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Impression techniques inImpression techniques in
maxillofacialmaxillofacial
prostheticsprosthetics
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

INTRODUCTION
REHABILITATION
CONGENITAL ACQUIRED
CORRECTIVE/
PLASTIC SURGERY
PROSTHETIC
RESTORATION
MAXILLO FACIAL DEFECTS

PROSTHETIC RESTORATION
DIGITIZING IMAGING
TECHNOLOGY
CONVENTIONAL
TECHNIQUE
COMPUTERIZED TOMOGRAPHY
MAGNETIC RESONANCE
IMAGING
FLASH
DESS
LASER DIGITIZING WITH
CAD /CAM
RAPID PROTOTYPINGwww.indiandentalacademy.comwww.indiandentalacademy.com

Maxillofacial prosthesis
Tissue
retained
MP
IMPLANT
retained
MP
TOOTH
RETAINED
MP
IMPLANT /
TISSUE
RETAINED
MPCranial ,
Auricular ,
Orbital ,
Nasal,
Nasal septum,
Ocular
Prosthesis .
Auricular ,
Orbital,
Facial
Obturator ,
Mandibular
Resection ,
Craniofacial
Prosthesis
Auricular,
Facial
Prosthesis
(SUPPORT )
JPD 2OO5

ANCILLARY PROSTHESIS
FEEDING AID
SPLINT
COMMISURE SPLINT
FLUORDE GEL CARRIER
RADIATION CONE LOCATOR
RADIATION CARRIERwww.indiandentalacademy.comwww.indiandentalacademy.com

MISCELLANEOUSMISCELLANEOUS
LIP & CHEEK SUPPORT PROSTHESIS
LARYNGECTOMY AIDS
TRACHEOSTOMY OBTURATOR
TONGUE PROSTHESIS
ESOPHAGUS PROSTHESIS
POST MASTECTOMY BREAST PROSTHESIS
VAGINAL RADIATION CARRIERS.
BURNS STENTS
TRISMUS APPLIANCES

IMPORTANCE OF
PASSAVANT’S RIDGE
PALATO PHARYNGEUS
MUSCLE
M. MEMBRANE
PHARYNX
SUPERIOR
CONSTRICTOR
SPHINCTER
FIBRES
CONSTITUTE
PASSAVANT,S
MUSCLE
CONTRACTION
RAISES A
RIDGE ON
POSTERIOR WALL
OF PHARYNX

PASSAVANT,S
MUSCLE
AIDS IN CLOSURE OF
PHARYGEAL ISTHMUS.
BEST DEVELOPED IN
CLEFT PALATE Pt
COMPENSATES TO
SOME EXTENT FOR
DEFECIENCY

CLEFT PALATE
7 TO 12 TH WEEK OF I .U LIFE
COMPLETE FUSION OF PALATAL SHELVES
IN MIDLINE
POSITIONAL CHANGE IN PALATAL SHELVES
FROM VERTICAL TO HORIZONTAL POSITION
DEFECT
CLEFT PALATEwww.indiandentalacademy.comwww.indiandentalacademy.com

LOSS OF PALATAL CONTINUITY
LEADS TO
INABILITY TO DEVELOP & SUSTAIN ADEQUATE
ORAL PRESSURE
ERRORS IN CONSANANT ARTICULATION
NASAL EMISSION
HYPERNASALITY
HOARSENESS

Classification of cleft palate
ClassI ----involves soft palate alone.
Class II ---involves soft palate &
the hard palate in the midline .
classIII --- involves soft palate &
the hard palate & continues
through the alveolus on one side
of the premaxillary region .
class IV-- involves soft palate &
the hard palate & continues
through the alveolus on both sides
leaving a free premaxilla between


Class II Defect

CLASS III defect

Class IV Defect

Hinge
Obturator
Fixed
obturator
Meatus
obturator

TREATMENT PLAN
FOR
CLEFT PALATE PATIENT
EFFECT OF REPAIR ON MID FACIAL GROWTH ,
SPEECH& OCCLUSION
INFLUENCES THE
TIMING OF REPAIR
IDEAL TIMING OF REPAIR : 1- 1 ½ YEAR

