theories of impression making in complete denture
TRANSCRIPT
THEORIES OF IMPRESSION MAKING
AND IMPRESSION PROCEDURE FOR COMPLETE
DENTURE
Dr. Dipal Mawani1
CONTENTSHistory
Definitions
Biologic Considerations For Maxillary Impressions
Biologic Considerations of Mandibular Impressions
Principles of Impression Making
Classification of Impressions
Impression Procedures
Impression Techniques in Compromised Situations
Review of literature
Conclusion
References2
3
“Ideal impression must be in the mind of the dentist before it is in his hand. He must literally make the impression rather
than take it”
- M.M. De Van
History
1728: Pierre Fauchard made dentures by measuring the mouth with compasses and cutting bone into an approximate shape.
1845-1899: Concepts of atmospheric pressure, maximum extension ofdenture bearing area, equal distribution of pressure and close adaptation ofthe denture bearing tissues were stressed.
1886 – Richardson mentioned about making plaster impressions of tissuesat rest & achieving adhesion by contact
1896: Greene brothers introduced Muco-compressive theory.
1900-1929: Concepts like Rebase impressions, border molding, posterior palatal seal and techniques for flabby tissues were introduced.
4
1930-1940: This era recognized the anatomy of the denture bearing areas and muscle physiology was related to impression procedures. This is evident by descriptions of border molding & concept of special trays.
1946: Page gave the concept of mucostatics
1951: Boucher introduced selective pressure theory.
1965-1980: Techniques to manage compromised situations were introduced
5
6
COMPLETE DENTURE IMPRESSION :-
a complete denture impression is a negative
registration of the entire denture bearing,
stabilizing and border seal areas present in the
edentulous mouth. (GPT-9)
PRELIMINARY IMPRESSION :-
a negative likeness made for the purpose of diagnosis, treatment planning, and/or the
fabrication of a custom impression tray preload . (GPT-9)
BORDER MOLDING :-the shaping of impression material along the border areas of an
impression tray by functional or manual manipulation of the soft tissue
adjacent to the borders to duplicate the contour and size of the
vestibule (GPT-9)
IMPRESSION MATERIAL :-
any substance or combination of substances used for making an
impression or negative reproduction (GPT 9)
7
Limiting and supporting structures of maxillary denture bearing area
8
Maxillary stress bearing and relief areas
Primary
Hard palate on either side of
raphae
Firm tuberosity
9
Secondary
Rugae area
Crest of Residual Alveolar Ridge
Relief
Incisive Foramen
Mid Palatine Raphae
Palatal Tori
Sharp Spiny Processes
Limiting and Supporting areas of mandibular denture bearing area
10
Mandibular Stress bearing and Relief areas
11
Primary
Buccal Shelf Area
Retromolar Pad
Secondary slopes of
Residual Alveolar Ridge
Relief
Mandibular Tori
Mental Foramen
Genial Tubercles
Prominent Retromylohyoid Ridge
To achieve a successful impression, the following concepts should be adhered to, irrespective of the selected technique:
1. The impression should extend to include the entire basal seat.
2. The border must be in harmony with the anatomical and physiological limitations of the structures.
3. Physiological type of border moulding procedure performed (dentist /patient under the guidance of the dentist).
4. Space for the final impression material within the impression tray.
12
5. Selective pressure on the basal seat during impression making.
6. The impression must be removed without damage to mucous membrane
7. A guiding mechanism is provided for correct positioning of the tray.
8. Tray and impression material should be dimensionally stable.
9. External shape is similar to external form of the complete denture.
13
Principles of
Impression Making
Support
Retention
StabilityEsthetics
Preservation of alveolar
ridges
14
Retention
• that quality inherent in the dental prosthesis acting to resist the forces of
dislodgment along the path of placement (GPT-9)
• It is the quality inherent in the prosthesis which resists forces of gravity,
adhesiveness of food and forces associated with opening of mouth
15
Physical Factors
affecting Retention
Adhesion
Cohesion
Gravity
Interfacial Surface Tension
Capillary Attraction
Atmospheric Pressure & Peripheral
Seal
16
Adhesion :-
• Physical attraction of unlike molecules
• It acts when saliva sticks to the denture base & to the mucous membrane of basal seat .
17
Cohesion:-
the act or state of sticking together tightly (GPT-9)
• Physical attraction of like molecules for each other
• Occurs within the layer of fluid (usually saliva ) present between the denture base & the mucosa.
