1. The document discusses various impression techniques for removable partial dentures, including the anatomic form impression using alginate or rubber base materials in a stock or custom tray.
2. It also covers the selective tissue placement or altered cast technique using materials like rubber, zinc oxide, or fluid wax at the framework stage.
3. Final impressions can be made with old or new dentures. The goals of impressions are to provide maximum support and equalize forces on teeth and bone.
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Impression Techniques for Removable Partial Dentures
1.
2.
3. Impression Techniques for
Removable Partial
Prosthesis
Dr. Amal Fathy KaddahDr. Amal Fathy Kaddah
Professor of Prosthodontic,Professor of Prosthodontic,
Faculty of Oral &DentalFaculty of Oral &Dental
Medicine, Cairo UniversityMedicine, Cairo University
4. Flow Chart of the RPD Clinical ProceduresFlow Chart of the RPD Clinical Procedures
DiagnosisDiagnosis and treatment planand treatment plan
Mouth preparation andMouth preparation and impressionimpression for the RPD frameworkfor the RPD framework
Seat and fit the RPD frameworkSeat and fit the RPD framework
Physiologic adjustment and altered cast impressionPhysiologic adjustment and altered cast impression
if it is extension base RPDif it is extension base RPD
Maxillomandibular registrationMaxillomandibular registration
(obtain face bow, VDO, and CR records)(obtain face bow, VDO, and CR records)
Tooth selectionTooth selection
Wax partial denture try-in if it is esthetic or complex caseWax partial denture try-in if it is esthetic or complex case
DeliveryDelivery
7. Types of impression techniques that can beTypes of impression techniques that can be
used in partial dentureused in partial denture construction:construction:
I- The anatomic form.I- The anatomic form.
II. The physiologic or the functional formII. The physiologic or the functional form..
2- At the framework stage:2- At the framework stage:
The selective tissue placement impression technique.The selective tissue placement impression technique.
(Altered cast technique)(Altered cast technique)
Final impressionsFinal impressions
3- At the finished denture stage:3- At the finished denture stage:
a- Old denture.a- Old denture.
b- New denture.b- New denture.
1- At the impression stage:1- At the impression stage:
- Mclean’s and Hindel’s Methods.
- One stage selected pressure impression technique..
The functional techniques using z o, rubberThe functional techniques using z o, rubber or fluid waxor fluid wax
8. ANATOMIC FORM
• The surface of the
residual ridge at rest.
• It is the shape of the
ridge before functional
load is applied.
FUNCTIONAL FORM
• It means the shape of the
residual ridge tissue when it is
functioning to support the
denture base.
• It is the shape of the ridge after
functional load is applied.
9. Goals of the ImpressionGoals of the Impression
TechniquesTechniques
Maximum coverage of the tissue available.Maximum coverage of the tissue available.
Provide maximum support, and so distribute load on as large areaProvide maximum support, and so distribute load on as large area
as possible (decrease force / unit area).as possible (decrease force / unit area).
• To distribute force widely.To distribute force widely.
Equalize support derived from edentulous ridges andEqualize support derived from edentulous ridges and
abutment teeth to decrease torque on teeth and preserveabutment teeth to decrease torque on teeth and preserve
bone.bone.
The base fit to the edentulous ridge.The base fit to the edentulous ridge.
Provide maximum support and retention.Provide maximum support and retention.
Direct forces to the primary stress bearing areas.Direct forces to the primary stress bearing areas.
Delineate accurately the peripheral extent of theDelineate accurately the peripheral extent of the
denture base.denture base.
10. To provideTo provide maximum supportmaximum support for thefor the
RPD.RPD.
Maintaining occlusal contactMaintaining occlusal contact to help into help in
distributing the occlusal forces overdistributing the occlusal forces over
the natural and artificial teeth.the natural and artificial teeth.
Minimizing movement of the baseMinimizing movement of the base thatthat
may create leverage on the abutmentmay create leverage on the abutment
teeth.teeth.
The main objective in anThe main objective in an
impression for distal extension is:impression for distal extension is:
11. Objectives of impression inObjectives of impression in
distal extensions:distal extensions:
OBTAIN MAXIMUMOBTAIN MAXIMUM
• SUPPORT
• RETENTION AND
• STABILITY
Critical landmarks:Critical landmarks: Retromolar pads,Retromolar pads,
hamular notch, vestibular depths andhamular notch, vestibular depths and
edentulous regionsedentulous regions
12. The Materials of Choice to Record aThe Materials of Choice to Record a
Partially Edentulous ArchPartially Edentulous Arch
Elastomeric impression materials:Elastomeric impression materials:
√√√√ Irreversible hydrocolloids (Alginate)Irreversible hydrocolloids (Alginate)
√√Rubber base impression materialsRubber base impression materials
√√Silicone impression materials (PVS)Silicone impression materials (PVS)
Polyether impression materialsPolyether impression materials
√√√√Irreversible hydrocolloids are the mostIrreversible hydrocolloids are the most
commonly used due tocommonly used due to the ease of handlingthe ease of handling,,
relatively low costrelatively low cost, and, and generating of dependable,generating of dependable,
accurate dental stone casts when properly manipulatedaccurate dental stone casts when properly manipulated
13. Types of impressionTypes of impression
materialmaterial
AlginateAlginate
Material of choice
Especially effective if there are lots
of soft tissue undercuts and/or
teeth with different axial alignments
Cross arch accuracy, surface
detail, hydrophillic properties are
great advantages
Cost effective and setting time is
ideal
More easily removed from the
stone cast than PVS or rubber base
14. Cost effective,
Hydrophyllic
Requires custom tray
Long setting time
May be difficult to
remove from the mouth
Difficult to remove from
the cast (can break
isolated teeth)
Types of impressionTypes of impression
materialmaterial
Polysulfide (Rubber
base)
15. Polyvinyl
siloxane
High cost, Hydrophobic
Custom tray is recommended
Due to impression rigidity may
be difficult to remove from a
mouth where the teeth have long
clinical crown lengths or with
different axial alignments.
Long setting time
Difficult to remove from the cast
(break thin or small isolated
Types of impressionTypes of impression
materialmaterial
16. Prior to the Final ImpressionPrior to the Final Impression
No plaque or calculusNo plaque or calculus
Healthy soft tissuesHealthy soft tissues
Initial therapyInitial therapy
completecomplete
18. Patient PreparationPatient Preparation
Instructions to patient
Relax lips, tongue, and cheeks
Advise patient that you will ask them to
lift their tongue
Ask patient to concentrate on breathing.
