Dipal reline n rebase

RELINING AND REBASING IN
COMPLETE DENTURES
Dr. Dipal Mawani
Post Graduate student

CONTENTS
• INTRODUCTION
• DEFINITION
• TREATMENT RATIONALE
• INDICATIONS and CONTRAINDICATIONS
• PRETREATMENT PROCEDURES
• REQUIREMENTS OF SUCCESSFUL MATERIALS
• TYPES OF RESILIENT LINERS
• CLINICAL IMPRESSION PROCEDURES
• LABORATORY PROCEDURES
• CAUSES OF FRACTURE IN DENTURES
• METHODS FOR REPAIR
• SUMMARY
• REFERENCES

INTRODUCTION
•Both biological supporting tissues and materials used in complete
denture fabrication are vulnerable to time- dependent changes.
•When denture needs to be refitted, it usually indicates undermined
retention, sore spots, and variable denture bearing tissue hyperemia.
•The relining and rebasing of complete dentures involves solving all
of the problems encountered in the construction of new dentures,
except positioning individual teeth.

DEFINITIONS
RELINING –
- It is the process of adding some material to the tissue side of a
denture to fill the space between the tissue and the denture base.
(Winkler)
Or
the procedures used to resurface the intaglio of a removable
dental prosthesis with new base material, thus producing an accurate
adaptation to the denture foundation area (GPT-9)
REBASING –
- It is a process of replacing all the base material of a denture.
(Winkler)
Or
- The laboratory process of replacing the entire denture base
material on an existing prosthesis. (GPT-9)

TREATMENT RATIONALE
► The foundation that supports a denture changes adversely as a result of
varying degrees and rates of residual ridge resorption.
► These changes may be insidious or rapid, but they are progressive and
inevitable and are accompanied by:-
Loss of retention and stability.
Loss of vertical dimension of occlusion.
Loss of support for facial tissues.
Horizontal shift of dentures:- Incorrect occlusal relationships.
Reorientation of occlusal plane.
Reline Rebase
Minimal to moderate Moderate to maximal
changes changes

► The reasons for relining are:-
1) To Improve Retention & Stability:-
- Loss of fit will make the maintenance of peripheral seal impossible and will
greatly impair the retentive effects of adhesion & cohesion.
2) To Restore the Vertical Dimension:-
- If the vertical dimension to which a denture was made is reduced,
masticatory efficiency is impaired, but the previous efficiency can usually
be restored by relining.
3) To Improve the Appearance:-

4) To Restore the Evenness of Occlusal Pressure:-
- When there is any alteration in the fit of the dentures, there will be
some alteration of the pressure transmitted to the tissues when the
teeth are brought into occlusion.
5) To Relieve Pain:-
- If a denture has been worn with comfort and then becomes painful, it
is usually due to the alteration in the supporting tissues allowing the
dentures to tilt, rock or move, and transmit undue pressure on one
area.

INDICATIONS
► Immediate dentures at 3-6 months after their original construction.
► When the residual alveolar ridges have resorbed and the adaptation
of the denture bases to the ridges is poor.
► Persistent denture sore mouth.
► Congenital or acquired oral defect: (Acquired defect due to surgery
for malignancy, trauma, congenital defects like cleft palate)
► The need for promotion of mucosal healing.
► Irregular foundation: Sharp knife edge residual ridge, maxillary or
mandibular tori, prominent mylohyoid ridge.
► Single denture opposing natural teeth.
► Radiation therapy for tumors of face and neck.

PRETREATMENT PROCEDURES
► TISSUE PREPARATION:-

► PRINCIPAL PITFALLS:-
1) Do not increase the occlusal vertical dimension.
2) Multiple even contacts should be present in centric relation.
3) Do not permit the maxillary denture to move forward during
impression making.
4) Ensure that CR and CO are identical.
5) Ensure that an accurate PPS has been established.
6) An equal thickness of final impression material should be used.

