Dental implant/ dentistry curriculum

OUTLINE
• The FEA of the 3.5 mm Bicon Implant-Abutment-
Bone system under central occlusal loads
• Mechanics of the Tapered Interference Fit in a 3.5
mm Bicon Implant
www.indiandentalacademy.com

WHAT IS A DENTAL IMPLANT?
 Dental implant is an artificial titanium fixture
(similar to those used in orthopedics)
which is placed surgically into the jaw bone to
substitute for a missing tooth and its root(s).

Surgical Procedure
STEP 1: INITIAL SURGERY
STEP 2: OSSEOINTEGRATION PERIOD
STEP 3: ABUTMENT CONNECTION
STEP 4: FINAL PROSTHETIC RESTORATION
Success Rates
lower jaw, front – 90 – 95%
lower jaw, back – 85 – 90%
upper jaw, front – 85 – 95%
upper jaw, back – 65 – 85%www.indiandentalacademy.com

History of Dental Implants
In 1952, Professor Per-Ingvar Branemark,
a Swedish surgeon, while conducting research
into the healing patterns of bone tissue,
accidentally discovered that when pure titanium
comes into direct contact with the living bone
tissue, the two literally grow together to form a
permanent biological adhesion. He named this
phenomenon "osseointegration".

First Implant Design by Branemark
INDIAN DENTAL ACADEMY
Leader in continuing dental education

ComparisonofImplantSystems
Astra Tech.
ITI
Bicon

The FEA of the 3.5 mm Bicon
Implant-Abutment-Bone system under
central occlusal loads
Assumptions:
• Analyses were linear, static and assumed that materials
were elastic, isotropic and homogenous.
• 100% osseointegration is assumed between bone and
implant. Bone and implant are assumed to be perfectly
bonded.
• The stresses in the bone due to the interference fit between
implant and abutment is assumed to be relaxed after the
insertion of the abutment.www.indiandentalacademy.com

Finite Element Model
 29117 Solid 45 Brick Elements (32000 limit)
 Symmetry boundary conditions on two cross-sections
and fixed in all dofs from the bottom of the bone.
V
H

RESULTS
 Effect of bone’s elastic modulus on the overall
stress distribution: Different finite element analyses
are run by varying bone mechanical properties
surrounding the implant. (1-16 GPa)
The properties of the bone depends on the location in
the jaw, the gender and age of the patient.

 Force: Vertical 100 N
 Bone Modulus: 16 GPa
 Force: Lateral 20 N

• Both the stress distribution and the stress levels
are effected significantly as the bone modulus is
varied.
• CT scan data may be a good source for obtaining
patient dependent implant designs.

 Maximum vertical and lateral load carrying capacity of
the bone:
The failure limit of the bone due to fatigue is 29 MPa.
[Evans et al.]
Lateral loads cause approximately 25 times higher
stresses in the bone than the vertical loads.www.indiandentalacademy.com

Mechanics of the Tapered Interference Fit
in a 3.5 mm Bicon Implant
 Perfectly elastic large displacement non-linear contact
finite element analysis for different insertion depths.
 Elastic-plastic large displacement non-linear contact
finite element analysis for different insertion depths.

 Different implant-abutment assemblies are performed
for 0.002”, 0.004”, 0.006”, 0.008” and 0.010” insertion
depths.
 Axisymmetric model is used.
 100% osseointegration is assumed between bone and
implant. Bone and implant are assumed to be perfectly
bonded.
 Bone is assumed to be elastic, isotropic and homogenous
with a Young’s modulus of 10 GPa.
Finite Element Model

Perfectly elastic large displacement non-linear
contact finite element analysis for different
insertion depths.
Perfectly Elastic Finite Element Results
0
50000
100000
150000
200000
250000
300000
350000
400000
450000
500000
0.47 0.49 0.51 0.53 0.55 0.57 0.59
Vertical Position
ContactPressure(P)psi
Interference depth: 0.002 in
 Contact pressure increases linearly with insertion
depth.

After 0.004” insertion depth, it is seen that plastic
deformation occurs in the implant.
An elastic-plastic model is needed.
Yield Strength of Ti-6Al-4V 139,236 Psiwww.indiandentalacademy.com

Elastic-plastic large displacement non-linear
contact finite element analysis for different
insertion depths
Stress
(MPA)
% Strain
Bilinear Isotropic Hardening Model

Contact Pressure Distribution for Different
Insertion Depths
Elastic-Plastic Finite Element Results
0
50000
100000
150000
200000
250000
300000
0.45 0.47 0.49 0.51 0.53 0.55 0.57 0.59
Vertical Position
ContactPressure(P)psi
 Contact pressure increases non-linearly with larger
insertion depths.

VonMisesStressDistributionintheImplant
Yield Strength of Ti-6Al-4V 139,236 Psi

VonMisesStressDistributionintheBone
Yield Strength of Bone 8,702 Psi

FUTURE WORK
 Comparison of different implant designs in
terms of stress distribution in the bone due to
occlusal loads.
 Modeling non-homogenous bone material
properties by incorporating with CT scan data.
 Comparison of different implant-abutment
interfaces

Dental implant/ dentistry curriculum

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