Review the procedure with the patient.
(practice with a dry run)
Block out large embrasures and inter-
proximal spaces to prevent tearing of the
impression material on removal
Dry teeth Pack arch with gauze. Block
salivary ducts if significant salivary flow
problem exists
19. Types of impression techniques that can be used inTypes of impression techniques that can be used in
partial denture construction:partial denture construction:
I- The anatomic form impression.I- The anatomic form impression.
II. The physiologic or the functional form.II. The physiologic or the functional form.
2- At the framework stage:2- At the framework stage:
The selective tissue placement impression technique.The selective tissue placement impression technique.
(Altered cast technique with rubber, zinc o or fluid wax methods )(Altered cast technique with rubber, zinc o or fluid wax methods )
Final impressionsFinal impressions
3- At the finished denture stage3- At the finished denture stage
a- old denture.a- old denture.
b- new denture.b- new denture.
The functional reline techniques using z o or rubber.The functional reline techniques using z o or rubber.
1- At the impression stage:1- At the impression stage:
-- Mclean’s and Hindel’s Methods.Mclean’s and Hindel’s Methods.
- One stage selected pressure impression technique.-- One stage selected pressure impression technique.-
20.
21. I. The anatomic formI. The anatomic form
impressionimpression
Is one stage impression technique thatIs one stage impression technique that
will produce a cast that does notwill produce a cast that does not
represent a functional relationshiprepresent a functional relationship
between the various supportingbetween the various supporting
structures. It represent the hard andstructures. It represent the hard and
soft tissues at rest.soft tissues at rest.
– Alginate impression material.Alginate impression material.
– Rubber base impression material.Rubber base impression material.
22. I. The anatomic formI. The anatomic form
impressionimpression
ModifiedModified stock traystock tray with modelingwith modeling
compound or waxcompound or wax
- Alginate impression material.- Alginate impression material.
Custom trayCustom tray on the diagnosticon the diagnostic
modelmodel
– Alginate impression material.Alginate impression material.
– Rubber base impression material.Rubber base impression material.
23. I.I. TheThe anatomicanatomic formform impressionimpression
Tooth supportedTooth supported PD can be constructed onPD can be constructed on
a cast obtained froma cast obtained from a single stage (pressurea single stage (pressure
free impression technique)free impression technique) that records thethat records the
teeth and supporting structures at rest in theirteeth and supporting structures at rest in their
anatomic form (anatomic form impression).anatomic form (anatomic form impression).
24. 1- Stock Tray1- Stock Tray
TechniqueTechnique
Standard technique for 95% of RPD Impressions.Standard technique for 95% of RPD Impressions.
Ideal stock tray technique includes someIdeal stock tray technique includes some
“customization” with periphery wax.“customization” with periphery wax.
Custom trays are only needed for the unique patientCustom trays are only needed for the unique patient
that a stock tray can’t be found that will cover thethat a stock tray can’t be found that will cover the
necessary structures.necessary structures.
25. Selection of the Stock TraysSelection of the Stock Trays
Select theSelect the suitable stock trayssuitable stock trays
(adapted, fitted and well(adapted, fitted and well
extended).extended). The sizeThe size of tray is selectedof tray is selected
so that the teeth sit centrally within theso that the teeth sit centrally within the
trough of the tray. The impressiontrough of the tray. The impression
should extend to the intended bordersshould extend to the intended borders
of the special tray.of the special tray.
26.
Check sizing for fit.
Check for tray length, use mouth mirror.
Beading or periphery wax to improve
adaptation.
Provide for a
relatively even
thickness of
impression material
Test tray in mouth,
Should not impinge
or bind anywhere.
Selection of the Stock TraysSelection of the Stock Trays
27. Selection of Stock TraySelection of Stock Tray
Provide for anProvide for an relatively even thicknessrelatively even thickness ofof
impression materialimpression material
Check sizing on study
cast for fit.
Test tray in mouth,
should not impinge or bind
anywhere.
Check for tray length, use
mouth mirror.
Beading or periphery wax
to improve adaptation.
Bend tray flange if
28. Test tray in mouth, it should not impingeTest tray in mouth, it should not impinge
or bind anywhere.or bind anywhere.
Check for tray length, use mouth mirror.Check for tray length, use mouth mirror.
29. ModifyModify the tray with impressionthe tray with impression
compound, pink wax orcompound, pink wax or
autopolymerising acrylic asautopolymerising acrylic as
appropriate,appropriate, to improve adaptationto improve adaptation
and extensionand extension
31. Posterior extension - add wax when necessary,
check with mirror and mouth movements.
Mandible - Always add periphery wax on lingual
surface of tray, from bicuspid back to assist
in displacing the tongue.
Maxilla - Add wax to posterior palatal border.
Warm wax for fitting, then chill with water prior
to impression.
32. To avoid bubbles use your finger to apply
alginate impression material to rests, guide
planes, occlusal surfaces and the gingival
33.
34. Apply alginate intoApply alginate into
critical areas with yourcritical areas with your
fingerfinger
Seat the tray slowlySeat the tray slowly
into positioninto position
Mandibular Impression:Mandibular Impression:
Instruct your patientInstruct your patient
place tongue on topplace tongue on top
and forward !and forward !
Gently massage the peripheral areasGently massage the peripheral areas
HoldHold tray until ready for removaltray until ready for removal
Remove impression in a “snap” movementRemove impression in a “snap” movement
35. Inspect Patient &Inspect Patient &
ImpressionImpression
Check patientCheck patient
Inspect areas that the framework contactsInspect areas that the framework contacts
(rests, guide planes, major/minor connector(rests, guide planes, major/minor connector
Disinfect the impressionDisinfect the impression,, instructorinstructor
approval within 5 minutesapproval within 5 minutes
Pour immediately!Pour immediately!
Imbibition – distortion by water absorbtion.
Syneresis – loss of water and shrinkage
distortion.
36. Care of Impressions and Making
Casts
• Carefully rinse theCarefully rinse the
impression with cold tapimpression with cold tap
water in order to removewater in order to remove
saliva* from the surface ofsaliva* from the surface of
the impressionthe impression
Failure to do so will result in a cast with a soft or chalky surface.Failure to do so will result in a cast with a soft or chalky surface.
