prosthodontics Flashcards
cawood + Howell classification of ridge form
I = dentate II= immediately post extraction III = well rounded, adequate height + width IV = knife edge, adequate height, inadequate width V = flat ridge form, inadequate height + width VI = depressed ridge form, basalar loss
define retention
capacity of denture to resist displacement away from tissues - attempt to remove against long axis
define stability
capacity of denture to resist movement whilst in contact with tissue - apply later finger pressure to dentures
how to achieve RCP
close with tongue up + back
for implant supported overdentures what else must you do on assessment with denture assessment
PPDs around implant
3 traumatic complications of dentures
- traumatic ulcer
- inflammatory hyperplasia (denture granuloma) - leave denture out
- extreme alveolar atrophy - flabby ridge
3 types of denture stomatitis
I = pin point hyperaemia + diffuse inflammation II = diffuse erythema of most denture baring area III = granular inflammation or inflammatory papillary hyperplasia
disadvantages of precision attachments
cost maintenance weaken denture base OH requirements increased load to abutments
2 types of stud attachments in ISOD
ball attachments + locators
magnets
why can c/c mislead into class III
maxillary absorbs labially first
mandibular absorbs lingual first
what is good wettability
being sufficiently fluid
2 non-elastic impression materials used
compound + ZnOE
2 elastic impression materials used
alginate + silicones
advantages + disadvantages to compound
\+ muco-compressive \+ readapted \+ combination with other materials \+ compatible with cast materials \+ used stock tray - technique sensitive - can't record undercuts - not as accurate - internal strains as low thermal conductivity - needs waterbacth - high TEX + shrinkage - poor dimensional stability
advantages + disadvantages of ZnOE
\+ accurate \+ dimensionally stable \+ adapted \+mucostatic - not for undercut - only sets in thin layer - need special tray - some patient allergic/burning - water + heat reduce setting time
advantages + disadvantages of alginate
\+ cheap \+ non irritant \+ stock or special tray \+ detailed \+ records undercuts \+ well controlled ST - not dimensionally stable - poor teat resistance + strength - less detailed than elastomers
how to record flabby ridge
cut whole out of special tray
used impression plaster
what is c/c denture base made out of
poly-methyl-methacrylate (PMMA)
3 types of porosity problems in acrylic denture
- contraction porosity - generalised
- gaseous porosity - localised
- granular porosity - white + frosty
how to avoid processing strains in acrylic denture
slow cooling
space left for alginate in major imps for partial denture
3mm
class I denture
bilateral free end saddle
class II denture
1 free end saddle
class III denture
bounded saddle