Ideal requirements of successful
materials
►Ease of processing
► Dimensional stability during and after processing
► Low water absorption
► Adequate bond strength to rigid denture base resin
► High abrasion resistance: To resist rupture during use.
►Permanent resiliency: It should retain its resilience for longer period
► Color stability
►Minimum solubility in saliva: Plasticizer should not leach out
► No adverse effect on denture base: Like distortion, reduction of strength, crazing or
blanching.
►Ease in cleansing
► Biocompatibility

Types of Resilient liners
►Natural rubbers.
►Vinyl co-polymers.
►Hydrophilic polymers.
►Silicone based compounds.
►Acrylic based compounds.
►Treatment liners (soft conditioners)
Room temperature polymerized condensation
silicone rubber.
γ-methacrylate propyl trimethoxy silane
heat polymerized silicone rubbers
(molloplast B )

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)

STATIC IMPRESSION
TECHNIQUE
Static impression technique involves the use of either a closed
or open mouth reline/rebase procedure.
In closed mouth technique the dentures are used as an
impression trays and either the existing centric relation
occlusion (CRO) is used or the centric relation (CR) is
recorded before the impressions are made.

TECHNIQUE A
Centric relation: - a new centric relation record is made using wax
or modelling compound
Denture preparation: -
•large undercuts are relieved
•borders are reduced 1-2 mm except the posterior border of maxillary
denture
Shaffer FW, Filler WH: Relining complete denture with minimum occlusal error. J
Prosthet Dent 1971;25:366-370
Closed Mouth Relining Techniques:- Maxillary Denture

Special suggestion:-
Shaffer FW, Filler WH: Relining complete denture with minimum occlusal error. J Prosthet
Dent 1971;25:366-370
A part of the palate of the maxillary denture is removed to aid in
the proper positioning of the denture when the final impression
for the reline is made.

Border molding:- The borders of the dentures are reformed to their
functional contours by using low-fusing modelling compound.
Impression:- Zinc oxide-eugenol impression paste is suggested as
the impression material.
Shaffer FW, Filler WH: Relining complete denture with minimum occlusal error J

Light jaw closure on the interocclusal
record is maintained with the
mandible in centric relation until the
final impression material has set.
A fast-setting impression plaster fills
the palatal opening in the denture.

Advantages:
1.The opening of the palatal portion will allow better seating of the
maxillary denture
2.The premade interocclusal record helps to position the dentures
Shaffer FW, Filler WH: Relining complete denture with minimum occlusal error J Prosthet
Dent 1971;25:366-370

Disadvantages
1.The possibility of moving the maxillary denture
2.The wax interocclusal record is not an accurate and safe record
3.Relining of both dentures at the same time.
Shaffer FW, Filler WH: Relining complete denture with minimum occlusal error J

TECHNIQUE B
• Centric relation Existing centric occlusion and intercuspation are
used as a means to seat the dentures.
• Denture preparation The same as for technique A.
Hansen NJ: Rebasing and relining complete dentures: A technique. Dent Clin North Am 1964;8:693-704

Special suggestion A large part of the palatal section is prepared to be
removed as follows:
•outline of the area should be indicated and deepened on the polished
surface up to half the thickness of the base.
•Holes are drilled at 5- to 6-mm intervals inside this groove.
Hansen NJ: Rebasing and relining complete dentures: A technique. Dent Clin North Am
1964;8:693-704

• This procedure is suggested for easy removal of the palatal portion
during packing and processing
Border molding Low-fusing modelling compound (green stick) is
suggested for border molding.
Impression: Impression wax is material of choice in this technique
1964;8:693-704

Disadvantages
(1) Wax impression material is difficult to work with and the possibility
of distortion exists.
(2) Errors of existing centric occlusion can produce an inaccurate
impression.
1964;8:693-704

TECHNIQUE C
Centric relation The same as in technique B.
Denture preparation The same as in techniques A and B.
Special suggestion The labial and palatal flanges of the denture are
perforated.
Christensen FT: Relining techniques for complete dentures. J Prosthet Dent
1971;26:373-381

