Impression c d

Impression Technique forImpression Technique for
complete denturescomplete dentures
Dr. M A Abdullah M.D.S.Dr. M A Abdullah M.D.S.
Associate Professor of Prosthodontics,Associate Professor of Prosthodontics,
College of Dentistry, King Saud University.College of Dentistry, King Saud University.
Saudi Arabia.Saudi Arabia.
References.
Heartwell C M , Rahn A O ,Text book of complete
Dentures,5th ed., Williams & Wilkins Co. Philadelphia,
1993.

Complete Denture impressionComplete Denture impression
Is a negative registration of the entire denture bearing,Is a negative registration of the entire denture bearing,
stabilizing and border seal areas presentstabilizing and border seal areas present
in the edentulous mouthin the edentulous mouth

Objectives of complete denture impressionObjectives of complete denture impression
Preservation of supporting tissuesPreservation of supporting tissues
RetentionRetention
StabilityStability
SupportSupport
EstheticsEsthetics

Impression TechniquesImpression Techniques
CLOSE MOUTH OR PRESSURE IMPRESSIONCLOSE MOUTH OR PRESSURE IMPRESSION
TECHNIQUE:TECHNIQUE:
Records impression in a condition that assumesRecords impression in a condition that assumes
under masticatory load.under masticatory load.
NON PRESSURE OR MUCOSTATIC IMPRESSIONNON PRESSURE OR MUCOSTATIC IMPRESSION
TECHNIQUE :TECHNIQUE :
Records impression of the tissue in an anatomicalRecords impression of the tissue in an anatomical
form without pressure.form without pressure.
SELECTIVE COMPRESSION IMPRESSION TECHNIQUE :SELECTIVE COMPRESSION IMPRESSION TECHNIQUE :
Records impression with more compression on the tissueRecords impression with more compression on the tissue
in certain selected areas than on other areas.in certain selected areas than on other areas.

This technique believes that occlusal loading duringThis technique believes that occlusal loading during
impression will record the tissues in a functional form asimpression will record the tissues in a functional form as
during swallowing and eatingduring swallowing and eating
Advocates of this technique believe that the peripheryAdvocates of this technique believe that the periphery
of dentures must be established during functionof dentures must be established during function
Pressure or Close Mouth ImpressionPressure or Close Mouth Impression
TechniqueTechnique

Procedure:Procedure:
Construct custom trays with compound occlusion rims.Construct custom trays with compound occlusion rims.
Adjust occlusion rims for interocclusal distance andAdjust occlusion rims for interocclusal distance and
uniform contact in centric and eccentric positions.uniform contact in centric and eccentric positions.
Load the impression material into both the custom traysLoad the impression material into both the custom trays
simultaneously.simultaneously.
Have the patient close the mouth with the custom traysHave the patient close the mouth with the custom trays
in mouth and moves the jaw through functionalin mouth and moves the jaw through functional
movements to record the impression.movements to record the impression.
TechniqueTechnique

Disadvantages:Disadvantages:
The total time during 24 hours associated with directsThe total time during 24 hours associated with directs
functional occlusal force application to periodontal tissuefunctional occlusal force application to periodontal tissue
is 17.5 minutes .is 17.5 minutes .Thus dentures are in function for a shortThus dentures are in function for a short
period of time each day.period of time each day.
Dentures will fit well during mastication ,and will lift up atDentures will fit well during mastication ,and will lift up at
rest due to tissue rebound.rest due to tissue rebound. This results in prematureThis results in premature
contacts.contacts.
Due to constant pressure on the tissues,Due to constant pressure on the tissues, mucosalmucosal
tissue reaction and resorption may result.tissue reaction and resorption may result.
Graf H. Dent Clin North.1969;13:659Graf H. Dent Clin North.1969;13:659--665665
TechniqueTechnique

Non Pressure or Mucostatic ImpressionNon Pressure or Mucostatic Impression
TechniqueTechnique
Advocates of this technique believe that impression must
be recorded in an anatomic form of the tissues (resting form).
Dentures constructed by mucostatic impression technique
have shorter flanges.
Short flanges are used to prevent the dentures moving in
lateral direction and NOT for border seal.
Metal bases which are dimensionally stable are used.

