Impression procedures / implant dentistry course/ implant dentistry course

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Impressions for Complete
Denture.
Continuing Dental Education.
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

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Principles of Impression making.
• To cover the MAXIMUM possible
denture supporting AREA.
• To achieve the closest possible
CONTACT with the underlying
epithelium.
• To establish a PERIPHERAL SEAL.

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Operator position for maxillary
impression
• Correct Incorrect

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Operator position for Mandibular
Impression
Correct Incorrect

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Techniques.
• Open mouth
– Mucocompres
sive
– Mucostatic
– Selective
pressure
• Closed mouth.
•Single stage
•Double stage

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Conventional two stage
procedure.

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Primary impression
• It records the useful anatomy of the
edentulous mouth so that a model can be
cast on which an accurately fitting special
tray can be made.
Materials used:Alginate
Impression compound.

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Primary Impression in alginate.
4. Tray should be adjusted by
bending .
1.Selection of stock tray. 2. Position borders at hamular notches.
3. Lift the tray anteriorly, 3-5
mm space for impression
material. www.indiandentalacademy.com

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5. Border of ray should be
short of tissue reflection.
6. Adequate clearance in
frenal areas.
7. Tray should be
smoothened.

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10. Tissue stop in central
portion of tray.
8. Deficient borders corrected by
adding utility wax.
9. Tray extension in buccal space
and tissue side of posterior
border.

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11. Location of hamular notches. 12. Mark the vibrating line.
13. Some alginate to be
placed in vestibule.
14. Alginate to be placed
in deepest part of palate.www.indiandentalacademy.com

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15. Tray to be rotated into the
mouth and seated first at the
back of the mouth.
16. Upper lip elevated.
17. Tray is held in the mouth. 18. Labial and buccal borders
to be molded.www.indiandentalacademy.com

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19. Completed maxillary Primary Impression
with rounded and molded peripheries.

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Mandibular alginate impression.
3 . Tray should cover retromolar
pad and rest against external
oblique ridge.
1.Britania metal edentulous tray. 2. Retromolar pad should be
identified

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4. Bending and cutting the tray for adjustment.
5. Adding utility
was to extend
lingual border.

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7. Patient told to do tongue
movements.
6. Patient told to raise the
tongue and tray is rotated in
the mouth.
8. Gently mold the labial and buccal areas.www.indiandentalacademy.com

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• Completed Mandibular Primary Impression.

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Alginate impression in
compund tray.
3. Compound placed in
the tray.
1. Modelling compund. 2. Softenend in water
bath and kneaded.
Alternative Techique for primary impression

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5. Should cover mylohyoid ridge
and external oblique ridge.
4. Molded with fingers to
ridge form.
6. Gently warmed over a flame. 7. Before insertion, tempering
in warm water bath.www.indiandentalacademy.com

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9. Patient instructed for Tongue
movements and to purse lips.
8. Tray should be gently
seated.
11. Any short areas can be
remolded.
10. Impression should
cover all denture bearing
area. www.indiandentalacademy.com

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13. Inside surface reduced by
1-2 mm.
12. All bordrs reduced by 2-3
mm.
14. Thin mix of alginate
loaded.

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15. Completed preliminary impression made with
alginate using a compound tray.

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Preperation for Secondary
Impression
• Denture
outline
marked on
the primary
impression.
Completed
preliminary
casts.

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1. Denture outline accentuated. 2. Posterior border of tray
marked.distal to denture border.
3. Wax added for relief. 4. Special tray.
Secondary impression

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5.Borders should be beveled. 6. Vibrating line marked.
7. Tray inserted in mouth. 8. Overextensions
trimmed.www.indiandentalacademy.com

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12. Softened compound added
from hamular notch to buccal
space.
9. Tray should be short of
2 mm from base of sulcus 10. Borders should be adjusted.
11. Extra clearence in
frenal areas

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16. The tray rotated in mouth
and cheek gently massaged.
13. Compound molded with
fingers.
14. Softened again with alcohol
torch.
15. Tempered in warm water
bath. www.indiandentalacademy.com

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19. To record the frenum patient told to
purse the lips.
17. Appropriate molding will have mat
surface.
18. Compound added in buccal frenum
area.

