5. Repairs & Additions Flashcards
List some ccommon types of denture fracture (partials & Complete dentures)
Midline
Tooth detaches from denture base
Loss of flange
Acrylic saddle detaches from CoCr baseplate
Clasp fracture/bent
Why do dentures fracture?
Impact
Acrylic in thin sectin
Work hardening of metal
Parafunctional habits (Bruxists)
Occlusion - deep overbite
Soft linings
Denture processing problem - porosity
Bonding between tooth & base acryllic&CoCr
What is a simple repair?
Midline fracture of complete
If fractured pieces can be located together - disinfect and send to the lab–>no impression needed, cast poured, frac area removed and new acrylic area processed
What happens if a piece of the denture is missing?
Part of acrylic flange is lost
Impression taken w/ fractured denture in mouth
disinfected
cast poured and new acrylic processed into defect
What happens if there is loss of (an) acrylic tooth?
Easy if tooth is deboneded and Px has the tooth - can find the size and shade
Tricky if the patient lost the tooth - harder to find the size and shade - try to make the nearest fit
Repeat failure - ask why –> new prosthesis likely needed to be made
What may needed to be added on other repairs?
May need to add retentive tags - solder on tags
What sort of temp repairs can be done for a broken denture?
Self-cure acrylic
Cyanoacrylate glue - basically superglue
- Both can be done chairside
What are the diff types of strengtheners in denture repairs?
Wire mesh
Glass gibre mesh
Stainless Steel wire
Which denture - MAx or Mand - are strengtherners used?
The maxillary denture - they are used especially in Bruxist Px
What are the diff types of additions to dentures?
Immediate
Post-Immediate
Additional Retention for RPD
Which type of dentures are additions for?
Partials only dumbass - a complete denture is COMPLETE
What is an immediate addition?
When a tooth is lost after denture construction and a tooth is added on the day of XLA
What is a post-immediate addition?
When a tooth is lost after denture construction and at a later date the tooth is added
take an impression with the denture in place apres the tooth socket has healed
What is a ‘retention addtion’?
When retention is inadequate and a clasp is added to try to improve retention - usually a wrought stainless steel clasp —>0.5mm undercut
Nylon based dentures are flexible… what are some clinical issues with additions on these?
Adding to or repairing flexible dentures is virtually impossible due to weak bonding between tooth and nylon and generally longevity is short term - this is as teeth ‘ping’ off
The base flexes and there is limited ti no extension of the underbase tissues
It is also really easy to stain and hard to polish
BDS2 Q - WHAT IS the make up of acrylic?
Powder
- Polymer PMMA BEADS
- Initiator - Benzoyl Peroxide (.5%)
- Pigments - Salts of Cd/Fe or organic dyes
Liquid
- Monomer - MMA
- Cross linking agent (to Inc. strength)
- Inhibitor
Activator - ONLY IN SELF CURE
What is the Poweder:LIquid for acrylic?
2.5:1
Is the self cure process an endo or exotehrmic reaction?
Endo
What are some advantages of acrylic?
Cheap
Easy to add to or reline or repair
Technically easier to make
Aesthetic
What are disadvantages of acrylic?
Low impact resistance
Poor resistance to fracture fatigue - needs to be thick
Poor impact strength
Eater absorption and Candida growth
Allergy to residual monomer
Denture whitening
Risk to technicians - due to monomer inhilation
