The Four CORE™ Variables
 

4. Energy Requirement If the resin receives an inadequate amount of energy, it will not continue to cure and reach an adequate level of cure in 24 hours.

The amount of energy required to adequately polymerize a 2mm increment of composite resin can vary from as little as 8 Joules/cm² to as much as 24 Joules/cm², depending on the brand of resin and shade used.

Phillips' Science of Dental Materials (11th edition. St. Louis: W.B. Saunders Company; 2003) commonly used in dental schools across North America, recommends 16 Joules/cm². This is important as a given curing light in the hands of different operators could take anywhere from 4 seconds to 40 seconds to deliver the same amount of energy and fully cure the same 2mm of composite resin.