Relining and rebasing in complete dentures / Labial orthodontics courses

RELINING AND
REBASING IN
COMPLETE
DENTURES
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS
Introduction
General considerations
Indications
Contraindications
Tissue preparation
Denture preparation
Relining materials
Rigid materials
Short term-soft lining materials
Long term-soft lining materials

Relining procedures
Static methods:
open mouth technique
closed mouth technique
Functional methods
Chair side technique
Laboratory procedures
articulator method
jig method
flask method
conclusion
References www.indiandentalacademy.com

INTRODUCTION
The residual ridges have been described as plastic in
nature, always changing in topography and morphology from
many causes, some known and some unknown.
The clinical efforts that aim at prolonging the
useful life of complete denture involve a refitting of the
impression surface of a denture by means of a reline or a
rebase procedure.

Definitions
According to GPT 8 :
Relining :
The procedure used to resurface the tissue side of a
denture with new base material, thus producing an accurate
adaptation to the denture foundation area.
Rebase :
Rebasing is a process of replacing all the base material
of a denture. The purpose of which is to fill the space between
the tissue and denture base without changing the position of the
teeth and the relation of the dentures.

PATTERN OF RESORPTION
 vertical changes in basal seat area
 horizantal changes in basal seat area
 Changes in the maxilla
 Changes in the mandible

General considerations
A through examination of the patient and of the
existing denture must be accomplished before commencing
therapy.
1. vertical dimension
2. Centric occlusion should coincide with centric relation
3. The size, shape, shade, and arrangement of the artificial teeth
must be satisfactory.
4. The oral tissues should be in optimum health.
5. The posterior limit of the maxillary denture is correct.

6. The denture base extensions
7. Distribution of masticatory forces over as large an area as
possible.
8. The interocclusal distance is correct
9. Speech
10. redundant tissue or severe osseous undercuts.


INDICATIONS
 Immediate dentures at three to six months
 Adaptation of the denture base is compromised
 Cost
 physical or mental stress, such as for geriatric and
chronically ill patients.

Contraindications
1. Excessive resorption
2. Abused soft tissues are present.
3. Temporomandibular joint problems.
4. Poor esthetics
5. Unsatisfactory jaw relationships.
6. Speech problem
7. Severe osseous undercuts

Tissue preparation
 Hypertrophic tissues
 Free of areas of irritation.
 Removal of the dentures from the mouth during sleep is a must
for several weeks.
 The dentures should be left out of the mouth at least two to
three days before making final impression.
 Daily massage of the soft tissue

Denture preparation
 Pressure areas of the tissue surface of the denture
 Minor occlusal disharmony is corrected by selective grinding.
 Small border inadequacies are corrected.
 A correct posterior palatal seal area should be established
before the final impression.

RELINING MATERIALS

Hard and soft materials for modifying the
impression surface of dentures
• Rigid materials
• Short-term soft lining materials
• Long-term soft lining materials

Rigid materials
Frequently described as chair side reline
materials, which can be used to modify the impression
surface of an existing denture.
Composition :
Powder – polyethylmethacrylate
Liquid monomer – butylmethacyrlate
Many of the products include a primer to enhance
the adhesion of the material to the existing denture
polymer. The available materials vary in working time,
setting time and viscosity.

Manipulation:
Relieve the fitting surface of the denture.
Mix powder and liquid in 1:2.5 to attain a fluid mix.
Applied to the fitting surface of the denture and seated in
patients mouth while it is still fluid.
The reline soon becomes rubbery and the impression of the
patients soft tissue is recorded.
The denture is allowed to bench cure after removal from the
patients mouth. Warm water will accelerate the curing.
The relined denture is ready within 30 minutes.

Short term soft relining materials
Composition :
Powder : Polyehtylmethacrylate
Liquid : mixture of
An aromatic ester, such as dibutyl pthalate which acts as a
plasticizer.
Ethyl alcohol
The setting process :
After the powder and liquid have been mixed, the ethyl
alcohol causes swelling of the polymer particles and permits
penetration by the ester so that a gel is formed. This is a
physical change ; there is no chemical reaction.

