self healing dental composites shrinkage

1. 1
Dr. Dhyaa Kafagy
Mechanical & Bioengineering
George Mason University
Shrinkage Analysis of Microcapsules-Based
Dental Composite

2. Agenda
2
• Introduction of Dental Composite
• Research Approach
• Specimen Development
• Shrinkage Problem in Resins
• Conclusions
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

3. 3
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Human Tooth Anatomy
[Blausen gallery 2014]

4. Research Approach
4
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Synthesis of Dental
Composite & Microcapsules
Specimen Development
Quasi-Static & Fatigue
Characterization
Shrinkage Analysis
Self-Healing
Dental
Composite

5. 5
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Restoratives
[6]
Bacteria turn sugar to acid

6. Dental Restoratives
6
Amalgam filling
1830
Resin-based dental
composites filling
1990-2000
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

7. Dental Composite
7
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Barium Glass Dental Filler
Bis-GMA: Bisphenol A di-glycidyl methacrylate
UDMA: Urethane di-methacrylate

8. Typical Dental Composite Monomers
8
Barium Glass Dental FillerIntroduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Methacrylate monomers
binds filler particles
together

9. Photo Initiator Camphorquinone (CQ)
9
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Photo Initiators (CQ)
Chemical Initiators
Photo-Chemical Initiators

10. Inorganic Filler
10
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Barium Silicate glass is an inorganic filler
Increase modulus elasticity
Reduces shrinkage and
water absorption

11. 11
Restorations Cracks & Failure
Restoration Failure
PH changes
& Humidity
Thermal
Stresses
Cracks
2.5 KN
Mastication
load
Restoration
Failure
Additional dental
procedures & cost
2-7 %
Shrinkage
Stress
Restoration Failure
Occlusion &
articulation

12. Occlusion Stresses
12
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
[2],[3]

13. Shrinkage Stresses
13
[1]
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Shrinkage Stresses Cracks Failure
To date, no
methacrylate-based
composite has solved
the shrinkage problem.

14. 14
Failure of Dental Composite
Replacement of failed dental composite restorative [6]
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

15. 15
Adhesive and shrinkage
forces work in strong
opposition - lead to failure
Marginal integrity increased due
to reduced shrinkage forces

16. Specimen Fabrication
16
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

17. Volume Per Gallon Cups
17
Measuring Volume by Water Displacement Method

18. Synthesis of Microcapsules
18
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
30 µm -50 µm Microcapsules

19. Self-Healing Mechanism
19
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

20. Lab-Made Dental Composite
20
Dental Composite + 5 wt% of microcapsules
Component (wt%)
Microcapsules 5
Filler 55
Bis-GMA 19.01
UDMA 19.01
TMPTMA 1.9
Photo Initiator (CQ) 0.08
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Methacrylate
Monomers
60% Total
Tertiary Amine was removed

21. Microcapsules Healing System
21
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Bis-GMA
UDMA
TMPET
+
PA
+
Tertiary Amine
+
Dye Fluorescent
BPO
+
PA
Resin Microcapsule BPO Microcapsule
MBDMA: The tertiary amine ctivator,4 ,4’-methylene bis (N,N-dimethylaniline)
TMPET: Trimethylolpropane Ethoxylate Triacrylate

22. Microcapsules
22
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Optical SEM
Resin
BPO
BPO
Resin

23. SEM Microcapsule Toughening
23
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Dental composite
with 15% microcapsules
Pure dental composite

24. 25
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Lab-made vs. CHARISMA Commercial D.C
Impact of Dental Filler
CHARISMA
dental
Composite
The Impact of
removing
filler

25. 26
Shrinkage Analysis Results
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions

26. Conclusions – Shrinkage Analysis
27
Introduction
Research
Approach
Specimen Quasi-Static Fatigue Conclusions
Addition of 5% - 30% MC reduces the volume
shrinkage from 2% - 1%.

27. Questions
28