*Saliva can be identified on the cast by sprinkling stoneSaliva can be identified on the cast by sprinkling stone
on the impression and gently rinsing it away with tapon the impression and gently rinsing it away with tap
water.water.
37. • Before pouring theBefore pouring the
cast remove allcast remove all
moisture with a gentlemoisture with a gentle
stream of air. Bestream of air. Be
careful not to overlycareful not to overly
dry the impression.dry the impression.
Never box an alginate impression with wax or aNever box an alginate impression with wax or a
mixture of plaster and pumice.mixture of plaster and pumice.
Care of Impressions and Making
Casts
38. Problem Probable cause
Trouble Shooting of Impressions and
Making Casts
Surface ofSurface of
the castthe cast
soft orsoft or
chalkychalky
• Saliva in the impression when castSaliva in the impression when cast
was pouredwas poured
• Improper water powder ratio usedImproper water powder ratio used
• Water from rinsing remains inWater from rinsing remains in
impressionimpression
DistortedDistorted
castcast
•Impression material separatedImpression material separated
from the trayfrom the tray
•Air inclusion in impression thatAir inclusion in impression that
distorts when stone is poureddistorts when stone is poured
39. Tray Selection for Partially Edentulous ArchTray Selection for Partially Edentulous Arch
•Adequate rigidityAdequate rigidity
•The proper size and shape of the trayThe proper size and shape of the tray to taketo take
advantage of the dimensional accuracy of theadvantage of the dimensional accuracy of the
impression materials and to include all necessaryimpression materials and to include all necessary
anatomic landmarks in the impressionanatomic landmarks in the impression
The keys to obtain an accurate alginate impression are:The keys to obtain an accurate alginate impression are:
The alginate bulk should beThe alginate bulk should be at least 3mmat least 3mm and shouldand should
also bealso be even thicknesseven thickness..
The choice of impression for RPD
framework:
Stock tray + alginate
40. Pouring the castPouring the cast
Measure the required amounts of water and powder
Carefully mix the stone in a vacuum power mixer
Using gentle vibration, flow the stone into the indentations in the
impression formed by the teeth.
Use a small brush to avoid trapping air
The bottom surface of the cast should be rough to facilitate
attachment of the base
Suspend the poured impression by the handle in the tray holder
Once the stone is fully set invert the cast and add a base. The base
should be 10-15 mm thick.
After 60 minutes of the first pour, separate the impression from the
cast.
Care of Impressions and Making
Casts
41. Double PourDouble Pour
TechniqueTechnique
Do not invert first pour of stone untilDo not invert first pour of stone until
initial set.initial set.
Then add the Base (10-15 mm thick).Then add the Base (10-15 mm thick).
42. Trimming the castTrimming the cast Trimming should not begin until
24 hours after pouring.
Before trimming the cast soak it in
clear slurry water for 5 minutes.
Failure to soak the cast in slurry
water will result in sludge
adhering to and damaging the
cast.
The cast should never be rinsed,
or soaked in water because
dental stone is water soluble.
The cast should be trimmed so that its base is
10-15 mm thick. The land should be 4 mm wide.
Care of Impressions and Making
Casts
43. 2- Impressions with2- Impressions with
Custom TraysCustom Trays
A- Alginate impressionA- Alginate impression with Customwith Custom
Trays.Trays.
B- Rubber base with Custom TraysB- Rubber base with Custom Trays..
44. Alginate or rubber base withAlginate or rubber base with
Custom TrayCustom Tray
An advanced technique required for a typical RPD
46. On the study castOn the study cast spacer is adapted on thespacer is adapted on the
teeth and residual ridgeteeth and residual ridge ( 4 mm for alginate( 4 mm for alginate
) to create uniform space for the) to create uniform space for the
impression material .impression material .
StopsStops can be made to help in accuratecan be made to help in accurate
seating of the tray, placed posteriorly inseating of the tray, placed posteriorly in
the edentulous ridge, and on the incisalthe edentulous ridge, and on the incisal
edges anteriorly.edges anteriorly.
Self-cure acrylic resin isSelf-cure acrylic resin is adapted to theadapted to the
cast.cast.
SPECIAL TRAY CONSTRUCTIONSPECIAL TRAY CONSTRUCTION
47. Custom Tray FabricationCustom Tray Fabrication
Block-out Soft,Block-out Soft,
Hard TissueHard Tissue
Undercut AreasUndercut Areas ..
48. Fabrication of CustomFabrication of Custom
TraysTrays
Apply Spacer for
Impression Material.
Elastomeric Material: 2-4
mm
Alginate: minimum 3 mm
49. Wax Spacer for theWax Spacer for the alginatealginate customcustom
tray:tray:
Adapt two layers of base plateAdapt two layers of base plate
wax to provide enough spacewax to provide enough space
for alginate bulkfor alginate bulk
The wax spacer isThe wax spacer is
short of the vestibuleshort of the vestibule
50. Paint the cast that may contact by the acrylic resinPaint the cast that may contact by the acrylic resin
tray material with a tinfoil substitute (Alcote)tray material with a tinfoil substitute (Alcote)
51.
52. Custom tray forCustom tray for
alginatealginate impressionimpression
materialmaterial
Custom tray forCustom tray for
rubber base/or PVSrubber base/or PVS
impression materialimpression material
Differences:Differences:
1. Thickness of the wax spacer1. Thickness of the wax spacer
2. Retention holes on the tray2. Retention holes on the tray
53. Tray Resin ManipulationTray Resin Manipulation
Rubber Mixing Bowls.Rubber Mixing Bowls.
Less Material Used.Less Material Used.
Dough Stage Does Not Stick to Bowl.Dough Stage Does Not Stick to Bowl.
55. • Mix the correct proportions of autopolymerizingMix the correct proportions of autopolymerizing
acrylic resin (powder : monomer= 3:1)acrylic resin (powder : monomer= 3:1)
• When the resin mix is no longer stringy and canWhen the resin mix is no longer stringy and can
be handled without adhering to the fingers, formbe handled without adhering to the fingers, form
it into a wafer size and adapt on the castit into a wafer size and adapt on the cast
• Maintain a uniform thickness of 2-3 mm forMaintain a uniform thickness of 2-3 mm for
rigidityrigidity
• Remove the gross excess with a sharp knifeRemove the gross excess with a sharp knife
while the resin is still softwhile the resin is still soft
• Form the handle with excess resin. PlaceForm the handle with excess resin. Place
additional monomer on the handle and tray toadditional monomer on the handle and tray to
provide a satisfactory union.provide a satisfactory union.
