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Relining & Rebasing

Presented by:

Dr. Rajesh Kumar

Guided by:

Dr. Suresh Sajjan

Principal, HOD

Dept Prosthodontics

INTRODUCTION

Definition • Reline:- The procedures used to resurface the tissue side of a denture with

new base material, thus producing an accurate adaptation to the denture foundation area.

• Rebase:- he laboratory process of replacing the entire denture base material on an existing prosthesis.

Treatment Rationale: 1. Loss of retention and stability.2. Loss of vertical dimension of occlusion.3. Loss of support of facial tissues.4. Horizontal shift of dentures: incorrect occlusal relationship.5. Reorientation of occlusal plane.

Diagnosis:

Indications:• Immediate dentures at 3-6 months after their construction.

• When the residual alveolar ridge have resorbed and the adaptation of the denture bases to the ridges is poor.

• When the patient cannot afford the cost of having the new dentures constructed.

• when the construction of new dentures with the accompanying series of appointments can cause physical or mental stresses, such as for geriatric or chronically ill patients.

winkler pg-342

General considerations:

1. OVD should be satisfactory.

2. Co should coincide with CR.

3. The patients appearance must be acceptable to the patient and the dentist. The size, shape, shade and arrangement of the artificial teeth must be satisfactory.

4. The oral tissue must be in optimum health.

5. The posterior limit of the maxillary denture is correct.

winkler pg-342

6. The denture base extensions are adequate.

7. The denture base extensions ensure distribution of masticatory forces over a large area as possible.

8. The interocclusal distance is correct.

9. Speech is satisfactory with the existing teeth arrangement.

10. There are no hard or soft tissue conditions that would preclude the technique, such as redundant tissue or severe bony undercuts.

winkler pg-342

Irritation of Peripheral Borders

Overextension

Correct eccentric excursions

Contraindications:1. When an excessive amount of resorbtion has taken place.

2. When abused soft tissue are present.

3. When the patient has TMJ problems.

4. Denture with poor esthetics or unsatisfactory jaw relations.

5. Dentures with major speech problem.

6. Severe osseous undercuts.

winkler pg-342

RELINING / REBASING

TECHNIQUES:-

Tissue Preparation:

Hypertrophic tissue should be surgically removed.

The oral mucosa must be free of irritations.

Removal of the dentures from the mouth during sleep is a must for several weeks before treatment commences.

The dentures should be left out of the mouth at least two to three days before making the final impression.

Daily massage of the soft tissues.

Denture preparation:1. Pressure areas on the soft tissue surface of the dentures

should be relieved.

2. Minor occlusal disharmony is corrected by selective grinding.

3. Small border inadequacies are corrected.

4. A correct posterior palatal seal area should be established before the final impression.

Principal pitfalls:

1. Do not increase the OVD.

2. Multiple even contacts(maximum intercuspation) must be

present in centric relation.

3. Do not allow the maxillary denture to move forward during

impression making.

4. Ensure that centric occlusion and centric relation are identical.

5. Ensure that accurate posterior palatal seal has been established.

6. Equal thickness of final impression material should be used.

winkler pg-343

Impression procedures:

1. Static impression technique.

Closed mouth Open mouth

2. Functional impression technique.

Functional Impression technique:

Plastic Stage :

Elastic Stage :

Firm Stage :

Tissue conditioner materials are used.

This material sets in three stages.

Denture base responds to functional/parafunctional stresses; fit is improved.

Stress is cushioned and tissue recovery takes place.

Surface similar to polymerized resin, except it is vulnerable to deterioration.

Precautions:• Pour the cast when the material reaches the firm

stage.• Peripheral or surface deterioration can occur. • Voids can occur during placement of material in the

denture.

Classification:

• Hard reline materials.

• Tissue conditioners.

• Soft lining materials.

Hard reline material:Chair side reline to the denture.Composition:Powder and liquidType I

Powder Polymer beadsInitiatorPigments

Poly methylemethacrylateBenzoyl peroxideInorganic salts

Liquid MomomerPlasticizer Chemical activator

MethylemethacrylateDi-n-butylphtalateTertiary amine

Type II

Powder Polymer beadsInitiatorPigments

Poly ethylemethacrylateBenzoyl peroxideInorganic salts

Liquid MomomerChemical activator

MethylemethacrylateTertiary amine

Properties:

Type II is less irritant than Type I.