• Effective – layer should be thin
18
Interfacial surface tension:-
• Resistance to separation by the film of liquid between the denture
base & the supporting tissues .
• Dependent on the ability of the fluid to wet the rigid
surrounding material .
19
Mucostatics dismiss adhesion and cohesion as factors in retention,
the entire phenomenon being attributed to interfacial surface
tension.
But it has been proved that if it was not for the forces of adhesion
and cohesion, the forces of interfacial surface tension wont exist.
Attachment of a denture is possible because both tissue and denture
base material can become wet which means its molecule will adhere
to water molecules.
Basic principles in impression making
J Prosthet Dent 2005;93:503-8.20
Atmospheric pressure:-
• Acts to resist dislodging forces applied to the denture, if dentures have an effective seal
around their borders i.e. Peripheral Seal. (14.7lb/in2)
• Retention due to atmospheric pressure is directly proportional to the area covered by
the denture base.
21
Anatomical Factors involved in Retention
• Maxilla – PPS, Retro zygomatic space
• Mandible – Pear shaped pad, Retro Mylohyoid Space
22
Mechanical Factors involved in Retention
• Undercuts
• Rubber Suction Discs
• Magnets
• Suction Chambers
23
Stability
the quality of a complete or removable partial denture to be firm,
steady, or constant, to resist displacement by functional horizontal
or rotational stresses (GPT-9)
24
Support
the foundation area on which a dental prosthesis rests;
“the resistance to forces directed toward the basal tissue or underlying
structures” (GPT-9)
Esthetics
Role of esthetics in impression making refers to the development of the
labial and buccal borders, so that they are not only retentive but also
support the lips properly.
25
Preservation of the alveolar ridges
DeVan (1952) stated that “the preservation of that which remains is of utmost importance and not the meticulous replacement of that which has been lost”
• Stress-bearing areas and non-stress bearing areas should be recorded under stress and relief respectively.
• Peripheral tissues to be recorded without over extensions.
• Wide tissue coverage
26
Classification
Depending on the theories of
impression making
Muco-compressive
Muco-static
Selective pressure
Depending on the technique
Open Mouth
Closed Mouth
Depending on the purpose
of the impression
Diagnostic
Primary
Secondary27
Definite pressure technique/ Muco-compressive
• Introduced by Greene brothers
• The tissues recorded under functional pressure provide better support and
retention for the denture.
• Many advocate the use of closed-mouth impression techniques.
• Advocates of this theory believe that occlusal loading during impression
making is comparable to the occlusal loading during function.
28
• Primary impression made with impression compound
• Special tray made using shellac base plate. And its periphery are 1/8th inch shorter than denture outline.
• Second Impression is made in the special tray using compound
• Bite rims with uniform occlusal surfaces are then made.
• Areas to be relieved are softened and the impression is inserted in mouth and held under biting pressure for one or two minutes
• Borders are molded by asking the patient to perform functional movements
• The PPS was obtained by making the patient swallow, under biting pressure.
29
Advantages
• Better retention and support during functional movements
• Provide more tissue coverage
Disadvantages
• The pressure applied can overstress the tissues.
• This often resulted in good initial retention but eventual bone resorption and loose dentures.
• Loss of retention during rest due to tissue rebound.
30
Minimal pressure theory/ Mucostatic:-
• Described by Addison, 1944 who attributed it to Henry L. Page.
• He applied Pascal’s Law to soft tissues “Any pressure applied to aconfined fluid is transmitted undiminished in all directions”.
• Mucosa being more than 80% water, will react like a liquid in a closedvessel & cannot be compressed.
• The impression material should record, without distortion, every detail ofthe mucosa denture would fit all minute elevations & depressions.
31
• Demanded that a metal base be used instead of acrylics
• This theory has regarded interfacial surface tension as the only important
retentive mechanism.
• Did not use conventional flanges (did not resist vertical displacement).
• Dykins (1947) recommended a short lingual flange to resist lateral
displacement.
32
• High regards for the tissue health and preservation
• Good stability due to close adaptation of denture bases
• Less tissue coverage
• Reduced retention
• Lack of border-moulding reduces effective border seal
• Lack of border seal permits food lodgment
• Compromised aesthetics due to short denture flanges
• Tissue variations at the time of impression making and insertion may affect the results.
