Resin retained bridges Flashcards
What is a RRB?
Fixed prosthesis that is bonded to one or more unprepared or minimally prepped teeth
What are the advantages of RRBs?
Fixed prosthesis
Conservative of tooth structure
No LA needed during prep
Short clinical time
Relatively inexpensive
Reversible/diagnostic
Why are canter-level bridges better than dentures?
Much more hygienic in design
What are the disadvantages of RRBs?
Aesthetic issues
- Greying of abutment teeth
- Metal showing over incisal edges
- Try in is difficult - esp in upper arch where there is no retention
- Temporising is difficult
- may need to use denture
- may need to accept space
What are the risks of a RRB debonding?
92% due to debonding
4% due to metal fractures
2% due to caries (greater risk of caries if partial debone from a fixed-fixed design)
Technique sensitive
What are the indications for an RRB?
Ideally single tooth replacement (RRBs with more than one pontic have been shown to have significantly increased debonding rate)
Unrestored abutment teeth or those with minimal restorations
Teeth with sufficient, good quality enamel for bonding
Intermediate prostheses in young patient prior to implant placement
What are the contraindications of RRBs?
Heavily restored abutment teeth
Abutments with lack of good quality enamel for bonding e.g. dentinogenesis imperfecta, acid erosion, small crowns
Excessive occlusal loading e.g. bruxism
Where diastomers are present
Poor OH
Difficulty in isolation
Translucent incisal edges
What is the cantilever design?
Eliminates the problem of partial debonding
Less expensive
Limited to releasing single anterior or premolar teeth
Biomechanically less stress on the resin lute was no differential movement issues
If it debonds, bridge just falls out
What is the fixed-fixed design?
Can provide periodontal splinting
Can provide orthodontic retention
Can restore multiple missing units
Needed when replacing anything other than a single anterior premolar unit
Differential movement of the abutment teeth can result in bond failure
What its hybrid design?
Has both resin-retained and conventional retainers
Indicated when one of the abutments is to be restored with conventional crown and the other is minimally restored
2 retainers may be joined by movable joint between pontic and conventional fixed retainer
What is the median survival of a fixed-fixed design?
7.8 years
What is the median survival of a cantilever design?
9.8 years
Why do fixed-fixed fail sooner?
Differential abutment movements
Increase stress on the metal framework
Which factors increase the success of a RRB?
Cantilever design
Greater operator experience
Minimal or no prep
Single pontic
Not using rubber dam
What is the clinical process of making an RRB?
Finishing:
- Remove XS cement, multi-fluted tungsten carbide burr
- Check occlusion
- Polish, white stone and then enhance polishing cup at 7000 rpm
- OHI - superfloss
- Occasional need to add composite to IP areas to hide metal framework
