1. FINITE ELEMENT SIMULATION OF ND:YAG LASER
SHOCKPEENED NICKEL CHROME, COBALT CHROME
BASE METAL ALLOY FOR DENTAL APPLICATION
ILAVARASAN S 2010118017
KARTHIKEYAN S 2010118024
KUMAR K 2010118026
SARATH RAJA G 2010118040
Project Guide Dr. K Shanmuga Sundaram
Associate Professor
Department of Mechanical Engineering
College of Engineering, Guindy
Anna University, Chennai-25
2. Introduction
The main objective of this project is to give a solution to the
material selection for the dental implants or any other dental
treatments.
Dental Implants are become necessary now a days. Because,
• 69% of adults at an age of 35 to 44, lost at least one of their
permanent teeth by accident, gum disease or failed root canal.
• 26% of adults at an age of 74, have lost all their permanent teeth.
3. Objective
Selecting the suitable material,
laser for the dental application and
comparing the changes in the
mechanical properties after doing shock
peening operation
Hardness
Wear resistance
Yield strength
Ultimate strength
Modulus of Elasticity
The experimental results and the
theoretical results (simulation) are compared and
studied
4. Material Selection
Selection of Materials are based on the following things,
• Bio compatibility
• Color
• Life
• Durability
• Easy for shaping
• Aesthetics
• Physical properties
• Low thermal conductivity and expansion
• Resistance to wear and abrasion
• Resistance to chemical erosion
• Flexibility to adopt to a shape
• Strength to withstand the Mastication force
5. Material Selection Disadvantages
• Poor Strength
• High cost
• Low Wear resistance
• Less aesthetics
• Takes longer time to make
• Difficult to adjust
• Dull in tooth color
• May irritate the sensitive teeth (conducts cold)
• High cost
• Galvanic Shock
• More brittle
• Less life
• Chance for future cavities
• More time to place
o Gold Alloy
o Porcelain
o Plastic + Fine Glass
o Titanium
o Cobalt Chromium
o Nickel Chrome
7. Laser Shock Peening
Innovative surface enhancement process for
increasing resistance of the components.
This process creates compressive stress, four to
five times deeper than conventional shot peening
process.
This compressive surface stresses inhibit the
initiation and propagation of fatigue cracks.
The peening drives a high amplitude shock wave
into a material surface using high energy pulsed
laser.
Hence the purpose of this study is to compare
mechanical properties with microstructure of Nd-
YAG laser treated and non-treated on Ni-Cr and
Co-Cr
8. Nd: YAG Laser Shock peening
• 0.4 mm to 1 mm
• Low cost and easily available
• produce continuous laser at
room temperature
• portable systems
9. Parameter
Constant
Spot Diameter 1.2 mm
Pulse Duration 10 ms
Depth of Penetration 0.48 to 0.73 mm
Argon Shielding 45
0
Peening Speed 160 mm/s
No of Scan per Second 4
Variables
Pulse Energy Density 450 , 340 , 430 J/cm2
Pulse Frequency 1.1, 0.5, 2.5 kHz
Tensile Specimen using Pro/E
10. Finite Element Analysis
Structural – Static Analysis
Solid 185
Element Size 0.0001 (Fine Mesh)
Meshed view of Specimen
11. Displacement Vector Sum X Component Displacement
Y Component Displacement Z Component Displacement
15. Result
The Strain value of the Co-Cr Alloy got the smallest value than
the Ni-Cr Alloy.
So the less strain value material is opted for Dental applications.
Obviously Co-Cr alloy is better than Ni-Cr alloy.
Maximum Strain Value of Ni-Cr alloy : 657
Maximum Strain Value of Co-Cr alloy : 553
16. Result
Since the Co-Cr alloy is suitable for dental applications,
the Laser Parameter can be identified.
Pulse Energy Density value at max. strain value is 360×104J/m2
Pulse Energy Density value at min. strain value is 420×104 J/m2
So the least strain value is occurred during the Pulse
Energy Density value of 420 ×104 J/m2
17. Conclusion
Laser Shock Peening process is a trendsetter now a days in the
medical field. It’s low cost and accurate operations make it popular. So
that it gives an exact solution for all kind of age group who are all came
with a dental problem.
Nickel Chromium and Cobalt Chromium are some important
materials in dental implants. These materials can be used in dental
applications without doing shock peening process. But it cannot
withstand for a longer period. LSP improves the fatigue strength and
compressive stress of the material.
The aesthetics of Co-Cr is little lower than Ni-Cr. Otherwise Co-Cr
is the strongest material and can be shaped into any molar shape.
18. REFERENCES
[1] O Brian WJ. 2002 Dental Materials and their selection. Chicago
IL. Quintessence Publishing Co., Inc.; 2002.p.372-377
[2] Ding K, Ye L. Laser Shock peening performance and process
simulation. Cambridge: Woodhead Publishing; 2006
[3] Ballard P. Residual Stresses induced by rapid impact –
Application for laser shocking. Ecolo Polytechnique, April 1991
[4] Philips and Anusavic. Science of Dental Materials
