Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Prosthodontics > Bridges > Flashcards

Bridges Flashcards

1
Q

Resin retained bridges

A

It is minimal or no tooth preparation
High quality framework - good mechanical properties, fit the abutment really well- cast non precious alloys (nickel chrome- not so often as contains barillium - when grinded is associated with carcinogens or chrome cobalt- more often)
High prosthodontic standards
Controlled adhesive techniques - depends on adhesives

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

Role of Torsion and bending in fixed prosthodontics

A

Mechanical principles needed to make a bridge:

Area of coverage- of the abutments

Thickness of retainers- to have rigidity

Control of the occlusion- controlling the load on the prosthesis

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

Three designs of fixed prosthesis requiring minimal or no tooth preparation

A
  1. Cantilever- one abutment supports one pontic
  2. fixed- fixed- retainer at each end of the spam- can carry more than one pontic
  3. Hybrid designs- one retainer is a crown and other retainer is resin bonded retainer

Simpler the design- better success
If only one abutment can hold the pontic- that is the best solution ( for resin retained bridges)
highest success rate- replacement of a single missing anterior tooth with only one abutment

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

Anterior cantilever bridge

A

Indications:
Short spans generally anterior
Using canine or central as abutment to replace lateral

Can be metal or all ceramic resin retained bridges - risk of fracture, ceramic is brittle ( higher connector height is needed, 3-4 mm)

Cantilever can be used in posterior teeth but in limited way- if occlusal load is okay ( premolar with molar) but not to cantilever molar to a molar due to increased occlusal loads on molars compared to anterior teeth ( length of the pontic span in molars in much more so should be avoided)

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

Fixed- fixed- resin retained bridge

A

Should be avoided

Yes if more pontics

Framework design- large coverage area
Retainer thickens of 0.7 mm , minimum needed
Good connector height - needed to keep the prosthesis rigid -2 mm
Control of the occlusion/occlusal contacts

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

Tooth preparation

A

No evidence that improves outcomes!
Only to prepare guide planes! For proximal coverage - need to be parallel as they contribute as resistance form of the bridge

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

Framework coverage

A

Coverage from incisal edge up to the wall apical to cingulum
Extension into the approximal areas adjacent to the pontic to give connector height
Maximum mesio-distal wrap-around
Minimum thickness of 0.7 mm

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

Post orthodontic retention

A

In adult teeth- fixed- fixed- is the choice as they have a memory and might go back to their original position if only cantilever is used( cantilever not stable)

Need:
Fixed-fixed design
Maximal coverage

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

Posterior tooth replacement

A

Classical design is 180 degree axial coverage
Rest seats adjacent to the pontic area
Good connector height
Control of occlusion

As aesthetics is not crucial, wings can be extended occlusal so that increased coverage gives increased security

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

Bridge is

A

Prosthetic tooth replacement that is fixed to at least one natural tooth or dental implant

Component parts ( fixed-fixed conventional bridge)- abutment tooth, retainer- means by which the bridge is attached to the abutment, connector-components of the bridge that attach the pontic to the retainer and pontic - prosthetic tooth

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

Tooth replacement options

A

Implants
RRB
Conventional bridge
Partial denture (acrylic-more as temorary, cocr)
Nothing (SDA)

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

Resin retained bridge

A

Retainer is metal wingrather than full coverage crown
Fixed (bonded to abutments)
Unremovable

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

Conventional bridge

A

Abutments are usually full coverage crowns (pontic is connected to 2 retainers)
Not conservative
Less torque compared with cantilever
Better for longer spans and where relatively heavy occlusal loads
There is significant biomechanical and biological issue

All joints are soldered or cast in one piece to rigidly connect all abutment teeth
Requires good retention at either end of the span
Preparation must be parallel with a single path of insertion/withdrawal

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

Contra indications for fixed prosthesis

A

Poor tooth prognosis
Young/growing PT due to large pulp horn and risk of pulp exposure on preparation
PT playing contact sports
Gross alveolar bone loss/resorption
Compromised teeth on either side of the bridge
Midline diastema (it will result in asymmetric pontic)
Pt compliance/motivation

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

Reasons for fixed rather than removable prosthetis

A

More acceptable to PT
No covering of gingival margin
Directs forces axially (non axial forces can cause occlusal trauma causing pain, mobility and pulp death)
Restores the occlusal anatomy
Orthodontic retention/ periodontal splinting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Conventional bridge fixed designs

A

Cantilever - single or double abutment, spring

Fixed-fixed
Fixed-movable
Hybrid

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

Conventional cantilever

A

Pontic is connected to the retainer at one end only.single retainer more conservative than 2

Leverage imposed on abutment teeth
Suitable for limited span length only

For short spans, mainly anterior
Not to be used with heavy occlusal forces on pontic

