Bonded Amalgam

Question 1

Benefits of bonded amalgam

Answer 1

• decreased micro leakage
• decreased recurrent caries
• decreased pulpal inflammation
• decreased post op sensitivity
• increased retention (bonded to tooth)
• increased fracture resistance of tooth
• decreased cuspal deflection
• treatment of cracked cusp
• conservation of tooth substance

Question 2

Indications of bonded amalgam

Answer 2

• heavily broken down coronal tooth structure - posterior
• high load bearing, large restorations - posterior
• core build up for posterior teeth before extra coronal restoration placement (crown)
• difficult moisture control conditions for a posterior composite which would contraindicate composite restoration placement
• nayyar core - post root canal treatment - endo

Question 3

Bonded amalgam theory

Answer 3

Micromechanical interlocking of amalgam and intermediate material
The intermediate material chemically bonds to the tooth.

Question 4

Disadvantages of amalgam bonding

Answer 4

• requires more clinical time
• more technique sensitive - additional stages involved
• more costly / expensive

Therefore generally used when additional retention and resistance features are required but where there is insufficient or weakened tooth tissue, in which to build in these features

Question 5

Adhesive bonding materials?

Answer 5

Resin modified glass polyalkenoate ((ionomer) cements
- chemical bond to tissues
- fluoride release

Resin cements
- chemically or light activated (Panavia)
- dual cured resin composite adhesive (Rely X)

Question 6

Step by step technique - Panavia 21 X

Paste-paste system delivered in a. Dual syringe dispenser that automatically dispenses equal amounts of base and catalyst paste

Answer 6

Standard prep guidelines -
Access carious lesion
Extend until the dentino-enamel junction is caries free
Remove loose friable enamel
Remove remaining dentinal caries
Internal line angles should be rounded
Lining?

1. Prepare the Panavia ED primer (mis equal amounts of bottle A and B)
2. Application of ED primer
   Apply ED primer to enamel and dentine for 60 seconds
   Evaporate the volatile ingredients using a gentle air flow until surface appears glossy