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SP15 Partial Dentures > Retainers > Flashcards

Flashcards in Retainers Deck (78)
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1
Q

This engages an abutment tooth to resist displacement of the RPD away from the tissues; keeps the RPD in place

A

direct retainer

2
Q

This type of direct retainer is cast or attached totally within the contours of the abutment tooth

A

intracornal

3
Q

What are the two types of intracoronal retainers

A

key and keyway

4
Q

What is the ONLY advantage of an intracoronal retainer

A

esthetics

5
Q

What are the 5 disadvantages of an intracoronal retainer

A
requires casting
complicated clinical/lab
difficult to repair
additional expense
may require the splinting of several teeth
6
Q

This type of direct retainer resists displacement using components placed on or attached to the external surfaces of the abutment tooth

A

extracoronal

7
Q

This is the type of extracoronal direct retainer that we will be using for this course

A

clasp type retainer

8
Q

What are the four parts of a basic clasp

A

rest
retentive arm
reciprocating arm
guiding plate

9
Q

Where would you like the arms of a cast circumferential to fall

A

in the middle 1/3 of the hight of contour

10
Q

This is used to determine the path of insertion, HoC, and under cut

A

surveyor

11
Q

What is the function of the occlusal rests

A

in order for the partial to not seat into the tissues and irritate them

12
Q

This is used as a resistance to vertical dislodging forces

A

retentive arm

13
Q

This counteracts the retentive force of the clasp

A

reciprocal arm

14
Q

Which arm, the retentive or reciprocal, goes beneath the height of contour in a CC clasp

A

retentive arm

15
Q

Resistance to vertical seating forces is provided by what

A

the occlusal rests

16
Q

In which tooth surface is it best to keep rests in

A

enamel

17
Q

What is the best type of rest for anterior teeth, specifically canines

A

cingulum rest

18
Q

What is the best type of rest for anterior teeth, especially when using the cingulum is not practical

A

incisal rest

19
Q

What is the indication for a CC clasp

A

Kennedy class III

20
Q

What is the CC clasp excellent at

A

support
bracing
retentive properties

21
Q

Where is the location of the occlusal rest of a CC clasp

A

adjacent to the edentulous space

mesial or distal

22
Q

Where is the location of the guide plate of a CC clasp

A

adjacent to the edentulous space

mesial or distal

23
Q

Where is the location of the retentive clasp of a CC clasp

A

usually on the buccal

wherever the undercut is

24
Q

Where is the location of the reciprocating arm of a CC clasp

A

usually on the lingual

opposite of the retentive clasp

25
Q

When is an embrasure clasp indicated

A

for a Kennedy class II, III or IV with no modification spaces on opposite of the arch to aid in clasping

26
Q

Why are double occlusal rests needed with an embrasure clasp

A

to avoid wedging

27
Q

What are the six requirements for every direct retainer or clasp assembly

A
support
stabilization
retention
adequate encirclement
reciprocity
passivity
SARRPS
28
Q

This provides stabilization and unites the major connector with other components such as rests

A

minor connector

29
Q

This component of the clasp provides stabilization

A

guide plates

30
Q

What is adequate encirclement

A

greater than 180° encirclement around the tooth; engaging more than half the tooth

31
Q

What is the passivity of the partial

A

there should be no active force on the tooth when the clasp is in place

32
Q

This is the component of the RPD which contacts the oral much and to which the teeth are attached; made of pink acrylic and provides support

A

denture base

33
Q

What are the three denture base retention designs

A

open lattice
mesh
nailhead (butt acrylic tooth)

34
Q

Which denture base retention is used most frequently

A

open lattice denture base

35
Q

What is the description of open lattice denture base retention

A

two longitudinal struts extending along the edentulous ridge, one strut buccal and the other lingual to the crest of the ridge
one strut between each replaced tooth (like the edentulous space)

36
Q

A mesh denture base is thin, which would this be indicated

A

when there is not a lot of inner arch distance

37
Q

In the bead, wire, or nailhead retention the cast is formed directly on the ridge so what occurs

A

so there is no acrylic packed underneath; making relining impossible

38
Q

How is retention gain via the bead, wire, or nailhead retention base

A

by the metal projection on the metal surface

39
Q

When is a bead, wire, or nailhead indicated for a butt acrylic tooth

A
in 1 or 2 teeth in the anterior
kennedy class III or IV
40
Q

The acrylic resin joins the metal at what

A

at the butt joint (finish line) to prevent over thinning of the acrylic

41
Q

Where are the internal and external finish lines

A

internal on the tissue side

external on the outer aspect

42
Q

Butt acrylic teeth are not indicated for what

A

Kennedy class I or II

43
Q

What are the characteristics of the external finish line

A

should be sharp, definite, and slightly undercut to adhere to resin
angle or finish line with major connector should be less than 90°