IDEAL TREATMENT OPTION
FOR CLEFT PALATE & PALATO
PHARYNGEAL INADEQUACIES
TWO APPROACHES , SURGICAL &PROSTHETIC, ARE
USUALLY CONSIDERED
CERTAIN CIRCUMSTANCES LIKE
AGE MEDICAL
CONDITION
EXTENT OF
INVOLVEMENT
SURGERY NOT
IDEAL
PROSTHETIC
MANAGMENT
IDEAL CHOICE

Prosthetic treatment
Impression for complete denture obturator
Always advisable to obtain preliminary impression
in alginate material .
Metal Tray ---3 to 4 mm of space separates the tray
from the tissue in all areas .
Soft utility wax should be placed on the tray
So that most of the impression
Mat confined to the mucosal
bearing area

When the tray is filled
The material is under loaded in the
Cleft area .
Mainly in unrepaired clefts ,
& perforations
(may occur in class II& III
Perforations 1-3 mm ------guaze patch –( 1cm sq ).

Wax damming using utility wax

Peripheral seal
classII ---start with buccal seal from the frenum
along the right side of the denture
Contuined throu the right hamular notch
running medially at the post dam area
(until it reaches 3-5 mm from the cleft edge)
Turns forward & runs along the 3-5mm
from the cleft edge turn across the anterior
limit of the cleft run back along the opposite
Edge .

Buccal seal
(from
Frenum)
Hamular notch
Medially at the
Post dam area
Turns forward & runs along
The 3-5 mm from the cleft edge
Turn across the anterior limit
Of the cleft , runs back
Opposite edge
Post dam area
Hamular notch
Buccal periphery
Anterior
frenum

Class II defect

For class III & IV
Separate peripheral seal must be
created on side of the cleft &
Another on the other side .
According to principles of retention
Larger the tissue area remaining the
greater the chance of success .
Width of the cleft per se is not important ;
1cm wide cleft in small arch – little tissue remaining ,
whereas same cleft in a large arch –good deal of
mucosal area to cover .

Class III defect

IMPORTANCE OF PALATAL PLANE
IN OBTURATOR POSITION
IN ALL AGE GROUPS MID POINT OF PALATO
PHARYNGEAL CLOSURE ABOVE THE LEVEL OF
PLANE, ( EXCEPT 4-8 YR OF AGE BELOW THE LEVEL)
PHARYNGEAL OBTURATOR OBOVE THE PLANE
IN THE REGION OF GREATEST MUSCLE ACTIVITY
SERVE BEST AS
AID IN
SPEECHwww.indiandentalacademy.comwww.indiandentalacademy.com

Young patient Adult patient

Positional Consideration regarding
fabrication of obturator for cleft palate patients
Placement of middle third of the obturator
At the level of atlas vertebrae
Area of greatest constriction of the
Nasopharyngeal part
Obturator at this location requires less compensation
by the lateral Pharyngeal musculature than does
lower in the oropharynx

In 1959
Aram & subtenly
Reported the results of a study of normal
velopharyngeal function undertaken to acquire
Information relative to the positioning of a
Prosthetic pharyngeal extension
Concluded that
Level of palatopharyngeal closure varied
with increasing age
Palatal plane level as a reference source for closure
was reported to be more reliable than the atlas tubercle

WHEN PATIENT MANIFESTS
PALATAL INCOMPETENCE
POSSIBLE ALTERNATIVES
MUSCLE
TRAINING BY
SPEECH
PATHOLOGIST
PHARYNGEAL
EXTENSION
PROSTHESES

CONGENTIAL INSUFFIECENCY OF PALATO
PHARYNGEAL CLOSURE

PALATAL
LIFT PROSTHESIS

MUSCLE STIMULATION
MECHANISM
INCREASED SENSORY
STIMULATION
FACILITATE
MOTOR
ACTIVITY
OBTURATOR
PROGRAM
INCREASE
TACTILE STIMULATION
OF
LATERAL &POSTERIOR
WALLS