56. The extension of the tray covers the wholeThe extension of the tray covers the whole
vestibulevestibule (Unlike the complete denture(Unlike the complete denture
custom tray is 2-3 mm short of the vestibulecustom tray is 2-3 mm short of the vestibule
for border molding)for border molding)
to provide the vertical tissue stop andto provide the vertical tissue stop and
maintain the proper impression materialmaintain the proper impression material
thicknessthickness
Custom tray for RPD framework impression:
57. A- Custom Tray Fabrication forA- Custom Tray Fabrication for
Alginate impressionAlginate impression
• Allow the resin to cure, and remove the tray from the cast.Allow the resin to cure, and remove the tray from the cast.
• Carefully remove all wax from the tissue surface of the trayCarefully remove all wax from the tissue surface of the tray
with hot water. The impression materials we usewith hot water. The impression materials we use will notwill not
stick to the waxstick to the wax and there is risk of the impression materialand there is risk of the impression material
separating from the trayseparating from the tray
distorting the impression.distorting the impression.
58. • After Removal of the wax spacer.After Removal of the wax spacer.
• Perfect the borders of the tray with acrylic burs.Perfect the borders of the tray with acrylic burs.
• Place perforations (No. 8 bur size) in the tray at 4.5Place perforations (No. 8 bur size) in the tray at 4.5
mm interval tomm interval to
• ProvideProvide mechanical retention for alginate material.mechanical retention for alginate material.
Help in decreasing the dimensional changes of theHelp in decreasing the dimensional changes of the
materialmaterial
• Roughly polish the external surface of the tray.Roughly polish the external surface of the tray.
59.
60. Mandibular arch:Mandibular arch:
Custom tray forCustom tray for rubber base/orrubber base/or
PVSPVS impression materialimpression material
Only one layerOnly one layer of wax spacerof wax spacer
is needed.is needed.
Wax spacer is short of theWax spacer is short of the
vestibule.vestibule.
Apply the Alcote seperatingApply the Alcote seperating
medium onto the castmedium onto the cast
B- Custom Tray FabricationB- Custom Tray Fabrication
for Rubber Basefor Rubber Base
impressionimpression
61. Custom tray for theCustom tray for the
rubber baserubber base
impression material:impression material:
Perforations on thePerforations on the
traytray are notare not
necessary as thenecessary as the
adhesiveadhesive
provides reliableprovides reliable
retentionretention
Extra clearance for
the lingual frenum
62.
63. Tray Preparation:Tray Preparation:
Silicone and Rubber Base ImpressionsSilicone and Rubber Base Impressions
Adjust Length of Tray Borders
Remove Over-extension
Border Mold All Borders with Compound
65. Prepare Patient and MixingPrepare Patient and Mixing
AreaArea
When using elastomericWhen using elastomeric
impression materials:impression materials:
Use gauze and saliva ejector to remove excessUse gauze and saliva ejector to remove excess
saliva, prepare mixing area, and use an assistantsaliva, prepare mixing area, and use an assistant
67. Hard and Soft TissueHard and Soft Tissue
Extensions and BordersExtensions and Borders
CompletedCompleted
ImpressionsImpressions
68. ImpressionImpression
ProceduresProcedures
GaggingGagging
Thicker mix of AlginateThicker mix of Alginate
Mandible –contact with tongue can beMandible –contact with tongue can be
unavoidable. Proper fit of tray, shorten un-unavoidable. Proper fit of tray, shorten un-
necessary areasnecessary areas
Maxilla – Bend head forward, causes lift ofMaxilla – Bend head forward, causes lift of
soft palate. Beading wax to reduce alginatesoft palate. Beading wax to reduce alginate
posterior flowposterior flow
Tell patient, please do not move your tongue.Tell patient, please do not move your tongue.
69. Mark Denture BaseMark Denture Base
ExtensionsExtensions
The mark should be placed 3-4The mark should be placed 3-4
mm above the peripheral roll.mm above the peripheral roll.
Boxing the impressionBoxing the impression
70. Apply sticky wax to marked border.Apply sticky wax to marked border.
Boxing the Impression
71. Placement of WaxPlacement of Wax
Soft TissueSoft Tissue
Undercut AndUndercut And
Tongue AreasTongue Areas
Beading WaxBeading Wax
To All BordersTo All Borders
Boxing StripsBoxing Strips
To BeadedTo Beaded
AreasAreas
72. Box and Pour Master CastBox and Pour Master Cast
Carefully remove salivary residues andCarefully remove salivary residues and
dry the cast. Polysulfide casts need todry the cast. Polysulfide casts need to
be poured within 30 minutes.be poured within 30 minutes.
73. Use warm water to soften impression materialsUse warm water to soften impression materials
Separate the CastsSeparate the Casts
75. 1.1. Record supporting structure under someRecord supporting structure under some
loading.loading.
2.2. Maximum coverage of the base, soMaximum coverage of the base, so
distribute load over largest possible area.distribute load over largest possible area.
3.3. Direct force to the 1ry stress bearingDirect force to the 1ry stress bearing
area.area.
4.4. Equalize support derived from edentulousEqualize support derived from edentulous
ridges and abutment teeth.ridges and abutment teeth.
5.5. Minimize movement of the base.Minimize movement of the base.
Impression of distal extensionImpression of distal extension
bases must:bases must:
Maximum support,Maximum support,
less harm to the teeth and the ridgeless harm to the teeth and the ridge
76. Types of impression techniques that can beTypes of impression techniques that can be
used in partial dentureused in partial denture construction:construction:
I- The anatomic form.I- The anatomic form.
II. The physiologic or the functional form.II. The physiologic or the functional form.
2- At the framework stage:2- At the framework stage:
The selective tissue placement impression technique.The selective tissue placement impression technique.
(Altered cast technique with rubber, zinc o or fluid wax methods )(Altered cast technique with rubber, zinc o or fluid wax methods )
Final impressionsFinal impressions
3- At the finished denture stage3- At the finished denture stage
a- old denture.a- old denture.
b- new denture.b- new denture.
The functional reline techniques using z o or rubber.The functional reline techniques using z o or rubber.