44
Q

What are the characteristics of the internal finish lines

A

formed from the margins of the relief wax, used over edentulous ridge to create space for the acrylic

45
Q

This provides resistance which prevents the partial from being displaced toward the tissue; provided by the rests

A

support

46
Q

This provides resistance to horizontal components of force; provided by the minor connector

A

stabilization

47
Q

This provides resistance to dislodgment in a vertical or occlusal direction; provided by the retentive arm of the direct retainer; engaging the undercut

A

retention

48
Q

This balances or counteracts the retentive force of the clasp; provided by the reciprocal arm

A

reciprocity

49
Q

This is a component of a removable partial denture, located on the opposite side of the fulcrum line, that assist the direct retainer in preventing displacement of a denture base through mechanical leverage; prevents the lifting with sticky foods

A

indirect retainer

50
Q

What is the purpose of the 2x2 tissue stop

A

prevents framework distortion during packing and processing of the acrylic resin

51
Q

This type of direct retainer originates below the height of contour

A

infrabulge direct retainer

52
Q

This type of direct retainer originates above the height of contour

A

suprabulge direct retainer

53
Q

Kennedy class III uses which clasp design

A

CC clasp

54
Q

Kennedy class I and II uses which clasp design

A

RPI and RPA

55
Q

When is a wrought clasping system (combo included) indicated

A

when reduced force is desired upon the abutment; endo teeth and loss of bone support

56
Q

This type of class is sometimes used when the available undercut is on the mesial lingual or mesial buccal of mandibular molars

A

ring clasp

57
Q

Which clasp systems have a 0.02 undercut

A

wrought and combo clasp

58
Q

What are four considerations when selecting the path of insertion

A
  1. amount of tooth structure to be removed on guiding surfaces
  2. correct location of undercut for clasping system selected
  3. absence of tissue undercuts that will prevent the seating of the RPD along the path of insertion
  4. patient’s ability to place the RPD along the path of insertion
59
Q

Why must RPD clasps be configured regarding a Ken I or II

A

due to the lever system; rotation occurs due to differences between the tissue and the PDL

60
Q

How can you counteract the class 1 lever system on a Ken I or II

A

move the occlusal rest to the mesial

61
Q

What are the components of the RPI clasp

A

R - mesial rest
P - distal proximal plate
I - I bar

62
Q

What are three things to watch for when fabricating an RPI clasp

A

tori
frenum
shallow vestibule

63
Q

When is an RPI contraindicated

A

when there is a bony undercut below the bar or a high frenum attachment

64
Q

How is reciprocation provided in the RPI clasp

A

minor connector to the rest

proximal plate or guide plate to DL line angle

65
Q

What are the components of the RPA clasp

A

R - mesial rest
P - distal proximal plate
A - Akers clasp, just like the CC but the ENTIRE retentive arm is below the height of contour

66
Q

The wrought wire has what proportion above the HoC

A

2/3

67
Q

What is the fulcrum line

A

an imaginary line though the most posterior rest;indicates around which the denture tends to rotate under masticatory forces; involved with indirect retainers

68
Q

What are the components of the combo clasp

A

wrought retentive arm
distal occlusal rest
lingual reciprocating arm
distal proximal plate

69
Q

Which maxillary major connector is preferred for a Ken III

A

palatal strap

70
Q

Which maxillary major connector is preferred for a Ken I, II, or IV

A

anterior-posterior palatal strap

71
Q

At which distance from the FGM does the anterior-posterior palatal strap need to be located

A

5.0mm from FGM

72
Q

What is the width of the anterior/posterior strap

A

8-10mm to prevent flexibility

73
Q

What is the width of the lateral straps of the anterior-posterior palatal strap

A

7-9mm

74
Q

What should the minimum width of the palatal strap connector be

A

8mm; should be determined by the width of the edentulous space

75
Q

What is the approximate distance between struts

A

premolars; 7mm

molars; 10mm

76
Q

What is the proper width of the struts

A

1.5-2mm

77
Q

What is the proper distance between minor connectors

A

at least 5.0mm

78
Q

For the RPI clasp, the proximal plate needs to extend where

A

to the distal lingual line angle for reciprocation