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

Double abutment cantilever

A

When pontic flexes, secondary abutments are in tension and may debond
Resistance is compromised and extra flexion of the bridge metal work when placed under load

Tensile forces are transmitted to distal retainer so cement failure can happen- risk of secondary caries as it is not possible to assess clinically the distal abutment (whereas mesial abutment stays cemented but not strong enough to take all the forces)

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

What records do you need to study and plan rehabilitation of this pt occlusion

A

Study models-to reproduce the articulating surface of teeth

Facebow- to locate maxillary study model to the condaylar component of the articulator such that it reproduces patients condylar movements

Interoclusal record in RCP - to relate maxillary to mandibular study model in precentric, this makes it possible to plan a reorganised occlusion should be required to for example if there is insufficient space for the aeshetic pontic

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

Appointment one-lab prescription

A

Pour the impressions in dental stone
And trim to study models
Please return metal stock trays
Mount the maxillary model on a Dinar semi adjustable articular using the facebow transfer jig provided. Locate the mandibular model to the maxillary model using the precentric occlusal beauty wax record.
Return the mounted model on the articulator in advance of the patients next appointments

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

Fixed prosthesis- biomechanical challenges

A

Conventional fixed movable bridge
- conventional because both abutments are heavily restored
-to distribute the relatively high occlusal loads between 2 abutments ( in contrast to doing a cantilever)
- If distal abutment is inclined, meaning a conventional fixed fixed bridge would require a lot of tooth reduction to allow for a single path of insertion

Hybrid fixed-fixed bridge
- if one tooth is unrestored- to preserve the tooth tissue placing only a wing and other tooth as conventional crown if it is heavily restored already
- better than cantilever so it can distribute relatively high occlusal loads between 2 abutments

22
Q

Recall intervals for bridges

A

NICE- dental checks: intervals between oral health reviews

SDCEP- oral health assessment and review dental clinical guidance

Discussing protective and modifying factors ( periodontal, caries, periapical, diet, no interdental cleaning, regular attendee)
Determining risk for oral disease
Stating the advised recall period should not exceed 6months

23
Q

What hard can restoration do

A

Impact on periodontal health (poor emergence profile, impingement on biological width)
Destruction of tooth tissue
Opens dentinal tubules (compromises pulp-dentine complex)
Starts restoration cycle

24
Q

Spring cantilever bridge

A

Little support to pontic, covers gingival margin
It was used to manage midline diastema
Used when adjacent teeth are not suitable abutments to farther teeth are used as abutments

Long connector is under more flexion

25
Q

Conventional fixed fixed bridge

A

Pontic is connected to 2 retainers
Not conservative
Less torque compared to cantilever
Better for long span
Can be used where relatively heavy occlusal loads
They are single rid entity so preparation needs a single path of insertion for both abutments (retainer preparation must be parallel to eachother, no undercuts)

Increase in taper- decreased resistance force and increased stress on cement)

26
Q

Occlusal forces

A

Direction of occlusal forces is dependent on position in the arch
Distance and direction of tooth movement during function translates to stress on lute
In fixed-fixed designs each abutment should provide equivalence of retention - addition of axillary features in weaker abutments - way to manage the load on weaker abutment

27
Q

Risks with fixed-fixed designs

A
  1. Biological consequences of tooth preparation
  2. Debonding of the weaker abutment
28
Q

Fixed movable design

A

For short span
To help with alignment of abutments
Depends on quality of abutments
And where abutments have independent mobility

For tilted teeth/abutments, different path of insertion

There is a fixed element of the bridge and the movable connector/joint between the two

29
Q

Golden proportional for the aesthetics/width of the tooth

A

It is what is seen when looking the pt from the frontz not actual width

If centrals are 100%
Laterals should be 65% of the width of the centrals
Canines shout be 85% of the width of the laterals

30
Q

Colour of the indirect restoration/matching

A

Hue-way to distinguish one colour from another
Chroma- amount of saturation in a given hue/ saturation of the colour
Value-most important, it determines the accuracy of colour matching

31
Q

What is metamerism

A

When a colour appears different under a different source of light

32
Q

Resin retained bridgework

A

Ideally:
Minimal, preferably no tooth preparation
High quality framework- good mechanical properties and fit the abutment well
High prosthodontic standards
Controlled adhesive techniqiet

33
Q

Survival rate of RRB

A

65% at 10 years
69% at 13 years
88 % at 5 years
77% at 10 years
80% at 10 years

34
Q

Hybrid designs

A

Not common
Useful alternative when there is one tooth that already has a crown/a tooth that needs a crown and one that has efficient enamel to be used as resin bonded retainer

It is not made in one piece
Resin retained bridge must be serviceable as if anything happens, it will be resin retained portion that will become uncemented