Border molding The same as techniques A and B.
Impression No specific impression material recommended.
•Pt is cautioned to use light force and only tap the teeth together as
occlusal pressure may squeeze too much of impression material out
of dentures resulting in sore points.
Christensen FT: Relining techniques for complete dentures. J Prosthet Dent
1971;26:373-381

TECHNIQUE D
Centric relation The existing centric occlusion is used to seat the
maxillary denture.
Denture preparation The same as in the other techniques.
Jorden LG : Relining the complete denture. J Prosthet Dent 1972;28:637-641

Impression Plaster of Paris or zinc oxide eugenol is suggested for the first step of
impression making, and plaster of Paris for the second step (the palatal portions).

A BUCCAL GROOVE IS CUT INTO THE DENTURE AND
FILLED WITH WAX.
m

Disadvantage :- the existing errors of centric occlusion may produce
some pressure points and a faulty impression can result.
Jorden LG : Relining the complete denture. J Prosthet Dent 1972;28:637-641

Closed Mouth Relining Technique
—Mandibular denture

Technique E:- Gillis RR: A relining technique for mandibular dentures. J Prosthet
Dent 1960;10:405-410
Centric Relation:- Existing centric occlusion used to seat dentures.

Advantages:-
1) The loss of vertical dimension can be compensated for during
relining procedures.
Disadvantages:-
1) Time consuming.
2) The procedure for establishment of occlusal vertical dimension is
questionable.

OPEN-MOUTH IMPRESSION
TECHNIQUE

TECHNIQUE-F
BOUCHER CO: THE RELINING OF COMPLETE DENTURES. J PROSTHET DENT 1973;30:521-
526
Centric relation :-recorded with plaster
Denture preparation

Special suggestion The lower denture is prepared for the reline
impression
•Handel is formed over the lower anterior teeth
•Adhesive or masking tape is adapted over the polished surfaces of both
dentures and over the teeth.
Boucher CO: The relining of complete dentures. J Prosthet Dent 1973;30:521-526

Border molding If the flanges are inadequate, the borders should be
corrected with modelling compound.
Impression Zinc oxide-eugenol impression

Advantages
1.No occlusal interference during impression making.
2.It is possible to verify the centric relation record if necessary
3.The interocclusal record, which is made with quick-setting plaster, is a
reliable one.

Disadvantages
1.Although this technique seems simple, the performance of the
procedures is not easy.
2.This technique requires more clinical and laboratory time.

Tissue conditioner in dentures
Plastic stage
(tissue conditioner) Denture base responds to functional/
parafunctional stresses; fit is improved
(Few hours to few days)
Elastic stage Stress is cushioned;tissue
(tissue conditioner) recovery takes place
(1 to 2 weeks)
Firm stage Surface is similar to polymerized
(reline impression) resin surface, except it is vulnerable
to deterioration

Disadvantages:-
1) The materials often produce a chemical burn on the mucosa.
2) The result often was porous and developed a bad odour.
3) Colour stability was poor.
4) If the denture was not positioned correctly, the material could
not be removed easily to start again.

LABORATORY PROCEDURE FOR RELINING
► ARTICULATOR METHOD:-
Impression is made in the denture to be relined.
Denture impression is poured in dental stone.

Modeling clay adapted denture,
blocking out all the denture
surfaces,except occlusal surfaces
of the teeth.
Stone is placed on the lower
member and smoothed with
spatula. Denture is settled is
the stone mix.
www.indiandentalacademy.com

Cast is attached to the upper member of the
articulator with dental stone.
Modeling clay removed from
denture surface.

All impression material must be removed
from the denture.
Thin layer of resin must be removed
from the inferior of the denture
with the acrylic bur.

Borders are reduced 2-3mm with bur.
Frena notches are deepened with
Straight fissure bur.