Clinical applications :
Short-term soft lining materials are placed in the existing
dentures for the following reasons.
 Tissue conditioning
 Temporary soft reline – improve fit of denture
 Functional impression

Long-term soft lining materials
 Thin atrophic mucosa
 Replacing an existing denture which has a soft lining
 Sharp bony ridges or spicules
 Superficially placed mental nerve

Types of long-term soft lining
Soft liners are made either of
Silicon rubber - Cold curing
Heat curing
Soft acrylic - Cold curing
Heat curing


Relining procedure

Relining procedure
Clinical procedure Laboratory procedure
1. Static methods
2. Functional method
3. Chair-side technique
1. Articulator method
2. Jig method
3. Flask method
closed–mouth
technique
Open- mouth
Technique(Bouchers)

Open mouth technique ( boucher )
 Relining of both dentures at same time
 New centric relation is recorded
 Selective pressure technique
 Interocclusal record with quick setting plaster

FUNCTIONAL METHOD (WINKLER)
 Easy to use
 Excellent for refitting of denture
 Good dimensional stability
 Good in bonding to denture base resins

Tissue conditioners

This material undergoes through
Plastic stage - few hrs – few days.
Elastic stage - 1 – 2 weeks.
Firm stage - after 15 days.

CHAIRSIDE RELINE PROCEDURE
DISADVANTAGES:
 chemical burn
 material is porous and
develops a bad odour
 poor color stability
 material not easy to remove
if not placed correctly

VISIBLE LIGHT CURE ( VLC )
 Similar to tisssue conditioners
 Select appropriate viscosity and partial intraoral
polymerisation with hand-held curing light
 Taken to laboratory for unpolymerised molecules

LAB PROCEDURES

Beading Boxed impression
Stone pouring
Indexing
separating media applied
Articulator method

Modeling clay application Stone over lower member
Positioning denture in stone Stone placed on cast basewww.indiandentalacademy.com

Modeling clay removed Removing all impression material
Impression surface reduction Border reduction – 2-3 mm

Resin grindings removed with
Stream of air
Providing posterior seal
Separating medium application
resin application over the denturewww.indiandentalacademy.com

Resin placed on the cast Denture seated in indentations
Cured in pressure container
- 20 psi for 30 minutes
Relined denturewww.indiandentalacademy.com

Jig method
Hooper duplicator Jectron jig

Procedure
Denture seated on lower
Member of jig
Mounting stone smoothened with
spatula
Locknuts ,modeling clay
removed
Jig openedwww.indiandentalacademy.com

Denture carefully lifted Blowing air to lift
Preparing basal surface prepared Cleaned prepared denture seated
In stone index

Application of separating media Moistening with monomer
Resin mixed & placed on cast Resin placed in denturewww.indiandentalacademy.com

Jig assembled & locknuts
tightened
Jig separated & denture
Examined for voids
Polished Relined denture

Rebasing with jig method
Hooper Duplicator used to rebase the denture
Denture seated in the index in Hooper Duplicator

Removal of porcelain teeth
Using alcohol torch Using Spatula
Porcelain teeth replaced back A layer of baseplate wax
adapted to the castwww.indiandentalacademy.com

If insufficient space is there
Baseplate wax is removed
wax can be added
Completed wax-up on jigwww.indiandentalacademy.com

Waxed denture removed & flasked. Rebased denture is replaced on jig

Flask method
Denture half - flasked Painting silicone mold material

Flask opened
Porcelain teeth removed &
Replaced in silicone mold
Resin teeth replaced, Cure denturewww.indiandentalacademy.com

Rebasing with Articulator method
Mandibular denture with porosities

Border trimmed-2mm Border molding with green
stick compound

Final impression with Zinc-oxide
Eugenol
Master cast fabricated

Indentations of the teeth made Cast mounted on upper member

Denture trimmed Wax build-up donewww.indiandentalacademy.com

Invested waxed denture

CONCLUSION
clinical evidence suggest that the rate of osseous change
can be retarted when complete dentures are readapted to the
residual ridges at the first signs and symptoms of loss of
adaptation. The clinical efforts that aim at prolonging the
useful life of complete denture involve a refitting of the
impression surface of a denture by means of a reline or a
rebase procedure.

Thank you
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Relining and rebasing in complete dentures / Labial orthodontics courses

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