1. D. Kafagy, S. Khajotia, and M. Keller
The University of Tulsa
Department of Mechanical Engineering
Oklahoma University
School Of Dentistry

2. Introduction
2
Blausen gallery 2014
Sectional
Anatomy of
Human Teeth
1st Molar

3. Outline
3
Motivation & Significance
Research Aims
Research Approach
Experimental & FEA Methods
Results
Conclusions

4. Research Aims
Synthesis self-healing dental
resin composites
Characterization of self-healing
dental composites using quasi-
static and fatigue tests
Development and validation a
new testing specimen
4

5. Motivation and Significance
5
Amalgam filling
1830
Resin based dental
composites filling
1990-2000
Synthetic resins used as
restorative or adhesives

6. Motivation and Significance
6
Restoration Failure
Thermal
Stresses
Hot/Cold
PH changes
& Humidity
Crack initiation
& Propagation
(5-2500) N
Chewing
Cyclic load
Restoration Failure
Additional dental procedures & cost

7. Dental Composites
Dental resin composites
Polymer matrix : Bis-GMA, & other
Monomers
Reinforcement: Filler material (silica)
A photo initiator
50-80%
Reinforcement
Matrix
7

8. Self-Healing Technology using microcapsules
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Self-Healing in resin based
dental composites
Physical
Energy
Chemical
Response
Physical
Response
8

9. Making of healing microcapsules
Microcapsules
Diameter range
(50-60) µm
9
Activator (resin)
Initiator (BPO)
Emulsion
Process
9

10. Experimental & FEA
Finite element analysis (FEA)
Dental resin composites
Miniatures of tapered doubled
cantilever beam (TDCB)
Quasi-static & fatigue tests
Healing microcapsules
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11. Why cTDCB Specimens
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 cTDCB specimen has independent crack length
 As the crack propagate the specimen width getting wider
 dc/da = constant
Experimental testing of the
compliances at several crack
lengths of the cTDCB

12. FEA of the cTDCB
12

13. Quasi-Static Test of Dental Composites Specimens
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Load frame and specimens grips
Tensile load were applied to the specimens
LabVIEW virtual program was used to control the test

14. Types of Self-healing Specimens (Tested)
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Pure dental composites
Injected healed- of pure dental composites
Virgin in-situ dental composites with 5% microcapsules
Healed in-situ dental composites with 5%
microcapsules

15. Control specimen healing (injection)
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Pure dental composites (No microcapsules)
Injected with healing components in fluid form (activator &
initiator)
The injected specimens were kept under water for 24 hours
The healed specimens were tested again

16. In-situ specimen (self-healing)
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Dental composites with microcapsules
Healing components in (activator & initiator)
microcapsules
The in-situ specimens were kept under water for 24 hours
The self-healed specimens were tested again

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70
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Virgin pure dental composite
Injected healed
Virgin in-situ
Healed in-situ
Displacement (mm)
Load(N)
Results of the Quasi-Static Test

18. Conclusions
cTDCB specimens suitable for our research because of the crack length independency
and low cost.
The addition of 5 wt% microcapsules to the dental composite served to increase the
virgin toughness by 40%.
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19. Conclusions
The in-situ self-healing of a dental composite using microcapsules was successfully
demonstrated
The measured healing efficiency in the in-situ self-healing specimens were in range of
10.31% to 36.62%.
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20. Future Work
Fatigue test of resin dental composite using healing control and in-situ.
Optimization of size and percentage of self-healing microcapsules with dental
composites.
Characterization of self-healing dental material under various clinical conditions
FEA of self-healing dental composites and molar teeth
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21. Acknowledgment
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