RELING REBASING 1.ppt

8/11/2019 RELING REBASING 1.ppt

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Relines and Rebases

Improving the Adaptation of ExistingDentures


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Is the procedures used to resurface the tissue

side of a denture with new base material, thusproducing an accurate adaptation to the

denture foundation area.

Relining : is the process of adding new base

material to the tissue surface of an existing

denture in a quantity sufficient to fill the space

which exists between the original denturecontour and the altered tissue contour.


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Rebasing:

Is the process of replacing the entire denture

base material on an existing prosthesis. Only

the original teeth and their arrangement

remain.


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Rebase

Replacing entire denture base

Flasking, heat-cured acrylic

Usually porcelain teeth


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Determine Cause of Looseness

Pivoting on bony structures

- PIP

Occlusal interferences

- Tactile, articulating paper, remount

Inadequate posterior palatal seal

- Pull upward & outward on lingual ofcanines


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Relines Will Only Solve Retention

Problems Related to Denture Base

Adaptation

Retention problems must be diagnosed

as to their cause


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Processed or chairside

Impression or functional technique

Hard acrylic or resilient

Permanent, temporary

Complete or partial dentures

Types of Relines


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Processed Acrylic Permanent

Complete Denture Relines

Make impression for least stable

denture first

Easier to stabilize the other denture

Reference for occlusion & vertical

dimension


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Adjust Occlusion

Obtain stable occlusal contacts

Remount & adjustment may be required

Assess need for tissue conditioning


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Remove Tissue Undercuts

Allows impression to be removed fromcast without breaking cast or denture


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Clean the Denture


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Border Mold

Relieve borders 2 mm short of vestibule

Border mold with compound

Maxillary posterior border at vibrating

line (indelible stick)


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Reduce Tissue Base

1 mm if acceptable interocclusal distance Use guide grooves

If interocclusal distance is excessive, relief

may not be required

Perforate denture with #4 round bur


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Impression MaterialPolyvinylsiloxane

Ease of use

Cleaning, removal from undercuts

Requires adhesive carried to the external

surface of denture borders


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Impression Procedure

Load carefully

Excessive material canreduce freeway space

Dry tissues


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Impression Procedure

Seat denture anteriorly

Slowly rotate posterior into place

Ensure denture is not too far forward


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Evaluate Impression

Trim impression to posterior border

Place / mark the posterior palatal seal

Check retention, extension, periphery

Remove excess (occlusal, facial etc.)

Ch k l ti i t ll


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Check relations intraorally

Send to lab for processing


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Deliver ASAP, usually next clinic

Same day in practice, if possible


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Impression TechniqueDisadvantages

Possible alteration in VDO, occlusion,

facial support

No chance to test retention and comfort

under function


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Functional Relines

(Lynal, Visco-gel)

Similar procedure

Minor variations


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Functional Relines

Material requires greater thicknessfor accuracy

Usually need to reduce denture to

allow for thickness


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Variation in Accuracy of Materials

(Visco-gel> Coe-Comfort)


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Lynal

10 ml powder : 2 ml liquid, mix 30 sec

If borders short or too thin, add more

powder for increased viscosity

Thicker consistency can be formed into a

3 - 4 mm rope and placed around borders


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Remove Excess

Reduce material on flanges with

HOTscalpel or knife Remove from teeth, oral surfaces

Patient wears reline home


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Patient Returns in 24-48 Hours

A cast is poured within 2 hours

Otherwise, accuracy compromised


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Functional Impression

Disadvantages Dimensional stability variable

Patient care

Pouring of casts

Can' t significantly increase borders

Do not use simultaneously as a tissue

conditioner


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Partial Denture Relines

Similar procedures

Ensure rests, direct and indirect

retainers are fully seated

Seat with pressure over the rests,

NOTthe distal extension bases


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Partial Denture Relines

Allow no impression material under

rests or guiding planes

If so, remake impression


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Partial DentureClinical Remount

If required, a new cast must be made

Make an alginate impression with the

RPD in place


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Partial Denture

Clinical Remount

Block out undercuts on the

framework while RPD is in the

impression

Pour the model with the partial

denture in place

RELING REBASING 1.ppt

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