Dimensional stability

Disadvantages:

Direct contact of the material in the oral cavity leads to irritation and sensitization.

Reline materials are often porous due to air inclusions.

Easily colonized by microorganisms including Candida albicans. Difficult to clean.

Increase in thickness of the denture and reducing the free way space.

This material should be considered as semi permanent solution to the problem of an ill fitting denture.

Tissue Conditioners:Tissue conditioners are soft denture liners. They are used to provide a

temporary cushion which prevents the masticatory loads from being transferred to the underlying soft and hard tissues.

Traumatized soft tissue due to wearing an ill fitting denture.

Applied on dentures of patients who have undergone surgery, extraction.

Stabilization of the immediate denture.

Used as a functional impression material.

Requirements:

• Should remain soft during use in order to maintain cushioning

effect.

• Material should be resilient, that the masticatory loads can be

absorbed without causing permanent deformation of the lining.

• When these materials are being used to obtain a functional

impression a degree of permanent deformation ender load is

required. This enables the impression of the soft tissue to be

altered during normal function.

Composition:

Manipulation:

Plastic stage - few hrs – few days.

Elastic stage - 1 – 2 weeks.

Firm stage - after 15 days.

Powder: Polymer beads Polymethyle methacrylate

Liquid: Solventplasticizer

Ethyle alcoholButylpthalyl butylglycolate

Soft Lining Materials:Soft or plasticized acrylic, vinyl polymers copolymers, as well

as natural and silicone rubber products have been used as soft denture liners.

Abused denture bearing mucosa, areas of severe undercuts, or congenital or acquired defects of the palate.

Some materials have an inhibitory effect on Candida albicans.

They are of *Temporary / mouth cured soft liners.

*Permanent / processed soft liners.

Desired Properties:

• High bond strength to the denture base.

• Dimensional stability of the liner during & after processing.

• Permanent softness or resilience.

• Low water sorption therefore reduced leeching of plasticizer and solvent into saliva.

• Color stability.

• Ease of processing.

• Biocompatibility.

Temporary Soft Lining Materials :

These are used for short periods (up to several weeks) to improve the comfort and fit of an old denture until it can be remade or permanently relined.

They are not as soft as tissue conditioners, but they retain their softness for a longer time.

They are also viscoelastic, give cushioning effect.

Oxygenating type of cleansers cause surface degradation and pitting of the material.

Permanent Soft lining Material:

Permanent soft lining materials are used for patients who cannot tolerate a hard base.

Patient with irregular mandibular alveolar ridge covered by a thin and a non resilient mucosa. For patient comfort and acceptance of the denture.

• Permanently soft.

• Cushioning effect.

• Prevent unacceptable distortions during service.

• Lining should adhere to the denture base.

• Non-toxic, non-irritant.

• It must prevent growth of harmful bacteria and fungi.

procedure:

•Reline material: Pink/white•Apply Vaseline (very slight coating)•Mix according to instructions

• Seat reline impression• Check on extensions

and patient border mold• Have patient close teeth

in CR gently!! 7-10 min

1. Remove denture from mouth

2. Trim conditioner

1. Evaluate peripheral roll

2. Can add on, grind add on

3. Functional impression technique: Tissue surface adaptation

• We must trim tissue conditioner

• Unacceptable

• Acceptable

•Examine after 1 week•Place posterior palatal seal after 1 week

Functional impression technique Mandibular Denture Reline

1 2

3 4

• After one week:– Borders corrected with

impression wax

Finished reline

Centric occlusion,Delivery

CLOSED MOUTH RELINE TECHNIQUE

Maxillary Denture

Static impression techniques

Shaffer FW & Filler WH Relining tech:

Centric Relation: modeling compound or wax.

Denture Preparation:

Special suggestion: A large portion of the mid palatal portion of the maxillary denture is removed

Border molding: low fusing modeling compound.

Impression: Zinc oxide euginol.

During the border molding and impression making, the patient closes lightly into the premade interocclusal record.

j prosthet dent 1971; 25: 366-370

1. Check extensions 2. Indicate amount of peripheral reduction required

3. Border Reduction 4. Tissue Conditioner preparation: Peripheral reduction + Tissue surface

Advantages:

Better seating of the maxillary denture and alleviate the increase in

vertical dimension pitfall.

