Biomechanics Flashcards
For dentures that have free end saddle (Kennedy I and II), where isthe force transmitted?
To the abutment teeth as well as the mucosa
What can occur in free end saddles?
Rotational movement due to existence of 3 fulcrums
What are the 3 fulcrums/ planes rotation on a free end saddle?
Horizontal (frontal)
Saggital
Vertical (horizontal)
What is the horizontal plane?
Fulcrum that goes through the 2 main abutment teeth localised to the edentulous areas
What is the saggital plane?
Fulcrum line that goes through the occlusal rests of the more distal tooth to the residual ridge
What is the vertical plane?
Fulcrum line localised in the middle lingual line of the anterior teeth
What influences the magnitude of the force transmitted by the abutment teeth?
Length of the edentulous area
Quality of the residual ridge
Type of clasp
Occlusion
How does the length of the edentulous area influence the force transmitted by the abutment teeth?
The longer the edentulous area the greater the lever and the force applied to the abutment teeth
How does the quality of the residual ridge affect the force transmitted by the abutment teeth?
The worse the quality of the residual ridge and the mucosa (flabby ridge) the inner the forces will be transmitted to the abutment teeth
Mucosa underneath will not be strong enough to resist all the vertical forces
How does the type of clasp affect the force transmitted by the abutment teeth?
The type of retainer (clasp) changes the way in which the force is transmitted into the abutment, transmitting different magnitudes
Why is the RPI system so important?
Mesial rest seat…
The forces are directed more vertical against that tooth
How does occlusion affect the force transmitted by abutment teeth?
The different intensity of the force exerted by the occlusion of opposing teeth: natural, full denture, RPD, others, implies a different effect on the abutment tooth
