Resin Bonded Bridges

Resin bonded bridge is a minimally invasive fixed dental prosthesis that is luted to tooth structures, primarily enamel, which relies on composite resin cements for retention.

Types

• CANTILEVER
• FIXED-FIXED
• FIXED-MOVABLE
• HYBRID

Cantilever

• Involves the use of single retainer
• Abutment tooth maybe either mesial or distal
• Less expensive, but limited to replacing one
  missing tooth

Fixed-fixed

• One or more retainers are placed on either
  side of the pontic
• Differential movement of abutments can
  result in bond failure
• This design of bridge is indicated where
  excursive movements on pontics cannot be avoided

Fixed-movable

• Design is in two parts, keyed together by a
  non-rigid attachment
• Connector which may be either ready or laboratory-made,
  permits movement of the two parts relative to each other in vertical direction mainly
• Provides stress breaking action
• Should be used in short spans and where opposing
  proximal walls of abutment cant be prepared parallel

Hybrid 

• A combination of a conventional retainer at one end
  and a resin-bonded retainer at the other end of the pontic
• Indicated where one of the abutments is minimally restored,and a resin-bonded retainer is used at this site to conserve tooth tissue
• The male part of the joint is often attached to the
  resin-bonded retainer to simplify maintenance when de-bond occurs

 History

ROCHETTE BRIDGE

• Wing like retainers with perforations through them to enhance resin retention
• Macromechanical retention +
  silane coupling agent to produce
  adhesion to metal

MARYLAND BRIDGE

• An electrolytic etching procedure for non-precious ceramic bonding alloys to provide a microporous surface that allows micromechanical interlock with the cement
•  Thinner wings and no perforations

VIRGINIA BRIDGE (Lost Salt Technique)

• Salt crystals (150 to 250 μm) were incorporated into wax and removed in solution leaving cubic retentive pits
• Produces roughness on the inner surface of the retainer
• This was a time saving method and more retention is achieved compared to the technique of etching

CAST MESH FIXED BRIDGE

• A net like nylon mesh is placed over lingual surface of abutment teeth on the cast
• It is then covered by wax, with the undersurface of the retainer becoming mesh like when retainer is cast

Advantages of Resin bonded bridges

• Minimal tooth preparation

Beneficial incase of decay free teeth, large pulp chambers, slender lower incisors

• Expediency

Little need to provide temporary crown

Reduced chairside time; overall cost is minimal

• Convertibility

Less destructiveness

Possible to upgrade to a conventional
bridge without detriment to health of
abutment teeth

• Supra gingival margins

Mandatory for RBB

Soft tissue is undisturbed, facilitates plaque removal

• Acceptance by the patient

Technique involves minimum of “injections” and “drilling”

• Rebonding Possible

Disadvantages of Resin bonded bridges

• High failure rate

More frequent debond as compared to conventional

Plaque may trap underneath this de-bonded retainer, which can result in carious destruction if undetected

• Aesthetics

Problems can occur with incisal shine-through of metal if an opaque cement is not used

• —  Occlusal interferences

Mostly retained by lingually placed metal flanges

Not possible to reduce abutment teeth sufficiently

Frequent problem when upper arch is involved

• Redistrubution of space between pontic and abutment teeth
  
• Limited tooth replacement

Small spans tend to be more successful than large ones

• No Alignment correction

Indications

• Unrestored/minimally restored teeth
• Sufficient good quality enamel
• Sufficient inter-occlusal space for retainers
  exists
• Intermediate prosthesis prior to implants
• Large pulp chamber/ young patients
• Splinting periodontally compromised teeth
• Maxillary incisor replacements
• Single posterior tooth
  replacements

Contraindications

• Insufficient occlusal clearance
• Deep vertical overbite
• Thin and/or defective enamel
• Short clinical crowns
• Extensive loss of tooth structure
• Parafunctional habits
• Heavily restored teeth
• Nickel sensitivity