desktop management


Basic steps--a)Pre-processing
b)Processing
c)Post-processing


Pre-Processing basically involves modelling of the
structure being studied.
Probably the most crucial step.


Pre-Processing --- Newer possibilities of modelling
of complex structures
a)3-D CT scanning
b)3-D Laser scanner
c)Voxel modelling

In Pre-processing, the structure being studied is
discretised into smaller units termed the
elements.
Each element is free to get displaced in all the
three planes of space.


The element co-ordinates (x,y,z) can be either
a) Global Co-ordinate system or
b) The Local Co-ordinate system


Various categories of elements exist.
Examples are
--- Shell element
---Beam element
---Truss element etc.


EXAMPLES OF ELEMENTS


These elements are connected at certain points termed
‘Nodes’.
The joining of elements into nodes and eliminating
duplicate nodes is termed as “Meshing”


The mesh size is a crucial determinant of the accuracy
of the result.
However, it is inversely related to the time involved in
the analysis.


The meshed model is now a free floating body. To
simulate the exact structure, the material
properties are assigned and boundary conditions
enforced.


Material properties : The minimum properties to be
assigned are a) The Modulus of elasticity and
b)Poisson’s ratio.


Material properties : Modulus of elasticity(Young’s
modulus)refers to the stiffness of the material
within it’s elastic range.
E =

Stress
Strain


Modulus of elasticity of dental structures are :
a) Enamel --- 65 GPa
b) Dentin -- 15 GPa
c) Alveolar bone – 10 GPa
d) Periodontal ligament – 0.05 GPa


Material properties : Poisson’s ratio denotes the strain
imposed on the material relative to the axis of the
load applied.
P =

Strain perp. to the force
-----------------------------------Strain parallel to the force


Poisson’s ratio for dental structures are:
a) Enamel --

0.32

b) Dentin --

0.28

c) Alveolar bone –- 0.33
d) Periodontal ligament-- 0.3


FINITE ELEMENT ANALYSIS (FEA)
After assigning the material properties, the material is
constrained identical to the real situation.
The freedom of the body to be displaced is termed as
the “degrees of freedom”.
Each element has six degrees of freedom.


FINITE ELEMENT ANALYSIS (FEA)
The final step in Pre-processing is the application of
loads. These can be either force or moments and be
directed at any node in all the three planes of
space.


W
hat

Does

The

Computer Do

Processing?
a) Solving of differential equations.
b) Assemblage into matrices
c) Summation of the matrix equations

During

The

The equation for the simplest linear static analysis is
represented as :
[F] = {K} {u}
The non-linear analysis is solved usually by what is
termed as the “Newton-R
aphson method”

Post-Processing -a) Graphical output
b) Numerical output
c) Animated output


ROLE OF A MEDICAL OR A DENTAL
PROFESSIONAL DUR
ING A RESEAR W
CH ORK
INVOLVING FEA
•

Planning a feasible study

•

Software to be used

•

Type of Model – 2-D or 3-D

•

Type of analysis

ROLE OF A MEDICAL OR A DENTAL
PROFESSIONAL DUR
ING A RESEAR W
CH ORK
INVOLVING FEA
Software to be used
•

Accuracy

•

Analysis modules

•

Mainframe capabilities

AREAS OF APPLICATIONS

BIOMECHANICAL

MECHANICAL

Orthodontics
Prosthodontics
Oral Surgery
Periodontics

ORTHODONTIC USAGE
Alternative to cephalometry
Growth assessment
Stress pattern generation


ORTHODONTIC USAGE
•

Limitations of conventional cephalometry in
establishing the exact areas of growth .

•

Advantages of FEM in Growth studies


ORTHODONTIC USAGE
•

Melvin Moss used the concept of Growth
tensors.

•

Tensors, although being abstract entities, are
able

to

pinpoint

the

extensions(strains)

local

growth

CONCEPT OF GROWTH TENSORS


ORTHODONTIC USAGE
Stress pattern generation --Nasomaxillary region
Mandible and condyle
Dento-alveolar
Attachments and other materials


ORTHODONTIC USAGE
Stress pattern generation --Nasomaxillary region


MODELLING OF THE MANDIBLE


ANALYSIS OF THE MANDIBLE


MODELLING OF HUMAN TEETH


LOSS OF ATTACHMENT AND IT’S RELATION TO
THE M/F RATIOS


RELEVANCE OF USING TPA AS A SOURCE OF
ANCHORAGE


MODELLING OF ORTHODONTIC
BRACKETS


ANALYSIS OF STRESSES IN ORTHODONTIC
BRACKETS


ANALYSIS OF STRESSES IN ORTHODONTIC
BRACKETS AND ADHESIVES


F

R

A MODELLED STANDARD LOOP

DISPLACED SHAPE OF THE LOOP

T Loop and L loop with angulated legs


A NEW FINDING


PR
OSTHODONTIC USAGE
Stress pattern generation --Edentulous jaws
Complete dentures
Over-dentures
Crowns and Fixed partial dentures
Implants

STRESS ANALYSIS OF A CAST
RESTORATION


MODELLING OF AN IMPLANT IN THE
MANDIBLE


ANALYSIS OF THE IMPLANT


OR AND MAXILLOFACIAL SURGERY
AL
Surgical stresses generated
Stresses in the TMJ
Distraction osteogenesis stresses


MODELLING OF THE HUMAN TMJ


THE MODELLED TMJ


ANALYSIS OF THE TMJ- NORMAL MOVEMENTS


ANALYSIS OF THE TMJ - ENFORCED MOVEMENTS


PERIODONTICS
Stresses in the periodontium
Changes due to loss of bone support
Designing of oral resonators


ANALYSIS OF RESONATORS


USES OF FEA IN PALEONTOLOGY
-- A MODELLED DINOSAUR CRANIUM


SOURCES OF DATA
INTERNET –

www.femur.wpi.edu
www.anamedic.com
www.feainfo.com

TEXTS : -

Chandrupatla et.al
Lakshminarayan H.V
Champion Jr.


RAPID PROTOTYPING
This refers to the process of production of
any physical object scanned via special devices.


RAPID PROTOTYPING
USES:
a) Instrument designing
b) Maxillofacial surgery
c) Implantology


RAPID PROTOTYPING
Output generation
a) 3-D printing
b) Stereolithography
c) Vacuum casting
Facility of Rapid Prototyping available at the
IISC, Bangalore

USES OF RAPID PROTOTYPING
--CRANIOFACIAL DEFECTS


USES OF RAPID PROTOTYPING


APPLICATIONS OF RAPID PROTOTYPING


CONCLUSION
The interaction of Dental and Engineering fields
is at a new helm; we have tried to initiate a
fruitful togetherness.


THANK YOU


Sdm presentation

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (6)

En vedette

En vedette (17)

Similaire à Sdm presentation

Similaire à Sdm presentation (20)

Plus de Indian dental academy

Plus de Indian dental academy (20)

Sdm presentation