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43 Cards in this Set
- Front
- Back
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1. What are some application of resin composite?
Six examples... |
1. Anterior direct restorations
2. Posterior direct restorations 3. Core build ups prior to crown 4. Indirect restorations 5. Pit and Fissure sealants 6. Resin-based cements |
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2. What are the composite types (by use)?
Six... |
1. Anterior
2. Posterior 3. Flowable 4. Packable (condensable) 5. Core build-up 6. Lab (indirect) |
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3. How many phases do composites have?
What are they in a composite resin? |
At least TWO distinct phases
1. Organic polymer matrix (continuous phase) 2. Inorganic particulate filler (dispersed phase) |
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4. What are the 3 components in dental resin composite?
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1. Resin matrix continuous phase
2. Inorganic filler dispersed phase 3. Coupling agent |
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5. What is O'brien's classification of resin composite?
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1. Fine particles: ground glass or quartz size
2. Microfilled: spherical colloidal silica 3. Hybrid: blend of 1 and 2 4. Microhybrid |
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6. What is sturdevants classification?
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A. Homogeneous or heterogeneous
(precured composite?) B. Hybrid (or not) C. Size |
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7. What is a homogeneous composite?
What is a heterogeneous composite? What is a hybrid? |
One primary particle size
Mixture of cured and uncured but one primary particle size Mixture of various particle sizes |
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8. What are characteristics of multipurpose composites?
What about nano composites? What about micro composites? |
High strength and modulus
High polish, strength, and modulus High polish and shrinkage |
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9. What are some properties of packable composites?
What about flowable? What about lab? |
Low shrinkage and wear
Low modulus and high wear Low wear and lab cost |
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10. What is the pyramid of properties of composites?
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Wear
Shrinkage Polishability Handling Properties |
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11. How do microfilled and microhybrid composites compare with....
1. Coef. thermal exp. 2. KHN 3. Polymerization shrink % 4. Polishability |
1. Microfilled is higher
2. Microhybrid is higher 3. Microfilled is higher 4. Microfilled has excellent |
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12. What are 4 characteristics of fine particles?
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1. Silica or glass filler particles
2. Unfilled polymer matrix 3. Silane coupling 4. 60-70% filled by volume, 70-90% by weigth |
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13. What is the size/shape of microfilled
How is there surface area-to-mass ratio? What does this do? How is the handling of microfilled improved? |
Spherical colloidal silica filler particles
High surface area-to-mass ratio Creates high viscosity and limits filler% Low viscosity resins added |
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14. What size particles are in hybrid?
How is their filler content? |
Two sizes of filler particles
**Colloidal silica + fine particles **Colloidal surrounds fine particles Higher filler content than microfilled |
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15. What particles are in microhybrids?
Why are they more "advance"? |
Microfilled and fine particles blends
1. Superior wear resistance 2. Good esthetics 3. Universal application |
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16. What is an oligomer?
What are thee oligomers in the polymer matrix? |
2-4 monomer units
Bis-GMA UDMA TEGMA |
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17. Why is the coupling agent silane used?
Three reasons... |
1. Strengthens composite
2. Limits crack propagation at interface 3. Reduces wear from particle loss |
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18. What are three ways in which the matrix is polymerized?
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1. Chemical (self) cure
2. Light cure 3. Dual cure |
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19. What are the 4 light curing?
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1. QTH
2. PAC 3. LED (light emitting diode) 4. LASER ("laser") |
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20. What is used in light cure?
Where is the absorption peak? |
Camphorquinone
474 nm |
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21. What is the energy output range?
What is the minimum? How could a heat rise affect the pulp? |
400-800 mW/cm^2
300 mW/cm^2 5-8 C heat rise can kill pulp cells |
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22. What is the C factor?
What does it measure? |
Configuration Factors
Ration of bound to unbound surfaces Measure shrinkage |
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23. What is the shrinkage of microfilled composites?
Fine particle? Microhybrid? |
2% - 4%
1% - 1.7% 1.5% - 1.7% |
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24. What are good techniques for composites?
