Dental composite chemistry

C factor – ratio of bonded to unbonded surfaces in the preparation

Consists of

• Organic resin matrices
• Inorganic fillers consisting of proprietary combinations of zinc, alumina, silica, quartz, and zirconia.  This is where most of the evolution of composites has occurred.
• Pre-polymerized resins as a coupling agent

Silane – tris(2-methoxyethoxy) vinyl silane  bonds silica to polymer

JADA

 

Photo-initiator (photoinitiators)

1. Camphoroquinone (yellow) first one used after UV (1978).  Most common today at 470nm peak.  Disadvantage is yellow color and peak absorption in visible range.
2. Ivocerin (Dibenzoyl germanium derivative?) allows increase depth of cure for Tetric EvoCeram Bulk
3. Monoaclyphosphine oxide (Lucirin TPO 2,4,6-Trimethylbenzoyldiphenylphosphine oxide?)
4. Phenyl Propanedione (PPD)
5. Original composite used UV initiated chemical but was not in use for very long

Photoinitiators 2 and 3 are from an article I reviewed in General Dentistry. Different article that I like. Santini