1- At the impression stage:
- Mclean’s and Hindel’s Methods.
- One stage selected pressure impression technique.-.-
77. Record the ridge portion of the cast in itsRecord the ridge portion of the cast in its
functional form by placing an occlusalfunctional form by placing an occlusal
load on the impression trayload on the impression tray
1.1. Mclean’s physiologic technique.Mclean’s physiologic technique.
2.2. Hindel’s physiologic technique.Hindel’s physiologic technique.
3.3. One stage selected pressureOne stage selected pressure
impression technique.impression technique.
1-1- The functional (physiological)The functional (physiological)
form impression at the impressionform impression at the impression
stage:stage:
78. MCLEAN’S PHYSIOLOGIC METHOD
Mclean “the basic problem of partial denture stabilization
is to equalize the resilient and non resilient support”
clinical removable partial prosthodontics – Stewart. 3rd edition
79. Hydrocolloid impression over the first impression made
under finger pressure.
finger pressure not equal to biting pressure
Closely affect the direct retention
tissues are in constant stage of compression • ischemia and
bone resorption • premature contacts at rest.
HINDLE’S FINGER LOADING
81. 1)1) Special traySpecial tray is constructed on study cast as followis constructed on study cast as follow
One stage selected pressureOne stage selected pressure
impression techniqueimpression technique
It is a single impression made after theIt is a single impression made after the
mouth preparation & made before frameworkmouth preparation & made before framework
constructionconstruction
• 2 layers of base plate2 layers of base plate wax reliefwax relief is adapted on the teeth andis adapted on the teeth and
residual ridges .residual ridges .
• Aluminum foil is burnished over the wax .Aluminum foil is burnished over the wax .
• Cutting boxes through the foil and making occlusal stopsCutting boxes through the foil and making occlusal stops
which are placed over the remaining teeth to ensure properwhich are placed over the remaining teeth to ensure proper
seating of the tray .seating of the tray .
• Construct aConstruct a special trayspecial tray short 2 mm of the border .short 2 mm of the border .
• Remove wax and foil from the cast and wet the surface ofRemove wax and foil from the cast and wet the surface of
the cast.the cast.
82. 2)2) Softened compound is applied on the tissue surfaceSoftened compound is applied on the tissue surface
on the tray corresponding to the ridge , (first seat theon the tray corresponding to the ridge , (first seat the
compound on the cast to shape the compound beforecompound on the cast to shape the compound before
placement intra-oral) .placement intra-oral) .
3) Reheat compound and place it in the mouth .3) Reheat compound and place it in the mouth .
4) Apply compound to the borders for border molding .4) Apply compound to the borders for border molding .
5) Relief tissue surface of the compound5) Relief tissue surface of the compound exceptexcept 1ry1ry
stress bearing area .stress bearing area .
6) Rubber base impression with finger pressure .6) Rubber base impression with finger pressure .
7) Master cast, and framework construction .7) Master cast, and framework construction .
83. Wax Spacer for theWax Spacer for the alginatealginate custom tray:custom tray:
Adapt two layers of base plateAdapt two layers of base plate
wax to provide enough spacewax to provide enough space
for alginate bulkfor alginate bulk
The wax spacer is short of theThe wax spacer is short of the
vestibulevestibule
One Stage Selected Pressure ImpressionOne Stage Selected Pressure Impression
TechniqueTechnique
84. Apply Spacer for Impression
Material.
Elastomeric Material: 2-4 mm
Alginate: minimum 3 mm
One Stage Selected Pressure ImpressionOne Stage Selected Pressure Impression
TechniqueTechnique
85. Construction of the metallic frameworkConstruction of the metallic framework
86. Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
Technician reproduces your designed MAPTechnician reproduces your designed MAP
(Most Advantageous Position) based on the(Most Advantageous Position) based on the
tripod marks on the master casttripod marks on the master cast
87. Tripoding:Tripoding:
To be able to reproduce theTo be able to reproduce the
most advantageous positionmost advantageous position
of the cast at a later dateof the cast at a later date
Mark three horizontal linesMark three horizontal lines
at a fixed surveyor armat a fixed surveyor arm
vertical heightvertical height
88. Add wax into tooth and tissue undercut areas that willAdd wax into tooth and tissue undercut areas that will
be covered by the RPD framework except the plannedbe covered by the RPD framework except the planned
retention areas for active retainers. Trim excess waxretention areas for active retainers. Trim excess wax
with wax-cutting tool and surveyorwith wax-cutting tool and surveyor
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
89. Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
Place one layer of 22 gauge adhesive-coated castingPlace one layer of 22 gauge adhesive-coated casting
wax on the edentulous area as spacer for future pinkwax on the edentulous area as spacer for future pink
acrylic. Noted 2mm tooth-tissue junction is free of waxacrylic. Noted 2mm tooth-tissue junction is free of wax
spacer for direct metal contactspacer for direct metal contact
90. Complete wax block-out of the master cast based onComplete wax block-out of the master cast based on
MAP Noted the clear wax spacer was luted well toMAP Noted the clear wax spacer was luted well to
the cast by the green waxthe cast by the green wax
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
91. Wax is used to block out all undercut areas of theWax is used to block out all undercut areas of the
cast that will not be utilized by the RPD frameworkcast that will not be utilized by the RPD framework
active retainersactive retainers
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
92. Center the wax block-out master cast in the base ofCenter the wax block-out master cast in the base of
duplicating flaskduplicating flask
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
93. Pour the duplicating material (reversiblePour the duplicating material (reversible
hydrocolloid) into the flask when the materialhydrocolloid) into the flask when the material
reaches 125reaches 125°F°F
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
94. After the flask cools down for 1 hour in the ½ inchAfter the flask cools down for 1 hour in the ½ inch
running water the master cast is removed from therunning water the master cast is removed from the
duplicating materialduplicating material
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
95. Mix the casting investment material following theMix the casting investment material following the
recommended water/powder ratio in the vacuumrecommended water/powder ratio in the vacuum
mixer for 15 secondsmixer for 15 seconds
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
96. Pour the investment material into the duplicationPour the investment material into the duplication
flask beginning on one side on the vibratorflask beginning on one side on the vibrator
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
97. Allow the refractory cast to set for 1 hour beforeAllow the refractory cast to set for 1 hour before
separation from the duplicating flaskseparation from the duplicating flask
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
98. Check the accuracy of the duplicated refractory castCheck the accuracy of the duplicated refractory cast
with occlusal index recordwith occlusal index record
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
99. Complete the RPD framework wax pattern on theComplete the RPD framework wax pattern on the
refractory cast based on your submitted RPD designrefractory cast based on your submitted RPD design
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
100. Preformed plastic pattern of I-bar retainer is placedPreformed plastic pattern of I-bar retainer is placed
in position Add wax if necessary for correct taperin position Add wax if necessary for correct taper
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
101. Complete spruing for RPD waxed framework castingComplete spruing for RPD waxed framework casting
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
102. Complete RPD framework casting with sprues afterComplete RPD framework casting with sprues after
the investment and oxide layers are removedthe investment and oxide layers are removed
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
103. The RPD framework is adjusted and fitted onto theThe RPD framework is adjusted and fitted onto the
master castmaster cast
Laboratory stepsLaboratory steps
to generate RPDto generate RPD
frameworkframework
104. Seven working daysSeven working days
later!!!later!!!
