Composite Resin and GIC Flashcards
composite resins are known as
FILLED RESINS
the most widely used restorative material
COMPOSITE RESIN
phases of composite resin (2)
- Continuous Polymeric Phase
- Discontinuous Inert Phase
the continuous polymeric phase of composite resin is due to the reaction between __________ and __________ resulting in ____________
glycidyl methacrylate + Bisphenol A = BisGMA
epoxide material in the continuous polymeric phase of CR
glycidyl methacrylate
organic material in the continuous polymeric phase of CR
Bisphenol A
discontinuous inert phase of CR is also known as
DISPERSED PHASE OF INERT FILLERS
inorganic fillers of composite resin (CR)
- quartz or silica
- lithium aluminum silicate
- various barium glasses
T or F: fillers increase the strength of the resin
TRUE
T or F: the coefficient of thermal expansion is increased due to inert fillers
FALSE. decreased (which is good = enhances use of resin)
filler surfaces are coated by
COUPLING AGENT
these increases strength of composite resin by coating the fillers
COUPLING AGENT
these decreases the solubility and water absorption of composite resin
COUPLING AGENT
coupling agents (2)
- VINYL SILANE
- EPOXY SILANE
basic types of CR
- CONVENTIONAL CR (MACROFILLED)
- MICROFILLED CR
- HYBRID CR or BLENDS
other types of CR
- FLOWABLE
- PACKABLE
this type of restoration provides a rough surface finish but has high compressive strength
CONVENTIONAL CR or MACROFILLED RESIN
the rough surface from macrofilled resin is due to the big size of what
FILLERS
filler size in macrofilled resin
5-25 microns (average of 8 microns)
amount of inorganic fillers in conventional CR
75-80%
amount of resin matrix in conventional CR
20-25%
this was designed to replace the rough surface finish of conventional CR
microfilled composite resin
amount of fillers in microfilled resin
inorganic: 35-50%
resin matrix: 50-65%
filler size in microfilled resin
0.01-0.004 microns
this type of CR has smooth surface finish but low compressive strength
microfilled CR
this type of CR has smooth surface finish and high compressive strength
hybrid CR or blends
amount of fillers in blends
inorganic: 70-80%
resin matrix: 20-30%
filler size of this type of CR is slightly smaller than the conventional and mixed with submicron-sized fillers
blends or hybrid CR
T or F: flowable composites has a rough surface making it prone to wearing
TRUE. flowable composites has low wear resistance = rough surface
T or F: the low compressive strength of flowable composites is due to lower filler content
TRUE
T or F: flowable composites are indicated for extensive Class I caries
FALSE. only small Class I and as a pit and fissure sealant
this type of CR is used as the first increment liner under a hybrid or packable composite
flowable composite
properties of flowable composite (4)
- easy to manipulate
- low wear resistance
- low filler content
- low compressive strength
indications of flowable composite (4)
- small Class I
- P and F sealant
- marginal repair material
- liner in hybrid and packable composites
this was designed to be more viscous and get a “feel” upon insertion similar to amalgam
PACKABLE COMPOSITE
goals of developing packable composite
- easier restoration of proximal contact
- similarity to handling properties of amalgam
indications of composite resin (5)
- Class I-VI restorations
- As foundation for core buildups
- Sealants and conservative restoration for preventive restorations
- Esthetic enhancement procedures
- Periodontal splinting
contraindications of composite resin (2)1
- stress-bearing posterior restorations
- when moisture control is poor
T or F: moisture control is attained through the use of rubber dam
TRUE
T or F: CR has a high thermal conductivity
FALSE. it is not metal !!! low thermal conductivity
advantages of CR (7)
- esthetic
- low thermal conductivity
- no galvanic reactions
- direct material (1 appointment only)
- easily repaired
- bonded resin may enhance tooth strength
- conservative preparation technique that minimizes removal of sound tooth structure
T or F: CR releases fluoride
FALSE. GIC releases fluoride but not CR
polymerization shrinkage of composite is resolved by
incremental packing
T or F: composite has good dentin adaptation
FALSE. that is why it needs to be etched and bonded
disadvantages of composite resin (7)
- no self-sealing quality like amalgam
- poor dentin marginal adaptation
- low wear resistance
- low fracture strength
- excessive wear under stress
- no fluoride release
- polymerization shrinkage may cause bacterial leakage and high stress to develop
methods of polymerization
- self cured
- light cured
method where polymerization is achieved by chemical means
self cured
activator and initiator in self cured polymerization
activator: tertiary amine
initiator: benzoyl peroxide
polymerization in light cured is achieved by
photochemical reaction
activator and initiator in light cured
activator: visible blue light
initiator: diketone compound (benzoin methyl ether)
T or F: light cured polymerization provides better resistance to wear and abrasion
TRUE
advantages of light cured polymerizaiton
- extended working time
- reduced porosities
- better resistance to wear and abrasion
procedures done in using composite resin
- remove fault from the tooth
- acid-etch
- bond
- add composite
acid etchant (37%) is usually applied for how long
15 seconds
appearance of cavity preparation after etching
chalky white or frosty
T or F: etchant should not be placed on soft tissue
TRUE. it is irritating to the pulp
how long is the bonding agent applied
10 seconds. then dried and cured for 10 seconds.
