Dental Materials: Composite Flashcards
What are the components of composite resin?
Filler particles. Resin Camphoriquinone: Silane coupling agent Low weight di-methscrylates
What is an advantage of composite in terms of tooth tissue?
Composite conserves tooth tissue as it does not require retentive features to be cut into the tooth. Relies on bonding agents.
What is the function of a dental adhesives?
Bond COMPOSITE RESIN to enamel and dentine.
What is the function of etching enamel?
Dissolves some of the enamel rods to creature porosities which can be penetrated by the resin.
Polymerisation of the resin forms resin tags = strong bond.
What is the smear layer and where is it found?
Found on dentine. Created when dentine is cut by hand or handpiece. Mixture of debris, saliva and bacteria.
This debris can also be forced into the dentinal tubules = plug.
Define hybrid layer.
Resin infiltrates surface layer of dentine.
Strong bong as the resin monomer penetrates the dentine and is polymerised.
How is the smear layer removed?
Acid etch
What is HEMA?
A bi-functional resin monomer that primes dentine.
When should shade matching of composite be carried out?
Before the dental dam is placed (dam dehydrates the tooth and changes colour).
How should shade matching be carried out?
Matching carried out in natural light.
Patient should be involved in the decision.
What shade is B3?
Yellow
What is the function of bevelling?
Increases the surface area by cutting dentinal tubules longitudinally.
What are the two main types of dental bonding systems?
Etch and rise: 37% PHOSPHORIC ACID
Smear layer removed.
Self etch:
Condition and prime enamel/dentine at same time.
Smear layer penetrated and smear plugs occur.
What occurs if the etched dentine is over dried?
Collagen network collapses and shrinks.
What are the 2 components needed for free-radical polymerisation in self curing composites?
Aromatic tertiary amines.
Benzoyl peroxide.
