Clinical Removable Prosthodontics Forth Year

1. Types of Refitting procedures :
1. Reline, resurfacing tissue side of the denture with ,gnew base material
2. Rebase, refitting of denture by complete replacement of the denture base material without
changing occlusal relations of teeth
3. Reconstruction, the denture is reassembled using original framework with new teeth & new base
material
RELINING is the resurfacing of a denture base with a new material to make it fit the underlying
tissues more accurately
REBASING is the replacement of a denture base with new material without changing occlusal
relation of the teeth.
The critical step in reline procedure is the maintenance of tooth framework relation during the set of
impression.
HOW TO DIAGNOSE DENTURES THAT NEED RELINING ?
In Distal-Extension Saddles :
Apply a seating force on the extreme distal end of the denture base & to see if anterior indirect
retainer lifts off its rest preparation as the denture rotates around a fulcrum line
In Bounded saddles :
Tissue changes beneath these bases did not affect RPD support, and so relining is done for the
following
1. unhygienic condition ( as trapping debris between RBD & RR
2. unsightly condition due to the space
3 pt discomfort 3. pt. associated with lack of tissue contact
RELINING AND REBASING RPDs
Types of Refitting procedures :
1. Reline, resurfacing tissue side of the denture with , g new base material
2. Rebase, refitting of denture by complete replacement of the denture base material without
changing occlusal relations of teeth
RELINING is the resurfacing of a denture base with a new material to make it fit the underlying
tissues more accurately
REBASING is the replacement of a denture base with new p material without changing occlusal
relation of the teeth.
In either case, a new impression is needed, using the existingdenture as an impression base for
either a closed-mouth or an open-mouth impression
The critical step in reline procedure is the maintenance of tooth framework relation during the set of
impression
HOW TO DIAGNOSE DENTURES THAT NEED RELINING ?
In Distal-Extension Saddles :
Apply a seating force on the extreme distal end of the denture base & to see if anterior indirect
retainer lifts off its rest preparation as the denture rotates around a fulcrum line
In Bounded saddles :

2. Tissue changes beneath these bases did not affect RPD support, and so relining is done for the
following
1. unhygienic condition ( as trapping debris between RBD & RR
2. unsightly condition due to the space
3 pt discomfort 3. pt. associated with lack of tissue contact
Indications of relining distal extension RPD :
1. Loss of occlusal contact
2. Loss of tissue support that causes rotation of RPD base when alternating finger
pressure is applied on either side of fulcrum
Need for relining is assessed by visual examination of the loss of support from supporting
tissues
1 Using thin mix of alginate.
2. Using finger pressure: applied to retromolar pad area of distal extension retainer 1 RPD base , if
indirect lifts 1- 2mm from its rest preparation
A thin mix of alginate ( minimum tissue displacement) used to evaluate the RPD base fit & to see if
reline is indicated
Slight pressure on denture base activates clasps & elevates superior border of lingual plate , results
in lack of planned contact . Relining is indicated
A manifestation of change in the supporting ridge to justify relining is the evidence of rotation about
fulcrum line with indirect retainers lifted from their seats as RPD base is pressed posteriorly
1. If occlusal contact is lost & rotation about fulcrum line is evident , relining is indicated g
2. If occlusal contact is lost without any evidence of denture rotation & with a satisfied denture base
stability , so reestablishing occlusion is needed rather than relining
Superior border of lingual plate & rests are in their planned relations to natural teeth in absence of
occlusal load
Indirect retainer is fully seated .
As pressure is applied to free-end base, indirect retainer is unseated ( a reline is needed )
FACTORS TO BE CONSIDERED IN CASE OF RELINING OR REBASING
1. Length of span
2. Amount of bone loss
3. Compressiblity of mucosa
4. Peripheral extension
5. Type of impression material used y
***IF RPD that needs refitting has abraded acrylic teeth, or broken or lost porcelain teeth, it
must not be relined or rebased
Lower RPD is removed to evaluate wax indentations. Absence of perforations in wax strips by
opposing posterior teeth . As such , relining & correction of occlusal discrepancies are needed
The difference between a reline & a rebase lies in the need to re-establish the borders of the denture
IMPRESSION TECHNIQUE
RPD base is prepared for reline impression by resin removal to have a space for impression material
& to ensure a suitable bonding surface

