Retention and Stability Flashcards
retention
resistance to vertical displacement
stability
resistance to horizontal displacement (function)
adhesion
physical attraction of unlike molecules for each other e.g saliva and denture base, saliva and mucous membrane
cohesion
physical attraction between similar molecules
what is a good baseline depth for a post dam
0.5mm
why are denture adhesives not recommended for all patients
denture adhesives move denture base slightly away from tissues compromising the adhesion/cohesion gained from saliva
if using a denture adhesive how much and where should it be placed
2 small blobs bilaterally at back and one at front
Name 3 different materials available for denture teeth
acrylic based
porcelain based (require retentive tag to adhere to base)
composite resin based
illuminant metameric failure
light source alters appearance meaning shades dont match under two varying lights
observer metameric failure
operator error results in wrong colour match
e.g colour blindness , genuine error
ask nurse for second opinion
Leon Williams Classification
states that tooth shape should match inverted face shape
no modern evidence supporting this theory
Frush and Fischer dentogenic concept
states that males should have square angular teeth and females curved and rounded
no modern evidence supporting this
in relation to the ridge , where should upper teeth be places
slightly buccal
Name 5 things to check at the denture try in stage
retention and stability
base extensions
Lip support
Incisal level
M idline
B uccal corridors
Occlusal planes
vertical dimension and FWS
position of teeth in comparison to soft tissues
speech
aesthetics
even occlusal contacts
how can you test for underextension during try in
hold tissues away, if underextended denture will drop
how can you test for an overextended denture during try in
over extended denture will drop when surrounding tissues are manipulated
how can speech be tested during try in of a denture
testing fricatives (f, v, s)
ask patient to say missisippi, the days of the week or count from 60 to 70
should upper or lower denture be inserted / removed first
lower should be recommended to be removed and inserted first
what makes up the pellicle layer
salivary proteins and bacterial products
what makes up denture debris
mainly plaque biofilm, food and calculus
what microorganisms might be found on a denture
bacteria - staphylococcus aureus, E.coli
fungi - candida
why does the environment under a denture favour candida
it is more acidic than rest of mouth