Framework Ready for Try-InFramework Ready for Try-In
105. Inspection of the RPDInspection of the RPD
Framework CastingFramework Casting
Design Adaptation QualityDesign Adaptation Quality
106. Seat and Fit RPD FrameworkSeat and Fit RPD Framework
Inspect the tissue side of castingInspect the tissue side of casting
under the microscope and removeunder the microscope and remove
any irregularitiesany irregularities
Carefully fit & adjust the casting untilCarefully fit & adjust the casting until
excellent adaptation in the mouth is achievedexcellent adaptation in the mouth is achieved
107. Types of impression techniques that can beTypes of impression techniques that can be
used in partial dentureused in partial denture construction:construction:
I- The anatomic form.I- The anatomic form.
II. The physiologic or the functional form.II. The physiologic or the functional form.
2- At the framework stage:2- At the framework stage:
The selective tissue placement impression technique.The selective tissue placement impression technique.
(Altered cast technique with rubber, zinc o or fluid wax methods )(Altered cast technique with rubber, zinc o or fluid wax methods )
Final impressionsFinal impressions
3- At the finished denture stage3- At the finished denture stage
a- old denture.a- old denture.
b- new denture.b- new denture.
The functional reline techniques using z o or rubber.The functional reline techniques using z o or rubber.
1- At the impression stage:1- At the impression stage:
-- Mclean’s and Hindel’s Methods.Mclean’s and Hindel’s Methods.
- One stage selected pressure impression technique.-- One stage selected pressure impression technique.-
109. The casting is placed in the mouth andThe casting is placed in the mouth and
moved as in biting function with heavymoved as in biting function with heavy
pressure applied to the extension areapressure applied to the extension area
110. Adjustments are made to theAdjustments are made to the
framework in the areas that are bindingframework in the areas that are binding
with carbide burs and high speedwith carbide burs and high speed
grinding stonesgrinding stones
111. The idea of this techniqueThe idea of this technique::
An impression of the distally extendedAn impression of the distally extended
edentulous ridge is made by using anedentulous ridge is made by using an
impression tray attached to the metallicimpression tray attached to the metallic
framework , and the master cast is thenframework , and the master cast is then
altered to accommodate the new ridgealtered to accommodate the new ridge
impression.impression.
TheThe alteredaltered CCastast
TTechniqueechnique (Selective(Selective pressurepressure
impressionimpression technique)technique)
112. Prepare the tray:Prepare the tray:
The purpose of the tray is to carry a uniformThe purpose of the tray is to carry a uniform
thickness of the final impression material to thethickness of the final impression material to the
mouth without exerting pressure on themouth without exerting pressure on the
mucosa.mucosa.
Altered Cast ProcedureAltered Cast Procedure
The mucosa is recorded in aThe mucosa is recorded in a
compressed form so that thecompressed form so that the
degree of tissue warddegree of tissue ward
displacement is decreased intra-displacement is decreased intra-
orallyorally
The purpose of this technique is to obtain theThe purpose of this technique is to obtain the
maximum support possible from the edentulous areamaximum support possible from the edentulous area
of the extension partial denture.of the extension partial denture.
113.
114. 1) Made after construction of a framework1) Made after construction of a framework which iswhich is
made over a cast obtained from an anatomicmade over a cast obtained from an anatomic
impression .impression .
2) The framework is tried in patient mouth,2) The framework is tried in patient mouth, with the .with the .
rest on their seats occlusion is adjusted if need.rest on their seats occlusion is adjusted if need.
3) Draw the outline for the wax spacer on the3) Draw the outline for the wax spacer on the
edentulous areasedentulous areas of the master cast so that the waxof the master cast so that the wax
border is two millimeters inside the peripheral extensions ofborder is two millimeters inside the peripheral extensions of
the denture base. The spacer should stop at the internalthe denture base. The spacer should stop at the internal
finish line of the framework)finish line of the framework)
On the MASTER CAST , 1ry Stress bearing area is left withoutOn the MASTER CAST , 1ry Stress bearing area is left without
relief , Area that needs relief are relived using wax asrelief , Area that needs relief are relived using wax as
(internal oblique ridge , crest of the lower ridge(internal oblique ridge , crest of the lower ridge..
Altered Cast ProcedureAltered Cast Procedure
115. 4) Special tray is made on the ridge,4) Special tray is made on the ridge, attached mechanically toattached mechanically to
the framework.the framework.
5) Border molding5) Border molding with green stick compound .with green stick compound .
6) Relief holes6) Relief holes are prepared in the acrylic tray using a #8are prepared in the acrylic tray using a #8
round bur to permit the escape of excess impressionround bur to permit the escape of excess impression
material. This is done to reduce the possibility of softmaterial. This is done to reduce the possibility of soft
tissue distortion when the impression is made…tissue distortion when the impression is made…
7) A trial impression7) A trial impression is made using irreversible hydrocolloid.is made using irreversible hydrocolloid.
This impression is made to ensure that there is noThis impression is made to ensure that there is no
impingement of the border-molded tray on the underlyingimpingement of the border-molded tray on the underlying
soft tissue. If any pressure spots are noted, they should besoft tissue. If any pressure spots are noted, they should be
removed.removed.
