Composits Flashcards
What etch is used in clinic?
37% phosphoric acid
How long should enamel be etched?
20 seconds
What does the adhesive resin (bonding agent) do?
It acts like glue to connect the composite filling to the tooth.
What is the initiator for a light cured resin?***
Camphorquinone
What is Resin?
In polymer chemistry and materials science, resin is a “solid or highly viscous substance” of plant or synthetic origin that is typically convertible into polymers. They are often mixtures of organic compounds.
Mircrofilled Composite size
0.01-0.012 um
Microhybrid composite size
0.01-3um
Fine partial composite size
0.5-3um
Dentin etch time
10s
When bonding to dentine The bond strength is primarily influenced by micromechanical bonding to
intertubular dentin (between tubules)
What is the purpose of the primer?
…transforms a hydrophilic tissue state into a hydrophobic one…
The general rule is that one should apply as many layers as are necessary to produce a…
persisting glistening appearance on dentin.
6th Generation Bonding System
Etch and primer are in the same bottle. Less technique sensitive, but decreased bond strength.
7th Generation Bonding System
Etch, primer, and adhesive resin are in the same bottle. The least technique sensitive, but lowest bond strength.
Most common acrylic used in dentistry Commonly used for dentures and temporary crowns
Poly methyl methacrylate (PMMA)
Properties of PMMA
Shrinks during the polymerization process Setting reaction is exothermic (produces heat)
When monomer and polymer are mixed in the proper proportions, a workable mass is produced. Upon standing, the resultant mass passes through five distinct stages. These stages may be described as :
(1) sandy
(2) stringy
(3) doughlike
(4) rubber y or elastic
(5) stiff
Acrylic initiation, What is the activator and what is the initiator
Activator: Chemical (3° Amine)
Initiator: benzoyl peroxide
Sweetish odor that is toxic if inhaled for
prolonged period
and The polymerization process converts the
material to a solid with essentially no vapor
pressure
Monomer
Light activated Triad is called…
Urethane dimethacrylate
Light activated initiator of acrylic is…
Camphorquinone