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1. Layering to control shrinkage
2. Layering for esthetics 3. Use of air-inhibited layer 4. Re-curing final surface 5. Minimizing air voids |
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25. What are the important parts of the light cure?
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1. Light pipe
2. Light guard 3. Bandpass filters 4. Light and reflector 5. Cooling fan |
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26. What are three performance factors for light curing?
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1. Unit
-bulb, reflector, fiber bundle, voltage, barriers 2. Procedure -tip size, direction, distance, time, movement 3. Restoration -thickness, design, shade, filler, monomer |
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27. How much should you cure at a time?
What is the curing time for chemical? |
1.5 - 2 mm increments
3 - 5 minutes 25-45% unreacted at 24 hrs |
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28. What is curing time for light-initiated?
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75% complete at 10 minutes
Continues at least 24 hrs up to 30% unreacted at 24 hrs **cure depth is factor-dependent |
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29. What is the light-curing requirements?
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Typical resin composite 2 mm thick
Energy per Area 8J per square centimeter OR 400 mW/cm^2 for 20 seconds |
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30. What eye protection is there when light curing?
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1. Shield on light
2. Protective glasses 3. Hand-held filter |
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31. How is the thermal conductivity of resin matrix and inorganic filler?
Which composite expands more? |
Resin matrix
-low conductivity -high linear thermal expansion Inorganic filler -higher conductivity -lower linear thermal expansion Less filled microfilled composites expand more than hybrids or microhybrids |
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32. Do polymer matrix absorb water?
What does water absorption cause? Which composites absorb more water? |
Yes
Causes expansion but.... **this expansion is less than polymerization shrinkage Microfilled composites |
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33. What is a solvent of bis-GMA?
What is yellowing of composites due to? Why do light-cured systems have improved color stability? |
Alcohol
Due to tertiary amine accelerator breakdown in chemically cured systems Light-cured systems do not contain tertiary amine |
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34. How should the radiopacity of composites be?
What are added as filler particles to improve radiopacity? |
Should exceed radiopacity of enamel, but many do not
Less than that of dental amalgam Barium, strontium, zirconium |
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35. In what mechanical properties do hybrid composites beat microfilled int?
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Compressive strength
Tensile strength Young's modulus KHN |
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36. How do the mechanical properties compare to tooth structure?
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1. Highly filled composites approach compressive and tensile strength of dentin
2. Generally, composites have a Young's modulus much less than enamel |
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37. How do the mechanical properties of composites compare to tooth structure?
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3. Some highly filled composites approach the Young's modulus of dentin, but microfills are much less
4. KHN of composites much less than enamel but most are similar to dentin |
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38. What causes contact free wear?
Occlusal contact wear? Functional contact wear? |
Food
Centric tooth contact Eccentric movements |
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39. How do the following affect wear factors...
1. Increased filler volume 2. Decrease filler size 3. Softer filler particles 4. Use more anteriorly 5. Decreased air porosity |
1. (-)
2. (-) 3. (-) 4. (-) 5. (-) |
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40. How do the following affect wear factors...
6. Use light-cure, not chemical 7. Increase polymerization % 8. Use of silane coupling agent 9. Re-curing finished surface 10. Unfilled resin on finished surface |
6. (-)
7. (-) 8. (-) 9. (-) 10. (-) |
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41. What can cause post-operative sensitivity?
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1. Fluid microdynamics - percolation
2. Bacterial invasion from poor bond 3. Occlusal discrepancies 4. Cusp flexure |
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42. What is the placement technique for composites?
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1. Enamel and dentin bonding/sealing
2. Non-eugenol base in deep areas 3. Matrix and wedge application 4. Incremental fill and light cure 5. Maintain and work w/ air-inhibited layer 6. Occlusal/contour adjust, finish, polish 7. Post-finish etch, unfilled resin and cure |
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43. Is addition or repair possible with cured composites?
How is a porcelain one repaired? |
Yes
Hydrofluoric acid etch plus silane application |