116. 8) Final impression with Zn-Oxide impression8) Final impression with Zn-Oxide impression ( rubber base( rubber base
and fluid wax as IOWA WAX no.1 , KORRECTA no.4and fluid wax as IOWA WAX no.1 , KORRECTA no.4
also can be used ).also can be used ).
9) A wax block9) A wax block is placed on the occlusal surface of theis placed on the occlusal surface of the
impression tray. It should be trimmed so that twoimpression tray. It should be trimmed so that two
millimeters of space exist between the wax and themillimeters of space exist between the wax and the
opposing occlusal surfaces. A recording medium isopposing occlusal surfaces. A recording medium is
placed on the wax, and the framework is repositionedplaced on the wax, and the framework is repositioned
on the abutment teeth. The patient is then guided toon the abutment teeth. The patient is then guided to
closure in the desiredclosure in the desired jaw relationshipjaw relationship..
10) After the framework is removed,10) After the framework is removed, a face-bow transfera face-bow transfer
recording is made,recording is made,
11) The artificial teeth are selected11) The artificial teeth are selected (if it was missing) .(if it was missing) .
12) Alter the impression,12) Alter the impression, the distal extension area on thethe distal extension area on the
master cast are sawed off by a disc ,( 2 lines on eachmaster cast are sawed off by a disc ,( 2 lines on each
side , one vertical in the lingual sulcus and oneside , one vertical in the lingual sulcus and one
horizontal distal to last abutment ).horizontal distal to last abutment ).
117. 13) Retentive grooves13) Retentive grooves are then cut on the side of the cast.are then cut on the side of the cast.
14) The framework with the impression is reseated14) The framework with the impression is reseated on theon the
cast and ( green stick compound is placed on thecast and ( green stick compound is placed on the
rest and indirect retainers my aid in ensuring properrest and indirect retainers my aid in ensuring proper
seating during pouring impression) .seating during pouring impression) .
15) Impression is15) Impression is boxedboxed Irreversible hydrocolloid is usedIrreversible hydrocolloid is used
for the boxing technique.for the boxing technique.
16) Edentulous area16) Edentulous area is poured with stoneis poured with stone ( with different( with different
color than original cast ).color than original cast ).
N;B Auto-polymerizing resin placed under the most distalN;B Auto-polymerizing resin placed under the most distal
extension of the framework in the edentulous areasextension of the framework in the edentulous areas
to act as a tissue stop during processing of theto act as a tissue stop during processing of the
acrylic.acrylic.
118. The advantage of the alteredThe advantage of the altered
cast procedure:cast procedure:
1.1. Accurate relationship between the dentureAccurate relationship between the denture
base and the metal framework is establishedbase and the metal framework is established
prior to tooth arrangement which shouldprior to tooth arrangement which should
result in less occlusal adjustment at the timeresult in less occlusal adjustment at the time
of insertion.of insertion.
2.2. To obtain the maximum possible supportTo obtain the maximum possible support
from the distal extension base of the RPDfrom the distal extension base of the RPD
and to accurately relate the soft tissueand to accurately relate the soft tissue
surface of the denture base to the metalsurface of the denture base to the metal
framework.framework.
119.
120. The casting which has beenThe casting which has been
physiologically adjusted is placed onphysiologically adjusted is placed on
the master castthe master cast
121. A single layer of baseplate wax is placed over the edentulousA single layer of baseplate wax is placed over the edentulous
area to provide a space for the impression material.area to provide a space for the impression material.
Warm the metal casting and reseat on the master castWarm the metal casting and reseat on the master cast
ensuring that all rests are well in place.ensuring that all rests are well in place.
122. Remove some wax from the denture base connector areaRemove some wax from the denture base connector area
to provide for the mechanical lock of the acrylic to the metal.to provide for the mechanical lock of the acrylic to the metal.
123. On theOn the MASTER CASTMASTER CAST , 1, 1ryry
Stress bearingStress bearing
area is left without reliefarea is left without relief , Area that needs relief, Area that needs relief
are relived usingare relived using wax as (internal oblique ridge ,wax as (internal oblique ridge ,
crest of the lower ridge ).crest of the lower ridge ).
124. Prepare the tray:Prepare the tray:
The purpose of the tray is to carry a uniformThe purpose of the tray is to carry a uniform
thickness of the final impression material to thethickness of the final impression material to the
mouth without exerting pressure on the mucosa.mouth without exerting pressure on the mucosa.
125. When the plastic tray material is cured theWhen the plastic tray material is cured the
entire cast is submerged in the warm water forentire cast is submerged in the warm water for
few seconds for easy separation, then the waxfew seconds for easy separation, then the wax
spacer is removed.spacer is removed.
126. The plastic tray is trimmed and polished.The plastic tray is trimmed and polished.
127. The tray is placed in the mouth andThe tray is placed in the mouth and
checked for proper peripheral extension.checked for proper peripheral extension.
128. Border extensions are refined withBorder extensions are refined with
modeling compound, then cut back tomodeling compound, then cut back to
allow room for the impression material.allow room for the impression material.
129. Vent holes are placed in the plastic trayVent holes are placed in the plastic tray
near the finish line for escape of excessnear the finish line for escape of excess
impression materialimpression material
131. Material is mixed, the tray is loaded, andMaterial is mixed, the tray is loaded, and
the casting is firmly seated on the teeththe casting is firmly seated on the teeth
and held in position over the rests until itand held in position over the rests until it
is completely setis completely set
Do not place or allow movement onDo not place or allow movement on
the edentulous area!the edentulous area!
132. Physiologic AdjustmentPhysiologic Adjustment & Altered Cast& Altered Cast
Impression for extension base RPDImpression for extension base RPD
Fabricate the detachable tray 24hrs inFabricate the detachable tray 24hrs in
advance. Connect to the casting withadvance. Connect to the casting with
cold cured acrylic once the seating andcold cured acrylic once the seating and
physiologic adjustment are completed.physiologic adjustment are completed.
Purpose:Purpose:
To obtain the maximum tissue supportTo obtain the maximum tissue support
from the extension edentulous areafrom the extension edentulous area
Border molding & final impressionBorder molding & final impression
Do not over load the material!Do not over load the material!
Critical area: metal-acrylic junctionCritical area: metal-acrylic junction
133.
134. Trim the impression material exactly to theTrim the impression material exactly to the
metal finish line on the tissue surfacemetal finish line on the tissue surface
135. Cast AlterationCast Alteration ::
The edentulous area of the master cast is removed, and theThe edentulous area of the master cast is removed, and the
metal casting is seated in place on the teeth.metal casting is seated in place on the teeth.
