Relining, Rebasing, and Repairing

Question 1

what is relining

Answer 1

adding new denture base material to the existing resin to make up for loss of tissue contact caused by resorption of the alveolar ridge

Question 2

what is the easiest way to evaluate the space under the denture base

Answer 2

to place a thin mix of alginate in the denture base area, seat the RPD and maintain its position until set

Question 3

how should the alginate be mixed to evaluate the intaglio surface of the RPD

Answer 3

mix with increased water-powder ratio to ensure minimal tissue displacement
- 1 scoop alginate powder mixed with 2 measures of hot water

Question 4

when would the patient be considered a candidate for a reline or rebase

Answer 4

if at least 2 mm of alginate is present under the denture base or if the indirect retainer lifts 2mm or more

Question 5

when would a rebase be considered instead of a reline

Answer 5

if the existing denture is short of ideal coverage

Question 6

how could you evaluate support on distal extension of RPD

Answer 6

apply a seating force on the most posterior aspect of the denture base and observing an interior indirect retainer

Question 7

if there is significant loss of support, the indirect retainer will:

Answer 7

lift from its rest seat

Question 8

what is an indicator of the amount of space to be found under the denture base

Answer 8

the amount of space under the indirect retainer

Question 9

a resin denture base is prepared for a reline impression by:

Answer 9

removing a uniform amount of denture resin from the intaglio surface of the denture base

Question 10

the resin from the intaglio surface of the denture base should be removed for 2 important reasons

Answer 10

• 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

Question 11

what impression material should be used for relining in the case of mobile tissue on the crest of the ridge

Answer 11

a free flowing, zinc oxide eugenol impression material

Question 12

what impression material should be used for a reline in the case of dense, firm denture base tissue

Answer 12

use any of the polysulfide rubber bases, polyethers, polyvinylsiloxanes and mouth temperature waxes

Question 13

can tissue conditioning materials be used for relining? describe them

Answer 13

they can be although they offer no particular advantage and can easily distort the associated soft tissues

Question 14

what is the most critical step in the reline procedure

Answer 14

the maintenance of the tooth framework relationship during the set of the impression material

Question 15

should the patient be allowed to bring the teeth into contact during the impression making procedure

Answer 15

no - dentist must hold framework

Question 16

what can small defects in the impression be corrected with

Answer 16

the mouth temperature wax

Question 17

what should the dentist do to ensure that the desired support of the denture has been restored

Answer 17

rock the framework around its fulcrum

Question 18

how should the mouth temperate wax be used

Answer 18

a small brush used to add it on then impression is returned to the mouth for 12 mintues

Question 19

how does the lab reline the denture

Answer 19

• 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

Question 20

intraoral relines are ______ to laboratory relines

Answer 20

inferior

Question 21

why are chemically activated resins not to be used for an intraoral reline

Answer 21

they are poroud and will lack color stability

Question 22

what is rebasing

Answer 22

a laboratory technique in which the bulk of the denture base is removed and replaced using new resin

Question 23

rebasing results in a base of _____

Answer 23

uniform quality

Question 24

why is rebasing technically complicated

Answer 24

the retentive meshwork is buried within the denture base often without sufficient relief beneath the mesh to allow for adequate bulk of new resin

Question 25

what are the indications for a rebase

Answer 25

• denture bases do not extend to cover all the denture bearing tissues
• denture base has fractured
• denture base has become irreparably discolored

Question 26

how is rebasing done by the dentist

Answer 26

• 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

Question 27

what happens to denture after rebasing from the lab

Answer 27

the interface of new and old resin presents a line of demarcation but this is esthetic issue not structural

Question 28

what is a remake

Answer 28

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

Question 29

how are fractures repaired

Answer 29

• 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

Question 30

how do you repair tooth displacements

Answer 30

• 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