Bridges I - Adhesive bridges Flashcards
What can adhesive bridges also be called?
Resin bonded bridge
Bonded bridge
Maryland bridge
How to retain a FPD?
Full coverage crowns - Prep of the abutment tooth is a full coverage crown e.g. FGC, PFM, all ceramic
Adhesive retainers - Prep of abutment tooth is minimal and involves palatal and proximal surfaces only
Use of abutments?
Fixed-fixed - The bridge spans from
one abutment to another, with the pontic
in between.
I.e.: Abutment – Pontic – Abutment
Cantilevered - bridge is retained by one abutment only e.g. abutment - pontic
Design criteria for adhesive bridges?
- Perio support
- Occlusal loading - magnitude and direction of force vectors
- . Conservation of tooth tissue
- Cleansability
- Appearance
- Rigidity (of retainer and connector)
- Qual of abutments
- No of abutments
- Choice of adhesive lute
- Contingency planning - what if it debonds, what if the tooth becomes non-vital
Features of single tooth and fixed cantilevered bridges?
More retentive than fixed fixed Pontic can move with the abutment Reduced shear forces on the pontic Debond leads to cleansable surfaces Risk of caries eliminated
When are adhesive bridges wanted? When do they work best?
Single tooth replacement
Work best when cantilevered from a good abutment tooth
What to consider with the framework design of adhesive bridges?
Retainer thickness and configuration Bonding area Wrap around Occlusal extension of metalwork Connector design Length of span
What to consider with retainer thickness and configuration?
Retainers for molars - 0.8mm thick
Greater if the retainer is not joined over the occlusal surface
What to consider with the bonding area?
Max enamel bonding
Extension of the metal work as far occlusogingivally and circumferentially around the tooth as possible
What is the max wrap around?
Max = 180 degrees (mesial and distal groove)
What is the occlusal extension of the metalwork?
- Full palatal coverage with no tooth prep
2. Reduced palatal coverage with tooth prep (finish 1-3mm short of incisal edge)
What is posterior occlusal coverage for?
Resistance to displacement apically or laterally
Increased rigidity of the framework
Greater surface area for bonding
What must the connector (metal wing joined to the pontic) design be?
Significant width and height required - at least 50% of the height of the pontic
Need to resist bending of the alloy
Must avoid putting adhesive lute under tensile loading
Length of span?
Ideally one tooth replacement
Longer spans are not contra-indicated, but the tooth prep and framework design should be planned to reduce potential debonding stresses on the retainer
What is needed to prep the tooth?
Axial tooth prep Grooves Occlusal rest seats Intracoronal prep Cantilevered resin bonded bridges