Relining,repairing and rebasing of denture in prosthodontics..

1. Manali Rajvansh
student at Awadh Dental college,
Jamshedpur

2. First Steps In Making A Denture
•Primary impression
•Diagnostic cast
•Custom tray
•Final impression
•Master cast

3. Primary
impressions
Conventional techniques
Template techniques
Definitive
impressions
I- Conventional techniques
II- Selective pressure techniques
III- Functional techniques
IV- Reline and rebase techniques
(including secondary template impressions).

5. Repair of Complete
Dentures

6. Dentures may fracture
during function
dropped on hard
surface
Key of repair = accurate reassembling
& alignment of the broken parts in
their original position.

7. Classification of fractured
dentures
I) According to location of fracture
Midline fracture
Any part fracture

8. II) According to extent of fracture
Without broken or
missing part &/or
teeth
With broken or
missing part &/or
teeth

9. III) According to timing of fracture
Early fracture
Delayed fracture
IV) According to cause of fracture
Operator
Patient

10. Midline fracture
(mainly in maxillary dentures)
Causes:
1) No or insufficient relief in the midline. (M.P.R.)
(Early fracture)
2) Ridge resorption
(Delayed fracture)
with
loss
of
relief
effect.

11. Procedures for repair of midline
fracture:
• Broken parts are
assembled
&
fixed
together with sticky
wax on the polished
surface.
• Assembled parts may
be strengthened with
burs or plastic sticks.

12. Procedures for repair of midline
fracture:
• Any undercut on the
fitting surface is blocked
out with wax or clay.
• The fitting surface is
painted
medium.
with
separating

13. • Stone plaster is poured
into the fitting surface.
After stone setting, the
denture is removed from
the cast and cleaned
from any traces of sticky
wax.
• Fractured edges are
reduced, widened (8-10
mm) along the fracture
line and beveled towards
the polished surface to
increase
bonding
surface area.
• Dove tail cuts may be
made to strengthen the
repair joint.

14. • The cast is painted with separating
medium and the denture is secured to
the cast with rubber bands.
• Self cure A.R. is applied to the
modified fracture area until the area is
overfilled.
N.B. An alternate method is to wax
and contour the fracture line to the
desired form using base plate wax,
followed by flasking, wax elimination,
packing with self cure A.R. and
placing in the flask under press for 2
hrs.
• Deflasking, finishing and polishing is
then done in the usual manner.

15. • Reline if needed.
• Remake in some cases.

16. Any part fracture
Main cause is falling on the ground or the sink
during cleaning.
Types:
I- Fracture with no missing part
Repaired as mentioned.

17. II- Fracture with missing or lost part
Procedures:
• An impression is made
with the denture placed
in patient mouth.
• After pouring the cast,
either self cure A.R. is
applied to replace the
missing part, or wax is
added and carved to
resemble
the
broken
denture part, followed by
flasking, packing, curing,
finishing & polishing .

18. III- Fracture with broken or missing
teeth
Procedures:
• Fractured teeth are
cut away with burs.
• On the lingual side,
enough
acrylic
is
removed
and
dove
tailed.
• Teeth of same size,
shape & shade are
positioned in proper
alignment and waxed
with base plate wax.

19. • A plaster index (key) is made
to record & secure the position
of waxed teeth.
• Teeth to be repaired are
removed together with all wax
around them.
• Teeth are then put back
exactly in their original position
aided by plaster key.
• Self cure acrylic resin is
added from the lingual side
until repair area is over built. It
is then covered with tin foil.
• After curing, the index is
removed and the denture is
finished and polished.

20. Relining of Complete Dentures
Def:
Resurfacing or correction of denture
adaptation to underlying tissues by the addition
of a new resin material to its fitting surface
without changing its occlusal relation.
Addition of Material to the tissue side of a
denture to improve its adaptation to the
.supporting mucosa

21. Whenever the denture loses or has poor adaptation to the
underlying tissues, while all other factors as occlusion,
esthetics, centric relation, V.D.O. and denture base
material are satisfactory.

Loss of retention

Instability

Food under denture

Abused mucosa

22. 
Optimal tissue health

Reasonable CR/CO

Adequate vertical dimension

Adequate peripheral extensions

23. Procedures:
• Patient is instructed to leave his denture out of
his mouth at least 48 hrs to allow for recovery of
tissues and reduce irritation caused by ill-fitted
denture.
Denture preparation:
•
Any
undercuts
are
removed from the denture
base.
• Peripheral extensions are
checked and adjusted.
• Borders are reduced and
squared
to
provide
a
definite edge for addition of
new resin material.