The casting is secured to the stone cast with sticky wax.The casting is secured to the stone cast with sticky wax.
Note: Only the metal will touch the cast.Note: Only the metal will touch the cast.
All impression areas must be out of contactAll impression areas must be out of contact..
136. Physiologic AdjustmentPhysiologic Adjustment & Altered Cast Impression& Altered Cast Impression
for extension base RPDfor extension base RPD
Secure the casting onto theSecure the casting onto the
master cast with waxmaster cast with wax
Follow the same manner asFollow the same manner as
complete denture to bead and boxcomplete denture to bead and box
the alter cast impressionthe alter cast impression
Preserve the 2-3mm peripheralPreserve the 2-3mm peripheral
flange and 5mm land areaflange and 5mm land area
Create mechanical retention on the master castCreate mechanical retention on the master cast
137. Retention grooves are placed in theRetention grooves are placed in the
cast. The impression is beaded andcast. The impression is beaded and
boxed and ready to be poured inboxed and ready to be poured in
vacuum-mixed stone.vacuum-mixed stone.
138. Physiologic AdjustmentPhysiologic Adjustment & Altered Cast Impression& Altered Cast Impression
for extension base RPDfor extension base RPD
1. Pour the altered cast1. Pour the altered cast
impression after beading &impression after beading &
boxingboxing
2. Remove the impression2. Remove the impression
tray from the casting oncetray from the casting once
the stone setsthe stone sets
139. The Altered Cast with the Edentulous AreaThe Altered Cast with the Edentulous Area
RepouredRepoured
This produces the best possible support andThis produces the best possible support and
orientation of the metal casting to theorientation of the metal casting to the
remaining teethremaining teeth
Effective preventive measure to protect abutmentEffective preventive measure to protect abutment
teeth by providing 2-3 times greater mucosalteeth by providing 2-3 times greater mucosal
support and minimizing denture movement.support and minimizing denture movement.
140. Physiologic AdjustmentPhysiologic Adjustment & Altered Cast Impression& Altered Cast Impression
for extension base RPDfor extension base RPD
1. Pour the altered cast impression after beading &1. Pour the altered cast impression after beading &
boxingboxing
2. Remove the impression tray from the casting once the2. Remove the impression tray from the casting once the
stone setsstone sets
3. Fabricate the record base & wax rim on the new3. Fabricate the record base & wax rim on the new
altered castaltered cast
141. Types of impression techniques that can beTypes of impression techniques that can be
used in partial dentureused in partial denture construction:construction:
I- The anatomic form.I- The anatomic form.
II. The physiologic or the functional form.II. The physiologic or the functional form.
2- At the framework stage:2- At the framework stage:
The selective tissue placement impression technique.The selective tissue placement impression technique.
(Altered cast technique with rubber, zinc o or fluid wax methods )(Altered cast technique with rubber, zinc o or fluid wax methods )
Final impressionsFinal impressions
3- At the finished denture stage3- At the finished denture stage
a- old denture.a- old denture.
b- new denture.b- new denture.
1- At the impression stage:1- At the impression stage:
-- Mclean’s and Hindel’s Methods.Mclean’s and Hindel’s Methods.
- One stage selected pressure impression technique.-- One stage selected pressure impression technique.-
The functional reline techniques using z o, rubberThe functional reline techniques using z o, rubber or fluid waxor fluid wax ..
142. The functional relining impressionThe functional relining impression
technique at the finished denture stagetechnique at the finished denture stage
The idea of this techniqueThe idea of this technique ::
1-1- For New denture:For New denture: constructed from singleconstructed from single
anatomic impression to avoid movement on theanatomic impression to avoid movement on the
edentulous area after application of masticatory load.edentulous area after application of masticatory load.
2- After denture use for many years2- After denture use for many years , a, a
combination of occlusal wear and sinking of thecombination of occlusal wear and sinking of the
denture following alveolar resorption occurs. Sodenture following alveolar resorption occurs. So
functional impression is required to correct thisfunctional impression is required to correct this
143. 1-1- Borders are shortenedBorders are shortened and dentureand denture
base is relieved (to create space for impressionbase is relieved (to create space for impression
material).material).
2- Border molding2- Border molding using Green Stickusing Green Stick
Compound impression.Compound impression.
3- Zinc Oxide impression3- Zinc Oxide impression is done .is done .
4- Overall alginate impression4- Overall alginate impression is made .is made .
5- Cast is poured , relining , adjust5- Cast is poured , relining , adjust
occlusal errors .occlusal errors .
Done after denture construction, (open mouthDone after denture construction, (open mouth
procedure )procedure )
The functional relining impressionThe functional relining impression
technique at the finished denture stagetechnique at the finished denture stage
144.
145. DisadvantagesDisadvantages::
a) Failure to maintain the correcta) Failure to maintain the correct
relationship between therelationship between the
framework and the abutmentframework and the abutment
teeth.teeth.
b) Failure to maintain correctb) Failure to maintain correct
occlusion.occlusion.
146. The functional impressionThe functional impression
techniques can be performed withtechniques can be performed with
different impression materialsdifferent impression materials
Rubber base impression materialRubber base impression material
Zinc oxide and eugenol paste orZinc oxide and eugenol paste or
The FluidFluid waxwax impression technique
After border molding with green stickAfter border molding with green stick
compoundcompound
147. Fluid wax are waxes that areFluid wax are waxes that are
firm at room temperature andfirm at room temperature and
have the ability to flow inhave the ability to flow in
mouth temperaturesmouth temperatures
(Lowa wax no. 1 and Korrecta(Lowa wax no. 1 and Korrecta
wax no 4)wax no 4)
148. The fluid wax are waxesThe fluid wax are waxes
that firm at roomthat firm at room
temperature but it have antemperature but it have an
ability to flow when put inability to flow when put in
mouth temperature.mouth temperature.
149. In fluid wax impression technique, the key of
using it are space and time.
The borders made should be short for all
movable tissues which is not more than 2 mm
short. This is due to the insufficient strength
of fluid wax to support itself beyond the
distance. Moreover, when the tray must
remain in place about 5 to 7 minutes upon
introduced into the patients mouth.
This allow the flow of wax and prevent the
buildup pressure under the tray.