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21. Recording the frenum.20. Molded buccal and labial
borders.
22. Excess compound on
tissue side trimmed.
23. Compound placed on
posterior border.

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25. Junction of tray and
compound smoothened.
24. Tray seated in mouth with
firm pressure.
26. Border molded
maxillary custom
tray.

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4. External oblique ridge
marked.
1. Tray outline marked 2-3 mm
short of denture outline.
2. Custom tray fabricated.
3. Posterior border of tray
should cover anterior half of the
pad. www.indiandentalacademy.com

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5. Pencil mark transferred
to fitting surface.
7. Anterior border of the tray adjusted .
6. Tray border should be
resting against the ridge.
8. Lingual border adjusted.

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9. Compound placed on posterior border
11. Compound added on
buccal border
10. The tray gently seated
in place.
12. The border should be
smooth,round and convex.

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13. Border molding continued in labial borders.
14. Border molding the lingual
areas. www.indiandentalacademy.com

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15. Genial tubercles
should be covered.
16. Border
molded
mandibular tray

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• Impression tray loaded with
Zinc oxide eugenol.•Clearance provided for frenum.
•Tray held gently in place. •Lips and cheek movements to be
done as material sets.www.indiandentalacademy.com

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• Completed
maxillary
final
impression.
Primary impression

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• Completed
mandibular final
impression.
Primary
impression.

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Closed mouth techniques.
• The denture has more accurate fit during
mastication.
• Impression material coated at bases of the blocks
and patient told to close in retruted contact
position.
• Patent given small amount of water to rinse.This
captures the normal movements of the surrounding
musculature.
• Material :
– thin zinc oxide eugenol,
– light body silicone.

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Closed mouth technique.
• Drawbacks of
– Maxillary Disto buccal space is not recorded in
function.
– Viscous impression material can lead to increase in
vertical dimension.
Advantages
• Discrepancies in the jaw relations,
resulting from points of premature contact
of the rims are eliminated.
• Masseter muscle can be recorded in
function.
.

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Mucodisplasive
• The impression material must be capable of
viscous flow as it is extruded under pressure
from between the tray and the tissue
surface.
• Materials used
– Impression compound
– High viscosity silicones
– Stiff zinc oxide eugenol.

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Mucostatic.
• Use a very fluid impression material, and
use minimal pressure while it sets.

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Selective pressure technique.
• It is a combination of extension for
maximum coverage within tissue tolerance
with light pressure or intimate contact with
the movable,loosely attached tissues in the
vestibules.
• The impression is refined with a minimum
of pressure.

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Clinical finding Primary
impressions
Secondary
impressions
T echnique
Good ridge form Impression
compund
Plaster of Paris,
zinc oxide/eugenol,
alginate or
elastomer
conventional
Sound denture supporting
tissues
No undercuts
As above but undercuts
present
Impression
compound
Alginate or
elastomer; depends
on degree of
undercuts
Impression technique
conventional but plan path of
insertion and removal of tray to
match that of the proposed
denture.
Good ridge form
Upper ridge displaceable
alginate Use a two-stage
impression
technique
Controlled mini~ally
displacive impression techniques
Ridge may look
satisfactory but consists of
fibrous tissue or has
non-corticated (e.g. knife-
edge) ridge-pain elicited
when palpated
Alginate or
medium-
bodied
elastomer
Zinc-oxide/eugenol
or light-bodied
elastomer
Controlled pressure impression
technique
Very atrophic ridges or
where optimum peripheral
extension is indeterminate
Impression
compound
Functional
impression method
Modify denture appropriately
and add impression material
which is mounded by
functional movements
Suggested impression techniques.

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