prosthetic treatment of FLAT ridge-PPT.ppt

problems of flat ridge; The shape of the osseous structures in these patients offers little possibility of retention and stability of complete dentures.
Muscle attachments are located near the crest of the residual ridge and, consequently, the dislocating effect of the muscles on the denture is great.

1. Prosthetic management
of flat ridge (impression
techniques)
Radhwan Saleh
Current Prosthodontics

2. ManagementManagement::
I- Prosthetic management without
surgical intervention
II- Prosthetic management with
surgical intervention

3. I- Prosthetic management without I- Prosthetic management without
surgical interventionsurgical intervention
The shape of the osseous structures in these The shape of the osseous structures in these
patients offers patients offers little possibility of little possibility of
retention and stabilityretention and stability of complete of complete
dentures. dentures.
Muscle attachments are located near the Muscle attachments are located near the
crest of the residual ridge and, crest of the residual ridge and,
consequently, the consequently, the dislocating effect dislocating effect of the of the
muscles on the denture is great.muscles on the denture is great.
Problems of flat ridgeProblems of flat ridge

4. So;So;
Success of complete dentures largely Success of complete dentures largely
depends on depends on accuracy of impressionaccuracy of impression. .
Accurate impression needs a thorough Accurate impression needs a thorough
understanding of understanding of anatomy, physiology of anatomy, physiology of
supporting structures, properties and supporting structures, properties and
manipulation of materials.manipulation of materials.

5. An ideal impression should provideAn ideal impression should provide::

Maximum extension without muscle Maximum extension without muscle
impingement.impingement.

Intimate contact with the tissue area Intimate contact with the tissue area
covered.covered.

Proper form of the borders including Proper form of the borders including
the posterior border of the maxillary the posterior border of the maxillary
denture.denture.

Proper relief of hard and sensitive Proper relief of hard and sensitive
areas.areas.

6. Different impression techniques could be Different impression techniques could be
made according to the condition of the made according to the condition of the
supporting tissue:supporting tissue:
1. Conventional impression technique.
2. Muco-compressive impression technique.
3. Butterfly impression technique.
4. Dynamic impression technique.
5. Neutral zone impression technique.

7. 1. Conventional impression technique1. Conventional impression technique
Utilizing Modified Special Tray
a. Alginate impression material
- Stub handles:
. Act as finger rests
. Reducing the possibility of
distorting the sulcular form of impression
- Spacing 3mm
- Border molding

8. b. Zinc oxide and Eugenol imp. Paste or
Rubber base
- No spacing (close fitting tray)
- Border molding
- Stub handles:
. Act as finger rests
. Reducing the possibility of distorting the
sulcular form of impression

9. Rubber base impression
Technique

10. •Underextension may be corrected by adding
tracing compound or a similar material
•the compound should be added to displace the
retro-molar pad sufficient to give a posterior seal

11. lifts the finger
away from the
tray borders
preventing it from
becoming part of
the denture
impression .
Prevent breakage by adding a spine of
acrylic along the crest of the ridge

12. your finger is too your finger is too
close to the tray close to the tray
border, then the border, then the
impression material impression material
will follow around will follow around
your finger, making your finger, making
a circular and a circular and
obviously incorrect obviously incorrect
impression. impression.
Note: imprint where fingers were
placed to seat the tray.

13. Note: areas of distortion on distobuccal
borders .
Rubber base impression Technique

14. Idea :
Mucofunctional or
compression
impressions is a closed
mouth impression
technique recording the
tissues under function.
2. Muco-compressive impression technique.

15. Primary impression:
Impression compound
Special trays: Occlusion blocks at accepted VD.

16. Border molding: Using green stick compound
or rubber base until a stable and retentive tray is
obtained.

17. Final impression: Is made using zinc oxide
and eugenol while the patient is closing on
the occluding rims (closed mouth technique)

18. 3. Butterfly impression technique.
This technique is indicated in case of
advanced resorbed ridge with projecting
sublingual glands.

19. A primary impression:A primary impression:
•Stock tray; lingual border is made nearly
flat to cover the sublingual crescent area.
•Alginate impression material.

20. An acrylic resin special tray An acrylic resin special tray is fabricated
with a butterfly extension over the sublingual
crescent area
Occlusion rim Occlusion rim is added to simulate the height
and position of the anterior and posterior teeth.

21. The borders The borders are adjusted.
Three applications Three applications of tissue conditioning
material are used with closed mouth
technique.
Two application of a viscous tissue conditioning Two application of a viscous tissue conditioning
material. material. Each application is allowed to remain in
the mouth for 8-10 minutes pressure areas are
corrected after each application.
Third wash is made Third wash is made using either a soft tissue
conditioning material or a light-bodied rubber base
impression material.

