Relining, Rebasing, and Repairing Flashcards
what is relining
adding new denture base material to the existing resin to make up for loss of tissue contact caused by resorption of the alveolar ridge
what is the easiest way to evaluate the space under the denture base
to place a thin mix of alginate in the denture base area, seat the RPD and maintain its position until set
how should the alginate be mixed to evaluate the intaglio surface of the RPD
mix with increased water-powder ratio to ensure minimal tissue displacement
- 1 scoop alginate powder mixed with 2 measures of hot water
when would the patient be considered a candidate for a reline or rebase
if at least 2 mm of alginate is present under the denture base or if the indirect retainer lifts 2mm or more
when would a rebase be considered instead of a reline
if the existing denture is short of ideal coverage
how could you evaluate support on distal extension of RPD
apply a seating force on the most posterior aspect of the denture base and observing an interior indirect retainer
if there is significant loss of support, the indirect retainer will:
lift from its rest seat
what is an indicator of the amount of space to be found under the denture base
the amount of space under the indirect retainer
a resin denture base is prepared for a reline impression by:
removing a uniform amount of denture resin from the intaglio surface of the denture base
the resin from the intaglio surface of the denture base should be removed for 2 important reasons
- space must be created so the impression material will not apply undue pressure to the underlying soft tissues
- the surface of the existing resin must be removed to eliminate potential contaminants and ensure a suitable bonding
what impression material should be used for relining in the case of mobile tissue on the crest of the ridge
a free flowing, zinc oxide eugenol impression material
what impression material should be used for a reline in the case of dense, firm denture base tissue
use any of the polysulfide rubber bases, polyethers, polyvinylsiloxanes and mouth temperature waxes
can tissue conditioning materials be used for relining? describe them
they can be although they offer no particular advantage and can easily distort the associated soft tissues
what is the most critical step in the reline procedure
the maintenance of the tooth framework relationship during the set of the impression material
should the patient be allowed to bring the teeth into contact during the impression making procedure
no - dentist must hold framework
what can small defects in the impression be corrected with
the mouth temperature wax
what should the dentist do to ensure that the desired support of the denture has been restored
rock the framework around its fulcrum
how should the mouth temperate wax be used
a small brush used to add it on then impression is returned to the mouth for 12 mintues
how does the lab reline the denture
- the prosthesis to be relined is located in one part of the flask while the replica of the edentulous ridge is found in the remaining part of the flask
intraoral relines are ______ to laboratory relines
inferior
why are chemically activated resins not to be used for an intraoral reline
they are poroud and will lack color stability
what is rebasing
a laboratory technique in which the bulk of the denture base is removed and replaced using new resin
rebasing results in a base of _____
uniform quality
why is rebasing technically complicated
the retentive meshwork is buried within the denture base often without sufficient relief beneath the mesh to allow for adequate bulk of new resin
what are the indications for a rebase
- denture bases do not extend to cover all the denture bearing tissues
- denture base has fractured
- denture base has become irreparably discolored
how is rebasing done by the dentist
- the denture resin is relieved and shortened to allow room for re-adaptation of the borders with modeling plastic
- when the border molding is complete the base is covered with a suitable impression material and the final impression is made
-make sure there are no defects- if there are fix with mouth temperature wax
what happens to denture after rebasing from the lab
the interface of new and old resin presents a line of demarcation but this is esthetic issue not structural
what is a remake
when both the denture base and the denture teeth are involved in a maintenance or repair situation the partial denture may need to be stripped of both teeth and denture base and remade
how are fractures repaired
- the pieces of the denture base are positively related and luted together using sticky wax
- a matrix is poured using stone. the matrix preserves the relationship of the denture base fragments
- the fracture line is opened using laboratory bur in a dental laboratory engine, and dovetails are prepared to provide mechanical retention
- chemically activated resin is added to the prepared fracture line
- the resin is slightly overbuilt to compensate for polymerization shrinkage
- assembly is placed in a heated pressure pot to complete the polymerization cycle
how do you repair tooth displacements
- the displaced tooth is repositioned in the denture base
- a matrix is fabricated
-diatorics are prepared in the ridge lap portion of the tooth to provide mechanical retention and the denture tooth is affixed to the matrix using sticky wax - denture base is relieved to permit the placement of at least 2mm of the repair resin beneath the prosthetic tooth
- the occlusal matrix and denture tooth are repositioned on the prosthesis
- chemically activated repair resin is placed into the prepared space using a small brush
- resin is slightly overbuilt to account for polymerization shrinkage