Dentures do not cover broad areasDentures do not cover broad areas
Inadequate supportInadequate support
Short flanges do not support the lips and cheeksShort flanges do not support the lips and cheeks
Non Pressure or Mucostatic ImpressionNon Pressure or Mucostatic Impression
TechniqueTechnique
Disadvantages:

Selective Pressure Impression TechniqueSelective Pressure Impression Technique
Primary stress bearing areas are recorded under
pressure
The secondary stress bearing areas are recorded with
minimal pressure
Peripheral areas are recorded under compression to
develop seal
The pressure can be selectively applied to the tissue
by the custom trays for making final impression
It combines pressure and minimum pressure principles inIt combines pressure and minimum pressure principles in
making impression for maxilla and mandible:making impression for maxilla and mandible:

Anatomy of edentulous maxillaAnatomy of edentulous maxilla
Labial and buccal frenum andLabial and buccal frenum and
sulcussulcus
PteregomandibularPteregomandibular rapheraphe oror
ligamentligament
Hamular notchHamular notch
Incisive papillaIncisive papilla
FoviaFovia palatinuspalatinus
MidpalatineMidpalatine suturesuture
Ridge, cuspid eminence , malarRidge, cuspid eminence , malar
bonebone

Anatomy of edentulous maxillaAnatomy of edentulous maxilla
Primary stress bearingPrimary stress bearing
area:area:
Horizontal portion of hadHorizontal portion of had
palatepalate (1)(1)
Secondary stress bearingSecondary stress bearing
area:area:
ridge crestridge crest (2).(2).
Non stress bearing areaNon stress bearing area
ridge slopesridge slopes ( n/c )( n/c )

Anatomy of Edentulous MandibleAnatomy of Edentulous Mandible
Labial, buccal & lingual frenaeLabial, buccal & lingual frenae
Labial , buccal and lingual sulcusLabial , buccal and lingual sulcus
Buccal shelfBuccal shelf
Masseter grooveMasseter groove
Retromolar padRetromolar pad

Anatomy of edentulous MandibleAnatomy of edentulous Mandible
Primary stress bearing area:Primary stress bearing area:
buccal shelf & retromaolarbuccal shelf & retromaolar
padpad (1)(1)
Secondary stress bearingSecondary stress bearing
areaarea
Residual ridge & genialResidual ridge & genial
tuberclestubercles (2)(2)
Non stress bearing areaNon stress bearing area
Labial and lingual inclinesLabial and lingual inclines
(n/c)(n/c)

PreliminaryPreliminary Impression of Maxillary ArchImpression of Maxillary Arch
Select edentulous perforated
stock metal tray 6 mm larger
than the outside surface of the
ridge
Examine the extension of tray
flange at labial and buccal
areas
Examine the posterior
extension of the tray by
dropping the handle down . It
must cover the hamular
notches and vibrating line

Preliminary Impression of MaxillaryPreliminary Impression of Maxillary
edentulous archedentulous arch
Load the tray with alginate
impression material
Place small amount of impression
material in the rugea area of the
hard palate
Place the tray in the mouth. Hold
the impression tray in the middle of
the palate until the material sets
Impression in modeling plasticImpression in modeling plastic
impression compound materialimpression compound material

ConstructionConstruction of Maxillary Custom Trayof Maxillary Custom Tray
Draw the outline of wax spacer inDraw the outline of wax spacer in
pencil on the diagnostic cast.pencil on the diagnostic cast.
Do not cover the post palatal sealDo not cover the post palatal seal
area with wax spacer ( arrow).area with wax spacer ( arrow).
Provide tissue stops at the molarProvide tissue stops at the molar
and incisal regions.and incisal regions.

Advantages of Not Covering the Post palatalAdvantages of Not Covering the Post palatal
Seal Area with Wax SpacerSeal Area with Wax Spacer
Completed custom tray will contact theCompleted custom tray will contact the
post palatal seal areapost palatal seal area
Additional stress can be placed at thisAdditional stress can be placed at this
area during impression makingarea during impression making

Border moldingBorder molding
The shaping of the border areas of
an impression tray by functional
or manual manipulation of
the tissue adjacent to the borders
to duplicate the contour and size
of the vestibule
The glossary of prosthodontic,term,7thed.1999The glossary of prosthodontic,term,7thed.1999

Adjusting Maxillary Custom TrayAdjusting Maxillary Custom Tray
Reduce the flanges of the trayReduce the flanges of the tray
2 mm short from the sulcus2 mm short from the sulcus
Adjust labial frenal attachmentAdjust labial frenal attachment
Adjust buccal frenal attachmentAdjust buccal frenal attachment
Do not remove the wax spacerDo not remove the wax spacer
until final impression is madeuntil final impression is made