The premade interocclusal records helps to position the dentures

during impression making and to orient the dentures on the

articulator.

The two step technique will reduce the possibility of moving of the

maxillary denture forward during the final impression making.

Disadvantages:

The possibility of moving the maxillary denture is still a major problem.

The wax interocclusal record

This technique does not suggest any solution for difficulties of relining both dentures at the same time.

5. Border Molding Completed

6. Palatal surface vented after B. M.

7. Seat denture until wash comes through vents 8. Final Impression

• Incorrect seating. Improper plane of orientation:– Not contacting teeth– Excess material– No vents

• Place ZnO wash• Have patient close in CR.

ZnO wash. Posterior palatal seal area using impression wax

Trim excess wax beyond anterior line

Reline final impression

Final Impression with PVS Final Impression with Rubber base

post palatal seal combination

• Identify in impression, before pouring it up.

Mandibular Denture Reline

Border molding completed

Complete Denture method-ZnO

Rubber Base Reline

Reline

Relined cast: Do not separate

Roughened border to blend new acrylic with old. Won’t show finishing line

After processing: Note junction line

Reline

Trimmed and polished

Hansen NJ relining method:Centric relation: Existing CO and intercuspation are used as a

means to seat the dentures.

Denture Preparation:

Special suggestion: A large part of palatal section is prepared to be removed as follows:

1. The outline area should be indicated and deepened on the polished surface up to half the thickness of the base.

2. Holes are drilled at 5 – 6 mm intervals inside the groove.

DCNA 1964; 8: 693-704

Border molding: low fusing modeling compound.

Impression: A wax that flows at mouth temperature, such as Kerr’s impression wax(lowa wax) is the material of choice in this technique.

The impression is made in two steps. The impression of the labial flange and the crest of the alveolar ridge between the canines is made as a second step.

Advantage:

The two step impression technique will reduce the possibility of extreme forward movementof the maxillary denture.

Disadvantage:

1. Wax impression material is difficult to work with and possibility of distortion exists.

2. Errors of existing centric occlusion can produce an in accurate impression.

Christensen method for relining:

Centric relation: Existing CO and intercuspation are used as a means to seat the dentures.

Denture Preparation:

Special suggestion:

The labial and palatal flanges of the denture are perforated.

Border molding:

The borders of the dentures are reformed to their functional contours by low fusing modeling compound.

j prosthet dent 1971; 26: 373-381

Impression : No specific impression material is suggested.

Advantages: Reduced movement of the maxillary denture during impression making.

Disadvantages:

The possibility of moving the maxillary denture is still a major problem.

This technique does not suggest any solution for difficulties of relining both dentures at the same time.

Relining by Jordan LG:Centric relation:

Denture Preparation:

Special suggestions: 1. The denture periphery should be shortened to create a flat border.

2. A large opening shoud be prepared in the palatal portion of the denture.

3. Adhesive tape is attached over the buccal and labial surfaces of both dentures 2mm away from the denture borders.

4. With a knife edge stone, a fairly deep groove should be cut into the buccal and labial surfaces of the dentures at the junction of the impression material and filled with molten base plate wax.

j prosthet dent 1972; 28: 677-641

Border molding:

not been suggested, but during impression making it has been emphasized that a slight amount of impression material should be left on the flattened borders.

Impression:

Zinc oxide euginol is suggested for the first step of impression making, and impression plaster for the second step (palatal portion).

Advantages:

The opening of the palatal portion will allow better seating of the maxillary denture and alleviate the increase in vertical dimension pitfall.

The two step technique

Disadvantages:

Though it has been suggested that the patient should not seat the denture by closing on it, the existing errors of CO may produce some pressure points and a faulty impression can result.

CLOSED MOUTH RELINE TECHNIQUE

Mandibular Denture

Gillis RR Relining technique:Centric Relation:

The existing CO(intercuspation) is used as a means to seat the mandibular denture during secondary impression. The occlusion is corrected during the establishment of a new occlusal vertical dimension.

Denture preparation: if required, not mandatory.

j prosthet dent 1960; 10: 405-410

Impression: Green stick compound for border molding, and zinc oxide euginol for making the secondary impression are suggested.