how long, usually, should composite be cured
20-30 seconds
this removes the surface smear layer oof dentin
acid etchant
what is the purpose of removing the surface smear layer of dentin
to enhance adaptation of the restorative material
T or F: acid etching improves wettability of polymer to enamel thus making the surface more reactive
TRUE
T or F: acid etching causes dissolution of exposed ends of the dentinal tubules to create surface irregularities
FALSE. enamel rods not dentinal tubules
surface irregularities made by acid etching increases _____ and provides ________
surface roughness; provides greater surface
objectives of acid etching (3)
- to remove surface smear layer of dentin
- to alter surface energy of freshly etched enamel to make surface more reactive
- to cause dissolution of exposed ends of enamel rods to crease surface irregularities
usual component of acid etchant
37% phosphoric acid
duration of acid etchant application based on percentage of acid
10% = 30 secs
20% = 20 secs
37% = 15 secs
used to ensure optimum bond betweeen teeth and composite
bonding agent
reaction of bonding agent with enamel
mechanical and chemical
reaction when bonding agent locks itself into the microporosities of enamel
mechanical
reaciton of bonding agent with the ions of tooth surface
chemical
common problems of composite restoration (7)
- poor isolation of operating area
- white line around enamel margin
- voids
- weak or missing proximal contacts
- incorrect shade
- poor retention
- contouring and finisihing problems
T or F: a solution to isolate area in deep-seated Class V and Class IV extensive caries is to use a matrix band
FALSE. use retraction cord for caries below gingiva
T or F: white line around the enamel margin may be due to too much etching and bonding in the area
FALSE. due to INADEQUATE etching and bonding
intense pressure applied during contouring may result in
white line around enamel margin
T or F: since the white line around enamel margin in seen only on the surface, removing and re-restoring the fault may solve the problem
TRUE
T or F: using a slow start polymerization technique will result in white line around enamel amrgin
FALSE. it will resolve the problem. white line around enamel margin is due to high intensity light curing
T or. F: marginal voids brought by self cure composite is repaired by preparing the area and re-restoring it
TRUE
T or F: shade seleciton must be done after the tooth is dried
FALSE. shade selection must be done before isolating the tooth
T or F: placing the shade of the selected tooth and curing it may be done to correctly choose the shade of the restoration
TRUE
what are some of the causes of weak and/or missing proximal contacts
- inadequately contoured matrix band
- inadequate weding
- movement of matrxi band during inseriton of composite
- matrix band too thick
- tacky composite pulling away from the matrix contact during insertion
T or F: a hand instrument mayb be used to hold the matrix band against the adjacent tooth while curing the composite
TRUE
T or F: bonding materials from different systems may be used
FALSE. this will cause poor retention of the material
these are water-based cements
GIC
properties of GIC (4)1
- bonds with enamel and dentin
- has anticariogenic propert
3, biocompatible with pulp (used as liner and base) - long term stability in oral environment
T or F: GIC is weaker than amalgam but stronger than composite
FALSE. both weaker than amalgam and composite
T or F: some materials of GIC has same radiographic appearance as caries
TRUE. some are radiolucent
advantages of GIC (5)
- inherent adhesion to tooth structure
- high retention rate
- little shrinkage and good marginal seal
- biocompatible
- minimal cavity prep required
disadvantages of GIC (6)
- brittle
- may crack
- radiolucent
- some release less fluoride than convetional GIC
- non-inherently radiopaque
- less esthetic than composite
T or F: due to its radiolucency, GIC is less esthetic than composite
TRUE
T or F: GIC may be used without bonding agent
TRUE. it has inherent adhesion to tooth strcuture
type of GIC used as luting cement
Type I
type of GIC used as liner and base
Type III
type of GIC used as resto material
Type II
classification of GIC
- Conventional Glass Ionomer
- Resin-Modified Glass Ionomer
- Polyacid-Modified Composite Resins (Compomers)
the new transulcent dental filling material
convetional glass ionomer
this type of GIC was introduced in 1972 and indicated for root surface caries
convetional glass ionomer
T or F: conventional glass ionomer may be used for full restorations
FALSE. it has low resistance and strength and should not be used as full resto
this type of GIC releses fluoride
convetional glass ionomer
type of GIC developed in 1992
resin-modified GI
resin modified GI is occasionally refereed to as
DUAL-CURE
this has generally much lower fluoride release than conventional GI due to addition of HEMA
resin-modified GI
this type of GIC is easier to use and possesses better strength, wear resistance, and esthetics than conventional GI
resin-modified GI
indications of RMGIs
- class V resto in adults who are high risk for caries
- Class I and II in primary teeth that won’t require long term service
this type is superior to RMGIs but inferior to composite
compomers/polyacid-modified CR
introduced in Europe in 1993 by McLean
compomers
this is composite with GIC components
COMPOMERS
T or F: compomers are light cured making them easy to manipulate
TRUE
T or F: like RMGIs, compomers release less fluoride
TRUE
GIC comes in
powder and liquid
powder component of GIC
aluminosilicate
liquid component of GIC
polyacrylic acid