Bridges Flashcards Preview

FRP - Crowns/Bridges/Wear/TMD/SDA/IMPLANTS > Bridges > Flashcards

Flashcards in Bridges Deck (30)
Loading flashcards...

tooth replacement options



indication for bridgework

Function and stability
Psychological reasons
Systemic disease e.g. epileptics
Co-operative patient
Big teeth
Heavily restored teeth
Favourable abutment angulations
Favourable occlusion


contraind of bridgework

Uncooperative patient
Medical history contra-indications
Poor oral hygiene
High caries rate
Periodontal disease
Large pulps
High possibility of further tooth loss within arch
Prognosis of abutment poor
Length of span too great
Ridge form and tissue loss
Surface area of root insufficient
tilting/rotation of teeth
poor periodontal condition


name some type of bridge designs

Fixed-fixed bridge
Cantilever bridge
•Conventional (Fixed)
•Adhesive/resin retained
Fixed-moveable bridge
Hybrid bridge
•Fixed retainer and adhesive retainer
Spring cantilever bridge


ADV of fixed-fixed design

Robust design
Maximum retention and strength
Abutment teeth splinted together ? (Perio)
Can be used in a long span
Laboratory construction straightforward


DIS of fixed-fixed design

-Need parallel prep
-Extensive tooth destruction
-Need minimal taper
-common POI needed


ADV of conventional cantilever

Conservative design
•Compared to fixed-fixed conventional design
Laboratory construction straightforward
No need to ensure preparations are parallel


DIS of conventional cantilever

Short span only
Rigid to avoid distortion
Mesialcantilever preferred?


important aspects of abutment evaluation

Must be able to withstand the forces previously directed to the missing teeth
Supporting tissues should be healthy and free of inflammation
•i.e.periapical disease and periodontal disease
Crown to root ratio
•length of tooth coronal to alveolar crest compared to length of root embedded in bone. Optimum ratio 2:3.
oMinimum ratio 1:1
Root configuration
Root surface area (periodontal ligament area)


what is ante's law

States that the root surface area of the abutment teeth should be equal or greater than that of the teeth being replaced with pontics.


ADV of Adhesive bridge

Minimal or no preparation
No anaesthetic needed
Less costly
Less surgery time
Can be used as a provisional restoration
If fails -usually less destructive than alternatives


DIS of Adhesive bridge

Uncertain longevity
Rigorous clinical technique
Metal shine-through
Can debond
•High chance of it debonding again
Occlusal interferences
No trial period possible


indication of adhesive bridgework

Young teeth
Less destructive
Good enamel quality
Large abutment tooth surface area
Minimal occlusal load
Good for single tooth replacement
Simplify partial denture design


contraind of Adhesive bridgework

Insufficient or poor quality enamel
Long spans
Excess soft or hard tissue loss
Heavy occlusal force e.g. Bruxist
Badly aligned, tilted or spaced teeth
Contact sports?


Treatment planning for bridgework

•Establish habits e.g. Bruxism
oDynamic occlusal relationships
Study models
•Mounted on semi-adjustable articulator with
•Consider diagnostic wax-ups


RRB - direct vs Indirect

•Very useful in emergency situation
•If tooth needs to be extracted immediately
•If tooth has been lost traumatically
•No preparation
•Minimal preparation
•Heavy preparation (Undesirable


what happens to CoCr in order to make it more retentive

sandblasted with Aluminium oxide 50 microns


anterior prep for cantilever

180º ‘wrap-around’ preparation
•Rest seats (posterior teeth)
•Cingulum rest (anterior teeth)
Proximal grooves
Supra-gingival chamfer finish line ~0.5mm
Ideally prep should remain in enamel
Cantilever design
Chamfer preparation
0.5mm supra-gingival
Cingulum rest
Proximal grooves


Posterior prep - cantilever

Occlusal rests
180º wrap-around with chamfer finish line
0.5mm supra-gingival
Proximal grooves
Can be cantilever or fixed-fixed design



27.88%failure rate 1-16 yrs
•Djemal S et al.(1999)
Overall survival after 4 years –79.6%
Cantilever bridges had greater survival than other bridge designs
Cantilever median survival: 9.8 yrs
Fixed-fixed median survival: 7.8 yrs


Information for bridge prep

•Presenting complaint
•Medical and social history
•Past dental history
Clinical examination (Extra-and intra-oral)
•Soft tissues
•Caries risk assessment
Abutment evaluation
•Remaining tooth structure
•Special tests


Abutment evaluation information

Root surface area and Crown-root ratio
•Ante’s Law
Root configuration
Angulation/rotation of abutment
Periodontal health
Surface area for bonding & quality of enamel
Risk of pulpal damage
Quality of endodontics:
•Re-root canal treatment?
Remaining tooth structure present?
•Remove and rebuild?
Post & core
•Remove and replace?


consideration for pontic design

•Should always be smooth, with highly polished or glazed surface
•Surface should not harbour join of metal and porcelain
•Embrasure space smooth and cleansable
oAs ‘tooth like’ as possible
oMay compromise
•Longer the span -Greater the thickness required to withstand occlusal forces


wash through pontic design, considerations

Wash-through: (Hygienic or Sanitary)
•Makes no contact with soft tissue
oFunctional rather than for appearance
oConsider in lower molar area


types of pontic design

wash through
dome shaped
modified ridge lap
ridge lap/saddle


dome shaped design considerations

Dome-shaped: (Torpedo or Bullet-Shaped)
•Useful in lower incisor, premolar or upper molar areas
•Acceptable if occlusal 2/3 of buccal surface visable
oPoor aestheitcs if gingival 1/3 of tooth visable


modified ridge lap considerations

Modified ridge lap:
Buccal surface looks as much like tooth as possible
Lingual surface cut away
Line contact with buccal of ridge
Problems with food packing on lingual surface of ridge


ridge lap/saddle design considerations

Ridge lap/Saddle:
Greatest contact with soft tissue
If designed carefully: can be cleansed
Less food packing than ridge-lap
Care taken not to displace soft tissue or cause blanching of tissue


preparation stages for a bridge

1. mounted study models/diagnostic wax up
2. Select shade
Laboratory made stent or make pre-operative putty impression for provisional bridge
Occlusal or incisal reduction
Separation of teeth
Aim for parallelismof tapered surface of each preparation
•Example: Preparation of fixed-fixed bridge for 13 1211
oPrep mesial of 11, then mesial of 13
oPrep distal of 11, then distal of 13
oPrep labial (2-planes) of 11, then labial 13 …..etc
3. Confirm parallelism
Consider retentive features if short clinical crown height or overtapered
•Slots or
Construct provisional bridge
Make impression and occlusal registration
Temporarily cement provisional bridge
Demonstrate cleaning with Superfloss™
Write/draw prescription for technician


importance of parallelism

Consider for fixed-fixedconventional bridge
•Requires two or more teeth to be prepared in a manner to provide a common path of insertion
•No undercuts but to give retentive preparations
Paralleling by eye
•Direct vision, one-eye closed
•Large mouth mirror (posteriorly)
•Use of a straight (right angle) probe like a laboratory surveyor, but in the mouth
Extra-oral survey
•Quick impression
•Pour a model
•Use a laboratory surveyor; useful in long span multiple unit bridges