Relining , Rebasing and Repair of RPDs

Reline

Addition of Material to the tissue side of a

denture to improve its adaptation to the

supporting mucosa.

Resurfacing the tissue surface

Jig used to maintain vertical dimension &

occlusal contacts with cold-cure acrylic

Or

Reprocessing with heat cure

Jig used to maintain vertical dimension & occlusal

contacts with cold-cure acrylic

Reprocessing with heat cure

Rebase

Replacement of the entire denture base material

to improve its adaptation to the supporting

mucosa

Reline Indications

Loss of retention

Instability

Food under denture

Abused mucosa

In addition to improve lack of fit to the

supporting tissue

Relining may be combined with

Improving border extension (depth and

/or width labially / buccally / lingually,

length posteriorly) or provision of a

post dam. It cannot correct errors in tooth

positioning (vertical and / or horizontal)

Reline: General Considerations

Optimal tissue health

Reasonable CR/CO

Adequate vertical dimension

Adequate peripheral extensions

Also relining cannot be used when

No free way space

Lack of balanced occlusion and articulation

Non-alignment with optimal denture space

Incorrect contour for neuromuscular control.

Patient and denture pre-requisites

for relining

1. Tissues must be in normal healthy state

2. The denture must be able to be stabilized by border refining

3. There must be reasonable centric occlusion in harmony with centric relation

4. There must be at least correctable rest vertical dimension and occluding vertical dimension

5. Absence of speech defects (possibly whistling can be corrected)

• Processed or chairside

• Impression or functional

technique

• Hard acrylic or resilient

• Permanent, temporary

• Complete or partial dentures

Types of Relines

Relining

Both

Hard and resilient

Hard relining

Aims: Provides even contact between the

impression surface of a denture and its

supporting tissues, thereby improving

retentive forces and support.

Techniques of liner Both

Hard and resilient

Chair side relining technique

Conventional relining technique

RPD Relines

1. Similar to an altered cast impression

2. Materials of choice are Zinc Oxide wash or impression wax

3. Shoe extension must be cleaned of impression material

4. If reline is to be sent to dental lab. some distance away, then an over impression must be taken with reline in place in mouth and cast poured

5. If reline is sent to local lab., then a wax impression is ideal

Chair side (Direct relines): Indications

1. Where no longer than 6 weeks is

required

2. Around overdenture abutments

3. Border additions

4. RPD base areas

Direct Relines: Contraindications

1. For long term service (deteriorate in oral environment)

2. Poor impression materials, which are not accurate and cause tissue displacement

3. Difficulty of material in adhering to denture base

4. Tissue surface is rough and presents porosity

5. Color stability is of short duration

6. If denture is not properly positioned, correction is difficult

7. Tissue irritation may be caused by lysis of the local monomer

Resilient soft linings

Aims : to absorb the impact energy of masticatory forces and distribute it more evenly

over the supporting tissues.

Indications of soft lining

It is most effective when used over

corticated bony elevations.

Use to improve retention by engaging

undercuts.

Not advised where mental neurovascular

is superficially placed.

Disadvantages of soft linings

Tend to peal off the hard acrylic denture

base (acrylic material adhere better).

Difficult to adjust (acrylic materials more

easily altered).

Porous, tending to absorb fluids ) with

resultant swelling and bad odour) due to

harbor bacteria and fungi

Disadvantages of soft linings

Need more thickness to be effective this may be weaken the denture specially the lower.

Rapidly deteriorate

some patients can become habituated to such linings and cannot be satisfy with hard tissue surface.

Rub the oral mucosa since they deform under masticatory pressure.

Resilient lining after 11 months in service

Silicon lining showing colonies of Candida

Conventional relining technique

Reline of New RPD

Clean the Denture

before relining

Reline of old RPD

Remove Tissue Undercuts

Allows impression to be removed from cast without breaking cast or

denture

Open mouth technique for relining

Put your fingers on main occlusal rests

and indirect retainer

Reline of denture

Functional impression

Occlusal adjustment of finished denture

Materials used for Reline RPD’s

ZnO wash

Wax wash

Relining with wax

Repairs and additions to partial dentures

Accidents or careless handling of the denture

by the patient might result in a need for repair.

The following are some of the repair

procedures which might be necessary in these

cases.

Broken clasp arms

The most common type of repair is the

replacement of a broken clasp arm.

Breakage may result from repeated

flexure into and out of too severe undercut

A broken retentive clasp arm

Regardless of its type, may be replaced with a

wrought-wire retentive arm embedded in a resin

base or attached to a metal base by electric

soldering.

Broken retentive arm of

A circumferential clasp

Fractured direct retainer and replaced by

wrought wire

Repair by electric soldering between minor and major

connectors ( Repair is not strong as the original)

Electric soldering

machine soldering between

clasp and base

Laser welding to repair broken clasp

Laser welding machine

One of the most common partial denture repairs is to replace or add a new tooth to a pre-existing partial due to tooth loss. Laser welding a wrought wire loop to the major connector for retention of an acrylic tooth saves time; in fact, this reliable technique allows repairs to be accomplished

Retentive loop addition

Welding the meshwork

To major connector

Wrought Wire retentive arm attachment

Laser weld to

framework mesh or

bead

arm attached to a metal base by

electric soldering.

Loss of an additional tooth

If for some reasons a tooth is to be extracted,

the addition of such a tooth to the partial is

usually a simple procedure where the bases are

made of resin. When the base is made of metal

the procedure is more complex and necessitates

either casting a new component or adding it by

soldering, or creating retentive elements for the

attachment of resin extension carrying the added

tooth.

A new component or adding it by soldering to

replace lost tooth

Cast weld

Repairs a broken continuous clasp and lingual bar by laser welding

Broken Occlusal Rests

Breakage of an occlusal rest almost always occurs at

the point where it crosses the marginal ridge, due to

weakness at this point. Improperly prepared occlusal

rest seats are usually the cause of such weakness.

In case of broken occlusal rest it is always best to replace

the whole clasp assembly.

BROKEN OCCLUSAL RESTS

Breakage of an occlusal

rest of a roach clasp Replace the whole clasp assembly.

Any question