Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

REVISION BDS > RPD p622 > Flashcards

RPD p622 Flashcards

1
Q

support

definition

A

resistance of a denture to an occlusally directed load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

kennedy classification

is

A

describes number and distribution of edentulous areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

kennedy class I

A

bilateral free end saddle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

kennedy class II

A

unilateral free end saddle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

kennedy class III

A

unilateral bounded saddle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

kennedy class IV

A

anterior bounded saddle (crosses midline)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

modifications to kennedy classes

A

take most posterior saddle as main classification each edentulous area in addition to this takes one mode point

e.g. upper arch with 2 posterior bounded saddles and 1 anterior bouneded saddle would be kennedy class III mod2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

craddock classification

is

A

based on the support for the removable denture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

options for craddock classification

A

tooth borne

mucosa borne

tooth and mucosa borne

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

tooth borne support

A

provides hard tissue resistance to occlusal loading i.e. when there is abutment teeth with support on bounded saddles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

mucosa borne support

A

large covering provides resistance to occlusal loading

i.e. when the vertical biting force of the denture is resisted entirely by soft tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

tooth and mucosa borne support

A

reduced number of teeth and large edentulous saddles

i.e. large free end saddle with mesial rest and mucosal support

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what type of support is best

A

Tooth support is better as it transmits load through PD membrane, protects soft tissue, comfortable, more natural also doesn’t suffer
from muco-compressibility

Mucosal support may damage gingival margins and is more likely to displace, however large area=reduced occ. table

The best teeth for support are those with large root areas depending on PDL attachment
“A healthy tooth can carry 1.5x its own load”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

rests

role

A

provide support against vertically opposing forces and can also be used for reciprocation

Best used as part of a cast metal base alloy
➡i.e CoCr Base= CoCr rests
➡i.e PMMA Base= Stainless steel rest (however can fracture base if thin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

5 functions of rests

A
  • Prevent movement of RPD towards mucosa
  • Distribute occ. load
  • Direct retention to work in correct way
  • Prevent overeruption
  • Determine axis of rotation for denture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

factors for rest position

3

A

In tooth borne, rest should be nearest base

For tooth and mucosa should be on surface not near base

In free-end saddle rest is not placed immediately adjacent to saddle to prevent tilting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Every design

mucosal support

A

Contact points between Denture and abutment teeth
Wire stop at most posterior teeth to stop distal drift
Uncovered gingival margins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

7 basic support guidelines

RPD

A

Tooth support first choice

Bounded saddles tooth supported unless longer than 3 teeth

Rests must direct forces down long axis

Occlusion must be taken into account incase tooth prep needed

Mucosal support must cover a large surface area

‘Every’ design is a less harmful mucosa borne dentue

Mandibular mucosa supported RPD not recommended unless as training for complete denture or overdenture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

retention RPD

A

Resistance of a denture to lifting away from the tissues (vertical dislodging forces)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

direct retention

RPD

A

resistance to vertical displacement of teh denture

clasps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

modes of direct retention

A

mechanical - clasps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

clasps in RPD

A

placed below bulbosity of the tooth in the undercut

occlusally or gingivally approaching

single arm, circumferential or ring clasps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

RPD clasp design

A

section - round or half round

length - longer then length the greater the flexibility, must be at least 15mm

thickness - if reduced by 1/2 the flexibility inc by factor of 8

24
Q

clasp position and survey line

A

2/3 of clasp arm should be above the survey line

terminal 1/3 below the survey line engaging in the undercut

➡If not enough of an undercut it is possible to tilt the cast or use a composite build up *ONLY IN SMALL UNDERCUTS, OTHERWISE CLASP ARM WILL DE-BOND THE COMPOSITE
➡Alternatively you can prep an undercut with a crown bur