33
Advantages Disadvantages
Selective Pressure Technique (Boucher):-
• Principle – mucosa over the ridge is best able to withstand pressure
mucosa covering midline is thin and has little submucosal
tissue.
• Forces acting on the denture confined to the stress-bearing areas.
• Non stress-bearing areas are relieved and the stress-bearing areas are
allowed to come in contact with the tray.
34
Disadvantages of selective pressure technique
•Demands firm, healthy mucosal covering over the ridge.
Hence, it cannot be used in flabby ridges
35
MUCOSEAL TECHNIQUE :-
• Stated by Pryor, 1948
• Introduced as a variation to mucostatic technique
• Anterior lingual border molded by the floor of the mouth with the tongue in repose
• Tray extended horizontally backward, over sublingual glands towards the tongue to achieve a border seal
• Benefit of minimal pressure, provides maximum extension of denture borders & maximum denture bearing area coverage.
36
Impression by the use of subatmospheric pressure– Milo V. Kubalek, Bert C. Buffington (1966)
• The objective of this technique is to reduce the stress onany given tissue by increasing the load bearing area.
• To realize the idea, the form of tissues must be recordedboth vertically and laterally so that all surfaces can bear anequal load and vacustatic technique is an attempt toachieve this.
• When a controlled partial vacuum is established, animpression tray specially built for the patient is maintainedin the mouth without direct mechanical support of anykind.
• The difference between subatmospheric pressure withinthe tray and atmospheric pressure outside is all thatretained the impression in a static position.
• It denotes the equilibrium of forces which results when acontrolled vacuum is established.
37
38
Open mouth impressions:-
• Made with a tray that is held by the dentist.
39
Advantages
Visualization of the muscle trimming
Various movements can be accomplished easily.
Denture retention can be predicted in open as well as in
closed mouth movements.
Pressure or pressure-less technique can be employed by
using this technique.
Closed mouth impressions:-
• Supporting tissues are recorded in functional relationship.
• Requires wax occlusal rims.
40
• Interferences of tray handles
and operator’s finger is
eliminated.
• Time saving -- Border molding, final impression, jaw relation (tentative/final) can be completed in 1 time.
• Rebound of the tissues during rest leads
to denture displacement.
• Tendency for over-extension or under-
extension
• Fatiguing to the dentist and patient.
• A constant pressure is exerted over
tissues, hence blood supply is
compromised leading to ridge
resorption.
41
Advantages Disadvantages
• Hand manipulation
The contour of the denture borders may be obtained by the dentist with the use of manual manipulation of the lips and cheeks within functional limits. Patient’s tongue movements record the lingual borders.
• Functional movements
The denture border may also be formed by having the patient make “functional” or “physiological” movements such as sucking, grinning, licking, swallowing etc.
42
Depending on Manipulation :-
(1) Diagnostic Impression :-
• The negative replica of the oral tissues used to prepare a diagnostic cast.
• Used for study purposes like measuring the undercuts, locating the path
of insertion.
• Is made as a part of treatment plan and to estimate the amount of pre-
prosthetic surgery required.
• Can be used for tentative jaw relation and to evaluate the inter-arch
space. 43
Depending on the purpose of the impression
(2) Primary Impression :-
• An impression made for the purpose of construction of a special tray.
• There should be at least 6mm clearance between the stock tray and the
ridge for materials used in making primary impression.
(3) Secondary Impression:-
• Making the wash impression.
• Developing the posterior palatal seal.
44
(A) Selection of Impression material :-
• The material is selected according to the clinical findings,
availability, which in turn influences the technique as well
45
• The beginning of good impression starts with the selection ofthe correct stock tray.
(B) Selection of Impression tray :-
Selection of maxillary stock
Tray :-
• Width and height of the vestibular spaces
• Posteriorly - cover the Hamular notches & vibrating line
• Anteriorly - labial notch should coincide with labial frenum providing sufficient clearance for the impression material
• Tray under extended –
• Tuberosities
• Distobuccal areas.
46
Selection of mandibular
stock tray :-
• Posteriorly the tray should cover the retromolar pad
• Anteriorly should be centralized with labial frenum with adequate clearance
• Tray under extended –
• Retromolar pad or in
• Retromylohyoid fossae.
