denture processing Flashcards
Which casts require relining?
- new dentures (lose adaptation
- old dentures (bone resorption)
What is rebasing?
replacement of entire denture base with a new material
relining and rebasing should be done without changing which relationship?
occlusal
When is relining indicated?
when denture loses its adaptation to tissues due to bone resorption while other points (occlusion, aesthetics, occlusal vertical dimension and denture base material) are all satisfactory
What is the procedure of relining of complete denture?
- remove the denture out of the patient’s mouth for 48 hours to give time for the mucosa to rest
- reduce the denture borders 2mm (to allow the flow of impression material to reach
the depth of vestibule) - remove undercuts from the fitting surface of the denture.
- take impression while the patient is closing in centric occlusion under closed mouth technique (to preserve occlusion)
- make boxing and pour the cast
- make flasking
- throw away the impression material to make space for new acrylic resin
- pack heat cured acrylic resin in the place of impression material
- curing (45° for 20 minutes) (long curing cycle)
- deflasking then laboratory remounting
- finishing and polishing
If both upper and lower dentures need to be relined, which one is relined first and why?
lower denture as upper denture is supported by the palate but lower denture is not supported
What to do if vertical dimensions are not correct?
remake
What are the steps of rebasing?
- remove the denture out of the patient’s mouth for 48 hours to give time for the mucosa to rest
- reduce the denture borders 2mm and drilling 3 holes through the palate to allow the flow of impression material to reach the
depth of vestibule - remove undercuts from the fitting surface of the denture
- take impression while the patient is closing in centric occlusion under closed mouth technique to preserve occlusion (to preserve VDO)
- make boxing and pour the cast
- mount the cast and the denture on Hooper articulator or simple hinge articulator (to preserve occlusion and VDO)
- grind the denture base and throw it
- make new denture base from wax
- flasking → wax elimination → packing of acrylic resin → curing → deflasking →
laboratory remounting → finishing and polishing
When is rebasing done?
when denture contains cracks but occlusion must be right
What does polishing of denture consist of?
making denture smooth and glossy without changing its contour
When is finishing and polishing done?
after laboratory remounting (processing)
What is the procedure of wax elimination?
placing flask in hot water
What happens before wax elimination?
flasking
What happens after wax elimination?
acrylic resin packing
What happens after flasking is done?
wax is flushed out with hot water
How is the cast remounted?
cast has indices or v-notches
When is laboratory remounting done?
after processing and before finishing and polishing
Who does the laboratory remounting?
lab technician
Why do we remount the cast?
refining of occlusion