Transcript Complete Dentures

Repair, relining and rebasing
Dr. Amal Fathy Kaddah
Professor of Prosthodontic,
Faculty of Oral &Dental Medicine,
Cairo University
www.egydental.com
First Steps In Making A Denture
•Primary impression
•Diagnostic cast
•Custom tray
•Final impression
•Master cast
Impression Techniques
 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).
Complete Dentures
Repair of Complete Dentures
Dentures may fracture
during function
dropped on hard
surface
Key of repair = accurate reassembling
& alignment of the broken parts in their
original position.
Classification of fractured dentures
I) According to location of fracture
Midline fracture
Any part fracture
II) According to extent of fracture
Without broken or
missing part &/or
teeth
With broken or
missing part &/or
teeth
III) According to timing of fracture
Early fracture
Delayed fracture
IV) According to cause of fracture
Operator
Patient
Midline fracture
(mainly in maxillary dentures)
Causes:
1) No or insufficient relief in the midline. (M.P.R.)
(Early fracture)
2) Ridge resorption with loss of relief effect. (Delayed
fracture)
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.
Procedures for repair of midline fracture:
• Any
undercut
on
the
fitting surface is blocked
out with wax or clay.
• The
fitting
surface
is
painted with separating
medium.
• 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.
• 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.
• Relief of the median palatine
raphea.
• Reline if needed.
• Remake in some cases.
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.
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.
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.
• 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.
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.
Reline Indications
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
Reline: General Considerations

Optimal tissue health

Reasonable CR/CO

Adequate vertical dimension

Adequate peripheral extensions
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.
• 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.
. The denture is flasked, and the old resin material is
thoroughly cleaned and roughened.
. 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.
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.
Evaluate Dentures
Is Reline necessary????
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.
Is reline Necessary?
Overextension
Irritation of Peripheral Borders
Is reline Necessary?
Overextended borders
Borders corrected
Is reline necessary?
Error in CO on one
side, will break the
seal on the opposite
side
Is reline necessary?
Correct eccentric excursions
Diagnosis-Occlusal
disharmony
1.
2.
3.
Loss of stability and retention
Irritation and inflammation on one
side
Teeth stained on one side
Reline Contraindications
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
Contraindications
•Severe tooth wear
•Severe vertical overlap
with tooth wear (posterior
tooth concept)
•Severe occlusal wear (CD
evaluation)
Pre-requisites for relining
Recognition of abused tissues, with
superimposed candidiasis.
Initiate Tissue Recovery
Program





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
Complete Denture Exam
Healthy Tissues!!

CUD Reline
1. Check extensions
3. Border Reduction
2. Indicate amount of
peripheral reduction required
4. Tissue Conditioner preparation:
Peripheral reduction + Tissue surface
CUD Reline
5. Border Molding
Completed
7. Seat denture until wash
comes through vents
6. Palatal surface vented
after B. M.
8. Final Impression
CUD Reline
Incorrect seating.
Improper plane of
orientation:

Not contacting teeth –
Excess material –
No vents –
Place ZnO wash
Have patient close
in CR.


CUD Reline
Trim
excess wax
beyond
anterior
line
ZnO wash. Posterior
palatal seal area
using impression
wax
Reline final
impression
Final Impression with PVS
Final Impression with Rubber base
post palatal seal
combination
Identify in
impression, before
pouring it up.
Identify on
impression so
technician can
scribe the seal


CLD Reline
Complete
Denture methodZnO
Border
molding
completed
Rubber Base
Reline
Reline
Roughened
border to blend
new acrylic with
old. Won’t show
finishing line
Relined cast: Do
not separate
After
processing:
Note junction
line
Reline
Trimmed and polished
Delivery of Reline
Examine:
•Peripheral extensions
Delivery of Reline
Pressure Indicator
Paste (PIP)
Ask the patient to
bite on cotton rolls
for 5 min.


LABORATORY REMOUNTING
CLINICAL REMOUNTING
Perfection of occlusion
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.
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.
• 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.
• 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
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