Resin grindings removed with
stream of air.
Posterior palatal seal is placed in the cast,
unless provided in impression.

Paint cast with tinfoil substitute.
Mix autopolymerizing resin and place in
denture. Avoid air entrapment.

Place resin on cast and in border reflections
Denture is seated in indentations,
and articulator closed.

Relined denture cured in pressure container
at 15-20psi for 30min.
Relined denture removed
and examined for voids and
nodules.
Finished and polished.

► JIG METHOD:-
Stone index formed on lower member
of duplicator or jig.
Denture mounted on its cast in a reline jig
with stone and secured with locknuts

Porcelain denture teeth are removed from denture by
heating with alcohol torch or hot spatula.

Porcelain teeth replaced in their
indentations in the stone index
Adapt a layer of base plate wax to cast
and assemble the jig

Wax-up the denture teeth to base plate wax,
remove cast, flask and process with
heat cure denture base resin.
Cured denture replaced on jig to check
occlusion, then finished and polished.

►FLASK METHOD:-
Denture is half flasked
Silicone mold material painted
on denture and teeth.

Flask is opened.
Porcelain teeth Resin teeth

Cast and investing stone painted
with tinfoil substitute
Cured denture ready for
finishing and polishing.

REPAIR OF COMPLETE DENTUREREPAIR OF COMPLETE DENTURE

Tooth replacement Fractured dentures
Anterior teeth Posterior teeth
Non-separated parts
Separated parts
Missing parts
Denture repairDenture repair

► Complete dentures often fractures when in function or when
dropped onto a hard surface.
►The most common denture fractures are those along the maxillary
and mandibular midline.
►The repair of dentures is often handled as a laboratory procedure,
but a knowledge of preparation as well as the technical phase is
essential for successful repair.

CAUSES OF FRACTURE OF DENTURE
1) FRACTURE OF THE DENTURE BASE
► Improper mandibular occlusal plane
► High frenum attachments
► Occlusal morphology
► Beyli M.S. (1981) concluded that midline fracture of a denture base
was a flexural fatigue failure resulting from cyclic deformation of
the denture base during function. Buccally arranged upper
posterior teeth to the crest of the ridge will transmit flexing
component of forces to the midline of the denture during function
and leads to midline fracture.
► Denture base thickness: The denture lined with resilient denture
base liners are more susceptible for fracture due to excessive
reduction of the denture base to allow the space for liner material
will result in thinning of denture base and prone for fracture.
► Overdenture abutment too prominent.

METHODS FOR REPAIR
► Anterior Tooth Replacement:- Fractured tooth is
removed by grinding
with no. 8 round bur.
Care must be taken not
to perforate denture base
Labial gingival margin should
be left intact to preserve
esthetics.

Remove the resin from the lingual
aspect of the denture base .
Select a resin tooth
of same size and
shade and grind its
ridge lap for proper
positioning on the
denture.

Verify the tooth position and secure it in
position with sticky wax.
If the tooth position is
acceptable, pour a
plaster index or silicone
index onto the labial
surface of the tooth to
be replaced and on the
labial surfaces of adjoining
teeth on each side.

After plaster sets, the index and tooth
are separated and sticky wax removed.
Shallow indentations can be
placed in the ridge laps of the
tooth with a no. 6 bur to ensure
stronger repair.

Replace the index and
tooth on the denture,
and carefully paint the
autopolymerizing resin
to the lingual or palatal
prepared area,
allowing the resin to flow between
ridge lap and denture base.
Resin is added to build up slight
excess, which will be finished to
original contour after polymerizing.

Repaired denture is placed in a pressure pot of warm water, and
cured at 20 psi for 30min.

Remove the denture, and reduce the excess bulk with no. 8 bur and
resin is smoothed with mounted rubber point and repair is polished
with flour of pumice & handpiece mounted prophy cup.