24. • A hole is made in the
palatal
surface
to
allow
escape of excess impression
material. Slight reduction in
the fitting surface may be
done to create some space
for the impression material.
• Border tracing & new
impressions are made under
centric occlusion to maintain
occlusal relationship.
•
The
denture
with
impression material is boxed
and poured into stone.

25. . The denture is flasked, and the old resin material
is thoroughly cleaned and roughened.

26. . New acrylic resin material is packed, and the
denture is cured in pressure curing unit containing
water at 45°c for 20 min. to prevent porosity of
new resin material and warpage of the old resin
material (release of internal stresses).
. Finishing and polishing is done in the usual
manner.

27. N.B.
When both upper and lower dentures need
relining, lower denture should be completed first .
The upper may be relined against a stable lower
denture.
The denture should be clinically remounted to
perfect the occlusion.

29. If after modifications, the “fit and bite” seem
improved, let the patient try the denture for
one week…if there is no improvement, then
reline.

30. Overextension
Irritation of Peripheral Borders

31. Overextended borders
Borders corrected

32. Error in CO on one
side, will break the
seal on the opposite
side

33. Correct eccentric excursions

34. 1.
2.
3.
Loss of stability and retention
Irritation and inflammation on one side
Teeth stained on one side

35. 1.
2.
3.
4.
5.
Worn out dentures
Vertical dimension loss greater than 7 mm
Significant mucosal inflammation
Poor denture esthetics
Denture related speech problems

36. •Severe tooth wear
•Severe vertical overlap
with tooth wear (posterior
tooth concept)
•Severe occlusal wear (CD
evaluation)

37. Recognition of abused tissues, with
superimposed candidiasis.

38. 




Intermittent hot and cold rinses
Massage tissues
Relieve pressure areas
Correct faulty occlusions and denture
borders
Minimize stress by
 Soft
diet
 Removal of denture at night

Use tissue conditioners

39. 
Healthy Tissues!!

40. 1. Check extensions
3. Border Reduction
2. Indicate amount of
peripheral reduction required
4. Tissue Conditioner preparation:
Peripheral reduction + Tissue

41. 5. Border Molding
Completed
7. Seat denture until wash
comes through vents
6. Palatal surface vented
after B. M.
8. Final Impression

42. 
Incorrect seating.
Improper plane of
orientation:
 Not
contacting teeth
 Excess material
 No vents


Place ZnO wash
Have patient close
in CR.

43. Trim
excess wax
beyond
anterior
line
ZnO wash. Posterior
palatal seal area
using impression
wax
Reline final
impression

44. Final Impression with PVS
Final Impression with Rubber base

45. 
Identify in
impression, before
pouring it up.

Identify on
impression so
technician can scribe
the seal

46. Complete
Denture methodZnO
Border
molding
completed
Rubber Base
Reline

47. Roughened
border to blend
new acrylic with
old. Won’t show
finishing line
Relined cast: Do
not separate
After
processing:
Note junction
line

48. Trimmed and polished

49. Examine:
•Peripheral extensions

50. 

Pressure Indicator
Paste (PIP)
Ask the patient to
bite on cotton rolls
for 5 min.

62. Rebasing of Complete Dentures
Def: It is a process of readaptation of a denture
to the underlying tissues by replacing the denture
base material with a new one without changing its
occlusal relation.
Indications:
When the existing denture base is unsatisfactory
e.g. stained, crazed or porous.

63. Procedures:
• An impression is made with
the denture and a cast is
obtained.
• An occlusal and incisal
index of the teeth is made in
plaster
using
Hooper
duplicator The posts of the
lower part of the duplicator
are seated in the upper part
to maintain the relationship
of the casts to the plaster
index.

64. • The denture with the impression material are
removed from the cast.
• Artificial plastic teeth are sectioned from the
denture and all base material around the teeth is
removed. (porcelain teeth are removed by
flaming)
• Teeth are placed and held in position in the
index using sticky wax on the labial and buccal
surface.
• A layer of base plate wax is placed over the
ridge of the cast.

65. • The upper part of the duplicator is closed and
denture teeth are waxed to the proper thickness
and contour to the cast.
• The cast is removed, flasked and processed in
the usual manner.
• After deflasking, the cast is reattached to the
upper part of the duplicator to adjust any
occlusal errors.
• Occlusion of rebased denture
perfected by clinical remount.
is
further