Establishing Vibrating LineEstablishing Vibrating Line
PlacePlace ““TT”” on the crest ridge ,move posteriorly until iton the crest ridge ,move posteriorly until it
dips into hamular notch. Join the hamular notchesdips into hamular notch. Join the hamular notches
with pencil across the fovia palatinae. Confirm thewith pencil across the fovia palatinae. Confirm the
vibrating line by asking the patient to say series ofvibrating line by asking the patient to say series of
shortshort ‘‘AHAH’’ soundssounds..
TheThe junction between thejunction between the
movable and immovablemovable and immovable
soft palatesoft palate through thethrough the
foveae palatinae is calledfoveae palatinae is called
vibratingvibrating lineline

Posterior Border of Maxillary Custom TrayPosterior Border of Maxillary Custom Tray
The posterior borderThe posterior border
of the custom tray must coverof the custom tray must cover
the hamular notchesthe hamular notches
and extend approximatelyand extend approximately
2 mm posterior to2 mm posterior to
the vibrating line acrossthe vibrating line across
the palatethe palate

Border MoldingBorder Molding
After tempering in water
bath at 70 F, border mold it
in the mouth
Soften the modeling plastic
impression compound over
the alcohol torch flame, and
place it over the border of
the tray.

Border Molding Labial SulcusBorder Molding Labial Sulcus
In the region of labial sulcus,In the region of labial sulcus,
the upper lip isthe upper lip is elevatedelevated
andand extended outextended out and then pulledand then pulled
downward and inwarddownward and inward..
ReRe--soften the compound and repeat this proceduresoften the compound and repeat this procedure
to establish proper border molding.to establish proper border molding.

Border Molding Buccal SulcusBorder Molding Buccal Sulcus
In the region of buccal frenum , the cheek is elevatedIn the region of buccal frenum , the cheek is elevated
and then pulled outward ,downward and inward .and then pulled outward ,downward and inward .
Move the cheek backward and forward to simulateMove the cheek backward and forward to simulate
movement of buccal frenum as in function during eatingmovement of buccal frenum as in function during eating
and smilingand smiling

Border Molding of Buccal Sulcus atBorder Molding of Buccal Sulcus at
TuberosityTuberosity
The posterior buccal flange at the tuberosity region isThe posterior buccal flange at the tuberosity region is
border molded when the cheek is extended outward,border molded when the cheek is extended outward,
downwarddownward and inwardand inward
With the tray in place, have the patient openWith the tray in place, have the patient open
mouth widely and move the jaw laterally tomouth widely and move the jaw laterally to
establish the width of the sulcusestablish the width of the sulcus

Border Molding the Post palatal Seal AreaBorder Molding the Post palatal Seal Area
Place strip of softened compound atPlace strip of softened compound at
the posterior border of the custom traythe posterior border of the custom tray
and seat it firmly in the mouthand seat it firmly in the mouth
Mark vibrating line and post palatal sealMark vibrating line and post palatal seal
area with indelible pencilarea with indelible pencil
Seat the tray again firmly in the mouthSeat the tray again firmly in the mouth
for the indelible pencil mark to befor the indelible pencil mark to be
transferred to the tray . Remove excesstransferred to the tray . Remove excess
of modeling compound .of modeling compound .

Relief for ImpressionRelief for Impression
Place holes in the palate of the custom tray with no. 6Place holes in the palate of the custom tray with no. 6
round bur to provide escape ways for the finalround bur to provide escape ways for the final
impression materialimpression material
The holes provide relief while making final impression atThe holes provide relief while making final impression at
mid palatine raphe and hard palatal regionsmid palatine raphe and hard palatal regions

Practice Positioning Border Molded Tray inPractice Positioning Border Molded Tray in
Mouth Before Making Final ImpressionMouth Before Making Final Impression
Place the tray in mouth with labial fremum in the labialPlace the tray in mouth with labial fremum in the labial
notch.notch.
Place index fingers at first molar region and seat the trayPlace index fingers at first molar region and seat the tray
until the posterior border of the tray fits into hamularuntil the posterior border of the tray fits into hamular
notches and across the palatenotches and across the palate
Hold the tray in position with fingers placed in the palatalHold the tray in position with fingers placed in the palatal
regionregion

Making Final ImpressionMaking Final Impression
The mixed impression material isThe mixed impression material is
placed on the tray with bordersplaced on the tray with borders
coveredcovered
Seat the tray in the mouth and borderSeat the tray in the mouth and border
mold in the posterior region first andmold in the posterior region first and
then in the anterior regionthen in the anterior region
coveredcovered
Do not load the tray with excess of material
coveredcovered
coveredcovered

