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Flashcards in design principles of RPDs Deck (46)
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1
Q

what kind of support should be the aim with bounded saddles and why

A

tooth support
not likely to get as much alveolar absorption
teeth will move a little but the mucosa tends to move a lot

2
Q

what kind of support should be the aim with free end saddles

A

tooth and mucosa support

3
Q

where do you want the rest in a bounded saddle

A

want this as close as possible to the bounded saddle

4
Q

where do you want the rest in a free end saddle

A

on the mesial of the abutment tooth

if it was on the distal there is a risk the tooth would tip backwards

5
Q

what is the advantage of posterior tooth preparation

A

allows the rest seat to fit nicely on the tooth
doesn’t feel rough to the tongue
won’t affect the occlusion
usually easier to do it this way

6
Q

why should you be aware of metal crowns when preparing teeth

A

can be perforated

this means you would need to create a new metal crown for the patient at your own expense

7
Q

when do you not want support as close as possible to the saddle

A

If the last molar is tilted (angle of the mandible) then a rest seat on the mesial will cause the tooth to tilt so in this case the rest seat should go on the distal

8
Q

what do you look for in direct retention

A

triangular pattern of clasping

triangle cannot rock

9
Q

when can precision attachments be useful

A

when you dont have many teeth

10
Q

what clinical problems can arise with the RPI design

A

creates a small gap where food traps can occur
patients dont like these
not a good choice if the patient’s oral hygiene is not good

11
Q

what is bracing

A

lateral resistance to movement of the denture

12
Q

what is reciprocation

A

associated with newton’s third law = for every fore there is an equal and opposite one
if you don’t reciprocate the clasp then the tooth will move

13
Q

what are disadvantages of the plate connector

A

patient loses sense of taste
speech may be affected
can cause small food traps

14
Q

why do clinicians design the denture

A
They have seen the patient 
○ Tooth condition
○ Periodontal condition
○ Motivation 
	§ The success rate of denture depends on good oral hygiene and good dental care
○Cost
15
Q

what are alternative treatments to a RPD

A
  • no active treatment
  • fixed prostheses
    > conventional
    > resin-bonded
  • implants
16
Q

what are the 7 aspects of design

A
  1. saddles
  2. support
  3. retention
  4. indirect retention
  5. bracing / reciprocation
  6. connectors
  7. review and simplify
17
Q

what is the saddle area

A

the teeth being replaced

18
Q

name the classification system for saddles

A

kennedy denture classification

19
Q

what is kennedy class I

A

bilateral free end saddle

20
Q

what is kennedy class II

A

unilateral free end saddle

21
Q

what is kennedy class III

A

bounded saddle

22
Q

what is kennedy class IV

A

anterior bounded saddle crossing the midline

23
Q

what is support

A

the resistance of the denture to occlusally directed load

what is stopping the denture going through the mucosa

24
Q

name the classification system for support

A

craddock’s classification

25
Q

what is class I of craddocks classification

A

tooth borne support

26
Q

what is class II of craddocks classification

A

mucosa borne support

27
Q

what is class III of craddocks classification

A

combination of tooth and mucosa

28
Q

what is retention

A

resistance of the denture to vertical displacement (lifting away from the tissues)

29
Q

what are the methods of retention

A
  • clasps
  • soft tissue undercuts
  • adhesion
  • friction
  • path of insertion
  • precision attachments / implants
30
Q

what is indirect retention

A

resistance to rotational displacement

need to have things on both sides of the axis of rotation of the denture - need a balance

31
Q

what is reciprocation

A

prevents a clasp arm moving the clasped tooth

32
Q

what do major connectors do

A

connect all the components

33
Q

what do minor connectors do

A

connects rests, clasps and bracing arms

34
Q

what are the advantages of the bar design

A
gingival margins clear
gives good depth
comfortable for patient
simple design
doesn't affect taste
35
Q

what are the advantages of a mid palatal bar / strap

A

comfortable for patient

works well

36
Q

what are the advantages of the horse shoe design

A
  • works well

- keeps palate clear for patient

37
Q

if patient has a heavy bite which causes the denture to break how can this be resolved

A

rise the connector up higher on the prosthetic teeth anteriorly
metal backing means the denture cannot be broken due to the heavy bite

this q is v specific to the horse shoe design given as an example in this lecture x

38
Q

what are the advantages of a plate design

A

if the longevity of teeth is poor then it is easy to add new teeth onto the denture

can also extend the plate further back to give indirect retention and make denture more stable

39
Q

what are the disadvantages of a plate design

A

covers palate so taste will be affected

40
Q

name types of connectors

A
  • ring
  • bar
  • plate
  • spoon (every)
  • horseshoe
41
Q

what are the different types of lower CoCr bars

A
  • lingual
  • sublingual
  • dental
42
Q

what are the advantages of a flanged saddle

A
  • gives good retention
  • stops food trapping
  • appearance stays the same
43
Q

what are the advantages and disadvantages of gum fitted / open faced saddles

A

looks good initially

  • no flange
  • as resoprtion occurs there will be a gap
44
Q

what needs to be considered for tooth / mucosa support

A
  • periodontal condition of abutments
  • size and position of saddle / abutments
  • condition of supporting mucosa
  • occlusion / chewing capability
  • aesthetics
45
Q

what is involved in direct retention

A
  • clasps
  • engaging soft tissue undercuts
  • hydrostatic pressure
  • path of insertion
  • muscle control (more important for complete denture)
46
Q

what is included in the review stage of design

A

studying the design and deciding if you can make the design simpler, less fussy or have less components