Johnston: Provisional Restorative Resin Materials Flashcards
Ideal Properties for Provisional Restorative Materials:
- ______ of Formation
- Promotes ____ ______
- ________ Appearance
- Stable and ________
- Ease
- Oral Health
- Esthetic
- Durable
A Resin-based restorative material (filled polymer) is formed by the combination of ______ + ______+ _______.
Monomer
Filler
Active Initiator
What is “translucency Parameter” or how is it determined/measured?
Comparing the color difference of material when it is held up to a black backing vs when held up to a white backing.
A positive quality of resin-based restorative materials is that they are _____ and _____ insulating.
Thermally
Electrically
A disadvantage of resin-based restorative materials is the _______ reaction during polymerization.
Exothermic
There is a ______ coefficient of thermal expansion on heating and a polymerization _______ during cooling associated with resin-based restorative materials.
High
Shrinkage
Do resin-based restorative materials have a high or low toughness?
Low
For ideal restorative materials, there must be a balance between which three properties?
Physical, Chemical, and Biological
What is the difference between thermoplastic and thermoset polymers?
Thermoplastic: NO CROSS-LINKING, the physical state is REVERSIBLY controlled by temperature (i.e: Wax)
Thermoset: IRREVERSIBLE CROSS-LINKING occurs during transformation from monomer to polymer
What is the difference between a polymer and a co-polymer?
Polymer: Formed from many monomers (same kind)
Co-Polymer: Formed from many monomers (of at least two types of monomer)
What is a monomer?
A molecule capable of covalent bonding with another monomer.
What is the difference between addition and condensation polymerization?
Addition: No By-products (free radical, ring opening, ionic)
Condensation: Results in a by-product
Most current dental restorative resins are formed by which mechanism of polymerization?
Free-Radical polymerization (type of Addition)
During free-radical polymerization, there is a change from liquid/paste into a solid that results in the _______ of advantageous final properties.
Increase
True or False: A negative aspect of free-radical polymerization is that it causes the material to heat up.
True
During free-radical polymerization, the density ______ and causes a volumetric __________ that can be offset if porosity is created.
Increases
Contraction
What are the chemical stages of Polymerization?
- Activation of the initiator
- Activation of the monomer
- Polymer growth
- Termination
By what three methods can the initiator be activated?
Heat, Light, or Chemical
Which method of initiator activation is the most efficient?
Heat:
- it is uniform
- gives a large working time
What are three disadvantages of heat activation?
- Requires mixing of initiator and monomer
- Requires heat equipment
- Excessive heat causes porosity
Which two methods for activating the initiator require that chemical activator and monomer be mixed?
Heat and Chemical Require mixing
light activation material is pre-mixed by manufacturer
In ______ activation, the working time is fixed by the ingredients.
Chemical
In ______ activation, the working time is practically infinite.
Light
In _______ activation, the ingredients can be mixed by the manufacturer.
Light
An active monomer is formed by the reaction of _______ with monomer.
Free Radical
During activation of the monomer, what does the free radical do?
The free radical changes a double bond to two single bonds (release of heat).
During activation of the monomer, what does the free radical do?
The free radical changes a double bond to two single bonds (release of heat).
An active monomer will _______ combine with more monomer.
spontaneously
During growth of the polymer, what happens to the density of the material?
Density increases
Monomers with __________ cause cross-linking between two growing polymers.
Dual-Functionality
What is Dual-Functionality?
There are two sets of double bonds in a monomer that are attaching to and cross-linking TWO growing polymers
Bis-acrylates, Urethane dimethacrylate, and ethylene glycol dimethacrylate are all dental resins that utilize ____ _____ during polymerization.
Dual Functionality
The greater the size of methacrylate monomer (methyl vs ethyl), the ______ the polymerization shrinkage.
Less
The greater the size of methacrylate monomer, the ____ the heat of reaction.
Less
The greater the size of methacrylate monomer, the ______ the mechanical properties of the set resin.
Lower
A greater size methacrylate monomer is beneficial because of less ___1___ and __2__, but is negatively effected by the decreased __3__.
- Less Polymerization shrinkage
- Less Heat of reaction
- Decreased mechanical properties of the set
What are the physical state changes during growth of the active polymer?
- Liquid (sandy)
- String Formation
- Dough Stage (plastic)
- Rubber Stage (elastic)
- Solid
When the active polymerization process goes from the ____ stage to the _____ stage, you can no longer deform the material without permanent changes.
Dough (plastic)
Rubber (elastic)
What are the three mechanisms for termination of the actively growing polymer?
- Combine two active polymers
- Transfer of Free Radical stops a growing polymer while also activating a single monomer
- Contaminants
What are four commonly encountered contaminants in dental polymerization?
- Oxygen
- Sulfur
- Eugenol
- Hydroquinone
True or False: Termination of a growing polymer due to contamination will always result in a lack of setting.
False: There may be “no setting” or there could be a “reduction in advantageous property development”
Residual free monomer is not _______.
Biocompatible
Concerning the composition of dental resins, the monomer and activation system becomes the _______.
Polymer matrix
Filler particles will alter _____ properties.
Handling
Filler particles will reduce _______ _______.
Polymerization shrinkage
Filler particles will _______ the temperature increase of the setting polymer (density of heat of reaction).
Decrease
True or False: Filler particles will beneficially affect mechanical properties after setting.
True
True or False: Filler particles will beneficially affect mechanical properties after setting.
True
What are the two types of filler and the difference between the two?
Organic and Inorganic
Organic = SOLUBLE in monomer
Inorganic = requires silane bonding agent to bond to matrix BUT then provides better mechanical properties (wear, toughness, strength)
True or False: Inorganic fillers provide better mechanical properties.
True
*require silane bonding agent to bond to matrix
What are the goals for provisional materials regarding oral health?
Protect remaining tooth structure
Maintain periodontal health
Provide occlusal compatibility
Maintain tooth position
In order to be stable and durable, provisional materials must resist ______, _______, and _______.
Removal
Fracture
Discoloration
What are the four types of dental resins discussed?
PMMA
PR’MA
Bis-acrylate
Urethane DMA
What is PMMA? What is a good quality of this material?
Poly(methyl methacrylate) resin Fracture Toughness (ex. "Jet")
What is PR’MA? Give an example and a beneficial quality of this material?
Poly(ethyl or isobutyl methacrylate)
Less temperature rise during reaction (ex. “Trim”)
Which type of resin is most commonly used in dental materials and why?
Bis-acrylate (bis-GMA)
- Desirable Margin adaptation
- Less temperate rise during reaction
- Less toxic/allergenic
- Desirable odor
Which resin material has the least fracture toughness?
Trim (PR’MA)
What is an example of Urethane Dimethacrylate (DMA) and what are some desirable characteristics?
"Triad" -Fracture Toughness -Desirable Odor -Less toxic/allergenic (bad= high heat of reaction)
What is an example of Urethane Dimethacrylate (DMA) and what are some desirable characteristics?
"Triad" -Fracture Toughness -Desirable Odor -Less toxic/allergenic (bad= high heat of reaction)
When referring to fracture toughness, which is better: Triad or Trim?
Triad (Ureth.DMA) is more tough
Trim (PR’MA) is least tough
