Tissue Management, Impression Making, Definitive Casts and Dies (Pt. II) Flashcards
Definitions
Solid Definitive Cast (or master or working
cast): replica of ____, ridge areas, and other parts of the ____
Die: positive reproduction of ____ tooth. Consists of a suitable hard substance of sufficient ____(usually improved stone, resin, or metal)
prepared teeth
dental arch
prepared
accuracy
Definitions
To learn to properly use virtual casts, the
underlying principles of conventional definitive cast and die systems must be understood
Virtual systems model the same information in
three dimensional formats that enable the technician to use virtual tools for certain phases of the restoration fabrication process
Virtual systems offer significantly improved ____.
efficiency
The accuracy of a cast and die is a function of the ____ of the impression.
The cast cannot contain ____ information than the impression from which it was made
completeness
more
Prerequisites of Definitive Cast
oMust exactly reproduce ____ tooth surfaces
oUnprepared teeth immediately adjacent to preparation must be free of ____
oSurfaces of teeth involved in ____ and occlusal surfaces of all unprepared teeth must allow for precise articulation
oAll relevant ____ should be reproduced
n including all ____ spaces and residual ridge contours involved in fixed prosthesis
prepared and unprepared voids anterior guidance soft tissues edentulous
Prerequisite of Die
oMust reproduce prepared tooth exactly oAll surfaces must be accurately duplicated n No bubbles or voids acceptable oUnprepared tooth structure immediately \_\_\_\_ to finish line should be easily discernible on die n Ideally \_\_\_\_ visible oAdequate access to margin imperative
cervical
0.5-1mm
Die Materials oDifferent materials n (1)\_\_\_\_ n(2)\_\_\_\_ (epoxy resin) n(3)\_\_\_\_ n(4)\_\_\_\_ materials psimilar to heavy body silicone or polyether impression materials
gypsum
resin
electroplated
flexible die
Die materials
ADA Type IV stone Advantages: \_\_\_\_ Straightforward technique \_\_\_\_ cost Straightforward in-office procedure Disadvantages: Will be \_\_\_\_ if not handled carefully (poor resistance to abrasion) Use: Most \_\_\_\_ Precautions: Accurate \_\_\_\_ essential Recommend vacuum mix
dimensional stability low damaged situations proportioning
Die materials
ADA Type V stone Advantages: \_\_\_\_ technique \_\_\_\_ cost Straightforward in-office procedure Harder than \_\_\_\_ Disadvantages: Increased \_\_\_\_ Use: Most \_\_\_\_ Precautions: Accurate \_\_\_\_ essential Recommend vacuum mix
straightforward low type IV expansion situations proportioning
Die materials
Expoxy Advantages: High \_\_\_\_ Good abrasion resistance Disadvantages: \_\_\_\_ \_\_\_\_-consuming complex procedure More \_\_\_\_ than stone Prostheses fit more \_\_\_\_ Use: \_\_\_\_ crowns Precautions: Not compatible with \_\_\_\_ or hydrocolloid
strength polymerization shrinkage time expensive tightly polysulfide
Die material
Electroplating Advantages: High \_\_\_\_ Good abrasion resistance Disadvantages: \_\_\_\_- consuming \_\_\_\_ equipment needed Use: \_\_\_\_ crowns Precautions: Silver entails use of \_\_\_\_, which is toxic Incompatible with many \_\_\_\_ materials
strength time special complete ceramic cyanide impression
Die Materials Selection Criteria oMust allow dimensionally \_\_\_\_ cast** oStrong and resistant to abrasion** oEasy to \_\_\_\_ and trim oCompatible with separating agent oReproduce \_\_\_\_ accurately oColor to contrast wax to visualize margin oEasily \_\_\_\_ by wax oCompatible with impression material
accurate
section
surface detail
wettable
Available Methods (1)Removable Dies
oDie is integral component of ____
n Can be lifted from cast for access
oPrecise ____ of die in definitive cast is crucial
n ____ or dowels
n Need resistance to rotation
o2 pours of ____ colors n First forms ____
n Second forms ____
definitive cast relocation brass pins contrasting teeth base
Available Methods (1)Removable Dies
o____ of dowels are critical
n If improperly placed, the dowels do not allow die of
prepared teeth to be withdrawn from the cast
oThis will be done in the preclinic
n Pindex
location and orientation
Available Methods
(1)Removable Dies
o Advantages
n Removable die
facilitates ____
n Cast pouring ____
o Disadvantages Extra \_\_\_\_ involved in making cast with dowels \_\_\_\_ equipment Care needed with dowel placement \_\_\_\_ difficult pGetting dies to seat p\_\_\_\_ die nDamage to interproximal margins
waxing and porcelain unimpeded steps special technically sawing
Available Methods
(2)Solid Cast with Individual Die
oMultiple pour technique
o____ than removable die
oMay be slightly more ____
oImpression poured in stone in area of preparation
n Trimmed to die with handle pSimilar to tooth root
oThen, second pour of the ____ made
simpler
accurate
entire arch
Available Methods
(2)Solid Cast with Individual Die
o____ started on die (first pour)
oTransferred to ____ to contour and anatomy
oReturned to die for ____
wax pattern
articulated cast
margins
Available Methods
(2)Solid Cast with Individual Die
o Advantages n Definitive cast requires \_\_\_\_ trimming n Gingival tissues intact can be used as a guide for \_\_\_\_ restoration n \_\_\_\_ procedure
o Disadvantages
n May be difficult to transfer wax pattern from ____
n Seating pattern on second pour more difficult due to second pour slightly ____ than first
n Only use with impression materials which could be poured more than once
pNot ____ hydrocolloid
minimum contouring straightforward cast to die larger reversible
Available Methods (3)Alternative Die Systems
oAccu-Trac technique. Di-Lok n Many other systems available n Utilizes a precision tray with a \_\_\_\_ n Impression is poured and seated on the \_\_\_\_ n Following setting, the tray is \_\_\_\_ and stone cast removed n Dies are sectioned n Cast and die reassembled and mounted on \_\_\_\_
magnetic indexer
tray
disassembled
articulator
Accu-trac technique
tables!
ya
Available methods
Alternative die systems
o Advantages
n ____ die
n Cast pouring unimpeded
n Less ____ than pindex
o Disadvantages n \_\_\_\_ n Care needed during reassembly n \_\_\_\_ equipment needed n Care needed when pouring to get proper orientation
removable
costly
bulky
special
Available Methods
Choice of Die Systems
oDepends upon
n____ preference
nDental technician preference
nAssessment of ____
If used properly, all available systems achieve clinically acceptable ____
operator
advantages/disadvantages
accuracy
Pindex Model Overview
Refer to video and laboratory manual for specific information
oPour final impression oWait for stone to set
n ____minutes
oSeparate impression
oTrim excess stone with cast trimmer
n Base thickness ____ inch
n Integral router and sandpaper point to trim lingual
oUse pindex to drill holes
40
3/4 - 1
Pindex Model Overview
Refer to video and laboratory manual for specific information
oPlace dowel pins into drilled holes with cyanoacrylate
oWait ____ minutes for cyanoacrylate to dry
oPlace sleeves on dowel pins
oApply separating medium
oPour base using pre-fabricated rubber mold and vacuum mix
5
Pindex Model Overview
Refer to video and laboratory manual for specific information
oLet base harden for ____ minutes oSeparate the rubber mold and trim
n ____mm land
oSeparate dies (#19 preclinically)
oTrim dies with acrylic bur oReturn dies to ____
oMount casts on articulator
n Preclinically, mount to previously mounted maxillary cast
30
3
master cast