47
(C) Selection of impression technique :-
• Clinical findings
• Availability of the materials
• Experience of the dentist
• Patient related factors
48
Operator position for maxillary impression
Correct
49
Incorrect
Operator position for Mandibular Impression
50Correct Incorrec
t
Making the preliminary impression
Tray should be adjusted by bending
51
Selection of stock tray Position borders at
hammular notches
Lift the tray anteriorly, 3-5 mm space for
impression material
Border of the tray
should be cut if
required
Borders should be
smoothened
Material
Manipulation
(hot water bath
at 140F)
52
Placing the tray in the patients mouth.
Performing Movements to mold the material.
53
• Impression compound is softened in a hot water bath at 140°F.
• After kneading it is loaded on to the tray and shaped roughly to
the shape of the ridge with the fingers.
• The distolingual flange areas can be molded with fingers to
simulate the final impression.
54
Mandibular Impression
• The left posterior corner of the tray is inserted while retracting the right cheek with operator’s left hand and tray is rotated and centralized over the ridge.
55
• Patient is instructed to lift the tongue, and tray is seated while applying
pressure
• Light border molding movements are performed including tongue
movements.
• Compound is allowed to harden and chilled after removal impression is
inspected.
56
57
Different Techniques
Modified stock tray -
Type II impression compound Double
thickness or reinforced
shellac base plate
Sprinkle-on method for acrylic resin
traysFinger adaptation
Dough method for acrylic resin
trays
Vacuum-formed
thermoplastic resin trays
Visible light cure resin
trays
58
Special Tray :-
An individualized impression tray made from a cast recovered from a preliminary
impression. It is used in making a final impression (GPT 8 )
Depth of the sulcus is marked on the cast Borders are kept 2mm short
Lip and cheek are reflected and the
borders are observed
Over-extensions are
trimmed 59
Checking for tray extensions
60
Tray Inserted In the patient’s
mouthLip and cheek are reflected and the borders
are observed
Over-extensions are trimmed
61
Tongue is Protruded Lateral movements performed Over-extensions are trimmed ;
Borders are smoothened.
If tray displaces =
indicates contra-lateral
side over extension
If tray raises posteriorly
distolingual flange need
adjustment.
Border molding (Peripheral tracing , Muscle trimming)
• Border molding materials include:
• Modelling compound sticks (Green Stick)
• Polyether impression paste
• Tissue conditioners
• Auto polymerizing acrylic resin
• Impression waxes
62
Methods of border molding
Labial and Buccal borders
Smiling whistling grinning
63
(1) Functional method :-
Normal functional movements mold the borders in harmony with muscle action
Buccal frenum and Buccal
borders
Sucking
Lingual borders
Licking the lips and tongue movements
Lingual border and Floor of
mouth
Swallowing
Distobuccalborders
Opening, closing and side to side
movements
(2) Digital manipulation :-
• Dentist manipulates the lips and cheeks of the patient to simulate the influence of these on the denture borders.
• Easy ; does not require much of patient cooperation.
• Influenced by the direction of movement and the force applied.
(3) Combined :-
• Border molding is usually done by a combination of digital manipulation by the dentist and functional movements by the patients.
64
Steps in Sectional border molding
65
Softened compound added along dry
borders of required segment
Cheek outward, downward and
inward
Softened again with alcohol torch.
Tempered in warm water bath.
66
Labial Border Molding
outward, downward and inwardsMolding the Frenum
Compound placed on posterior border. Tray seated in mouth with firm pressure.
Compound placed on posterior border
71Compound added on buccal border
The tray gently seated in place.
The borders should be smooth,round
and symmetrical
Compound placed on labial border
72
Labial Border Molding
outward, upward and inward
Lingual Border Molding Movements
77
Secondary impression
The final impression material is mixed according to manufacturer’s directions and uniformly distributed within the tray.
78
79
Techniques of Impression making
80
One step border molding procedure (polyether) ( Boucher, JPD:1979:41:347 )
Dale E. Smith
81
Adhesive is applied on
the tray
Polyether loaded into a
plastic syringe with slightly less
catalyst
Material is syringed
around the borders & PPS area
Quickly pre-shaped to
proper contours with finger
moistened in cold water
Tray is inserted in the mouth
without material
distortion
Borders checked for
proper extensions
All movements carried out
quickly.
Remove tray when
material is set
Examine for accuracy
Deficient site corrected with a small mix of
polyether material added
to the area
Advantages :
• Numbers of insertion of the tray are reduced.
