Biomaterials - Composite Flashcards
a physical mixture of 2 or more materials with superior properties as compared to the individual components.
Composite
________ uses:
- Tooth-colored restorative material
- Bonding agents (filler may be present)
- Sealants (filled)
- Composite resin luting agents (cement)
- Resin-modified glass ionomer material
Dental Composite Uses
Resin matrix phase reinforced by dispersed filler particle phase bound to the resin by a _____ coupling agent
silane
______:
◦Matrix in US products
Bis-GMA bisphenolA diglycidyl methacrylate
What is the filler particle in composite?
Crystalline silica
___;
◦Dispersed in resin matrix◦Distribution varies depending on the material
Filler
T/F: Matrix is not strong without fillers
True
1.Reinforcement of resin matrix:
◦Increase hardness, strength, elastic modulus, and wear resistance
2.DECREASED polymerization shrinkage: ~10% to ~2%
3.DECREASED thermal expansion and contraction
1. don’t expand or contract
4.Improved workability, handling
5.DECREASED water sorption
6.INCREASED radiopacity(Barium, Strontium, Zirconium)
Filler
◦Couples filler to resin matrix
◦Allows stress transfer from flexible matrix to higher modulus (aka less flexible) filler particle
◦Improves the mechanical properties
◦Decreased water sorption along filler-resin interface
Silane
What is the initiator for light-cured composite?
Camphoroquinone
What is the initiator for self-cured composite?
Benzoyl peroxide
- Prevent spontaneous polymerization when dispensed —-Stop polymerization from brief room light exposure (reacts with free radicals)
- Once the blue light is used, all inhibitor quickly consumed= polymerization chain reaction starts.
Polymerization Inhibitor
_____ are optical modifiers used to great more esthetic and whiter restorations
Opacifiers
What are the 3 different ways discussed that are used to classify composites?
Filler particle size and size distribution
Handling characteristics
Type of polymerization
\_\_\_\_\_ and \_\_\_ fill composite: Not used much today Large fillers ◦Rough surface finish Not good size distribution ◦Increased inter-filler resin space, low wear resistance Prone to staining
Macro and midifill
\_\_\_\_\_\_ fill composite: Excellent finish, Best wear resistance Weakest Use for esthetic, low-stress sites ◦Class III ◦Layer over hybrid, kit systems Brands: Durafill VS, Epic TMPT, Renamel, Heliomolar
Microfill
_____ filler composite
◦Mix of midi and microfillers, 1-10 & 0.01-0.1 m◦75-80 wt%◦Improved surface finish compared to macro and midi composites◦High strength◦Many of the of current materials are hybrid◦Z250, Z100, Herculite, TPH, APH, Point 4
Midi-micro Hyprid
_____ filler composite
a. Also called Microhybrids
b. Mix of mini and microfillers,0.1-1 and 0.01-0.1 m
c. 80-85 wt%
d. Newer material
1) Smoother finish than midi-micro hybrid
2) Slightly lower strengthe.ClearfilAPX, 4-Seasons, Miris, Vitalescence, Synergy, Tetric, EsthetX
Mini-micro Hybrid
_____ filler composite
◦Nanometer: 10-9Micrometer: 10-6
◦Mix of mini, and nanofillers,0.1-1 and 0.001-0.01 m (1-10 nm)
◦~80 wt%
◦Newest materials: FiltekSupreme Ultra (what is used in clinic), Premise, TPH3 (what you use in lab), Simile
◦Strength comparable to microhybrids and finish equivalent to microfills
◦Not all “nanocomposites” contain nanofiller(<100 nm), filler size reported in nm, i.e.300 nm
Mini-nano Hybrid
What are the 2 classifications based on handling characteristics?
Flowable
Packable
______ composite
Low viscosity hybrid
reduced filler,
40-60 wt%, adapts better without handling
Many are not radiopaque
◦Big problem= difficult to distinguish from recurrent caries
Flowable
