PARTIAL DENT - Design for Cobalt Chrome Dentures Flashcards
give 4 principles of design for cobalt chrome dentures.
- avoid gingival coverage
- good support from denture
- rigid connector
- keep it simple
describe the 8 steps of design
SSRRRGC
- saddle
- support
- retention
- bracing/reciprocation
- indirect retention
- guide planes
- connector
- review the principles of design
give 3 aesthetic reasons of replacing a tooth
- aesthetics match with other teeth
- prevent over eruption
- phonetics
give 4 disadvantages of replacing a tooth
- contributes to plaque retention
- trauma to the tissues
- patient may not be tolerant
- cost
2 types of saddle, describe it
bounded saddle - bound to teeth on either side
free ended saddle - bound to one side
when replacing teeth, plaque is a disadvantage, what can plaque potentially lead to?
perio disease
caries
fungal infections
trauma can be a factor of tooth replacement, what can be traumatised?
soft tissues
pulp - lead to pulpal necrosis
why may the patient not be tolerant when replacing teeth?
gag reflexes
patient expectations may not be met
what does replacing teeth cost?
time and money
where do saddles extend to?
full extent of the denture bearing area
- to the sulcus functional depth
- lower arch - as far back as the pear shaped pad
- upper arch - as far back as hamualar notch
why do saddles extend so far?
to decrease pressure in the underlying mucosa
how is support provided?
rest seats
how are rest seats positioned on bounded saddles and free end saddles?
bounded
- on nearest surface of each abutment tooth
free saddle
- on the mesial aspect of the abutment tooth
why are rest seats placed mesially on the abutment tooth for free ended saddles?
- reduce torque on the abutment tooth
- aka reducing the force placed
when placing rest seats, what must be checked?
the occlusion
- if its tight, deep rest seat may be required
what can be made to assess the rest seat occlusions?
articulated study casts
what is used for retention?
clasps
how are clasps used to retain?
engage with the undercut
what is the undercut?
the area below the survey line
- the line of maximum bulbosity on a tooth
how is the retentive force determined?
by the horizontal depth of the undercut
what are the 3 types of clasp?
occlusal approach
- 3-arm
- ring
gingival approach
- I-bar
if there is no undercut on a tooth and we want to use that tooth for retention, how can we manage this?
add composite to gain an undercut
what must each retentive clasp arm include?
reciprocations
what is a indirect retainer and what does it aim to do?
a component which stops displaced rotation on the clasp when a free end saddle is pulled away from the mucosa