25
RPD rest types | 6
occlusal / incisal ledge onlay inlay hook ring (if occlusion tight)
26
CoCr clasp thickness
0.25mm
27
Au clasp thickness
0.5mm
28
Stainless steel clasp thickness
0.75mm
29
length of clasp
longer the length the greater flexibility, therefore clasp arm on molar must be 15mm at least
30
frictional retention by
guide planes
31
guide planes
provide frictional retention boudned saddle - have 2 or more parallel axial surfaces on abutment teeth which limit the POI and improve stablity can be natural or prepped larger the guide surface = the more efficient it is
32
altered path of insertion effect
eliminates undercuts (in common path of insertion) and creates new ones for retentive elements common PoI = 90 degrees tilt anterior or posterior to create new ones
33
muscular retention
in resting position from orbicularis oris and buccinator
34
RPI is a
stress reliving clasp system
35
RPI used in
distal extension saddles kennedy I and II
36
RPI components
Mesial Rest (Occlusal), Rounded on impression surface Proximal Plate (adjacent to saddle) guide surface of 2-3mm, with an undercut at tooth bulbosity to permit movement I-bar clasp (gingivally approaching) at the greatest prominence of tooth contour
37
how does RPI work
Mesial rest is loaded Proximal plate rotates into the distal undercut I-bar clasp rotates into mesial undercut and isn’t touching tooth (it lies on largest bulbosity of crown before loading)
38
5 methods of direct retention in RPD
mechanical retention - clasps frictional retention - guide planes altered PoI muscular retention RPI
39
indirect retention | definition
resistance to rotational displacement of teh denture
40
types of indirect retention | 6
- Indirect Retainers - Major Connectors - Minor Connectors - Rests - Saddle - Denture
41
indirect retainers principles
resists rotation around a ‘fulcrum axis’. * (*fulcrum axis = the line of rotation – it is an imaginary line between the most posterior rest seats on the end of each arch) * (* clasp axis = imaginary line between clasps on opposite sides of the arch) When there are multiple clasp axes, use the one closest to the saddle, this is the MAJOR one. *Rests should be 90 to their potential path of movement in order to behave as indirect retainers*
42
reciprocation in RPD design
resistance to side to side movement Reciprocation is placed opposite to retentive clasp to assist in preventing unwanted movements/stresses of abutment teeth: * Reciprocating arms provide some resistance but also allow flexure so that the retentive arm does not get put under too much pressure and break. * Reciprocating clasps still need to engage undercut * Try and encircle the tooth by 180 degrees Guide planes * Place suitable rigid components of the denture to resist horizontal and vertical forces. RPI system – minor connector on mesial rest of tooth prevents excessive distal movement. Bracing = general resistance to lateral movements exerted on the denture by tissues: * Maxilla – palate and alveolar ridge can be taken advantage of * Flatter ridge = more movement * Major connector and flanges can be useful to help with bracing – this should be incorporated into the design.
43
indirect retention principles
Principles * Retentive clasps should always be between the saddle and indirect retainer * Retentive clasps should be as close to saddle as possible, whilst the indirect retainer is as far away from saddle as possible. * Try not to have movements that will force pressure on a tooth/ortho movement.
44
maxillary major connectors options
can be open (better OH) or closed (greater retention)
45
mandibular major connecotrs options
plate or bars
46
mandibular plates
Can be thin in cross section and maintain rigidity * 0.5mm only recommended in mandibular arch where there is no space for a bar (because they will have to cover gingival margins) When less tooth support plates will confer mucosal support leave free gingival margin where possible (3mm from GM for > 1.5 teeth)
47
mandibular bar
Less coverage of gingival margins Must be thick to maintain rigidity * 2mm thickness Default connector in mandibular arch
48
lingual bar space requirements
8mm total ➡3mm- Distance from gingival margin ➡4mm- Height of the bar ➡1mm- Above floor of the mouth
49
mandibular major connector options
lingual bar (needs 8mm, 2mm thickness) sublingual bar (4mm thickness) kennedy bar/continual lingual clasp - on 2/3 of teeth lingual plate - 0.5mm thickness, but gingival coverage
50
minor connectors definition
join components such as rests to the major connector tranfer functional stresses to and from teh abutment teeth
51
requirements for minor connectors | 4
rigid finish above the survey line cross gingival margin at right angles (easily cleaned) cover as little of gingival tissue as possible
52
checklist for RPD setting teeth
- Contact points - Use existing teeth to guide in 3 dimensions - ICP for posterior teeth, make sure they are as centric as possible **- Occlusal dimension maintained (pin on table w/ articulator)** **- Artificial teeth set to conform with existing occlusion** - Refinement must be done in occlusion intra-orally (at chairside)
53
components used to survey casts
Analysing rod Undercut gauges * 1 line- 0.25mm- CoCr * 2 lines- 0.5mm- Au * 3 lines- 0.75mm- Stainless Steel Surveying table Surveying arm Graphite marker
54
curve of spee
curvature of the mandibular occlusal plane beginning at the tip of the lower incisors and following the buccal cusps of the posterior teeth, continuing to the terminal molar
55
curve of wilson
The curve of Wilson is the across arch curvature or posterior occlusal plane. Arc of the curve, which is concave for mandibular teeth and convex for maxillary teeth are defined by a line drawn from left mandibular first molar to right mandibular first molar
56
sphere/curve of monson
The curve of occlusion of natural teeth in which each cusp and incisal edge touches or conforms to a segment of the surface of a sphere, with its centre in the region of the glabella.

REVISION BDS (43 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions