Configuration factor

In dentistry, the configuration factor (also known as c-factor) refers to the number of bonded to unbonded surfaces in a tooth preparation. For instance, in an occlusal class I preparation there would be 5 bonded surfaces and only 1 unbonded surface. The net result would be a C factor of 5. As the C factor increases so to does the possibility of bond disruption when using a composite resin. This effect is caused by a reduction in unbonded surfaces in which the composite can "flow" to relieve polymerization stress. The technique of incremental layering has been suggested to compensate for preparations with high configuration factors.

Roberson, Theodore; Haymann, Harold; Swift, Edward (2002), Sturdevant's Art and science of Operative Dentistry, St. Louis, Missouri: Mosby.