• Developing all borders simultaneously avoids propagation of errors caused by a mistake in one section affecting the border contours in another. 82
Impression using new silicone impression materials
I.Hayakawa, I Watanabe(2003)
• Convenient technique for making
impression using newer silicone
materials .
• Heavy bodied silicone material is
used for simultaneous molding of
all borders . (Exahiflex GC)
• Final wash impression is made
with light bodied silicone material
(Exadenture GC)
83
Tray 2mm short of tissue
Apply adhesive
Add silicone across border and PPS area
Examine borders ; trim excess material ; Deficient areas remolded
84
Advantages :
• Easy to perform
• Recommended for beginners
• Reduction in chair side time
• Silicone material – non irritating, minimal patient discomfort.
85
Impression techniques in compromised situations
86
Unsupported hyperplastic flabby ridges
Severely resorbed mandibular ridge.
Restricted access to oral cavity.
Unemployed Mandibular
Ridge.
Impression technique for patient with unsupported flabby ridges
87
HobkirkTechnique
Zafrulla Khan Technique
Jone.D. Walter Technique
Splint method by Allan
William.H.FillerTechnique
• The hypermobile tissues should be recorded without distortion with minimum displacement.
• Rest of the tissues are recorded with selective pressure technique.
88
Hobkirk technique:
• Single custom tray used.
• Border molding is done in the usual manner.
• Impression - heavy bodied addition silicone
89
Material overlying the hypermobile tissue is cut away and escape
holes made.
Wash impression - light bodied material.
90
Walter Technique: (BDJ 1964:117:392)
• Healthy tissues - zinc oxide eugenol paste
• Undisplaced fibrous tissue - impression plaster.
91
Zafurulla Khan Technique: -
92
Splint Technique by Allan Mack
• Exceptionally flabby tissues.
• Special tray made with heavy relief over the flabby area, plaster is mixed
and applied (3mm), allowed to set.
• Tray is filled with 2nd mix of plaster and the impression is made.
• The initial coating of the flabby areas thus acting as a ‘splint’ whilst the
impression is made and it gets removed along with the second
impression
93
Impression Technique For Severely Resorbed Mandibular Ridge
• Cases which lack of ideal amount of supporting structure.
• Encroachment of the surrounding mobile tissues on to the denture
border reduce both stability and retention.
• Thus the main aim of the impression procedure is to gain maximum
area of coverage with minimum pressure by obtaining a fairly long
retromylohyoid flange for a better border seal and retention.
94
Flange TechniqueDynamic Impression
Technique
Winkler’s Technique(Functional
Reline)Miller’s Technique
Mccold and Tyson Admixed Technique
95
Flange technique by Frank Lott and Bernard Levin(JPD 1966:16:394-413)
• Making impressions of the soft structures adjacent to the buccal, lingual labial
surfaces and incorporating the resulting extensions or flanges in denture.
• Fluid wax is rolled from the retromolar pad region to sublingual region, large
enough to restore the areas of estimated resorption.
• Patient is asked to forcefully perform functional movements to give a border
extensions which covers maximum surface area.
96
Dynamic impression method(G. Tryde, K.Olsson, Jenson)
Dislocating effect of the muscles on improperly formed denture
borders is avoided
Impression material : Irreversible hydrocolloid
• For this mandibular rests are made
on the occlusal aspect of lower record
base with thermoplastic material.
97
• Alginate is mixed and DIRECTLY APPLIED on tissues & then tray is placed
• When material is soft the patient is asked to close the jaw slowly.
• Impression material is shaped by muscular activity.
• Patient should swallow 3 to 4 times in the 10 seconds interval till the material in still moldable state .
98
• Winkler’s technique : -
He described closed mouth
impression technique which uses
tissue conditioners and the final
impression is made with a light body
elastomeric impression material
Miller’s Modification: -Uses mouth temperature waxes instead of tissue conditioners
99
• Complicated by folds of atrophic and/or non-keratinised tissue lying on the ridge
• Impression medium -- admix –
3 parts (red) impression compound
7 parts of greenstick (by weight)
• The working time of this admix is 1–2 minutes and this enables the clinician to mould the tissues to give good peripheral moulding
100
Flat mandibular ridge covered with atrophicmucosa : McCord and Tyson admixed technique
Fabrication of a sectional impression tray and sectional complete denture for a patient with microstomia and trismus: A clinical report (J Prosthet Dent 2003;89:540)
• Maxillary impression inserted into the patient’s mouth in 2 separate pieces: left and right.