22. Idea: This technique is used to record the
range of muscle actionrange of muscle action as well as spaces into
which the denture can be extended without
displacement
The advantages of dynamic impressions are :
(1)avoidance of the dislocating effect of the muscles
on improperly formed denture borders
(2) Complete utilization of the possibilities of active
and passive tissue fixation of the denture.
44 - -Dynamic impression techniqueDynamic impression technique

23. Primary impression: is made with
impression compound.
Jaw relationship: tentative record and
set up a trial maxillary denture

24. Stoppers on the fitting surface (allow a correct
orientation of the tray on the residual ridge)
 Special tray:
•Three stops of impression compound are Three stops of impression compound are
added to the fitting surface of the trayadded to the fitting surface of the tray

25. The stops must contact
the upper teeth at the
selected OVD.
•The upper denture is set up The upper denture is set up
conventionally to the conventionally to the
prescribed occlusal vertical prescribed occlusal vertical
dimension (OVD). dimension (OVD).
•Opposing the upper
set-up is a resin base
with three vertical stops
joined by a wire

26. 
Final impression is made using a Final impression is made using a thin mix thin mix
of alginate impression material.of alginate impression material.


Then, the patient is asked to close slowly Then, the patient is asked to close slowly
until until the mandibular rests firmly contact the mandibular rests firmly contact
the maxillary denture and keep his tongue the maxillary denture and keep his tongue
is in contact with the tongue rest is in contact with the tongue rest

27. 
The patient is instructed to swallow The patient is instructed to swallow
3-4 times, forcefully protrude the 3-4 times, forcefully protrude the
lips forwards and contract the lips forwards and contract the
buccinator muscles in between buccinator muscles in between
swallowsswallows

28. The resulting impression covers the
maximum possible basal seat area and
the borders are in harmony with the
adjacent moving tissues.
Dynamic dentures differ
characteristically from conventional
dentures: The borders of the denture
base from a dynamic impression are
longer lingually and buccally in relation
to the amount of extension obtained
from a conventional impression.

29. Neutral zone: the potential space
between the lips and cheeks on one side
and the tongue on the other; that area or
position where the forces between the
tongue and cheeks or lips are equal(GPT
7)

5. Neutral zone impression technique.

30. Indications of denture space/neutral zone
•It is designed for patients with poor track It is designed for patients with poor track
records of (lower) denture stability records of (lower) denture stability
•The concept is based on the belief that the The concept is based on the belief that the
muscles should functionally mold not only muscles should functionally mold not only
the border and the artificial teeth but also the the border and the artificial teeth but also the
entire polished surface. Facial and lingual entire polished surface. Facial and lingual
forces generated by the muscles of the lips, forces generated by the muscles of the lips,
cheeks and tongue are balanced. cheeks and tongue are balanced.

31. (A and B) The lower ridge is tapered and
severely atrophic
Preoperative panoramic radiograph

32. Primary impression
The lower tray is checked by having the patient say ah,
ee, and oh, using an exaggerated motion of the lips and
cheeks to pronounce these sounds.
Modifying the acrylic resin tray

33. Establishing the neutral zone
A soft material that can be molded by the action
of the tongue, cheek, and lips is used to establish
the neutral zone. (modeling compound).
The modeling compound is trimmed so that the
occlusal plane is established Approximately 1 to
2 mm. below the lateral border of the tongue
when it is at rest.

34. Centric and vertical relations
Final impressions
Soft modeling compound is then attached to the
upper tray and molded to the approximate shape of
an upper occlusion rim.

35. Constructing tongue, lip and cheek indices

36. (A-B) Before the tray was removed, a silicone matrix was made
to represent the neutral zone space

37. The teeth were arranged within
the neutral zone.
Arranging Artificial Teeth and
Establishing the Polished Surface

38. (A-F) Final complete dentures. (E and F) Fit
checker was used to check the neutral zone space.
The result was of little difference.

39. Jaw relation registration
Is carried out using check bite technique.
Occlusal plane is adjusted nearer to the
flat ridge to decrease the lever arm.

40. The design of the finished denture The design of the finished denture
should have the following characters:should have the following characters:
Broad coverage area for maximum force
distribution and maximum retention.
Dentures constructed for severely
resorbed ridge should be accompanied
with thicker denture borders than the
average.
Reduction of the occlusal table width of
teeth for maximum force distribution.

41. Avoidance of inclined planes of artificial
teeth (use of cross-linked cuspless
nonanatomic teeth) to minimize the
dislodging forces and decrease the amount
of forces necessary for food bolus
penetration.
Provision of adequate tongue space to
improve stability of the denture during
speech and mastication.

42. Adequate inter-occlusal distance during rest
relation of the jaw to decrease the
frequency and duration of teeth contact
(slight increase in interocclusal distance is
required, but over closure is not).
A metal denture base is preferred to
increase retention by interfacial surface
tension.