6/2 - #19 Direct Jet Provisional, Adding Jet to Jet, 241-255, 256-259 Flashcards
provisionals are also called what
temporaries
what resins are used for provisional restorations
- polymethyl methacrylate (PMMA)
- polyethyl methacrylate (PEMA)
- polyvinylmethyl metharcylate (PVEMA)
- bis-acryl composite
- VLC urethane dimethacrylate
advantages of PMMA
- good fit
- good strength
- good polishability
- durability
advantages of PEMA
- good polishability
- minimal exothermic heat increase
- good stain resistance
- low shrinkage
advantages of PVEMA
- good polishability
- low exothermic heat increase
- good abrasion resistance
- good stain resistance
- flexibility
advantages of bis-acryl composite
- good marginal fit
- low exothermic heat increase
- good strength
- low shrinkage
advantages of VLC urethane dimethacrylate
- high surface hardness
- good strength
- good abrasion resistance
- controllable working time
- color stability
disadvantages of PMMA
- high exothermic heat increase
- low abrasion resistance
- free monomer toxic to pulp
- high volumetric shrinkage
disadvantages of PEMA
- surface hardness
- strength
- durability
- fracture toughness
disadvantages of PVEMA
- surface hardness
- strength
- esthetics
- fracture toughness
disadvantages of bis-acryl composite
- surface hardness
- less stain resistance
- limited shade selection
- limited polishability
- brittle
disadvantages of VLC urethane dimethacrylate
- marginal fit
- less stain resistance
- limited shade selection
- expensive
- brittle
examples of PMMA products? what is the most used?
Jet (most used)
Alike
Trim Plus
examples of PEMA
Snap
examples of PVEMA
Trim
what causes PVEMA to be more flexible
due to the vinyl present
examples of bis-acryl composite/bis-GMA composite
Luxatemp
Integrity
examples of VLC dimethacrylate
Triad
which resin features a high exothermic increase
PMMA
which resin is brittle
bis acryl and VLC urethane dimethacrylate
when making a provisional, do you place vaseline on both the manikin and live patients?
NO! only on manikin, but not on live patient
when combining the liquid monomer and powder, when will you place it into the matrix then into mouth?
when it is no longer sticky or glossy
how long does Jet take to set in typodont mouth? patient mouth?
manikin: 1:30-2:00 min
live patient: 1:00 min
basically just wit until it is hard and rubbery in dappen dish then can remove. don’t remove too early or too late
what should you do to the provisional to increase the speed of set
place in hot water bath
what handpiece and bur and rpm to use to clean provisional
straight handpiece
acrylic bur or use clean round rubber wheel at 6,000 rpm (can polish and take material off)
do you make the provisional first or the impression first?
PROVISIONAL FIRST!
should the shimstock hold with the provisional in but not when it’s out?
NO! should hold BOTH with and without the provisional in
should you remove centric or eccentric interferences?
remove ECCENTRIC (left, right, back forward)
keep centric (tap, tap)
can you add Jet to Jet
YES
just add liquid monomer to the area of the tooth you want to add to first
can you polish the provisional with wet pumice
YES. just stay away from margins
during the time between the preparation of the tooth and the placement of the definitive restoration, the tooth is protected by what?
provisional restoration
good provisional restoration should satisfy which requirements
- pulpal protection
- positional stability
- occlusal function
- ease of cleaning
- nonimpinging margins
- strength and retention
- esthetics
the restoration must be fabricated of a material that will prevent conduction of temperature extreme. The margin should be adapted well enough to prevent leakage of saliva
pulpal protection
the tooth should not be allowed to extrude or drift in any way. any movement will require adjustments of remake of definitive restoration at time of cementation
positional stability
being able function occlusally with provisional restoration will aid pt comfort, ward off tooth migration, and possibly prevent joint or neuromusclar imbalance
occlusal function
the restoration must be made of material and contour that will permit patient to keep it clean during time it is worn. if gingival tissues remain healthy while provisional crown is in place, there is less likelihood of a problem arising during cementation of definitive
ease of cleaning
the lack of ___ can result in inflammation, gingival proliferation, recession, or hemorrhage during the impression or cementation
nonimpinging margins
types of provisional restorations
- prefabricated vs. custom restorations
- direct vs. indirect techniques
examples of prefabricated provisionals
- stock aluminum cylinders
- anatomical metal crown forms
- clear celluloid cells
- tooth colored polycarbonate crown forms
what type of provisional restoration can be used only for single-tooth restorations
prefabricated provisionals
___ and ___ can be fabricated of several different kinds of resins by a variety of methods, direct or indirect
custom crowns; FPD
direct vs. indirect technique
direct: on the actual prepared teeth in the mouth
indirect: outside of the mouth on a cast made of quick-set plaster
which provisional technique is technique sensitive?
direct
which provisional technique is preferred for its accuracy since it doesnt have to be removed from tooth before it completely polymerizes
indirect
pure methyl methacrylate has a ___% volumetric shrinkage when it polymerizes
21%
a study showed that the marginal fit of PMMA provisional restoration could be improved by ___% by fabricating them indirectly
70%
which provisional technique is preferred for the protection that it provides to the pulp
indirect
what is the most superior resin?
no one resin is superior in all respects
which impression provides excellent stability
elastomeric
techniques for custom provisional restorations
- overimpression-fabricated provisional crown
- template fabricated provisional FPD
- template fabricated VLC provisional restoration
- shell-fabricated provisional restoration
- overimpression-fabricated bis-acryl composite crown
