Relines and Rebases

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Relines and Rebases

• Improving the Adaptation of Existing Dentures

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Rebase

• Replacing entire denture base
• Flasking, heat-cured acrylic
• Usually porcelain teeth

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Reline

• Resurfacing the tissue surface
• Jig used to maintain vertical dimension
  occlusal contacts with cold-cure acrylic
• Or
• Reprocessing with heat cure

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Indications

• Denture no longer fits residual ridge
• Retention, stability are lacking
• PLUS
• Occlusion is acceptable
• Vertical dimension is acceptable
• Denture teeth/gingival contours acceptable

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Contraindications

• Complaints of a loose denture
• DOES NOT,
• in itself, constitute evidence of
• a lack of fit and stability

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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 of canines

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Evaluate Cause of Looseness

• Coronoid interferences
• Side to side movements, PIP
• Flanges overextensions
• Pull on the cheeks, lips, patient move tongue
• Tight pterygomandibular raphe

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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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Types of Relines

• Processed or chairside
• Impression or functional technique
• Hard acrylic or resilient
• Permanent, temporary
• Complete or partial dentures

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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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Impression Technique

• Difficult to reline without
• Encroaching on interocclusal space
• Displacing the supporting tissues
• Altering occlusal contacts
• USE CARE

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Positioning the DentureOVD Occlusion
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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 from cast
  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 Material Polyvinylsiloxane

• 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 can reduce 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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Verifying Position

• Patient closes lightly until first contact
• If occlusal interdigitation is poor, physically
  move denture
• Maintain position until set

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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.)

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Check relations intraorallySend to lab for
processing
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Deliver ASAP, usually next clinic Same day in
practice, if possible
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RemountAdjust Occlusion
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Impression Technique Advantages

• Only two appointments needed
• Tissues are captured at rest (less possibility
  of distortion)
• Allows for greater extension of peripheries
• Allows placement of functional posterior palatal
  seal

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Impression Technique Disadvantages

• 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

• Cannot extend borders greater than 4 mm
• Distorts too easily
• Grossly under extended, use impression technique

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Functional Relines

• Material requires greater thickness for accuracy
• Usually need to reduce denture to allow for
  thickness

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Variation in Accuracy of Materials

• (Visco-gelgt 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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Lynal

• For tissue base, mix as per instructions
• Place intraorally
• Remove excess with cotton swab prior to set

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Set time 8-10 minute

• Lightly border mold
• During setting, allow patient to
• Talk
• Swallow
• Lightly occlude

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Remove Excess

• Reduce material on flanges with HOT scalpel 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 Advantages

• Functionally molds peripheries
• Ability to assess patient comfort and retention
  prior to reline proper

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Functional Impression Disadvantages

• Variability of materials, handling
  characteristics
• Resiliency masks overextensions which can
  subsequently irritate, when converted to acrylic
  resin

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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, NOT the
  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 Denture Clinical 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