Posterior Tooth Replacement:-
Mount the denture in an articulator
Remove the fractured resin tooth by grinding it with a no. 8 round
bur. Take care to preserve the facial
gingival margin of the denture base
and not to perforate the base.

Ridge lap area of
denture is hollow ground
and of the replacement
tooth is modified for the
correct placement of
tooth.
Close the articulator
and check the occlusion.
If correct, seal the
replacement tooth to
opposing tooth with
sitcky wax.

Paint the autopolymerising resin into the ridge lap area to seal the tooth to
the denture base.

Place the denture in a pressure container of warm water, and cure it for 30min. at 20
psi. Adjust the occlusion and polish the repair.

Repairing Fractured Denture:- ( Non-separated Fracture)
Examine denture to determine the
extent of the fracture. Gently flexing
denture will aid this determination, but
take care to prevent breakage.
If fractured denture self-approximates,
block the undercuts with clay,
and pour the repair cast.

Full cast is not necessary if the
fracture is small.
If undercut is there in
the region of repair,
silicone mold material
can be placed in the
undercut, resulting in
flexible cast permitting
removal of denture,

Remove the denture from the cast, and
widen the fracture line from beginning
to end with no. 558 bur.
Widened cut is beveled outwards
to increase bonding area.

Dovetails can be placed on the
palatal surface to further strengthen
repair joint.
Paint the stone cast with tinfoil
substitute and allow it to dry.

Denture is replaced on the cast carefully.
Repair resin is painted in groove,
taking care not to create voids.

Excess resin is built up Denture is secured to the
for finishing cast with a rubber band, and
cured in a pressure container for 30 min.
Cured denture is removed, finished and polished

► Denture Fractured into Two or More Parts
Examine the denture to determine that all pieces are present.
Assemble the pieces and lute them with sticky wax.

Modeling clay can be used to hold pieces while luting denture with sticky wax and
reinforcing with wood sticks before removing from clay.

Alginate can be used in
pronounced undercuts
in mandibular denture.

Remove the denture
from the cast. Bevel the
margins of each fragment
with bur and make grooves
and dovetail. Use wire
reinforcement to strengthen the
desired region desired.

Replace the denture on the cast, and paint autopolymerizing resin in each groove and
dovetail, and build up excess.
Secure the denture to the cast with plaster or rubber bands,
and cure in a pressure container of warm water for 30min. at 20 psi

SUMMARY
►Resurfacing and replacement of the denture base of a complete
denture is complicated procedure requiring astute clinical judgment
and skill if the therapy is to be successful.
►When the denture bases are under-extended, when there has been a
gross loss in the occlusal vertical dimension , and when centric relation
and centric occlusion do not coincide, then fabrication of new denture
would be treatment of choice.
►Relined or rebased dentures should be given the same care as new
dentures, and the patient should be recalled as often as necessary for
examination of the tissues and the jaw relations.

REFERENCES
Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.
Halperin A.R., Abadi B.J. : Repair of broken denture in resin undercuts. JPD, 1980;
44: 224-228.
Linear dimensional change of heat-cured acrylic resin complete dentures after reline
and rebase Edmond H. N. Pow, T. W. Chow, and Robert K. F. Clark (J Prosthet Dent
1998;80:238-45.)
Beyli M.S. : An analysis of causes of fracture of acrylic resin dentures. JPD, 1981;
46: 238-241.
David E.H. : Immediate stabilization of a broken maxillary denture. J.P.D. 1983; 50:
289-292.
Rudd K.D., Morrow M.R. : Dental laboratory procedures, complete dentures. 1st
edition 1986.
Sherif E.B., Carl R.S.: A metal insert to replace a fracture segment of a mandibular
C.D. JPD, 1989; 61: 250-251.
Winkler S. : Essentials of complete denture prosthodontics. 2nd edn, 2000.
Swenson’s Complete denture: 5th edition.
GONZALEZ J.B. AND LANEY W.R. : Resilient material for denture prosthesis. J
Prosth Dent. 1966 16: 438444.
Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.

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