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
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