Restoration Materials (Composites) Flashcards
Properties of Silicate Cement 1878
- Restore _____ teeth
- Name composition
- Releases?
- Solubility? Roughness?
- Used to restore caries in anterior teeth
- Acid soluble glass & (phosphoric acid, buffering agent, water)
- Releases fluoride
- Very soluble & becomes rough quickly
Properties of Acrylic Resin 1930s
- Used as a an___ ____ on facial surfaces because of weakness
- Types of metal restorations involved with? Class ___& ___
- Used as esthetic veneer on facial surfaces bc weak
- Class II and Class IV metal restorations
Composition properties of Acrylic Resin
- Does polymerization shrinkage occur?
- Thermal expansion?
- Degree of wear resistance?
- Potential marginal leakage?
- Anyinjury to pulp?
- Recurrent caries prone?
- Does it change in color?
- High Polymerization Shrinkage
- High Coefficient of thermal expansion
- Lack of wear resistance
- Marginal Leakage
- Pulp Injury
- Recurrent caries
- Color Changes
Because _______ & ________ were not the best materials on their own, COMPOSITE was created
Silicate Cement & Acrylic Resin
Composition of Composite
1.
2.
- Polymer - resin matrix - BIS-GMA (Principal monomer)
- Inorganic Filler particles
By creating the new composite resin, two advantages were:
- Strength –?
- Thermal Expansion – ?
- Strength increased!
- Thermal Expansion Decreased!
How are different types of composite classified?
1.
2.
3.
FILLER
- size
- amount
- composition
Name the 2 types of monomers (form polymer) in composite resin
- BIS-GMA – main
- TEGDMA – added to reduce viscosity
How is polymerization of composite cured?
- Self-Cured
- Light Cured
In order for a composite to have light-curing capabilities, it must contain __________ (photo initiator)
Camphoroquinone
(Silicane Coupling Agent)
Why use an orange light cover to loupes light?
Composite will NOT polymerize under orange light (~600nm)
Composite will absorb light energy and polymerize when exposed to _____ nm
470 nm (Blue light)
The following are Curing _______ Factors
- Bulb frosting, Light reflector, Optical filter or degredation
- Fiberoptic bundle breakage
- Light-guide fracture
- Tip contamination by resin buildup
- Sterilization problems
- Infection control barriers
Curing Equipment Factors
The Following are __________ Factors
- Ligt tip direction
- Access to restoration
- Distance to surface
- Size of tip
- Tip Movement
- Time of exposure
Procedural Factors
The following are _______ Factors
- Restoration Thickness
- Cavity Design
- Filler amount and size
- Restoration Shade
- Monomer Ratios
Restoration Factors
Describe the shape of light polymerization? Where is the deepest spot of light penetration?
Cup Shape with rounded bottom. Center spot is where the deepest site of light penetration is at.
How far away should the light be away from the polymerizing composite material?
1-1.5mm
If the light is placed 1 - 1.5mm away from the composite, what it the depth of curing?
1.5 - 2.0 mm
Are curing lights hazardous to our eyes?
No
Higher powered lamps showed potential to cause damage at shorter distances viewing for 6 sec at 30-cm distance during an 8-hr workday
3 Classifications of composite based on handling characteristics
- Flowable
- Packable
- Univerasal
These are NOT condensable
3 Reasons why a bonding agent is required
- Linear coefficient of thermal expansion
- Modulus of Elasticity
- Polymerization Shrinkage
What does the “C-Factor” stand for?
of bondered surfaces// # of unbonded surfaces
If you have a high C factor….
bonded surfaces >>> # of unbonded surfaces
How to reduce internal stresses in a high C factor situation
- Should you use high intensity light?
- Bulk fill or incremental?
- Use of a liner?
- Soft-start polymerization instead of high intensity light
- Incremental addition of the material
- Use a stress breaking liner (filled dental adhesive, flowable composite, or RMGI)
2 Ways that gaps may form at the margins of composite restorations
- Polymerization Shrinkage
- Improper Insertion of the composite by the clinican