Rational for Pharyngeal obturator design
Light in weight &
Minimal bulk
Hygienic
Optimal size & function
Without impingement
on resting tissues
Noninterference in mastication ,
Swallowing , tongue function
During speech
Easily revised ,
repaired ,
/ remade

Fabrication techniques for
palatopharyngeal obturator
In the fabrication of the palatal section of the
parent prosthesis a wire / cast metal supporting loop /
grid is incorporated & directed along the palate
about a third to half posterior border of the hard palate to the
posterior pharyngeal wall
A core of modeling compound is added to extension &
gradually Increase in size & shape until it approximates
the cleft defect distal to the hard palate

Peripheral extension recorded
With modeling compound

Exaggerated gag reflex
Slower staged procedure is necessary
As warm bulk is added past the soft palate
in the pharyngeal region
Patient instructed to bend the head forward slowly
touch the chest & then to move it back ward again as in
nodding .

In addition direction is given to bring the head down &
forward , after which side to side rotation is employed
These movements helps in delineate
the posterior extension of the obturator
By displacing the warm compound to create a clearance
For the tubercular prominence
in the posterior pharyngeal wall

Establishment of Posterior extension
Lateral bulk is added to the core
Patient instruct to
Ah / phonate /
Repeatedly &
forcefully
Active movement of the lateral pharyngeal
musculature toward midline & superiorly
necessitates more vertical height to the impression
in order to Maintain border seal
Lateral indentation are made on the core to register this activity

If Lateral structures easily displaced
Low fusing compound may be used
Positive contact of the obturator on the resting border tissues is
Contraindicated
Superior height is determined by
Patient speech,
Clinical judgments of hyper nasality / hyponaslity
Vowel sounds / sibilants Aid in the assessment of
Palatopharyngel competence

Refinement in the compound obturator are made in response
to the performance by the patients.
On nearing acceptance of speech , deglutition , & comfort,
functionally molded impression arbitrarily reduced 1- 2 mm
Covered with mouth temperature wax .
After a uniform thickness wax has been brushed on the
compound core ,Tempered impression is placed in the mouth
Patient instruct to perform head movements

At the conclusion of the impression is examined & addition /
Corrections are made until it is acceptable for speech & comfort .
Alternate materials
Used for final impression medium
Waxes Plaster preparation

Impression technique mainly used for
Palatopharyngeal competence
In pt’s with unrepaired cleft palate
Insufficiently repaired nonfunctional
Soft Palate
Repaired nonfunctional palate
untreated short soft palate
submucous cleft

Impression technique for
acquired oral & paraoral defects
Treatment planning
Mouth preparation
Active phase of clinical
prosthodontic treatment

Preliminary impression
Well trimmed stock perforated metal trays
Fabrication of custom trays
Tray handle considerations
Rigid Necessary for tray
Manipulation
Non obstructive

Trays should be constructed over a wax shim of
sufficient thickness
To provide adequate space for
the impression materials
To leave a portion of the shim in the tray to act as a
stop while molding the impression .
Effective border seal in the border molding stage is difficult
Bec’z of the superior base in the defect itself

Width of the seal &
Tissue contact area
Depends upon the
Amount of functional movement
On the border tissues at the
Prostheses interface &
Displaceability of the tissue
being recorded in the
Impression
Contact area generally will be more extensive in the
lateral region / the cheek .
.

Thickness of the molding material will depend on
the amount needed To provide the desired facial
support .
It is not possible to make this determination acceptable
In a one step impression technique
Detail is not important in the obturator impression ,but
Accuracy is essential in recording the teeth & soft tissue
surface of the residual normal structures .
Consequently mouth temperature wax is acceptable &
Fully advantageous in altered casting technique for obturator
Development

It is thus possible to insert & remove the
Cast frame , making additions / deletions of the
impression material
dictated by
Function of the border tissues
The completed obturator impression has the extension
& configuration desired in the final prostheses &
Obviates the need for numerous / major adjustments
in the post insertion period .