• After placement, these pieces were stabilized by means of the acrylic resin block.
• Zinc-oxide eugenol impression.
101
•After the impression paste set, acrylic resin block detached from the
pins, right and the left pieces removed separately by fracturing the
impression material.
•The acrylic resin block was carefully fitted on the pins, and after it
was determined that the fracture line joined smoothly, and cast were
poured
102
Unemployed mandibular ridge
• Due to continuous ridge resorption in old denture wearers support of the denture becomes progressively transferred to peripheral parts of the denture bearing areas while the ridge takes less load. Thus the ridge is referred as unemployed.
• Technique:
103
Old
denture
New denture
• Primary impression - alginate and cast poured.
• Impression compound impression is taken of the cast.
• Periphery is trimmed.
• Green stick is applied to the periphery and placed in patients mouth to record borders with border molding.
• The compound over the ridge is then cut with a sharp knife.
• Record the working surface with impression paste under heavy digital pressure -- transfer as much of the load as possible to the peripheral parts of the denture bearing area.
104
105
Cocktail Impression Technique: A New Approach to Atwood’s Order VI Mandibular Ridge DeformityPraveen GJ Indian Prosthodont Soc (Jan-Mar 2011) 11(1):32–35
Custom tray with mandibularrests
Custom tray fits against maxillary alveolar ridge at an increased ht.
106
Patient performing functional movements
The final impression
Review of Literature
107
Diurnal variation in palatal tissue thickness –Stephens, Cox, Sharry (1966)
• In this study the variation in palatal thickness atdifferent time of the day is measured.
• A small micrometer was attached to an acrylic resinhood which straddled the upper arch and fitted theocclusal surface of the molar and premolar teeth, thiswas used to measure the diurnal changes in palataltissue.
• The results indicated that the palatal tissues werethickest when the subjects were lying in bed after a fullnight sleep and it starts to shrink in the morning andcontinues in the afternoon. Slight increase in tissuethickness is seen again in the evening.
108
CONCLUSION
The main objective of impression making is to fabricate
dentures having maximum retention and stability
without causing any damage to the supporting
structures. Thus the choice of impression technique and
material is made by the dentist on the basis of the oral
conditions, concepts of function of the tissues
surrounding the denture and ability to handle the
available impression material.
109
References :
• Zarb GA,Bolender CL,Prosthodontic treatment for edentulous patients- 12th
ed, 13th ed
• Rudd KD, Morrow RM, Dental laboratory procedures complete dentures Vol. l ,2nd ed
• Impression for complete dentures, Bernard Levin
• Complete denture prosthodontics, John J Sharry, 3rd ed
• Essentials of Complete Denture Prosthodontics, Winkler
• A colour atlas of overdentures and complete dentures
• Basic principles in impression making MM Devan J Prosthet Dent 2005;93:503-508
• Complete denture impressions J Prosthet Dent;1965:15(4):603-614
• Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete denture retention, stability, and support. Part I: retention. The Journal of prosthetic dentistry. 1983 Jan 1;49(1):5-15.
110
• Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete dentures. Part II: stability. The Journal of prosthetic dentistry. 1983 Feb 1;49(2):165-72.
• Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete dentures. Part III: support. The Journal of prosthetic dentistry. 1983 Mar 1;49(3):306-13.
• Management of the flabby ridge: using contemporary materials to solve an old problem,BDJ:2006:258:261
• Modified impression technique for hyperplastic alveolar ridges JPD:1971:25:609.
• Physiological determinants of primary impressions for complete dentures,JPD:1984:53:611
• A systematic review of impression technique for conventional complete denture J Indian Prosthodont Soc :10(2):105-111
• A critical analysis of mid century impression techniques for full dentures J ProsthetDent 1951; 472-491
• A critical analysis of complete denture impression procedures: contribution of early prosthodontists in India J Indian Prosthodont Soc ;11(3):172-182
• Impressions for complete dentures using new silicone impression materials Hayakawa, Watanabe; Quintessence International:34:3:177-180
• Fabrication of a sectional impression tray and sectional complete denture for a patient with microstomia and trismus: A clinical report; J Prosthet Dent 2003;89:540
111
THANK YOU
112