Impression procedures /certified fixed orthodontic courses by Indian dental academy

IMPRESSIONS PROCEDURES

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


1

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.

2

Operator position for maxillary
impression

• Correct

Incorrect

3

Operator position for Mandibular
Impression

Correct

Incorrect

4

Techniques.
•Single stage

• Open mouth
– Mucocompres
sive
– Mucostatic
– Selective
pressure

•Double stage

• Closed mouth.

5

Conventional two stage
procedure.


6

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.

7

Primary Impression in alginate.

1.Selection of stock tray.

2. Position borders at hamular notches.

3. Lift the tray anteriorly, 3-5 4. Tray should be adjusted by
mm space for impression
bending .
material.

8

5. Border of ray should be
short of tissue reflection.

6. Adequate clearance in
frenal areas.

7. Tray should be
smoothened.


9

8. Deficient borders corrected by
adding utility wax.

9. Tray extension in buccal space
and tissue side of posterior
border.

10. Tissue stop in central
portion of tray.

10

11. Location of hamular notches.

12. Mark the vibrating line.

13. Some alginate to be
14. Alginate to be placed
placed in vestibule. www.indiandentalacademy.com
in deepest part of palate. 11

15. Tray to be rotated into the
mouth and seated first at the
back of the mouth.

16. Upper lip elevated.

18. Labial and buccal borders
to be
www.indiandentalacademy.com molded.
12

17. Tray is held in the mouth.

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


13

Mandibular alginate impression.

1.Britania metal edentulous tray.

2. Retromolar pad should be
identified
3 . Tray should cover retromolar
pad and rest against external
oblique ridge.


14

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

15

6. Patient told to raise the
tongue and tray is rotated in
the mouth.

7. Patient told to do tongue
movements.

8. Gently mold the labial and buccal areas.

16

• Completed Mandibular Primary Impression.


17

Alternative Techique for primary impression

Alginate impression in
compund tray.

1. Modelling compund.

2. Softenend in water
bath and kneaded.
3. Compound placed in
the tray.


18

4. Molded with fingers to
ridge form.

5. Should cover mylohyoid ridge
and external oblique ridge.

6. Gently warmed over a flame.

7. Before insertion, tempering
in warm
www.indiandentalacademy.com water bath.
19

8. Tray should be gently
seated.

9. Patient instructed for Tongue
movements and to purse lips.

10. Impression should
11. Any short areas can be
cover all denture bearing
remolded.
area.

20

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

21

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


22

Preperation for Secondary
Impression

• Denture
outline
marked on
the primary
impression.
Completed
preliminary
casts.


23

Secondary impression

1. Denture outline accentuated.

2. Posterior border of tray
marked.distal to denture border.

3. Wax added for relief.

4. Special tray.

24

5.Borders should be beveled.

6. Vibrating line marked.

7. Tray inserted in mouth.

8. Overextensions
trimmed.

25

9. Tray should be short of
2 mm from base of sulcus

11. Extra clearence in
frenal areas

10. Borders should be adjusted.

12. Softened compound added
from hamular notch to buccal
space.
26

13. Compound molded with
fingers.

14. Softened again with alcohol
torch.

16. The tray rotated in mouth
15. Tempered in warm water
and cheek gently massaged.
bath.
27

17. Appropriate molding will have mat
surface.

18. Compound added in buccal frenum
area.

19. To record the frenum patient told to
purse the lips.

28

20. Molded buccal and labial
borders.

22. Excess compound on
tissue side trimmed.

21. Recording the frenum.

23. Compound placed on
posterior border.


29

24. Tray seated in mouth with
firm pressure.

25. Junction of tray and
compound smoothened.

26. Border molded
maxillary custom
tray.


30

1. Tray outline marked 2-3 mm
short of denture outline.

2. Custom tray fabricated.

3. Posterior border of tray
4. External oblique ridge
should cover anterior half of the
marked.
pad.
31

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.


32

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.


33

13. Border molding continued in labial borders.

14. Border molding the lingual
areas.

34

15. Genial tubercles
should be covered.

16. Border
molded
mandibular tray

35

•Clearance provided for frenum.

•Tray held gently in place.

• Impression tray loaded with
Zinc oxide eugenol.

•Lips and cheek movements to be
done as material sets.
36

• Completed
maxillary
final
impression.

Primary impression


37

• Completed
mandibular final
impression.

Primary
impression.

38

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.


39

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,
. from points of premature contact
resulting
of the rims are eliminated.
• Masseter muscle can be recorded in
function.
40

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.

41

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


42

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.


43

Suggested impression techniques.
Clinical finding

Primary
impressions

Secondary
impressions

T echnique

Good ridge form

Impression
compund

Plaster of Paris,
zinc oxide/eugenol,
alginate or
elastomer

conventional

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. knifeedge) ridge-pain elicited
when palpated

Alginate or
mediumbodied
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
Modify denture appropriately
impression method and add impression material

Sound denture supporting
tissues
No undercuts


which is mounded by
functional movements

44

Leader in continuing dental education


45

Impression procedures /certified fixed orthodontic courses by Indian dental academy

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Andere mochten auch

Andere mochten auch (20)

Mehr von Indian dental academy

Mehr von Indian dental academy (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Impression procedures /certified fixed orthodontic courses by Indian dental academy