Impression technique for
acquired defects of the mandible
Irreversible hydrocolloids
With an
Altered stock trays
(in relation to lingual
sulcus on the nondefect
Side )
To obtain preliminary impression
With maximum extension &
Tissue coverage

Special attention in relation to
Soft tissue areas
posterior to the resection
Disposable syringe is often used to inject
Impression materials into areas of difficult
Access prior to seating the stock tray
Master impression trays are fabricated
Conventional border molding with modeling plastic to
Establish peripheral extension
Which are refined with an elastic impression materialwww.indiandentalacademy.comwww.indiandentalacademy.com

Prosthesis retention in the mandible
Achieved by
Close adaptation Extending the lingual periphery
on the unresected side to the
maximal extent compatible
with the anatomic &
functional limitations
Considerations regarding the polished surface
Especially on the lingual surface of the resected &
unresected sides

Accurately recorded polished surfaces may aid in
Tongue will retain the mandibular denture in position more
Efficiently during function
Support for the
Mandibular prosthesis
Buccal shelf Crest of the ridge
Retro molar pad
Soft tissue bed posterior
to the bony resection

Buccal shelf on the unresected
Side Prime support area
Lingual inclination
Rotation of the mandible
Stability of the prostheses
Appropriately Contoured
lingual flange
On the unresected side
Tongue surface of the lingual flange resists the
lateral dislodging forces Developed during closure

Lingual flange on the resected side
Minor importance to the dislodging forces
Bec’z lateral forces exerted on the prostheses
During mastication primarily towards the unresected
side
Lower lip on the resected side is often retracted posteriorly
Cheek/ lip biting
Predisposing to

If the lower lip repositioned labially with the denture flange
This frustrating & disconcerting side effect can be negated.
Proper support for the lower lip will also enhance
control salivary secretions.
If the lip & cheek on the resected side heavily scarred
& unyielding
This extension can create a dislodging force upon the
Prostheses
Consequently , this flange must be carefully molded to obtain
Appropriate lip support without compromising retention

Clinician can record the polished surfaces
When molding the
master impression /
During try in stage
Peripheral seal of the maxillary denture difficult to achieve
In some patients .
Bec;z of the deviation of the mandible ,
anterior border of the ramus
& the coronoid process may be in close apposition
To tuberosity on the nonresected side

Making a functional impression
of the polished surface
Of the mandibular prostheses
Advocated by
FISH , LOTT,
LEVIN , BERESIN
SCHEISSER
This concept special application
For mandibulectomy patients
To enhance the stability & retention of the prostheses .

Altered cast impressions
After the partial denture casting has been fabricated ,
Verified , & adjusted , an altered cast impression is
Obtained of the edentulous areas .
Particular attention should be paid to the lingual extension
on the unresected side ,
especially polished surface.
Provides additional retention & stability for
the prosthesis .

Attempts to be made to extend the impression into
Soft tissue areas on the resected side .
If the partial denture is extended beyond the
bony resection ,
Teeth may be placed on the resected side
Improving the esthetics & enabling bilateral occlusal
contacts

In molding this segment of the prosthesis ,
Clinician should manipulate the cheek & direct the patient
to protrude & move the tongue from side to side.
The extension beyond the bony resection
Out rigger
Often a slight space will exist under this extension
when the tissues are at rest , but during function the
tissues will be in contact with these surfaces .

Extra oral prostheses

Extra oral impression technique
The art of obtaining a facial impression in preparing
a working model / moulage is essential to a well fitting ,
well fabricated facial prosthesis .
Materials vary according to the end result desired .
If greater accuracy is needed
Reversible hydrocolloid /
plaster of Paris .

Needs goods details quickly
Silicone / irreversible
hydrocolloid.
General contour
(But not very much
Details )
Orthopedic plaster
Bands /
Impression compound
Can be used to form
Lead radiation protection shield

Patient Preparation before facial impression
Position of the
Patient
Should be either reclined in the dental
chair /
better lying on a table with his head
slightly elevated .
Achieves relaxed muscle tone
of the Patient

NOSTRILS—BLOCKED OUT ,
AIR WAY MAINTAINENCE ,
WAX STRIP—BOXING

REVERSIBLE HYDRO COLLOID
APPLICATION
WITH BRUSHwww.indiandentalacademy.com

Preparation of the patient
Materials
Irreversible
Hydrocolloid
Variations from intra oral usage
ratio of powder to water is different .
Every scoop of powder , 1 ½ to 2 parts
of cool water should be used .
Enables to flow readily into all undercuts
It is not applied with brush

Plaster of Paris
This age old material gives excellent accuracy of slight
facial defects .
(ex ;in moulages before & after orthodontic treatment )
It is not to be used
When the defect is fresh, bleeding/
Large or where deep undercuts
exists & need to be reproduced .
Glycerin --- separating media is used before pouring
the model

Orthodontic plaster band
The pieces are cut to the width of the face while
they are still dry.
For whole face -----------six pieces overlapped
are necessary.
Main purpose ---for fabrication of radiation protector
shield .

Ocular prostheses
Impression
2 methods of fitting the prosthesis into socket
To make the scleral pattern’
---from the stainless ball
Bearing
(Dr. Victor Dietz )
To make an impression
of the contents of the
Enucleated socket
With alginate
Finished prosthesis is
Heavier .Drooping of the lower lid
Cause

It is important for the surgeon to place a conformer
In the socket after enucleation .
Most generally done at the time of surgery ;only exception
-----unusual amount of hemorrhage occurs.
The conformer ----made of clear acrylic ,
must be large enough to support the lids .
A horizontal measurement of
The eye socket Determines
Size of the ball bearing
To be selected

Impression mat ---
irreversible hydrocolloid
Impression tray
---hard base plate wax .
Tissue side scored with hot spatula
--to afford retention for the
impression material ,
Patient position
-- seated erect position
requested to stare at a distant
spot .

instruct to hold his gaze in straightforward
position with Eyes open
Procedure ensure that the
Posterior aspect of the enucleated socket ,
&
Rectus muscle will be in same relative position
As those of the remaining eye
With the patient’s eye , injected into the socket
careful to completely the fill
socket without trapping
tiny air pocket .

Tray coated with impression mat placed over the eye
when set, material in the socket & over the lids
can be removed as one piece .
patient instruct to open his eye as wide as possible ,
Care must be taken not to tear the impression from the tray
at the thin section
Represent
Lid opening

Orbital defects
Impression
To record the orbital & periorbital tissues
Bed.
Patient position ---upright
extreme care should be taken not to
displace the tissue bed .
During procedure ---
patient should keep remaining
eye open & fixed to distant point .
To prevent the undesirable contraction
Of the residual lid musculature &
Prevent distortion of the defect .www.indiandentalacademy.comwww.indiandentalacademy.com

Cast fabricated in dental stone
A hole should be drilled through the posterior orbital wall
To facilitate the
Movement & adjustment of the ocular portion
Of the prosthesis

Auricular prosthesis
Impression of the
Defective side
Patient
Position
Defective ear
facing up
External auditory
Meatus ----blocked with wet gauze .
Impression mat
reversible hydrocolloid
Paper clips –reinforcement ,
Plaster Paris –backing .
Impression of the
Nature side

Auricular prosthesis
Impressions Unlike orbital defects ,tissue beds in the
auricular area are not displaceable ,
Distortions do not results from postural
Changes
Impression can be obtained pt lying on his side
In a supine position .
Condylar movements closely examined ,
Results in
Tissue bed mobility

Tissue bed mobility
Can affect the
Margin placement ,
Tissue coverage ,
Retention of the prosthesis .
Impression materials –reversible hydrocolloid,
rubber base impression material.

Definitive nasal prosthesis
As in orbital defects , postural changes may result in
distortions of the tissue bed .
For master impression ----patient should be in
upright position
Elastomeric impression materials ideal for this task
A facial moulage is made , using the preliminary cast
a master impression tray is fabricated confined
to the defect

Advanced technology
In
Extra oral prosthesis

NOVEL APPROACHES TONOVEL APPROACHES TO
PROSTHESIS PRODUCTIONPROSTHESIS PRODUCTION
 LASER SURFACE DIGITIZERLASER SURFACE DIGITIZER
 PROBLEMS ASSOCIATED WITH LASER SURFACEPROBLEMS ASSOCIATED WITH LASER SURFACE
DIGITIZERDIGITIZER
 DIFFERENT TYPES OF LASER DIGITIZERDIFFERENT TYPES OF LASER DIGITIZER
ATOS
FAST SCAN
VIVID 700
FASCIA

INTEGRATION OF LASER SURFACE
DIGITIZING
WITH CAD/CAM
INTEGRATION OF LASER SURFACE
DIGITIZING WITH CAD/ CAM
LASER SURFACE DIGITIZER
SURFACE PATCHING
POINT CLOUD DATA
CROSS SECTIONING 3 D CURVE GENERATINGwww.indiandentalacademy.comwww.indiandentalacademy.com

MIRROR IMAGED
CAD MODEL
FULLY PATCHED
CAD MODEL
POSITIONING & FITTING OF
PROSTHESES

RAPID PROTOTYPING
DIFFERENT TYPES OF RAPID PROTYPING TECHNIQUE
STERIO
LITHOGRAPHY
SELECTIVE
LASER
SINTERING
LAMINATED
OBJECT
MANUFACTURING
SOLID
GROUND
CURING

Rapid prototyping process
Gluing
Chemical
Sintering
LOM
3 DP
PHOTO
CURING
DEPOSITION
SLA
SGC
FDM
BPM
SLS
FDM

PROCESS CHAINS OF NEWPROCESS CHAINS OF NEW
INTEGRATED MANUFACTURINGINTEGRATED MANUFACTURING
SYSTEMSYSTEM
MEDICAL IMAGING
CT
MRI
LASER DIGITIZING
POINT CLOUD
DATA
2 D SLICE DATA
3 D
RECONSTRUCTION
C
D
M
O
D
E
L
CAD MODELLING
DATA
A
C
Q
U
I
S
T
I
O
N

CAD MODELLING
DESIGN OF NEGATIVE MOLD
RP FABRICATION OF MOLD
CASTING
RP MASTER PATTERN
FABRICATION
ACTUAL PROSTHESIS
STL MODEL PROSTHESIS MODEL

Conclusion
There are many individual presentation&
varying challenges in supplying patients with prostheses
for palatopharyngeal defects & the restorative dentist
has to be imaginative & innovative .
As for any other successful treatment , the important
Feature is to be aware of the principles & to stick with them

References
( Books)
Text book of maxillofacial
prosthesis
VAROUJAN CHALIAN
Text book of maxillofacial
Prosthetics
WILLIAM R. LANEY
Complete denture
prosthodontics
John J Sharry
Maxillofacial
Rehabilitation
Beumer

References
(Journal )
Int J prosthodont
2oo2 ;15 :129 -132
Optical data acquisition
For CAD design of
Facial prosthesis
Int J prosthodont
2003;16:543-548
Integration of laser digitizer
WITH CAD/ CAM
Dental update
2002 ;29 :482 -486
Can Rp ever become
A routine feature in
GDP
Int J prosthodont
2003;16:326-328
Computer aided
MFP
J.Prosthet .Dent
1976 ;35:321 -326
Prosthodontic aspects of
Palatal elevation &
Palatopharyngeal stimulation
Dental update
2005 ;32 :277-285
Obturators for palatal defects

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