Final Rubber Base Impression with OutlineFinal Rubber Base Impression with Outline
LandmarksLandmarks
1.labial frenum1.labial frenum
2. Labial flange2. Labial flange
3. Buccal frenum3. Buccal frenum
4. Bucaal flange4. Bucaal flange
5. Pteromandibular raphe5. Pteromandibular raphe
6. Fovea palatinae6. Fovea palatinae
7. Vibrating line7. Vibrating line
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44
55 66 77

Preliminary Mandibular ImpressionPreliminary Mandibular Impression
Select perforated lower metalSelect perforated lower metal
tray with 6 mm larger than thetray with 6 mm larger than the
outside surface of labial andoutside surface of labial and
lingual ridgelingual ridge
Raise the handle and examineRaise the handle and examine
extension of tray flange atextension of tray flange at
labial, buccal ,lingual andlabial, buccal ,lingual and
retromolar pad It should coverretromolar pad It should cover
all these areasall these areas
Adapt strip of utility wax onAdapt strip of utility wax on
the borders of the metal traythe borders of the metal tray
Load the tray with mixedLoad the tray with mixed
alginate material. Place thealginate material. Place the
tray in the mouth with thetray in the mouth with the
tongue raised slightlytongue raised slightly

Preliminary Mandibular Impression with modeling plasticPreliminary Mandibular Impression with modeling plastic
impression compoundimpression compound
Soften the modeling plastic
impression compound in a water
bath.
The mandibular impression.
soften the impression borders
using alcohol torch , temper it in
water bath.
Reintroduce it in the mouth and
activate the tissues to refine the
impression.

Construction of Mandibular Custom TrayConstruction of Mandibular Custom Tray
Draw the outline for wax spacer in pencil onDraw the outline for wax spacer in pencil on
the diagnostic cast.the diagnostic cast.
Do not cover the buccal shelf areas with wax spacerDo not cover the buccal shelf areas with wax spacer..
Make additional tissue stops at the anterior regions.Make additional tissue stops at the anterior regions.

AdvantagesAdvantages
Completed custom try will contact the buccal shelf areas
Additional stress can be placed at these areas during the final
impression
The part of the tray in contact with buccal shelf areas act as
tissue stops

Adjusting Mandibular Custom TrayAdjusting Mandibular Custom Tray
Reduce the flanges of custom trayReduce the flanges of custom tray
2 mm short of the tissue reflection2 mm short of the tissue reflection
of the:of the:
Labial, buccal and lingual sulcuiLabial, buccal and lingual sulcui
and frenal attachmentsand frenal attachments
Do not remove the wax spacer until final impression is madeDo not remove the wax spacer until final impression is made

Border Molding Mandibular Labial FlangeBorder Molding Mandibular Labial Flange
Start border molding beginningStart border molding beginning
with labial flange (1) , buccalwith labial flange (1) , buccal
flanges (2) and finally lingualflanges (2) and finally lingual
flanges (3)flanges (3)
In the region of labial sulcus , theIn the region of labial sulcus , the
lower lip is lifted outward, upwardlower lip is lifted outward, upward
and inwardand inward..
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Border Molding The Labial and Buccal Flange ofBorder Molding The Labial and Buccal Flange of
Lower TrayLower Tray
Anatomical ConsiderationsAnatomical Considerations
The mandibular labial frenumThe mandibular labial frenum
contains a band of fibrouscontains a band of fibrous
connective tissue that is attached toconnective tissue that is attached to
orbicularis oris. Therefore , the labialorbicularis oris. Therefore , the labial
frenum is active.frenum is active.

Border molding the Buccal flange of lowerBorder molding the Buccal flange of lower
traytray
The buccal flange must not extend lateral toThe buccal flange must not extend lateral to
external oblique ridgeexternal oblique ridge
The disto buccal flange must record theThe disto buccal flange must record the
masseter groove and the superior border ofmasseter groove and the superior border of
retromolar padretromolar pad
In the region of buccal frenum, the cheekIn the region of buccal frenum, the cheek
is lifted outward, upward inward, backwardis lifted outward, upward inward, backward
and forward to simulate the movement ofand forward to simulate the movement of
buccal frenumbuccal frenum
Record masseter groove by instructing theRecord masseter groove by instructing the
patient to exert closing force and the dentistpatient to exert closing force and the dentist
exerting a downward pressure on the trayexerting a downward pressure on the tray

