May 26, 2016 Flashcards
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
TF Add powder to liquid when mixing the jet acrylic.
F. liquid to powder, drippy consistency
To what surface should we apply lubricant on the ESF-Clear matrix?
intalgio surface
Is lubricant needed with ESF-silicon?
no
During what stage should the mix be placed in the matix?
stringy stage
How to move the mix back into the prepared tooth area of the ESF-Silicon when it leaks into adjacent teeth:
mixing spatula
TF PMMA sticks to clear matrix.
T, this is why we apply lubricant
Purpose of adding the ESF-mix to the hot bath water for a FEW SECONDS:
to speed setting time and minimize amount of monomer
Where should you apply pressure when placing the ESF matrix on the prepared tooth area?
pressure on the djacent teeth, not the prepared tooth
Setting time for ESF-mix:
2-3 miniutes, lift ESF, but do not remove, replace ESF
Purpose of removing and replacing the interim while it is setting
to not lock in undercuts, both she’ll and interim are removed
To remove PMMA if if doesn’t come out with matrix
hemostat
Mark these protions of the interim restoration
Finish line and contact area
Where should you cut to remove the large excess?
from the side of the margin (with cone shaped e-cutter)
TF Cut vertically with the e-cutter.
F. will get short margin if you do
Use this e-cutter to trim margin:
H139UK e-cutter
FIrst practice:
remove tooth with the interim to see when you are in relation to the finish line and prevent overcuts
Pay attention to these contact for the interim:
proximal contacts, occlusion (centric and eccentric) appropriate margin adaptation
Use this to adjust occlusion:
e-cutter, extraorally, NOT high speed
Finish the interim restoration using:
the acrylic finishing bur, green cone
Coarsness of acrylic finishing bur, coarse to fine (colors):
dark green, gray, then light green
Keep your finger over this area when polishing with the lathe
margin. don’t polish the margin or it will be short
Luster the interim with:
the Robinson wheel (looks like oreo cooking from the side, rectangular)
To repair open contact with PMMA:
powder and liquid in 2 dapping dishes, liquid first, then powder, apply to interproximal area,(not below undercuts) place the interim intraorally and let set, place in hot water, then trim
How to repair margin:
lubricate typodont tooth, wet bennet brush, pick up PMMA and apply to the area you want to repair on the tooth, place interim restoration, remove when it starts getting warm, remove, set, polish
Always do this before placing automix tip:
bleed
TF Lifting and fitting back is important for the bisacrylic, ESF-INtegrity.
F. don’t do
Why is the ESF-Integrity (bisacrylic) more fragile, easily shipped than PMMA?
not as flexible as PMMA
Repairing ESF-Intergrity:
Sandblast the area to be repaired with A1203 particle, apply flowable composite, place interim on top, remove excess, cure, trim, finish, polish
Material for indirect-direct technique:
PMMA, duplicate diagnostic wax-up, prepared conservativey on cast, lubrican,t ESF PMMA on prepared cast, rubber band, set in hot water, remove shell, remove excess to ensure proper interproximal contacts, try in intraorally, adjust as needed, once seated create venting hole, mix PMMA material, place into shell, place on prepared tooth, finish, polish
Fabrication of external form
clear matrix or putty matrix
Aplly wax to buld up
compenstate for shrinkage of PMMA during soaking
Soak diagnostic cast here:
in slurry water
Tray to duplce
stock tray
Stone for duplicating cast:
microstone
The clear sheet should be placed here when using the biter guard heating/fabricating machine
footer area
How much should the clear material sag before we drop the footer over the cast?
1-1.5 cm, 1/2 inch
Trimming the cast after dropping the footer:
mark the matrix 5mm below the gingival line 1-2 teeth anterior and posterior
Cutting (bur?) he refers to that we don’t have:
Robinson bristle (bur?)
How to remove sharp areas of the clear platstic once removed from the cast:
scissors, green polishing cone
Fabrication of ESF:
silicon putty, 1 scoop
Should we place wax when using silicon putty on the diagnostic cast?
no
Cut back the putty to here:
leave 29, 30, and 31
Project today:
Tooth #15 CCC prep
Functional cusp for #15
lingual cusp
Non-Functional cusp for #15
buccal cusp
2 planes of reduction for buccal axial wall:
0.5-4mm above finisih line, second starts after that (not part of occlusal reduction) *Does this mean that we do not include this as part of the occlusal table when defining in CompareSoftwars?
Outlining the template:
outline to conver 2 or more teeth on either side of the prepared tooth or teeth
What machine do we use to make the custom trays?
Omnivac
What are we making when we lower the metal frame of the Omnivac?
the adaptation
How long should the heating unit remain in place to ensure completion of the the adatation?
10-15 seconds
How to remove the cast after using the Omnivac?
scissors and knife
How should the template be trimmed?
to cover 2 or more teeth on either side of what is prepped and about 3-5mm apical to the gingival margin of the prepped teeth
Consistency the material should be when adding to the clear tray for the interim:
barely flowable/ able to drip of stirring spatula
How long should we let the PMMA set after placing over prep and before lifting it out of its position the first time?
2-3 minutes
How long do we let the PMMA set in the hot water bath before and after setting on prep?
a few seconds
How to know how much to reduce the margins if they are too high on the restoration?
seat the interim, mark the high area with a sharpie to know exactly what to shave down’
2 other terms fro interim restoration:
temporary or provisional
What needs to be made for a custom crown?
ESF
What kind of amine is the activator in liquid?
tertiary
These combine in PMMA to form a free raidcal:
initiator with double bond in powder AND activator in liquid
TF PMMA absorbs color.
T
TF The ESF should be removed afte setting for about 2-3 minutes.
F. lifted, but not removed
Add this to your interim restoration before polishing on the lathe:
pumice and water
Common cause of short margin area:
using lathe and not keeping fingers over the margin to protect it
TF You can only polish vertically over the margin.
F. don’t polish the margin
Name of our PMMA:
Jet PMMA
When to soak the cast in slurry:
after placing wax (check)
TF We can use microbrush when applying the orthos resin.
F. bended brush only
Ortho resin is:
clear resin