It has a movable connector that should always go to the distal surface of the minor abutment tooth( which is always more anterior)

They work better when the crown is more mesial rather than distal of the retainers and better

Producing parallelism in the gingival part of the crown prep is crucial/more important than in incisal portion

35
Q

Fitting surfaces of non precious metal for bridgework

A

Ceramic will bond to non precious metal but not other way around

Surface roughness can help with bonding but not enough
Sandblasting is needed just before cementation because non precious alloy is highly reactive and starts to produce oxide rapidly so there can be a layer of that risking the cohesive failure of the bond

36
Q

Harm restoration can do

A

Impact on periodontal health
Destruction of tooth tissue
Opening dentinal tubules
Starting restoration cycle

37
Q

Occlusal forces in bridges

A

The direction of occlusal forces is dependent on position in the arch
Distance and direction of tooth movement during function translates to stress on lute
In fixed-fixed designs each abutment should provide “equivalence of retention”

38
Q

Fixed-movable bridge

A

It is a stress breaker ( to allow a degree of differential vertical movement Between the pontic and the retainer)- reducing the forces applied on the weaker abutment
For angled abutments (different path of insertion)
Provision for failure
It is for:
Short span
Independent mobility of teeth

39
Q

Types of retainers

A

3/4 gold crown
Full veneer crown:
Gold
MCC
Ceramic

40
Q

Inlays as a retainer

A

Should be absolutely avoided
It is conservative but no cusp protection
Retention and resistance is much less than full coverage crown
Poor durability
Minimal impact of periodontium which is a good side

41
Q

3/4 gold crown as a retainer

A

More conservative than full coverage crown
Retention and resistance is poorer than full crown
Structurally weaker due to open face
Chamfer margin and modest occlusal reduction for gold is advantageous
Long margin can lead to failure- longer interface so leakage is possible
Supragingival margins are good for periodontal health
Poor/good aesthetics

42
Q

Full veneer gold crown as a retainer

A

Requires preparation of all coronal tooth tissue- relatively destructive
Very good retention and resistance
Structurally strong
Minimal prep for the gold
Can burnish margins to achieve good adaptation
Preservation of periodontium depends on margins and contour
Poor aesthetics

43
Q

Metal ceramic retainer

A

Requires preparation of all coronal tissue
Very good retention and resistance form
Structurally strong
Destructive prep
Preservation of periodontium depends on margins and contour if supragingival and well adapted
Good aesthetics

44
Q

All ceramic retainer/bridgework

A

Abutments need heavy preparation to give greater taper and thicker ceramic layer
Good resistance and retention
Questionable structural durability
Very aesthetic

45
Q

Abutment selection

A

Factors affecting the selection of abutment teeth:
Suitability of the pt (MH, DH - previous treatment, managing long appts…, SH - attendance, pafinance, consent, smoking, diet)

Suitability of oral environment (full dental charting, perio assessment - plaque, PPD, BoP, mobility, parafunctional habits, occlusion-occlusal scheme, toothwear)
Suitability of position of abutment
Suitability of tooth and supporting structures

46
Q

Assessing the suitability of the position of the tooth

A

Length of span-Ante’s law ( ideally, no more than 2 pontics for fixed-fixed and 1 for cantilever)
Curvature of span ( pontics lying outside of the inter -abutment axis will act as a lever)
Angulation of span (to achieve parallelism preps must be very heavy- unless fixed-movable design; non-axial loading of teeth-can cause occlusal trauma)
For fixed-fixed relative retention of individual abutments
Position of span in the arch

47
Q

Long span

A

Avoid due:
Flexing- stress to abutments and cement lute
Places increased load on PDL
Produce more torque on abutments

48
Q

Support of abutment teeth

A

Depends on:
Root configuration
Surface area
Length of clinical crown
Crown: root ratio( ideally 1:2, okay if 2:3 and could be acceptable 1:1)

49
Q

Ideal occlusion for a bridge

A

Posterior stability
Incisal/canine guidance
Absence of posterior interfaces on mandibular movements

No guidance on pontic for cantilever bridge- contact in ICP only (so the opposing tooth does not super erupt)

50
Q

Pontic design

A

Ridge lap
Modified ridge lap
Bullet
Ovate
Hygienic

Pontics are not an anatomical reproduction of the missing tooth but they should be:
Aesthetic
Functional
Cleanable
Compatible with mucosal health
Comfortable

*Pontic is an artificial tooth fixed on a bridge/partial denture replacing the missing tooth, restores its function and restores the space previous occupied by the clinical crown

51
Q

Consent info regarding RRB

A

Can debond (around 20% over 5 years)
Approx 90% survival over 5 years
Can be re cemented or may need to be remade

Prosthodontics (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions