Brainscape's Knowledge GenomeTM

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


See full index

BDS4 > Fixed Pros > Flashcards

Fixed Pros Flashcards

1
Q

Indications for coring vital teeth

A

Vital tooth lost substantial amounts of tissue
RCT unnecessary + unlikely req. in near future
PD condition + hard tissues stable

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

What material is first choice for constructing core?

A

Amalgam

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

Dis/advantages of amalgam for cores

A

Adv

  • easy
  • cheap
  • good longevity
  • high compressive

Disadv

  • colour
  • nonadhesive
  • environmental issues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Discuss comp as core material

A

H2O inclusion over T (8% expansion)
Initial polymerisation shrinkage
Bonds tooth tissue: longevity questionable
- doesn’t bond metal pins/posts
Hard to pack; flowable easier
Aesthetics: good, makes difficult to distinguish b/w tooth + matieral

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

Types of dentine pins + associated problems

A

Types

  • cemented: least stress + retention
  • friction: high stress + retention
  • self tapping: medium stress + retention

Problems

  • stresses in dentine: microcracks-> microleakage -> failure
  • no bond to amalgam or comp
  • 2mm deep = close to pulp (exposure)
  • only reach 50-70% of hole prep: bacterial accumulate in space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Types of additional retention for amalgam cores

A

Slots + grooves: 2x2mm, 1mm from EDJ
Amalgapins: 2mm deep, large enough to use small instrument to pack
Adhesives

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

Discuss amalgam adhesives

A

Do not use
Unsuccessful: cause leakage = catastrophic failure
Never use w/ slots/grooves/amalgapins as fills space
Potential pooling around margin = inc. microleakage

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

Dis/adv of additional retention methods for amalgam cores

A

Adv

  • less stress on dentine (no binding force)
  • less corrosion: all same material
  • strength = to pin retained amalgam

Disadv

  • potential for exposure / perforation
  • req. rigid matrix otherwise # on removal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Problem w/ posting post. teeth + solutions

A

Problem
- Divergent, curved roots
— prep. for rigid cast/wrought post system = perforation
- Weakened by RCT access; weakened further by thick, rigid post

Solution
- plastic restoration + pins: potential for perforation
- plastic restoration within root canal system
— filled as continuum of support
- metal castings: custom for each pt

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

What is a Nayyar core?

A

Core for crown which extends into root canal system
Drill 4mm into canals w/ rose head or GG
Root canals + chamber packed w/ amalgam/comp and crown built up

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

Importance of carving amalgam/comp to full contour for cores

A

If flat opposing tooth may over-erupt!!

Check occlusion

  • cusp-to-tip relationship: tripod contacts
  • light ICP contacts, no excursive contacts

Easy to construct provisional

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

Problem associated w/ using comp for nayyar core

A

Dimensional stability: unable to prep immediately
- polymerisation shrinkage then expand thus crown wouldn’t fit

Cannot use eugenol containing cement

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

Compare tapered and parallel sided posts

A

Tapered

  • follows shape of tooth
  • more stresses
  • can # teeth

Parallel

  • good retention
  • red. stress
  • difficult to provide sufficient diameter for whole post length in narrow teeth
  • expensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Compare passive and threaded posts

A

Passive
- red. stress + retention

Threaded
- high stress (worse w/ tapered) + best retention

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

Discuss importance of length of post

A

Longer = better

> 50% canal length
than height of crown
Extend well below crest of bone
Leave 4mm GP @ apex

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

Effect of diameter of post

A

Wider = more bending resistance
However = red. tooth tissue, inc. chance #
Leave at least 2mm tooth tissue around

<1.25mm req. wrought post as gives cross sectional strength

17
Q

What is a RBB?

A

Minimally invasive fixed prostheses which relies on comp for retention
- FPD luted to etched tooth for resin retention

18
Q

Indications for replacing missing teeth

A

Aesthetics: ant.
Function: chewing, speaking, pt discomfort
Prevent OE/movement
Psychological comfort

19
Q

Components of RBB

A

Wing: attached to BA
Connector: attaches BA to BP
Pontic: artificial teeth

20
Q

Discuss RBB wing

A

Non-precious metal cast in thin section
Tx’d to inc. micromechanical adhesion
- protheses + comp
Ni-Cr/Co-Cr sandblasted 50micro Al

21
Q

Dis/advantages of RBB

A

Adv

  • min. invasive; relatively reversible
  • cheap cf implants
  • less clinical T
  • less demanding prep + fit
  • failure less catastrophic
  • aesthetic
  • predictable
Disadv
- aesthetics depend on BA tooth 
— quality + thickness of enamel 
— porcelain of Pontic
— extent of soft tissue defect in BP region 
— management of soft tissue 
- de-bond; re-bond less successful + predictable 
- longevity + success cf implant
22
Q

Principles of RBB design

A

Simple as possible
Cover as much BA poss + min. thickness (0.7mm)
Rigid: connector + wing
Hygienic pontic
Permit control of O contacts (BP not in excursion)

23
Q

Types of RBB

A

Cantilever
Fixed-Fixed
Fixed-Moveable
Hybrid

24
Q

Discuss design, dis/adv of cantilever bridges

A

Design

  • simple; 1 retainer
  • BA: M or D; D better longevity

Adv

  • simple
  • cheaper
  • good longevity
  • carious failure less likely
  • differential tooth movement = less stress on bond
  • higher success rate

Disadv

  • limited to 1 BP
  • most mechanically unsound; all stress transmitted to 1 BA
25
Q

Compare fixed-fixed and fixed-moveable bridges

A 
Fixed-Fixed
Design
- retainers: 1/+ either side BP
- connectors: rigid
Indications
- excursive movements unavoidable on BP
- long spans
- cross midline 
Adv: load distributed more equally
Disadv: differential BA movement = failure

Fixed-Moveable
Design
- connectors: 1 fixed (D) + 1 moveable
— allows some differential movement (vertical)
- 2 parts, keyed together by non-rigid attachment
Indication: where proximal walls BA can’t be prepped parallel
Adv: stress breaking action

26
Q

Discuss hybrid bridges

A

Design: combination of conventional + RBB

  • fixed-moveable: w/ resin retainer carrying moveable connector
  • fixed-moveable: w/ conventional retainer carrying moveable connector
  • fixed-fixed: 1 conventional + 1 RB retainer

Indication: 1 BA min. prepped so RB retainer used to conserve tooth tissue
Adv: allows variety of designs + retainers

27
Q

Factors affecting success of RBB

A 
Design: cantilever best
BA surface coverage: complete best
Connector height: long as poss
BA prep 
Metal surface Tx
Framework rigidity
Occlusal considerations
Span length
Operator experience
28
Q

Contra/indications of RBB

A

Indications

  • BA: sound, non-restored
  • good OH
  • occlusion well controlled
  • hypodontia
  • U+L I
  • single post.

Contraindications

  • BA: heavily restored, lack clinical crown height
  • bruxism or parafunction
  • extensive bone loss

BDS4 (10 decks)

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