3. Reline impression with ZO-E ( mobile tissue on ridge crest ) OR with rubber base and /OR wax (dense, firm
tissues)
LABORATORY TECHNIQUE
1. Flask method
2. Duplicating device method (Hooper duplicator as used for CD reline procedures or other Metal
reline jig to preserve vertical & occlusal self-cured resin relations of RPD ( using self )
RPD to be relined is located in one part of the flask, replica of edentulous ridge in remaining part of
the flask. Flask can or can not be warmed according to impression material.
Secure positioning of RPD base to cast ensures no changes in VDO or in occlusal relations
Relined impression is mounted on a duplicating device ( self-cured resin is used )
Stone cast recording impression part & framework is fixed to reline jig ( cast is affixed to upper or
lower member )
Stone opposing cast is poured & secured to the other member of the jig.When stone sets, jig is
separated , to remove RPD from the cast to relief tissue surface & borders.
Self-cured acrylic resin is mixed & placed into the base
Framework placed on cast & arms of jig tightened to complete closure , covered with warm water & put in a
pressure pot at 20 psi / 15 minutes.
INTRAORAL RELINE
Adhesive tape is used to cover external surface of denture base ( to protect denture teeth). Mouthcured resin is mixed without trapping air intra-oral reline , acrylic resin extending finish line is
removed as in dough like state
Advantages of intraoral reline :
Quick procedure.
Disadvantages of intraoral reline :
1. Indicated only in temporary or transitional situation as chair side or mouth relining is inferior to lab
reline.
2. Material is porous & not color stable
REBASING
Rebasing is the replacement of a denture base with new material without changing occlusal relation
of the teeth.
base RPD is relieved to resin retaining elements . Modelling compound is used for border moulding
Rebasing is indicated when :
1. Denture base do not extend to cover all of the denturebearing tissue.
2. Denture base is fractured or being irreparable discolored
3. Framework good design is of & fits the teeth well.
4. When the denture is stained or discolored
When peripheral borders require extensive modification, or flanges need substantial alteration ,
rebase is preferred over reline
Under-extended form of lower RPD provides a reduced area of RR coverage that contribute to tissue
irritation. When denture base is properly extended , it will enhance support , stability, i retention
A sectional cast is poured against a rebase impression
Desired contours are re-established with baseplate wax

4. Rebase preparation needs most of existing RPD base to be removed by a large bur
RECONSTRUCTION
Indications :
1. When denture base is damaged beyond repair.
2. When the fit of the denture is not satisfactory.
3. Loss , RPD bases are burned away from underlying framework before starting reconstruction
RELINING NEW DENTURE :
Distal –extension base RPD is border molded ,impression is obtained with ZO-E impression
Relining Old Denture
As a result of bone loss ,relining is indicated to correct loss of fit
Distal extension saddle:
Occlusal plane not changed as opposing natural teeth not extruded
After reline or rebase, occlusion is equilibrated
Complete denture opposing RPD that requires refitting
refitting Oftentimes ,both dentures need refitting, one denture at a time
Mounting RPD against upper CD. Upper denture is mounted
through remount cast made after finishing & polishing of denture.
Occlusal registration in hard inlay wax supported by accurate
record bases Width of each cusp in . all excursive movements is recorded as continuous glossy
surface
Preparation for sprinkle-on record base technique.
out of undercuts & cast is coated with separating medium
Peripheral extent of base ( the same as peripheral extent of denture captured during impression
procedure for this altered cast ) is outlined with rope wax to contain resin
Cast is wetted with monomer & polymer resin is added to control thickness
Record base is completed when a uniform thickness is created providing strength & accuracy
Record base & framework are removed from the cast , finished and prepared for addition of occlusion
rim
Hard baseplate wax rim is most commonly used material to establish static occlusal relations
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 6. positioned, is difficult
7. Tissue irritation may be caused by lysis of the local monomer