Border Molding the Lingual FlangeBorder Molding the Lingual Flange
The lingual flange is border moldedThe lingual flange is border molded
in 5 stepsin 5 steps
Step 1.The extension of anteriorStep 1.The extension of anterior
lingual flange of the tray is limited bylingual flange of the tray is limited by
the lingual frenum and sublingualthe lingual frenum and sublingual
folds, and is 2mm short of the tissuesfolds, and is 2mm short of the tissues
Step 2. Place the softened modelingStep 2. Place the softened modeling
compound on the border of the traycompound on the border of the tray
extending between premylohyoidextending between premylohyoid
fossafossa
nstruct the patient to protrude the tongue tonstruct the patient to protrude the tongue to
stablish the length of the sulcusstablish the length of the sulcus

Establish Length and Thickness the LingualEstablish Length and Thickness the Lingual
FlangeFlange
Step 2. Instruct the patient to protrude the tongue toStep 2. Instruct the patient to protrude the tongue to
establish the length of the sulcusestablish the length of the sulcus
The compound is reThe compound is re--softened and placed again in thesoftened and placed again in the
mouth and the patient is instructed to push the tonguemouth and the patient is instructed to push the tongue
forcefully against the palate to determine the thickness offorcefully against the palate to determine the thickness of
the flangethe flange

Border Molding the Lingual FlangeBorder Molding the Lingual Flange
A. The lingual flange is extendedA. The lingual flange is extended
to the most superior level of theto the most superior level of the
floor of the mouthfloor of the mouth
B. Slight pressure on mucosaB. Slight pressure on mucosa
overlying lingual slope ensures aoverlying lingual slope ensures a
broader seal when tongue is atbroader seal when tongue is at
restrest

Border Molding of Lingual FlangeBorder Molding of Lingual Flange
Step 3. Modeling compound is added
to the lingual borders from
premylohyoid fossae posteri0rly on
both sides .After placing the tray in
the mouth, instruct the patient to
protrude the tongue .This procedure
establishes the length h of the sulcus
Step 4.Repeat step 3 and have the
patient move the tongue laterally and
touch the corners of the mouth
Remove the wax spacer from the tray

Border Molding Lingual FlangeBorder Molding Lingual Flange
Step 5.Add modeling compoundStep 5.Add modeling compound
on the distal end of the lingualon the distal end of the lingual
flange of the tray.flange of the tray.
Place the tray in the mouth andPlace the tray in the mouth and
have the patient protrude thehave the patient protrude the
tongue to activate the superiortongue to activate the superior
constrictor of the pharynxconstrictor of the pharynx
muscles (1) that support themuscles (1) that support the
retromylohyoid curtain andretromylohyoid curtain and
pterygomandibular raphepterygomandibular raphe
Instruct the patient to forcefullyInstruct the patient to forcefully
close the mouth .The resultingclose the mouth .The resulting
contraction of the medialcontraction of the medial
pterygoid muscles (2) limits thepterygoid muscles (2) limits the
retromylohyoid area.retromylohyoid area.
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Final Rubber Base ImpressionFinal Rubber Base Impression
Place the tray with impression material inPlace the tray with impression material in
patients mouth. Manipulate lips andpatients mouth. Manipulate lips and
cheekscheeks
..
Have the patient move the tongue andHave the patient move the tongue and
keep it in protruded position till thekeep it in protruded position till the
impression sets.impression sets.

Defects in ImpressionDefects in Impression
In correct tray position in mouth resulting in underIn correct tray position in mouth resulting in under
extended impressionextended impression
PressurePressure
VoidsVoids

Final Impression with Border Outline LandmarksFinal Impression with Border Outline Landmarks
A,labial frenum ; B ,labial flangeA,labial frenum ; B ,labial flange
C, buccal frenum ; D,buccal flangeC, buccal frenum ; D,buccal flange
E, masster groove; F, retromoalarE, masster groove; F, retromoalar
padpad
G,Ling.frenum ; H, PremylohyoidG,Ling.frenum ; H, Premylohyoid
eminence.eminence.
I,retromylohyoid eminenceI,retromylohyoid eminence
AA
CC
BB
DD
EEFF
GG
HH
II

Step 1. With a sharp knife vertically score the castStep 1. With a sharp knife vertically score the cast
to a depth of 1.5 mm along the vibrating line.to a depth of 1.5 mm along the vibrating line.
Step 2. Score the anterior border of the posterior palatalStep 2. Score the anterior border of the posterior palatal
seal area to depth of 1 mm.seal area to depth of 1 mm.
Step 3. From step 1 bevel the cast posteriorlyStep 3. From step 1 bevel the cast posteriorly
to step 1 to a depth of 1.5 mmto step 1 to a depth of 1.5 mm
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The EndThe End
Scoring the master cast at the posterior palatal sealat the posterior palatal seal

Impression c d

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Impression c d