Advantages:

1. The loss of VD can be compensated during the relining procedures.

2. The error in CO can be reduced during the laboratory stages.

Disadvantages:

3. Time consuming, both laboratorial and clinical standpoint..

4. The procedure for establishing OVD is highly questionable.

OPEN MOUTH IMPRESSION TECHNIQUE:

Relining for maxillary and mandibular dentures at the same time.

After the maxillary and mandibular impressions are made, a new centric record is established.

All in single appointment.

CO Boucher’s technique:Centric relation:

Utilizing both dentures as recording bases, the jaw relation record is established after making the secondary impressions of both the dentures.

Denture preparation:

A posterior palatal seal is formed in modeling compound on the maxillary denture before any other changes are made on the tissue side of the denture.

j prosthet dent 1973; 30: 521-526

Special suggestion:

The buccal surfaces of the lingual flanges are ground

The lingual flange between the premylohyoid eminences is shortened by 1mm.

The labial flange between the buccal notches is shortened by 1mm.

Two grooves are cut on the buccal sides of the lingual flange to facilitate the removal of the retromylohyoid eminence after the cast is poured.

A modeling compound handle.

Adhesive or masking tape is adapted over the polished surface of both dentures, and the teeth.

Border molding: If flanges are inadequate, the borders should be corrected with modeling compound.

Impression:

Zinc oxide euginol is suggested i.e., exactly 15 sec after the denture has been placed in the mouth, the patient is asked to pull his lip down and to open his mouth wide.

Advantages: 1. Special trimming of the denture…2. A separate interocclusal record using already made impressions

as the recording bases will allow the operator to concentrate on recording the jaw relation.

3. It is possible to verify CR record.4. The interocclusal record, is reliable.

Disadvantages:

5. Although this technique seems simple, the performance of the

procedures is not easy.

6. This technique requires more clinical and laboratory time.

Winkler’s technique :• Minimum thickness of the tissue conditioning material The denture

is then inserted in the mouth with anterio-posterior relationship.

• The patient is instructed to tap the teeth together lightly, to position the denture, and to hold the teethe together lightly for 3 minutes.

• Then the patient is engaged in conversation or to read out loudly for additional 5 min.

• The basal surface is inspected. If any pressure spots seen, must be relieved and more material is added by brush on technique.

• Recalled after 15 days i.e. After the material has attained the firm stage.

• At this time a zinc-oxide euginol impression or a light bodied polysulfide rubber wash impression also can be made.

Laboratory Procedure:

• The impression is boxed and the cast is poured in artificial stone.

• Mount the cast on a semi adjustable articulator using a face-bow transfer record.

• Relate the mandibular denture to the maxillary denture, which is already on the articulator using an interocclusal record. Selective grinding procedure.

• The procedures of relining and rebasing are same until this stage. During the laboratory phase of a rebasing procedure, all of the old denture base is replaced by new material without changing the arrangement of teeth.

Soft liners

Insertion

Examine:•Peripheral extensions

• Pressure Indicator Paste (PIP)

• Ask the patient to bite on cotton rolls for 5 min.

• A new interocclusal record is used to mount the lower denture in centric relation.

• Mounting must be verified before adjusting the occlusion.

• occlusion must be perfected at the correct OVD using selective grinding procedure.

• Before dismissing the patient the occlusion is again checked.

Summary:

References:

• Winkler 2nd edition pg 341-351

• Heartwell 4th edition pg 425-430

• Boucher 12th edition pg 471-480

• Fenn 3rd edition pg 175-180

• Boucher: J Prosthet Dent 1973;30: 521-526

• Buchman: J Prosthet Dent 1952;2: 703-710

• Christensen: J Prosthet Dent 1971;26: 373-381

• Feldmann, Morrow: J Prosthet Dent 1970;23: 387-393

• Gillis RR: J Prosthet Dent 1960; 10: 405-410

• Hansen: DCNA 1964;8: 693-704

• Javid, Michael et al: J Prosthet Dent 1985;54: 232-237

• Jordan: J Prosthet Dent 1972;28:637-641• Klein, Broner et al: J Prosthet Dent;1985;54:660-664• McCartney: J Prosthet Dent:1981;45:564-567• Shaffer, Filler et al: J Prosthet Dent:1971;25:366-370• Smith,Lord et al: J Prosthet Dent:1967;18:103-115• Starke: J Prosthet Dent:1972;27:111-119• Tucker: J Prosthet Dent:1966;16:1054-1057

Thank you….