May 26, 2016 Flashcards
(93 cards)
What tray(s) do we use for taking the definiive impression?
custom fabricated tray or stock tray
We use this technique when making direct interim restorations:
ESF
3 techniques for making interim restorations:
direct, indirect, indirect-direct
indirect technique:
Make interim from impression in lab from cast, prep the cast as conservatively as possible (so we are making a temp based off of a different prep? conservative so we know we will have a little extra space that can be filled with PMMA through the whole
Indirect-direct technique:
Fabricate shell before preparation of the tooth out of PMMA using the diagnostic cast, line shell intraorally
Materials for direct restorations:
PMMA, autopolymerizing acrylic resin, others ( polycarbonate), autocured composite resin, bisacrylate,
Functions of interim
esthetics, establishes function, diagnostic tool to see if tx plann is effective for patient
Issue with improper restoration:
inflammed soft tissue, overgrowth over finish line, taking definitive impression not possible due to inflammation and bleeding
Liquid to powder ratio for PMMA:
3:1
PMMA
Plymethyl MethAcrylate PMMA
What type of reaction is taking place with PMMA?
addition polymerization
stages of PMMA polymerization:
sandy, stringy, doughy, rubbery, stiff
TF Monomer is highly volatile.
T
Composition of powder:
polymer (methyl methacrylate) , initiator (benzoyl peroxide), plasticizer, opacifier, and pigments
polymer for the material we are using:
mehyl methacrylates (beads or pearls)
initiator:
benzoyl peroxide
Pigments:
to give the required shades
Fxn of plasticizer:
alters the physical properties
TF? Heat is taken in during the process of polymerization.
F. given off, free radical creation, exothermic
Bisacrylate vs. PMMA:
Autocured composite resin: no taste/odor, virtually no shrinkage, very good fit, color stable, shorter setting time, good esthetics, stiffness (prone to chipping, esp with undercut)) higher cost, good strength, good wear resistance
TF We will have significant undercuts below the finish line.
T. Block with inlay wax
Types of direct technique materials
bisacrylate or PMMA (use PMMA this semester), ESP-clear matrix or ESF-Silicon, PMMA - easier to reline, less prone to fracture
Temp of bath water
120 degress
After applying wax below the finish line and in surrounding crevices:
apply lubricant to the prep and adjacent teeth, mix ortho resin and jet acrylic, 1:1